Marine natural products

Contents

• 1 Introduction

• 2 Reviews

• 3 Marine microorganisms and phytoplankton

• 4 Green algae

• 5 Brown algae

• 6 Red algae

• 7 Sponges

• 8 Coelenterates

• 9 Bryozoans

• 10 Molluscs

• 11 Tunicates (ascidians)

• 12 Echinoderms

• 13 Miscellaneous

• 14 Conclusions

• References

---

Abstract

Covering: 2005. Previous review: Nat. Prod. Rep., 2006, 23, 26

This review covers the literature published in 2005 for marine natural products, with 704 citations (493 for the period January to December 2005) referring to compounds isolated from marine microorganisms and phytoplankton, green algae, brown algae, red algae, sponges, coelenterates, bryozoans, molluscs, tunicates and echinoderms. The emphasis is on new compounds (812 for 2005), together with their relevant biological activities, source organisms and country of origin. Biosynthetic studies, first syntheses, and syntheses that lead to the revision of structures or stereochemistries, have been included.

---

John W. Blunt

John Blunt obtained his BSc (Hons) and PhD degrees from the University of Canterbury, followed by postdoctoral appointments in Biochemistry at the University of Wisconsin-Madison, and with Sir Ewart Jones at Oxford University. He took up a lectureship at the University of Canterbury in 1970, where he is now a Professor. His research interests are with natural products, and the application of NMR techniques to structural problems.

Brent R. Copp

Brent Copp received his BSc (Hons) and PhD degrees from the University of Canterbury, where he studied the isolation, structure elucidation and structure–activity relationships of biologically active marine natural products under the guidance of Professors Blunt and Munro. He undertook postdoctoral research with Jon Clardy at Cornell and Chris Ireland at the University of Utah. 1992–93 was spent working in industry as an isolation chemist with Xenova Plc, before returning to New Zealand to take a lectureship at the University of Auckland, where he is currently a Senior Lecturer.

Wan-Ping Hu

Wan-Ping Hu received her BSc (Hons) and PhD degrees from the University of Canterbury, where she studied molecular beams with Professor Peter Harland. She carried out postdoctoral research with Professor Stephen Price at University College London before returning to New Zealand where she is currently a research associate at the University of Canterbury working on breath testing projects using SIFT-MS for clinical studies, in addition to maintenance of the MarinLit database.

Murray H. G. Munro

Murray Munro, University of Canterbury, Christchurch New Zealand, has worked on natural products, mainly of New Zealand origin, right through his career. Following a sabbatical with Ken Rinehart at the University of Illinois in 1973, interest in marine natural products developed with a particular focus on bioactive compounds. In recent years his research interests have widened to include terrestrial and marine fungi and actinomycetes as well as marine invertebrates.

Peter T. Northcote

Peter Northcote received his BSc and PhD degrees from the University of British Columbia, Canada where he was a member of R. J. Andersen's marine natural products research group. He carried out postdoctoral research with Professors Blunt and Munro at the University of Canterbury before taking a position as a senior research scientist at Lederle Laboratories, American Cyanamid Co. He joined the faculty of the Victoria University of Wellington in 1994 where he is currently an Associate Professor in organic chemistry.

Michèle R. Prinsep

Michèle Prinsep received her BSc (Hons) and PhD degrees from the University of Canterbury, where she studied the isolation and structural elucidation of biologically active secondary metabolites from sponges and bryozoans under the supervision of Professors Blunt and Munro. She undertook postdoctoral research on cyanobacteria with Richard Moore at the University of Hawaii before returning to New Zealand to take up a lectureship at the University of Waikato, where she is currently a Senior Lecturer.

---

1 Introduction

This review is of the literature for 2005 and describes 812 new compounds from 283 articles, an increase of ∼13% from the number of compounds reported for 2004. As in previous reviews, we show structures only for new compounds, or for previously reported compounds where there has been a structural revision or a newly established stereochemistry. Previously reported compounds for which first syntheses or new bioactivities are described, are referenced, but separate structures are generally not shown. In a departure from past practice, no reference is made in the text to the establishment of absolute stereochemistry when standard methods (e.g. Mosher, Marfey, X-ray crystallography) have been used, unless there are some unusual features associated with the use of these techniques. However, where such determinations have been made for a compound, that compound's identifying number in the diagrams is distinguished by addition of a †. Stereochemistries shown for compounds not labelled with † should be assumed to be relative.

It is with great sadness that for a third year we note the passing of a chemist eminent in the field. On 3 February 2006 our colleague Pierre Potier, Professor of Chemistry at the Muséum National d'Histoire Naturelle in Paris, Member of the French Academy of Sciences and former Director of the Institut de Chemie des Substances Naturelles, passed away. Professor Potier was noted for his inspirational work on anticancer drugs and in the marine area for his pioneering marine natural product work in the New Caledonia area including the advancement of girolline towards clinical trials.

2 Reviews

There continues to be a steady stream of reviews on specific topics within marine natural products, but with only one review¹ giving overall coverage of the 2003 literature. Several reviews explore the development of marine compounds as drugs.^2–6 There have been reviews on aspects of the chemistry and bioactivity of compounds from soft corals,⁷ cyanobacteria and microalgae,⁸ cyanobacteria and macroalgae,⁹ sponges,^10,11 cnidaria,¹² hoplonomertea, platyhelminthes, polychaetes, bryozoans and hemichordata,¹³ echinoderms,^14–16 ascidians and fish,¹⁷ the gorgonian Pseudopterogorgia elisabethae,¹⁸ ascidians of the genus Aplidium,¹⁹ the sponge genus Halichondria,²⁰ and terpenes from the soft coral genus Sinularia.²¹ Specific types of bioactivity associated with marine natural products have been reviewed in articles on anticancer drugs,²² agents for treating tuberculosis, malaria, osteoporosis and Alzheimer's disease,²³ antifoulants,²⁴ treatments for neurological disorders,²⁵ anti-inflammatory agents,^26,27 anti-HIV compounds,²⁸ and topoisomerase inhibitors.²⁹ Growing interest in marine microorganisms is reflected in several reviews.^30–35 Reviews on several aspects of the chemistry,^36–38 toxicology,^39–41 assay,⁴² and risk factors^43,44 of marine toxins have appeared. Particular classes of compounds from marine organisms continue to be well reviewed, with offerings on pyrroloiminoquinone alkaloids,^45,46 polymethyleneamine alkaloids,⁴⁷fatty acids from lipids ,⁴⁸ indole alkaloids,^49,50 guanidine derivatives,⁵¹ bromopyrrole alkaloids,⁵² phenylpyruvic acid oxime derivatives,⁵³triterpenoids ,⁵⁴ imidazole, oxazole and thiazole alkaloids,⁵⁵ sponge alkaloids,⁵⁶ iminium alkaloids,⁵⁷ diterpene-containing adenine alkaloids,⁵⁸ unusual sterols from sponges,⁵⁹ and briarane-related diterpenoids .⁶⁰ There have been several reviews for different classes of compounds from all natural sources, but where the contributions from marine sources are relatively minor, such reviews have not been noted here. Biosynthesis of marine natural products in microorganisms⁶¹ and molluscs⁶² has been reviewed, and the use of microbial genetics to ensure adequate supplies of marine compounds for development as drugs is surveyed.⁶³ The role of symbiotic bacteria in metabolite production and the analysis of the appropriate biosynthesis gene clusters has been reviewed.^64,65 In the first of what is expected to be a continuing series, a broad review on synthetic aspects of marine natural products covering publications in 2003 has appeared.⁶⁶ More specific reviews that appeared in 2005 relating to the synthesis of marine natural products will be referenced in the third of that series. There has been a useful review of the methods used for the isolation of marine natural products.⁶⁷ The MarinLit database⁶⁸ continues to be updated and has again been used as the basis for the preparation of this present review.

3 Marine microorganisms and phytoplankton

Microorganisms continue to be a productive and successful focus for much marine natural products research. The actinomycete Salinispora tropica, that had previously yielded salinosporamide A,⁶⁹ also contained several related metabolites, salinosporamides B1 and C2⁷⁰ and the unprecedented chlorinated macrolides sporolides A3 and B4.⁷¹
The structures of the sporolides are remarkable in that 23 of the 24 carbons of the skeletons are either oxygenated or sp² hybridised.⁷¹ Salinosporamides A and B1 inhibited human colon carcinoma HCT-116 cells with salinosporamide A being the most potent. Salinosporamide A also exhibited extreme potency against several non-small cell lung, CNS and breast cancer cell lines at the NCI.⁷⁰ A new genus of actinomycete from deep water sediment (La Jolla, California) has yielded three chlorinated dihydroquinones 5–7. Two known analogues were also isolated,^72,73 with the absolute configuration of one of these analogues established recently⁷⁴ and that of the other, 8, reported in 2005.
Compounds 5–8 displayed significant activity against methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus faecium (VREF), and were cytotoxic to human colon carcinoma HCT-116 cells.⁷⁵Thallusin9, isolated from an epiphytic marine bacterium obtained from the surface of the green alga Monostroma oxyspermum (Japan),⁷⁶ is a potent differentiation inducer of M. oxyspermum and induced germination in other green macroalgae.⁷⁷ A Thermoactinomyces species isolated from mud (Mecherchar, Republic of Palau) was the source of the cyclic peptide mechercharmycin A10 as well as the linear congener mechercharmycin B11.⁷⁸
Mechercharmycin A10 was active against A-549 lung and Jurkat human leukaemia cell lines, and was also reported as a cytotoxic compound in a patent also published in 2005.⁷⁹ A yellow pigment 12, an analogue of the tambjamine alkaloids,^80–82 has been isolated from the marine bacterium Pseudoalteromonas tunicata⁸³ (source not given).⁸⁴ Cell-free culture supernatant of the psychrophilic aerobic bacterium P. haloplanktis obtained from seawater (Dumont d'Urville station, Antarctica) contained a diketopiperazine 13. Two further diketopiperazines, known synthetic compounds,^85,86 were reported for the first time from a natural source. Two linear peptides 14 and 15, stable to bacterial proteolytic enzymes, were also isolated.
Peptide 15 displayed antioxidant activity in the 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging assay.⁸⁷Streptomyces nodosus, isolated from marine sediment (Scripps Canyon, California), yielded the antibiotic lajollamycin16 active against both drug-sensitive and drug-resistant Gram positive microorganisms and inhibited growth of the murine melanoma cell line B16-F10.⁸⁸ The chlorine-containing manumycin derivatives, chinikomycins A17 and B18 were isolated from a Streptomyces species obtained from sediment (Jiaozhou Bay, China). Both 17 and 18 displayed antitumour activity against a number of human cancer cell lines.⁸⁹
A Streptomyces species isolated from an unidentified sponge (Jaeju Island, Korea) was the source of the cyclic peptides dehydroxynocardamine19 and desmethylenylnocardamine20, weak inhibitors of the recombinant enzyme sortase B.⁹⁰ The pyrrolosesquiterpenes, glaciapyrroles A–C21–23 were obtained from a Streptomyces species isolated from marine sediment (Alaska). Glaciapyrrole A21 exhibited activity against HT-29 and B16-F10 cell lines.⁹¹ A resistomycin derivative, 1-hydroxy-1-norresistomycin24, has been independently isolated from different cultures of sediment-derived Streptomyces species, one from Laguna de Terminos, Gulf of Mexico⁹² and the other from Streptomyces chibaensis (Bay of Bengal, India).⁹³ Compound 24 was active against E. coli, S. aureus and Streptomyces viridochromogenes⁹² and cytotoxic to HMO2 (gastric adenocarcinoma) and HePG2 (hepatic carcinoma) cell lines.⁹³Feigrisolide C25, isolated originally from Streptomyces griseus,⁹⁴ was also isolated from a marine Streptomyces species.⁹⁵
Structures proposed in each instance have been corrected by chemical reactions of natural feigrisolide C and confirmed by total synthesis.⁹⁶ From a North Sea strain of Streptomyces, new methyl branched γ- and δ-lactones 26–31 were obtained along with two previously reported lactones ^97,98 isolated for the first time from a natural source.⁹⁹ A Streptomyces species from marine driftwood (West Coast, New Zealand) gave four new cytotoxic anthracycline derivatives (7S*,9R*,10R*)-pyrromycin32, (7R*,9R*,10R*)-pyrromycin33, 1-hydroxyauramycin T34 and 1-hydroxysulfurmycin T35.¹⁰⁰
An Actinomadura species from sea sediment (Jiaozhou Bay, China) contained the staurosporine analogue ZHD-050136, an inhibitor of the proliferation of a variety of murine and human cancer cell lines.¹⁰¹ The phenolic bisabolane sesquiterpenoids (+)-curcutetraol37 and (–)-curcutriolamide38 were isolated from a co-culture of unidentified bacterium and fungus separated from marine sediment (Bahamas). Total synthesis of (±)-curcutetraol was achieved in seven steps from o-hydroxy-p-methylacetophenone.¹⁰²2,5-Dimethyl-3-(methylsulfanyl) pyrazine39, one of several 2,5-dialkylpyrazines identified in extracts of the Alphaproteobacteria Loktanellasp. (North Sea), has been previously reported as a flavouring agent¹⁰³ but this was the first isolation from a natural source.¹⁰⁴Himeic acids A–C40–42 were isolated from an Aspergillus species separated from the mussel Mytilus edulis (Toyama Bay, Sea of Japan).
Himeic acid A40 inhibited the ubiquitin-activating enzyme E1.¹⁰⁵Aspergillus varians (Sakhalin Island, Russia) yielded the known compound patulin¹⁰⁶ and 43, the 4-epi-isomer of a known compound.¹⁰⁷ This is the first report of patulin from the marine environment. Both compounds were active against the sea urchin Strongylocentrus intermedius, cytotoxic to embryos and spermatoxic to sperm.¹⁰⁸ The cerebroside asperiamide A44 has been reported from a fungus described as Asperillussp. (presumably Aspergillussp. ) isolated from seawater (Mei-Zhou Gulf, China).¹⁰⁹Scalusamides A–C45–47, pyrrolidine alkaloids, originated from Penicillium citrinum separated from the gastrointestine of the parrot fish Scalus ovifrons (Hedo Cape, Okinawa).
The absolute configuration of C-2 was established as (R), but all three compounds were shown to be epimeric mixtures at C-7. Scalusamide A45 showed weak antifungal activity against Cryptococcus neoformans and antibacterial activity against Micrococcus luteus.¹¹⁰ The same fungus also yielded the tetracyclic alkaloid , perinadine A48, weakly active against L1210 cells and was antibacterial against M. luteus and B. subtilis.¹¹¹P. citrinum, separated from the red alga Actinotrichia fragilis (Hedo Cape, Okinawa), was the source of citrinadin B49 and the previously isolated citrinadin A50.¹¹²
Citrinadin B49 was modestly cytotoxic against L1210 cells.¹¹³ Two sorbicillin-derived alkaloids, the sorbicillactones A51 and B52, were isolated from a saltwater culture of P. chrysogenum, separated from the interior of the sponge Ircinia fasciculata (Bight of Fetovaia, Sicily). The biosynthesis of sorbicillactone A51 was examined with ¹³C-labelled precursors and found to arise via an unprecedented pathway from acetate, S-adenosyl methionine, alanine and a biosynthetic equivalent of fumaric acid. Sorbicillactone A51 was active against HIV, had neuroprotective potential and was selectively active against L5178y cells.¹¹⁴Penicillium terrestre from marine sediment (Jiaozhou Bay, China) generated a number of new metabolites; the polyketides penicillones A53 and B54,¹¹⁵ two benzoquinone derivatives 55 and 56, two bisorbicillinoids 57 and 58¹¹⁶ and the bisorbicillinoids dihydrotrichodimerol59 and tetrahydrotrichodimerol60.¹¹⁷
Trichodimerol^118–120 was isolated from a marine source for the first time.¹¹⁷ Against the P388 and A-549 cell lines, dihydrotrichodimerol 59 and tetrahydrotrichodimerol 60 were cytotoxic,¹¹⁷ bisorbicillinoids 57 and 58 were antiproliferative,¹¹⁶penicillone A53 displayed weak cytotoxicity while penicillone B54 was weakly cytotoxic to A-549 cells only.¹¹⁵ The diastereoisomeric quinolinones 61 and 62 were isolated from P. janczewskii derived from surface water (German Bight, Helgoland Island). Both compounds were cytotoxic to a range of human tumour cell lines, with 62 strongly cytotoxic to SKOV-3 cells (human ovarian carcinoma).¹²¹P. auratiogriseum, derived from the sponge Mycale plumose (Qingdao, China), was the source organism for the benzoate 63, a cytotoxic agent against tsFT210 cells.¹²² A new xanthocillin 64 and three known xanthocillins,¹²³ all thrombopoietin mimics, were isolated from a marine Basipetospora species (source not given).¹²⁴
On fermentation, the fungus Clonostachys rogersoniana from the sponge Halichondria japonica (Numazu, Japan), gave the cyclic nonapeptides, clonostachysins A65 and B66, motility inhibitors of the dinoflagellate Prorocentrum micans.¹²⁵
The mitosporic fungus Geniculosporumsp. associated with a red algal Polysiphonia species (Ahrenshoop, Baltic Sea) was cultured to yield eleven new botryane compounds 67–77, some of which displayed modest growth inhibition of alga, bacteria and fungi.¹²⁶
Myrothenones A78 and B79, new amino-5-ethenylcyclopentenones, were obtained from the fungus Myrotheciumsp. isolated from the surface of the green alga Enteromorpha compressa (Busan, Korea). Myrothenone A78 inhibited tyrosinase.¹²⁷ The polyketide glycoside , cladionol A80, isolated from the fungus Gliocladiumsp. , separated from the sea grass Syringodium isoetifolium (Maeda Cape, Okinawa), was moderately cytotoxic to L1210 and KB cells.¹²⁸Emericella variecolor, isolated from marine sediment (Gokasyo Gulf, Japan), yielded the polyketide shimalactone A81, a compound which induced neuritogenesis in neuroblastoma neuro-2a cells at low concentration, but was cytotoxic at higher concentration.¹²⁹Peribysins E–G82–84, from Periconia byssoides, separated from the sea hare Aplysia kurodai (Osaka, Bay of Japan), were inhibitors of adhesion of human leukaemia HL-60 cells to human umbilical vein endothelial cells (HUVEC).¹³⁰ The absolute configuration of the known peribysin A85¹³¹ was established.
Four novel diterpenoids , libertellenones A–D86–89, were isolated from a co-culture of a marine α-proteobacterium and an established culture of the fungus Libertellasp. separated from an ascidian collected in the Bahamas. The metabolites were not found in pure cultures and are proposed to be of fungal origin. The bacterium used was isolated originally as a contaminant of a fungal culture and was the same strain which induced pestalone production in another marine fungus.¹³² The libertellenones exhibited cytotoxicity against HCT-116 cells with 89 being the most potent.¹³³ A Cladosporium species associated with the Red Sea sponge Niphates rowi (Gulf of Aqaba) was the source of a hexaketide pandangolide 1a90, and the known diastereomer pandangalide 191,¹³⁴ along with iso-cladospolide B92.¹³⁴
Absolute configurations of 90–92 were determined by Riguera's method¹³⁵ and circular dichroism , and confirmed the absolute configuration of 92 suggested previously.^136,137Phomopsis asparagi, from the sponge Rhadphidophlus juniperina (U.S. Virgin Islands), produced chaetoglobosin-51093, chaetoglobosin-54094 and chaetoglobosin-54295 when challenged with the known F-actin inhibitor¹³⁸ jasplakinolide¹³⁹/jaspamide¹⁴⁰ obtained from Jaspis sponges.
Chaetoglobosin-54295 had antimicrofilament activity and was cytotoxic towards L1210 and C38 cell lines.¹⁴¹Xyloketal G96 was isolated from the marine-derived mangrove fungus Xylariasp. separated from seeds of an angiosperm (Mai Po, Hong Kong),¹⁴² while a Xylaria species isolated from seeds of the mangrove Avicenna marina (Hong Kong) produced the dimeric xyloketal F97. Xyloketal F was a potent L-calcium channel blocker while xyloketals A and B¹⁴³ were also blockers, but less potent.¹⁴⁴Diaporthelactone98, and the known compounds 7-methoxy-4,6-dimethyl-3H-isobenzofuran-1-one¹⁴⁵ and mycoepoxydiene,¹⁴⁶ were isolated from a Diaporthe species, a marine fungus growing in submerged rotten leaves of the mangrove Kandelia candel (Fugong, China), and were cytotoxic against the KB and Raji cell lines.¹⁴⁷
Lyngbya majuscula (Alotau Bay, Papua New Guinea) yielded five lyngbyabellin analogues, lyngbyabellins E–I99–103, which were cytotoxic to NCI-H460 and neuro-2a cell lines.¹⁴⁸
Lyngbya semiplena (Wewak Bay, Papua New Guinea) was the source of four new depsipeptides , wewakpeptins A–D104–107, cytotoxic to brine shrimp and to the NCI-H460 and neuro-2a cell lines.¹⁴⁹Ankaraholides A108 and B109, glycosylated swinholides, were isolated from the cyanobacterium Geitlerinemasp. (Nosy Mitso-ankaraha Island, Madagascar) while swinholide A (previously isolated from the sponge Theonella swinhoei¹⁵⁰) was isolated from a cyanobacterium collected in the Fiji Islands. These two findings represent the first direct isolations of swinholides from cyanobacteria, establishing unequivocally that cyanobacteria can produce these metabolites (previously isolated from sponges but localised to heterotrophic bacteria). Ankaraholide A possessed comparable activity to swinholide A, inhibiting proliferation in NCI-H460, neuro-2a and MDA-MB-435 cell lines and inhibiting cytokinesis.¹⁵¹ From the filamentous mat-forming cyanobacterium Phormidiumsp. (Bise, Okinawa) the 2-alkylpyridine alkaloids phormidinines A110 and B111 were isolated.¹⁵²Majusculoic acid112, a brominated cyclopropyl fatty acid with modest antifungal activity, was isolated from a cyanobacterial mat assemblage (Sweetings Cay, Bahamas).¹⁵³ When the coastal cyanobacterium Synechococcussp. (Woods Hole Oceanographic Institution) was cultured under iron-limiting growth conditions, the synechobactins A–C113–115 were produced.¹⁵⁴
The new amphidinol AM7116, from the dinoflagellate Amphidinium klebsii obtained from a surface wash of a seaweed (Aburatsubo Bay, Japan), is sulfated, has a truncated polyhydroxyl chain, and has the shortest carbon backbone of any of the known amphidinols. AM7116 was active towards Aspergillus niger and also possessed haemolytic activity.¹⁵⁵ Five amphidinol analogues, amphidinols 9–13117–121 were isolated from Amphidinium carterae (Kauauroa, New Zealand). All were haemolytic against mouse erythrocytes, cytotoxic against P388 cells and antifungal towards Aspergillus niger to varying degrees. Those containing a sulfate ester at C-1, namely amphidinols 11–13119–121, had much reduced haemolytic and antifungal activities.¹⁵⁶Luteophanol D122, a weakly antibacterial polyhydroxy compound, was obtained from an Amphidinium species, isolated from the marine acoel flatworm Pseudaphanostoma luteocoloris (Okinawa).¹⁵⁷

The 26-membered macrolides , amphidinolides B4123 and B5 124, obtained from an Amphidinium species, isolated from a marine acoel flatworm Amphiscolopssp. (Ma'eda Cape, Okinawa), were potently cytotoxic against L1210 and KB cell lines.¹⁵⁸ From A. carterae (Hainan Island, China), an unsaturated glycoglycerolipid 125 was isolated,¹⁵⁹ while a glycosylated yessotoxin analogue, glycoyessotoxin A126 originated from Protoceratium reticulatum from a culture collection at the Centro Oceanográfico de Vigo.¹⁶⁰ Two further yessotoxin analogues, 127 and 128, trihydroxylated amides of 41a-homoyessotoxin and 9-methyl-41a-homoyessotoxin respectively, have been isolated from P. reticulatum, isolate CAWD40¹⁶¹ (Cawthron Institute Culture Collection).¹⁶²20-Methyl spirolide G129 was isolated concurrently from the microalga Alexandrium ostenfeldii and from the mussel Mytilus edulis (Skjer, Norway).¹⁶³ The polyether gymnocin-B130, isolated from the red tide dinoflagellate Karenia mikimotoi (Kushimoto Bay, Japan),¹⁶⁴ possesses the greatest number (15) of contiguous ether rings known to date.


The absolute configuration was not initially determined, as preparation of MTPA esters was unsuccessful, probably due to steric hindrance,¹⁶⁴ but the full absolute configuration was subsequently determined using a variety of approaches including conformational analysis of derivatives and chirality determination based on porphyrin–porphyrin circular dichroism exciton -coupled interactions over distance.¹⁶⁵ Gymnocin-B was cytotoxic to P388 cells, but only weakly ichthyotoxic.¹⁶⁴K. brevis (Wilson's 58 clone) contained a polyether compound, brevenal131, which competitively displaces brevetoxin from the binding site in rat brain synaptosomes and can antagonise toxic effects of brevetoxins in fish, but is itself non-toxic to fish.¹⁶⁶ Artificial cultures of Prorocentrum lima and P. belizeanum from strains obtained from the IEO (Vigo) produced new ester derivatives of okadaic acid: P. lima was the source of 132–134 and P. belizeanum135.¹⁶⁷ The polyketide prorocentrin136, an inhibitor of DLD-1 and RP-MI7951 cell lines, was isolated from P. lima (northern coast of Taiwan).¹⁶⁸Neosymbioimine137, in addition to the previously reported symbioimine138,¹⁶⁹ originated from a dinoflagellate Symbiodinium species separated from the acoel flatworm Amphiscolopssp. (Sesoko Island, Okinawa). Symbioimine138 had anti-resorptive activity,⁵⁷ and inhibited cyclooxygenase-2 (COX-2) activity.¹⁷⁰ An inseparable mixture of polyhydroxylated 61–66-membered macrolides , termed the zooxanthellamide Cs (ZAD-C1 to ZAD-C5) 139–143 was obtained from a Symbiodinium species (a sand beach in Hawaii).¹⁷¹

Detailed NMR spectroscopic analyses determined that the mixture consisted of five macrolactonised analogues of zooxanthellamide A, previously isolated from the same microalgae.¹⁷² The mixture displayed vasoconstrictive activity on rat blood vessels.¹⁷³ From the diatom Thalassiosira rotula (source not given) a series of C16 oxylipins 144–151 were isolated.
These are formally derived by the unprecedented enzymic oxidation of C16 fatty acids . In support of this, a network of oxygenase-mediated transformations that require C16 fatty acids as substrates was demonstrated.¹⁷⁴ A dihydroxysterol 152 was obtained from a phytoplankton Diacronema species (Sampayo, Portugal).¹⁷⁵ Aspernigrins A and B were originally isolated from a sponge-derived culture of Aspergillus niger.¹⁷⁶ The structure of aspernigrin B153 has now been revised¹⁷⁷ based on X-ray analysis of aspernigrin A reisolated from another source.¹⁷⁸ The first total synthesis of dragonamide154, a lipopeptide from Lyngbya majuscula,¹⁷⁹ was reported, and led to a reassignment of the configuration at the stereogenic centre in the alkyne -bearing fragment.¹⁸⁰
Total synthesis of a thiomarinol derivative isolated from Alteromonas rava originally separated from Darwinella rosacea¹⁸¹ has been reported.¹⁸² A short stereocontrolled sequence starting from p-methoxyphenol was employed in the total synthesis of yanuthones A–C and 22-deacylyanuthone A,¹⁸³ originally isolated from Aspergillus niger separated from an Aplidiumsp. ascidian.¹⁸⁴ An asymmetric synthesis of abyssomicin C, a polyketide from the actinomycete Verrucosisporasp. ,¹⁸⁵ has been reported,¹⁸⁶ as has the total synthesis of the heptapeptide cyclomarin C¹⁸⁷ from a Streptomyces species.¹⁸⁸ Syntheses of semiplenamide C,¹⁸⁹ a fatty acid amide isolated from Lyngbya semiplena¹⁹⁰ and pitipeptolide A,¹⁹¹ a cyclodepsipeptide originally isolated from L. majuscula have appeared.¹⁹² Tryptoquivaline J,¹⁹³ from Aspergillus fumigatus, has been isolated from a marine strain of the fungus for the first time.¹⁹⁴ The known microbial pigment metacycloprodigiosin¹⁹⁵ was isolated from the actinomycete Saccharopolysporasp. associated with the sponge Mycale plumose (Qingdao coast, China) and displayed significant cytotoxicity against five human cancer cell lines.¹⁹⁶ Bacillomycin D, first isolated from a terrestrial strain of Bacillus subtilis,¹⁹⁷ has been isolated from a strain separated from the sponge Stelletta validissima (Kuril Islands, Russia) and showed pH-dependent cytotoxic activity against Ehrlich carcinoma cells¹⁹⁸ and was also cytotoxic towards murine erythrocytes.¹⁹⁹ A marine-derived Aspergillus species yielded the polyketides (+)-epoxydon,²⁰⁰ (+)-epoxydon monoacetate,²⁰¹ gentisyl alcohol,²⁰² 3-chlorogentisyl alcohol²⁰² and methylhydroquinone²⁰³ as potent antibacterial agents against MRSA and multi-drug-resistant Staphylococcus aureus (MDRSA). The first four metabolites also exhibited significant radical scavenging activity against DPPH.²⁰⁴ Gymnodimine, originally isolated from a Gymnodinium species,²⁰⁵ sensitised the neuro-2a cell line to the apoptotic effects of another algal toxin , okadaic acid, raising the possibility that algal blooms involving the production of both of these classes of metabolites may generate greater cytotoxicity and pose more severe public health problems.²⁰⁶Biosynthesis of pentabromopseudilin,^207,208 originally isolated from Pseudomonas bromoutilis but also produced by other marine bacteria such as Alteromonas, has been studied. Feeding studies with A. luteoviolaceus demonstrated that the pyrrole ring is derived from proline.²⁰⁹ Biosynthetic studies on Symbiodiniumsp. , the dinoflagellate symbiont of the Caribbean gorgonian Pseudopterogorgia bipinnata, using ³H-labelled geranylgeranyl diphosphate indicated that this alga was capable of biosynthesising diterpenes previously ascribed²¹⁰ solely to the host coral.²¹¹ A fluorescent system has been described that profiles the connection between biosynthetic production and autotoxicity using complementary okadaic acid producing and nonproducing strains of the dinoflagellate genus Prorocentrum.²¹²

4 Green algae

Relatively few new secondary metabolites have been reported from green algae but the number still represents an increase from the 2004 review.²¹³Caulerpa brownii (Tasmania, Australia) occurs in branched and unbranched forms, each of which has yielded a number of novel diterpenoids . Unbranched material was the source of 155–159 and another diterpenoid reported previously as a synthetic compound.²¹⁴ The branched form yielded the terpenoid ester 160.²¹⁵
Avrainvillea nigricans (Portsmouth, Dominica), yielded the glycoglycerolipid avrainvilloside161 which contains the very rare 6-deoxy-6-aminoglucose moiety.²¹⁶ A halogenated biindole 162 and an apo-carotenone 163 were isolated from Chaetomorpha basiretorsa (Naozhou Island, China),²¹⁷ while clerosterol palmityl ester 164 was obtained from Codium fragile (Qingdao coast, China).²¹⁸ A solid-phase total synthesis of kahalalide A165, isolated from a Bryopsis species and its predator Elysia rufrescens,^219,220 established the stereochemistry of the methylbutyrate sidechain as (S).²²¹ The mild antimycobacterial activity of 165 and related analogues was also reported. The long-chain aldehyde (8Z,11Z,14Z)-8,11,14-heptadecatrienal, a component of the essential oil of Ulva pertusa,²²² has been synthesised.²²³

5 Brown algae

Terpenes and polyphenols continue to be the predominant classes of compounds reported from brown algae. The sargachromanols A–P166–181, meroterpenoids of the chromene class, were isolated from Sargassum siliquastrum (Jaeju Island, Korea).
The compounds all exhibited significant activity in the DPPH assay while compounds 172 and 180 were also inhibitors of butylcholine esterase.²²⁴ The known plastoquinones 182 and 183²²⁵ were isolated from S. micracanthum. Compound 182 displayed significant antioxidant activity while in contrast, 183 was potently active against human cytomegalovirus (HCMV) in vitro.²²⁶S. micracanthum (Toyama Bay, Japan) was the source of the strongly antioxidant plastoquinones 184–187, while compounds 185–187 also showed antiproliferative effects against 26-L5 cells.²²⁷Taonia atomaria (Serifos Island, Central Aegean Sea), was the source of the meroditerpenes atomarianones A188 and B189, cytotoxic agents against the NSCLC-N6 and A-549 cell lines.²²⁸(Z)-Sargaquinone190, the more saturated analogue 191, and the known sargaquinone²²⁹ were also isolated from T. atomaria, and were anti-inflammatory agents by inhibition of leukotriene biosynthesis.²³⁰

Five meroditerpenoids, 2β,3α-epitaondiol192, flabellinol193, flabellinone194, stypotriolaldehyde195stypohydroperoxide196 and the previously reported stypoldione²³¹ were isolated from Stypopodium flabelliforme (Long Island, Papua New Guinea) and were variously active in a range of bioassays including cytotoxicity, sodium channels as well as modulation of intracellular calcium concentrations.²³²
Dictyopteris divaricata (Qingdao, China) was the source of the bisnorsesquiterpenes 197–199 and the norsesquiterpene 200.²³³ The linear diterpenoids 201–205 were isolated from Bifurcaria bifurcata (Southern Brittany, France),²³⁴ and the absolute configuration of C-13 determined for 204 and 205, requiring revision of the stereochemistry of eleganediol206.²³⁵

Sargochromenol, originally isolated from Sargassum serratifolium,²³⁶ was shown to promote neurite outgrowth and survival in PC12D cells via distinct signalling pathways.²³⁷Phloroglucinol²³⁸ and the phloroglucinol derivatives eckstolonol,²³⁹ eckol,²⁴⁰ phlorofucofuroeckol A²⁴¹ and dieckol²⁴² were isolated from the brown alga Ecklonia stolonifera as hepatoprotective agents.²⁴³ (±)-Yahazunol²⁴⁴ and cyclozonarone²⁴⁵ were cytostatic and cytotoxic agents against several human tumour cell lines, while zonarol, zonarone and isozonarol²⁴⁶ also displayed cytotoxicity against various human tumour cell lines.²⁴⁷

6 Red algae

Reports of red algal metabolites have increased from the previous review but the field is still dominated by terpene and halogenated polyphenol chemistry. Five sulfur-containing polybromoindoles 207–211 were isolated from Laurencia brongniartii (Ken-Ting National Park, South Taiwan), of which 210 and 211 were active against P388 cells and 210 against HT-29 cells.²⁴⁸ From L. brongniartii (Kikai Island, Japan), five sulfur-containing polybrominated bisindoles 212–216 were isolated.²⁴⁹
A number of sesquiterpenes were isolated from L. tristicha (Naozhou Island, China). These included seven new compounds 217–223²⁵⁰ along with 10-hydroxyepiaplysin224, 10-hydroxyaplysin225 and 10-hydroxybromoepiaplysin226, all previously reported as synthetic intermediates^251,252 but now isolated as natural products.²⁵³
Compound 222 has a novel rearranged skeleton while compound 220 was previously reported as a synthetic racemate.²⁵⁴ Laurebiphenyl, a dimeric sesquiterpene reported previously from L. nidifica,²⁵⁵ was also isolated and exhibited moderate cytotoxicity against several human cancer cell lines.²⁵⁰ The cuparene sesquiterpenes 227–229, isolated from L. microcladia (Chios Island, North Aegean Sea), were cytotoxic against the NSCLC-N6 and A-549 cancer cell lines.²⁵⁶Laureperoxide230, 10-bromoisoaplysin231, isodebromolaurinterol232 and 10-hydroxyisolaurene233 are cuparene-derived sesquiterpenes isolated from L. okamurai (Nanji Island, China).²⁵⁷
Six diterpene compounds representing a new skeletal type, the dactylomelanes, were isolated from a Laurencia species (Paraíso Floral, Canary Islands). The compounds were the relatively unstable E-dactylohydroperoxide A234 and Z-dactylohydroperoxide A235, dactylohydroperoxide B236, the alcohol 237, dactylohydroperoxide C238 and puctatene239.²⁵⁸

L. luzonensis (Kudaka Island, Okinawa) was the source of the diterpene luzodiol240 and five snyderane sesquiterpenes 241–245.²⁵⁹ A brominated C15 polyketide allene chinzallene246, and a brominated diterpene 247 originated from another Laurencia species (Hatomisaki, Chinzei, Japan). The diterpene was also isolated from a collection made at Hachijo-jina Island, Tokyo.²⁶⁰ From Carpopeltis crispata (Johgashima Island, Japan) the ochtodene derivatives 248–252 were isolated.
All are regioisomers or stereoisomers of known compounds^261,262 from an Ochtodes species.²⁶³ Three new bromophenols 253–255 and two bromophenols known previously only as synthetic compounds,^264–267 came from Symphyocladia latiuscula (Dalian, China). All of the bromophenols were significant aldose reductase inhibitors.²⁶⁸ Three bromophenols coupled to pyroglutamic acid derivatives 256–258 and a bromophenol coupled with deoxyguanosine 259 were isolated from Rhodomela confervoides (Qingdao, China).
Compound 257 is a possible artifact since in aqueous methanol256 converts to 257 on standing.²⁶⁹ The polyhalogenated monoterpenes , plocoralides A–C260–262 have been isolated from the red alga Plocamium corallorhiza (Kalk Bay, South Africa).
Plocaralides B261 and C262, in addition to three other compounds previously isolated from a Plocamium species^270,271 and Aplysia californica,²⁷² displayed moderate activity against the human oesophageal cancer cell line WHCO1.²⁷³ From a Galaura species (Xisha Island, South China Sea), the cycloartane triterpenes galaxaurols A–E263–267 were isolated,²⁷⁴ while from Ptilonia magellanica (Straits of Magellan, Chile), three pyranosyl-like polyhalogenated metabolites, the pyranosylmagellanicus A–C268–270, and the putative biogenetic precursor 271 were discovered.²⁷⁵Corallinafuran272 and corallinaether273, a brominated dibenzofuran and diphenyl ether respectively, were isolated from crustose coralline red algae (Yomitan, Okinawa). Both were toxic to larvae of the scleractinian coral Pseudosiderastrea tayamai.²⁷⁶Callophycus serratus collected from several Fijian sites was the source of three antibacterial and antifungal diterpene-benzoate compounds, bromophycolides A274 and B275, and a non-halogenated compound 276. Bromophycolide A274 was also anti-HIV active and cytotoxic to several human tumour cell lines by specific induction of apoptosis.²⁷⁷ Synthesis of agardhilactone277, an eicosanoid isolated from the red alga Agardhiella subulata,²⁷⁸ has been reported and resulted in a revised structure.²⁷⁹


The isomeric conjugated trienes (5E,7E,9E,14Z,17Z)-eicosapentaenoic acid and (5Z,7E,9E,14Z,17Z)-eicosapentaneoic acid, originally isolated from Ptilota filicina,²⁸⁰ have been synthesised from methyl 5-oxopentanoate and found to be cytotoxic to DLD-1 cells by induction of apoptosis.²⁸¹ A stereoselective and concise total synthesis of (–)-isoprelaurefucin from Laurencia nipponica²⁸² has been completed²⁸³ and the total synthesis of (–)-isodomoic acid C, originally isolated from Chondria armata,²⁸⁴ has been reported.²⁸⁵ Free-radical chemistry was utilised in the total syntheses of several terpenoids with 7-membered heterocycles including laukarlaol²⁸⁶ from Laurencia karlae.²⁸⁷ 2,3,6-Tribromo-4,5-dihydroxybenzyl methyl ether,²⁸⁸ isolated from Symphyocladia latiuscula (Pusan, Korea), was active against wild type HSV-1, as well as APr HSV-1 and TK-HSV-1 and significantly delayed the appearance of lesions in infected mice without toxicity.²⁸⁹

7 Sponges

Sponges continue to attract considerable attention from both synthetic and natural product chemists. New ceramides and sphingolipids continue to be isolated from sponges, and the use of tandem MS to detect and determine the structure of these ceramides has been described.²⁹⁰Ircinia fasciculata (China) contained ircisulfamide278 and ircicerebroside279.²⁹¹Haliclonacerebroside280 was isolated from a Haliclona species and reported in 2004.²⁹² Vesparioside 281 was obtained from Spheciospongia vesparia (Bahamas),²⁹³ while an Amphimedon species (Japan) yielded the amphimelibiosides A–F282–287.²⁹⁴

The immunostimulatory glycosphingolipid damicoside 288 was isolated from Axinella damicornis (SW coast of Italy).²⁹⁵Rhizochalina incrustata (Seychelles Islands) contained rhizochalin A289.²⁹⁶ The glycolipid discoside 290, isolated as the peracetate derivative 291, was obtained from Discodermia dissoluta (Bahamas).²⁹⁷ A hybrid glycolipid –tetrahydroisoquinoline, oceanalin A292, obtained from an Australian Oceanapia species, was antifungal against Candida glabrata.²⁹⁸ A series of iminosugar-like N-cyclised sphingolipids, batzellasides A–C293–295, obtained from a Batzella species (Madagascar), were inhibitors of Raf kinase.²⁹⁹

A remarkably complex polysulfated glycolipid , axinelloside A296 with telomerase inhibitory activity, was isolated from Axinella infundibula (Japan).³⁰⁰ Two monoglycerides, homaxinolins A297 and B298, a phosphatidyl choline, homaxicholine A299 and a cytotoxic fatty acid 300 were obtained from a Korean Homaxinella species.³⁰¹

Untenone A³⁰² and plakevulin A,³⁰³ originally isolated from Plakortis species, have been synthesised.³⁰⁴ Syntheses of hachijodine A and B,³⁰⁵ originally isolated from Xestospongia and Amphimedon species respectively,³⁰⁶ and three irciniasulfonic acids,³⁰⁷ originally isolated from an Ircinia species,³⁰⁸ have been reported. Two groups have independently reported the synthesis^309,310 of pachastrissamine (jaspine B), originally isolated from a Pachastrissa species³¹¹ and subsequently from a Jaspis species.³¹² Caminoside A, from Caminus sphaeroconia,³¹³ has been synthesised.³¹⁴ A series of acetylenic fatty acid derivatives, strongylodiols D–J301–307, were obtained as non-racemic mixtures of enantiomers from an Okinawan Petrosia (Strongylophora).³¹⁵
Diplynes C and E, isolated from a Diplastrella species³¹⁶ have been synthesised asymmetrically allowing tentative assignment of the relative stereochemistries of the series.³¹⁷ The syntheses of (–)-siphonodiol and (–)-tetrahydrosiphonodiol, isolated from Siphonochalina truncata,^318,319 have been reported.³²⁰ Methyl peroxyacarnoates A and D, isolated from Acarnus cf. bergquistae³²¹ and bicladotylota³²² respectively, have been synthesised.³²³ Four branched chain polyketide-derived metabolites, lehualides A–D308–311, were isolated from a Plakortis species (Hawaii). Compounds 309 and 311 were cytotoxic to cancer cell lines.³²⁴Plakortis simplex (Norway), collected from 280 m by manned submersible, yielded two cycloperoxy-methyl esters 312 and 313 of which 313 was moderately cytotoxic.³²⁵
Two furanylidenic methyl esters, 314 and 315, from P. angulospiculatus (Brazil), were cytotoxic to brine shrimp.³²⁶Spongosoritin A316 was isolated from a Spongosorites species (Fiji).³²⁷
The reported structure of 316 is identical to that of 315 without relative stereochemistry specified. Although the optical rotations were similar, the reported NMR data show some significant differences; these compounds may be diastereomeric. Plakortis zyggompha (Martinique, Caribbean Sea) contained dinor-spiculoic acid317, and the weakly cytotoxic iso-318 and nor-spiculoic acids A319.³²⁸ From what appears to be the same collection of P. zyggompha, a series of cytotoxic cycloperoxides 320–326 were also isolated.
Plakortide Q320 was isolated as an acid while 321–326 were isolated as methyl esters prepared with TMSCHN₂.³²⁹ Interestingly, a sample of the crude extract of the sponge left standing in methanol for one year yielded the methyl esters directly; this finding may go some way to accounting for the prevalence of methyl esters as reported metabolites of Plakortis species. P. simplex (Bahamas) yielded two enone-containing branched chain metabolites, 327 and 328, and two anti-malarial cycloperoxides, 329 and 330.³³⁰
Unaware of the previous report, 329 was named plakortide Q, while 330 has previously been isolated from P. halichondroides without complete relative stereochemistry.³³¹ Methyl (2Z,6R,8R,9E)-3,6-epoxy-4,6,8-triethyl-2,4,9-dodecatrienoate, originally isolated from P. halichondrioides,¹²³ has been synthesised as a racemic mixture.³³² Three new aurantosides G–I331–333 have been isolated from Theonella swinhoei (Papua New Guinea).³³³Ircinia felix (Brazil) was the source of 4H-pyran-20-ol acetate334.³³⁴ An inhibitor of the protein-tyrosine phosphatase CDC25A, 335, was isolated from a Xestospongia species (Sulawesi, Indonesia), along with another polycyclic quinone 336.³³⁵ A Hyrtios species (Hawaii) yielded a trichloro metabolite poipuol337.³³⁶Psymberin338 (irciniastatin A), independently isolated from a Psammocinia species³³⁷ and Ircinia ramosa,³³⁸ has been synthesised establishing the identity and absolute stereochemistry, the relative stereochemistry at C-3 and confirming the originally proposed stereochemistry for psymberin.³³⁹

The relative and absolute stereochemistry of the C-1 to C-6 side chain was independently established by synthesis of a degradation product.³⁴⁰ Cylindramide, isolated from Halichondria cylindrata,³⁴¹ has been synthesised enantiomerically.³⁴² 13-Deoxytedanolide, isolated from Mycale adhaerans,³⁴³ binds to the 60S large ribosome subunit, thereby inhibiting protein synthesis.³⁴⁴ Two independent groups have shown that pateamine, originally isolated from Mycale hentscheli,³⁴⁵ inhibits eukaryotic protein synthesis initiation.^346,347 Potently bioactive peptides of non-ribosomal origin are a feature of sponge chemistry and continue to attract the attention of natural product and synthetic researchers alike. The moderately cytotoxic koshikamide A₂339 was isolated from the same Japanese Theonella species that yielded koshikamide A₁.³⁴⁸ A Haliclona species contained kendarimide A340. By synthesising a series of diastereoisomeric tetrapeptides corresponding to the region in 340 containing the 8-membered disulfide ring system it was concluded that the two contributing cysteine residues had an L configuration.³⁴⁹ The picomolar active cytotoxins polytheonamides A341 and B 342, originally isolated from Theonella swinhoei,^350,351 have been re-isolated from the same sponge, and from spectroscopic and chemical analyses the structures have been revised to those of the sulfoxide epimers .³⁵²
Halipeptin D343 has been isolated from Leiosella cf. arenifibrosa (Philippines),³⁵³ while halipeptins A³⁵⁴344 and D343 have been synthesised, confirming the presence of the thiazoline ring and establishing the relative stereochemistry of the side chain and absolute configuration . Intriguingly, the reported potent biological activity of halipeptins A and D was not confirmed by the synthesis, as the synthetic samples both showed weak cytotoxicity only.³⁵⁵ A Phakellia species (Chuuk, Micronesia) yielded the cytotoxic peptide phakellistatin 14345.³⁵⁶Dominicin346 was isolated from Eurypon laughlini (Dominica).³⁵⁷
Syntheses of phakellistatin 7 and the proline-rich phakellistatins 8 and 9, all isolated from Phakellia costata,³⁵⁸ have been reported.³⁵⁹ The synthetic phakellistatin 7 was spectroscopically identical to the natural compound while data for the phakellistatins 8 and 9 differed, again highlighting the difficulties associated with proline cis –trans isomerism . Also, all compounds were only weakly bioactive, in contrast to the potent activities originally reported.³⁵⁸ The determination of the stereochemistry of β-methoxytyrosine (β-MeOTyr) found in several sponge-derived cyclic peptides has received considerable attention. Callipeltin A347, originally isolated from a Callipelta species (New Caledonia), was reported without stereochemistry at the β-MeOTyr residue due to degradation during acid hydrolysis.³⁶⁰ All four possible stereoisomers of β-MeOTyr were synthesised and subjected to oxidative ozonolysis to yield the corresponding β-methoxyaspartates. Callipeltin A was then subjected to ozonolysis and acid hydrolysis. Marfey's analysis of the synthetic and callipeltin derived residues established the β-MeOTyr residue as (2R,3R).³⁶¹ The same general technique of hydrolysis and oxidation was used to determine a (2R,3R) configuration for the β-MeOTyr of papuamide B348,³⁶² isolated from a Theonella species.³⁶³ In a similar study, the stereochemistry of β-MeOTyr in papuamide A349, originally isolated from two species of Theonella,³⁶³ was determined.
In this case all four stereoisomers of β-MeOTyr were synthesised and incorporated into a tripeptide corresponding to the β-MeOTyr tripeptide sequence originally recovered from partial hydrolysis of 349. Comparison of the NMR spectra led to the assignment of this residue as (2R,3R) as above.³⁶⁴ Rather surprisingly, the β-MeOTyr of neamphamide A350, isolated from Neamphius huxleyi,³⁶⁵ was (2S,3R) in contrast to the above examples. In the same study, the remaining stereochemical uncertainties were determined: 4-amino-7-guanidino-2,3-dihydroxyheptanoic acid was assigned as (2R,3R,4S), and 3-hydroxy-2,4,6-trimethylheptanoic acid as (2R,3R,4R), establishing the full stereochemistry of the molecule.³⁶² Two epi-sulfoxides, neopetrosiamides A351 and B 352, found to inhibit amoeboid invasion by human tumour cells, were isolated from a Neopetrosia species (Papua New Guinea).³⁶⁶

Macrolides and related uncyclised PKS-derived molecules feature strongly in sponge metabolite chemistry. A series of potently cytotoxic 1,3-polyols, the mycapolyols A–F353–358, have been obtained from Mycale izuensis (South Japan).³⁶⁷ Another Japanese Mycale species yielded secomycalolide A359, an inhibitor of proteasome activity.³⁶⁸
Spongistatin 1, isolated from a Spongia species,³⁶⁹ was found to be an effective antifungal agent in vitro as well as in vivo in mice against Candida albicans and Cryptococcus neotormans.³⁷⁰ The structure of swinholide A, isolated from Theonella swinhoei,¹⁵⁰ bound to actin has been determined, revealing a similar binding site to the trioxazole sponge metabolites.³⁷¹ A synthesis of haterumalide NA, isolated from an Ircinia species,³⁷² has been reported.³⁷³ The original structure of clavosolide A, from Myriastra clavosa (Philippines),³⁷⁴ has been synthesised and on the basis of the very similar, but not identical spectroscopic data, it was proposed that the natural compound was a diastereomer of the synthetic compound with inversion of the stereogenic centres at the cyclopropyl rings.³⁷⁵ A pentabrominated diphenyl ether 360 has been isolated from Dysidea herbacea (Great Barrier Reef, Australia),³⁷⁶ and two other diphenyl ethers, 3,5-dibromo-2-(2′,4′-dibromophenoxy)phenol and 4,6-dibromo-2-(2′,4′-dibromophenoxy)phenol, previously isolated from Dysidea herbacea,³⁷⁷ are inhibitors of the Tie2 kinase involved in angiogenesis.³⁷⁸ A general synthetic strategy for the bastadins, macrocyclic brominated phenyl ethers typical of Ianthella basta,^379–382 has been reported with syntheses of bastadins 5, 10, 12, 16, 20 and 21 achieved.³⁸³ The importance of marine sponges as a source of novel alkaloids, in particular those with antitumour activity, has been recognized and reviewed.⁵⁶ A series of pyrrolidinones, dysidamides D–G361–364, epi-G365 and H366, and the related seco compounds 367 and 368 were isolated from Lamellodysidea herbacea (formerly Dysidea) (Red Sea).³⁸⁴
The relative stereochemistry of dysithiazolamide369, from a Dysidea species (Sulawesi, Indonesia), was determined by an extension of the J-based Murata method to include nitrogen substituents.³⁸⁵ The nematocidal agents, echinobetaines A370 and B 371, were isolated from a species of Echinodictyum (S. Australia), and syntheses reported.^386,387 In the same study, norzooanemonin372 was reported from a variety of Australian sponges.³⁸⁷ An adrenaline analogue, S1319 originally isolated from a Dysidea species,³⁸⁸ has been synthesised.³⁸⁹ An alkyl pyridinium dimer 373 with agonist activity against chemokine receptor CXCR3 was isolated from an unidentified sponge (Bahamas).³⁹⁰
The battle over determining the true structure of pyrinodemin A rages on.^12,13Alkene positional isomers have been synthesised and the NMR and MS data compared with data from the natural product, originally isolated from an Amphimedon species.³⁹¹ The closest match was found to be 374, but the authors concede that until more natural material is available for a complete spectral analysis, some doubt remains.³⁹² In a separate study the same alkene isomers were synthesised asymmetrically and compared by chiral HPLC analysis to a sample of the natural substance and were found to co-elute with a racemic mixture of 375.³⁹³Makaluvic acid C376 and the cytotoxic N-1-β-D-ribofuranosylmakaluvic acid C377 were both isolated from Strongylodesma aliwaliensis (E. coast of South Africa).³⁹⁴ A Latrunculia species (New Zealand) contained the cytotoxic dimeric discorhabdin W378.³⁹⁵
Zyzzya fuliginosa (E. Australia) yielded the moderately cytotoxic zyzzyanones B–D379–381.³⁹⁶ A series of bromoindole metabolites 382–385 were isolated from a Thorectandra species (Papua New Guinea).³⁹⁷ In the same study, two further related metabolites 386 and 387 were described from a Smenospongia species (Papua New Guinea).
A range of metabolites from both sponges displayed activity against Staphylococcus epidermis. A Psammoclemma species (New Caledonia) yielded the cytotoxic echinosulfonic acid D388.³⁹⁸Dendridine A389, a bis-indole alkaloid with antimicrobial activity, was obtained from a Dictyodendrilla species (Okinawa).³⁹⁹ (6R)-6″-Debromohamacanthin A390, (6R)-6′-debromohamacanthin A391, (+)-(S)-6″-debromohamacanthin B392 and dibromodeoxytopsentin393 were isolated from a Spongosorites species (Korea).⁴⁰⁰ In an independent study, (–)-(R)-6′-debromohamacanthin B394 was obtained from what appears to be the same Korean Spongosorites species.

Although the structure illustrated is the 6′-debromo derivative, it is referred to in the text of this study as the 6″-debromo derivative. Since the NMR solvents used in the two studies were different, a direct comparison of data cannot be made. In this second report, a series of related known metabolites were also isolated, several of which (deoxytopsentin, bromodeoxytopsentin and bromotopsentin) were inhibitors of bacterial sortase A.⁴⁰¹ Three moderately cytotoxic indole alkaloids, hyrtioerectines A–C395–397, were isolated from Hyrtios erectus (Red Sea, Egypt).⁴⁰² An Okinawan unidentified member of the Thorectidae family contained the antibacterial imidazole-β-carboline alkaloid gesashidine A398.⁴⁰³
Three new manzamine-type alkaloids 399–401 were isolated from an Acanthostrongylophora species (Indonesia) and reported in 2004. Compound 401 had antimalarial and antituberculosis activity.⁴⁰⁴ The synthesis of the (–) antipode of cis -dihydrohamacanthin B, originally isolated from Rhaphisia lacazei,⁴⁰⁵ was reported.⁴⁰⁶ From Axinella damicornis (Corsica), the alkylpyridinium-pyrrole alkaloid daminin402 was isolated and synthesised. While lacking cytotoxicity, the compound was found to inhibit Ca²⁺ uptake by neurons.⁴⁰⁷Petrosamine B403, an inhibitor of the Helicobacter pylori enzyme aspartyl semialdehyde dehydrogenase, was isolated from an Oceanapia species (Gulf of Carpentaria, Australia).⁴⁰⁸

Variolin B, originally isolated from Kirkpatrickia variolosa,⁴⁰⁹ and known to be a potent antitumour agent, inhibits cyclin dependent kinase (CDK) activity causing p53-independent apoptosis.⁴¹⁰ An enantiospecific synthesis of cribrostatin IV, isolated from Cribrochalina vasculum,⁴¹¹ has been achieved.⁴¹² Renieramycin G, originally isolated from Xestospongia caycedoi,⁴¹³ has been independently synthesised in both racemic⁴¹⁴ and enantiospecific⁴¹⁵ forms. The polyphenolic alkaloid dictyodendrin B, isolated from Dictyodendrilla verongiformis,⁴¹⁶ has been synthesised.⁴¹⁷Laughine404, a guanidine-bromopyrrole alkaloid , was isolated from the same Dominican sponge, Eurypon laughlini, as dominicin346 described earlier in this review.³⁵⁷Didiscus oxeata (Jamaica) was found to contain mukanadin D405.⁴¹⁸
Cyclooroidin, originally isolated from Agelas oroides,⁴¹⁹ has been synthesised.⁴²⁰ Enantiospecific syntheses of (S)-(–)-longamide B, (S)-(–)-hanishin and (S)-(–)-longamide B methyl ester have been reported establishing the configuration of the laevorotary enantiomers of these compounds.⁴²¹ Two ptilomycalin/crambescidin-type guanidine alkaloids, batzelladine J406 and crambescidic acid407 were obtained from Monanchora unguifera (Caribbean coast of Panama).⁴²² A total synthesis of crambescidin 431, originally isolated from a Monanchora species,⁴²³ has been achieved.⁴²⁴(–)-Crambidine408, originally isolated as the tetraacetate from Crambe crambe,⁴²⁵ has been synthesised establishing the relative stereochemistry.⁴²⁶ A bromotyrosine derived carbamic acid methyl ester 409 was isolated from Psammaplysilla purpurea (Southern India).⁴²⁷11-N-Methylmoloka'iamine410, 11-N-cyano-11-methylmoloka'iamine411 and kuchinoenamine412, all with antibacterial activity against the fish pathogen Aeromonas hydrophila, were obtained from a Hexadella species (Japan).⁴²⁸
A FOXO1a inhibition assay was used to isolate psammaplysenes A413 and B 414 from a Psammaplysilla species (Indian Ocean),⁴²⁹ while in a separate paper, the syntheses are reported.⁴³⁰Pseudoceratina purpurea (Gulf of Thailand) contained purpuroceratic acids A415 and B416.⁴³¹ The C-11 stereochemistries of fistularin-3417 (from Aplysina fistularis,⁴³²) and 11-epi-fistularin-3418 (from Agelas oroides⁴³³) were determined as (11S) and (11R) respectively. The variability of the C-11 stereochemistry of these, and related compounds from different organisms, was examined.⁴³⁴ Synthesis of the proposed structure of calafianin, originally isolated from Aplysina gerardogreeni,⁴³⁵ and the 6,6′ diastereomer 419 confirmed that 419 was the correct structure of the natural compound.⁴³⁶
A species of Erylus (S. Australia) was the source of N³,5′-cycloxanthosine420, the first naturally occurring cyclonucleoside, but already known as a synthetic product.⁴³⁷ Agelasine E, originally isolated from an Agelas species,⁴³⁸ has been synthesised.⁴³⁹ A synthesis of the proposed structure of epi-agelasine C, originally isolated from Agelas mauritiana,⁴⁴⁰ led to a structural revision of epi-agelasine C to 421 and of agelasine C, also isolated from an Agelas species,⁴⁴¹ to 422.⁴⁴² Four merosesquiterpenes, 20-O-acetyl-21-hydroxy-ent-isozonarol423, 20-O-acetylneoaverol424, ent-yahazunol425 and dysienone426 were obtained from two Dysidea species (Gulf of California).
Compounds 423 and 426 were cytotoxic.⁴⁴³Dysidea cf. cristagalli (New Zealand) yielded the previously described 20-O-acetyl-21-hydroxy-ent-isozonarol423, as well as 20-O-acetylneoaverol424 and the deacetylquinone analogue 427. Both new compounds inhibited superoxide production by human neutrophils.⁴⁴⁴Hatarumadienone428, a nor-puupehenone type meroterpenoid isolated from a Dysidea species (Okinawa), inhibited the division of fertilised sea urchin eggs.⁴⁴⁵
A racemic synthesis established that smenochromene D (Smenospongia species⁴⁴⁶) and likonide B (Hyatella species⁴⁴⁷) were enantiomers.⁴⁴⁸Strongylophorines 13–19429–435, isolated from Strongylophora strongylata (Okinawa), inhibited the maturation of starfish oocytes.⁴⁴⁹
Two polyprenylated hydroquinones 436 and 437, inhibitors of leucotriene production in porcine leukocytes, were isolated from Ircinia spinosula (Greece).⁴⁵⁰
Pelorol, originally isolated from Dactylospongia elegans⁴⁵¹ and Petrospongia metachromia,⁴⁵¹ was found to be a Src homology inositol-5-phosphatase (SHIP) activator, and was synthesised from (+)-sclareolide confirming the previous assignment of absolute stereochemistry.⁴⁵² Similarly, (–)-15-oxopuupehenol, originally isolated from a Hyrtios species,⁴⁵³ was synthesised from (–)-sclareol.⁴⁵⁴ A microwave-mediated Claisen rearrangement was used to synthesise panicein, originally isolated from Halichondria panicea.^455,456 Three bisabolene-type sesquiterpenoids 438–440 were reported from a Myrmekioderma species (Vanuatu).⁴⁵⁷ Two halogenated derivatives of helianane 441 and 442 were obtained from Spirastrella hartmani (Martinique).⁴⁵⁸
An ethanolic extract of Dysidea arenaria (New Caledonia) yielded an ethyl ether, 9-hydroxyfurodysinin-O-ethyl lactone 443, which the authors suggest was an artifact of the ethanolic extraction process .⁴⁵⁹ A Halichondria species (Okinawa) yielded a series of antimicrobial nitrogen-containing eudesmane sesquiterpenoids , halichonadins A–D444–447.⁴⁶⁰ A new curcuphenol analogue 448, several dimeric dicurcuphenols A–E449–453 and dicurcuphenol ether F454 were obtained from Didiscus aceratus (Papua New Guinea).

The dimers were synthesised from curcuphenol using the enzyme laccase, and the absolute stereochemistries of the biphenyl axes of 450 and 451 were determined using vibrational (IR) CD spectra.⁴⁶¹ Both (+)-(8S)-12-nordrimane-8,11-diacetate and (+)-11-hydroxy-12-nordrim-9-en-8-one, originally isolated from a Dysidea species,⁴⁶² have been synthesised.²⁴⁷ The isocopalane diterpenoid mycgranol 455 was isolated from Mycale aff. graveleyi (Kenya).⁴⁶³Axinyssa tethyoides (Okinawa) contained two 13-epi-neoverrucosanyl sulfates 456 and 457.⁴⁶⁴ Two rearranged spongane diterpenoids , omriolides A458 and B459 were obtained from Dictyodendrilla aff. retiara (Kenya).⁴⁶⁵
A re-isolation of amphilectene diterpenoids , originally isolated from a Caribbean Cribrochalina species,⁴⁶⁶ has led to a reassignment of the absolute stereochemistry of 460 and the relative stereochemistries of 461–463. A new compound 464 was also described in the same study.⁴⁶⁷ A re-isolation of microcionin-1465 from Fasciospongia cavernosa, but originally isolated from Microciona toxystila,⁴⁶⁸ established the relative stereochemistry with the unusual cis-fused ring A/B system.⁴⁶⁹
(–)-Marginatone, from Aplysilla glacialis,⁴⁷⁰ has been synthesised confirming the absolute stereochemical assignment.⁴⁷¹ Three partially cyclised sesterterpenoids 16-oxoluffariellolide466, 16-hydroxyluffariellolide467, and 468, all with phosphatase Cdc25B inhibitory activity, were isolated from a Thorectandra species (Papua New Guinea).⁴⁷²19-Methoxyscalarin469, from Hyrtios erectus (China), was reported in 2004.⁴⁷³
The hyrtiosins A–E470–474, scalarane type sesterterpenoids , were isolated from two separate collections of Hyrtios erecta (Hainan Island, China).⁴⁷⁴Hyrtios erecta (Maldives) yielded the cytotoxic sesterstatin 6475,⁴⁷⁵ while a collection of the same sponge from the Egyptian Red Sea yielded sesterstatin 7476.⁴⁷⁶

Ircinin-1, originally isolated from Ircinia oros,⁴⁷⁷ has been found to induce cell cycle arrest and apoptosis.⁴⁷⁸ Enantiospecific syntheses of luffolide, isolated from a Luffariella species,⁴⁷⁹ 16,25-dihydroxycheilantha-13(24),17-dien-19,25-olide and 25-hydroxycheilantha-13(24),15,17-trien-19,25-olide, isolated from an Ircinia species,⁴⁸⁰ have been reported.⁴⁸¹ A series of cytotoxic, highly degraded steroids , demethylincisterols A₁–A₄477–480 were isolated from a Homaxinella species (Korea). In the same study, four butoxy-derivatised sterols , homaxisterols A₁–A₄481–484, were also isolated from the same sponge.⁴⁸²Iotrochoto birotulata (Hainan Island, China) contained three 4-en-3-one sterols 485–487.⁴⁸³
Several polyhydroxylated sterols 488–491 were isolated from Lamellodysidea (Dysidea) herbacea (Red Sea), and 490 and 491 were active against Candida albicans.⁴⁸⁴ Another series of polyhydroxylated sterols , dysideasterols A–E492–496, were isolated from a Dysidea species (Hainan Island, China).⁴⁸⁵

Two moderately cytotoxic steroids 497 and 498 were obtained from a new species of Euryspongia (Vanuatu).⁴⁸⁶Stylisterols A–C499–501 and the unusual ring-fused cyclopropane-containing hatomasterol502 were obtained from a Stylissa species (Okinawa).⁴⁸⁷ The cytotoxic steroidal alkaloid plakinamine I503 was isolated from a Corticium species (Vanuatu).⁴⁸⁸
An unusual oxime containing steroid , (3E)-cholest-4-en-3,6-dione-3-oxime504 was isolated from Cinachyrella australiensis (China).⁴⁸⁹ Two steroidal glycosides , erylosides K505 and L 506 from Erylus lendenfeldi (Red Sea), were selectively active against a yeast strain defective in double stranded DNA repair. The absolute stereochemistry of eryloside A507, originally isolated from the same sponge, has also been established.⁴⁹⁰ A Jaspis species (Hainan Island, China) yielded 22,23-dihydrostellettin D508.⁴⁹¹ The cytotoxic triterpenoid sodwanone S509 was obtained from Axinella weltneri (Comoros Island, Indian Ocean).⁴⁹²

The sarasinosides J–M510–513, triterpene glycosides isolated from Melophlus sarassinorum (Sulawesi, Indonesia), were antimicrobial to B. subtilis and S. cerevisae.⁴⁹³Prianos osiros (Pohnpei, Micronesia) contained the unusual cytotoxic carotenoid 514.⁴⁹⁴

8 Coelenterates

There has been a noticeable increase in the number of new metabolites reported from coelenterates over the 2002–2005 period. The fatty acid ethyl ester 515 was isolated from the soft coral Nephthea hainansis (China), along with a sesquiterpene metabolite (see later).⁴⁹⁵ The polyacetylene carboxylic acids montiporic acids A and C, previously reported from Montipora digitata,^496,497 are potent feeding attractants of the coral predator mollusc Drupella cornus.⁴⁹⁸ (±)-1-Nonadecyloxy-2,3-propanediol, previously reported from the sponge Desmapsamma anchorata,⁴⁹⁹ was identified as a weakly cytotoxic constituent of Dendronephthya gigantea (Korea).⁵⁰⁰ Three sphingolipids 516–518 and a sterol (see later) were isolated from Lobophytumsp. (Indian Ocean).⁵⁰¹ A homologue of 518, 519, was obtained from a Lobophytum species (South China Sea).⁵⁰²
The dominant sphingolipid of Subergorgia suberosa (Indian Ocean) was 520,⁵⁰³ while confertamides A521 and B522 were identified in extracts of Sinularia conferta (China).⁵⁰⁴ A structurally-related sphingosine derivative,⁵⁰⁵ re-isolated from Sinularia crassa (Indian Ocean), exhibited anti-inflammatory activity.⁵⁰⁶Caucanolides A–F523–528 were isolated from Pseudopterogorgia bipinnata (Colombia),⁵⁰⁷ and while 523 and 526 exhibited mild activity towards Plasmodium falciparum, 523 also exhibited cytotoxicity towards a panel of tumour cell lines.

Meroditerpenoids chabrolonaphthoquinone B529, chabrolobenzoquinones E–H530–533 and chabrolohydroxybenzoquinones E–G534–536 were isolated as mildly cytotoxic constituents of Nephthea chabrolii (Taiwan).⁵⁰⁸
Oxygenated sesquiterpenes gibberodione537, peroxygibberol538 and sinugibberodiol539 were isolated from Sinularia gibberosa (Taiwan).⁵⁰⁹ Mild cytotoxicity was ascribed to 538. Bicyclic sesquiterpene 540 was reported from Nephthea hainansis (China).⁴⁹⁵ Chlorinated norsesquiterpene paralemnolin A541 and co-metabolites B542 and C543 were isolated from the soft coral Paralemnalia thyrsoides (Taiwan).⁵¹⁰
Seven sesquiterpenoid metabolites 544–550, comprising elemane, eudesmane and germacrane skeletal types, were reported as mildly antiplasmodial constituents of a Eunicea species (Caribbean).⁵¹¹
Laevinols A–H551–558, laevinone A559 and the known decalin 560 were isolated from Lemnalia laevis (Taiwan).⁵¹² The sesquiterpene alkaloid 561 was reported as a mildly cytotoxic metabolite of the gorgonian Subergorgia suberosa (China).⁵¹³Linderazulene562 and two new congeners 563 and 564 were isolated as mildly cytotoxic constituents of a deep-sea collection of the gorgonian Paramuriceasp. (Curaçao).⁵¹⁴
As noted in the 2004 review in this series,²¹³ three publications presenting new pterosin diterpene glycosides from Pseudopterogorgia elisabethae unwittingly led to duplication in structures and trivial names.^515–517 Communication with the authors of these studies has now led to the following clarification of trivial names associated with structures: pseudopterosin P565, Q566, R567, S568, 3′-O-acetyl-pseudopterosin Q569, 2′-O-acetyl-pseudopterosin Q570, pseudopterosin T571, U572, V573, 3′-O-acetyl-pseudopterosin U574, 2′-O-acetyl-pseudopterosin U575, pseudopterosin W576, X577 and Y578.⁵¹⁸ No structural revisions are proposed.
7-Hydroxyerogorgiaene and 7,8-dihydroxyerogorgiaene have been shown to be intermediates in the biosynthesis of the pseudopterosins.⁵¹⁹ Of ten diterpenes, the pacificins A–J579–588, isolated from Nephthea pacifica (Taiwan), only 581 and 586 were cytotoxic (mild).⁵²⁰
Microclavatin589 and the previously reported cembranolide capillolide,⁵²¹ were isolated as cytotoxic components of the soft coral Sinularia microclavata (China).⁵²²Sarcophytonsp. (China) was the source of sarcophytonolides A–D590–593.⁵²³ The relative configuration of leptolide594, isolated from Leptogorgia alba (Panama), was determined by X-ray analysis.⁵²⁴ A number of known diterpenes were also isolated in the same study from L. alba or L. rigida; combinations of CD spectra and X-ray analyses led to the determination of absolute configuration of pukalide aldehyde595, lophotoxin596, pukalide597, lopholide598 and 13α-acetoxypukalide599.

Sinularolides A–E600–604 were isolated from Sinularia gibberosa (China).⁵²⁵ Of these, 601–604 were mildly cytotoxic. 2-Hydroperoxysarcophine605 was reported as a natural product from the soft coral Lobophytum crassum (China).⁵²⁶ In addition to the known metabolites sinuleptolide606 and 5-epi-sinuleptolide607,⁵²⁷isocembranoid sinulochmodin B608, dimeric norcembranoid sinulochmodin A609, and yonarane diterpene sinulochmodin C610 were also reported from Sinularia lochmodes (Taiwan).⁵²⁸
The absolute configurations of 606 and 607 were determined and by comparison of [α]_D values, the absolute configurations of 608 and 609 were implied. The known cembranoid sinulariol D, previously obtained from a Sinularia species,⁵²⁹ was reported as mildly cytotoxic.⁵³⁰ Two separate reports have described the bioassay -directed fractionation of an extract from Xenia umbellata (Taiwan) leading to the mildly cytotoxic diterpenoids xenibellols A611 and B612⁵³¹ and umbellactal613.⁵³² The architecturally-impressive pentacyclic diterpene intricarene614 was reported from Pseudopterogorgia kallos (Colombia), with structural confirmation by X-ray analysis.⁵³³
A number of new examples of briarane diterpenoids were presented in separate reports from Briareumsp. (Japan). Violides Q–V615–620 and related metabolites 621–625 were reported from a Briareum species (Bonotsu, Kagoshima Prefecture),⁵³⁴ while a Briareum species (Amami Oshima, Kagoshima Prefecture) yielded briarlides I–R626–635.^535,536

Mild cytotoxicity was observed for 615, 616, 618 and 622. In a separate report, further investigation of Briareumsp. (Bonotsu) led to the isolation of briviolides A–D636–639, 12-O-acetylbriviolide D640, 9-deacetoxybriviolide D641, 4-acetoxybriviolide D642 and briviolides E–I643–648.^537,538

Mild cytotoxicity was observed for 637, 639–641 and 644. 8,17-Epoxybriarane diterpenes briarenol A649⁵³⁹ and briaranolides A–J650–659⁵⁴⁰ were isolated respectively from Taiwanese and Okinawan collections of Briareumsp. Renillins A–D660–663 were identified as feeding deterrent components of an extract of the sea pansy Renilla reniformis (North Carolina).⁵⁴¹ Chlorinated briaranes juncenolides F664 and G665 were isolated from Junceella juncea (Taiwan),⁵⁴² while Junceella fragilis (South China Sea) yielded junceellonoids C–E666–668.⁵⁴³


The absolute configuration of the eunicellin-class diterpenoid 11-acetoxy-4-deoxyasbestinin669, originally isolated from Briareum asbestinum,⁵⁴⁴ has been determined by stereoselective total synthesis.⁵⁴⁵ New eunicellins klyxumines A670 and B671 and epoxycladines A–D672–675 were reported from specimens of Klyxum flaccidum and Cladiella kashmani (Kenya).⁵⁴⁶Vigulariol676, previously known as a reaction intermediate in the stereoselective synthesis of the sclerophytins,⁵⁴⁷ was isolated from the sea pen Vigularia juncea (Taiwan).⁵⁴⁸
Australins A–D677–680 were isolated from Cladiella australis (Taiwan), but only 678 was mildly cytotoxic.⁵⁴⁹ Xenicane diterpenes 681–688 were reported from Xenia blumi (Taiwan)⁵⁵⁰ while Xenia florida (Taiwan) was the source of xeniolactones A–C689–691.⁵⁵¹ Mild cytotoxicity was observed for 681–684, 686, 687 and 689. The nor-xenicane metabolite xenibellal692 was reported as a mildly cytotoxic component of Xenia umbellata (Taiwan).⁵⁵²


Confertdiate693 is a tetracyclic diterpenoid isolated from Sinularia conferta (China),⁵⁰⁴ while sterol 694 was reported from a Lobophytum species (India).⁵⁰¹ 3-Oxo-sterols 695–701 were reported as mildly cytotoxic metabolites of Anthomastus bathyproctus (Antarctica)⁵⁵³ and 702 and 703 were isolated from Nephthea bayeri (China),⁵⁵⁴ while the 19-acetoxy-sterols 704 and 705 were reported from a soft coral Sinularia species (China).⁵⁵⁵

The polyoxygenated sterols hippuristerones J–L706–708, the hippuristerols E709 and F710 and the cyclopropyl-containing sterol 711 were isolated from Isis hippuris (Taiwan),⁵⁵⁶ while Sinularia dissecta (China) was the source of 712–717.⁵⁵⁷

Rare examples of cholesterol-3-formate esters 718 and 719 and A-nor sterols 720–722 were reported from Dendronephthyasp. (China).⁵⁵⁸ The hemiketal steroid cladiellin A723, isolated from Cladiellasp. (China), along with two dehydration products were found to have radical scavenging properties.⁵⁵⁹ The 24-ketal steroids suberoretisteroids A–E724–728 were reported from Subergorgia reticulata (China).⁵⁶⁰ Structure elucidation, which included X-ray analysis of 724,⁵⁶¹ necessitated a structural revision of 729 previously reported from Gorgonella umbraculum.⁵⁶² Similar conclusions were made by another group working on the same species of gorgonian from the same locale.⁵⁶³ Their studies led to the determination of absolute configuration of 724 (which they named reticulatin) and 729. In addition, this study also reported the structure of reticulatic acid730.
In addition to a number of known congeners , eleven new examples of hippuristanol sterols , 731–741, were reported from Isis hippuris (Taiwan).⁵⁶⁴ The absolute configuration of the known sterol 742⁵⁶⁵ was determined on biogenetic grounds and imputed to all but 741 of the compounds reported.
Steroidal glycosides 743 and 744 were obtained from Cladiellasp. (China),⁵⁶⁶ while 745–748 were isolated from Junceella juncea (China).⁵⁶⁷ Gorgosterol derivatives previously isolated from Eunicea laciniata⁵⁶⁸ and Plexaurella grisea,⁵⁶⁹ were reported to be agonists of Liver X receptors.⁵⁷⁰ A sea anemone of the order Actinaria was the source of diterpenoids actiniarins A–C749–751, moderate inhibitors of recombinant human cdc25B phosphatase.⁵⁷¹ The usual class of natural products isolated from anemones, peptides and protein toxins , have been reviewed,⁵⁷² and new examples reported. Antheopsis maculata (Japan) was the source of crab toxic peptides Am I–III,⁵⁷³ while acrorhagins I and II are 50 and 44 residue peptides respectively isolated from Actinia equina (Japan).⁵⁷⁴ Cytolytic toxins Or–A and Or–G were isolated from Oulactis orientalis (Japan) and found to form ion channels in bilayer lipid membranes.⁵⁷⁵ Cangitoxin, a 4958 Da peptide isolated from Bunodosoma cangicum (Brazil), acts on sodium channels.⁵⁷⁶

9 Bryozoans

Remarkably, there have been no reports of new bryozoan chemistry. Some analogues of amathamide A (originally obtained from Amathia wilsoni⁵⁷⁷) have been prepared and their antimicrobial activities studied.⁵⁷⁸

10 Molluscs

The number of new metabolites reported annually from molluscs has been somewhat cyclical over the 2002–2005 period, with a modest increase reported in 2005. A range of minor nonmethylene-interrupted di-, tri- and tetraenoic fatty acids were identified in extracts of the gonads of limpets Cellana grata and Collisella dorsuosa (Japan).⁵⁷⁹Turbostatins 1–4752–755 were isolated as cytotoxic components of the Asian topshell snail Turbo stenogyrus (Taiwan).⁵⁸⁰
20-Methyl spirolide G129 was identified by MS/MS analysis of extracts of Mytilus edulis (Norway).¹⁶³ Further biological testing of the hexacyclic alkaloid lamellarin D, first reported from Lamellariasp. in 1985⁵⁸¹ has identified lamellarin D to be a pro-apoptotic agent which remains cytotoxic in multidrug resistant cell lines.⁵⁸² Molluscs of the order Sacoglossa are a renowned source of polypropionate-derived metabolites.⁵⁸³ Pyrone 756, and the possibly artefactual peroxy derivative 757, were isolated from Placobranchus ocellatus (India).⁵⁸⁴ The bicyclo[4.2.0]octane core of 756 is analogous to that contained in the related metabolites elysiapyrones A758 and B759 reported from Elysia diomedea.⁵⁸⁵
The proposed biogenesis of the bicyclic core is via an 8π–6π electrocyclic cascade. A biomimetic synthesis of elysiapyrones A and B utilised such a pathway⁵⁸⁶ and a biomimetic synthesis of (±)-9,10-deoxytridachione based upon an electrocyclisation step has also been reported.⁵⁸⁷ 9,10-Deoxytridachione also reacts under triplet excited state sensitisation to afford photodeoxytridachione⁵⁸³ which has the ecological implications of polypropionates acting as natural sunscreening agents.⁵⁸⁸ Related pyrone, cyercene A,⁵⁸⁹ also undergoes photoisomerisation to yield alkene isomers and hydroperoxides which have been reported previously as natural products.⁵⁹⁰ The structure proposed for tridachiahydropyrone760, isolated from Tridachia crispata,⁵⁹¹ has been synthesised but the spectroscopic data observed did not match that reported for the natural product. A revision of the structure of the natural product is required.⁵⁹² The absolute configuration of the trans-decalin 761 isolated from the limpet Trimusculus reticulatus⁵⁹³ has been determined by stereoselective synthesis .⁵⁹⁴Carotenoids 762–764 were reported from the oyster Crassostrea gigas (Japan)⁵⁹⁵ while a 4265 Da defensin antimicrobial peptide was isolated from the American oyster Crassostrea virginica.⁵⁹⁶
Two conotoxins, µ-conotoxins SIIIA and KIIIA, were characterised by cDNA analysis of Conus striatus and C. kinoshitai (Pacific) and subsequent solid-phase synthesis.⁵⁹⁷ A more classical approach led to the isolation of peptide de7a from the venom of C. delessertii (Mexico),⁵⁹⁸ and rg11a from C. regius (Brazil).⁵⁹⁹ The biological activities of both peptides have yet to be characterised. The solution structure of δ-Am2766, a highly hydrophobic conotoxin isolated from C. amadis⁶⁰⁰ has been studied by 3D NMR spectroscopy.⁶⁰¹ Two reviews cover the chemical ecology of New Zealand opisthobranch molluscs,⁶⁰² and the role played in ink secretions from the sea hare Aplysia californica.⁶⁰³ Sesquiterpenes 765–767, in addition to a number of known derivatives, were isolated from A. dactylomela (Canary Islands).⁶⁰⁴In vitro antitumour evaluation supported the hypothesis that acetylation leads to a decrease in metabolite toxicity. Three C15-halogenated compounds 768–770 were isolated from A. dactylomela (China).⁶⁰⁵ The structure and absolute configuration of 768 was established and it was concluded that 769 and 770 were enantiomers of previously reported natural products⁶⁰⁶ of defined absolute configuration .⁶⁰⁷
This study also necessitated the stereochemical revision of (3E)-epi-pinnatifidenyne, previously reported from Laurencia obtusa,⁶⁰⁸ to ent-768. The related metabolite (3Z)-bromofucin771 was isolated from extracts of Aplysia parvula (South Africa).⁶⁰⁹ Acetates of laurinterol 772 and debromolaurinterol773, previously known as semi-synthetic compounds, were reported as mildly bioactive natural products from Aplysia kurodai (Japan).⁶¹⁰Bursatella leachii (Thailand) was the source of the known metabolite hectochlorin774, the deacetyl analogue 775 and the structurally-unrelated 776.⁶¹¹ Both 774 and 775 were potently cytotoxic. Degraded sterols aplykurodinone-1777 and -2778 were isolated from skin extracts of the sea hare Syphonota geographica (Greece).⁶¹²
The stereochemical assignment of (+)-aurilol779, isolated from the sea hare Dolabella auricularia,⁶¹³ has been achieved via stereoselective total synthesis.⁶¹⁴ Analogues of dolastatin 11, also originally isolated from D. auricularia,⁶¹⁵ have been synthesised and evaluated for antitumour activity and stimulatory effects on the polymerisation of actin.⁶¹⁶ Two groups have reported the stereoselective synthesis of the nor-sesquiterpene (+)-austrodoral780, originally isolated from the Antarctic nudibranch Austrodoris kerguelenensis,⁶¹⁷ starting from either (–)-sclareol⁶¹⁸ or (+)-sclareolide.⁶¹⁹ Furanosesquiterpenes alcohols pelseneeriols-1781 and -2782 were isolated from the mantle of the nudibranch Doriopsilla pelseneeri (Portugal).⁴⁶⁹ Syntheses of 5-methyl-2-((2E,6E)-3,7,11-trimethyl-2,6-dodecadien-9-onyl)benzo-1,4-quinone and the hydroquinone, isolated from the South African nudibranch Leminda millecra,⁶²⁰ have been reported.⁶²¹ The absolute configurations of nudibranch-derived diterpenes norrisolide783,⁶²² isolated from Chromodoris norrisi,⁶²³ and dorisenone C784⁶²⁴ from C. obsoleta,⁶²⁵ have been determined by stereoselective syntheses.
The stereoselective synthesis of (–)-jorumycin, isolated from the Pacific nudibranch Jorunna funebris,⁶²⁶ has confirmed the absolute configuration of the cytotoxic tetrahydroisoquinoline alkaloid and also provided related structures for preliminary examination of structure–activity relationships.⁴¹⁵

11 Tunicates (ascidians)

The number of new metabolites reported annually from ascidians has been steadily declining over the 2002–2005 period. A didemnid ascidian (Okinawa) was the source of biselides A–E785–789,⁶²⁷ of which 785 and 787 were modestly cytotoxic towards a panel of tumour cell lines.
The absolute configuration of bistramide C790, isolated from Lissoclinum bistratum,⁶²⁸ has been determined by computational analysis⁶²⁹ and total synthesis.⁶³⁰ Two long chain polyacetoxy acyl amino acids, sagittamides A791 and B792 were isolated from an unidentified ascidian (Pohnpei).⁶³¹Aplidium aff. densum (Oman) was the source of the meroterpenes methoxyconidiol793 and didehydroconicol794,⁶³² while the ubiquinone derivatives glabruquinones A795 and B796 were reported from Aplidium glabrum (Far East).⁶³³

The structures of 795 and 796 were confirmed by synthesis and 795 was found to exhibit in vitro cancer preventive activity in a tumour cell transformation assay. The structures of the demethoxy diprenylquinone analogues verapliquinones A and B, isolated from Brittany specimens of Aplidiumsp. ,⁶³⁴ have also been confirmed by synthesis.⁴⁵⁶Extracts of Aplidium conicum (Mediterranean) yielded 1,1-dioxo-1,4-thiazine containing aplidinones A–C797–799⁶³⁵ and thiaplidiaquinones A800 and B801.⁶³⁶
Bioassay evaluation of 800 and 801 demonstrated that the compounds had entered the cells, and induced the intracellular production of reactive oxygen species leading to disruption of mitochondrial potential and cell death by apoptosis. Perspicamides A802 and B803 are quinolinecarboxylic acid derivatives isolated from Botrylloides perspicum (Australia).⁶³⁷Synoicum macroglossum (India) was the source of a modestly α-glucosidase inhibitory alkaloid , tiruchanduramine804. The structure was confirmed by synthesis.⁶³⁸ A full account of the structure elucidation of lissoclibadin 1⁶³⁹ from Lissoclinum cf. badium (Indonesia) has been reported, along with two new congeners , lissoclibadins 2805 and 3806.⁶⁴⁰
All three metabolites exhibited varying degrees of cytotoxicity and antibiotic properties. Investigations of the chemistry of colour morphs of a Cystodytes species (Mediterranean) led to the isolation of deacetylshermilamine B807.⁵⁶¹ In addition to a number of known congeners , new lamellarin alkaloids 808–811 were isolated from Didemnum obscurum (India).⁶⁴¹ Potent cytotoxicity towards colorectal tumour cells was observed. An unidentified ascidian of the family Polycitoridae (Flores, Indonesia) contained two tricyclic alkaloids, polycitorols A812 and B813, closely related to the known cylindricines,⁶⁴² together with the known compound lepadiformine.^643,644
Two studies have reported that the biosynthetic genes for production of the patellamide cyclic peptides reside within Prochloronsp. , the cyanobacterial symbiont of Lissoclinum patella.^645,646 The structures of cyclic peptides bistratamides F–I, isolated from Lissoclinum bistratum,⁶⁴⁷ have been confirmed by total synthesis,^648,649 as were the structures of the Didemnum molle metabolites⁶⁵⁰ didmolamides A and B.⁶⁵¹ The antimalarial activity of cyclic peptides ulithiacyclamide and patellamides A–C has been reported.⁶⁵² The absolute stereochemistry of (+)-pseudodistomin D814, reported in 1997 from Pseudodistoma megalarva,⁶⁵³ has been established by total synthesis.⁶⁵⁴
Stereoselective synthesis of the Nephteis fasicularismetabolite ⁶⁵⁵ (–)-fasicularin has been reported.⁶⁵⁶ The original isolation report of fasicularin noted differential activity towards DNA repair-deficient yeast mutants. The DNA damaging ability of a racemic preparation of the alkaloid has now been studied in depth.⁶⁵⁷ The structurally related quinolizidine and decahydroquinoline alkaloids (–)-pictamine⁶⁵⁸ and (–)-lepadin B⁶⁵⁹ block neuronal nicotinic receptors.⁶⁶⁰ Ningalin D, an MDR reversing cytotoxic alkaloid originally reported from Didemnumsp. (Australia),⁶⁶¹ has been synthesised and structure–activity relationships studied.⁶⁶² The cyclodepsipeptide aplidine continues through clinical trials⁶⁶³ with a recent report detailing structures of human liver microsome induced metabolism.⁶⁶⁴ The in vivo activity profile of ET-743 has been summarised⁶⁶⁵ and the anti-inflammatory properties reported.⁶⁶⁶ The solution structure of vanabin2, a vanadium binding protein from Ascidia sydneiensis samea, has been studied by NMR spectroscopy.⁶⁶⁷

12 Echinoderms

The number of new metabolites reported annually from echinoderms has remained relatively constant over the 2002–2005 period. While echinoderms are a well documented source of biologically active saponins and glycolipids ,^16,668 they also represent an important food source.¹⁵ The naphthoquinone metabolites echinamines A815 and B816 were isolated from the sea urchin Scaphechinus mirabilis (Japan Sea), and the structures confirmed by semi-synthesis from known urchin quinones .⁶⁶⁸ Radical scavenging properties were observed for both compounds. Ceramide lipids 817–819 were isolated from the starfish Distolasterias nipon (East Sea, Korea).⁶⁶⁹
The sea cucumber Stichopus japonicus was the source of five glycolipid molecular species SJC-1 820, SJC-2 821, SJC-3 822, SJC-4 823 and SJC-5 824.⁶⁷⁰Linckiacerebroside A825 was identified as a new glycolipid from the starfish Linckia laevigata (Japan).⁶⁷¹
Further attempts at purification of the components of the glucocerebroside molecular species HLC-2, previously reported from the sea cucumber Holothuria leucospilota,⁶⁷² led to the characterisation of 826.⁶⁷³ The ante-iso type side chain configuration of 826 was determined by synthesis.⁶⁷⁴ A ganglioside molecular species LLG-5 827, containing an unusual trisialosyl moiety, was isolated from the Japanese starfish Linckia laevigata.⁶⁷⁵ In addition to a number of known compounds, the isopropylidenedioxy sterol 828 was reported from the starfish Asterina pectinifera (China).⁶⁷⁶ Further investigation of the constituents of the Far-Eastern starfish Ctenodiscus crispatus led to the isolation of 829 as a mixture of C-24 and C-25 stereoisomers , together with 830 and 831. The side chain stereochemistry of the known structurally-related sterol 832⁶⁷⁷ was defined as (24R,25R).⁶⁷⁸
The cyclopropane-containing hydroxysteroid phrygiasterol833 and steroid glycoside phrygioside B834 were isolated from the Far-Eastern starfish Hippasteria phrygiana.⁶⁷⁹ Mild cytotoxicity towards, and apoptotic induction of, Ehrlich carcinoma cells was observed. Two β-D-xylosides, minutosides A835 and B836, were reported from the starfish Anasterias minuta (Patagonia).⁶⁸⁰Minutoside B836 bears an unusual amidohypotaurine sidechain. Both 835 and 836 were modestly antifungal. Studies of two species of Far-Eastern starfishes, Henricia aspera and H. tumida led to identification of a number of new polyhydroxyl steroids and glycosides .⁶⁸¹Henricia aspera was the source of asperosides A837 and B838, H. tumida the source of 839 and 840, while tumidosides A841 and B842 were isolated from both species.
All six metabolites exhibited moderate cytostatic activity towards sea urchin eggs. Bioassay -directed fractionation of extracts from the starfish Certonardoa semiregularis (Korea) led to the characterisation of the moderately cytotoxic saponin certonardoside P₂ 843, and inactive certonardoside I₃ 844.⁶⁸² The isolation of the bioactive asterosaponins 845–850 from the cushion star Culcita novaeguineae (China) has been detailed in three separate reports.^683–685 The triterpene nobilisidenols A851 and 852 were isolated from Holothuria nobilis (China).⁶⁸⁶

Triterpene glycosides, holothurins B₂ 853, B₃ 854 and B₄ 855, were reported from a collection of Holothuria polii (Bay of Naples).⁶⁸⁷ Six triterpene tetraosides, intercedensides D–I856–861, were isolated as cytotoxic constituents of the sea cucumber Mensamaria intercedens (China).⁶⁸⁸ This study also concluded that the sidechain stereochemistry of intercedenside A862⁶⁸⁹ should be corrected to (22Z). Bioassay -directed fractionation of an extract of the sea cucumber Pentacta quadrangularis (China) yielded the dual anti-angiogenic and anti-proliferative saponin, philinopside A863.⁶⁹⁰

However, no spectroscopic data were reported to support the structure shown. The sea cucumber Australostichopus mollis (New Zealand) was the source of the monosulfated triterpene glycosides mollisosides A864, B₁ 865 and B₂ 866,⁶⁹¹ while Stichopus parvimensis (Baja California), yielded the oligoglycosides parvimosides A867 and B868.⁶⁹² A smooth muscle-relaxing hexadecapeptide was characterised from the starfish Asterina pectinifera.⁶⁹³

13 Miscellaneous

Methoxylated polybrominated biphenyls, including the new analogue 869, have been identified as bioaccumulated natural products in a number of marine mammals.^694,695 A further range of toxic peptides have been identified in skin secretions of the soapfish Grammistes sexlineatus.⁶⁹⁶ The hydroid Campanulariasp. (New Zealand) was the source of the guanidine 870,⁶⁹⁷ while a Chinese collection of the annelid Arenicola cristata led to the isolation of the cytotoxic sulfated sterol arenicolsterol A871.⁶⁹⁸ The modestly cytotoxic cymodienol872 and cymodiene873 were isolated from the sea grass Cymodocea nodosa (coastal areas of central Greece).⁶⁹⁹ In two separate studies, the mangrove plant Bruguiera gymnorrhiza (China) yielded phenols 874–878⁷⁰⁰ and diterpenes 879–881.⁷⁰¹


The phenol 876 was moderately active towards a range of microorganisms, while the diterpene 881 was mildly cytotoxic towards mouse fibroblast cells. A second species of Chinese mangrove plant, Bruguiera sexangula var. rhynchopetala, was the source of the diterpenes 882–884 and the disulfide quinone 885.⁷⁰²Bruguiera gymnorrhiza (China) yielded related diterpenes 886–889.⁷⁰³ Mild cytotoxicity was observed for 888 and 889.

14 Conclusions

In reviewing the literature for 2001, the observation was made that the rate of increase in publications of new compounds compared with 1965–2000 might have been easing.⁷⁰⁴ The publication rate for each of the years 2001–2005 has varied somewhat, but at the end of this period, using numbers extracted from MarinLit,⁶⁸ the steady arithmetic increase observable since 1965 continues (see Fig. 1).

Fig. 1 Numbers of marine natural products for the period 1965–2005.

The geographic origins and the phyla sampled for 2001–2005 were examined to establish the differences, if any, compared with the sampling over the previous 36 years. These 2001–2005 data are shown in Fig. 2 and 3 as percentages of the totals for 1965–2005.

Fig. 2 Citations for source regions for the period 2001–2005 as a percentage of the totals for 1965–2005.

Fig. 3 Citations for source phyla for the period 2001–2005 as a percentage of the totals for 1965–2005.

Although the geographical descriptors used in MarinLit are not precise, the large increase from the China Sea as a source area is unmistakable. While the absolute numbers of samples are less, there has also been a notable increase in sampling from the North Sea, the Baltic and Russian territories.

Few people would be surprised by the observation that 45% of the accumulated literature on marine microorganisms has been published since 2000. Other phyla show (relatively) increased interest also. These “traditional” phyla, such as Porifera, Chordata and Coelenterata, are significant as the absolute numbers for 1965–2000 reported for these phyla are much larger than those for microorganisms. It is pertinent to note that some 40% of the work for 2001–2005 on coelenterates has been sourced from the China Sea.

Analysis of the data for 2001–2005 period against the accumulated records from 1965 onwards suggests that the study of marine natural products is thriving, attracting new research groupings and making rapid progress in exploring alternative source phyla and geographical areas.

15 References

1. J. W. Blunt, B. R. Copp, M. H. G. Munro, P. T. Northcote and M. R. Prinsep, Nat. Prod. Rep., 2005, 22, 15.
2. C.-Y. Wang, M.-Y. Geng and H.-S. Guan, Chin. J. New Drugs, 2005, 14, 278.
3. A. M. S. Mayer and M. T. Hamann, Comp. Biochem. Physiol., Part C: Toxicol. Pharmacol., 2005, 140, 265.
4. M. S. Butler, Nat. Prod. Rep., 2005, 22, 162.
5. G. M. Cragg and D. J. Newman, Pure Appl. Chem., 2005, 77, 1923.
6. G. M. Cragg and D. J. Newman, Pure Appl. Chem., 2005, 77, 7.
7. X.-H. Yan and Y.-W. Guo, Chin. J. Nat. Med., 2005, 3, 65.
8. S. Singh, B. N. Kate and U. C. Banerjee, Crit. Rev. Biotechnol., 2005, 25, 73.
9. T. Okino, Kaiyo Seibutsu Seibun no Riyo, 2005, 47.
10. S. Tsukamoto, Kaiyo Seibutsu Seibun no Riyo, 2005, 60.
11. D. Sipkema, M. C. R. Franssen, R. Osinga, J. Tramper and R. H. Wijffels, Mar. Biotechnol., 2005, 7, 142.
12. K. Iguchi, Kaiyo Seibutsu Seibun no Riyo, 2005, 97.
13. S. Fukuzawa, Kaiyo Seibutsu Seibun no Riyo, 2005, 132.
14. T. Miyamoto, Kaiyo Seibutsu Seibun no Riyo, 2005, 145.
15. M. S. Kelly, Prog. Mol. Subcell. Biol., 2005, 39, 139.
16. Y. Yokota, Prog. Mol. Subcell. Biol., 2005, 39, 251.
17. M. Ishibashi, Kaiyo Seibutsu Seibun no Riyo, 2005, 159.
18. T. J. Heckrodt and J. Mulzer, Top. Curr. Chem., 2005, 244, 1.
19. E. Zubia, M. J. Ortega and J. Salva, Mini–Rev. Org. Chem., 2005, 2, 389.
20. J. Sun, H. Lin, S. Li, G. Liu, C. Zhang and H. Zhang, Zhongcaoyao, 2005, 36, 609.
21. H. N. Kamel and M. Slattery, Pharm. Biol., 2005, 43, 253.
22. T. L. Simmons, E. Andrianasolo, K. McPhail, P. Flatt and W. H. Gerwick, Mol. Cancer Ther., 2005, 4, 333.
23. M.-L. Bourguet-Kondracki and J. M. Kornprobst, Adv. Biochem. Eng. Biotechnol., 2005, 97, 105.
24. Y. Nogata, Kaiyo Seibutsu Seibun no Riyo, 2005, 290.
25. D. Alonso, A. Castro and A. Martinez, Expert Opin. Ther. Pat., 2005, 15, 1377.
26. L. Gomez-Paloma, M. C. Monti, S. Terracciano, A. Casapullo and R. Riccio, Curr. Org. Chem., 2005, 9, 1419.
27. R. A. Keyzers and M. T. Davies-Coleman, Chem. Soc. Rev., 2005, 34, 355.
28. I. P. Singh, S. B. Bharate and K. K. Bhutani, Curr. Sci., 2005, 89, 269.
29. N. Dias, H. Vezin, A. Lansiaux and C. Bailly, Top. Curr. Chem., 2005, 253, 89.
30. L. Zhang, R. An, J. Wang, N. Sun, S. Zhang, J. Hu and J. Kuai, Curr. Opin. Microbiol., 2005, 8, 276.
31. A. T. Bull, J. E. M. Stach, A. C. Ward and M. Goodfellow, Antonie van Leeuwenhoek, 2005, 87, 65.
32. C. Imada, Antonie van Leeuwenhoek, 2005, 87, 59.
33. B. S. Moore, J. A. Kalaitzis and L. Xiang, Antonie van Leeuwenhoek, 2005, 87, 49.
34. P. R. Jensen, T. J. Mincer, P. G. Williams and W. Fenical, Antonie van Leeuwenhoek, 2005, 87, 43.
35. H. P. Fiedler, C. Bruntner, A. T. Bull, A. C. Ward, M. Goodfellow, O. Potterat, C. Puder and G. Mihm, Antonie van Leeuwenhoek, 2005, 87, 37.
36. J. Clayden, B. Read and K. R. Hebditch, Tetrahedron, 2005, 61, 5713.
37. T. Yasumoto, Proc. Jpn. Acad., Ser. B, 2005, 81, 43.
38. K. Yasumoto, Kagaku to Seibutsu, 2005, 43, 153.
39. C. Wiegand and S. Pflugmacher, Toxicol. Appl. Pharmacol., 2005, 203, 201.
40. M. A. Friedman and B. E. Levin, J. Int. Neuropsychol. Soc., 2005, 11, 331.
41. L. E. Fleming, L. C. Backer and D. G. Baden, Environ. Health Perspect., 2005, 113, 618.
42. G. P. Rossini, Toxicology, 2005, 207, 451.
43. M. C. C. Batoréu, E. Dias, P. Pereira and S. Franca, Environ. Toxicol. Pharmacol., 2005, 19, 401.
44. G. A. Codd, L. F. Morrison and J. S. Metcalf, Toxicol. Appl. Pharmacol., 2005, 203, 264.
45. Y. Harayama and Y. Kita, Curr. Org. Chem., 2005, 9, 1567.
46. E. M. Antunes, B. R. Copp, M. T. Davies-Coleman and T. Samaai, Nat. Prod. Rep., 2005, 22, 62.
47. L. N. Rogosa, N. F. Salakhutdinov and G. A. Tolstikov, Russ. J. Bioorg. Chem., 2005, 31, 507.
48. J. P. Bergé and G. Barnathan, Adv. Biochem. Eng. Biotechnol., 2005, 96, 49.
49. W. Gul and M. T. Hamann, Life Sci., 2005, 78, 442.
50. M. Somei and F. Yamada, Nat. Prod. Rep., 2005, 22, 73.
51. R. G. S. Berlinck and M. H. Kossuga, Nat. Prod. Rep., 2005, 22, 516.
52. J.-F. Liu, S.-P. Guo and B. Jiang, Chin. J. Org. Chem., 2005, 25, 788.
53. T. Ogamino and S. Nishiyama, J. Synth. Org. Chem., Jpn., 2005, 63, 583.
54. J. D. Connolly and R. A. Hill, Nat. Prod. Rep., 2005, 22, 230.
55. Z. Jin, Nat. Prod. Rep., 2005, 22, 196.
56. V. M. Dembitsky, T. A. Gloriozova and V. V. Poroikov, Mini–Rev. Med. Chem., 2005, 5, 319.
57. M. Kita and D. Uemura, Chem. Lett., 2005, 34, 454.
58. M. Ohba, Recent Res. Dev. Org. Chem., 2005, 9, 71.
59. N. S. Sarma, M. S. R. Krishna and S. R. Rao, Mar. Drugs, 2005, 3, 84.
60. P.-J. Sung, P.-C. Chang, L.-S. Fang, J.-H. Sheu, W.-C. Chen, Y.-P. Chen and M.-R. Lin, Heterocycles, 2005, 65, 195.
61. B. S. Moore, Nat. Prod. Rep., 2005, 22, 580.
62. A. Fontana, A. Cutignano and G. d'Ippolito, in Biocatalysis: Chemistry and Biology, ed. A. Trincone, Research Signpost, Trivandrum, India, 2005, p. 167.
63. J. L. Fortman and D. H. Sherman, ChemBioChem, 2005, 6, 960.
64. J. Piel, D. Butzke, N. Fusetani, D. Hui, M. Platzer, G. Wen and S. Matsunaga, J. Nat. Prod., 2005, 68, 472.
65. J. Piel, Naturwiss. Rundsch., 2005, 58, 5.
66. G. M. Nicholas and A. J. Phillips, Nat. Prod. Rep., 2005, 22, 144.
67. W. E. Houssen and M. Jaspars, Methods Biotechnol., 2005, 20, 353.
68. MarinLit database, Department of Chemistry, University of Canterbury: http://www.chem.canterbury.ac.nz/marinlit/marinlit.shtml.
69. R. H. Feling, G. O. Buchanan, T. J. Mincer, C. A. Kauffman, P. R. Jensen and W. Fenical, Angew. Chem., Int. Ed., 2003, 42, 355.
70. P. G. Williams, G. O. Buchanan, R. H. Feling, C. A. Kauffman, P. R. Jensen and W. Fenical, J. Org. Chem., 2005, 70, 6196.
71. G. O. Buchanan, P. G. Williams, R. H. Feling, C. A. Kauffman, P. R. Jensen and W. Fenical, Org. Lett., 2005, 7, 2731.
72. D. S. Fukuda, J. S. Mynderse, P. J. Baker, D. M. Berry, L. D. Boeck, R. C. Yao, F. P. Mertz, W. M. Nakatsukasa, J. Mabe and J. Ott, J. Antibiot., 1990, 43, 623.
73. D. S. Fukuda, J. S. Mynderse and R. C. Yao, U.S. Patent 4904590, 1990.
74. I. E. Soria-Mercado, P. R. Jensen, W. Fenical, S. Kassel and J. Golen, Acta Crystallogr., Sect. E, 2004, 60, 1627.
75. I. E. Soria-Mercado, A. Prieto-Davo, P. R. Jensen and W. Fenical, J. Nat. Prod., 2005, 68, 904.
76. Y. Matsuo, M. Suzuki, H. Kasai, Y. Shizuri and S. Harayama, Environ. Microbiol., 2003, 5, 25.
77. Y. Matsuo, H. Imagawa, M. Nishizawa and Y. Shizuri, Science, 2005, 307, 1598.
78. K. Kanoh, Y. Matsuo, K. Adachi, H. Imagawa, M. Nishizawa and Y. Shizuri, J. Antibiot., 2005, 58, 289.
79. P. Romero, L. Malet, L. M. Canedo, C. Cuevas and J. Fernando Reyes, PCT Int. Appl., WO 2005000880 A2 20050106, 2005.
80. A. J. Blackman and C. Li, Aust. J. Chem., 1994, 47, 1625.
81. N. Lindquist and W. Fenical, Experientia, 1991, 47, 504.
82. B. Carte and D. J. Faulkner, J. Org. Chem., 1983, 48, 2314.
83. C. Holmstrom, S. James, B. A. Neilan, D. C. White and S. Kjelleberg, Int. J. Syst. Bacteriol., 1998, 48, 1205.
84. A. Franks, P. Haywood, C. Holmström, S. Egan, S. Kjelleberg and N. Kumar, Molecules, 2005, 10, 1286.
85. J. Vicar, M. Budesinsky and K. Blaha, Collect. Czech. Chem. Commun., 1973, 38, 1940.
86. J. Vicar, J. Smolikova and K. Blaha, Collect. Czech. Chem. Commun., 1973, 38, 1957.
87. M. Mitova, M. L. Tutino, G. Infusini, G. Marino and S. De Rosa, Mar. Biotechnol., 2005, 7, 523.
88. R. R. Manam, S. Teisan, D. J. White, B. Nicholson, J. Grodberg, S. T. C. Neuteboom, K. S. Lam, D. A. Mosca, G. K. Lloyd and B. C. M. Potts, J. Nat. Prod., 2005, 68, 240.
89. F. Li, R. P. Maskey, S. Qin, I. Sattler, H. H. Fiebig, A. Maier, A. Zeeck and H. Laatsch, J. Nat. Prod., 2005, 68, 349.
90. H.-S. Lee, H. J. Shin, K. H. Jang, T. S. Kim, K.-B. Oh and J. Shin, J. Nat. Prod., 2005, 68, 623.
91. V. R. Macherla, J. Liu, C. Bellows, S. Teisan, B. Nicholson, K. S. Lam and B. C. M. Potts, J. Nat. Prod., 2005, 68, 780.
92. I. Kock, R. P. Maskey, M. A. F. Biabani, E. Helmke and H. Laatsch, J. Antibiot., 2005, 58, 530.
93. A. Gorajana, B. V. V. S. N. Kurada, S. Peela, P. Jangam, S. Vinjamuri, E. Poluri and A. Zeeck, J. Antibiot., 2005, 58, 526.
94. Y.-Q. Tang, I. Sattler, R. Thiericke, S. Grabley and X.-Z. Feng, J. Antibiot., 2000, 53, 934.
95. M. P. Sobolevskaya, S. Fotso, U. Havash, V. A. Denisenko, E. Helmke, N. G. Prokofeva, T. A. Kuznetsova, H. Laatsch and G. B. Elyakov, Chem. Nat. Compd., 2004, 40, 282.
96. W. H. Kim, J. H. Jung and E. Lee, J. Org. Chem., 2005, 70, 8190.
97. H. Mertens, O. Schmidt and K. Adam, Patents DE 1083011, 1960, and GB 875720.
98. J. F. McGhie, W. A. Ross, D. Evans and J. E. Tomlin, J. Chem. Soc., 1962, 350.
99. J. S. Dickschat, T. Martens, T. Brinkhoff, M. Simon and S. Schulz, Chem. Biodiversity, 2005, 2, 837.
100. R. K. Phipps, J. W. Blunt, A. L. J. Cole and M. H. G. Munro, ARKIVOC, 2004, 94.
101. X.-X. Han, C.-B. Cui, Q.-Q. Gu, W.-M. Zhu, H.-B. Liu, J.-Y. Gu and H. Osada, Tetrahedron Lett., 2005, 46, 6137.
102. T. Mülhaupt, H. Kaspar, S. Otto, M. Reichert, G. Bringmann and T. Lindel, Eur. J. Org. Chem., 2005, 2, 334.
103. M. Winter, F. Gautschi, I. Flament, M. Stoll and I. M. Goldman, U.S. Patent, 3924015, 1975.
104. J. S. Dickschat, H. Reichenbach, I. Wagner-Döbler and S. Schulz, Eur. J. Org. Chem., 2005, 4141.
105. S. Tsukamoto, H. Hirota, M. Imachi, M. Fujimuro, H. Onuki, T. Ohta and H. Yokosawa, Bioorg. Med. Chem. Lett., 2005, 15, 191.
106. S. A. Waksman, E. S. Horning and E. L. Spencer, Science, 1942, 96, 202.
107. K. Tatsuta, T. Tsuchiya, N. Mikami, S. Umezawa, H. Umezawa and H. Naganawa, J. Antibiot., 1974, 27, 579.
108. O. F. Smetanina, A. I. Kalinovskii, Y. V. Khudyakov, O. P. Moiseenko, M. V. Pivkin, N. I. Menzorova, Y. T. Sibirtsev and T. A. Kuznetsova, Chem. Nat. Compd., 2005, 41, 243.
109. M.-A. Ouyang, R. Liu and Y.-H. Kuo, J. Asian Nat. Prod. Res., 2005, 7, 761.
110. M. Tsuda, M. Sasaki, T. Mugishima, K. Komatsu, T. Sone, M. Tanaka, Y. Mikami and J. Kobayashi, J. Nat. Prod., 2005, 68, 273.
111. M. Sasaki, M. Tsuda, M. Sekiguchi, Y. Mikami and J. Kobayashi, Org. Lett., 2005, 7, 4261.
112. M. Tsuda, Y. Kasai, K. Komatsu, T. Sone, M. Tanaka, Y. Mikami and J. Kobayashi, Org. Lett., 2004, 6, 3087.
113. T. Mugishima, M. Tsuda, Y. Kasai, H. Ishiyama, E. Fukushi, J. Kawabata, M. Watanabe, K. Akao and J. Kobayashi, J. Org. Chem., 2005, 70, 9430.
114. G. Bringmann, G. Lang, T. A. M. Gulder, H. Tsuruta, J. Mühlbacher, K. Maksimenka, S. Steffens, K. Schaumann, R. Stöhr, J. Wiese, J. F. Imhoff, S. Perovic-Ottstadt, O. Boreiko and W. E. G. Müller, Tetrahedron, 2005, 61, 7252.
115. W. Liu, Q. Gu, W. Zhu, C. Cui, G. Fan, T. Zhu, H. Liu and Y. Fang, Tetrahedron Lett., 2005, 46, 4993.
116. W. Liu, Q. Gu, W. Zhu, C. Cui and G. Fan, J. Antibiot., 2005, 58, 441.
117. W. Liu, Q. Gu, W. Zhu, C. Cui and G. Fan, J. Antibiot., 2005, 58, 621.
118. R. Andrarde, W. A. Ayer and P. P. Mebe, Can. J. Chem., 1992, 70, 2526.
119. N. Abe, T. Murata and A. Hirota, Biosci., Biotechnol., Biochem., 1998, 62, 661.
120. G. A. Warr, J. A. Veitch, A. W. Walsh, G. A. Hesler, D. M. Pirnit, J. E. Leet, P.-F. M. Lin, I. A. Medina, K. D. McBrien, S. Forenza, J. M. Clark and K. S. Lam, J. Antibiot., 1996, 49, 234.
121. J. He, U. Lion, I. Sattler, F. A. Gollmick, S. Grabley, J. Cai, M. Meiners, H. Schünke, K. Schaumann, U. Dechert and M. Krohn, J. Nat. Prod., 2005, 68, 1397.
122. Z. H. Xin, W. M. Zhu, Q. Q. Gu, Y. C. Fang, L. Duan and C. B. Cui, Chin. Chem. Lett., 2005, 16, 1227.
123. A. Takatsuki, S. Suzuki, K. Ando, G. Tamura and K. Arima, J. Antibiot., 1968, 21, 671.
124. R. Sakai, T. Nakamura, T. Nishino, M. Yamamoto, A. Miyamura, H. Miyamoto, N. Ishiwata, N. Komatsu, H. Kamiya and N. Tsuruzoe, Bioorg. Med. Chem., 2005, 13, 6388.
125. K. Adachi, K. Kanoh, P. Wisespongp, M. Nishijima and Y. Shizuri, J. Antibiot., 2005, 58, 145.
126. K. Krohn, J. Dai, U. Flörke, H.-J. Aust, S. Dräger and B. Schulz, J. Nat. Prod., 2005, 68, 400.
127. X. Li, M. K. Kim, U. Lee, S.-K. Kim, J. S. Kang, H. D. Choi and B. W. Son, Chem. Pharm. Bull., 2005, 53, 453.
128. Y. Kasai, K. Komatsu, H. Shigemori, M. Tsuda, Y. Mikami and J. Kobayashi, J. Nat. Prod., 2005, 68, 777.
129. H. Wei, T. Itoh, M. Kinoshita, N. Kotoku, S. Aoki and M. Kobayashi, Tetrahedron, 2005, 61, 8054.
130. T. Yamada, M. Iritani, K. Minoura, K. Kawai and A. Numata, Org. Biomol. Chem., 2004, 2, 2131.
131. T. Yamada, M. Doi, A. Miura, W. Harada, M. Hiramura, K. Minoura, R. Tanaka and A. Numata, J. Antibiot., 2005, 58, 185.
132. M. Cueto, P. R. Jensen, C. Kauffman, W. Fenical, E. Lobkovsky and J. Clardy, J. Nat. Prod., 2001, 64, 1444.
133. D.-C. Oh, P. R. Jensen, C. A. Kauffman and W. Fenical, Bioorg. Med. Chem., 2005, 13, 5267.
134. C. J. Smith, D. Abbanat, V. S. Bernan, W. M. Maiese, M. Greenstein, J. Jompa, A. Tahir and C. M. Ireland, J. Nat. Prod., 2000, 63, 142.
135. R. Garcia, J. M. Seco, S. A. Vazquez, E. Quinoa and R. Riguera, J. Org. Chem., 2002, 67, 4579.
136. X. Franck, M. E. Vaz Araujo, J.-C. Jullian, R. Hocquemiller and B. Figadere, Tetrahedron Lett., 2001, 42, 2801.
137. S. Gesner, N. Cohen, M. Ilan, O. Yarden and S. Carmeli, J. Nat. Prod., 2005, 68, 1350.
138. A. M. J. Senderowicz, G. Kaur, E. Sainz, C. Laing, W. D. Inman, J. Rodriguez, P. Crews, L. Malspeis, M. R. Grever, E. A. Sausville and K. L. K. Duncan, J. Natl. Cancer Inst., 1995, 87, 46.
139. P. Crews, L. V. Manes and M. Boehler, Tetrahedron Lett., 1986, 27, 2797.
140. T. M. Zabriskie, J. A. Klocke, C. M. Ireland, A. H. Marcus, T. F. Molinski, D. J. Faulkner, C. Xu and J. Clardy, J. Am. Chem. Soc., 1986, 108, 3123.
141. O. E. Christian, J. Compton, K. R. Christian, S. L. Mooberry, F. A. Valeriote and P. Crews, J. Nat. Prod., 2005, 68, 1592.
142. X. Wu, X. Liu, G. Jiang, Y. Lin, W. Chan and L. L. P. Vrijmoed, Chem. Nat. Compd., 2005, 41, 27.
143. Y. Lin, X. Wu, S. Feng, G. Jiang, J. Luo, S. Zhou, L. L. Vrijmoed, E. B. Jones, K. Krohn, K. Steingrover and F. Zsila, J. Org. Chem., 2001, 66, 6252.
144. X. Y. Wu, X. H. Liu, Y. C. Lin, J. H. Luo, Z. G. She, L. Houjin, W. L. Chan, S. Antus, T. Kurtan, B. Elsässer and K. Krohn, Eur. J. Org. Chem., 2005, 4061.
145. H. Raistrick and D. J. Ross, Biochem. J., 1952, 50, 635.
146. P. Cai, A. T. McPhail, E. Krainer, B. Katz, C. Pearce, C. Boros, B. Caceres, D. Smith and D. R. Houck, Tetrahedron Lett., 1999, 40, 1479.
147. X. Lin, Y. Huang, M. Fang, J. Wang, Z. Zheng and W. Su, FEMS Microbiol. Lett., 2005, 251, 53.
148. B. Han, K. L. McPhail, H. Gross, D. E. Goeger, S. L. Mooberry and W. H. Gerwick, Tetrahedron, 2005, 61, 11723.
149. B. Han, D. Goeger, C. S. Maier and W. H. Gerwick, J. Org. Chem., 2005, 70, 3133.
150. S. Carmely and Y. Kashman, Tetrahedron Lett., 1985, 26, 511.
151. E. H. Andrianasolo, H. Gross, D. Goeger, M. Musafija-Girt, K. McPhail, R. M. Leal, S. L. Mooberry and W. H. Gerwick, Org. Lett., 2005, 7, 1375.
152. T. Teruya, K. Kobayashi, K. Suenaga and H. Kigoshi, Tetrahedron Lett., 2005, 46, 4001.
153. J. B. MacMillan and T. F. Molinski, J. Nat. Prod., 2005, 68, 604.
154. Y. Ito and A. Butler, Limnol. Oceanogr., 2005, 50, 1918.
155. N. Morsy, S. Matsuoka, T. Houdai, N. Matsumori, S. Adachi, M. Murata, T. Iwashita and T. Fujita, Tetrahedron, 2005, 61, 8606.
156. R. Echigoya, L. Rhodes, Y. Oshima and M. Satake, Harmful Algae, 2005, 4, 383.
157. T. Kubota, A. Takahashi, M. Tsuda and J. Kobayashi, Mar. Drugs, 2005, 3, 113.
158. M. Tsuda, Y. Kariya, R. Iwamoto, E. Fukushi, J. Kawabata and J. Kobayashi, Mar. Drugs, 2005, 3, 1.
159. J. Wu, L. J. Long, Y. Song, S. Zhang, Q. X. Li, H. S. Huang and Z. H. Xiao, Chem. Pharm. Bull., 2005, 53, 330.
160. M. L. Souto, J. J. Fernández, J. M. Franco, B. Paz, L. V. Gil and M. Norte, J. Nat. Prod., 2005, 68, 420.
161. C. O. Miles, A. L. Wilkins, A. D. Hawkes, A. Selwood, D. J. Jensen, J. Aasen, R. Munday, I. A. Samdal, L. R. Briggs, V. Beuzenberg and A. L. MacKenzie, Toxicon, 2004, 44, 325.
162. C. O. Miles, A. L. Wilkins, A. D. Hawkes, A. I. Selwood, D. J. Jensen, R. Munday, J. M. Cooney and V. Beuzenberg, Toxicon, 2005, 45, 61.
163. J. Aasen, S. L. MacKinnon, P. LeBlanc, J. A. Walter, P. Hovgaard, T. Aune and M. A. Quilliam, Chem. Res. Toxicol., 2005, 18, 509.
164. M. Satake, Y. Tanaka, Y. Ishikura, Y. Oshima, H. Naoki and T. Yasumoto, Tetrahedron Lett., 2005, 46, 3537.
165. K. Tanaka, Y. Itagaki, M. Satake, H. Naoki, T. Yasumoto, K. Nakanishi and N. Berova, J. Am. Chem. Soc., 2005, 127, 9561.
166. A. J. Bourdelais, H. M. Jacocks, J. L. C. Wright, P. M. Bigwarfe, Jr. and D. G. Baden, J. Nat. Prod., 2005, 68, 2.
167. B. Suárez-Gómez, M. L. Souto, P. G. Cruz, J. J. Fernández and M. Norte, J. Nat. Prod., 2005, 68, 596.
168. C.-K. Lu, H.-N. Chou, C.-K. Lee and T.-H. Lee, Org. Lett., 2005, 7, 3893.
169. M. Kita, M. Kondo, T. Koyama, K. Yamada, T. Matsumoto, K.-H. Lee, J.-T. Woo and D. Uemura, J. Am. Chem. Soc., 2004, 126, 4794.
170. M. Kita, N. Ohishi, K. Washida, M. Kondo, T. Koyama, K. Yamada and D. Uemura, Bioorg. Med. Chem., 2005, 13, 5253.
171. A. A. Carlos, B. K. Baillie, M. Kawachi and T. Maruyama, J. Phycol., 1999, 35, 1054.
172. K. Onodera, H. Nakamura, Y. Oba and M. Ojika, Tetrahedron, 2003, 59, 1067.
173. K. Onodera, H. Nakamura, Y. Oba, Y. Ohizumi and M. Ojika, J. Am. Chem. Soc., 2005, 127, 10406.
174. G. d'Ippolito, A. Cutignano, R. Briante, F. Febbraio, G. Cimino and A. Fontana, Org. Biomol. Chem., 2005, 3, 4065.
175. A. P. Rauter, M. M. Filipe, C. Prata, J. P. Noronha, M. A. M. Sampayo, J. Justino and J. Bermejo, Fitoterapia, 2005, 76, 433.
176. J. Hiort, K. Maksimenka, M. Reichert, S. Perovic-Ottstadt, W. H. Lin, V. Wray, K. Steube, K. Schaumann, H. Weber, P. Proksch, R. Ebel, W. E. G. Mueller and G. Bringmann, J. Nat. Prod., 2004, 67, 1532.
177. J. Hiort, K. Maksimenka, M. Reichert, S. Perovic-Ottstadt, W. H. Lin, V. Wray, K. Steube, K. Schaumann, A. Weber, P. Proksch, R. Ebel, W. E. G. Müller and G. Bringmann, J. Nat. Prod., 2005, 68, 1821.
178. Y. H. Ye, H. L. Zhu, Y. C. Song, J. Y. Liu and R. X. Tan, J. Nat. Prod., 2005, 68, 1106.
179. J. I. Jimenez and P. J. Scheuer, J. Nat. Prod., 2001, 64, 200.
180. H. Chen, Y. Feng, Z. Xu and T. Ye, Tetrahedron, 2005, 61, 11132.
181. D. B. Stierle and A. A. Stierle, Experientia, 1992, 48, 1165.
182. X. Gao and D. G. Hall, J. Am. Chem. Soc., 2005, 127, 1628.
183. T. S. Bugni, D. Abbanat, V. S. Bernan, W. M. Maiese, M. Greenstein, R. M. Van Wagoner and C. M. Ireland, J. Org. Chem., 2000, 65, 7195.
184. G. Mehta and S. C. Pan, Tetrahedron Lett., 2005, 46, 5219.
185. B. Bister, D. Bischoff, M. Ströbele, J. Riedlinger, A. Reicke, F. Wolter, A. T. Bull, H. Zähner, H.-P. Fiedler and R. D. Süssmuth, Angew. Chem., Int. Ed., 2004, 43, 2574.
186. C. W. Zapf, B. A. Harrison, C. Drahl and E. J. Sorensen, Angew. Chem., Int. Ed., 2005, 44, 6533.
187. M. K. Renner, Y. C. Shen, X. C. Cheng, P. R. Jensen, W. Frankmolle, C. A. Kauffman, W. Fenical, E. Lobkovsky and J. Clardy, J. Am. Chem. Soc., 1999, 121, 11273.
188. S. J. Wen, T. S. Hu and Z. J. Yao, Tetrahedron, 2005, 61, 4931.
189. B. Han, K. L. McPhail, A. Ligresti, V. Di Marzo and W. H. Gerwick, J. Nat. Prod., 2003, 66, 1364.
190. I. R. Davies, M. Cheeseman, D. Gangani Niyadurupola and S. D. Bull, Tetrahedron Lett., 2005, 46, 5547.
191. H. Luesch, R. Pangilinan, W. Y. Yoshida, R. E. Moore and V. J. Paul, J. Nat. Prod., 2001, 64, 304.
192. Y. Peng, H. Pang, Z. Xu and T. Ye, Lett. Org. Chem., 2005, 2, 703.
193. M. Yamazaki, H. Fujimoto and E. Okuyama, Chem. Pharm. Bull., 1978, 26, 111.
194. S. S. Afiyatullov, A. I. Kalinovskii, M. V. Pivkin, P. S. Dmitrenok and T. A. Kuznetsova, Chem. Nat. Compd., 2005, 41, 236.
195. H. H. Wasserman, G. C. Rodgers and D. D. Keith, J. Am. Chem. Soc., 1969, 91, 1263.
196. R. Liu, C.-B. Cui, L. Duan, Q.-Q. Gu and W.-M. Zhu, Arch. Pharm. Res., 2005, 28, 1341.
197. F. Peypoux, F. Besson, G. Michel, C. Lenzen, L. Dierickx and L. Delcambe, J. Antibiot., 1980, 33, 1146.
198. G. K. Oleinikova, A. S. Dmitrenok, V. G. Voinov, E. L. Chaikina, L. S. Shevchenko and T. A. Kuznetsova, Chem. Nat. Compd., 2005, 41, 461.
199. G. K. Oleinikova, A. S. Dmitrenok, V. G. Voinov, E. L. Chaikina, L. S. Shevchenko and T. A. Kuznetsova, Chem. Nat. Compd., 2005, 41, 240.
200. A. Closse, R. Mauli, H. P. Sigg and A. G. Sandoz, Helv. Chim. Acta, 1965, 49, 204.
201. G. Assante, L. Camarda, G. Nasini and L. Merlini, Phytopathol. Mediterr., 1980, 19, 163.
202. M. Sequin-Frey and C. Tamm, Helv. Chim. Acta, 1971, 54, 851.
203. A. R. Burnett and R. H. Thomson, J. Chem. Soc. C, 1968, 857.
204. Y. Li, X. Li and B. W. Son, Nat. Prod. Sci., 2005, 11, 136.
205. T. Seki, M. Satake, L. Mackenzie, H. F. Kaspar and T. Yasumoto, Tetrahedron Lett., 1995, 36, 7093.
206. M. Dragunow, M. Trzoss, M. A. Brimble, R. Cameron, V. Beuzenberg, P. Holland and D. Mountfort, Environ. Toxicol. Pharmacol., 2005, 20, 305.
207. F. M. Lovel, J. Am. Chem. Soc., 1966, 88, 4510.
208. P. R. Burkholder, R. M. Pfister and F. H. Leitz, Appl. Microbiol., 1966, 14, 649.
209. J. D. Peschke, U. Hanefeld and H. Laatsch, Biosci., Biotechnol., Biochem., 2005, 69, 628.
210. A. D. Rodriguez, J.-G. Shi and S. D. Huang, J. Nat. Prod., 1999, 62, 1228.
211. J. M. Boehnlein, L. Z. Santiago-Vázquez and R. G. Kerr, Mar. Ecol.: Prog. Ser., 2005, 303, 105.
212. J. S. Sandler, W. Fenical, B. M. Gulledge, A. R. Chamberlin and J. J. La Clair, J. Am. Chem. Soc., 2005, 127, 9320.
213. J. W. Blunt, B. R. Copp, M. H. G. Munro, P. T. Northcote and M. R. Prinsep, Nat. Prod. Rep., 2006, 23, 26.
214. H. Kogen, K. Tago, S. Kaneko, K. Hamano, K. Onodera, H. Haruyama, K. Minagawa, T. Kinoshita, T. Ishikawa, T. Tanimoto and Y. Tsujita, J. Antibiot., 1996, 49, 624.
215. J. T. Handley and A. J. Blackman, Aust. J. Chem., 2005, 58, 39.
216. R. J. Andersen and O. Taglialatela-Scafati, J. Nat. Prod., 2005, 68, 1428.
217. D. Y. Shi, L. J. Han, J. Sun, S. Li, S. J. Wang, Y. C. Yang, X. Fan and J. G. Shi, Chin. Chem. Lett., 2005, 16, 777.
218. S.-W. Yin, C.-Y. Wang, X.-M. Li and B.-G. Wang, Biochem. Syst. Ecol., 2005, 33, 1288.
219. M. T. Hamann, C. S. Otto, P. J. Scheuer and D. C. Dunbar, J. Org. Chem., 1996, 61, 6594.
220. M. T. Hamann, C. S. Otto, P. J. Scheuer and D. C. Dunbar, J. Org. Chem., 1998, 63, 4856.
221. L. Bourel-Bonnet, K. V. Rao, M. T. Hamann and A. Ganesan, J. Med. Chem., 2005, 48, 1330.
222. T. Kajiwara, A. Hatanaka, T. Kawai, M. Ishihara and T. Tuneya, Nippon Suisan Gakkaishi, 1987, 53, 1901.
223. Y. Akakabe, K. Washizu, K. Matsui and T. Kajiwara, Biosci., Biotechnol., Biochem., 2005, 69, 1348.
224. K. H. Jang, B. H. Lee, B. W. Choi, H.-S. Lee and J. Shin, J. Nat. Prod., 2005, 68, 716.
225. K. Inaoka, Y. Nishizawa, H. Tone and T. Kamiya, Jpn. Kokai Tokkyo Koho, JP H04-49259, 1992.
226. M. Iwashima, J. Mori, X. Ting, T. Matsunaga, K. Hayashi, D. Shinoda, H. Saito, U. Sankawa and T. Hayashi, Biol. Pharm. Bull., 2005, 28, 374.
227. J. Mori, M. Iwashima, H. Wakasugi, H. Saito, T. Matsunaga, M. Ogasawara, S. Takahashi, H. Suzuki and T. Hayashi, Chem. Pharm. Bull., 2005, 53, 1159.
228. D. Abatis, C. Vagias, D. Galanakis, J. N. Norris, D. Moreau, C. Roussakis and V. Roussis, Tetrahedron Lett., 2005, 46, 8525.
229. M. Ishitsuka, T. Kusumi, Y. Nomura, T. Konno and H. Kakisawa, Chem. Lett., 1979, 1269.
230. L.-A. Tziveleka, D. Abatis, K. Paulus, R. Bauer, C. Vagias and V. Roussis, Chem. Biodiversity, 2005, 2, 901.
231. W. H. Gerwick, W. Fenical, N. Fritsch and J. Clardy, Tetrahedron Lett., 1979, 145.
232. O. M. M. Sabry, S. Andrews, K. L. McPhail, D. E. Goeger, A. Yokochi, K. T. LePage, T. F. Murray and W. H. Gerwick, J. Nat. Prod., 2005, 68, 1022.
233. F. Song, X. Xu, S. Li, S. Wang, J. Zhao, P. Cao, Y. Yang, X. Fan, J. Shi, L. He and Y. Lü, J. Nat. Prod., 2005, 68, 1309.
234. A. Ortalo-Magné, G. Culioli, R. Valls, B. Pucci and L. Piovetti, Phytochemistry, 2005, 66, 2316.
235. J. F. Biard, J. F. Verbist, R. Floch and Y. Letourneux, Tetrahedron Lett., 1980, 21, 1849.
236. T. Kusumi, Y. Shibata, M. Ishizuka, T. Kinoshita and H. Kakizawa, Chem. Lett., 1979, 277.
237. C. K. Tsang, A. Ina, T. Goto and Y. Kamei, Neuroscience, 2005, 132, 633.
238. C. F. Cross, E. J. Bevan and J. F. Briggs, Chem.–Ztg., 1907, 31, 725.
239. H. S. Kang, H. Y. Chung, J. H. Jung, B. W. Son and J. S. Choi, Chem. Pharm. Bull., 2003, 51, 1012.
240. Y. Fukuyama, M. Kodama, I. Miura, Z. Kinzyo, M. Kido, H. Mori, Y. Nakayama and M. Takahashi, Chem. Pharm. Bull., 1989, 37, 349.
241. Y. Fukuyama, M. Kodama, I. Miura, Z. Kinzyo, H. Mori, Y. Nakayama and M. Takahashi, Chem. Pharm. Bull., 1990, 38, 133.
242. Y. Fukuyama, I. Miura, Z. Kinzyo, Y. Nakayama, M. Takahashi and M. Kido, Tennen Yuki Kagobutsu Toronkai Koen Yoshishu, 1983, 26, 126.
243. Y. C. Kim, R. B. An, N. Y. Yoon, T. J. Nam and J. S. Choi, Arch. Pharm. Res., 2005, 28, 1376.
244. M. Ochi, H. Kotsuki, K. Muraoka and T. Tokoroyama, Bull. Chem. Soc. Jpn., 1979, 52, 629.
245. K. Kurata, K. Taniguchi and M. Suzuki, Phytochemistry, 1996, 41, 749.
246. W. Fenical, J. J. Sims, D. Squatrito, R. M. Wing and P. Radlick, J. Org. Chem., 1973, 38, 2383.
247. T. Laube, W. Beil and K. Seifert, Tetrahedron, 2005, 61, 1141.
248. A. A. El-Gamal, W.-L. Wang and C.-Y. Duh, J. Nat. Prod., 2005, 68, 815.
249. N. K. Kubota, H. Iwamoto, Y. Fukazawa and Y. Uchio, Heterocycles, 2005, 65, 2675.
250. J. Sun, D. Shi, M. Ma, S. Li, S. Wang, L. Han, Y. Yang, X. Fan, J. Shi and L. He, J. Nat. Prod., 2005, 68, 915.
251. K. Yamada, H. Yazawa, D. Uemura, M. Toda and Y. Hirata, Tetrahedron, 1969, 25, 3509.
252. H. Nemoto, M. Nagamochi, H. Ishibashi and K. Fukumoto, J. Org. Chem., 1994, 59, 74.
253. J. Sun, L. J. Han, D. Y. Shi, X. Fan, S. J. Wang, S. Li, Y. C. Yang and J. G. Shi, Chin. Chem. Lett., 2005, 16, 1611.
254. D. J. Goldsmith, T. K. John, C. D. Kwong and G. R. Painter, III, J. Org. Chem., 1980, 45, 3989.
255. Y. Shizuri and K. Yamada, Phytochemistry, 1985, 24, 1385.
256. M. Kladi, C. Vagias, G. Furnari, D. Moreau, C. Roussakis and V. Roussis, Tetrahedron Lett., 2005, 46, 5723.
257. S. Mao and Y. Guo, Helv. Chim. Acta, 2005, 88, 1034.
258. J. J. Fernández, M. L. Souto, L. V. Gil and M. Norte, Tetrahedron, 2005, 61, 8910.
259. M. Kuniyoshi, P. G. Wahome, T. Miono, T. Hashimoto, M. Yokoyama, K. L. Shrestha and T. Higa, J. Nat. Prod., 2005, 68, 1314.
260. M. Suzuki, T. Kawamoto, C. S. Vairappan, T. Ishii, T. Abe and M. Masuda, Phytochemistry, 2005, 66, 2787.
261. O. J. McConnell and W. Fenical, J. Org. Chem., 1978, 43, 4238.
262. V. J. Paul, O. J. McConnell and W. Fenical, J. Org. Chem., 1980, 45, 3401.
263. J. Kimura, Y. Tobita, T. Motoyama, Y. Ataka and Y. Takada, J. Nat. Prod., 2005, 68, 585.
264. S. Mataka, H. Eguchi, K. Takahashi, T. Hatta and M. Tashiro, Bull. Chem. Soc. Jpn., 1989, 62, 3127.
265. K. Nishizawa and J. Y. Satoh, Chem. Soc. Jpn., 1975, 48, 1875.
266. J. E. Lightowler and H. J. Rylance, Br. J. Pharmacol., 1964, 22, 221.
267. V. L. Afanas'eva, A. V. Lyubeshkin, S. S. Kovaleva, M. R. Bagreeva, O. S. Anisimova and R. G. Glushkov, Khim.-Farm. Zh., 1987, 21, 1367.
268. W. Wang, Y. Okada, H. Shi, Y. Wang and T. Okuyama, J. Nat. Prod., 2005, 68, 620.
269. J. Zhao, M. Ma, S. Wang, S. Li, P. Cao, Y. Yang, Y. Lü, J. Shi, N. Xu, X. Fan and L. He, J. Nat. Prod., 2005, 68, 691.
270. D. B. Stierle, R. M. Wing and J. J. Sims, Tetrahedron, 1979, 35, 2855.
271. M. D. Higgs, D. J. Vanderah and D. J. Faulkner, Tetrahedron, 1977, 33, 2775.
272. C. Ireland, M. O. Stallard, D. J. Faulkner, J. Finer and J. Clardy, J. Org. Chem., 1976, 41, 2461.
273. M. G. Knott, H. Mkwananzi, C. E. Arendse, D. T. Hendricks, J. J. Bolton and D. R. Beukes, Phytochemistry, 2005, 66, 1108.
274. W.-H. Zhang, H.-M. Zhong and C.-T. Che, J. Asian Nat. Prod. Res., 2005, 7, 59.
275. M. Lorenzo, M. Cueto, A. San-Martín, V. Fajardo and J. Darias, Tetrahedron, 2005, 61, 9550.
276. M. Kitamura, T. Koyama, Y. Nakano and D. Uemura, Chem. Lett., 2005, 34, 1272.
277. J. Kubanek, A. C. Prusak, T. W. Snell, R. A. Giese, K. I. Hardcastle, C. R. Fairchild, W. Aalbersberg, C. Raventos-Suarez and M. E. Hay, Org. Lett., 2005, 7, 5261.
278. M. A. Graber, W. H. Gerwick and D. P. Cheney, Tetrahedron Lett., 1996, 37, 4635.
279. H. Miyaoka, Y. Hara, I. Shinohara, T. Kurokawa and Y. Yamada, Tetrahedron Lett., 2005, 46, 7945.
280. A. Lopez and W. H. Gerwick, Lipids, 1987, 22, 190.
281. T. Tsuzuki, K. Tanaka, S. Kuwahara and T. Miyazawa, Lipids, 2005, 40, 147.
282. E. Kurosawa, A. Fukuzawa and T. Irie, Tetrahedron Lett., 1973, 42, 4135.
283. H. Lee, H. Kim, T. Yoon, B. Kim, S. Kim, H.-D. Kim and D. Kim, J. Org. Chem., 2005, 70, 8723.
284. M. Maeda, T. Kodama, T. Tanaka, H. Yoshizumi, T. Takemoto, K. Nomoto and T. Fujita, Chem. Pharm. Bull., 1986, 34, 4892.
285. J. Clayden, F. E. Knowles and I. R. Baldwin, J. Am. Chem. Soc., 2005, 127, 2412.
286. J. Y. Su, Y. L. Zhong, L. M. Zeng, H. M. Wu and K. Ma, Phytochemistry, 1995, 40, 195.
287. J. Justicia, J. L. Oller-López, A. G. Campãna, J. E. Oltra, J. M. Cuerva, E. Buñuel and D. J. Cárdenas, J. Am. Chem. Soc., 2005, 127, 14911.
288. H. J. Park, Park, H. Y. Chung, J. Kim and J. S. Choi, J. Fish. Sci. Technol., 1999, 2, 1.
289. H. Park, M. Kurokawa, K. Shiraki, N. Nakamura, J. Choi and M. Hattori, Biol. Pharm. Bull., 2005, 28, 2258.
290. S. Tilvi, M. Majik and C. G. Naik, Eur. J. Mass Spectrom., 2005, 11, 345.
291. G. W. Zhang, X. Q. Ma, C. X. Zhang, J. Y. Su, W. C. Ye, X. Q. Zhang, X. S. Yao and L. M. Zeng, Helv. Chim. Acta, 2005, 88, 885.
292. S. N. Ayyad, Mansoura Sci. Bull., A: Chem., 2004, 31, 115.
293. V. Costantino, E. Fattorusso, C. Imperatore and A. Mangoni, Eur. J. Org. Chem., 2005, 2, 368.
294. C. Emura, R. Higuchi, T. Miyamoto and R. W. M. Van Soest, J. Org. Chem., 2005, 70, 3031.
295. V. Costantino, M. D'Esposito, E. Fattorusso, A. Mangoni, N. Basilico, S. Parapini and D. Taramelli, J. Med. Chem., 2005, 48, 7411.
296. T. N. Makarieva, A. G. Guzii, V. A. Denisenko, P. S. Dmitrenok, E. A. Santalova, E. V. Pokanevich, T. F. Molinski and V. A. Stonik, J. Nat. Prod., 2005, 68, 255.
297. L. Barbieri, V. Costantino, E. Fattorusso and A. Mangoni, J. Nat. Prod., 2005, 68, 1527.
298. T. N. Makarieva, V. A. Denisenko, P. S. Dmitrenok, A. G. Guzii, E. A. Santalova, V. A. Stonik, J. B. MacMillan and T. F. Molinski, Org. Lett., 2005, 7, 2897.
299. N. L. Segraves and P. Crews, J. Nat. Prod., 2005, 68, 118.
300. K. Warabi, T. Hamada, Y. Nakao, S. Matsunaga, H. Hirota, R. W. M. van Soest and N. Fusetani, J. Am. Chem. Soc., 2005, 127, 13262.
301. T. A. Mansoor, B. H. Bae, J. Hong, C. O. Lee, K. S. Im and J. H. Jung, Lipids, 2005, 40, 981.
302. M. Ishibashi, S. Takeuchi and J. Kobayashi, Tetrahedron Lett., 1993, 34, 3749.
303. M. Tsuda, T. Endo, M. Perpelescu, S. Yoshida, K. Watanabe, J. Fromont, Y. Mikami and J. Kobayashi, Tetrahedron, 2003, 59, 1137.
304. H. Mizutani, M. Watanabe and T. Honda, Synlett, 2005, 793.
305. S. C. Jain, R. Kumar, R. Goswami, M. K. Pandey, S. Khurana, L. Rohatgi and K. Gyanda, Pure Appl. Chem., 2005, 77, 185.
306. S. Tsukamoto, M. Takahashi, S. Matsunaga, N. Fusetani and R. W. M. van Soest, J. Nat. Prod., 2000, 63, 682.
307. A. P. Dobbs, A. Venturelli, L. A. Butler and R. J. Parker, Synlett, 2005, 4, 652.
308. A. Kawakami, T. Miyamoto, R. Higuchi, M. Kuwano and R. W. M. van Soest, Tetrahedron Lett., 2001, 42, 3335.
309. N. Sudhakar, A. Ravi Kumar, A. Prabhakar, B. Jagadeesh and B. Venkateswara Rao, Tetrahedron Lett., 2005, 46, 325.
310. P. Bhaket, K. Morris, C. S. Stauffer and A. Datta, Org. Lett., 2005, 7, 875.
311. I. Kuroda, M. Musman, I. I. Ohtani, T. Ichiba, J. Tanaka, D. G. Gravalos and T. Higa, J. Nat. Prod., 2002, 65, 1505.
312. V. Ledroit, C. Debitus, C. Lavaud and G. Massiot, Tetrahedron Lett., 2003, 44, 225.
313. R. G. Linington, M. Robertson, A. Gauthier, B. B. Findlay, R. van Soest and R. J. Andersen, Org. Lett., 2002, 4, 4089.
314. J. Sun, X. Han and B. Yu, Synlett, 2005, 437.
315. K. Watanabe, Y. Tsuda, M. Hamada, M. Omori, G. Mori, K. Iguchi, H. Naoki, T. Fujita and R. W. M. Van Soest, J. Nat. Prod., 2005, 68, 1001.
316. M. L. Lerch, M. K. Harper and D. J. Faulkner, J. Nat. Prod., 2003, 66, 667.
317. B. W. Gung, C. Gibeau and A. Jones, Tetrahedron: Asymmetry, 2005, 16, 3107.
318. H. Tada and F. Yasuda, Chem. Lett., 1984, 779.
319. N. Fusetani, M. Sugano, S. Matsunaga and K. Hashimoto, Tetrahedron Lett., 1987, 28, 4311.
320. S. López, F. Fernández-Trillo, P. Midón, L. Castedo and C. Saá, J. Org. Chem., 2005, 70, 6346.
321. T. Yosief, A. Rudi, Y. Wolde-ab and Y. Kashman, J. Nat. Prod., 1998, 61, 491.
322. A. Fontana, G. d'Ippolito, L. D'Souza, E. Mollo, P. S. Parameswaram and G. Cimino, J. Nat. Prod., 2001, 64, 131.
323. C. Xu, J. M. Raible and P. H. Dussault, Org. Lett., 2005, 7, 2509.
324. N. Sata, H. Abinsay, W. Y. Yoshida, F. D. Horgen, N. Sitachitta, M. Kelly and P. J. Scheuer, J. Nat. Prod., 2005, 68, 1400.
325. M. Holzwarth, J. M. Trendel, P. Albrecht, A. Maier and W. Michaelis, J. Nat. Prod., 2005, 68, 759.
326. R. A. Epifanio, L. S. Pinheiro and N. C. Alves, J. Braz. Chem. Soc., 2005, 16, 1367.
327. R. J. Capon, S. Singh, S. Ali and S. Sotheeswaran, Aust. J. Chem., 2005, 58, 18.
328. F. Berrué, O. P. Thomas, R. Fernández and P. Amade, J. Nat. Prod., 2005, 68, 547.
329. F. Berrué, O. P. Thomas, C. F. L. Bon, F. Reyes and P. Amade, Tetrahedron, 2005, 61, 11843.
330. C. Campagnuolo, E. Fattorusso, A. Romano, O. Taglialatela-Scafati, N. Basilico, S. Parapini and D. Taramelli, Eur. J. Org. Chem., 2005, 23, 5077.
331. D. B. Stierle and D. J. Faulkner, J. Org. Chem., 1980, 45, 3396.
332. M. Akiyama, Y. Isoda, M. Nishimoto, A. Kobayashi, D. Togawa, N. Hirao, A. Kuboki and S. Ohira, Tetrahedron Lett., 2005, 46, 7483.
333. A. S. Ratnayake, R. A. Davis, M. K. Harper, C. A. Veltri, C. D. Andjelic, L. R. Barrows and C. M. Ireland, J. Nat. Prod., 2005, 68, 104.
334. A. C. Granato, J. H. H. L. de Oliveira, M. H. R. Seleghim, R. G. S. Berlinck, M. L. Macedo, A. G. Ferreira, R. M. da Rocha, E. Hajdu, S. Peixinho, C. O. Pessoa, M. O. Moraes and B. C. Cavalcanti, Quim. Nova, 2005, 28, 192.
335. S. Cao, C. Foster, M. Brisson, J. S. Lazo and D. G. I. Kingston, Bioorg. Med. Chem., 2005, 13, 999.
336. N. Sata, M. A. Galario, N. Sitachitta, P. J. Scheuer and M. Kelly, J. Nat. Prod., 2005, 68, 262.
337. R. H. Cichewicz, F. A. Valeriote and P. Crews, Org. Lett., 2004, 6, 1951.
338. G. R. Pettit, J. Xu, J. Chapuis, R. K. Pettit, L. P. Tackett, D. L. Doubek, J. N. A. Hooper and J. M. Shmidt, J. Med. Chem., 2004, 47, 1149.
339. X. Jiang, J. García-Fortanet and J. K. De Brabander, J. Am. Chem. Soc., 2005, 127, 11254.
340. M. E. Green, J. C. Rech and P. E. Floreancig, Org. Lett., 2005, 7, 4117.
341. S. Kanazawa, N. Fusetani and S. Matsunaga, Tetrahedron Lett., 1993, 34, 1065.
342. N. Cramer, S. Laschat, A. Baro, H. Schwalbe and C. Richter, Angew. Chem., Int. Ed., 2005, 44, 820.
343. N. Fusetani, T. Sugawara, S. Matsunaga and H. Hirota, J. Org. Chem., 1991, 56, 4971.
344. S. Nishimura, S. Matsunaga, M. Yoshida, H. Hirota, S. Yokoyama and N. Fusetani, Bioorg. Med. Chem., 2005, 13, 449.
345. P. T. Northcote, J. W. Blunt and M. H. G. Munro, Tetrahedron Lett., 1991, 32, 6411.
346. M. E. Bordeleau, J. Mathews, J. Wojnar, L. Linquist, O. Novac, E. Janowsky, N. Sonenburg, P. Northcote, P. Teesdale-Spittle and J. Pelletier, Proc. Natl. Acad. Sci. U. S. A., 2005, 102, 10460.
347. W. K. Low, Y. J. Dang, T. Schneider-Poetsch, Z. G. Shi, N. S. Choi, W. C. Merrick, D. Romo and J. O. Liu, Mol. Cell, 2005, 20, 709.
348. T. Araki, S. Matsunaga and N. Fusetani, Biosci., Biotechnol., Biochem., 2005, 69, 1318.
349. N. Kotoku, L. Cao, S. Aoki and M. Kobayashi, Heterocycles, 2005, 65, 563.
350. T. Hamada, T. Sugawara, S. Matsunaga and N. Fusetani, Tetrahedron Lett., 1994, 35, 719.
351. T. Hamada, T. Sugawara, S. Matsunaga and N. Fusetani, Tetrahedron Lett., 1994, 35, 609.
352. T. Hamada, S. Matsunaga, G. Yano and N. Fusetani, J. Am. Chem. Soc., 2005, 127, 110.
353. K. C. Nicolaou, D. Schlawe, D. W. Kim, D. A. Longbottom, R. G. de Noronha, D. E. Lizos, R. R. Manam and D. J. Faulkner, Chem.–Eur. J., 2005, 11, 6197.
354. A. Randazzo, G. Bifulco, C. Giannini, M. Bucci, C. Debitus, G. Cirino and L. Gomez-Paloma, J. Am. Chem. Soc., 2001, 123, 10870.
355. K. C. Nicolaou, D. W. Kim, D. Schlawe, D. E. Lizos, R. G. de Noronha and D. A. Longbottom, Angew. Chem., Int. Ed., 2005, 44, 4925.
356. G. R. Pettit and R. Tan, J. Nat. Prod., 2005, 68, 60.
357. D. E. Williams, B. O. Patrick, H. W. Behrisch, R. Van Soest, M. Roberge and R. J. Andersen, J. Nat. Prod., 2005, 68, 327.
358. G. R. Pettit, J. Xu, A. Dorsaz and M. D. Williams, Bioorg. Med. Chem. Lett., 1995, 5, 1339.
359. A. Napolitano, I. Bruno, R. Riccio and L. Gomez-Paloma, Tetrahedron, 2005, 61, 6808.
360. A. Zampella, M. V. D'Auria, L. Gomez-Paloma, A. Casapullo, L. Minale, C. Debitus and Y. Henin, J. Am. Chem. Soc., 1996, 118, 6202.
361. A. Zampella, R. D'Orsi, V. Sepe, A. Casapullo, M. C. Monti and M. V. D'Auria, Org. Lett., 2005, 7, 3585.
362. N. Oku, A. G. Benson Krishnamoorthy, R. L. Ferguson, M. Z. Lipton, L. R. Phillips, K. R. Gustafson and J. B. McMahon, J. Org. Chem., 2005, 70, 6842.
363. P. W. Ford, K. R. Gustafson, T. C. McKee, N. Shigematsu, L. K. Maurizi, L. K. Pannell, D. E. Williams, E. D. de Silva and P. Lassota, J. Am. Chem. Soc., 1999, 121, 5899.
364. K. Makino, E. Nagata and Y. Hamada, Tetrahedron Lett., 2005, 46, 6827.
365. N. Oku, K. R. Gustafson, L. K. Cartner, J. A. Wilson, N. Shigamatsu, S. Hess, L. K. Pannell, M. R. Boyd and J. B. McMahon, J. Nat. Prod., 2004, 67, 1407.
366. D. E. Williams, P. Austin, A. R. Diaz-Marrero, R. Van Soest, T. Matainaho, C. D. Roskelley, M. Roberge and R. J. Andersen, Org. Lett., 2005, 7, 4173.
367. P. Phuwapraisirisan, S. Matsunaga and N. Fusetani, Org. Lett., 2005, 7, 2233.
368. S. Tsukamoto, K. Koimaru and K. Ohta, Mar. Drugs, 2005, 3, 29.
369. G. R. Pettit, Z. A. Chicaz, F. Gao, C. L. Herald, M. R. Boyd, J. M. Schmidt and J. N. A. Hooper, J. Org. Chem., 1993, 58, 1302.
370. R. K. Pettit, T. Woyke, S. Pon, Z. A. Cichacz, G. R. Pettit and C. L. Herald, Med. Mycol., 2005, 43, 453.
371. V. A. Klenchin, R. King, J. Tanaka, G. Marriott and I. Rayment, Chem. Biol., 2005, 12, 287.
372. N. Takada, H. Sato, K. Suenaga, H. Arimoto, K. Yamada, K. Ueda and D. Uemura, Tetrahedron Lett., 1999, 40, 6309.
373. T. R. Hoye and J. Wang, J. Am. Chem. Soc., 2005, 127, 6950.
374. M. R. Rao and D. J. Faulkner, J. Nat. Prod., 2002, 65, 386.
375. C. S. Barry, N. Bushby, J. P. H. Charmant, J. D. Elsworth, J. R. Harding and C. L. Willis, Chem. Commun., 2005, 5097.
376. M. S. Agrawal and B. F. Bowden, Mar. Drugs, 2005, 3, 9.
377. B. Carte and D. J. Faulkner, Tetrahedron, 1981, 37, 2335.
378. Y. M. Xu, R. K. Johnson and S. M. Hecht, Bioorg. Med. Chem., 2005, 13, 657.
379. R. Kazlauskas, R. O. Lidgard, P. T. Murphy and R. J. Wells, Tetrahedron Lett., 1980, 21, 2277.
380. R. Kazlauskas, R. O. Lidgard, P. T. Murphy, R. J. Wells and J. F. Blount, Aust. J. Chem., 1981, 34, 765.
381. E. O. Pordesimo and F. J. Schmitz, J. Org. Chem., 1990, 55, 4704.
382. M. S. Butler, T. K. Lim, R. J. Capon and L. S. Hammond, Aust. J. Chem., 1991, 44, 287.
383. E. A. Couladouros, E. N. Pitsinos, V. I. Moutsos and G. Sarakinos, Chem.–Eur. J., 2005, 11, 406.
384. P. Sauleau, P. Retailleau, J. Vacelet and M.-L. Bourguet-Kondracki, Tetrahedron, 2005, 61, 955.
385. A. Ardá, J. Rodríguez, R. M. Nieto, C. Bassarello, L. Gomez-Paloma, G. Bifulco and C. Jiménez, Tetrahedron, 2005, 61, 10093.
386. R. J. Capon, D. Vuong, E. Lacey and J. H. Gill, J. Nat. Prod., 2005, 68, 179.
387. R. J. Capon, D. Vuong, M. McNally, T. Peterle, N. Trotter, E. Lacey and J. H. Gill, Org. Biomol. Chem., 2005, 3, 118.
388. H. Suzuki, K. Shindo, A. Ueno, T. Miura, M. Takei, M. Sakakibara, H. Fukamachi, J. Tanaka and T. Higa, Bioorg. Med. Chem. Lett., 1999, 9, 1361.
389. R. A. Fairhurst, D. Janus and A. Lawrence, Org. Lett., 2005, 7, 4697.
390. J. G. Ondeyka, K. B. Herath, H. Jayasuriya, J. D. Polishook, G. F. Bills, A. W. Dombrowski, M. Mojena, G. Koch, J. DiSalvo, J. DeMartino, Z. Guan, W. Nanakorn and C. Morenberg, Mol. Diversity, 2005, 9, 123.
391. M. Tsuda, K. Hirano and J. Kobayashi, Tetrahedron Lett., 1999, 40, 4819.
392. S. P. Romeril, V. Lee, J. E. Baldwin and T. D. W. Claridge, Tetrahedron, 2005, 61, 1127.
393. H. Ishiyama, M. Tsuda, T. Endo and J. Kobayashi, Molecules, 2005, 10, 312.
394. R. A. Keyzers, C. E. Arendse, D. T. Hendricks, T. Samaai and M. T. Davies-Coleman, J. Nat. Prod., 2005, 68, 506.
395. G. Lang, A. Pinkert, J. W. Blunt and M. H. G. Munro, J. Nat. Prod., 2005, 68, 1796.
396. N. K. Utkina, A. E. Makarchenko and V. A. Denisenko, J. Nat. Prod., 2005, 68, 1424.
397. N. L. Segraves and P. Crews, J. Nat. Prod., 2005, 68, 1484.
398. S. Rubnov, C. Chevallier, O. Thoison, C. Debitus, O. Laprevote, D. Grénard and T. Sévenet, Nat. Prod. Res., 2005, 19, 75.
399. M. Tsuda, Y. Takahashi, J. Fromont, Y. Mikami and J. Kobayashi, J. Nat. Prod., 2005, 68, 1277.
400. B. Q. Bao, Q. S. Sun, X. S. Yao, J. K. Hong, C. O. Lee, C. J. Sim, K. S. Im and J. H. Jung, J. Nat. Prod., 2005, 68, 711.
401. K. B. Oh, W. Mar, S. Kim, J. Y. Kim, M. N. Oh, J. G. Kim, D. Shin, C. J. Sim and J. Shin, Bioorg. Med. Chem. Lett., 2005, 15, 4927.
402. D. T. A. Youssef, J. Nat. Prod., 2005, 68, 1416.
403. Y. Iinuma, S. Kozawa, H. Ishiyama, M. Tsuda, E. Fukushi, J. Kawabata, J. Fromont and J. Kobayashi, J. Nat. Prod., 2005, 68, 1109.
404. V. K. Rao, N. Kasanah, S. Wahyuono, B. L. Tekwani, R. F. Schinazi and M. T. Hamann, J. Nat. Prod., 2004, 67, 1314.
405. A. Casapullo, G. Bifulco, I. Bruno and R. Riccio, J. Nat. Prod., 2000, 63, 447.
406. T. Kouko, K. Matsumura and T. Kawasaki, Tetrahedron, 2005, 61, 2309.
407. A. Aiello, M. D'Esposito, E. Fattorusso, M. Menna, W. E. G. Müller, S. Perovic-Ottstadt, H. Tsuruta, T. A. M. Gulder and G. Bringmann, Tetrahedron, 2005, 61, 7266.
408. A. R. Carroll, A. Ngo, R. J. Quinn, J. Redburn and J. N. A. Hooper, J. Nat. Prod., 2005, 68, 804.
409. N. B. Perry, L. Ettouati, M. Litaudon, J. W. Blunt and M. H. G. Munro, Tetrahedron, 1994, 50, 3987.
410. M. Simone, E. Erba, G. Damia, F. Vikhanskaya, A. M. Di Francesco, R. Riccardi, C. Bailly, C. Cuevas, J. M. F. Sousa-Faro and M. D'Incalci, Eur. J. Cancer, 2005, 41, 2366.
411. G. R. Pettit, J. C. Knight, J. C. Collins, D. L. Herald, R. K. Pettit, M. R. Boyd and V. G. Young, J. Nat. Prod., 2000, 63, 793.
412. C. Chan, R. Heid, S. Zheng, J. Guo, B. Zhou, T. Furuuchi and S. J. Danishefsky, J. Am. Chem. Soc., 2005, 127, 4596.
413. B. S. Davidson, Tetrahedron Lett., 1992, 33, 3721.
414. P. Magnus and K. S. Matthews, J. Am. Chem. Soc., 2005, 127, 12476.
415. J. W. Lane, Y. Chen and R. M. Williams, J. Am. Chem. Soc., 2005, 127, 12684.
416. K. Warabi, S. Matsunaga, R. W. M. van Soest and N. Fusetani, J. Org. Chem., 2003, 68, 2765.
417. A. Fürstner, M. M. Domostoj and B. Scheiper, J. Am. Chem. Soc., 2005, 127, 11620.
418. J. F. Hu, J. Peng, A. B. Kazi, M. Kelly and M. T. Hamann, J. Chem. Res., 2005, 7, 427.
419. E. Fattorusso and O. Taglialatela-Scafati, Tetrahedron Lett., 2000, 41, 9917.
420. G. Papeo, M. A. G. Z. Frau, D. Borghi and M. Varasi, Tetrahedron Lett., 2005, 46, 8635.
421. J. Patel, N. Pelloux-Léon, F. Minassian and Y. Vallée, J. Org. Chem., 2005, 70, 9081.
422. W. A. Gallimore, M. Kelly and P. J. Scheuer, J. Nat. Prod., 2005, 68, 1420.
423. J. C. Braekman, D. Daloze, H. Tavares, E. Hajdu and R. W. M. van Soest, J. Nat. Prod., 2000, 63, 193.
424. Z. D. Aron and L. E. Overman, J. Am. Chem. Soc., 2005, 127, 3380.
425. R. G. S. Berlinck, J. C. Braekman, D. Daloze, I. Bruno, R. Riccio, S. Ferri, S. Spampinato and E. Speroni, J. Nat. Prod., 1993, 56, 1007.
426. L. E. Overman and Y. H. Rhee, J. Am. Chem. Soc., 2005, 127, 15652.
427. K. Ravinder, A. V. Reddy, T. V. Raju and Y. Venkateswarlu, ARKIVOC, 2005, 51.
428. S. Matsunaga, H. Kobayashi, R. W. M. van Soest and N. Fusetani, J. Org. Chem., 2005, 70, 1893.
429. F. C. Schroeder, T. R. Kau, P. A. Silver and J. Clardy, J. Nat. Prod., 2005, 68, 574.
430. S. N. Georgiades and J. Clardy, Org. Lett., 2005, 7, 4091.
431. A. Kijjoa, J. Bessa, R. Wattanadilok, P. Sawangwong, M. S. J. Nascimento, M. Pedro, A. M. S. Silva, G. Eaton, R. van Soest and W. Herz, Z. Naturforsch., B: Chem. Sci., 2005, 60, 904.
432. Y. Gopichand and F. J. Schmitz, Tetrahedron Lett., 1979, 3921.
433. G. M. König and A. D. Wright, Heterocycles, 1993, 36, 1351.
434. E. W. Rogers, M. F. de Oliveira, R. G. S. Berlinck, G. M. König and T. F. Molinski, J. Nat. Prod., 2005, 68, 891.
435. R. D. Encarnacion, E. Sandoval, J. Malmstrom and C. Christophersen, J. Nat. Prod., 2000, 63, 874.
436. T. Ogamino and S. Nishiyama, Tetrahedron Lett., 2005, 46, 1083.
437. R. J. Capon and N. S. Trotter, J. Nat. Prod., 2005, 68, 1689.
438. H. Wu, H. Nakamura, J. Kobayashi, Y. Ohizumi and Y. Hirata, Tetrahedron Lett., 1984, 25, 3719.
439. A. K. Bakkestuen, L. L. Gundersen, D. Petersen, B. T. Utenova and A. Vik, Org. Biomol. Chem., 2005, 3, 1025.
440. T. Hattori, K. Adachi and Y. Shizuri, J. Nat. Prod., 1997, 60, 411.
441. H. Nakamura, H. Wu, Y. Ohizumi and Y. Hirata, Tetrahedron Lett., 1984, 25, 2989.
442. I. S. Marcos, N. García, A. J. Sexmero, P. Basabe, D. Díez and J. G. Urones, Tetrahedron, 2005, 61, 11672.
443. E. Pérez-García, E. Zubía, M. J. Ortega and J. L. Carballo, J. Nat. Prod., 2005, 68, 653.
444. C. E. McNamara, L. Larsen, N. B. Perry, J. L. Harper, M. V. Berridge, E. W. Chia, M. Kelly and V. L. Webb, J. Nat. Prod., 2005, 68, 1431.
445. K. Ueda, T. Ueta, E. R. O. Siwu, M. Kita and D. Uemura, Chem. Lett., 2005, 34, 1530.
446. Y. Venkateswarlu, D. J. Faulkner, J. L. R. Steiner, E. Corcoran and J. Clardy, J. Org. Chem., 1991, 56, 6271.
447. A. Rudi, Y. Benayahu and Y. Kashman, Org. Lett., 2004, 6, 4013.
448. B. S. Olson and D. Trauner, Synlett, 2005, 4, 700.
449. H. Liu, M. Namikoshi, K. Akano, H. Kobayashi, H. Nagai and X. Yao, J. Asian Nat. Prod. Res., 2005, 7, 661.
450. E. Goclik, G. M. König, A. D. Wright and R. Kaminsky, J. Nat. Prod., 2000, 63, 1150.
451. J. H. Kwak, F. J. Schmitz and M. Kelly, J. Nat. Prod., 2000, 63, 1153.
452. L. Yang, D. E. Williams, A. Mui, C. Ong, G. Krystal, R. van Soest and R. J. Andersen, Org. Lett., 2005, 7, 1073.
453. S. S. Nasu, B. K. S. Yeung, M. T. Hamann, P. J. Scheuer, M. Kelly-Borges and K. Goin, J. Org. Chem., 1995, 60, 7290.
454. E. J. Alvarez-Manzaneda, R. Chahboun, I. B. Pérez, E. Cabrera, E. Alvarez and R. Alvarez-Manzaneda, Org. Lett., 2005, 7, 1477.
455. G. Cimino, S. De Stefano and L. Minale, Tetrahedron, 1973, 29, 2565.
456. C. J. Davis, T. E. Hurst, A. M. Jacob and C. J. Moody, J. Org. Chem., 2005, 70, 4414.
457. Y. Letourneux, J. M. Brunel, R. Fernandez, M. Dherbomez and C. Debitus, Heterocycl. Commun., 2005, 11, 291.
458. M. J. Martín, F. Berrué, P. Amade, R. Fernández, A. Francesch, F. Reyes and C. Cuevas, J. Nat. Prod., 2005, 68, 1554.
459. A. M. Piggott and P. Karuso, Molecules, 2005, 10, 1292.
460. H. Ishiyama, A. Hashimoto, J. Fromont, Y. Hoshino, Y. Mikami and J. Kobayashi, Tetrahedron, 2005, 61, 1101.
461. R. H. Cichewicz, L. J. Clifford, P. R. Lassen, X. L. Cao, T. B. Freedman, L. A. Nafie, J. D. Deschamps, V. A. Kenyon, J. R. Flanary, T. R. Holman and P. Crews, Bioorg. Med. Chem., 2005, 13, 5600.
462. V. J. Paul, Y. Seo, K. W. Cho, J. R. Rho, J. Shin and P. R. Bergquist, J. Nat. Prod., 1997, 60, 1115.
463. A. Rudi, Y. Benayahu and Y. Kashman, J. Nat. Prod., 2005, 68, 280.
464. H. Shimogawa, T. Teruya, K. Suenaga and H. Kigoshi, Bull. Chem. Soc. Jpn., 2005, 78, 1345.
465. A. Rudi, Y. Erez, Y. Benayahu and Y. Kashman, Tetrahedron Lett., 2005, 46, 8613.
466. M. L. Ciavatta, A. Fontana, S. Puliti, G. Scognamiglio and G. Cimino, Tetrahedron, 1999, 55, 12629.
467. M. L. Ciavatta, M. Gavagnin, E. Manzo, R. Puliti, C. A. Mattia, L. Mazzarella, G. Cimino, J. S. Simpson and M. J. Garson, Tetrahedron, 2005, 61, 8049.
468. G. Cimino, S. De Stefano, A. Guerriero and L. Minale, Tetrahedron Lett., 1975, 3723.
469. H. Gaspar, M. Gavagnin, G. Calado, F. Castelluccio, E. Mollo and G. Cimino, Tetrahedron, 2005, 61, 11032.
470. M. Tischler, R. J. Andersen, M. I. Choudhary and J. Clardy, J. Org. Chem., 1991, 56, 42.
471. M. Kolympadi, M. Liapis and V. Ragoussis, Tetrahedron, 2005, 61, 2003.
472. S. Cao, C. Foster, J. S. Lazo and D. G. I. Kingston, Bioorg. Med. Chem., 2005, 13, 5094.
473. M. Li, L. Li, Z. Deng, Y. Qiu and W. Lin, Bopuxue Zazhi, 2004, 21, 323.
474. Z. G. Yu, K. S. Bi and Y. W. Guo, Helv. Chim. Acta, 2005, 88, 1004.
475. G. R. Pettit, R. Tan and Z. A. Cichacz, J. Nat. Prod., 2005, 68, 1253.
476. D. T. A. Youssef, L. A. Shaala and S. Emara, J. Nat. Prod., 2005, 68, 1782.
477. G. Cimino, S. De Stefano, L. Minale and E. Fattorusso, Tetrahedron, 1972, 28, 333.
478. H. J. Choi, Y. H. Choi, S. B. Yee, E. Im, J. H. Jung and N. D. Kim, Mol. Carcinog., 2005, 44, 162.
479. M. R. Kernan, D. J. Faulkner, L. Parkanyi, J. Clardy, M. S. de Carvalho and R. S. Jacobs, Experientia, 1989, 45, 388.
480. M. S. Buchanan, A. Edser, G. King, J. Whitmore and R. J. Quinn, J. Nat. Prod., 2001, 64, 300.
481. P. Basabe, S. Delgado, I. S. Marcos, D. Diez, A. Diego, M. De Román and J. G. Urones, J. Org. Chem., 2005, 70, 9480.
482. T. A. Mansoor, J. Hong, C. O. Lee, S. J. Bae, K. S. Im and J. H. Jung, J. Nat. Prod., 2005, 68, 331.
483. L. Li, Z. Deng, H. Fu, J. Li, W. Lin and P. Proksch, J. Asian Nat. Prod. Res., 2005, 7, 115.
484. P. Sauleau and M.-L. Bourguet-Kondracki, Steroids, 2005, 70, 954.
485. X. C. Huang, Y. W. Guo, E. Mollo and G. Cimino, Helv. Chim. Acta, 2005, 88, 281.
486. A. Mandeau, C. Debitus, M. F. Ariès and B. David, Steroids, 2005, 70, 873.
487. H. Mitome, N. Shirato, A. Hoshino, H. Miyaoka, Y. Yamada and R. W. M. Van Soest, Steroids, 2005, 70, 63.
488. A. Zampella, R. D'Orsi, V. Sepe, S. De Marino, N. Borbone, A. Valentin, C. Debitus, F. Zollo and M. V. D'Auria, Eur. J. Org. Chem., 2005, 20, 4359.
489. D. Xiao, X. Peng, S. Deng, W. Ma and H. Wu, Chin. J. Org. Chem., 2005, 25, 1606.
490. J. S. Sandler, S. L. Forsburg and D. J. Faulkner, Tetrahedron, 2005, 61, 1199.
491. S. A. Tang, Z. W. Deng, J. Li, H. Z. Fu, Y. H. Pei, S. Zhang and W. H. Lin, Chin. Chem. Lett., 2005, 16, 353.
492. C. F.-L. Bon, F. Berrué, O. P. Thomas, F. Reyes and P. Amade, J. Nat. Prod., 2005, 68, 1284.
493. H. F. Dai, R. A. Edrada, R. Ebel, M. Nimtz, V. Wray and P. Proksch, J. Nat. Prod., 2005, 68, 1231.
494. E. W. Rogers and T. F. Molinski, J. Nat. Prod., 2005, 68, 450.
495. G. Q. Li, X. Li, Z. W. Deng, H. S. Guan and W. H. Lin, Chin. Chem. Lett., 2005, 16, 494.
496. N. Fusetani, T. Toyoda, N. Asai, S. Matsunaga and T. Maruyama, J. Nat. Prod., 1996, 59, 796.
497. N. Alam, B. H. Bae, J. Hong, C. O. Lee, K. S. Im and J. H. Jung, J. Nat. Prod., 2001, 64, 1059.
498. M. Kita, M. Kitamura, T. Koyama, T. Teruya, H. Matsumoto, Y. Nakano and D. Uemura, Tetrahedron Lett., 2005, 46, 8583.
499. L. Quijano, F. Cruz, I. Navarrete, P. Gomez and T. Rios, Lipids, 1994, 29, 731.
500. A. Han, J. Song, D. S. Jang, H. Min, S. K. Lee and E. Seo, Arch. Pharm. Res., 2005, 28, 290.
501. P. Muralidhar, M. M. Kumar, N. Krishna, C. B. Rao and D. V. Rao, Chem. Pharm. Bull., 2005, 53, 168.
502. X. He, S. Yan, L. Zeng and J. Su, Zhongshan Daxue Xuebao, Ziran Kexueban, 2005, 44, 113.
503. C. Subrahmanyam, S. Ratnar Kumar and G. Damodar Reddy, Indian J. Chem., Sect. B, 2005, 44, 2186.
504. J.-Y. Su, Y.-Y. Kuang, L.-M. Zeng and H. Li, J. Asian Nat. Prod. Res., 2005, 7, 107.
505. V. Anjaneyulu and P. Radhika, Indian J. Chem., Sect. B, 1999, 38, 457.
506. P. Radhika, P. R. Rao, J. Archana and N. K. Rao, Biol. Pharm. Bull., 2005, 28, 1311.
507. C. A. Ospina, A. D. Rodríguez, J. A. Sánchez, E. Ortega-Barria, T. L. Capson and A. M. S. Mayer, J. Nat. Prod., 2005, 68, 1519.
508. J.-H. Su, A. F. Ahmed, P.-J. Sung, Y.-C. Wu and J.-H. Sheu, J. Nat. Prod., 2005, 68, 1651.
509. A. F. Ahmed, Y.-H. Kuo, C.-F. Dai and J.-H. Sheu, J. Nat. Prod., 2005, 68, 1208.
510. H.-C. Huang, C.-H. Chao, J.-H. Liao, M. Y. Chiang, C.-F. Dai, Y.-C. Wu and J.-H. Sheu, Tetrahedron Lett., 2005, 46, 7711.
511. S. P. Garzón, A. D. Rodríguez, J. A. Sánchez and E. Ortega-Barria, J. Nat. Prod., 2005, 68, 1354.
512. A. A. H. El-Gamal, E.-P. Chiu, C.-H. Li, S.-Y. Cheng, C.-F. Dai and C.-Y. Duh, J. Nat. Prod., 2005, 68, 1749.
513. S.-H. Qi, S. Zhang, X. Li and Q.-X. Li, J. Nat. Prod., 2005, 68, 1288.
514. N. S. Reddy, J. K. Reed, R. E. Longley and A. E. Wright, J. Nat. Prod., 2005, 68, 248.
515. A. Ata, H. Y. Win, D. Holt, P. Holloway, E. P. Segstro and G. S. Jayatilake, Helv. Chim. Acta, 2004, 87, 1090.
516. C. Duque, M. Puyana, G. Narváez, O. Osorno, N. Hara and Y. Fujimoto, Tetrahedron, 2004, 60, 10627.
517. I. I. Rodríguez, Y.-P. Shi, O. J. Garciá, A. D. Rodríguez, A. M. S. Mayer, J. A. Sánchez, E. Ortega-Barria and J. González, J. Nat. Prod., 2004, 67, 1672.
518. A. D. Rodríguez, personal communication, 2006.
519. T. Ferns and R. G. Kerr, Tetrahedron, 2005, 61, 12358.
520. A. A. H. El-Gamal, S.-K. Wang, C.-F. Dai, I.-G. Chen and C.-Y. Duh, J. Nat. Prod., 2005, 68, 74.
521. J. Y. Su, R. L. Yang, Y. Y. Kuang and L. M. Zeng, J. Nat. Prod., 2000, 63, 1543.
522. C.-X. Zhang, S.-J. Yan, G.-W. Zhang, W.-G. Lu, J.-Y. Su, L.-M. Zeng, L.-Q. Gu, X.-P. Yang and Y.-J. Lian, J. Nat. Prod., 2005, 68, 1087.
523. R. Jia, Y.-W. Guo, E. Mollo and G. Cimino, Helv. Chim. Acta, 2005, 88, 1028.
524. M. Gutiérrez, T. L. Capson, H. M. Guzmán, J. González, E. Ortega-Barria, E. Quiñoa and R. Riguera, J. Nat. Prod., 2005, 68, 614.
525. G. Li, Y. Zhang, Z. Deng, L. van Ofwegen, P. Proksch and W. Lin, J. Nat. Prod., 2005, 68, 649.
526. S. W. Yin, Y. P. Shi, X. M. Li and B. G. Wang, Chin. Chem. Lett., 2005, 16, 1489.
527. A. F. Ahmed, R.-T. Shiue, G.-H. Wang, C.-F. Dai, Y.-H. Kuo and J.-H. Sheu, Tetrahedron, 2003, 59, 7337.
528. Y.-J. Tseng, A. F. Ahmed, C.-F. Dai, M. Y. Chiang and J.-H. Sheu, Org. Lett., 2005, 7, 3813.
529. M. Kobayashi and T. Hamaguchi, Chem. Pharm. Bull., 1988, 36, 3780.
530. Y.-L. Zhang, X.-L. Tang, G.-Q. Li and W.-H. Lin, Qingdao Keji Daxue Xuebao, Ziran Kexueban, 2005, 26, 215.
531. A. A. H. El-Gamal, S.-K. Wang and C.-Y. Duh, Org. Lett., 2005, 7, 2023.
532. A. A. H. El-Gamal, S.-K. Wang and C.-Y. Duh, Tetrahedron Lett., 2005, 46, 6095.
533. J. Marrero, A. D. Rodríguez and C. L. Barnes, Org. Lett., 2005, 7, 1877.
534. T. Iwagawa, K. Babazono, M. Nakatani, M. Doe, Y. Morimoto and K. Takemura, Heterocycles, 2005, 65, 607.
535. T. Iwagawa, N. Nishitani, M. Nakatani, M. Doe, Y. Morimoto and K. Takemura, J. Nat. Prod., 2005, 68, 31.
536. T. Iwagawa, N. Nishitani, M. Nakatani, M. Doe, Y. Morimoto and K. Takemura, J. Nat. Prod., 2005, 68, 818.
537. T. Iwagawa, K. Babazono, H. Okamura, M. Nakatani, M. Doe, Y. Morimoto, M. Shiro and K. Takemura, Heterocycles, 2005, 65, 2083.
538. T. Iwagawa, K. Babazono, H. Okamura, M. Nakatani, M. Doe, Y. Morimoto, M. Shiro and K. Takemura, Heterocycles, 2005, 65, 3093.
539. P.-J. Sung, W.-P. Hu, L.-S. Fang, T.-Y. Fan and J.-J. Wang, Nat. Prod. Res., 2005, 19, 689.
540. A. Hoshino, H. Mitome, S. Tamai, H. Takiyama and H. Miyaoka, J. Nat. Prod., 2005, 68, 1328.
541. T. Barsby and J. Kubanek, J. Nat. Prod., 2005, 68, 511.
542. Y.-C. Lin, Y.-L. Huang, A. T. Khalil, M.-H. Chen and Y.-C. Shen, Chem. Pharm. Bull., 2005, 53, 128.
543. S.-H. Qi, S. Zhang, Y.-M. Wen, Z.-H. Xiao and Q.-X. Li, Helv. Chim. Acta, 2005, 88, 2349.
544. J. J. Morales, D. Lorenzo and A. D. Rodríguez, J. Nat. Prod., 1991, 54, 1368.
545. M. T. Crimmins and J. M. Ellis, J. Am. Chem. Soc., 2005, 127, 17200.
546. L. Chill, N. Berrer, Y. Benayahu and Y. Kashman, J. Nat. Prod., 2005, 68, 19.
547. P. Bernardelli, O. M. Moradei, D. Friedrich, J. Yang, F. Gallou, B. P. Dyck, R. W. Doskotch, T. Lange and L. A. Paquette, J. Am. Chem. Soc., 2001, 123, 9021.
548. J.-H. Su, H.-C. Huang, C.-H. Chao, L.-Y. Yan, Y.-C. Wu, C.-C. Wu and J.-H. Shen, Bull. Chem. Soc. Jpn., 2005, 78, 877.
549. A. F. Ahmed, M.-H. Wu, G.-H. Wang, Y.-C. Wu and J.-H. Sheu, J. Nat. Prod., 2005, 68, 1051.
550. A. A. H. El-Gamal, C.-Y. Chiang, S.-H. Huang, S.-K. Wang and C.-Y. Duh, J. Nat. Prod., 2005, 68, 1336.
551. Y.-C. Shen, Y.-C. Lin, A. F. Ahmed and Y.-H. Kuo, Tetrahedron Lett., 2005, 46, 4793.
552. A. A. H. El-Gamal, S.-K. Wang and C.-Y. Duh, Tetrahedron Lett., 2005, 46, 4499.
553. G. G. Mellado, E. Zubía, M. J. Ortega and P. J. López-González, J. Nat. Prod., 2005, 68, 1111.
554. X. H. Yan and Y. W. Guo, Chin. Chem. Lett., 2005, 16, 356.
555. R. Jia, Y.-W. Guo, E. Mollo and G. Cimino, Nat. Prod. Res., 2005, 19, 789.
556. C.-H. Chao, L.-F. Huang, S.-L. Wu, J.-H. Su, H.-C. Huang and J.-H. Sheu, J. Nat. Prod., 2005, 68, 1366.
557. P. Jin, Z. Deng, Y. Pei, H. Fu, J. Li, L. van Ofwegen, P. Proksch and W. Lin, Steroids, 2005, 70, 487.
558. G. Li, Z. Deng, H. Guan, L. van Ofwegen, P. Proksch and W. Lin, Steroids, 2005, 70, 13.
559. G.-W. Zhang, X.-Q. Ma, H. Kurihara, C.-X. Zhang, X.-S. Yao, J.-Y. Su and L.-M. Zeng, Org. Lett., 2005, 7, 991.
560. W. Zhang, Y.-W. Guo, M. Gavagnin, E. Mollo and G. Cimino, Helv. Chim. Acta, 2005, 88, 87.
561. W. Zhang, G.-M. Yao and Y.-W. Guo, Acta Crystallogr., Sect. E, 2005, 61, o2884.
562. C. Subrahmanyam and S. R. Kumar, J. Chem. Res., Synop., 2000, 182.
563. J. Yang, S.-H. Qi, S. Zhang, J. Wu and Z.-H. Xiao, Chin. J. Chem., 2005, 23, 1218.
564. C.-H. Chao, L.-F. Huang, Y.-L. Yang, J.-H. Su, G.-H. Wang, M. Y. Chiang, Y.-C. Wu, C.-F. Dai and J.-H. Sheu, J. Nat. Prod., 2005, 68, 880.
565. C. B. Rao, K. V. Ramana, D. V. Rao, E. Fahy and D. J. Faulkner, J. Nat. Prod., 1988, 51, 954.
566. G.-W. Zhang, X.-Q. Ma, S.-J. Yan, L.-M. Zeng and J.-Y. Su, Gaodeng Xuexiao Huaxue Xuebao, 2005, 26, 81.
567. S. Qi, S. Zhang, J. Huang, Z. Xiao, J. Wu and Q. Li, Magn. Reson. Chem., 2005, 43, 266.
568. H. T. D'Armas, B. S. Mootoo and W. F. Reynolds, J. Nat. Prod., 2000, 63, 1669.
569. A. Rueda, E. Zubia, M. J. Ortega and J. Salva, Steroids, 2001, 66, 897.
570. H. Jayasuriya, K. B. Herath, J. G. Ondeyka, Z. Guan, R. P. Borris, S. Tiwari, W. de Jong, F. Chavez, J. Moss, D. W. Stevenson, H. T. Beck, M. Slattery, N. Zamora, M. Schulman, A. Ali, N. Sharma, K. MacNaul, N. Hayes, J. G. Menke and S. B. Singh, J. Nat. Prod., 2005, 68, 1247.
571. S. Cao, C. Foster, J. S. Lazo and D. G. I. Kingston, Bioorg. Med. Chem., 2005, 13, 5830.
572. H. Nagai, Kaiyo Seibutsu Seibun no Riyo, 2005, 106.
573. T. Honma, Y. Hasegawa, M. Ishida, H. Nagai, Y. Nagashima and K. Shiomi, Toxicon, 2005, 45, 33.
574. T. Honma, S. Minagawa, H. Nagai, M. Ishida, Y. Nagashima and K. Shiomi, Toxicon, 2005, 46, 768.
575. A. P. Il'ina, M. M. Monastyrnaya, I. N. Sokotun, T. A. Egorov, Y. A. Nazarenko, G. N. Likhatskaya and E. P. Kozlovskaya, Russ. J. Bioorg. Chem., 2005, 31, 34.
576. R. B. Cunha, A. N. C. Santana, P. C. Amaral, M. D. F. Carvalho, D. M. F. Carvalho, E. A. Cavalheiro, B. Maigret, C. A. O. Ricart, B. A. Cardi, M. V. Sousa and K. M. Carvalho, Toxicon, 2005, 45, 207.
577. A. J. Blackman and D. J. Matthews, Heterocycles, 1985, 23, 2829.
578. M. Ramirez-Osuna, D. Chavez, L. Hernandez, E. Molins, R. Somanathan and G. Aguirre, Molecules, 2005, 10, 295.
579. H. Kawashima, Lipids, 2005, 40, 627.
580. G. R. Pettit, Y. Tang and J. C. Knight, J. Nat. Prod., 2005, 68, 974.
581. R. J. Andersen, D. J. Faulkner, H. Cun-heng, G. D. Van Duyne and J. Clardy, J. Am. Chem. Soc., 1985, 107, 5492.
582. M. Vanhuyse, J. Kluza, C. Tardy, G. Otero, C. Cuevas, C. Bailly and A. Lansiaux, Cancer Lett., 2005, 221, 165.
583. C. M. Ireland and P. J. Scheuer, Science, 1979, 205, 922.
584. E. Manzo, M. L. Ciavatta, M. Gavagnin, E. Mollo, S. Wahidulla and G. Cimino, Tetrahedron Lett., 2005, 46, 465.
585. M. Cueto, L. D'Croz, J. L. Maté, A. San-Martín and J. Darias, Org. Lett., 2005, 7, 415.
586. J. E. Barbarow, A. K. Miller and D. Trauner, Org. Lett., 2005, 7, 2901.
587. J. E. Moses, R. M. Adlington, R. Rodriguez, S. J. Eade and J. E. Baldwin, Chem. Commun., 2005, 1687.
588. D. R. Zuidema, A. K. Miller, D. Trauner and P. B. Jones, Org. Lett., 2005, 7, 4959.
589. V. Di Marzo, R. R. Vardaro, L. De Petrocellis, G. Villani, R. Minei and G. Cimino, Experientia, 1991, 47, 1221.
590. D. R. Zuidema and P. B. Jones, J. Nat. Prod., 2005, 68, 481.
591. M. Gavagnin, E. Mollo, G. Cimino and J. Ortea, Tetrahedron Lett., 1996, 37, 4259.
592. D. W. Jeffery, M. V. Perkins and J. M. White, Org. Lett., 2005, 7, 1581.
593. D. C. Manker and D. J. Faulkner, Tetrahedron, 1987, 43, 3677.
594. A. Pathak, J. Aslaoui and C. Morin, J. Org. Chem., 2005, 70, 4184.
595. T. Maoka, Y. Fujiwara, K. Hashimoto and N. Akimoto, Chem. Pharm. Bull., 2005, 53, 1207.
596. J.-K. Seo, J. M. Crawford, K. L. Stone and E. J. Noga, Biochem. Biophys. Res. Commun., 2005, 338, 1998.
597. G. Bulaj, P. J. West, J. E. Garrett, M. Marsh, M.-M. Zhang, R. S. Norton, B. J. Smith, D. Yoshikami and B. M. Olivera, Biochemistry, 2005, 44, 7259.
598. M. B. Aguilar, E. López-Vera, J. S. Imperial, A. Falcón, B. M. Olivera and E. P. Heimer dela Cotera, Peptides, 2005, 26, 23.
599. M. C. V. Braga, K. Konno, F. C. V. Portaro, J. C. de Freitas, T. Yamane, B. M. Olivera and D. C. Pimenta, Toxicon, 2005, 45, 113.
600. S. Sudarslal, S. Majumdar, P. Ramasamy, R. Dhawan, P. P. Pal, M. Ramaswami, A. K. Lala, S. K. Sikdar, S. P. Sarma, K. S. Krishnan and P. Balaram, FEBS Lett., 2003, 553, 209.
601. S. P. Sarma, G. S. Kumar, S. Sudarslal, P. Iengar, P. Ramasamy, S. K. Sikdar, K. S. Krishnan and P. Balaram, Chem. Biodiversity, 2005, 2, 535.
602. T. Grkovic, D. R. Appleton and B. R. Copp, Chem. N. Z., 2005, 69, 12.
603. C. E. Kicklighter, S. Shabani, P. M. Johnson and C. D. Derby, Curr. Biol., 2005, 15, 549.
604. T. Dias, I. Brito, L. Moujir, N. Paiz, J. Darias and M. Cueto, J. Nat. Prod., 2005, 68, 1677.
605. E. Manzo, M. L. Ciavatta, M. Gavagnin, R. Puliti, E. Mollo, Y.-W. Guo, C. A. Mattia, L. Mazzarella and G. Cimino, Tetrahedron, 2005, 61, 7456.
606. M. Norte, A. G. González, F. Cataldo, M. L. Rodríguez and I. Brito, Tetrahedron, 1991, 47, 9411.
607. D. Awakura, K. Fujiwara and A. Murai, Chem. Lett., 1999, 461.
608. D. Iliopoulou, C. Vagias, C. Harvala and V. Roussis, Phytochemistry, 2002, 59, 111.
609. K. L. McPhail and M. T. Davies-Coleman, Nat. Prod. Res., 2005, 19, 449.
610. S. Tsukamoto, Y. Yamashita and T. Ohta, Mar. Drugs, 2005, 3, 22.
611. S. Suntornchashwej, N. Chaichit, M. Isobe and K. Suwanborirux, J. Nat. Prod., 2005, 68, 951.
612. M. Gavagnin, M. Carbone, M. Nappo, E. Mollo, V. Roussis and G. Cimino, Tetrahedron, 2005, 61, 617.
613. K. Suenaga, T. Shibata, N. Takada, H. Kigoshi and K. Yamada, J. Nat. Prod., 1998, 61, 515.
614. Y. Morimoto, Y. Nishikawa and M. Takaishi, J. Am. Chem. Soc., 2005, 127, 5806.
615. G. R. Pettit, Y. Kamano, H. Kizu, C. Dufresne, C. L. Herald, R. J. Bontems, J. M. Schmidt, F. E. Boettner and R. A. Nieman, Heterocycles, 1989, 28, 553.
616. M. A. Ali, R. B. Bates, Z. D. Crane, C. W. Dicus, M. R. Gramme, E. Hamel, J. Marcischak, D. S. Martinez, K. J. McClure, P. Nakkiew, G. R. Pettit, C. C. Stessman, B. A. Sufi and G. V. Yarick, Bioorg. Med. Chem., 2005, 13, 4138.
617. M. Gavagnin, M. Carbone, E. Mollo and G. Cimino, Tetrahedron Lett., 2003, 44, 1495.
618. E. J. Alvarez-Manzaneda, R. Chahboun, I. Barranco, E. C. Torres, E. Alvarez and R. Alvarez-Manzaneda, Tetrahedron Lett., 2005, 46, 5321.
619. V. Kulciţki, N. Ungur, M. Gavagnin, M. Carbone and G. Cimino, Eur. J. Org. Chem., 2005, 1816.
620. K. L. McPhail, M. T. Davies-Coleman and J. Starmer, J. Nat. Prod., 2001, 64, 1183.
621. C.-H. Li, S.-J. Da, X.-S. Chen, G.-L. Zhou, Z.-X. Xie and Y. Li, Huaxue Xuebao, 2005, 63, 2158.
622. T. P. Brady, S. H. Kim, K. Wen, C. Kim and E. A. Theodorakis, Chem.–Eur. J., 2005, 11, 7175.
623. J. E. Hochlowski, D. J. Faulkner, G. K. Matsumoto and J. Clardy, J. Org. Chem., 1983, 48, 1142.
624. A. Abad, C. Agulló, A. C. Cuñat and A. B. García, Tetrahedron, 2005, 61, 1961.
625. T. Miyamoto, K. Sakamoto, K. Arao, T. Komori, R. Higuchi and T. Sasaki, Tetrahedron, 1996, 52, 8187.
626. A. Fontana, P. Cavaliere, S. Wahidulla, C. G. Naik and G. Cimino, Tetrahedron, 2000, 56, 7305.
627. T. Teruya, K. Suenaga, S. Maruyama, M. Kurotaki and H. Kigoshi, Tetrahedron, 2005, 61, 6561.
628. J.-F. Biard, C. Roussakis, J.-M. Kornprobst, D. Gouiffes-Barbin, J.-F. Verbist, P. Cotelle, M. P. Foster, C. M. Ireland and C. Debitus, J. Nat. Prod., 1994, 57, 1336.
629. G. Zuber, M.-R. Goldsmith, T. D. Hopkins, D. N. Beratan and P. Wipf, Org. Lett., 2005, 7, 5269.
630. P. Wipf and T. D. Hopkins, Chem. Commun., 2005, 3421.
631. S. C. Lievens and T. F. Molinski, Org. Lett., 2005, 7, 2281.
632. A. Simon-Levert, A. Arrault, N. Bontemps-Subielos, C. Canal and B. Banaigs, J. Nat. Prod., 2005, 68, 1412.
633. L. K. Shubina, S. N. Fedorov, O. S. Radchenko, N. N. Balaneva, S. A. Kolesnikova, P. S. Dmitrenok, A. Bode, Z. Dong and V. A. Stonik, Tetrahedron Lett., 2005, 46, 559.
634. G. Guella, I. Mancini and F. Pietra, Helv. Chim. Acta, 1987, 70, 621.
635. A. Aiello, E. Fattorusso, P. Luciano, A. Mangoni and M. Menna, Eur. J. Org. Chem., 2005, 5024.
636. A. Aiello, E. Fattorusso, P. Luciano, A. Macho, M. Menna and E. Muñoz, J. Med. Chem., 2005, 48, 3410.
637. M. J. McKay, A. R. Carroll and R. J. Quinn, J. Nat. Prod., 2005, 68, 1776.
638. K. Ravinder, A. V. Reddy, P. Krishnaiah, P. Ramesh, S. Ramakrishna, H. Laatsch and Y. Venkateswarlu, Tetrahedron Lett., 2005, 46, 5475.
639. H. Liu, S. B. Pratasik, T. Nishikawa, T. Shida, K. Tachibana, T. Fujiwara, H. Nagai, H. Kobayashi and M. Namikoshi, Tetrahedron Lett., 2004, 45, 7015.
640. H. Liu, T. Fujiwara, T. Nishikawa, Y. Mishima, H. Nagai, T. Shida, K. Tachibana, H. Kobayashi, R. E. P. Mangindaan and M. Namikoshi, Tetrahedron, 2005, 61, 8611.
641. S. Malla Reddy, M. Srinivasulu, N. Satyanarayana, A. K. Kondapi and Y. Venkateswarlu, Tetrahedron, 2005, 61, 9242.
642. A. J. Blackman, C. P. Li, D. C. R. Hockless, B. W. Skelton and A. H. White, Tetrahedron, 1993, 49, 8645.
643. J. F. Baird, S. Guyot, C. Roussakis, J. F. Verbist, J. Vercauteren, J. F. Weber and K. Boukef, Tetrahedron Lett., 1994, 35, 2691.
644. H. H. Issa, J. Tanaka, R. Rachmat, A. Setiawan, A. Trianto and T. Higa, Mar. Drugs, 2005, 3, 78.
645. E. W. Schmidt, J. T. Nelson, D. A. Rasko, S. Sudek, J. A. Eisen, M. G. Haygood and J. Ravel, Proc. Natl. Acad. Sci. U. S. A., 2005, 102, 7315.
646. P. F. Long, W. C. Dunlap, C. N. Battershill and M. Jaspars, ChemBioChem, 2005, 6, 1760.
647. L. J. Perez and D. J. Faulkner, J. Nat. Prod., 2003, 66, 247.
648. S.-L. You and J. W. Kelly, Tetrahedron, 2005, 61, 241.
649. Y. Yonezawa, N. Tani and C.-G. Shin, Bull. Chem. Soc. Jpn., 2005, 78, 1492.
650. A. Rudi, L. Chill, M. Aknin and Y. Kashman, J. Nat. Prod., 2003, 66, 575.
651. S.-L. You and J. W. Kelly, Tetrahedron Lett., 2005, 46, 2567.
652. S. Kumar-Roiné, M. Frostin, A. Al-Mourabit, A.-G. Duigou, J. Pusset, S. Ali, M. Sauvain, S. Sotheeswaran and D. Laurent, ACGC Chem. Res. Commun., 2005, 18, 25.
653. A. J. Freyer, A. D. Patil, L. Killmer, N. Troupe, M. Mentzer, B. Carte, L. Faucette and R. K. Johnson, J. Nat. Prod., 1997, 60, 986.
654. B. M. Trost and D. R. Fandrick, Org. Lett., 2005, 7, 823.
655. A. D. Patil, A. J. Freyer, R. Reichwein, B. Carte, L. B. Killmer, L. Faucette, R. K. Johnson and D. J. Faulkner, Tetrahedron Lett., 1997, 38, 363.
656. H. Abe, S. Aoyagi and C. Kibayashi, J. Am. Chem. Soc., 2005, 127, 1473.
657. S. Dutta, H. Abe, S. Aoyagi, C. Kibayashi and K. S. Gates, J. Am. Chem. Soc., 2005, 127, 15004.
658. F. Kong and D. J. Faulkner, Tetrahedron Lett., 1991, 32, 3667.
659. J. Kubanek, D. E. Williams, E. D. de Silva, T. Allen and R. J. Andersen, Tetrahedron Lett., 1995, 36, 6189.
660. H. Tsuneki, Y. You, N. Toyooka, T. Sasaoka, H. Nemoto, J. A. Dani and I. Kimura, Biol. Pharm. Bull., 2005, 28, 611.
661. H. Kang and W. Fenical, J. Org. Chem., 1997, 62, 3254.
662. A. Hamasaki, J. M. Zimpleman, I. Hwang and D. L. Boger, J. Am. Chem. Soc., 2005, 127, 10767.
663. S. Faivre, S. Chièze, C. Delbaldo, N. Ady-Vago, C. Guzman, L. Lopez-Lazaro, S. Lozahic, J. Jimeno, F. Pico, J. P. Armand, J. A. L. Martin and E. Raymond, J. Clin. Oncol., 2005, 23, 7871.
664. E. F. A. Brandon, R. D. van Ooijen, R. W. Sparidans, L. L. Lázaro, A. J. R. Heck, J. H. Beijnen and J. H. M. Schellens, J. Mass Spectrom., 2005, 40, 821.
665. J. Fayette, I. R. Coquard, L. Alberti, D. Ranchère, H. Boyle and J.-Y. Blay, Oncologist, 2005, 10, 827.
666. P. Allavena, M. Signorelli, M. Chieppa, E. Erba, G. Bianchi, F. Marchesi, C. O. Olimpio, C. Bonardi, A. Garbi, A. Lissoni, F. de Braud, J. Jimeno and M. D'Incalci, Cancer Res., 2005, 65, 2964.
667. T. Hamada, M. Asanuma, T. Ueki, F. Hayashi, N. Kobayashi, S. Yokoyama, H. Michibata and H. Hirota, J. Am. Chem. Soc., 2005, 127, 4216.
668. N. P. Mischenko, S. A. Fedoreyev, N. D. Pokhilo, V. P. Anufriev, V. A. Denisenko and V. P. Glazunov, J. Nat. Prod., 2005, 68, 1390.
669. J. R. Rho and Y. H. Kim, Bull. Korean Chem. Soc., 2005, 26, 1457.
670. F. Kisa, K. Yamada, M. Kaneko, M. Inagaki and R. Higuchi, Chem. Pharm. Bull., 2005, 53, 382.
671. T. Maruta, T. Saito, M. Inagaki, O. Shibata and R. Higuchi, Chem. Pharm. Bull., 2005, 53, 1255.
672. K. Yamada, R. Matsubara, M. Kaneko, T. Miyamoto and R. Higuchi, Chem. Pharm. Bull., 2001, 49, 447.
673. K. Yamada, N. Wada, H. Onaka, R. Matsubara, R. Isobe, M. Inagaki and R. Higuchi, Chem. Pharm. Bull., 2005, 53, 788.
674. K. Yamada, H. Onaka, M. Tanaka, M. Inagaki and R. Higuchi, Chem. Pharm. Bull., 2005, 53, 1333.
675. M. Inagaki, T. Miyamoto, R. Isobe and R. Higuchi, Chem. Pharm. Bull., 2005, 53, 1551.
676. L.-X. Zhang, X. Fan and J.-G. Shi, J. Asian Nat. Prod. Res., 2005, 7, 25.
677. A. A. Kicha, A. I. Kalinovsky, N. V. Ivanchina, Y. N. El'kin and V. A. Stonik, Russ. Chem. Bull., 1994, 43, 1726.
678. A. A. Kicha, N. V. Ivanchina, A. I. Kalinovsky, P. S. Dmitrenok and V. A. Stonik, Russ. Chem. Bull., 2005, 54, 1266.
679. E. V. Levina, A. I. Kalinovsky, P. V. Andriyashenko, P. S. Dmitrenok, D. L. Aminin and V. A. Stonik, J. Nat. Prod., 2005, 68, 1541.
680. H. D. Chludil and M. S. Maier, J. Nat. Prod., 2005, 68, 1279.
681. E. V. Levina, A. I. Kalinovsky, V. A. Stonik, P. S. Dmitrenok and P. V. Andriyashchenko, Russ. J. Bioorg. Chem., 2005, 31, 467.
682. W. Wang, H. Jang, J. Hong, C.-O. Lee, S.-J. Bae, S. Shin and J. H. Jung, Arch. Pharm. Res., 2005, 28, 285.
683. H. F. Tang, Y. H. Yi, L. Li, P. Sun, D. Z. Zhou and B. S. Liu, Chin. Chem. Lett., 2005, 16, 619.
684. H.-F. Tang, Y.-H. Yi, L. Li, P. Sun, S.-Q. Zhang and Y.-P. Zhao, Planta Med., 2005, 71, 458.
685. H.-F. Tang, Y.-H. Yi, L. Li, P. Sun, S.-Q. Zhang and Y.-P. Zhao, J. Nat. Prod., 2005, 68, 337.
686. J. Wu, Y. Yi, H. Wu, Q. He, Z. Zou and S. Zhang, Zhongguo Tianran Yaowu, 2005, 3, 276.
687. A. S. Silchenko, V. A. Stonik, S. A. Avilov, V. I. Kalinin, A. I. Kalinovsky, A. M. Zaharenko, A. V. Smirnov, E. Mollo and G. Cimino, J. Nat. Prod., 2005, 68, 564.
688. Z. Zou, Y. Yi, H. Wu, X. Yao, L. Du, W. Jiuhong, C.-C. Liaw and K.-H. Lee, J. Nat. Prod., 2005, 68, 540.
689. Z.-R. Zou, Y.-H. Yi, H.-M. Wu, J.-H. Wu, C.-C. Liaw and K.-H. Lee, J. Nat. Prod., 2003, 66, 1055.
690. Y. Tong, X. Zhang, F. Tian, Y. Yi, Q. Xu, L. Li, L. Tong, L. Lin and J. Ding, Int. J. Cancer, 2005, 114, 843.
691. G. Moraes, P. T. Northcote, A. S. Silchenko, A. S. Antonov, A. I. Kalinovsky, P. S. Dmitrenok, S. A. Avilov, V. I. Kalinin and V. A. Stonik, J. Nat. Prod., 2005, 68, 842.
692. A. M. de Moncerrat Iñiguez-Martinez, G. Guerra-Rivas, T. Rios and L. Quijano, J. Nat. Prod., 2005, 68, 1669.
693. E. J. Kim, C.-H. Kim, H.-J. Go, I. H. Kim, S. H. An, H.-Y. Sohn, H. Y. Park, H. D. Yoon, Y.-C. Chang, Y.-K. Hong and N. G. Park, J. Korean Fish. Soc., 2005, 38, 148.
694. E. L. Teuten, L. Xu and C. M. Reddy, Science, 2005, 307, 917.
695. G. Marsh, M. Athanasiadou, I. Athanassiadis, A. Bergman, T. Endo and K. Haraguchi, Environ. Sci. Technol., 2005, 39, 8684.
696. N. Sugiyama, M. Araki, M. Ishida, Y. Nagashima and K. Shiomi, Toxicon, 2005, 45, 595.
697. W. E. Houssen and M. Jaspars, J. Nat. Prod., 2005, 68, 453.
698. B. Chen, X. R. Shen and J. L. Kong, Chin. J. Chem., 2005, 23, 599.
699. I. Kontiza, C. Vagias, J. Jakupovic, D. Moreau, C. Roussakis and V. Roussis, Tetrahedron Lett., 2005, 46, 2845.
700. L. Han, X. Huang, I. Sattler, U. Moellmann, H. Fu, W. Lin and S. Grabley, Planta Med., 2005, 71, 160.
701. L. Han, X. Huang, I. Sattler, H.-M. Dahse, H. Fu, S. Grabley and W. Lin, Pharmazie, 2005, 60, 705.
702. S. Bao, Z. Deng, H. Fu, P. Proksch and W. Lin, Helv. Chim. Acta, 2005, 88, 2757.
703. L. Han, X. Huang, I. Sattler, H.-M. Dahse, H. Fu, W. Lin and S. Grabley, J. Nat. Prod., 2004, 67, 1620.
704. J. W. Blunt, B. R. Copp, M. H. G. Munro, P. T. Northcote and M. R. Prinsep, Nat. Prod. Rep., 2003, 20, 1.

---