Yu Chen‡
a,
Ziyu Ma‡a,
Haida Tenga,
Fei Gana,
Hui Xiongb,
Zhinan Mei*b and
Guangzhong Yang*bc
aCollege of Chemistry and Material Sciences, South-Central University for Nationalities, Wuhan 430074, P. R. China
bSchool of Pharmaceutical Sciences, South-Central University for Nationalities, Wuhan 430074, P. R. China. E-mail: meizhinan@163.com; yanggz888@126.com; Fax: +86 27 6784 1196; Tel: +86 27 6784 1196
cNational Demonstration Center for Experimental Ethnopharmacology Education (South-Central University for Nationalities), Wuhan 430074, P. R. China
First published on 17th April 2019
Nine undescribed caged polycyclic polyprenylated acylphloroglucinols (PPAPs), including adamantane type PPAPs (1–2), and homoadamantane type PPAPs (3–9), were isolated from the fruits of Garcinia multiflora, along with three known analogues. A new epimeric pair of isohypersampsonone B (5) and epi-isohypersampsonone B (6), featuring an unusual hexahydrofuro[2,3-b]furan-diepoxy ring system fused in a homoadamantane skeleton, was not separated due to the rapid equilibration between the two isomeric forms. All new caged PPAPs (1–9), sharing a common isogeranyl group, were determined on the basis of comprehensive NMR and MS spectroscopic data. Their cytotoxicity against three human tumor cell lines (SGC-7901, HepG2, HCT-116) and the nitric oxide production inhibitory activity of lipopolysaccharides-stimulated RAW 264.7 cells were tested. Compounds 8 and 12 displayed mild cytotoxicity against three human cancer cell lines with IC50 values of 10–20 μM. Furthermore, compounds 8 and 12 also exhibited NO production inhibitory effect with an IC50 value of 18.24 and 12.50 μM respectively.
Taken together, these results prompted us to investigate the isolation of further caged PPAPs form G. multiflora and evaluate their biological activities. As a result, nine undescribed caged polycyclic polyprenylated acylphloroglucinols (PPAPs), including adamantane type PPAPs (1–2) and homoadamantane type PPAPs (3–9) were isolated from the fruits of G. multiflora, along with three known analogues. Herein, we report the isolation, structural elucidation, and biological activities of these isolated compounds.
Compound 2 was obtained as an amorphous powder. It gave a molecular formula of C38H48O5 according to its HR-ESI-MS at m/z 585.35748 [M + H]+ (calcd. 585.35745). Detailed analysis of the 1D and 2D NMR spectra indicated that compound 2 featured a unique caged tetracyclo-[6.3.1.13,10.03,7]tridecane skeleton which was the same as those of hyperisampsins A–D.10 Comparison of the 13C NMR data of 2 with that of hyperisampsin C revealed that two compounds were similar except for the presence of an isogeranyl group at C-5 in 2 instead of a geranyl group in hyperisampsin C. The constitution of 2 was confirmed by HMBC correlations between H2-22 and C-5 (δC 68.2) and C-9 (δC 201.9). The relative configuration of 2 was established as the same that of hyperisampsin C by ROESY spectrum. Thus, compound 2 was established and named isohyperisampsin C.
Compound 3 was isolated as colorless amorphous powder. Its molecular formula was determined by its 13C NMR and HR-ESI-MS data (m/z 587.37323 [M + H]+, calcd. 587.3731) as C38H50O5. The 13C and DEPT NMR data showed the characteristic resonances of homo-adamantane type PPAPs, including three nonconjugated carbonyl groups at δC 206.6 (C-2), 206.4 (C-4) and 204.5 (C-9), four quaternary carbons at δC 82.4 (C-1), 72.1 (C-3), 66.9 (C-5), and 52.0 (C-8), two methine groups at δC 43.6 (C-7) and 57.9 (C-33), and two methylene groups at δC 48.0 (C-6) and 28.2 (C-32). Comparison of its 1H and 13C NMR data with those of hypersampsonone G,11 a known homo-adamantane type PPAP from H. sampsonii, suggested that they had a same tetrocyclo[7.3.1.13,11.03,7]tetradecane core skeleton. However, the only structural difference was an isogeranyl group at C-5 in 3 instead of a geranyl group in hypersampsonone G. This was further supported by HMBC correlations between H2-22 and C-5 (δC 66.9), C-4 (δC 206.4) and C-9 (δC 204.5). In the ROESY spectrum of 3, NOE correlations of H-7/H3-37, H-33/H3-37, H-33/H3-35 and H-18/H3-35 indicated that these protons were cofacial and designated as α-oriented. Therefore, compound 3 was established and named isohypersampsonone G.
Compound 4 was isolated as amorphous powder. It had the molecular formula C35H44O5 as determined by HR-ESI-MS at (m/z 545.32617 [M + H]+, calcd. 545.32615), with three carbon atoms less than that of 3. In comparison of 13C NMR data of 4 with those of 3, signals of C-17, C-18, and C-34 in 4 appeared at high chemical shift, suggesting that 1-hydroxy-1-methylethyl group at C-18 in 3 was replaced by a hydroxy group in 4. This was further supported by HMBC correlations between H3-35 and H3-36 and C-34 (δC 49.8), C-33 (δC 53.2) and C-18 (δC 82.0). In the ROESY spectrum of 4, NOE correlations between H-33/H3-37, H-33/H3-35 and H-18/H3-36 suggested that H-33 and 18-OH were α-oriented respectively. Thus, compound 4 was assigned as depicted in Fig. 1 and was named garcimultinone A.
Compounds (5) and (6) were isolated as inseparable epimeric mixture and obtained as white amorphous powders. The ratio of 5 and 6 is about 5:
1 by NMR analysis. Their molecular formula was determined as C35H44O6 by HR-ESI-MS data (m/z 561.32141 [M + H]+, calcd. 561.32107), Firstly, we discussed the structure elucidation of 5. Detailed analysis of the 1D and 2D NMR spectra indicated that compound 5 had an unusual hexahydrofuro[2,3-b]furan-diepoxy ring system fused in homoadamantane skeleton. Comparison of 1H and 13C NMR data of 5 with those of hypersampsonone B11 indicated that the two compounds were closely related, except for an isogeranyl group at C-5 of 5 instead of a geranyl group of hypersampsonone B. The relative configuration of 5 was determined by analyzing its ROESY data. H-33 and 18-OH were determined as α and β-oriented based on the NOE correlations between H-33/H3-35 and H-18/H3-35. Except for the 13C-NMR signals of 5 mentioned above, the remaining 35 carbon signals were attributed to 6. In comparison of 1H and 13C NMR data of 6 with those of 5, it was found that NMR data of 6 were almost identical with those of 5, except for the chemical shift of C-18 (δC 98.7 in 5 and δC 100.0 in 6) and coupling constants between and CH2-17 and H-18 [δH 5.84 (t, J = 6.6 Hz) in 5 and 5.79 (dd, J = 6.6, 3.6 Hz) in 6], indicating that 6 was a 18-epimer of 5. Thus, compound 5 and 6 were assigned as depicted in Fig. 1 and were named isohypersampsonone B and epi-isohypersampsonone B, respectively. We tried to isolate the epimeric mixture by HPLC. However, it was unsuccessful for the isolation of isohypersampsonone B and epi-isohypersampsonone B due to the rapid equilibration between the two isomeric forms.
Compound 7 was obtained white amorphous powder. It gave the molecular formula of C38H50O7 on the basis of HR-ESI-MS data (m/z 619.36310 [M + H]+, calcd. 619.36293). Furthermore, the NMR data of 7 were similar to those of hypersampsonone C,11 indicating that 7 is also a homoadamantane derivative with an unique tetrahydrofuro[3,4-b]furan moiety. Extensive comparison of NMR data of 7 with those of hypersampsonone C revealed that the geranyl attached to C-5 in hypersampsonone C was replaced by an isogeranyl in 7. The constitution structure of 7 was also confirmed by 2D-NMR spectroscopy. The relative configuration of 7 was assigned to be the same as that of hypersampsonone C by comparison of its 1D NMR and ROESY data with those of hypersampsonone C. Thus, the structure of 7 was deduced completely as showed in Fig. 1 and was named isohypersampsonone C.
Compound 8 was isolated as amorphous powder. Its molecular formula was determined by its 13C NMR and HR-ESI-MS data (m/z 635.35791 [M + H]+, calcd. 635.35784) as C38H50O8, with one more O-atom than that of garcimultiflorone G.8 Furthermore, these NMR data showed high degrees of similarity to those of hyperisampsin O,12 which suggested that 8 is also a homoadamantane PPAP with an 1,2-dioxepane functionality. In comparison with those of hyperisampsin O indicated that 8 possessed an isogeranyl at C-5 instead of a geranyl at C-5 in hyperisampsin O. In the ROESY spectrum of 8, NOE correlations between H-33/H3-35, H-18/H-33 and H3-37/H-33 implied that both H-18 and H-33 were α-oriented. Therefore, compound 8 was assigned as depicted in Fig. 1 and was named isohyperisampsin O.
Compound 9 was isolated as amorphous powder. It had the molecular formula C35H44O7 as determined by HR-ESI-MS at (m/z 577.31610 [M + H]+, calcd. 577.31598), with three carbon atoms less than that of 8. In comparison with 8, signals of C-17 and C-18 in 9 appeared at high chemical shift, suggesting that 1-hydroperoxy-1-methylethyl group at C-18 in 8 was replaced by a hydroxy group in 9. This was further supported by HMBC correlations from H2-17 to C-3 (δC 66.6), C-18 (δC 99.8), C-2 (δC 208.4) and C-4 (δC 205.4). 18-OH configuration was established as β-oriented based on the NOE correlations between H-18/H-33, H-33/H3-35 in the ROESY spectrum of 9. Thus, compound 9 was assigned as depicted and was named garcimultinone B (Fig. 2–4).
The absolute stereochemistry of 1–9 were assigned by CD analysis. Nine new isolates were elucidated to possess adamantyl and homoadamantyl skeleton with an isogeranyl group. Considering the isogeranyl group away from the chromophoric system, the absolute configuration of C-23 has an insignificant effect on the CD spectrum.13 Thus, the absolute configurations of compounds 1–9 except C-23 can be determined by comparison of their CD curves with those of known compounds. Compounds 1 (adamantane type) and 3–9 (homoadamantyl type) displayed the negative Cotton effect around 330 nm, indicating 1R configuration based on the CD benchmark summarized by Zhang et al.10 Furthermore, the ECD spectra of 1, 3 and 5–8 matched well those of known compounds hyperisampsin G,10 hypersampsonone G,11 hypersampsonone B,11 hypersampsonone C11 and hyperisampsins O12 respectively, in which the main differences in their structure are that the former have an isogeranyl group attached to C-5 position, while the latter have a geranyl group. Hence, the absolute configuration of 1 and 3–9 was assigned as depicted in Fig. 1. The absolute configuration of C-1 for most of naturally occurring adamantyl and homoadamantyl PPAPs appeared as 1R, which showed the negative CE at 333 nm.10 However, a positive Cotton effect at 325 nm and a negative Cotton effect at 243 and 294 nm were observed in ECD spectrum of 2, which was the opposite to those of hyperisampsin C.10 Consequently, the absolute configuration of 2 was established as depicted in Fig. 1.
The known compounds garcimultiflorone D (10),6 sampsonione B (11)14 and hyphenrone M (12)15 were identified by comparison of their NMR data with those in the literature.
All the isolated compounds were assessed for their cytotoxic effects against three human tumor cell lines (SGC-7901, HepG2, HCT-116) by CCK-8 method. In comparison with the positive control cisplatin against SGC-7901, HepG2 and HCT-116 with IC50 values 7.35, 4.58 and 8.23 μM respectively, compounds 8 showed mild cytotoxicity against SGC-7901 and HepG2 with an IC50 values of 13.05 and 18.05 μM, and compounds 12 also displayed mild cytotoxicity against three tested human cancer cells with an IC50 values of 17.63, 19.64, and 18.93 μM respectively. The other compounds showed no obvious cytotoxicity against three tested human cancer cells (IC50 > 20 μM). Additionally, the NO production inhibitory activity of all isolated compounds on LPS-activated RAW 264.7 cells was also tested. The cell viability was first confirmed by the CCK-8 method to determine whether the cytotoxicity of the tested compounds resulted in the inhibition of NO production. Compounds 8 and 12 also exhibited NO production inhibitory effect with IC50 values 18.24 and 12.50 μM respectively, while did not obviously affect cell viability up to 20 μM and the others compounds had no inhibitory activity (IC50 > 20 μM).
Epi-isosampsonione J (1), white amorphous powder. [α]D = +55.0° (c = 0.02, MeOH); UV (MeOH) λmax nm (logε): 215 (sh) (3.88), 245 (4.02); ECD (c 3.42 × 10−4 M, MeOH) λ (Δε): 213 (+1.80), 241 (−4.55), 262 (+1.94), 293 (+0.82), 335 (−0.77); 1H- and 13C-NMR see Tables 1 and 3; HR-ESI-MS m/z: 583.34296 [M − H]− (calcd for C38H47O5−: 583.3429).
No. | 1a | 2b | 3b | 4b |
---|---|---|---|---|
a Recorded in CD3OD.b Recorded in CDCl3. | ||||
6 | 2.69–2.78 m; 2.41–2.48 m | 2.74 d (14.4); 2.40–2.47 m | 2.55 dd (13.2, 6.0); 1.75–1.82 m | 2.56 dd (13.8, 5.4); 1.76–1.82 m |
7 | 1.82–1.88 m | 1.88–1.94 m | 2.13 t (6.6) | 2.13–2.19 m |
12/16 | 7.23 d (7.2) | 7.22 d (7.2) | 7.31 m | 7.34 d (7.2) |
13/15 | 7.32 t (7.2) | 7.37 t (7.2) | 7.31m | 7.31 t (7.2) |
14 | 7.49 t (7.2) | 7.44 t (7.2) | 7.43 m | 7.45 t (7.2) |
17 | 2.80 dd (15.0, 7.2); 2.31 dd (15.0, 7.2) | 2.15 dd (14.4, 6.6); 2.38–2.45 m | 2.84 dd (13.2, 12.0); 2.47 dd (13.2, 9.0) | 3.16 dd (15.0, 4.8); 2.13–2.20 m |
18 | 4.98 t (7.2) | 2.99–3.06 m | 1.96 dd (12.0, 9.0) | 4.00 t (6.6) |
20 | 1.69 s | 1.20 s | 1.33 s | |
21 | 1.63 s | 1.36 s | 1.41 s | |
22 | 2.03–2.14 m; 1.80–1.88 m | 2.05–2.13 m; 1.87 dd (15.0, 3.0) | 2.23 dd (14.4, 10.2); 1.75–1.82 m | 2.88 dd (14.4, 10.2); 1.78–1.84 m |
23 | 2.68–2.79 m | 2.45–2.53 m | 2.56–2.64 m | 2.60–2.67 m |
25 | 1.57 s | 1.69 s | 1.45 s | 1.42 s |
26 | 4.64 s; 4.59 s | 4.72 s; 4.68 s | 4.53 br s; 4.66 br s | 4.67 br s; 4.47 br s |
27 | 2.03–2.13 m | 2.05–2.17 m | 1.97–2.04 m | 1.94–2.03 m |
28 | 5.03 t (7.2) | 5.02 t (6.6) | 5.00 t (7.2) | 4.99 t (6.6) |
30 | 1.63 s | 1.60 s | 1.60 s | 1.60 s |
31 | 1.67 s | 1.66 s | 1.68 s | 1.69 s |
32 | 2.42–2.48 m | 3.02–3.09 m | 2.19 dd (13.8, 7.2); 1.43–1.52 m | 2.17–2.24 m; 1.44–1.51 m |
33 | 2.74–2.80 m | 2.40–2.48 m | 2.06 dd (12.0, 7.8) | 2.38 dd (13.2, 7.8) |
35 | 1.30 s | 1.23 s | 1.11 s | 1.02 s |
36 | 1.32 s | 1.30 s | 1.07 s | 0.99 s |
37 | 1.36 s | 1.52 s | 1.54 s | 1.59 s |
38 | 1.44 s | 1.53 s | 1.41 s | 1.43 s |
No. | 5 | 6 | 7 | 8 | 9 |
---|---|---|---|---|---|
6 | 2.61 dd (15.0, 6.6); 2.19 d (16.2) | 2.61 dd (15.0, 6.6); 2.19 d (16.2) | 2.29–2.39 m | 2.68 dd (14.4, 6.6); 1.80 d (13.8) | 2.57–2.64 m; 1.77–1.84 m |
7 | 1.73–1.81 m | 1.73–1.81 m | 1.96–2.03 m | 2.05–2.13 m | 2.05–2.10 m |
12/16 | 7.56 d (7.2) | 7.56 d (7.2) | 7.58 d (8.4) | 7.31 m | 7.33 m |
13/15 | 7.38 t (7.8) | 7.38 t (7.8) | 7.26 t (7.8) | 7.31 m | 7.33 m |
14 | 7.43 t (7.8) | 7.43 t (7.8) | 7.39 t (7.8) | 7.43 m | 7.46 m |
17 | 2.99 dd (16.2, 6.6); 2.39–2.47 m | 2.89–2.96 m; 2.39–2.47 m | 5.07 d (2.4) | 3.44 dd (14.0, 11.4); 1.64 dd (15.0, 3.0) | 3.30 dd (15.0, 9.0); 1.74–1.82 m |
18 | 5.84 t (6.6) | 5.79 dd (6.6, 3.6) | 3.92 d (2.4) | 4.94 dd (11.4, 3.0) | 5.86–5.92 m |
20 | 1.26 s | 1.19 s | |||
21 | 1.33 s | 1.20 s | |||
22 | 2.20–2.29 m; 2.04–2.14 m | 2.20–2.29 m; 2.04–2.14 m | 2.14–2.22 m; 2.04–2.11 m | 2.28 dd (14.4, 9.6); 1.85 dd (14.4, 4.2) | 2.28 dd (14.4, 9.6); 1.77–1.84 m |
23 | 2.36–2.44 m | 2.36–2.44 m | 2.50–2.57 m | 2.57–2.65 m | 2.58–2.66 m |
25 | 1.69 s | 1.70 s | 1.72 s | 1.56 s | 1.50 s |
26 | 4.73 s | 4.73 s | 4.79 s; 4.81 s | 4.70 s; 4.62 s | 4.57 br s; 4.70 br s |
27 | 2.00–2.07 m; 1.87–1.95 m | 2.00–2.07 m; 1.87–1.95 m | 2.10–2.16 m; 2.01–2.07 m | 2.04–2.14 m | 2.01–2.07 m |
28 | 5.07 t (6.6) | 5.07 t (6.6) | 5.03–5.09 m | 5.03 t (6.6) | 5.00 t (6.6) |
30 | 1.55 s | 1.56 s | 1.59 s | 1.62 s | 1.61 s |
31 | 1.64 s | 1.64 s | 1.65 s | 1.69 s | 1.68 s |
32 | 1.87–2.02 m | 1.87–2.02 m | 2.04–2.10 m; 1.97–2.04 m | 2.31–2.40 m; 1.45–1.55 m | 2.33 dd (13.8, 7.2); 1.45–1.52 m |
33 | 2.41–2.48 m | 2.50–2.55 m | 2.46–2.53 m | 2.72 t (10.2) | 2.58–2.66 m |
35 | 1.58 s | 1.70 s | 1.37 s | 1.33 s | 1.32 s |
36 | 1.46 s | 1.50 s | 1.34 s | 1.20 s | 1.25 s |
37 | 1.21 s | 1.19 s | 1.44 s | 1.35 s | 1.39 s |
38 | 1.47 s | 1.47 s | 1.39 s | 1.48 s | 1.44 s |
OH | 4.75 s |
No. | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |
---|---|---|---|---|---|---|---|---|---|
1 | 83.7 C | 82.7 C | 82.4 C | 82.1 C | 81.5 C | 82.0 C | 82.6 C | 82.3 C | 82.2 C |
2 | 203.0 C | 198.8 C | 206.6 C | 205.3 C | 207.5 C | 207.7 C | 203.5 C | 209.0 C | 208.4 C |
3 | 74.3 C | 78.3 C | 72.1 C | 74.7 C | 67.6 C | 70.4 C | 76.3 C | 65.9 C | 66.6 C |
4 | 204.4 C | 202.6 C | 206.4 C | 208.3 C | 115.6 C | 118.1 C | 106.5 C | 205.9 C | 205.4 C |
5 | 69.7 C | 68.2 C | 66.9 C | 66.3 C | 57.5 C | 57.8 C | 57.5 C | 67.5 C | 67.1 C |
6 | 44.9 CH2 | 38.6 CH2 | 48.0 CH2 | 48.8 CH2 | 30.8 CH2 | 30.7 CH2 | 40.6 CH2 | 45.2 CH2 | 47.0 CH2 |
7 | 47.1 CH | 44.4 CH | 43.6 CH | 43.6 CH | 43.8 CH | 43.7 CH | 44.6 CH | 44.8 CH | 44.5 CH |
8 | 56.7 C | 57.8 C | 52.0 C | 52.6 C | 48.0 C | 48.2 C | 52.0 C | 50.9 C | 51.3 C |
9 | 203.7 C | 201.9 C | 204.5 C | 204.0 C | 208.6 C | 208.9 C | 208.0 C | 204.1 C | 203.9 C |
10 | 194.6 C | 193.4 C | 194.0 C | 193.5 C | 194.7 C | 194.6 C | 194.7 C | 192.6 C | 192.6 C |
11 | 136.4 C | 135.3 C | 136.3 C | 136.1 C | 135.9 C | 136.9 C | 137.1 C | 135.3 C | 135.2 C |
12 | 130.7 CH | 129.2 CH | 129.3 CH | 129.4 CH | 129.5 CH | 128.6 CH | 129.7 CH | 129.1 CH | 129.2 CH |
13 | 129.1 CH | 128.2 CH | 128.0 CH | 128.0 CH | 128.6 CH | 128.2 CH | 127.9 CH | 128.1 CH | 128.3 CH |
14 | 133.7 CH | 132.6 CH | 132.0 CH | 132.2 CH | 132.4 CH | 132.3 CH | 132.0 CH | 132.5 CH | 132.5 CH |
15 | 129.1 CH | 128.2 CH | 128.0 CH | 128.0 CH | 128.6 CH | 128.2 CH | 127.9 CH | 128.1 CH | 128.3 CH |
16 | 130.7 CH | 129.2 CH | 129.3 CH | 129.4 CH | 129.5 CH | 128.6 CH | 129.7 CH | 129.1 CH | 129.2 CH |
17 | 28.1 CH2 | 23.8 CH2 | 32.2 CH2 | 38.7 CH2 | 46.0 CH2 | 45.6 CH2 | 83.3 CH | 31.5 CH | 37.8 CH |
18 | 120.7 CH | 52.3 CH | 60.1 CH | 82.0 CH | 98.7 CH | 100.0 CH | 88.7 CH | 85.9 CH | 99.8 CH |
19 | 135.6 C | 81.9 C | 73.2 C | 70.0 C | 84.3 C | ||||
20 | 18.5 CH3 | 29.1 CH3 | 31.3 CH3 | 27.4 CH3 | 21.8 CH3 | ||||
21 | 26.1 CH3 | 33.1 CH3 | 30.5 CH3 | 26.4 CH3 | 21.4 CH3 | ||||
22 | 34.0 CH2 | 31.5 CH2 | 35.8 CH2 | 35.9 CH2 | 34.7 CH2 | 34.8 CH2 | 35.1 CH2 | 34.8 CH2 | 35.2 CH2 |
23 | 44.7 CH | 43.4 CH | 43.3 CH | 43.3 CH | 43.4 CH | 43.4 CH | 43.2 CH | 43.6 CH | 43.6 CH |
24 | 150.2 C | 149.1 C | 149.1 C | 149.2 C | 149.4 C | 149.5 C | 150.4 C | 149.0 C | 148.8 C |
25 | 18.6 CH3 | 18.5 CH3 | 18.0 CH3 | 17.9 CH3 | 19.7 CH3 | 19.8 CH3 | 19.3 CH3 | 18.2 CH3 | 18.0 CH3 |
26 | 113.5 CH2 | 112.3 CH2 | 112.8 CH2 | 112.9 CH2 | 111.6 CH2 | 111.5 CH2 | 112.2 CH2 | 112.7 CH2 | 113.1 CH2 |
27 | 34.7 CH2 | 34.0 CH2 | 33.1 CH2 | 32.9 CH2 | 30.9 CH2 | 30.9 CH2 | 31.9 CH2 | 33.6 CH2 | 33.4 CH2 |
28 | 124.3 CH | 122.6 CH | 122.9 CH | 122.7 CH | 122.8 CH | 122.8 CH | 123.2 CH | 122.7 CH | 122.7 CH |
29 | 133.2 C | 132.5 C | 132.2 C | 132.4 C | 132.1 C | 132.1 C | 132.3 C | 132.4 C | 132.4 C |
30 | 18.3 CH3 | 18.2 CH3 | 18.2 CH3 | 18.2 CH3 | 18.2 CH3 | 18.2 CH3 | 18.2 CH3 | 18.2 CH3 | 18.2 CH3 |
31 | 26.6 CH3 | 25.9 CH3 | 26.0 CH3 | 26.0 CH3 | 25.9 CH3 | 25.9 CH3 | 25.9 CH3 | 26.0 CH3 | 26.0 CH3 |
32 | 57.9 CH | 59.0 CH | 28.2 CH2 | 28.4 CH2 | 25.3 CH2 | 25.3 CH2 | 29.1 CH2 | 31.7 CH2 | 32.0 CH2 |
33 | 62.8 CH | 56.3 CH | 57.9 CH | 53.2 CH | 49.6 CH | 48.9 CH | 50.1 CH | 42.3 CH | 41.8 CH |
34 | 58.9 C | 79.4 C | 47.2 C | 49.8 C | 86.5 C | 86.2 C | 86.4 C | 88.8 C | 88.0 C |
35 | 19.3 CH3 | 26.3 CH3 | 30.8 CH3 | 23.2 CH3 | 30.6 CH3 | 32.2 CH3 | 31.5 CH3 | 28.9 CH3 | 29.4 CH3 |
36 | 25.1 CH3 | 32.0 CH3 | 16.2 CH3 | 19.2 CH3 | 28.0 CH3 | 28.8 CH3 | 24.3 CH3 | 18.2 CH3 | 18.1 CH3 |
37 | 23.0 CH3 | 23.5 CH3 | 23.1 CH3 | 23.0 CH3 | 22.6 CH3 | 22.5 CH3 | 23.1 CH3 | 22.8 CH3 | 22.9 CH3 |
38 | 23.5 CH3 | 23.9 CH3 | 26.7 CH3 | 27.1 CH3 | 25.4 CH3 | 25.3 CH3 | 27.0 CH3 | 25.4 CH3 | 25.5 CH3 |
Isohyperisampsin C (2), white amorphous powder. [α]D = +93.3° (c = 0.02, MeOH); UV (MeOH) λmax nm (logε): 210 (3.87), 250 (3.87), 295 (3.42), 325 (3.41); ECD (c 3.42 × 10−4 M, MeOH) λ (Δε): 219 (−2.07), 243 (−5.36), 264 (−1.32), 294 (−5.29), 325 (+8.79); 1H- and 13C-NMR see Tables 1 and 3. HR-ESI-MS m/z: 585.35748 [M + H]+ (calcd for C38H49O5+: 585.35745).
Isohypersampsonone G (3), white, amorphous powder. [α]D = +34.2° (c = 0.01, MeOH); UV (MeOH) λmax nm (logε): 210 (4.14), 245 (4.12); ECD (c 1.71 × 10−4 M, MeOH) λ (Δε): 210 (−0.03), 244 (−6.56), 286 (+2.40), 321 (−0.55); 1H- and 13C-NMR see Tables 1 and 3; HR-ESI-MS m/z: 587.37323 [M + H]+ (calcd for C38H51O5+: 587.37310).
Garcimultinone A (4), white amorphous powder. [α]D = −25.6° (c = 0.02, MeOH); UV (MeOH) λmax nm (logε): 210 (3.80), 245 (3.79); ECD (c 3.68 × 10−4 M, MeOH) λ (Δε): 210 (+1.06), 244 (−5.00), 286 (+1.24), 307 (−0.71); 1H- and 13C-NMR see Tables 1 and 3; HR-ESI-MS m/z: 545.32617 [M + H]+ (calcd for C35H45O5+: 545.32615).
Isohypersampsonone B (5) and epi-isohypersampsonone B (6), white amorphous powders. [α]D = +60.0° (c = 0.01, MeOH); UV (MeOH) λmax nm (logε): 245 (4.32); ECD (c 1.79 × 10−4 M, MeOH) λ (Δε): 224 (+16.0), 246 (+21.46), 290 (−7.81); 1H- and 13C-NMR see Tables 2 and 3; HR-ESI-MS m/z: 561.32141 [M + H]+ (calcd for C35H45O6+: 561.32107).
Isohypersampsonone C (7), white amorphous powder. [α]D = +81.7° (c = 0.02, MeOH); UV (MeOH) λmax nm (logε): 215 (3.90), 245 (4.03); ECD (c 3.24 × 10−4 M, MeOH) λ (Δε): 209 (+22.01), 255 (−7.96), 289 (+3.90), 319 (−0.48); 1H- and 13C-NMR see Tables 2 and 3; HR-ESI-MS m/z: 619.36310 [M + H]+ (calcd for C38H51O7+: 619.36293).
Isohyperisampsin O (8), white amorphous powder. [α]D = +22.4° (c = 0.06, MeOH); UV (MeOH) λmax nm (logε): 240 (3.60); ECD (c 9.46 × 10−4 M, MeOH) λ (Δε): 221 (+4.99), 243 (−3.20), 261 (+1.24); 319 (−2.46); 1H- and 13C-NMR see Tables 2 and 3; HR-ESI-MS m/z: 635.35791 [M + H]+ (calcd for C38H51O8+: 635.35784).
Garcimultinone B (9), white amorphous powder. [α]D = +28.3° (c = 0.04, MeOH); UV (MeOH) λmax nm (logε): 210 (3.52), 245 (3.57); ECD (c 6.94 × 10−4 M, MeOH) λ (Δε): 222 (+2.34), 241 (−0.89), 255 (+1.63), 313 (−1.15); 1H- and 13C-NMR see Tables 2 and 3; HR-ESI-MS m/z: 577.31610 [M + H]+ (calcd for C35H45O7+: 577.31598).
Footnotes |
† Electronic supplementary information (ESI) available. See DOI: 10.1039/c9ra01279f |
‡ These authors contributed equally to this work. |
This journal is © The Royal Society of Chemistry 2019 |