Penicilazaphilones D and E: two new azaphilones from a sponge-derived strain of the fungus Penicillium sclerotiorum

Abstract

Two new azaphilones, penicilazaphilones D (1) and E (2), along with four known analogs (3–6), were obtained from the sponge-derived fungus Penicillium sclerotiorum. Their structures were elucidated on the basis of comprehensive spectroscopic analyses, ECD calculation, single-crystal X-ray diffraction and comparison to the biosynthetically related compound 5. Compound 1 represents the second reported azaphilone with a C-4 aliphatic side chain, and 2 is the first azaphilone with a tetrahydrofuran ring at C-3. Compound 3 displayed strong antiviral activity against HSV (IC₅₀ = 19.5 μM) and EV71 (IC₅₀ = 132 μM), 16 and 3 fold more potent than the positive control ribavirin, respectively.