Ergostane steroids from <i>Aspergillus</i> sp. M904 in Vietnam

Seven ergostane steroids were isolated from the cultures of Aspergillus sp. M904, an endophytic fungus isolated from the marine sediment sample collected at a depth of ten meters in Binh Dinh, Vietnam. These compounds include 5α,6α-epoxy-(22E,24R)-ergosta-8(14),22-diene-3β,7α-diol (1), 5α,6α-epoxy-(22E,24R)-ergosta-8(9),22-diene-3β,7α-diol (2), ergosterol (3), ergosterol peroxide (4), 3β,5α,6α-trihydroxy-ergosta-7,22-diene (5), 3β,5α,9α-trihydroxy-ergosta-7,22-diene-6-one (6), 3β-hydroxy-5α,9α-epoxy-ergosta-7,22-dien-6-one (7). Their structures were identified through MS and NMR data analyses. All compounds were evaluated for their antimicrobial activity against a panel of clinically significant microorganisms. Compounds 1–7 had inhibitory activity against from one to six tested strains with MIC values from 64–256 µg/mL.