Secondary Metabolites from an Algicolous Aspergillus versicolor Strain

Two new compounds, asperversin A (1) and 9 xi-O-2(2,3-dimethylbut-3-enyl)brevianamide Q (2), and nine known compounds, brevianamide K (3), brevianamide M (4), aversin (5), 6,8-di-O-methylnidurufin (6), 6,8-di-O-methylaverufin (7), 6-O-methylaverufin (8), 5 alpha,8 alpha-epidioxyergosta-6,22-dien-3 beta-ol (9), ergosta-7,22-diene-3 beta,5 alpha,6 beta-triol (10), and 6 beta-methoxyergosta-7,22-diene-3 beta,5 alpha-diol (11), were obtained from the culture of Aspergillus versicolor, an endophytic fungus isolated from the marine brown alga Sargassum thunbergii. The structures of these compounds were established by spectroscopic techniques. Compounds 4, 7 and 8 exhibited antibacterial activities against Escherichia coli and Staphyloccocus aureus, and 7 also showed lethality against brine shrimp (Artemia salina) with an LC(50) value of 0.5 mu g/mL.