Antibacterial oxygenated ergostane-type steroids produced by the marine sponge-derived fungus Aspergillus sp.

Two oxygenated ergostane-type steroids including one new compound, 3 β -hydroxy-5 α ,6 β -methoxyergosta-7,22-dien-15-one ( 1 ) along with a known analogue ergosta-6,22-dien-3 β ,5 α ,8 α -triol ( 2 ) were isolated from the crude extracts of the marine sponge-derived fungus Aspergillus sp. Their structures were elucidated on the basis of combined NMR and MS spectroscopic methods. Compound 1 was a marine ergostane-type steroid with two methoxy groups at C-5 and C-6, respectively. These oxygenated ergostane-type steroids were evaluated for their antibacterial activities against human or aquatic pathogens. Among them, compound 1 exhibited antibacterial activity against Staphylococcus aureus.