Three new compounds, sydowianumols A (1), B (2), and C (3), were isolated from culture broth and mycelial extracts of Poculum pseudosydowianum (TNS-F-57853), an endophytic fungus isolated from fresh leaves of Quercus crispula. The structures of new compounds 1-3 were elucidated from spectroscopic data. Sydowianumols A (1) and B (2) exhibited antimicrobial activity against methicillin-resistant Staphylococcus aureus (MRSA) with 90% minimum inhibitory concentration (MIC90) values of 12.5 µg/mL.
Keywords: Poculum pseudosydowianum; Quercus crispula; antimicrobial activity; endophytic fungus; methicillin-resistant Staphylococcus aureus (MRSA); sydowianumol.