An antibacterial cytochalasin derivative from the marine-derived fungus Diaporthaceae sp. PSU-SP2/4

Abstract A new pentacyclic cytochalasin (diaporthalasin, 1 ) and a new ethyl trihydroxytridecatrienoate (diaporthacol, 2 ) together with five known compounds, R -mevalonolactone ( 4 ), dothiorelone C ( 5 ), (4 S ,7 S ,13 S )-4,7-dihydroxy-1,3-tetradeca-1,5-dienolide ( 6 ), 4β-acetoxy-9β,10β,15α-trihydroxyprobotrydial ( 7 ) and O -methyldihydrobotrydial ( 8 ) were isolated from the marine-derived fungus Diaporthaceae sp. PSU-SP2/4. The structures were established by spectroscopic techniques. Compound 1 displayed significant antibacterial activity against both Staphylococcus aureus and methicillin-resistant S. aureus with equal MIC values of 2 μg/mL.