12,13-Dihydroxyfumitremorgin C, Fumitremorgin C, and Brevianamide F, Antibacterial Diketopiperazine Alkaloids from the Marine-Derived Fungus Pseudallescheria sp.

Dioxopiperazine alkaloids, 12R,13S-dihydroxyfumitremorgin C (1), fumitremorgin C (2), and brevianamide F (3), were isolated from the marine-derived fungus Pseudallescheria, and the absolute stereostructures of compounds 1-3 were elucidated on the basis of chemical and physicochemical evidence. Compounds 1-3 showed an antibacterial activity against. Staphylococcus aureus, methicillin-resistant S. aureus, and multidrug-resistant S. aureus. The MIC (minimum inhibitory concentration) values of compounds 1-3 were 125 μg/mL for all strains.