Citrinin Derivatives from Marine-derived Fungus Penicillim Grisefulvum and Antibacterial Activity

The marine fungus Penicillim grisefulvum was cultivated with 43 d at 28 degrees C, bioassay-guide fractionation of the marine fungus Penicillim grisefulvum led to the isolation of three citrinin derivatives (1-3), which were separated by silica gel column chromatography, C-18 column chromatography, Sephadex LH-20, and semi-preparative HPLC. Based on the HR-ESI-MS, 1D and 2D NMR, compounds 1-3 were assigned as 7-methyl-penicitrinone A (1), citrinin (2) and penicitrinone A (3), respectively. The absolute configuration of compound 1 was determined by comparision of experimental and calculated electronic cicular dichroism (ECD) data. Compound 1 displayed strong antibacterial activity against Vibrio parahemolyticus (MIC = 0.8 mu mol/L), which was stronger than the positive control of ciprofloxacin (MIC = 1.3 mu mol/L).