New Antibacterial Dihydropyrones Induced by Co-Culture of Penicillium crustosum PRB-2 and Penicillium citrinum HDN11-186

Two new dihydropyrones, rhytismatones C ( 1 ) and D ( 2 ), and a known compound, penicillenol A 1 ( 3 ), were isolated from the co-culture broth of the deep-sea-derived fungus Penicillium crustosum PRB-2 and Suaeda salsa-derived endophytic fungus Penicillium citrinum HDN11-186. Their structures were elucidated through comprehensive analysis of nuclear magnetic resonance (NMR) spectra and mass spectra. The absolute configurations of new compounds were determined by calculating the electronic circular dichroism (ECD) spectrum. UPLC-MS data showed that compounds 1 – 3 could only be detected in the media of co-culture, suggesting new biosynthetic pathways were activated in the co-cultured fungi. Compound 1 showed obvious antibacterial activities against Proteus sp. MMBC-1002 and Bacillus subtilis MMBC-1004 with minimum inhibitory concentration (MIC) both at 25 µmol L −1 .