[Antibacterial new diketopiperazines and azaphilones from endophytic fungus Penicillium polonicum derived from Emmenopterys henryi].

Abstract

Six secondary metabolites were isolated from the rice fermentation products of the endophytic fungus Penicillium polonicum from Emmenopterys henryi by silica gel column chromatography, gel column chromatography, and semi-preparative high-performance liquid chromatography(HPLC). Their structures were elucidated by NMR, mass spectrometry, and other spectroscopic methods in combination with literature data. The compounds were identified as penicilazine A(1), penicilazine B(2), penicilazone C(3), chermesinone B(4), chaetoglobosin G(5), and communesin D(6). Compounds 1 and 2 are diketopiperazine alkaloids. Among them, compound 1 was obtained from nature for the first time, and compound 2 was identified as a new compound. Compound 3 was identified as a new azaphilone-type compound. Antibacterial activity assays showed that compound 1 exhibited moderate antibacterial activity against Vibrio alginolyticus, Staphylococcus aureus, and Erwinia carotovora with MIC values of 12.5, 12.5, and 25 μg·mL~(-1), respectively. Compound 2 displayed antibacterial activity against V. anguillarum and V. alginolyticus, with MIC values of 25 μg·mL~(-1) for both strains.