α-Furanones, secondary metabolites from the fungus Cephalotrichum microsporum and their antibacterial activities

Abstract Cephalotrichum microsporum is a fungus isolated from the rhizosphere soil of Panax notoginseng . Four secondary metabolites (three new and one known α -furanones) of this fungus cultivated on a sterilized moistened-rice medium were isolated using an EtOAc extract. The structures of these compounds were determined by extensive spectroscopic data analysis using 1D- and 2D-NMR, ECD, and HRESIMS. In the antibacterial bioassay, compounds 2 and 3 displayed moderate inhibitory effects on S. aureus and B. subtilis with an inhibition rate of more than 50% at a concentration of 50.0 μg/mL. Additionally, compounds 1 ‒ 4 displayed weak antibacterial effects on MR Staphylococcus aureus.