Cyclic pentapeptides with anti-inflammatory, cytotoxic or α-glucosidase inhibitory activities from Basidiobolus meristosporus

Basidiobolus meristosporus is an opportunistic pathogen of mammals with unique habitats, but its metabolites have not been extensively studied. Through semi-preparative HPLC, nine undescribed cyclic pentapeptides were isolated from mycelia of B. meristosporus RCEF4516. The structure of the compounds 1-9 were identified with MS/MS and NMR data and designated as basidiosin D-L respectively. The absolute configurations were determined according to the advanced Marfey's method after compound hydrolysis. Bioactivity testing showed that compounds 1, 2, 3, 4 and 8 decreased NO production in LPS-activated RAW264.7 cells in a concentration-dependent manner. The nine compounds showed cytotoxicity against RAW264.7, 293 T and HepG2 cells. All the compounds except compound 7 showed stronger inhibitory effects on α-glucosidase than acarbose.