A new 2-pyrrolidinone from Cladosporium sp. associated with Rubus tephrodes

The cultivation of Cladosporium sp., a fungus found in association with Rubus tephrodes Hance, resulted in the identification of sixteen compounds. New compound cladosporlactam (1) was distinguished by featuring a skeleton linked to a furan unit, with 3,4-dihydroxypyrrolidine-2-ketone as its characteristic structure. The structure of cladosporlactam was elucidated through meticulous analyses using NMR, electronic circular dichroism (ECD) calculations. Compound 1 could cause a gradual reduction in lipid droplets in a dose-dependent manner without inducing cytotoxicity and demonstrated intermediate antimicrobial activity against Staphylococcus aureus with MIC values of 8 mu g/mL.