Three New Heptelidic Acid Derivatives from the Culture of Mushroom Lentinellus ursinus.

Three new heptelidic acid derivatives (1-3) including two new dimeric esters and two known heptelidic acid analogues (4 and 5) were isolated from the solid culture of mushroom Lentinellus ursinus. The structures of new compounds were confirmed by the analysis of NMR and HRESIMS spectroscopic data. The biosynthetic origin of compounds 1-5 was postulated. Compounds 1-5 exhibited no antibacterial activity against Staphylococcus aureus and Escherichia coli at the dose of 100 µM.