Stereumins K-P, sesquiterpenes from the fungus Stereum sp. CCTCC AF 2012007.

The basidiomycete genus Stereum fam Stereaceae is a rich source of sesquiterpenoids. This phytochemical investigation of the basidiomycete Stereum sp. CCTCC AF 2012007 led to isolation of six cadinane-type sesquiterpenes named stereumins K-P. Stereumin O was very likely an artifact formed from stereumin N during isolation. Their structures were elucidated mainly by 1D and 2D NMR spectroscopy. Structures of stereumins K, L, M and P were further confirmed by single-crystal X-ray diffraction, and the absolute configuration of stereumin K was determined.