Abstract
The basidiomycetes Stereum hirsutum and Boreostereum vibrans are two fungi of the same genus. In this study, chemical investigation on the co-cultures of the two congeneric fungi led to the isolation of eleven new vibralactone derivatives, hirsutavibrins A-K (1-11). The structures of 1-11 were elucidated by extensive NMR and HRESIMS spectroscopic analysis, and computational methods. Hirsutavibrins A (1) and B (2) showed weak cytotoxicity against the human lung cancer cell line A549. Hirsutavibrin D (4) showed moderate anti-nitric oxide activity in murine monocytic RAW 264.7 macrophages. This work not only expands the members of vibralactone derivatives with variable configurations but also opens a new avenue for fungal co-culturing study between congeneric fungi.