Sesquiterpenoids From the Antarctic Fungus sp. HSX2#-11.

The fungal strains are a kind of psychrophilic pathogenic fungi that are ubiquitously distributed in Antarctica, while the studies of their secondary metabolites are infrequent. Systematic research of the metabolites of the fungus sp. HSX2#-11 led to the isolation of six new tremulane sesquiterpenoids pseudotremulanes A-F (-), combined with one known analog 11,12-epoxy-12β-hydroxy-1-tremulen-5-one (), and five known steroids (-). The absolute configurations of the new compounds (-) were elucidated by their ECD spectra and ECD calculations. Compounds - were proved to be isomeride structures with the same chemical formula. Compounds /, /, /, and / were identified as four pairs of epimerides at the locations of C-3, C-3, C-9, and C-9, respectively. Compounds and exhibited cytotoxic activities against human breast cancer (MDA-MB-231), colorectal cancer (HCT116), and hepatoma (HepG2) cell lines. Compounds and also showed antibacterial activities against marine fouling bacteria . This is the first time to find terpenoids and steroids in the fungal genus .