Monalbidins A-E, Decalins with Potential Cytotoxic Activities from Marine Derived Fungus Monascus albidus BB3.

Five new decalins, monalbidins A-E ( 1 , 2 and 7 - 9 ), together with 16 known compounds ( 3 - 6 and 10 - 21 ), were isolated from the EtOAc extract of marine derived fungus Monascus albidus BB3 cultured in GPY medium. Among the known compounds, 1-hydroxymonacolin L ( 11 ), dehydromonacolin J ( 15 ), 8- O -acetylmonacolin J ( 19 ) and O -acetylmonacolin K ( 21 ) were separated from natural sources for the first time.Their structures were determined by comprehensive analysis on the 1D and 2D NMR, HRESIMS, UV and IR data , and their absolute configurations were assigned by experimental and calculated ECD data, and X-ray single-crystal diffraction analysis. Monalbidins C and D ( 7 and 8 ), monacolin K methyl ester ( 13 ), dehydromonacolin L ( 14 ), dehydromonacolin K ( 16 ), monacolin K ( 20 ) and O -acetylmonacolin K ( 21 ) showed moderate cytotoxicity against human cancer cell lines SUNE1, HepG2, QGY7701, HCT116 and MDA-MB-231.