Varioxiranols I-L, new lactones from a sponge-associated Emericella variecolor fungus.

Chemical examination of the sponge-associated fungus Emericella variecolor resulted in the isolation of four new lactones namely varioxiranols I-L(1-4)with different scaffolds, together with asteltoxin (5) and asteltoxin B (6). The structure elucidation of new compounds was accomplished by spectroscopic analysis, while the absolute configurations were determined by computed circular dichroism (ECD) and induced CD effects. Antitumor activities of these compounds were evaluated against different tumor cell lines, while the result indicated that the new compounds showed moderate cytotoxic activity against a panel of tumor cell lines.