Cytotoxic sesquiterpenoid quinones from South China Sea sponge Dysidea sp.

A new sesquiterpene, (+)-19-methylaminoavarone ( 1 ), together with six known compounds ( 2 - 7 ), were isolated from the Xisha Islands marine sponge Dysidea sp. The structures were elucidated based on their spectroscopic data. We revised the carbon spectrum data of the compound 2 . The absolute configurations of compounds 1 and 2 were further confirmed by electronic circular dichroism (ECD) analysis. Compounds 1 - 3 and 5-7 showed potent cytotoxic activity against several human cancer cell lines.