New cytotoxic cembranolides from the soft coral Lobophytum michaelae

Eleven new cytotoxic cembranolides, michaolides A-K (1-11), and crassolide (12) were isolated from the CH2Cl2 extract of the Formosan soft coral Lobophytum michaelae. Their structures were established by extensive spectral analysis. The cytotoxicity of the isolates against selected cancer cells was measured in vitro.