Crassocolides G-M, cembranoids from the Formosan soft coral Sarcophyton crassocaule.

Seven new polyoxygenated cembranoids possessing an alpha-methylene-gamma-lactone group, crassocolides G-M (1-7, resp.), have been isolated from the AcOEt extract of the Formosan soft coral Sarcophyton crassocaule. The structures of compounds 1-7 were established by detailed spectroscopic analyses, including 2D-NMR spectroscopy ((1)H,(1)H-COSY, HMQC, HMBC, and NOESY), while the absolute configuration of 1 was determined using a modified reaction of Mosher's method. The cytotoxicity of compounds 1-7 against a limited panel of cancer cell lines was also determined.