During the chemical investigation of a new species of soft coral belonging to the genus Sarcophyton, two novel cembranoid compounds with a 12Z double bond (1 and 2) were obtained. Determination of the double bond configurations was done using NMR spectroscopic data and the results of molecular modeling studies. Compound 3, one of several known compounds (3–5), was found to be cytotoxic toward an MCF7 tumor cell line.

Additionally, we report the absolute stereochemistry of the cembrane sarcoglaucol-16-one (6), which was determined using the modified Mosher′s method.