Numerosol A-D, New Cembranoid Diterpenes from the Soft Coral Sinularia numerosa

Four new cembrane-type diterpenes; numerosol A-D (1-4); along with a known steroid; gibberoketosterol (5); were isolated from the Taiwanese soft coral Sinularia numerosa. The structures of these metabolites were determined by extensive analysis of spectroscopic data. Gibberoketosterol (5) exhibited cytotoxicity against P-388 (mouse lymphocytic leukemia) cell line with an ED50 of 6.9 mu M.