Four cembrenolides (1～4) were isolated from the soft coral sinularia capillosa collected around Sanya, Hainan Island, China. Compound (1), C~2~0H~3~2O~5, m.p.158～160℃, [α]~D^2^5+42.8°(c 0.05, EtOH) is a new compound. Its structure was elucidated on the basis of spectroscopic data. The relative stereochemistry of 1 was determined to be 1R^*, 4R^*, 5S^*, 12S^*, 13R^* mainly by NOESY and NOE difference spectra. Compound (4), flexibilide, exhibited potent cytotoxicity toward HepA and EAC cell lines.

Key words: SOFT CORAL, SPECTROMETRIC ANALYSIS