Natural clovanes from the gorgonian coral Rumphella antipathies.

Three natural clovane-related sesquiterpenoids, 2beta-acetoxyclovan-9alpha-ol (1), 9alpha-acetoxyclovan-2beta-ol (2) and clovan-2beta,9beta-diol (3), were isolated from the gorgonian coral Rumphella antipathies. The structures of clovanes 1-3 were elucidated by spectroscopic methods and by comparison of the spectral data with those of known clovane analogues. This is the first time that clovanes 1-3 have been isolated from a natural source. Clovanes 1 and 2 displayed inhibitory effects on the generation of superoxide anions and the release of elastase by human neutrophils.