(-)-Hydroxylindestrenolide, a new sesquiterpenoid from a gorgonian coral Menella sp. (Plexauridae).

(-)-Hydroxylindestrenolide (1), an enantiomer of the known sesquiterpenoid, (+)-hydroxylindestrenolide (2), was isolated from a gorgonian coral identified as Menella sp. The structure, including the relative stereochemistry of 1 was established by spectroscopic methods and by comparison the spectral and physical data with those of 2. Sesquiterpenoid 1 exhibited marginal cytotoxicity toward HL-60 and K562 leukemia tumor cells, and displayed a weak inhibitory effect on superoxide anion generation at a concentration of 10 µg/ml by human neutrophils.