Steroids and sesquiterpenoids from the soft corals Dendronephthya gigantea and Lemnalia cervicorni

One new cytotoxic steroid, dendronesterone A (1), two new steroids, dendronesterones B and C (2 and 3), and a known steroid (4) were isolated from the methylene chloride solubles of the Formosan soft coral Dendronephthya gigantea. Two cytotoxic ylangene-type sesquiterpenoids, lemnalol (5) and the new compound cervicol (6), as well as two ylangene-type sesquiterpenoids, isolemnalol (7) (a new compound) and 4-oxo-alpha-ylangene (8), were isolated from the methylene chloride solubles of the Formosan soft coral Lemnalia cervicorni. Their structures were elucidated by 1D and 2D NMR spectral analysis, and their cytotoxicity against selected cancer cells was measured in vitro.