Novel terpenoids from the formosan soft coral Cespitularia hypotentaculata

Four new cytotoxic diterpenes, cespitularins A-D (1-4), having the verticillane skeleton, a new cytotoxic norditerpene, cesputularin E (5), that possesses a novel norverticillane skeleton, and three new diterpenes, cespitularins F-H (6-8), possessing a novel carbon skeleton named cespitularane, were isolated from the methylene chloride solubles of the Formosan soft coral Cespitularia hypotentaculata. The structures of cespitularins A-H (1-8) were elucidated by 1D and 2D NMR spectral analysis, and their cytotoxicity against selected cancer cells was measured in vitro.