Scabrolides A-D, four new norditerpenoids isolated from the soft coral Sinularia scabra

Four new norditerpenoids, scabrolides A-D (1-4), along with four known ones, 5-8, have been isolated from the dichloromethane extract of the Taiwanese soft coral Sinularia scabra. The structures of 1-4 were elucidated on the basis of extensive spectroscopic analyses, while the relative configurations were determined by the NOESY experiments. The epimeric metabolites 6 and 7 have been shown to exhibit strong cytotoxic activity against KB and Hepa59T/VGH cancer cell lines.