NEW OXYGENATED SESQUITERPENES FROM THE INDONESIAN SOFT CORAL NEPHTHEA-CHABROLII

The Indonesian soft coral Nephthea chabrolii afforded two new oxygenat ed sesquiterpenes: hydroxycolorenone (1) and methoxycolorenone (2), as well as the known liverwort metabolite (+)-cyclocolorenone (3). This is the first report of the occurrence of such terrestrial liverwort me tabolites in marine soft corals. The structures of the new compounds w ere unambiguously established an the basis of NMR spectroscopic data ( H-1, C-13, COSY, H-1-defected direct and long-range C-13-H-1 correlati ons). Compound 1 exhibited insecticidal activity towards neonate larva e of the polyphagous pest insect Spodoptera littoralis, with an EC50 o f 8.8 ppm and a LC50 of 453 ppm, when incorporated in artificial diet and offered to larvae in a chronic feeding bioassay.