Nakiterpiosin, a novel cytotoxic C-nor-D-homosteroid from the Okinawan sponge Terpios hoshinota

A novel cytotoxic compound, nakiterpiosin (1), was isolated from the Okinawan sponge Terpios hoshinota. Its structure was determined by spectroscopic analysis. The absolute stereostructure of 1 was also determined by a modified Mosher's method. Nakiterpiosin showed potent cytotoxicity against P388 cells.