Four new saponins from the starfish Certonardoa semiregularis

Four new saponins, designated as certonardosides K-N (1-3, 5), were isolated, along with culcitoside C(6) (4), from the brine shrimp active fraction of the starfish Certonardoa semiregularis. The structures were determined on the basis of spectral analysis and chemical derivatization. These compounds were evaluated for cytotoxicity and antibacterial activity.