HOLOTHURINOSIDES - NEW ANTITUMOR NONSULFATED TRITERPENOID GLYCOSIDES FROM THE SEA-CUCUMBER HOLOTHURIA-FORSKALII

Five triterpene glycosides (holothurinosides A, B, C and D; 1, 2, 3 and 5 respectively) and desholothurin A (4) have been isolated from the sea cucumber Holothuria forskalii. Compounds 1 and 2 are the first non-sulphated pentasaccharide saponins isolated from marine echinoderms. 3 and 5 are di and tetrasaccharides, and 4 is a tetrasaccharide that has been described as a synthetic intermediate. The structures were established by FAB-MS, COSY, NOESY and long range and direct XHCORR experiments, and selective hydrolysis. 1-5 and the related saponin 6 have antitumour and antiviral activity, 1 and 4 being the most active with IC50 values of 0.46 and 0.38 mg/ml respectively for P388 cells.