CYTOTOXIC TRITERPENE GLYCOSIDES FROM FAR-EASTERN SEA-CUCUMBERS BELONGING TO THE GENUS CUCUMARIA

New cytotoxic triterpene oligoglycoside disulfates, cucumariosides A(3 ) (1) and A(6)-2 (2), have been isolated from the sea cucumber Cucumar ia japonica. The trisulfated cucumarioside A(7)-3 (4) was found to be the major component in the glycoside fraction of Cucumaria miniata. Th e structures were assigned on the basis of extensive spectral data (NM R and MS), selective solvolysis of desulfated derivative 3 and other c hemical evidence. The presence or absence of a carbonyl group at C-16 of the aglycone and of sulfate groups at C-6 of the glucose and 3-O-me thylglucose units are interpreted in terms of the functional evolution of sea cucumbers in order to improve their defensive system. Both (1) and (2) are cytotoxic in vitro at IC50 = 1 mu g/ml against a selectio n of five human and mice tumoral cell lines.