Constituents of the sea cucumber Cucumaria okhotensis. Structures of okhotosides B1-B3 and cytotoxic activities of some glycosides from this species.

Three new triterpene oligoglycosides, okhotosides B 1 ( 1), B 2 ( 2), and B 3 ( 3), have been isolated from the sea cucumber Cucumaria okhotensis along with the known compounds frondoside A ( 4), frondoside A 1, cucumarioside A 2-5, and koreoside A. The structures of 1- 3 were elucidated on the basis of their spectroscopic data (2D NMR and MS). Compounds 1- 3 were moderately toxic against HeLa tumor cells. Frondoside A ( 4) showed more potent cytotoxicity against THP-1 and HeLa tumor cell lines (with IC 50 values of 4.5 and 2.1 microg/mL, respectively) and decreased both the AP-1-dependent trascriptional activities induced by UVB, EGF, or TPA in JB6-LucAP-1 cells and the EGF-induced NF-kappaB-dependent transcriptional activity in JB6-LucNF-kB cells at doses of about 1 microg/mL. At the same doses, it increased the p53-dependent transcriptional activity in nonactivated JB6-Lucp53 cells and inhibited the colony formation of JB6 P (+) Cl 41 cells activated with EGF (INCC 50 = 0.8 microg/mL).