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 131 (1), 132 (2), and 133 (3), have been isolated from the sea cucumber Cucumaria okhotensis along with the known compounds frondoside A (4), frondoside A,, 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 mu g/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-kappa B-dependent transcriptional activity in JB6-LucNF-kappa B cells at doses of about 1 mu g/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 mu g/mL).