Structures and Bioactivities of Psolusosides B, B, J, K, L, M, N, O, P, and Q from the Sea Cucumber . The First Finding of Tetrasulfated Marine Low Molecular Weight Metabolites.

Ten new di-, tri- and tetrasulfated triterpene glycosides, psolusosides B (), B (), J (), K (), L (), M (), N (), O (), P (), and Q (), were isolated from the sea cucumber collected in the Sea of Okhotsk near the Kurile Islands. Structures of these glycosides were established by two-dimensional (2D) NMR spectroscopy and HR-ESI mass-spectrometry. It is particularly interesting that highly polar compounds and contain four sulfate groups in their carbohydrate moieties, including two sulfates in the same terminal glucose residue. Glycoside has an unusual non-holostane aglycone with 18(16)-lactone and a unique 7,8-epoxy fragment. Cytotoxic activities of compounds - against several mouse cell lines such as Ehrlich ascites carcinoma cells, neuroblastoma Neuro 2A, normal epithelial JB-6 cells, and erythrocytes were quite different depending both on structural peculiarities of these glycosides and the type of cells subjected to their actions. Psolusoside L (), pentaoside, with three sulfate groups at C-6 of two glucose and one 3--methylglucose residue and holostane aglycone, is the most active compound in the series. The presence of a sulfate group at C-2 of the terminal glucose residue attached to C-4 of the first (xylose) residue significantly decreases activities of the corresponding glycosides. Psolusosides of group B (, and known psolusoside B) are inactive in all tests due to the presence of non-holostane aglycones and tetrasaccharide-branched sugar chains sulfated by C-2 of Glc4.