The Composition of Triterpene Glycosides in the Sea Cucumber Psolus peronii : Anticancer Activity of the Glycosides against Three Human Breast Cancer Cell Lines and Quantitative Structure-Activity Relationships (QSAR).

Eight sulfated triterpene glycosides, peronioside A ( 1 ) and psolusosides A ( 2 ), B ( 3 ), G ( 4 ), I ( 5 ), L ( 6 ), N ( 7 ) and P ( 8 ), were isolated from the sea cucumber Psolus peronii . Peronioside A ( 1 ) is a new glycoside, while compounds 2 - 8 were found previously in Psolus fabricii , indicating the phylogenetic and systematic closeness of these species of sea cucumbers. The activity of 1 - 8 against human erythrocytes and their cytotoxicity against the breast cancer cell lines MCF-7, T-47D and triple-negative MDA-MB-231 were tested. The most active against cancer cell compounds, psolusosides A ( 2 ) and L ( 6 ), which were not cytotoxic to the non-transformed cells of the mammary gland, were chosen to study the inhibition of the migration, formation and growth of colonies of the cancer cell lines. Glycoside 2 effectively inhibited the growth of colonies and the migration of the MDA-MB-231 cell line. Compound 6 blocked the growth of colonies of T-47D cells and showed a pronounced antimigration effect on MDA-MB-231 cells. The quantitative structure-activity relationships (QSAR) indicated the strong impact on the activity of the form and size of the molecules, which is connected to the length and architecture of the carbohydrate chain, the distribution of charge on the molecules' surface and various aspects of hydrogen bond formation, depending on the quantity and positions of the sulfate groups. The QSAR calculations were in good accordance with the observed SAR tendencies.