New Conjugates of Polyhydroxysteroids with Long-Chain Fatty Acids from the Deep-Water Far Eastern Starfish Ceramaster patagonicus and Their Anticancer Activity

Four new conjugates, esters of polyhydroxysteroids with long-chain fatty acids (1-4), were isolated from the deep-water Far Eastern starfish Ceramaster patagonicus. The structures of 1-4 were established by NMR and ESIMS techniques as well as chemical transformations. Unusual compounds 1-4 contain the same 5 alpha-cholestane-3 beta,6 beta,15 alpha,16 beta,26-pentahydroxysteroidal moiety and differ from each other in the fatty acid units: 5 ' Z,11 ' Z-octadecadienoic (1), 11 ' Z-octadecenoic (2), 5 ' Z,11 ' Z-eicosadienoic (3), and 7 ' Z-eicosenoic (4) acids. Previously, only one such steroid conjugate with a fatty acid was known from starfish. After 72 h of cell incubation, using MTS assay it was found that the concentrations of compounds 1, 2, and 3 that caused 50% inhibition of growth (IC50) of JB6 Cl41 cells were 81, 40, and 79 mu M, respectively; for MDA-MB-231 cells, IC50 of compounds 1, 2, and 3 were 74, 33, and 73 mu M, respectively; for HCT 116 cells, IC50 of compounds 1, 2, and 3 were 73, 31, and 71 mu M, respectively. Compound 4 was non-toxic against tested cell lines even in three days of treatment. Compound 2 (20 mu M) suppressed colony formation and migration of MDA-MB-231 and HCT 116 cells.