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

Four new conjugates, esters of polyhydroxysteroids with long-chain fatty acids (-), were isolated from the deep-water Far Eastern starfish Ceramaster patagonicus The structures of - were established by NMR and ESIMS techniques as well as chemical transformations. Unusual compounds - contain the same 5α-cholestane-3β,6β,15α,16β,26-pentahydroxysteroidal moiety and differ from each other in the fatty acid units: 5'Z,11'Z-octadecadienoic (), 11'Z-octadecenoic (), 5'Z,11'Z-eicosadienoic (), and 7'Z-eicosenoic () 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 , , and that caused 50% inhibition of growth (IC) of JB6 Cl41 cells were 81, 40, and 79 µM, respectively; for MDA-MB-231 cells, IC of compounds , , and were 74, 33, and 73 µM, respectively; for HCT 116 cells, IC of compounds , , and were 73, 31, and 71 µM, respectively. Compound 4 was non-toxic against tested cell lines even in three days of treatment. Compound (20 µM) suppressed colony formation and migration of MDA-MB-231 and HCT 116 cells.