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.