Free sterols from the holothurians Synapta maculata, Cladolabes bifurcatus and Cucumaria sp.

Abstract Free sterol fractions from the holothurians (sea cucumbers) Synapta maculata , Cladolabes bifurcatus and Cucumaria sp. have been isolated and studied by HPLC, GLC, GLC-MS and NMR methods. Forty seven sterols were identified, including several rare ones. In contrast with previously studied holothurians, the presence of a minor amount of Δ 7 sterols was indicated in the sterols of S. maculata . This animal contains predominantly Δ 9(11) sterols as well as an abnormally high concentration of Δ 5 sterols. In C. bifurcatus and Cucumaria sp., 14α-methyl and 4α,14α-dimethyl-Δ 9(11) sterols were found to be the main sterol constituents. Peculiarities of sterol distribution and the relationship between sterol compositions and taxonomic positions, ecology and toxicity of the corresponding sea cucumbers were discussed.