Novel Cytotoxic Oxygenated C29 Sterols from the Colombian Marine Sponge <i>Polymastia </i><i>t</i><i>enax</i>

Abstract

Three new sterols, 5alpha,6alpha-epoxy-24R-ethylcholest-8(14)-en-3beta,7alpha-diol (1), 5alpha,6alpha-epoxy-24R-ethylcholest-8-en-3beta,7alpha-diol (2), and 3beta-hydroxy-24R-ethylcholesta-5,8-dien-7-one (3), have been isolated from the marine sponge Polymastia tenax, collected in the Colombian Caribbean, and their structures established on the basis of extensive NMR and MS studies. Compounds 1 and 2 showed antiproliferative activity toward A-549, HT-29, H-116, MS-1, and PC-3 tumor cells in the range 0.5-10 microg/mL.