New cytotoxic steroids from the Indian ocean sponge Axinella cf. bidderi

Four new sterols have been isolated from the marine sponge Axinella cf. bidderi, 17alpha-hydroxy-22,23-epoxy-24-methylcholest-5-en-3beta- ol (1) and 17alpha-hydroxy-22,23-epoxycholest-5-en-beta-ol (2), together with 3 and 4, which possess respectively the cholestene and the cholestane skeleton with a cyclic enol ether linkage between C-18 and C-22. The structures were elucidated using spectroscopic data. The in vitro activity was evaluated against prostate, ovary, pancreas, colon, and lung cell lines.