9,11-Secosterols from the soft corals Sinularia lochmodes and Sinularia leptoclados

Chemical investigations on the EtOAc-soluble fractions from the EtOH extract of two Formosan soft corals afforded two new 9,11-secosteroids, 3 beta, 11-dihydroxy-5 beta, 6 beta-epoxy-24-methylene- 9,11-secocholestan-9-one (1) and 3 beta, 11-dihydroxy- 24-methylene-9,11-secocholestan-9-one (2), from Sinularia lochmodes and Sinularia leptoclados, respectively, along with two known analogues (3 and 4) from S. leptoclados. The structures of the new metabolites were elucidated on the basis of extensive spectroscopic analysis and by comparison of their NMR data with those of the known compound 3. The cytotoxicity of 2-4 toward a limited panel of cancer cell lines is also reported.