5,8-epidioxysterols and related derivatives from a Chinese soft coral Sinularia flexibilis

Chromatographic separation of the methanolic extract of the marine soft coral, Sinularia flexibilis, resulted in the isolation and characterization of four new sterols, 5 alpha,8 alpha-epidioxygorgosta-6-en-3 beta-omicron l (1), 5 alpha,8 alpha-epidioxygorgosta-6,9(11)-dien-3 beta-omicron l (2), 22 alpha,28-epidioxycholesta-5,23(Epsilon)-dien-3 beta-omicron l (3) and its C-22 epimer (4), along with nine known sterols. The structures of the new compounds were determined on the basis of extensive spectroscopic data (IR, MS, H-1 and C-13 NMR, HMQC, HMBC, and NOESY) analyses. (C) 2006 Elsevier Inc. All rights reserved.