Steroid and cembranoids from the Dongsha atoll soft coral Lobophytum sarcophytoides

A novel sterol, sarcophytosterol (1), and four new cembranoids, sarcophytolins A-D (2-5), have been isolated from the soft coral Lobophytum sarcophytoides along with four known metabolites 6-9. The relative structures of new metabolites were elucidated on the basis of extensive spectroscopic analyses and X-ray diffraction analysis of 1, and the absolute configurations of 1 and 5 were determined by Mosher's method and CD spectrum, respectively. Compound 1 is a steroid possessing an unusual (20R,23R,24R)-23,24-dimethyl-20-hydroxy side chain. Compounds 3, 6, 8, and 9 were shown to exhibit cytotoxicity toward a limited panel of cancer cell lines. Furthermore, while 1 could effectively enhance the expression of the pro-inflammatory iNOS protein in LPS-stimulated RAW264.7 macrophage cells, compounds 2, 3, 5-7 and 9 were found to effectively inhibit the accumulation of the pro-inflammatory of iNOS. (C) 2010 Elsevier Ltd. All rights reserved.