Characteristic Steroids from the South China Sea Gorgonian Muricella sibogae and Their Cytotoxicities

摘要

Twenty-four steroid-based natural products, 9,10-secosteroids (1-10), 1,4-dien-3-one steroids (11-19), and 4-en-3-one steroids (20-24), containing varying side-chains, were isolated from the South China Sea gorgonian Muricella sibogae. The structures of one new 9,10-secosteroid, sibogol D (1), and two new 1,4-dien-3-one steroids, sibogols E and F (11 and 12), were elucidated by extensive spectroscopic analyses and by comparison with the literature data. Cytotoxicities for all the isolates were evaluated against four selected tumor cell lines, HL-60, HCT116, K562, and P388. Compounds 3, 9, and 13 exhibited potent cytotoxic activities against the HL-60 cell line, with IC50 values ranging from 1.27 to 10.05M, and compound 3 was also cytotoxic against HCT116 with an IC50 value of 5.8M. The bioassay results also indicated a potential relationship between structural patterns and activity. The newly presented series of 1,4-dien-3-one and 4-en-3-one types of steroids relating to the unique 9,10-secosteroids in biogenesis were found in this species for the first time, which is of considerable chemotaxonomic significance.