Steroids from the Soft Coral Sinularia crassa

One new sterol, crassarosterol A (1), and four new steroidal glycosides, crassarosterosides A-D (2-5) were isolated from the Formosan soft coral Sinularia crassa. The absolute configuration of 1 was determined using the Mosher's method. The absolute configurations for the sugar moieties of 2-5 were determined by HPLC analysis on the o-tolylthiocarbamates derived from the liberated sugar after acid hydrolysis. Compounds 2 and 4 could significantly inhibit the expression of pro-inflammatory iNOS protein at 10 mu M. In contrast, 1-3 were found to stimulate the expression of COX-2 protein at this concentration. Steroids 1 and 4 also showed cytotoxicity toward the selected human liver cancer cells.