Potent inhibitors of histamine release: polyhydroxylated sterols from the Okinawan soft coral Sinularia abrupta.

A new polyhydroxylated steroid (24-methylene-1 alpha, 3 beta, 11 alpha-trihydroxycholest-5-ene-18-oic acid-3-acetate, 1) and known related compounds (2-4) from the soft coral Sinularia abrupta have potently inhibited histamine release from rat peritoneal mast cells induced by anti-immunoglobulin E. The inhibitory effect of 1 was approximately 6500 times stronger than that of disodium cromoglycate, a well-known antiallergic drug.