Effects of Phytosterols on Anti-complementary Activity

Abstract

Several phytosterols, stigmasterol, campesterol and β-sitosterol, were shown to have potent anti-complementary activities. Stigmasterol was the most potent. A marked consumption of C4 was observed to have occurred when serum was incubated with these phytosterols, and β-sitosterol and stigmasterol showed higher C4 consumption than campesterol. After the incubation of serum with these phytosterols in the absence of Ca2+ ions, cleavage of C3 in the serum was detected by immunoelectrophoresis. Stigmasterol caused greater C3 cleavage than the other two compounds. Stigmasterol also showed higher consumption of complement than campesterol and β-sitosterol when rabbit erythrocytes were used in the assay system in the absence of Ca2+ ions. These results indicate that these phytosterols activate complement via both the alternative and classical pathways. © 1987, The Pharmaceutical Society of Japan. All rights reserved.