ANTI-COMPLEMENT ACTIVITY OF OLEANOLIC ACID - AN INHIBITOR OF C-3-CONVERTASE OF THE CLASSICAL COMPLEMENT PATHWAY

Oleanolic acid is a naturally occurring compound, isolated from Luffa cylindrica, which inhibits the in-vitro immunohaemolysis of antibody-c oated sheep erythrocytes by guinea-pig serum. In further experiments t his reduced immunohaemolysis was found to be due to inhibition of the C-3-convertase of the classical complement pathway. The threshold conc entration for inhibition of C-3-convertase was 100 mu g mL(-1). Howeve r, higher concentrations of oleanolic acid showed constant inhibitory effects on immunohaemolysis. Oleanolic acid also exhibited weak inhibi tory effects on individual components of the complement system.