ANTICOMPLEMENTARY ACTIVITY OF BOSWELLIC ACIDS - AN INHIBITOR OF C3-CONVERTASE OF THE CLASSICAL COMPLEMENT PATHWAY

Boswellic acids (BA), an anti-inflammatory and anti-arthritic principle/s of Boswellia serrata, were found to possess anticomplementary activity. It inhibits the in vitro immunohaemolysis of antibody-coated sheep erythrocytes by pooled guinea-pig serum. The reduced immunohaemolysis was found to be due to inhibition of C3-convertase of the classical complement pathway. The threshold concentration for inhibiting C3-convertase was found to be 100-mu-g. However, higher concentrations of BA showed constant inhibitory effects- on immunohaemolysis. BA also exhibited weak inhibitory effects on individual components of the complement system. In vivo administration of BA also showed the inhibitory effect on guinea-pig serum.