Effects of oleanolic acid on immune system and type I allergic reaction

Oleanolic acid (OLA)50, 100 mg/kg sc antagonised the inhibitory effect of cortisone on the weights of spleen and thymus, decreased the clearance rate of charcoal particles in mice. The production of serum specific antibody hemolysin was not clearly affected by OLA. The administration of OLA 100 mg/kg enhanced the development of serum antibody immunoglobulin G in mice and showed marked inhibition on the hemolytic activity of the total complement by classical pathway in guinea pigs. In addition, the homologous passive cutaneous anaphylaxis in mice or rats and the degranulation of mast cells of calvarial periosteum in rats were significantly prevented by OLA 50, 100 mg/kg. The increased capillary permeability in the rat skin caused by intradermic injection of histamine was also reduced by OLA 100 mg/kg. These results indicate that OLA inhibited the type I allergic reaction.