Immunomodulatory activity of Boswellic acids (Pentacyclic triterpene acids) from Boswellia serrata

Boswellic acids, a mixture of pentacyclic triterpene acids (BA) obtained from Boswellia serrata Roxb., have been investigated for their effect on cell mediated and humoral components of the immune system and the immunotoxicological potential. A single oral administration of BA (50-200 mg/kg) inhibited the expression of the 24 h delayed type hypersensitivity (DTH) reaction and primary humoral response to SRBC in mice. The secondary response was appreciably enhanced at lower doses. In a multiple oral dose schedule BA (25, 50 and 100 mg/kg) reduced the development of the 24 h DTH reaction and complement fixing antibody titres and slightly enhanced the humoral antibody synthesis. In concentrations greater than 3.9 mu g/mL BA produced almost similar and dose related inhibition of proliferative responsiveness of splenocytes to mitogens and alloantigen. Preincubation of macrophages with different concentrations of BA enhanced the phagocytic function of adherent macrophages. Prolonged oral administration of BA (25-100 mg/kg/d X 21 days) increased the body weight, total leukocyte counts and humoral antibody titres in rats. It is not cytotoxic nor does it cause immunosuppression.