STUDIES ON ANTI-INFLAMMATORY EFFECTS OF SOME ACACIA SPECIES

In vitro anti-inflammatory activities of dichloromethane (DCM) and 90% methanol (MeOH) extracts of bark and leaves of three Acacia species were investigated using both cyclooxygenase-1 (COX-1) and cyclooxygenase –2 (COX-2) enzymes. The plants investigated were:, A. nilotica, A. nubica and A. senegal. The results showed that DCM bark extracts of all species had high COX-2 selective inhibition (IC50 values of 0.45, 37 and 17.3 ï­g/mL) compared to COX-1 inhibition (IC50 values of 206.3, >250, >250 ï­g/mL) respectively. The DCM bark extracts of the three species were evaluated further in vivo in rats with adjuvant-induced arthritis. DCM bark extracts of A. senegal significantly reduced the edema when administered at a dose of 300 mg/kg (p < 0.05). The extract did not cause lesions in the gastrointestinal mucosa compared to indomethacin which caused severe lesions in the small intestine (ulcer index = 194.3±2.7 mm2). On the other hand, DCM bark extracts of A. nubica and A. nilotica were not active in in vivo assay. The results suggest that DCM bark extracts of A. senegal subsp. senegal may be useful in the treatment of rheumatoid arthritis. Acknowledgements: Japanese Society for Promotion of Science (JSPS) for financial support