Effect of alpha-amyrin palmitate on adjuvant arthritis.

alpha-amyrin palmitate was synthesized and tested on adult male Wistar rats made arthritic by subplantar injection of complete Freund's adjuvant. When administered orally at 66 mg/kg BW every 48 h for 5 days from days 32 to 40 post-adjuvant and assessed on day 50, alpha-amyrin palmitate returned the increases in serum hyaluronate and blood granulocytes toward non-arthritic levels and corrected the moderate anaemia of adjuvant arthritis. Histological examinations of the second and third proximal foot interphalangeal joints showed reduced synovial proliferation and invasion of joints and reduced leucocyte infiltration of bone marrow in alpha-amyrin palmitate-treated rats. In addition, the drug prevented or reduced bone (subchondral or cortical) and cartilage (articular) destruction in arthritic rats. The results suggest that alpha-amyrin palmitate is antiarthritic in the adjuvant model of arthritis in rats.