Complete Freund’s adjuvant-induced arthritis in rats: Anti-inflammatory and antioxidant properties of Allanblackia gabonensis (guttiferae) aqueous extract

Allanblackia gabonensis (Guttiferae) stem bark extract is generally used in Cameroonian traditional medicine for its beneficial activities as antibiotics, anti-inflammatory, and antinociceptive. However, the claimed chronic anti-inflammatory and antioxidant effects have not yet been largely elucidated scientifically. The present study was designed to evaluate the anti-inflammatory and antioxidant effects of A. gabonensis stem bark aqueous extract on Freund’s complete adjuvant (CFA)-induced arthritis in rats. Arthritis was induced by intradermal injection of CFA (0.1 mL) into the right hind paw of each rat. Pain relieving effects were measured in the treated animals using an analgesiometer and antioxidant activity determined by measuring oxidative stress parameters. In addition, the hematological index, serum nitric oxide (NO), and transaminase activities were evaluated in the experimental animals. A. gabonensis significantly protected animals against pain from day 15 to 18 and decreased (P < 0.01) the paw edema from day 12 to the end of the experimentation (day 22). The number of white blood cells increased while the NO levels in serum and organs decreased in CFA animals as compared to the control group. An increase in serum transaminases was observed in the CFA group. A. gabonensis at the dose of 200 mg/kg significantly increased (36.36%) glutathione levels in the spleen in comparison with the CFA group. There was also a significant increase (P < 0.01) of liver and cardiac catalase in animals receiving extract at 100 and 200 mg/kg. Our findings revealed the anti-arthritic and antioxidant potential of A. gabonensis and, thus, validate its traditional claim.