In Vitro Antioxidant and Anti-arthritic Activity of the Aqueous Extract of the Bark of Distemonanthus benthamianus (Caesalpiniaceae) on Wistars Rats

Distemonanthus benthamianus is a plant of the Caesalpiniaceae family, used in traditional medicine to treat inflammatory problems such as rheumatism, bronchitis, epilepsy, and boils. The objective of the present work is to develop the pharmacological properties of this plant by evaluating the antioxidant (in vitro) and anti-arthritic properties of the bark of the plant on wistar rat. The antioxidant activity of the extract was evaluated by determining the antiradical activity through the DPPH radical scavenging test and the reducing activity of the extract. The anti-arthritic activity of the extract was evaluated on Wistars rats. Arthritis was induced in rats by injection of Freud's complete adjuvant in the plantar fascia of the left leg of the rats. The reducing power and the IC50 of the extract were 426.0±17.31 µmol Eq/Trolox/g EXS and 26.67±1.12 µg/mL, respectively. The plant extract and reference molecules administered to arthritic rats significantly reduced edema and arthritic signs. The weight of the rats was quickly stabilized at the level of the treated rats. At the end of the experiment, the percentages of inhibition of the extract at the doses of 200, 400, 800 mg/kg/bw were respectively 38.2%, 44.33% and 48%. As for the molecules of diclofenac sodium and Prednisone (5 mg/kg/bw), the percentages of inhibition were 47.33% and 37.84% respectively. A part from the reduction of edema, the hematological (leukocytes, platelets) and biochemical (fibrinogen, total protein, albumin, total and conjugated bilirubin, AST, ALT) parameters evaluated in treated rats showed no significant difference compared to healthy rats. These results confirm the traditional use of Distemonanthus benthamianus bark in cases of chronic inflammatory diseases.