ANTI-INFLAMMATORY AND ANTIOXIDANT EFFECTS OF THE STEM BARK AQUEOUS EXTRACT OF RAUWOLFIA VOMITORIA (APOCYNACEAE) IN FEMALE WISTAR RATS

Youmbie Djanche Duplex Bonheur*, Dzeufiet Djomeni Paul Désiré, Nkwengoua Zondegoumba Ernestine, Zingue Stéphane5, Mezui Christophe, Bibi Farouck Aboubakar Oumarou, Tankeu Nzufo Francine, Pieme Constant Anatole, Dimo Théophile*

ABSTRACT

Rauwolfia vomitoria is widely used in African traditional medical practice in the treatment of several inflammatory-related disorders. Since, several studies have suggested that the etiology of inflammation can partly be explained by oxidative stress, this study was directed to evaluate the anti-inflammatory and antioxydant effects of the stem bark aqueous extract of Rauwolfia vomitoria in female Wistar rats. In sub-chronic study, cotton pellet and carrageenan induced granuloma as well as formalin induced paw oedema models were used to evaluate the anti-inflammatory potential of the plant extract. For the chronic model, we assessed the effect of the extract against Complete Freund’s Adjuvant (CFA) induced inflammation. Administration of the aqueous extract (300 mg/kg) significantly reduced the formation of humid (31.25%) and dry (28.49%) granuloma in cotton pellet method compared with control. At the same dose, the plant extract also exhibited a significant sub-chronic anti-inflammatory effect by decreasing exudate volume (38.46%) and leukocytes number (53.68%) in air pouch test, and by reducing the paw oedema (49.60%) induced by formalin. Daily oral administration of the extract (300 mg/kg) or dexamethasone (1 mg/kg) for 10 and 12 days significantly inhibited by 55.98% and by 74.41% the paw eodema induced by formalin and CFA respectively when compared to control groups. CFA used alone significantly decreased reduced glutathione (GSH) level as well as superoxide dismutase (SOD) and catalase (CAT) activities in liver, kidney and spleen when compared to normal rats. Treatment with Rauwolfia vomitoria extract and dexamethasone significantly restored GSH, SOD and CAT in all investigated tissues. In addition, the plant extract significantly restored malondialdehyde (MDA), protein and nitrite concentrations in serum and tissues (liver, spleen and kidney) by reducing their content, as compared to CFA control group. Keeping in this view, the data suggest that Rauwolfia vomitoria aqueous extract may possess anti-inflammatory and antioxidant effects.

Keywords: Rauwolfia vomitoria, inflammation, Complete Freund’s Adjuvant, anti-oxidant, granuloma.