Effects of Aqueous and Methanolic Extracts of Stem Bark of De Wild. (Apocynaceae) on Dextran Sodium Sulfate-Induced Ulcerative Colitis in Wistar Rats.

Among the most exploited species in Cameroon, is widely used in African medicine for the relief of several pathologies including gastrointestinal disorders. This study was conducted in order to assess the effects of aqueous and methanol stem-bark extracts of on DSS- (dextran sodium sulfate-) induced intestinal colitis and to determine its antioxidant potential. The classes of secondary metabolites present in these extracts were determined by chemical screening. The production of TNF-, IL-6, IL-1, and PGE2 was performed by ELISA analysis. Anticolitis effects were determined using an model of ulcerative colitis induced by DSS. The colitis was induced with a double dose of DSS (3% and 1%), and the aqueous and methanol extracts were administered orally from the 6 day after commencement of induction. The phytochemical screening revealed the presence of six classes of secondary metabolites in these crude extracts: tannins, saponins, alkaloids, steroids, flavonoids, and phenols. Methanol and aqueous extracts of significantly ( < 0.001) inhibited TNF-, IL-6, IL-1, and PGE2 production stimulated by LPS. Both extracts at all doses significantly reduced ( < 0.01, < 0.001) the signs of DSS-induced colitis in the Wistar rats by decreasing inflammation and chronic colon damage. In addition, the extracts significantly ( < 0.001) reduced malondialdehyde and nitric oxide levels in the colon and significantly ( < 0.01) increased superoxide dismutase and catalase and reduced glutathione ( < 0.05). Both extracts showed greater activity than the reference substance (prednisolone 4 mg/kg) used in this study. This study has demonstrated that aqueous and methanol extracts of stem bark have healing properties against colitis experimentally induced by DSS in rats.