Antioxidant Effects of Vernonia amygdalina Leaf Extract on 1,2-Dimethylhydrazine-Induced Colon Toxicity in Rats

Background and Objective: Reported to possess different biological effects, the medicinal plant Vernonia amygdalina (bitter leaf) is perceived as a wonder herb by locals. The study aims to investigate the antioxidant properties of Vernonia amygdalina leaf extract on 1,2-dimethylhydrazine-induced colon toxicity in rats. Materials and Methods: Forty male Wistar albino rats weighing 150-200 g were assigned to 8 groups (5 rats per group): Control, DMH, silymarin, VA only, pretreatment (200 mg/kg b.wt.), pretreatment (400 mg/kg b.wt.), post-treatment (200 mg/kg b.wt.), and post-treatment (400 mg/kg b.wt.) groups, respectively. Except control and VA only groups, the rats were exposed to DMH before or after treatment with VA via the intraperitoneal route at a single dose of 40 mg/kg b.wt.). Treatment lasted 21 days. Results: That there were significant reductions (p<0.05) in the concentrations of colon tissue antioxidant enzymes (CAT, SOD, GPx, GSH, GR and GSH (%)) relative to control and the other groups. However, administration of ethanol extract of V. amygdalina to rats significantly increased (p<0.05) the levels of the antioxidant enzymes when compared with the DMH group. Consequently, there was a significant decrease (p<0.05) in the mean values of Colon Total Protein (TP), Nitric Oxide (NO), and Malondialdehyde (MDA) in the treatment groups relative to the control and DMH groups. Colon tissues of DMH-induced rats treated with Vernonia amygdalina revealed a significant reduction (p<0.05) in organ weight relative to the DMH group. Histological studies revealed the protective and regenerative effects of Vernonia amygdalina on colon tissues. Conclusions: The findings from this study provided an insight into the therapeutic properties of Vernonia amygdalina and could serve as a benchmark for further studies