Effect of the leaves of Psidium guajava Linn. on experimentally induced colitis in animal models

Abstract

The aim of this study is to evaluate the effect of the ethanolic extract of the leaves of Psidium guajava (PGE) on experimentally induced colitis in animal models. Fresh tender leaves of the plant were collected, air-dried, powdered and percolated in 95% ethanol. Acute toxicity test was done according to Organization for Economic Cooperation and Development guidelines. Five groups of animals of the species Rattus norvegicus, of either sex, weighing 150–200 g, were taken for the study (n=6). Group A and Group B consisted of normal and experimental control animals (3% gum acacia, 10 ml/kg body weight), respectively. Group C and Group D were test groups (PGE 250 mg/kg body weight and PGE 500 mg/kg body weight, respectively) and Group E was administered standard [5-amino salicylic acid (5-ASA) 100 mg/kg body weight]. All animals were pretreated with the respective drugs for 5 days. Colitis was induced next morning in Groups B, C, D and E by administration of 1 ml of 4% acetic acid transrectally. All the animals were sacrificed 48 hours after colitis induction and distal 10 cm of the colon was resected. Colon was weighed for Disease Activity Index (DAI), and scored macroscopically and microscopically. Biochemical assessment included myeloperoxidase (MPO), tissue catalase (CAT), glutathione (GSH) and superoxide dismutase (SOD) estimation. Statistical analysis was done by one way analysis of variance, followed by multiple comparison tests. Groups C, D, and E showed a significant (P<0.05) decrease in DAI, and macroscopic and microscopic lesion score, as well as a significant improvement (P<0.05) in MPO, CAT, GSH and SOD levels as compared to Group B. The ethanolic extract of P. guajava leaves showed significant amelioration of experimentally induced colitis, which may be attributed to its anti-inflammatory and anti-oxidant property. Key words: Acetic acid, antioxidant, colitis, Psidium guajava