Silymarin, an antioxidant bioflavonoid, inhibits experimentally-induced peptic ulcers in rats by dual mechanisms

INTRODUCTION: Antioxidants are reported to have antiulcer activity. We investigated silymarin, a bioflavonoid antioxidant, for antiulcer potential. MATERIALS AND METHODS: Pylorus-ligated Shay rats (n=5) were used as the experimental gastric ulcer animal model. The rats, separated into three groups, were administrated silymarin (50 mg/kg), omeprazole (3.6 mg/kg), or saline (5 ml/kg) per orally daily for 5 days prior to ulcerogenic challenge. Nineteen hours after the challenge, the rats were sacrificed and their stomachs isolated. Formed gastric juice was collected for measurement of volume, titrimetric estimation of free and total acidity, and total acid output by the conventional methods. The ulcer index was calculated. Total acid output and free and combined acid quantities were calculated using the acidity value and the volume of formed gastric juice. RESULTS: Silymarin exerted significant (P<.05) antiulcer activity (the ulcer index was reduced to 7.4 ± 1.0 from the control value of 19.8 ± 4.1). Silymarin also significantly reduced free and total acidity, gastric juice volume, total acid output, and combined acid content. The results were analyzed by ANOVA and Newman–Keuls multiple comparison test. CONCLUSION: This study demonstrates that silymarin has significant antiulcer activity. It perhaps acts by decreasing hydrochloric acid output and increasing buffering power (combined acid).