Evaluation of the Protective Effect of Hydroalcoholic and Aqueous Extracts of Ulmus minor Leaves on Ulcerative Colitis Induced by Acetic Acid in Rats

Background: Ulcerative colitis (UC) is a chronic inflammatory disease of the large intestine that cannot be cured, but its symptoms can be managed. Objectives: This study aimed to evaluate the protective effects of hydroalcoholic and aqueous extracts of Ulmus minor leaves on UC induced by acetic acid in rats. Methods: Rats were randomly divided into seven groups of five, and 3% acetic acid was used to induce colitis. To assess the protective effect of Ulmus minor leaves, macroscopic, microscopic, and histological evaluations were performed on the different study groups. Results: Macroscopic examinations of both the hydroalcoholic and aqueous extract groups showed that the aqueous extract at a dose of 200 mg/kg provided the best protective effect on colon tissue. Rats treated with hydroalcoholic extracts at doses of 100 mg/kg and 200 mg/kg, as well as those treated with aqueous extract at 100 mg/kg, also showed favorable outcomes compared to the control group, with a significant difference (P < 0.05). Furthermore, among the groups treated with hydroalcoholic and aqueous extracts, the aqueous extract at 200 mg/kg demonstrated the most protective effects based on microscopic and histological evaluations of the colon. Conclusions: The extracts of Ulmus minor leaves demonstrated anti-inflammatory properties in an animal model of colitis. Further studies are required to evaluate their potential therapeutic benefits in patients with UC.