Evaluating the Effect of Melillotus officinalis L. Aqueous Extracts on Healing of Acetic Acid-Induced Ulcerative Colitis in Male Rats


Background: Ulcerative colitis (UC) is a form of inflammatory bowel disease (IBD) that is characterized by acute and chronic inflammation. The etiology and pathophysiology of IBD is unidentified, and there are many obstacles on the definite treatment of this disease. Recently, the useful effects of some herbal medicine on improving UC have been studied. Melillotus officinalis L. (M. officinalis) is an herb with antioxidant and anti-inflammatory effects used as food, forage and medicine.

Objectives: This study evaluated the antioxidant effects of M. officinalis aqueous extracts in the acetic acid- induced ulcerative colitis in rats.

Methods: Fifty rats were randomly divided into five equal groups. Group I (Control healthy group) received 1 mL/kg of normal saline orally. Group II (control colitis group) received 1 mL/kg of normal saline orally. Group III (positive control) received 3 mg/kg prednisolone orally. Group IV received 1000 mg/kg M. officinalis aqueous extracts orally. Group V received 2000 mg/kg M. officinalis aqueous extracts orally. Ulcerative colitis was induced by intra-rectal acetic acid (3% v/v) administration. All treatments were done 24 hours after induction of colitis and continued for seven days. On the eighth day, the rats were sacrificed and colonic biopsies were taken for histopathological and biochemical studies. Data analysis was performed, using SPSS software and significance level was set at P ≤ 0.05.

Results: Treatment with M. officinalis aqueous extract could enhance colonic antioxidant capacity and decrease inflammation and acute colonic injury induced by acetic acid, which is dose-dependent. In addition, administrating the extract significantly (P ≤ 0.05) reduced the colonic level of malondialdehyde and myeloperoxidase, and significantly (P ≤ 0.05) increased the level of reduced glutathione (P ≤ 0.05). The extract had more effects at the dose of 2000 mg/kg than 1000 mg/kg dosage and prednisolone.

Conclusions: This study revealed that M. officinalis had apparent curative effects on treating UC because of its antioxidant and anti-inflammatory activities.