The healing effect of licorice extract in acetic acid-induced ulcerative colitis in rat model

Several studies have shown the antioxidant and anti-inflammatory effects of licorice extract. This study aims to evaluate the anti-inflammatory and healing effects of licorice extract in acetic acid-induced ulcerative colitis (UC) in rat as an animal model. In summer 2008, forty-eight male Wistar rats were divided into six equal groups. Group I as normal control group received 0.5 ml/kg normal saline; group II, 0.5 ml/kg saline after induction of UC with 3% acetic acid; group III, 50 mg/kg licorice extract orally; group IV, 100 mg/kg licorice extract orally; group V, 150 mg/kg licorice extract orally; and group VI, 150 mg/kg licorice extract intracolonic. In all animals, the distal 10-cm portion of the colon was removed after 7 days for macroscopic and histological investigation. Inflammation following acetic acid administration was characterized by edema, diffuse inflammatory cell infiltration, and necrosis. Administration of oral 100 and 150 mg/kg and intracolonic 150 mg/kg of licorice extract significantly reduced the colonic inflammatory response and edema. Intracolonic administration of licorice extract showed more anti-inflammatory and healing effects in comparison to other groups. Therefore, licorice extract can be suggested as a therapeutic of choice in UC.