Evaluating Anti-Inflammatory Effect of Hydroalcoholic Extracts of Citrus medica L. Pulp and Peel on Rat Model of Acute Colitis

Background and objectives: Citrus medica L. (citron) belongs to the Rutaceae family and contains several bioactive compounds including flavonoids, alkaloids, coumarins and essential oils with great antioxidant and anti-inflammatory properties. Since alleviating inflammation and ulcers have been suggested for these bio-compounds, this study was conducted in a model of experimental colitis. Methods: In order to standardize the extracts prepared by the maceration, total flavonoids were assayed. Colitis was induced by acetic acid in male Wistar rats. Rats received three doses (150, 300, and 600 mg/kg) of the citron’s peel and pulp hydroalcoholic extracts for five days. Dexamethasone (1mg/kg) and sulfasalazine (150 mg/kg) were administered as reference medications. The macroscopic parameters including weight of colon, ulcerated area, the severity and indices of ulcers, as well as tissue microscopic features were assessed. In addition, levels of myeloperoxidase (MPO) activity and malondialdehyde (MDA) were measured. Results: Total flavonoid contents for peel and pulp extracts were obtained 6.25 and 37.5 mg/g equivalent to quercetin, respectively. Both citron extracts demonstrated great anti-inflammatory and antioxidant effects by decreasing MDA and MPO levels comparable to the reference drugs. Administration of the citron extracts also significantly reduced colon weight as well as ulcer index, score, and area compared to the control group. In addition, pathologic parameters such as inflammation, cryptal damage and leucocyte infiltration were considerably decreased in rats received citron extracts. Conclusions: Both citron extracts showed anti-inflammatory effects on experimental acute colitis. Further investigations are required to suggest these extracts for colitis treatment in clinical setting.