Increased pro-inflammatory cytokines and oxidative stress contribute to the pathophysiology of ulcerative colitis (UC). Inula viscosa is a plant with antioxidant and anti-inflammatory properties. We investigated the effect of an ethanolic extract of I. viscosa on an experimental UC model created using acetic acid. Rats were divided into four groups of eight: group 1, control; group 2, 3% acetic acid group; group 3, 100 mg/kg sulfasalazine + 3% acetic acid group; group 4, 400 mg/kg I. viscosa + 3% acetic acid. I. viscosa and sulfasalazine were administered by oral gavage and 3% acetic acid was administered per rectum. We found that I. viscosa treatment decreased colon malondialdehyde, tumor necrosis factor-α, interleukin-1 beta and nuclear factor kappa B levels; it increased reduced glutathione, nuclear factor erythroid 2-related factor 2, heme oxygenase-1 and kelch-like ECH-associated protein 1 levels and glutathione peroxidase enzyme activity. Group 1 colon exhibited normal histological structure. Slight inflammatory cell infiltration and edema and insignificant slight erosion in crypts were detected in colon tissues of group 4. We found that I. viscosa reduced oxidative stress and inflammation, which was protective against UC by inducing the Nrf-2/Keap-1/HO-1 pathway in the colon.
Keywords: Acetic acid; Inula viscosa; antioxidant; inflammation; rats; ulcerative colitis.