(-)-Fenchone Ameliorates TNBS-Induced Colitis in Rats via Antioxidant, Immunomodulatory, and Cytoprotective Mechanisms

Background: (-)-Fenchone is a bicyclic monoterpene present in the plant species Foeniculum vulgare Mill, Thuja occidentalis L. (tuja), and Lavandula stoechas (lavender). These plants have therapeutic value in the treatment of intestinal disorders. Aim: To evaluate intestinal anti-inflammatory activity in an acute and chronic trinitrobenzene sulphonic acid (TNBS)-induced colitis model in rats. Methods: Intestinal anti-inflammatory effects were assessed using the acute and chronic TNBS-induced colitis model in rats. The mechanisms were evaluated from colonic tissue fragments of the acute and chronic models. Results: Oral administration of the (-)-fenchone (37.5–300 mg/kg) acute phase or (150 mg/kg) (p < 0.001) chronic phase reduced the macroscopic lesion score, ulcerative area, intestinal weight/length ratio, and diarrheal index in TNBS-treated animals. At a dose of 150 mg/kg, the acute and chronic phase decreased malondialdehyde (MDA) and myeloperoxidase (MPO) (p < 0.001), restored glutathione (GSH) levels and superoxide dismutase (SOD) (p < 0.001), decreased immunomarking for factor nuclear kappa B (NF-κB) and levels of interleukin (IL)-1 and tumor necrosis factor α (TNF-α), and maintained IL-10 and TGF-β basal levels. Furthermore, increased immunostaining for zonula occludens 1 (ZO-1) was observed. Conclusions: (-)-fenchone has intestinal anti-inflammatory activity related to cytoprotection of the intestinal barrier, as well as antioxidant and immunomodulatory effects.