Ethnopharmacological relevance: Ulcerative colitis (UC) which has a global impact on the health care system with its recurrent and incompletely curable characteristics, affects the patients' quality of life. Gilaburu (GB; Viburnum opulus L.) is a fruit with rich polyphenol ingredient which is used ethnobotanically in Türkiye for medicinal purposes (for example, to pass kidney stones, to treat stomach, heart, and liver diseases, hemorrhages, hypertension, ulcers, common cold, tuberculosis, rheumatic and menstrual pain, and diabetes). On the other hand, the effects of GB in the experimental UC model have not been studied.
Aim of the study: This study aimed to explore the potential antioxidant and anti-inflammatory effects of GB fruit extract in improving acetic acid (AA)-induced UC.
Materials and methods: Starting immediately after (AA + GB group) or 1 week before (GB + AA + GB group) the colitis induced by intrarectal AA (5%; v/v) administration, the rats orally received GB (100 mg/kg) once per day for 3 days. The control and AA groups were administered orally saline (1 ml), while the AA + SS group were administered sulfasalazine (SS; 100 mg/kg; orally) as a positive control once per day for 3 days. Distal colonic tissue specimens were obtained for the histological and biochemical [myeloperoxidase (MPO), malondialdehyde (MDA), glutathione (GSH), chemiluminescence (CL), caspase-3, 8-hydroxy-2'-deoxyguanosine (8-OHdG), matrix metalloproteinase (MMP)-9, transforming growth factor (TGF)-β1, smad-3 and cytokine (tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, IL-8, interferon (IFN)-γ), measurements] evaluations on the 3rd day.
Results: Elevated macroscopic and microscopic damage scores, high tissue wet weight values, increased tissue-associated MPO, MDA, CL, caspase-3, 8-OHdG, cytokines (TNF-α, IL-1β, IL-6, IL-8), MMP-9, TGF-β1, smad-3 levels, and decreased GSH values of the AA group were all reversed by GB treatments (AA + GB and GB + AA + GB groups) (p < 0.05-0.001). However, sulfasalazine treatment (AA + SS group) did not change the IL-8, 8-OHdG, MMP-9, and TGF-β1 measurements significantly.
Conclusions: Gilaburu shows both anti-inflammatory and antioxidant effects against AA-induced colonic damage by suppressing neutrophil infiltration, regulating inflammatory mediators, inhibiting reactive species production, lipid peroxidation, and apoptosis, conserving endogenous antioxidant glutathione, and ameliorating oxidative DNA damage. Since the current ulcerative colitis drugs display limited benefits and adverse side effects, potential therapeutic and/or prophylactic role of gilaburu can be evaluated in ulcerative colitis.
Keywords: Acetic acid; Oxidative damage; Polyphenols; Sulfasalazine; Ulcerative colitis; Viburnum opulus L.
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