Intestinal anti-inflammatory effect of the rhizome extracts of Menispermum dauricum DC. on trinitrobenzene sulfonic acid induced ulcerative colitis in mice

Abstract

Ethnopharmacological relevanceMenispermum dauricum DC., commonly known as “Bei Dou Gen” (BDG) in China, has been used extensively in folk medicine to treat inflammatory diseases, especially intestinal inflammations such as enteritis and dysentery, and in pharyngitis, tonsillitis, rheumatism and bronchitis. Although previous studies showed that BDG has anti-inflammatory activities, its effects on ulcerative colitis (UC) have not yet been explored. Aim of the studyTo investigate the intestinal anti-inflammatory effect of the rhizome extracts of Menispermum dauricum DC. on UC model induced by 2,4,6-trinitrobenzene sulfonic acid (TNBS) in mice. Materials and methodsUC in mice was induced by colonic administration with TNBS. BDG (100, 200 and 400mg/kg/day) and sulfasalazine (500mg/kg/day) were administered orally for 7 consecutive days. The inflammatory degree was assessed by gross appearance, macroscopic and histological analysis, and accumulation of myeloperoxidase (MPO) activity. Pro-inflammatory mediators, including tumor necrosis factor (TNF)-α, interleukin (IL)-1β and IL-6, were determined by enzyme-linked immunoassay. The expression of cyclooxygenase (COX)-2 was assessed by immunohistochemical analysis. ResultsTreatment with different doses of BDG significantly ameliorated macroscopic damage and histological changes, reduced the accumulation of MPO activity, depressed serum and colonic tissue levels of TNF-α, IL-1β and IL-6 in a dose-dependent manner. In addition, administration of BDG effectively reduced COX-2 overexpression in colon. ConclusionWe demonstrated for the first time that BDG possessed marked intestinal anti-inflammatory effect in TNBS induced colitis in mice, which might be related to the reduction of up-regulated productions and expressions of pro-inflammatory mediators, suggesting that it may have beneficial use for the treatment of inflammatory bowel disease.