The protective effect of epicatechin on experimental ulcerative colitis in mice is mediated by increasing antioxidation and by the inhibition of NF-κB pathway

Abstract

Background: Ulcerative colitis (UC) is a chronic inflammatory intestinal disease. It is necessary to find out new effective drugs for UC. In our study epicatechin extracted from grape seed by our institute for the first time could treat UC effectively. Then anti-UC mechanisms of epicatechin were elucidated in vivo and in vitro.

Methods: Dextran sulfate sodium (DSS)-induced acute UC mice model was used to evaluate the activity of epicatechin and its properties against UC. Then its anti-inflammatory and antioxidant effects were evaluated as follows: the concentrations of TNF-α and IL-6 in the colon supernatants were determined by ELISA. NO and MPO were assayed by Griess method and commercial kit respectively. NF-κB were determined by NF-κB-Dependent Reporter Gene Expression Assay and Western Blotting respectively. Antioxidant factors such as SOD, MDA, GSH-Px and CAT were also measured in colon tissues and cell supernatant stimulated by LPS respectively.

Results: In C57BL/6J mice model with DSS-induced UC, epicatechin was able to decrease the disease activity index and colon macroscopic damage index scores, reduce body weight loss, and significantly relieve colon contracture and crypt damage. TNF-α, IL-6, NO, MPO and MDA were reduced in the mice administered epicatechin, whereas antioxidant enzymes showed increased activity in epicatechin-treated mice and cell line respectively. Furthermore, inhibition effect on NF-κB activation by epicatechin were demonstrated in vivo and in vitro.

Conclusions: Epicatechin has inhibitory effect on DSS-induced acute UC. This effect is mainly due to its antioxidant effect and the inhibition of inflammatory molecules related to NF-κB pathway.

Keywords: Antioxidation; Inflammation; NF-κB; Ulcerative colitis.