Effects of silymarin on the acute stage of the trinitrobenzenesulphonic acid model of rat colitis.

The intestinal anti-inflammatory activity of several doses of silymarin was tested in the acute stage of the trinitrobenzenesulfonic acid (TNBS) model of rat colitis. The results obtained show that oral pre-treatment with 50 mg/kg of silymarin significantly attenuated macroscopic colonic damage as well as reduced colonic myeloperoxidase activity compared to non-treated colitic animals. The beneficial effect was accompanied by an improvement in the colonic oxidative status, which was altered in colonic inflammation, by preventing glutathione depletion and reducing malonyldialdehyde production. This suggests that the well known antioxidant properties of silymarin can participate in its intestinal anti-inflammatory activity. In addition, a preservation in the colonic absorptive function was also observed, and this effect can also account for the colonic protective effect observed in this model of acute colitis.