Maytenus robusta Reissek, a medicinal plant popularly used to treat digestive diseases, promotes ameliorative effects in colon and liver of mice exposed to dextran sulfate sodium

Ethnopharmacological relevance: Maytenus robusta Reissek (Celesteraceae), popularly named as cafezinho do mato or coração de bugre, is employed to treat inflammatory digestive diseases in the south of Brazil. However, despite popular usage, the effects of this species on an experimental model of ulcerative colitis are unknown.

Aim of the study: To evaluate the effects of M. robusta extract (HEMR) on colon and liver from mice with colitis induced by dextran sulfate sodium (DSS).

Materials and methods: Firstly, the cytotoxicity of HEMR and its effects on ROS and nitrite production in IEC-6 cells were evaluated. The experimental colitis was established by adding 3% DSS on drinking water of mice and the effects of HEMR (1 - 100 mg/kg, p.o, once a day by 7 days) in colonic and hepatic tissues were analyzed.

Results: The HEMR (1-100 μg/mL) did not alter the cell viability but reduced nitrite production of IEC-6 stimulated by LPS. Moreover, HEMR (100 mg/Kg) attenuates macro and microscopic alterations in the colon from mice exposed to DSS, as evidenced by a reduction of the colon shortening, attenuation of the epithelial erosion, submucosal edema and preservation of the Goblet cells integrity, as well as the restoration of mucin depletion. The treatment with HEMR increased GSH amount, reduced LOOH levels and normalizes CAT activity in the colon. The group treated with HEMR showed increased GST activity, reduced MPO activity and decreased inflammatory cytokines secretion (TNF and IL-6) in the colonic tissue. In the liver, HEMR increased GST activity, decreased the GPx activity and reduced IL-6 levels. Furthermore, the HEMR treatment reduced AST and ALT serum levels in mice exposed to DSS. Finally, the HEMR was able to reduce intestinal transit.

Conclusions: HEMR treatment minimizes inflammation of the colon and maintaining the antioxidant homeostasis. In addition, HEMR may be a potential tool to prevent hepatic injury secondary to ulcerative colitis.

Keywords: IEC-6 cells; inflammatory bowel diseases; liver damage; oxidative stress.