RESUMO
Combretum duarteanum Cambess. is found in South America, particularly in Bolivia, Paraguay, and Brazil. In Paraiba state (Brazil), the species usually occurs in the Caatinga biome. It is popularly known as mofumbo, cipiúba, or cipaúba. This work aims to evaluate the gastroprotective activity and the cytoprotective mechanisms of the ethanolic extract (Cd-EtOHE) and hexane phase (Cd-HexP) obtained from the leaves of C. duarteanum. Doses at 62.5, 125, 250, and 500 mg/kg of Cd-EtOHE and Cd-HexP were tested in models of gastric ulcers induced by HCl/ethanol, absolute ethanol, stress, non-steroidal anti-inflammatory drugs, and pylorus ligation in male rats or mice. Cd-EtOHE and Cd-HexP significantly reduced gastric injuries induced in all models. Cd-EtOHE and Cd-HexP did not alter gastric juice parameters such as pH, [H(+)], or volume after pylorus ligation. Cytoprotective mechanisms of Cd-EtOHE and Cd-HexP in relation to mucus, nitric oxide (NO), and sulfhydryl (SH) groups were evaluated. Neither product increased the mucus, and they both showed dependence on NO and SH groups to prevent gastric ulcer. Both Cd-EtOHE and Cd-HexP demonstrated gastroprotective activity.
Assuntos
Antiulcerosos/farmacologia , Combretum/química , Úlcera Gástrica/prevenção & controle , Animais , Antiulcerosos/química , Antiulcerosos/isolamento & purificação , Citoproteção , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Avaliação Pré-Clínica de Medicamentos , Etanol/química , Mucosa Gástrica/efeitos dos fármacos , Mucosa Gástrica/metabolismo , Hexanos/química , Masculino , Camundongos , Muco/metabolismo , Óxido Nítrico/metabolismo , Fitoterapia , Extratos Vegetais/química , Extratos Vegetais/isolamento & purificação , Extratos Vegetais/farmacologia , Folhas de Planta , Plantas Medicinais , Ratos , Ratos Wistar , Transdução de Sinais/efeitos dos fármacos , Solventes/química , Úlcera Gástrica/etiologia , Úlcera Gástrica/metabolismo , Compostos de Sulfidrila/metabolismoRESUMO
This review of the current literature aims to study correlations between the chemical structure and gastric anti-ulcer activity of tannins. Tannins are used in medicine primarily because of their astringent properties. These properties are due to the fact that tannins react with the tissue proteins with which they come into contact. In gastric ulcers, this tannin-protein complex layer protects the stomach by promoting greater resistance to chemical and mechanical injury or irritation. Moreover, in several experimental models of gastric ulcer, tannins have been shown to present antioxidant activity, promote tissue repair, exhibit anti Helicobacter pylori effects, and they are involved in gastrointestinal tract anti-inflammatory processes. The presence of tannins explains the anti-ulcer effects of many natural products.