RESUMO
Ethanol is a psychoactive substance highly consumed around the world whose health problems include gastric lesions. Baccharis trimera is used in folk medicine for the treatment of gastrointestinal disorders. However, few studies have evaluated its biological and toxic effects. To validate the popular use of B. trimera and elucidate its possible antiulcerogenic and cytotoxic mechanisms, a hydroethanolic extract of B. trimera (HEBT) was evaluated in models of gastric lesions. Rats and mice were used to evaluate the protective and antiulcerogenic effects of HEBT on gastric lesions induced by ethanol, acetic acid, and chronic ethanol consumption. The effects of HEBT were also evaluated in a pylorus ligature model and on gastrointestinal motility. The LD50 of HEBT in mice was additionally estimated. HEBT was analyzed by nuclear magnetic resonance, and a high-performance liquid chromatography fingerprint analysis was performed. Oral HEBT administration significantly reduced the lesion area and the oxidative stress induced by acute and chronic ethanol consumption. However, HEBT did not protect against gastric wall mucus depletion and did not alter gastric secretory volume, pH, or total acidity in the pylorus ligature model. Histologically, HEBT accelerated the healing of chronic gastric ulcers in rats, reflected by contractions of the ulcer base. Flavonoids and caffeoylquinic acids were detected in HEBT, which likely contributed to the therapeutic efficacy of HEBT, preventing or reversing ethanol- and acetic acid-induced ulcers, respectively. HEBT antiulcerogenic activity may be partially attributable to the inhibition of free radical generation and subsequent prevention of lipid peroxidation. Our results indicate that HEBT has both gastroprotective and curative activity in animal models, with no toxicity.
Assuntos
Ácido Acético , Antiulcerosos/farmacologia , Baccharis , Etanol/química , Extratos Vegetais/farmacologia , Solventes/química , Úlcera Gástrica/prevenção & controle , Estômago/efeitos dos fármacos , Animais , Antiulcerosos/isolamento & purificação , Antiulcerosos/toxicidade , Antioxidantes/farmacologia , Baccharis/química , Citoproteção , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Feminino , Esvaziamento Gástrico/efeitos dos fármacos , Mucosa Gástrica/metabolismo , Motilidade Gastrointestinal/efeitos dos fármacos , Dose Letal Mediana , Peroxidação de Lipídeos/efeitos dos fármacos , Masculino , Camundongos , Estresse Oxidativo/efeitos dos fármacos , Fitoterapia , Extratos Vegetais/isolamento & purificação , Extratos Vegetais/toxicidade , Plantas Medicinais , Ratos Wistar , Estômago/patologia , Estômago/fisiopatologia , Úlcera Gástrica/induzido quimicamente , Úlcera Gástrica/metabolismo , Úlcera Gástrica/patologiaRESUMO
Green tea is an infusion of unfermented leaves of Camellia sinensis (L.) Kuntze (Theaceae), traditionally used for the treatment of obesity, hypercholesterolemia, and gastric complaints. This study evaluated the mechanisms involved in the gastric ulcer healing of the hydroalcoholic extract from green tea (GEt), its ethyl acetate fraction, (GEAc) and epigallocatechin gallate (EGCG) using the model of acetic acid-induced gastric ulcer in rats. The chronic gastric ulcer was induced by application of 80 % acetic acid on serosal mucosa of rats. After 7 days of oral treatment with GEt and GEAc, the ulcer area, mucin content, inflammatory parameters (MPO and NAG), and antioxidant system (GSH and LOOH levels, SOD and GST activities) were evaluated. In vitro, the scavenging activity of GEt and GEAc were also measured. The antisecretory action was studied on the pylorus ligature method in rats. Oral treatment with GEt and GEAc reduced significantly the gastric ulcer area induced by acetic acid. The gastric ulcer healing was accompanied by increasing of mucin content, restoration of GSH levels and SOD activity, and reduction of MPO and LOOH levels. In addition, GEt and GEAc reduced the DPPH free radicals in vitro. Furthermore, the oral treatment of animals with GEt and GEAc did not alter the gastric acid secretion or cause signs of toxicity. Collectively, these results showed that GEt had a pronounced antiulcer effect, possibly through maintenance of mucin content and reduction of inflammation and oxidative stress. In addition, the compounds present in its ethyl acetate fraction could be responsible for the extract activity.