RESUMO
OBJECTIVES: Syngonanthus macrolepis, popularly known in Brazil as 'sempre-vivas', is a plant from the family Eriocaulaceae, it is found in the states of Minas Gerais and Bahia. The species contains a variety of constituents, including flavonoids with gastroprotective effect. In this work, a flavonoid-rich fraction (Sm-FRF) obtained from scapes of S. macrolepis was investigated for preventing gastric ulceration in mice and rats. METHODS: The activity was evaluated in models of induced gastric ulcer (absolute ethanol, stress, non-steroidal anti-inflammatory drugs and pylorus ligation). The cytoprotective mechanisms of the Sm-FRF in relation to sulfhydryl (SH) groups, nitric oxide (NO) and antioxidant enzymes were also evaluated. KEY FINDINGS: The Sm-FRF (100 mg/kg, p.o.) significantly reduced gastric injury in all models, and did not alter gastric juice parameters after pylorus ligation. CONCLUSIONS: The results indicate significant gastroprotective activity for the Sm-FRF, which probably involves the participation of both SH groups and the antioxidant system. Both are integral parts of the gastrointestinal mucosa's cytoprotective mechanisms against aggressive factors.
Assuntos
Antiulcerosos/uso terapêutico , Antioxidantes/uso terapêutico , Eriocaulaceae/química , Flavonoides/uso terapêutico , Fitoterapia , Extratos Vegetais/uso terapêutico , Úlcera Gástrica/prevenção & controle , Animais , Antiulcerosos/farmacologia , Antioxidantes/metabolismo , Antioxidantes/farmacologia , Modelos Animais de Doenças , Flavonoides/farmacologia , Suco Gástrico , Mucosa Gástrica/efeitos dos fármacos , Ligadura , Camundongos , Camundongos Endogâmicos , Óxido Nítrico/metabolismo , Extratos Vegetais/farmacologia , Ratos , Ratos Wistar , Úlcera Gástrica/etiologia , Úlcera Gástrica/metabolismo , Compostos de Sulfidrila/metabolismoRESUMO
Flavonoid-rich Praxelis clematidea (Griseb.) R.M.King & H.Robinson (Asteraceae) is a native plant of South America. This study evaluates the gastroprotective activity and possible mechanisms for both the chloroform (CHCl3P) and ethyl acetate phases (AcOEtP) obtained from aerial parts of the plant. The activity was investigated using acute models of gastric ulcer. Gastric secretion biochemical parameters were determined after pylorus ligature. The participation of cytoprotective factors such as mucus, nitric oxide (NO), sulfhydryl (SH) groups, prostaglandin E2 (PGE2), reduced glutathione (GSH), superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GR), reduction of lipid peroxidation (malondialdehyde level), and polymorphonuclear infiltration (myeloperoxidase activity), was also investigated. CHCl3P (125, 250, and 500 mg/kg) and AcOEtP (62.5, 125, and 250 mg/kg) showed significant gastroprotective activity, reducing the ulcerative index by 75, 83, 88% and 66, 66, 81% for ethanol; 67, 67, 56% and 56, 53, 58% for a non-steroidal anti-inflammatory drug (NSAID); and 74, 58, 59% and 64, 65, 61% for stress-induced gastric ulcer, respectively. CHCl3P (125 mg/kg) and AcOEtP (62.5 mg/kg) significantly reduced the ulcerative area by 78 and 83%, respectively, for the ischemia-reperfusion model. They also did not alter the biochemical parameters of gastric secretion, the GSH level or the activities of SOD, GPx or GR. They increased the quantity of gastric mucus, not dependent on NO, yet dependent on SH groups, and maintained PGE2 levels. The P. clematidea phases demonstrated gastroprotective activity related to cytoprotective factors.