Gastroprotective effect of the aqueous fraction of hydroacetonic leaf extract of Eugenia uniflora L. (Myrtaceae) (pitanga) against several gastric ulcer models in mice

摘要

Eugenia uniflora L. (Myrtaceae) is popularly known in Brazil as pitanga or ibitanga. The infusion of E. uniflora leaves is being used in folk medicine as anti-diarrheal. The present study sought to evaluate the gastroprotective potential of the aqueous fraction of hydroacetonic leaf extract of pitanga (AFHP). The leaf powder of pitanga was extracted with 50% acetone using an overhead stirrer apparatus at room temperature in which the acetone was removed under reduced pressure and the suspended aqueous. The aqueous layer was freeze-dried to yield a 122 g aqueous fraction, which was stored at -20°C. Preliminary investigation showed that AFHP (100, 300 and 1000 mg/kg, p.o.) is devoid of any behavioral neurotoxic signs. The anti-ulcer activity of AFHP was evaluated in the gastric ulcer models induced by indomethacin, stress and HCl/EtOH in mice. In order to identify possible mechanisms of gastroprotective activity of AFHP, antisecretory activity of this fraction was conducted. The quantification of adhered gastric mucus reduced glutathione (GSH) and the role of nitric oxide (NO) were also investigated. The AFHP showed antiulcer activity in various models of acutely induced ulcers. The intra-duodenal administration of this fraction reduced total acidity and increased pH of the gastric secretion. Oral administration prevented a decrease in the amount of adhered mucus and increased GSH levels. Pretreatment with L-NAME did not affect the gastroprotective effect of AFHP. Our results suggest that AFHP exhibits antiulcer activity that involved an increased in gastric mucus and in the levels of GSH.