Effect of Brazilian green propolis on experimental gastric ulcers in rats.

Propolis is a resinous hive product collected by honeybees from plants. The propolis produced in Southeastern of Brazil is known as green propolis because of its color. Modern herbalists recommend its use because it displays antibacterial, antifungal, antiviral, hepatoprotective, anti-inflammatory, immunomodulatory and anti-ulcer properties. The anti-ulcer activity of green propolis hydroalcoholic crude extract was evaluated by using models of acute gastric lesions induced by ethanol, indomethacin and stress in rats. Moreover, the effects of extract on gastric content volume, pH and total acidity, using pylorus ligated model were evaluated. Animals pretreated with propolis hydroalcoholic crude extract (50, 250 and 500 mg/kg) showed a significant reduction in lesion index, total affected area and percentage of lesion in comparison with control group (p<0.05) in the ethanol-induced ulcer model. Green propolis extract, at a higher dose (500 mg/kg), displayed a significant protection by reducing (p<0.05) the evaluated parameters in the gastric ulceration induced by indomethacin. In the stress-induced ulcer model it was observed a significant reduction (p<0.05) in those parameters in animals treated with green propolis extract (250 and 500 mg/kg). Regarding the pylorus ligated model it was observed that green propolis extract (250 and 500 mg/kg) displayed an anti-secretory activity, which lead to a reduction in the gastric juice volume, total acidity and pH. These findings indicate that Brazilian green propolis displays good anti-ulcer activity, corroborating the folk use of propolis preparations, and contributing for its pharmacological validation.