Protective effect of quercetin [QRT], a bioflavonoid on stress-induced gastric ulcers in rats

Peptic ulcer is one of the most common diseases which represent a serious medical problem due to its frequency, high economic cost and frequent adverse reactions associated with drugs used in its management. In this work, an attempt was undertaken to investigate the protective effect of quercetin [QRT], the most abundant natural bioflavonoid which is widely distributed in edible plants and has a powerful antioxidant effect on stress-induced gastric ulcers in rats. In this experimental model the pathogenesis of the lesions has been related to the production of reactive oxygen species. The rats were randomly classified into 4 equal groups, [10 animals each] as follows: [1] Control group, [2] Pylorically ligated group in which animals were subjected to pyloric ligation only, [3] Cold restraint stress [CRS] group in which rats were subjected to pyloric ligation, allowed to recover, and then restrained by immobilizaiton and placed in a refrigerator at 4°C for 3 hours, and [4] Quercetin [QRT] treated group that received 50 mg/kg QRT intraperitonealy 1 hour before pyloric ligation and induction of gastric mucosal ulceration by cold restraint stress. Three hours later, all rats were decapitated, their stomachs were removed and the gastric content of groups 2, 3 and 4 were collected. Then, gastric juice parameters [volume, total acidity, total acid output, total pepsin concentration as well as glycoprotein contents] were studied. Also, the effect of QRT on stress induced gastric ulcer parameters [ulcer incidence; ulcer score; ulcer index and preventive index] were investigated in groups 1, 3 and 4. On the other hand, prior to decapitation, blood samples were collected from all animals for measurement of superoxide dismutase [SOD] activity in red blood cell [RBC] lysates as an index of the antioxidant state. The results obtained in the present study clearly demonstrate that intraperitioneal administration of QRT led to a markedly significant reduction in the occurrence of gastric ulceration in all treated rats as evidenced by the reduction of the mean ulcer score and ulcer index with a preventive index of 73.5%. Pretreatment with QRT was also associated with a significant decrease in the total acid and pepsin concentrations as well as a highly significant increase of glycoprotein contents compared with cold restraint group. Furthermore, the administration of QRT significantly increased SOD level as compared to cold restraint group. It is concluded that QRT has a protective effective role against stress-induced gastric ulcer in rats and the relevance of these results was discussed