Effect of flavonoid quercetin on stress-induced gastric ulcer in rats

Introduction: Mental stress is one of the most important causes of the gastric ulcer. On the other hand, flavonoids such as quercetin show protective effects. The aim of this study was to investigate possible protective effect of quercetin on water restraint stress-induced ulcer in rats. Methods: Adult male Wistar rats were divided into seven groups each containing eight animals. The first group (S) received normal saline (5 ml/kg, p.o.) and groups 2-7 received normal saline, quercetin 25, 50, 100, 200 (mg/kg, p.o.) or omeprazole (20 mg/kg, s.c.) respectively. After 1 hour, all animals except the first group (S) were placed into the plexiglass restrainers and kept in water (23°C) for 3.5 hours. After another 3.5 hours interval, rats were scarified and volume of gastric output, pH, acid content and ulcer index (UI) were measured. Results: pH of gastric content in QS50-QS200 groups was lower than the saline/stress (SS) treated group (P<0.05). The gastric acid content in the saline treated group was higher than SS, quercetin/stress (QS) 50 and QS 200 groups (P<0.05) and higher than omeprazole/saline (OS) group. Omeprazole inhibited the gastric acid secretion. The UI in the QS25 and QS50 groups were lower than of SS group (P<0.05 and P<0.01 respectively) The UI in the QS100 and QS200 groups were identical to SS group. The UI in S and OS groups was approximately zero. Conclusion: The results of this study suggest the protective effect of quercetin in stress-induced gastric ulcer test. However this protective effect is not precisely dose independent.