RESUMEN
Quercetin is the major member of flavonoids which are phenolic compounds widely distributed in many edible plants. Several studies reported that quercetin has many beneficial effects on human health including gastroprotective and antiulcerogenic effects. This study was carried out to evaluate the potential protective effect of quercetin on experimentally induced gastric ulceration by ethanol. 42 adult male albino rats were implemented in this study and divided into 6 equal groups as follows: group I: negative control, group II: distilled water, group III: quercetin 100 mg/kg/day, group IV: 1 ml ethanol 70%, group V: quercetin for 3 days then ethanol in the same doses and group VI: ethanol followed by quercetin for 3 days in the same doses. All drugs were given to rats by gavage. The duration of the experiment was 3 days after which all animals were sacrificed and macroscopic examination of the stomach was done to determine ulcer index. Samples were collected from gastric mucosa for determination of gastric tissue levels of tumor necrosis factor alpha [TNFalpha], histamine, malondialdehyde [MDA] and total protein sulfhydryl [SH] content. Microscopic examination of the stomach was also done. Ethanol administration in group IV resulted in significant increase in the levels of TNFalpha, histamine and MDA and significant decrease in total protein SH content. Histological results revealed that ethanol induced gastric ulceration with significant increase in ulcer index. This study proved that quercetin protected against and ameliorated ethanol-induced gastric ulceration through cytokine modulation, antihistaminic and antioxidant mechanisms as shown by biochemical and histological results. This gastroprotective effect of quercetin was more significant in group V than in group VI. So, the use of quercetin can be considered in the prevention and treatment of drug induced gastric ulceration. Also, further studies are recommended to evaluate the protective effect of quercetin on other types of gastric ulcer