Introduction: Many drugs with high efficacy are used to treat stomach ulcers, but they have many side effects. Therefore, much effort has been made to find new effective compounds from plant extracts. The aqueous extract of the internal layer of oak fruit (jaft) contains antioxidants and tannins; it has many desirable properties such as inhibition of the growth of pathogens. In this study, the preventing effect of Jaft extract on stomach ulcers induced by stress was investigated.

Matherials and Methods: The effect of the extract on the prevention of gastric ulcer was investigated using a variety of methods including pH measurement, nitric oxide (NO), malondialdehyde (MDA), and histological methods. Rats were randomly divided into six groups. Five groups were gavage fed with different concentrations of Jaft extract, ranitidine and normal saline. The sixth group was gavage fed with normal saline as the control group. Ranitidine and normal saline were used as positive and negative controls, respectively. Data were analyzed by one-way analysis of variance (ANOVA) followed by Tukey’s post hoc test using SPSS version 18.0.

Results: It was revealed that the average thickness of the mucous glands and mucosal folds in the groups receiving the extract (250, 500 and 750 mg/kg) did not significantly decrease when compared with the situation of the control group (p<0.05). However, the average nitric oxide (NO) and malondialdehyde (MDA) in the control group meaningfully decreased in comparison with groups receiving the extract (250, 500 and 750 mg/kg). The average pH in groups receiving the extract and ranitidine significantly increased compared to the control group (p<0.05).

Conclusions: Jaft extract contains abundant polyphenolic compounds and tannins and has several biological properties such as pharmacological properties, antioxidant activity, and inhibition of lipid oxidation. Therefore, it has the potential to prevent and treat stomach ulcers.