Oleuropein prevents ethanol-induced gastric ulcers via elevation of antioxidant enzyme activities in rats

Abstract

Purified oleuropein from olive leaf extract has been shown to have antioxidant effects in our recent studies. Thus, the aim of this study was to assess the antioxidant abilities of oleuropein in comparison with ranitidine in ethanol-induced gastric damages via evaluation of ulcer index inhibition, antioxidant enzyme activities, and lipid peroxidation level. Fifty-six adult male Sprague-Dawley rats were divided into seven equal groups as follows: control group, ethanol group (absolute ethanol 1 ml/rat), oleuropein group (12 mg/kg), and oleuropein (6, 12, and 18 mg/kg) plus ethanol groups, as well as ranitidine (50 mg/kg) plus ethanol group. Pretreatment with oleuropein (12 and 18 mg/kg) significantly increased the ulcer index inhibition (percent), in comparison with oleuropein (6 mg/kg). Glutathione peroxidase (GPx) activity was significantly lower in the ethanol group when compared with the other groups whereas, treatment of rats with oleuropein (12 mg/kg) significantly increased glutathione content in gastric tissue when compared with the other groups, and lipid peroxidation was significantly reduced in the oleuropein- (12 and 18 mg/kg) and ranitidine-treated animals. Superoxide dismutase (SOD) and catalase (CAT) activities were both much higher in oleuropein-treated rats than the ethanol group, and although there was a moderate increase in SOD and CAT activities in ranitidine-treated rats, the differences were not significant. These findings suggest that oleuropein has beneficial antioxidant properties against ethanol-induced gastric damages in the rat. Therefore, it seems that a combination regimen including both antioxidant and antisecretory drugs may be beneficial in prevention of ethanol-mediated gastric mucosal damages.

The Effects of Moderate Exercise on Ethanol-Induced Gastric Injuries in Rats

“…malondialdehyde) [28]. In a previous study we demonstrated that substances with antioxidant properties may protect gastric mucosa against ethanol damaging effects [20]. Therefore, these results are in agreement with the previous report.…”

“…The present study also showed that the exercise reduced the ethanol induced gastric erosion and submucosal edema. It is wellknown that ethanol acts as a damaging agent to gastric mucosa and has been widely used for the experimental evaluation of anti-ulcer activities of different chemicals [5,8,20]. It has been suggested that ethanol induced gastric mucosal lesions may be attributed to the mechanisms such as: (1) increased oxygen-derived free radicals, (2) decreased concentration of reduced glutathione contents in gastric mucosa, (3) direct damage to the mucin layer or mucin synthesis and (4) gastric cell's apoptosis [8,24].…”

“…GPx and CAT can decompose H 2 O 2 to water. Although H 2 O 2 is not a particularly reactive product, it may be reduced to the highly reactive metabolites hydroxyl radicals and/or single oxygen [20,27].…”

“…At the end of exercise period, the rats were fasted and allowed access to water ad libitum for 24 hours before ethanol ingestion. Animals in groups A and B received orally (1 mL/rat) normal saline while groups C and D received absolute ethanol (1 mL/rat) by gavage to induce gastric ulceration [20]. One hour after saline and ethanol administration, all of animals were sacrificed upon light ether anesthesia (Dagenham, UK) by decapitation, and the stomachs were removed, inflated by injecting 2 mL of normal saline and opened along the greater curvature.…”

Novel Antioxidant Properties of Ghrelin and Oleuropein Versus Lipopolysaccharide-Mediated Renal Failure in Rats

“…For this purpose, we used oleuropein a phenolic compound in olive leave extract, as an antioxidant agent based on our previous reports (Alirezaei et al , 2012a(Alirezaei et al , b, 2014, to investigate beneficial effects of the hormone. In this regard, it has been shown that oleuropein is rapidly absorbed from the intestine with t max of 2 h reaching a peak of 200 ng/ml of plasma after administration of 15-20 mg/kg oleuropein in rats (Alirezaei et al 2012b).…”