Antioxidant effect of dry olive (Olea europaea L.) leaf extract on ethanol-induced gastric lesions in rats

Previous studies demonstrated that the damaging action of absolute ethanol could be attributed to the enhancement in the reactive oxygen species, increase in lipid peroxidation and inhibition of antioxidative enzyme activity. In this study we investigated the mechanism of protective effect of olive leaf extract (OLE), a natural antioxidant, on gastric mucosal damage induced by absolute ethanol in rats. OLE (80 mg/kg daily) was applied intragastrically (i.g.) two weeks prior to absolute ethanol administration. Areas of gastric lesions were measured and ulcer index (UI) was calculated. The effects of applied OLE on gastric mucosal lesions, malondialdehyde level and antioxidative enzyme (catalase and superoxide dismutase) activity were compared with effects of i.g. pretreatment of reference drug, ranitidine (50 mg/kg). Absolute ethanol administration caused severe gastric mucosal haemorrhage. Pretreatment with OLE, as well as with ranitidine, significantly (p < 0.001) attenuated the gastric lesions induced. Furthermore, OLE was effective in the prevention of an increase in gastric lipid peroxidation and in the prevention of a decrease in antioxidative enzyme activity. The results obtained indicate that OLE has gastroprotective activity against ethanol-induced gastric lesions in rats, possibly related to its antioxidative properties.