Investigation of protective effect of olive leaf (Olea Europaea) extract on indomethacin-induced gastric damage in rats

Objective: To investigate the protective effects of olive leaf (Olea Europaea) extract in gastric ulcer induced by indomethacin. Materials and Methods: In the study, 42 male Sprague Dawley rats were used. Olive leaves (Olea Europaea) were collected under appropriate conditions, crushed with liquid nitrogen, dissolved in ethanol and concentrated olive leaf extract was obtained by evaporation. Rats were divided into seven groups as control group, ulcer group (25 mg/kg indomethacin), olive leaf extract (400 mg/kg) group, ulcer group receiving lansoprazole (30 mg/kg) (reference drug), ulcer group receiving olive leaf extract (100, 200, 400 mg/kg) (n=6). After the animals were fasted for 16 hours, all substances were administered orally at the indicated doses and amounts. After 15 minutes, indomethacin (25 mg/kg öşe) was administered to all rats except control and 400 mg olive leaf groups. After 6 hours, the rats were euthanised under anaesthesia by taking 5 ml of blood from their hearts and their stomachs were removed. The tissues were histopathologically examined using haematoxylin-eosin staining technique and interleukin 1 beta (IL-1β) and TNF alpha (TNF-α) levels were determined by ELISA method using a commercial kit, Malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), glutathione (GSH), myeloperoxidase (MPO) and glutathione peroxidase (GPx) levels were determined by spectrophotometric manual method. Kruskal-Wallis H test was used for statistical analysis of biochemical data. Evaluation of histopathological findings was performed by one-way ANOVA and Tukey test. Results: As a result of macroscopic examinations, no gastric damage was observed in the control group and in the group given 400 mg olive leaf extract. The rates of damage caused by olive leaf extract (100 mg/kg- 200 mg/kg- 400 mg/kg) given together with indomethacin in the rat stomach were 0.89%, 0.67% and 0.83%, respectively. As a result of biochemical analyses, a significant difference was found between GSH, KAT, MDA, MPO, SOD and GPx values of indomethacin group, lansoprazole + indomethacin group and olive leaf extract groups and control group (p<0.05). There was a significant decrease in TNF-α and IL-1β levels in the groups treated with olive leaf extract (H=40.216, p=0.00). When all parameters were evaluated together, it was determined that 200 and 400 mg/kg doses were generally protective and the most effective öşe was 400 mg/kg olive leaf extract. No toxic effect was observed in the 400 mg olive leaf extract group in which the highest öşe was applied. Conclusion: Our findings indicate that olive leaf extract is protective against gastric ulcer and oxidative stress induced by indomethacin