Al-Quraishy S.Othman M.S.Dkhil M.A.Abdel Moneim A.E.Department of ZoologyCollege of ScienceKing Saud UniversityRiyadhSaudi Arabia; Faculty of Preparatory YearUniversity of HailHailSaudi Arabia; Faculty of BiotechnologyOctober University for Modern Science and Arts (MSA)GizaEgypt; Department of Zoology and EntomologyFaculty of ScienceHelwan UniversityCairoEgypt2020-01-092020-01-0920177533322https://doi.org/10.1016/j.biopha.2017.04.069PubMedID28463797https://t.ly/YXe0vScopusGastritis is preponderantly characterized by inflammation of the lining epithelial layer and the chronic gastritis is considered as a pre-cancer lesion. For many centuries olive (Olea europaea) leaf has been used for its putative health potential, nonetheless, to date, the gastroprotective effects of olive leaves have not been studied yet. Hence, in this study we investigated whether olive leaf extract (OLE) could protect gastric mucosa against HCl/ethanol-induced gastric mucosal damage in rats. Hcl/ethanol administration caused significant damage to the gastric mucosa, as confirmed by gastric ulcer index and histological evaluation. However, this damage was largely prevented by pre-administering 20�mg/kg omeprazole or 100�mg/kg OLE. Interestingly, the damage was completely prevented by pre-administering 200 and 300�mg/kg OLE. Moreover, OLE attenuated the inflammatory response by decreasing nuclear factor-?B (NF-?B), cycloxygenase-2 (COX-2) and tumor necrosis factor-? (TNF-?) expressions, and down-regulating inducible nitric oxide synthase (iNOS) and interleukin-1? (IL-1?) in gastric mucosa. The gastroprotective mechanism of OLE involved the promotion of enzymatic and nonenzymatic molecules (superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase and glutathione reduced form), promoting nuclear factor erythroid 2-related factor 2 (Nrf2) mRNA expression, halting lipid peroxidation and preventing the overproduction of nitric oxide. Together, our findings clearly demonstrated that OLE could prevent HCl/ethanol-induced gastritis by attenuating inflammation and oxidant/antioxidant imbalance. Indeed, OLE could potentially be useful as a natural therapy for gastritis. � 2017 Elsevier Masson SASEnglishOctober University for Modern Sciences and ArtsUniversity of Modern Sciences and ArtsMSA Universityجامعة أكتوبر للعلوم الحديثة والآدابAntioxidantGastritisHCl/ethanolInflammationOlive leafalcoholcatalasecyclooxygenase 2digestive tract agentglutathione peroxidaseglutathione reductasehydrochloric acidimmunoglobulin enhancer binding proteininducible nitric oxide synthaseinterleukin 1betamessenger RNAmethanolnitric oxideOlea europaea extractomeprazoleplant extractsuperoxide dismutasetranscription factor Nrf2tumor necrosis factorunclassified drugalcoholantioxidanthydrochloric acidmethanolplant extractanimal experimentanimal modelanimal tissueArticlecontrolled studydown regulationenzyme activitygastritislipid peroxidationmalenonhumanoliveplant leafpriority journalprotein expressionratrat modelstomach mucosastomach protectionstomach ulceranimalbody weightchemically inducedchemistrydrug effectsenzymologygastritishigh performance liquid chromatographyinflammationmetabolismolive treeoxidative stresspathologyplant leafstomach ulcertoxicity testingWistar ratAnimalsAntioxidantsBody WeightChromatography, High Pressure LiquidEthanolGastritisHydrochloric AcidInflammationMaleMethanolOleaOxidative StressPlant ExtractsPlant LeavesRats, WistarStomach UlcerToxicity Tests, AcuteArticlehttps://doi.org/10.1016/j.biopha.2017.04.069PubMedID28463797