An Extra-Virgin Olive Oil Rich in Polyphenolic Compounds Has Antioxidant Effects in Of1 Mice

Abstract

Extra-virgin olive oil (OO) is becoming more important in daily diets due to its beneficial effects on health, most of which are because of its antioxidant content. We studied the antioxidant activity and mechanisms of an extra-virgin OO that is rich in phenolics on pancreatic islets and liver in control mice (CTL) fed a nonpurified diet and in mice supplemented with 50 microL/d sunflower oil (SO) or 50 microL/d extra-virgin OO for 4 d. Plasma hydroxytyrosol concentration was determined by HPLC-diode array detector. Plasma antioxidant capacity, enzymatic activities, and lipid peroxidation were measured by spectrophotometry. Islet function was studied by measuring insulin release. Islet cell gene expression was examined using quantitative RT-PCR. The plasma hydroxytyrosol concentration was greater in OO mice than in CTL or SO mice (P < 0.05) and was greater in SO mice than in CTL mice. The ratio of reduced:oxidized glutathione and the antioxidant capacity in plasma was greater in OO mice than in CTL or SO mice (P < 0.05) and higher in SO mice than in CTL mice. Glucose-stimulated insulin secretion was greater in OO mice than in CTL or SO mice (P < 0.05) and was also higher in SO mice than in CTL mice. Protection against liver cell and beta cell membrane lipid peroxidation was greater in OO mice than in CTL or SO mice (P < 0.05) and was greater in SO mice than in CTL mice. Catalase (CAT) expression in the islet of Langerhans was higher in OO mice than in CTL mice and SO mice (P < 0.05). The CAT and glutathione peroxidase 1 activities in the islet of Langerhans were 25% greater in OO mice than in CTL mice and higher than in SO mice (P < 0.05) and they were greater in SO mice than in CTL mice. These results indicate that, in metabolic tissues, protection by extra-virgin OO against oxidative stress occurs primarily through a direct antioxidant effect as well as through an indirect mechanism that involves greater expression and activity of certain enzymes with antioxidant activities.

Oleuropein using as an Additive for Feed and Products used for Humans

“…Rabbits with induced diabetes showed a decrease in oxidative stress markers when treated with oleuropein [37]. Other experiments support the antioxidant activity of the phenols oleuropein and hydroxytyrosol [59].…”

“…Olive leaf has antioxidant properties associated with oleuropein. Oleuropein, hydroxytyrosol, and extracts of Olea europaea leaf (containing 19% oleuropein, 1.8% flavonoid glycosides, and 3,4-dihydroxy-phenethyl esters) were more potent antioxidants than vitamin E or another established antioxidant, in a model chemical system [59]. Oleuropein, as an antioxidant, has been reported to decrease the oxidation of low-density lipoproteins (LDL) cholesterol [60].…”

Pathomechanisms of Oxidative Stress in Inflammatory Bowel Disease and Potential Antioxidant Therapies

“…It has been used as a nutritional supplement for immune-deficient patients and may become a valuable replenishment for IBD patients [226]. EVOO consumption can activate antioxidant enzymes such as CAT, SOD, and GPX and regulate immune responses against oxidative stress to relieve IBD symptoms [227]. EVOO is widely reported to protect against colon cancer, which is a later stage of IBD progression [228].…”

Olive Oil and Cardiovascular Health

“…68 In agreement with this, olive oil feeding increased catalase and glutathione peroxidase expression in the islets of Langerhans in mice. 69 Few studies have analyzed the in vivo changes in gene expression associated with olive oil consumption in humans. In an ex vivo study, triglyceride-rich lipoproteins isolated from healthy volunteers after ingestion of a meal enriched with refined olive oil promoted a fewer atherogenic gene expression in smooth muscle cell of human coronary artery than triglyceride-rich proteins isolated after meals rich in butter or a mixture of vegetable and fish oils.…”