An extra-virgin olive oil rich in polyphenolic compounds has antioxidant effects in OF1 mice.
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.
Oliveras-López
María-Jesús
MJ
Department of Molecular Biology and Biochemistry Engineering, Andalusian Center of Molecular Biology and Regenerative Medicine, CIBERDEM, University of Pablo de Olavide of Seville, 41092 Seville, Spain.
Berná
Genoveva
G
Carneiro
Everardo M
EM
López-García de la Serrana
Herminia
H
Martín
Franz
F
López
M Carmen
MC
D000818:Animals; D000975:Antioxidants / Q000737:chemistry* / Q000494:pharmacology*; D002462:Cell Membrane / Q000187:drug effects; D004032:Diet; D019587:Dietary Supplements; D006861:Hydrogen Peroxide / Q000494:pharmacology; D015227:Lipid Peroxidation; D008099:Liver / Q000187:drug effects; D008297:Male; D008315:Malondialdehyde / Q000378:metabolism; D051379:Mice; D008815:Mice, Inbred Strains; D000069463:Olive Oil; D010938:Plant Oils / Q000737:chemistry* / Q000494:pharmacology*; D000074242:Sunflower Oil
D000975:Antioxidants; D000069463:Olive Oil; D010938:Plant Oils; D000074242:Sunflower Oil; D008315:Malondialdehyde; D006861:Hydrogen Peroxide