title: Antioxidant activity of olive phenols and other dietary phenols in model gastric conditions: Scavenging of the free radical DPPH and inhibition of the haem-induced peroxidation of linoleic acid.
abstract: The antioxidant activity of dietary phenols in humans (direct reduction of radicals and other highly oxidizing species) could be largely restricted to fighting postprandial oxidative stress in the gastric compartment. Hence, the development of chemical tests simply modelling this situation is pertinent. In this work, the antioxidant properties of the olive phenols hydroxytyrosol and oleuropein are investigated in pH 5-6 micellar solutions through the reduction of the DPPH radical and the inhibition of the metmyoglobin-induced peroxidation of linoleic acid. In the first test, hydroxytyrosol and oleuropein proved as efficient as common polyphenols and their reactivity was only moderately affected by β-cyclodextrin and bovine serum albumin, taken as models of food macromolecules. In the second test, hydroxytyrosol and oleuropein by themselves came up as relatively weak inhibitors, despite their efficiency at reducing hypervalent haem iron. However, hydroxytyrosol was able to act in synergy with the typical chain-breaking antioxidant α-tocopherol.
authors.affiliation: Laboratory of Biomathematics, Biochemistry, Biophysics and Scientometrics, Faculty of Natural Sciences and Life, University of Bejaia, Bejaia 06000, Algeria.
authors.forename: Sabiha
authors.initials: S
authors.lastname: Achat
authors.affiliation: University of Avignon, INRA, UMR408, Safety & Quality of Plant Products, 84000 Avignon, France.
authors.forename: Njara
authors.initials: N
authors.lastname: Rakotomanomana
authors.affiliation: Laboratory of Biomathematics, Biochemistry, Biophysics and Scientometrics, Faculty of Natural Sciences and Life, University of Bejaia, Bejaia 06000, Algeria.
authors.forename: Khodir
authors.initials: K
authors.lastname: Madani
authors.affiliation: University of Avignon, INRA, UMR408, Safety & Quality of Plant Products, 84000 Avignon, France. Electronic address: olivier.dangles@univ-avignon.fr.
authors.forename: Olivier
authors.initials: O
authors.lastname: Dangles
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D002417:Cattle; D004032:Diet; D005609:Free Radicals / Q000737:chemistry*; D005753:Gastric Mucosa / Q000378:metabolism; D006418:Heme / Q000737:chemistry*; D006801:Humans; D019787:Linoleic Acid / Q000737:chemistry*; D015227:Lipid Peroxidation / Q000187:drug effects*; D008954:Models, Biological; D031658:Olea / Q000737:chemistry*; D010084:Oxidation-Reduction; D018384:Oxidative Stress / Q000187:drug effects; D010636:Phenols / Q000494:pharmacology*; D013270:Stomach / Q000187:drug effects; D024502:alpha-Tocopherol / Q000494:pharmacology; D047392:beta-Cyclodextrins / Q000737:chemistry
chemical_list: D000975:Antioxidants; D005609:Free Radicals; D010636:Phenols; D047392:beta-Cyclodextrins; D006418:Heme; D019787:Linoleic Acid; D024502:alpha-Tocopherol
keywords: Antioxidant; DPPH; Haem; Lipid peroxidation; Metmyoglobin; Olive; Phenols