title: Synergistic antioxidant effect of catechin and malvidin 3-glucoside on free radical-initiated peroxidation of linoleic acid in micelles.
abstract: The inhibitory effect of anthocyanins has been investigated in the peroxidation of linoleic acid in micelles in the presence and in the absence of (+)-catechin. The peroxidation was initiated by thermal decomposition of 2,2(')-azobis[2-(2-imidazolin-2-yl)propane], and the kinetics of peroxidation were followed by measuring the rate of oxygen consumption and the rate of disappearance of the antioxidant. The analysis of the antioxidant effect of various anthocyanins, alone or in the presence of catechin, demonstrates that catechin, which is relatively inefficient at inhibiting linoleic acid oxidation, regenerates the highly efficient antioxidant malvidin 3-glucoside and, at a lower extent, peonidin 3-glucoside. The malvidin 3-glucoside recycling by catechin strongly increases the antioxidant efficiency of these two antioxidants. This protective mechanism appears specific for malvidin and peonidin 3-glucosides. The high unpaired spin density of the phenolic O atoms in the radicals generated by these anthocyanins, calculated by the semiempirical quantum chemical AM1 method, may explain the observed behavior.
authors.affiliation: Dipartimento di Chimica Biologica, Università di Padova, 35121 Padova, Italy.
authors.forename: Monica
authors.initials: M
authors.lastname: Rossetto
authors.forename: Paola
authors.initials: P
authors.lastname: Vanzani
authors.forename: Fulvio
authors.initials: F
authors.lastname: Mattivi
authors.forename: Michele
authors.initials: M
authors.lastname: Lunelli
authors.forename: Marina
authors.initials: M
authors.lastname: Scarpa
authors.forename: Adelio
authors.initials: A
authors.lastname: Rigo
mesh_terms: D000872:Anthocyanins / Q000494:pharmacology*; D000975:Antioxidants / Q000494:pharmacology*; D001391:Azo Compounds / Q000737:chemistry; D002392:Catechin / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D005609:Free Radicals / Q000378:metabolism; D005960:Glucosides / Q000494:pharmacology; D007093:Imidazoles / Q000737:chemistry; D020128:Inhibitory Concentration 50; D019787:Linoleic Acid / Q000378:metabolism*; D015227:Lipid Peroxidation / Q000187:drug effects*; D008077:Lipoproteins, LDL / Q000737:chemistry; D008823:Micelles; D010100:Oxygen / Q000378:metabolism
chemical_list: D000872:Anthocyanins; D000975:Antioxidants; D001391:Azo Compounds; D005609:Free Radicals; D005960:Glucosides; D007093:Imidazoles; D008077:Lipoproteins, LDL; D008823:Micelles; C430118:VA 061; C462279:cyanidin-3-O-beta-glucopyranoside; C455107:petunidin-3-glucoside; C458419:malvidin-3-glucoside; D002392:Catechin; D019787:Linoleic Acid; D010100:Oxygen