title: Effect of Selected Plant Phenolics on Fe2+-EDTA-H₂O₂ System Mediated Deoxyribose Oxidation: Molecular Structure-Derived Relationships of Anti- and Pro-Oxidant Actions.
abstract: In the presence of transition metal ions and peroxides, polyphenols, well-known dietary antioxidants, can act as pro-oxidants. We investigated the effect of 13 polyphenols and their metabolites on oxidative degradation of deoxyribose by an•OH generating Fenton system (Fe2+-ethylenediaminetetraacetic acid (EDTA)-H₂O₂). The relationship between phenolics pro-oxidant/anti-oxidant effects and their molecular structure was analyzed using multivariate analysis with multiple linear regression and a backward stepwise technique. Four phenolics revealed a significant inhibitory effect on OH-induced deoxyribose degradation, ranging from 54.4% ± 28.6% (3,4-dihydroxycinnamic acid) to 38.5% ± 10.4% (catechin) (n= 6), correlating with the number of -OH substitutions (r= 0.58). Seven phenolics augmented the oxidative degradation of deoxyribose with the highest enhancement at 95.0% ± 21.3% (quercetin) and 60.6% ± 12.2% (phloridzin). The pro-oxidant effect correlated (p< 0.05) with the number of -OH groups (r= 0.59), and aliphatic substitutes (r= -0.22) and weakly correlated with the occurrence of a catechol structure within the compound molecule (r= 0.17). Selective dietary supplementation with phenolics exhibiting pro-oxidant activity may increase the possibility of systemic oxidative stress in patients treated with medications containing chelating properties or those with high plasma concentrations of H₂O₂ and non-transferrin bound iron.
authors.affiliation: Heart and Vascular Institute of North Florida, 2623 Centennial Blvd., Suite 102, Tallahassee, FL 32308, USA. adegraft@umich.edu.
authors.forename: Jeffrey
authors.initials: J
authors.lastname: de Graft-Johnson
authors.affiliation: Department of Clinical Physiology, Medical University of Lodz, Mazowiecka 6/8, 92-215 Lodz, Poland. dariusz.nowak@umed.lodz.pl.
authors.forename: Dariusz
authors.initials: D
authors.lastname: Nowak
mesh_terms: D000975:Antioxidants / Q000737:chemistry*; D003855:Deoxyribose / Q000737:chemistry / Q000378:metabolism*; D004492:Edetic Acid / Q000737:chemistry*; D005638:Fruit / Q000737:chemistry; D006801:Humans; D006861:Hydrogen Peroxide / Q000737:chemistry; D016877:Oxidants / Q000737:chemistry*; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D010636:Phenols / Q000737:chemistry*; D010936:Plant Extracts / Q000737:chemistry*; D014675:Vegetables / Q000737:chemistry
chemical_list: D000975:Antioxidants; D016877:Oxidants; D010636:Phenols; D010936:Plant Extracts; D003855:Deoxyribose; D004492:Edetic Acid; D006861:Hydrogen Peroxide
keywords: Fenton system; hydroxyl radicals; plant phenolic acids; polyphenols