Effect of Selected Plant Phenolics on Fe2+-EDTA-H2O2 System Mediated Deoxyribose Oxidation: Molecular Structure-Derived Relationships of Anti- and Pro-Oxidant Actions

• Published in: Molecules (Basel, Switzerland) Switzerland), 2017-01, Vol.22 (1), p.59-59
• Main Authors: De Graft-Johnson, Jeffrey, Nowak, Dariusz
• Format: Article
• Language: English
• Subjects: Acetic acid; Antioxidants; Catechin; Catechol; Chelation; Correlation; Degradation; Edetic acid; Ethylenediaminetetraacetic acids; Fenton system; Ferrous ions; Hydrogen peroxide; hydroxyl radicals; Iron; Metabolites; Molecular structure; Multivariate analysis; Oxidants; Oxidation; Oxidative stress; Oxidizing agents; Peroxides; plant phenolic acids; Polyphenols; Quercetin; Transferrin; Transferrins; Transition metals
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules22010059

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.