title: Effects of selected dietary secondary metabolites on reactive oxygen species production caused by iron(II) autoxidation.
abstract: Iron is an essential co-factor for many enzymes that catalyze electron transfer reactions. It is well known that so-called "poorly liganded" iron can increase ROS concentrations and trigger oxidative stress that is capable of initiating apoptosis. Conversely, controlled ROS production has been recognized as an integral part of cellular signaling. Elevated ROS concentrations are associated with aging, inflammatory and degenerative diseases. Anti-aging properties have been attributed especially to antioxidant phenolic plant metabolites that represent food additives in our diet. Consequently, this study explores the effects of flavonoids (quercetin and rutin), several phenolic acids (caffeic, chlorogenic, and protocatechuic acid), and the alkaloid caffeine on iron(II) autoxidation and ROS production in comparison to the standard antioxidants ascorbic acid and Trolox. The iron(II) autoxidation assay was carried out in pH 6.0 (plant apoplast and inflamed human tissue) and 7.4 (cell cytoplasm and human blood plasma). The obtained results accentuate phenolic acids as the more specific antioxidants compared to ascorbic acid and Trolox. Flavonoid redox chemistry depends more on the chemical milieu, specifically on pH. In vivo, the presence of iron cannot be ruled out and "wrongly" or "poorly" complexed iron has been pointed out as causative agent of various age-related diseases.
authors.affiliation: Division of Molecular Systems Biology, Department of Ecogenomics and Systems Biology, Faculty of Life Sciences, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria. vladimir.chobot@univie.ac.at.
authors.forename: Vladimir
authors.initials: V
authors.lastname: Chobot
authors.affiliation: Department of Plant Biochemistry, Albrecht-von-Haller Institut, Georg-August-Universität Göttingen, Justus-von-Liebig-Weg 11, D-37077 Göttingen, Germany. franz.hadacek@biologie.uni-goettingen.de.
authors.forename: Franz
authors.initials: F
authors.lastname: Hadacek
authors.affiliation: Division of Molecular Systems Biology, Department of Ecogenomics and Systems Biology, Faculty of Life Sciences, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria. lenka.kubicova@univie.ac.at.
authors.forename: Lenka
authors.initials: L
authors.lastname: Kubicova
mesh_terms: D001681:Biological Assay; D004032:Diet; D005419:Flavonoids / Q000737:chemistry / Q000494:pharmacology*; D006801:Humans; D007501:Iron / Q000378:metabolism*; D010084:Oxidation-Reduction / Q000187:drug effects; D010636:Phenols / Q000737:chemistry / Q000494:pharmacology*; D017382:Reactive Oxygen Species / Q000378:metabolism*; D064210:Secondary Metabolism
chemical_list: D005419:Flavonoids; D010636:Phenols; D017382:Reactive Oxygen Species; D007501:Iron