Versatile redox chemistry complicates antioxidant capacity assessment

Author(s)
Vladimir Chobot, Lenka Kubicova, Gert Bachmann, Franz Hadacek
Abstract

Some antioxidants have been shown to possess additional pro-oxidant effects. Diverse methodologies exist for studying redox properties of synthetic and natural chemicals. The latter are substantial components of our diet. Exploration of their contribution to life-extending or -compromising effects is mandatory. Among reactive oxygen species (ROS), hydroxyl radical (•OH) is the most damaging species. Due to its short half-life, the assay has to contain a specific generation system. Plants synthesize flavonoids, phenolic compounds recognized as counter-agents to coronary heart disease. Their antioxidant activities are affected by their hydroxylation patterns. Moreover, in the plant, they mainly occur as glycosides. We chose three derivatives, quercetin, luteolin, and rutin, in attempts to explore their redox chemistry in contrasting hydrogen peroxide environments. Initial addition of hydrogen peroxide in high concentration or gradual development constituted a main factor affecting their redox chemical properties, especially in case of quercetin. Our study exemplifies that a combination of a chemical assay (deoxyribose degradation) with an electrochemical method (square-wave voltammetry) provides insightful data. The ambiguity of the tested flavonoids to act either as anti- or pro-oxidant may complicate categorization, but probably contributed to their evolution as components of a successful metabolic system that benefits both producer and consumer.

Organisation(s)
Journal
International Journal of Molecular Sciences
Volume
14
Pages
11830-41
No. of pages
12
ISSN
1661-6596
DOI
https://doi.org/10.3390/ijms140611830
Publication date
06-2013
Peer reviewed
Yes
Austrian Fields of Science 2012
106002 Biochemistry, 106023 Molecular biology, 106034 Phytochemistry
Portal url
https://ucris.univie.ac.at/portal/en/publications/versatile-redox-chemistry-complicates-antioxidant-capacity-assessment(1e8ab10e-917b-4ef8-a6c1-19e2c59609ba).html