Redox factors in the antioxidant activity of nitroxides toward DNA guanyl and 2-deoxyribose-peroxyl radicals
Year: 2024
Type: article
Abstract: A series of eight nitroxide compounds (four substituted piperidines, three pyrrolidines and one oxo-piperidine) are found to undergo electron transfer to 2’-deoxyribose-peroxyl and the guanyl radical. One-electron oxidation potentials of the nitroxides to oxoammonium cations (oxoammonium reduction potential), E0’, have been measured against a common redox indicator, chlorpromazine, and found to span the range 751 ± 15 mV to 973 ± 15 mV. Fast chemical reduction of the 2’-deoxyribose-peroxyl radical to the hydroperoxide, generated by •OH radical attack on 2-deoxyribose, dR, in oxygenated aqueous solution, is a redox-dependent reaction, with rate constants of 0.8–3.5 x 107 M−1 s−1.The guanyl radicals, produced upon one-electron oxidation of 2’-deoxyguanosine monophosphate, dG, by the selenite radical, SeO3•-, react with the nitroxides in a redox-independent reaction with diffusion rate constants of 1–2 x 108 M−1 s−1. These findings represent a possible antioxidant role for nitroxides in the fast chemical repair of DNA radicals, which is supported by an in vitro strand break study using a plasmid.
Source: Free Radical Research
Authors: Wen Qi, Smitha U. Nair, David I. Pattison, Robert F. Anderson
Language: English
Subfield: Organic Chemistry
Field: Chemistry
Domain: Physical Sciences
Open Access status: hybrid
OpenAlex ID: W4403730748