The nitroxide Tempo inhibits hydroxyl radical production from the Fenton-like reaction of iron(II)-citrate with hydrogen peroxide
| Autor: | Fengqiang Shi, Yujia Mao, Peifeng Zhang, Can Wang, Zhongwei Zhao, Meiqing Zheng |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
inorganic chemicals
0301 basic medicine Nitroxide mediated radical polymerization Iron Biophysics Photochemistry medicine.disease_cause Biochemistry law.invention Cyclic N-Oxides 03 medical and health sciences chemistry.chemical_compound 0302 clinical medicine law medicine Citrates Ferrous Compounds Hydrogen peroxide Electron paramagnetic resonance Molecular Biology chemistry.chemical_classification Reactive oxygen species Chemistry Ligand Hydroxyl Radical Electron Spin Resonance Spectroscopy Cell Biology Hydrogen Peroxide 030104 developmental biology Spectrometry Fluorescence 030220 oncology & carcinogenesis Hydroxyl radical Spectrophotometry Ultraviolet Oxidation-Reduction Stoichiometry Oxidative stress |
| Zdroj: | Biochemical and biophysical research communications. 483(1) |
| ISSN: | 1090-2104 |
| Popis: | In vivo physiological ligand citrate can bind iron(II) ions to form the iron(II)-citrate complex. Inhibition of hydroxyl radical (OH) production from the Fenton-like reaction of iron(II)-citrate with H2O2 is biologically important, as this reaction may account for one of the mechanisms of the labile iron pool in vivo to induce oxidative stress and pathological conditions. Nitroxides have promising potentials as therapeutic antioxidants. However, there are controversial findings indicating that they not only act as antioxidants but also as pro-oxidants when engaged in Fenton reactions. Although the underlying mechanisms are proposed to be the inhibition or enhancement of the OH production by nitroxides, the proposed elucidations are only based on assessing biological damages and not demonstrated directly by measuring the OH production in the presence of nitroxides. In this study, therefore, we employed EPR and fluorescence spectroscopies to show direct evidence that nitroxide 2,2,6,6-tetramethyl-piperidine-1-oxyl (Tempo) inhibited OH production from the Fenton-like reaction of iron(II)-citrate with H2O2 by up to 90%. We also demonstrated spectrophotometrically, for the first time, that this inhibition was due to oxidation of the iron(II)-citrate by Tempo with a stoichiometry of Tempo:Iron(III)-citrate = 1.1:1.0. A scheme was proposed to illustrate the roles of nitroxides engaged in Fenton/Fenton-like reactions. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect