<abstract xmlns="http://www.w3.org/1999/xhtml"><p>Very recently, a report on the antioxidant activity of flavonoids has appeared, where authors concluded that Hydrogen Atom Transfer mechanism represents the thermodynamically preferred mechanism in polar media (<ext-link ext-link-type="uri" xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="https://doi.org/10.1016/j.foodres.2018.11.018">https://doi.org/10.1016/j.foodres.2018.11.018</ext-link>). Unfortunately, serious errors in the theoretical part of the paper led to incorrect conclusions. For six flavonols (galangin, kaempferol, quercetin, morin, myricetin, and fisetin), reaction enthalpies related to three mechanisms of the primary antioxidant action were computed. Based on the obtained results, the role of intramolecular hydrogen bonds (IHB) in the thermodynamics of the antioxidant effect is presented. Calculations and the role of solvation enthalpies of proton and electron in the determination of thermodynamically preferred mechanism is also briefly explained and discussed. The obtained results are in accordance with published works considering the Sequential Proton-Loss Electron-Transfer thermodynamically preferred reaction pathway.</p></abstract>

Very recently, a report on the antioxidant activity of flavonoids has appeared, where authors concluded that Hydrogen Atom Transfer mechanism represents the thermodynamically preferred mechanism in polar media (https://doi.org/10.1016/j.foodres.2018.11.018). Unfortunately, serious errors in the theoretical part of the paper led to incorrect conclusions. For six flavonols (galangin, kaempferol, quercetin, morin, myricetin, and fisetin), reaction enthalpies related to three mechanisms of the primary antioxidant action were computed. Based on the obtained results, the role of intramolecular hydrogen bonds (IHB) in the thermodynamics of the antioxidant effect is presented. Calculations and the role of solvation enthalpies of proton and electron in the determination of thermodynamically preferred mechanism is also briefly explained and discussed. The obtained results are in accordance with published works considering the Sequential Proton-Loss Electron-Transfer thermodynamically preferred reaction pathway.

Thermodynamics of primary antioxidant action of flavonols in polar solvents

Institute of Physical Chemistry and Chemical Physics

Slovak University of Technology in Bratislava

Acta Chimica Slovaca

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

{"article-title":"Thermodynamics of primary antioxidant action of flavonols in polar solvents"}

Very recently, a report on the antioxidant activity of flavonoids has appeared, where authors concluded that Hydrogen Atom Transfer mechanism represents the...

Thermodynamics of primary antioxidant action of flavonols in polar solvents

Published Online: Jul 09, 2019

Page range: 108 - 118

DOI: https://doi.org/10.2478/acs-2019-0016

Keywords
phenolic antioxidant, intramolecular hydrogen bond, DFT calculation, sequential proton-loss electron-transfer, solvent effect

© 2019 Martin Michalík et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

Thermodynamics of primary antioxidant action of flavonols in polar solvents

Published Online: Jul 09, 2019

Page range: 108 - 118

DOI: https://doi.org/10.2478/acs-2019-0016

Keywordsphenolic antioxidant, intramolecular hydrogen bond, DFT calculation, sequential proton-loss electron-transfer, solvent effect

© 2019 Martin Michalík et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

Keywords
phenolic antioxidant, intramolecular hydrogen bond, DFT calculation, sequential proton-loss electron-transfer, solvent effect