Free radical scavenging by natural polyphenols: Atom versus electron transfer

Florent Di Meo, Vincent Lemaur, Jéroîme Cornil, Roberto Lazzaroni, Jean Luc Duroux, Yoann Olivier, Patrick Trouillas

Research output: Contribution to journalArticlepeer-review


Polyphenols (synthetically modified or directly provided by human diet) scavenge free radicals by H-atom transfer and may thus decrease noxious effects due to oxidative stress. Free radical scavenging by polyphenols has been widely theoretically studied from the thermodynamic point of view whereas the kinetic point of view has been much less addressed. The present study describes kinetic-based structure-activity relationship for quercetin. This compound is very characteristic of the wide flavonoid subclass of polyphenols. H-atom transfer is a mechanism based on either atom or electron transfer. This is analyzed here by quantum chemical calculations, which support the knowledge acquired from experimental studies. The competition between the different processes is discussed in terms of the nature of the prereaction complexes, the pH, the formation of activated-deprotonated forms, and the atom- and electron-transfer efficiency. The role of the catechol moiety and the 3-OH group of quercetin as scavengers of different types of free radicals (CH 3OO, CH3O, OH, and CH2OH) is rationalized. Identifying the exact mechanism and accurately evaluating kinetics is of fundamental importance to understand antioxidant behavior in physiological environments.

Original languageEnglish
Pages (from-to)2082-2092
Number of pages11
JournalJournal of physical chemistry A
Issue number10
Publication statusPublished - 14 Mar 2013
Externally publishedYes


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