The relationship between antioxidant activity, first electrochemical oxidation potential, and spin population of flavonoid radicals

  • Ante Miličević Institute for Medical Research and Occupational Health, Zagreb
Keywords: DFT, oxidation potential, PM6, polyphenols, radical scavenging


I have shown that by averaging antioxidant activity (AA) values measured by different methods it is possible to obtain an excellent correlation (R2=0.960) between the first electrochemical oxidation potential, Ep1, and AA. Separate correlations using the AA values obtained with each of the four methods [R2 were 0.599 for diphenyl-1-picrylhydrazyl (DPPH), 0.884 for Folin Ciocalteu reagent (FCR), 0.953 for the ferric-reducing ability of plasma (FRAP), and 0.719 for the Trolox equivalent antioxidant capacity (TEAC)] were all worse, and in some cases not useful at all, such as the one for DPPH. Also, the sum of atomic orbital spin populations on the carbon atoms in the skeleton of radicals (AOSPRad), calculated with the semi-empirical parameterisation method 6 (PM6) in water, was used to correlate both Ep1 and AA, yielding R2=0.926 and 0.950, respectively. This showed to be a much better variable for the estimation of Ep1 and AA than the bond dissociation energy (BDE), R2=0.854 and 0.901 for Ep1 and AA, respectively, and especially the ionisation potential (IP), R2=0.445 and 0.435 for Ep1 and AA, respectively.


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How to Cite
Miličević A. The relationship between antioxidant activity, first electrochemical oxidation potential, and spin population of flavonoid radicals. Arh Hig Rada Toksikol [Internet]. 2019May30 [cited 2024May20];70(2). Available from:
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