Researchers of ZIOC analyzed various methods for assessing antioxidant activity

Antioxidants can be met in many areas of human life. Antioxidant systems are found in living organisms, and synthetic antioxidants are widely used as food additives and preservatives. The most important property of antioxidants is their ability to stop radical chains by intercepting free radicals. There are two main approaches to evaluate antioxidant activity: measurement of the oxidation potential, i.e. the ability of a compound to donate an electron to an oxidizing agent; and determining the reaction kinetics between an antioxidant and model free radicals, the most common of which is the stable radical 2,2-diphenyl-1-picrylhydrazyl (DPPH). These methods are based on various aspects of the chemical properties of the tested compounds, however, their results quite often correlate well. But there are a number of exceptions where the two methods give opposite results.

The aim of the recent study by scientists from the Laboratory of Chemistry of Carbenes and Other Unstable Molecules of the Zelinsky Institute was to directly compare two methods for assessing antioxidant activity using various mono- and polyphenols as examples. It was found that there were a number of factors that affect both the oxidation potential of the corresponding compound and the rate of its scavenging by radicals. It was concluded that there was a complex balance between electron donation capacity and free radical scavenging capacity, and that neither approach can accurately predict antioxidant capacity. Thus, at present, a combination of conceptually different and therefore complementary methods, both experimental and theoretical, is the most effective approach to finding the best antioxidants.

Source:

Anna Ya. Akyeva, Artem V. Kansuzyan, Katarina S. Vukich, Leah Kuhn, Evgeniya A. Saverina, Mikhail E. Minyaev, Valery M. Pechennikov, Mikhail P. Egorov, Igor V. Alabugin, Stepan V. Vorobyev, Mikhail A. Syroeshkin Remote Stereoelectronic Effects in Pyrrolidone- and Caprolactam-Substituted Phenols: Discrepancies in Antioxidant Properties Evaluated by Electrochemical Oxidation and H‑Atom Transfer Reactivity J. Org. Chem. 2022, 87, 5371–5384. DOI: 10.1021/acs.joc.2c00207.