Abstract

A series of 2,6-di-tert-butylphenols with pyridine moiety and their hydrophilic forms were synthesized and characterized by NMR, IR, X-ray and elemental analysis. The redox properties of compounds were studied by cyclic voltammetry (CV). Chemical oxidation of compounds under investigation leading to relatively stable radicals was studied by EPR. Antioxidant activity was evaluated in model reactions of hydrogen atom abstraction (DPPH-test) and one-electron reduction (CUPRAC-test). It was shown that modified 2,6-di-tert-butylphenols possess radical scavenging activity of prolonged action, achieving its maximum on 20 h time spans. The antioxidant properties in vitro in oxidation of linoleic acid by lipoxygenase, in reaction with superoxide radical-anion generated from xanthine/xanthine-oxidase enzymatic system, and in induced lipid peroxidation of rat liver homogenates were studied. The study of lipid peroxidation demonstrated high antioxidant activity for both lipophilic and hydrophilic compounds. The “structure-activity” analysis shows that the length of the linker between functional groups and position of substituent in pyridine cycle affects the antioxidant activity. Results of this study open the scopes for the search of novel water-soluble cyto-, neuroprotectors and physiologically active compounds with antioxidant mode of action.

Keywords

2,6-di-tert-butylphenol, pyridines, antioxidants, X-ray analysis, DPPH, ROS, radical scavenging activity, electrochemistry, EPR, lipid peroxidation