ИСТИНА

The oxidation strees caused by an excessive generation of reactive oxygen species (ROS) such as superoxide radical-anion O2.-, hydroxyl HO., peroxyl radicals LOO , lipid hydroperoxides LOOH leds to ardiovascular diseases, mutagenic changes, cancerous tumor growth and ageing of living organisms on whole. Therefore, the search for novel effective antioxidants and antioxidant activity assays is topical task [1]. The novel electrochemical approach based on the hydrogen transfer reaction to the stable radical 2,2-diphenyl-1-picrylhydrazyl DPPH was developed [2,3]. The reaction was monitored using cyclic voltammetry (CV) and rotating disk electrode (RDE) techniques. CV and the polarization curves of DPPH displays two one-electron reversible waves corresponding, accordingly, to oxidation and reduction of this radical. Thus, one can study the kinetic dependance of this reaction using the peak current of CV and/or limiting diffusion current value of the polarization curve I/I0 = C/C0 (there I0 is the current value at the initial concentration of DPPH C0, I – the current value at the concentration C corresponding given moment of time). This method was applied to antioxidant properties study of wide range of compounds: porphyrins and metalloporphyrins with alkyl moieties; ferrocenes; complexes of phosphonates, containing 2,6-di-tert-butyl groups, with organotin compounds R2SnCl2 ( R = Me, Et, n-Bu, Ph); complexes of biometals ( Cu, Fe, Co, Mn, Zn, Ni) with ligand containing 2,6-di-tert-butylphenol and dipicolylamine fragments. It was shown that the correlation between redox properties and antioxidant effectivity takes place: the easily oxidized compounds demonstrate higher activity. The data of electrochemical study are in agreement with results derived by the spectrophotometrical and biological methods. The possible mechanism of antioxidant action is discussed.