ABSTRACT
The comparison study of kinetic regularities of primary (dienic conjugates - DC) and secondary (malonic dialdehyde - MDA) accumulation, unsaturated lipid substrate (double bonds - DB) consumption during spontaneous and Fe2+-ascorbate initiated peroxide oxidation of lipids (POL) in endoplasmic reticulum membranes of mouse liver cells in vitro is carried out. On these models, the action of natural (^-tocopherol - oTP) and synthetic (phenosan potassium salt - PPS) antioxidants in concentrations between 10"18 and 10'3 M was also studied. It is found that a-TP and PPS inhibit both spontaneous and initiated POL, estimated by DC and DB criteria, within the concentration ranges of 10"5 - 10~6 and 10"8 - 10-18 M. For MDA used as the criterion, an effect sign change is observed for PPS: POL inhibition in the range of 1(T4-1(T,0M is converted to POL promotion in the range of 10 - 10"15 M. In the case of use of all three criteria, the dose-effect dependencies for a-TP and PPS show typical maxima at high and ultra-low concentrations and the "silent zone between these maxima, though the extension of this zone is different for a-TP and PPS. Such regularities are typical of biologically active substances demonstrating the current effect at ultra-low concentrations. The correlation analysis, carried out for the purpose of estimating the effect of antioxidants on two oxidation models by three above-mentioned criteria, allows for a conclusion about advantages of the use of spontaneous POL model and DC and DB change criteria for the estimation of POL inhibition. The studies carried out with the spin probe method, allow for a supposition that a definite role in the mechanism of antioxidant action play the structural changes happening in membranes.
