[Lecithin influence on the effectiveness of the antioxidant effect of flavonoids and alpha-tocopherol].

Influence of the widely used food supplement lecithin on the effectiveness of the inhibiting effect of the natural antioxidants (quercitin, dihydroquercitin, and alpha-tocopherol) has been studied in dependence of the rate of free radicals generation in the model oxidation reactions. It has been found that during the initiated and autoxidation of methyl oleat, lecithin decreased the antioxidant effectiveness of flavonoids. The effect value increased with the lecithin concentration increase. In similar conditions while oxidation inhibiting by alpha-tocopherol and lecithin mixtures, the latter did not influence the tocopherol antioxidant effectiveness (additivity) or led to the increase of the inhibition effectiveness (synergism).

[Effect of lecithin on the inhibitory efficiency of alpha-tocopherol during methyl oleate oxidation].

It has been established that the effect of lecithin on the oxidation of methyl oleate depends on the rate of the free radical initiation: lecithin does not affect the reaction rate at high rates of radical initiation (the initiated oxidation) and accelerates the oxidation at low rates (autooxidation), causing the reduction of the induction period. The inhibitory action of mixtures of lecithin and the natural antioxidant alpha-tocopherol depends on the concentrations of both alpha-tocopherol and lecithin at different rates of oxidation. The inhibitory efficiency of mixtures with low concentrations of alpha-tocopherol is close to additive. Increasing the initial concentration of alpha-tocopherol in mixtures causes a gain in the synergistic effect. The synergistic effect depends drastically on lecithin concentration at high concentrations of alpha-tocopherol. The mechanism of the synergistic effect for the mixtures of alpha-tocopherol and lecithin is discussed.

[The characteristics of the effect of dipalmitoylphosphatidylcholine and its structural fragments on the lipid peroxidation of biological membranes]. / Ossobennosti vliianiia dipal'mitoilfosfatidilkholina i ego strukturnykh fragmentov na perekisnoe okislenie lipidov biologicheskikh membran.

The effect of dipalmitoyl phosphatidylcholine (DPPC) and its structural fragments--phosphatidic acid (PA) and choline chloride--on the ascorbate-dependent mice liver microsomal lipid peroxidation (LP) has been studied at the different LP rate. At DPPC, PA and choline chloride introduction into the incubation medium before the onset of peroxidation induction DPPC causes the more considerable inhibition of LP than PA each separate fragment. The inhibition effect of DPPC is lower than PA or choline chloride when DPPC, PA and choline chloride added on the background of developing process of peroxidation (e.i. after LP induction). A specific regulatory role of PC in the normal cell membrane LP process and during pathologic development is under discussion.

[Effect of lecithin on liver microsomal lipid peroxidation]. / Vliianie letsitina na perekisnoe okislenie lipidov v mikrosomakh pecheni.

The effect of exogeneous (egg) lecithin on peroxidation of microsomal lipids was studied with the view of elucidating the role of various components of lipid substrate in the overall oxidation rate of the lipids. The following processes were studied a) NADPH-dependent microsomal lipid peroxidation in the presence of lecithin; b) ascorbate-dependent microsomal lipid peroxidation in the presence of lecithin; c) oxidation of lipid mixture, isolated from the microsomes, and that of lecithin in the presence of the Fe2+ + ascorbate system; 4) oxidation of lecithin induced by the Fe2+ + ascorbate system. It was found that in the presence of exogeneous lecithin the oxidation of microsomal lipids in inhibited, which is probably due to the peculiarities of lecithin oxidation. It was shown that the specific rate of lecithin oxidation is decreased with an increase in lecithin concentration. Possible mechanisms of lecithin effect on microsomal lipid peroxidation are discussed.