Mixed Tocopherols Have a Stronger Inhibitory Effect on Lipid Peroxidation Than α-Tocopherol Alone

Abstract

Intake of vitamin E with food (mixed tocopherols) has been found to counteract the development of atherosclerotic cardiovascular disease, whereas intake of large amounts of pure alpha-tocopherol has shown only a slight or no effect in clinical studies. This study was designed to investigate the effects of alpha-tocopherol alone and a mixed tocopherol preparation (gamma-, delta-, and alpha-tocopherol) on hydrogen peroxide-induced lipid peroxidation in human erythrocytes. Erythrocytes were incubated with different concentrations of alpha-tocopherol or mixed tocopherols and then exposed to hydrogen peroxide. Tocopherol levels and malondialdehyde-thiobarbituric acid-reactive substances were determined by high-performance liquid chromatography and fatty acids by gas chromatography. Incubation of erythrocytes with tocopherols (30-120 microM) increased the tocopherol level in a concentration-dependent manner. The uptake of gamma- and delta-tocopherols was much higher than that of alpha-tocopherol. Hydrogen peroxide strongly increased lipid peroxidation and decreased polyunsaturated fatty acids in erythrocytes. Both alpha-tocopherol and the tocopherol mixture protected the cells from lipid peroxidation, the mixture being much more potent than alpha-tocopherol alone. This study indicates that a mixture of tocopherols has a stronger inhibitory effect on lipid peroxidation induced in human erythrocytes than alpha-tocopherol alone, due to higher uptake of gamma- and delta-tocopherol in the cells.

Effects of vitamin E supplementation in the extender on frozen-thawed bovine semen preservation

“…Our findings are in agreement with those of Aitken and Clarkson (1988). Vitamin E is a collective term for eight naturally occurring compounds, four tocopherols (a, b, g and d) and four tocotrienols (a, b, g and d), which qualitatively exhibit the biological activities of a-tocopherol (Liu et al, 2002). Beconi et al (1991) confirmed that a-tocopherol in the extender used to freeze bovine semen decreased the level of lipid peroxidation.…”

Vitamin E isoform-specific inhibition of the exercise-induced heat shock protein 72 expression in humans

“…2F) supports the latter point of view. In vitro, a combination of ␣-, ␦-, and ␥-tocopherol is a more efficient inhibitor of lipid peroxidation in erythrocytes compared with ␣-tocopherol alone (40). The combination containing ␥-tocopherol, however, did not appear to be a more efficient antioxidant than the combination without ␥-tocopherol, at least when using the F 2 -isoprostane 8-iso-PGF 2␣ as marker of lipid peroxidation.…”

Oxidative stability of marine oils as affected by added wheat germ oil

“…[32,33] The content of α-tocopherol by itself was more than 32.85 mg/100 g of WGO, and the total tocopherol content of WGO was 124 mg/100 g. The large amount of tocopherols helped WGO to maintain good oxidative stability under accelerated oxidation conditions as mixed tocopherols possess strong capacity in preventing lipid oxidation. [34,35] The changes of tocopherols content in WGO was monitored throughout the experimental period, and 4% of total tocopherols were lost at the 72 h test point (Fig. 3).…”