title: Mixed tocopherols have a stronger inhibitory effect on lipid peroxidation than alpha-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.
authors.affiliation: Department of Surgery, Section of Forensic Medicine, University of Uppsala, Sweden.
authors.forename: Meilin
authors.initials: M
authors.lastname: Liu
authors.forename: Rolf
authors.initials: R
authors.lastname: Wallin
authors.forename: Agneta
authors.initials: A
authors.lastname: Wallmon
authors.forename: Tom
authors.initials: T
authors.lastname: Saldeen
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D000975:Antioxidants / Q000493:pharmacokinetics / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004912:Erythrocytes / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D015227:Lipid Peroxidation / Q000187:drug effects* / Q000502:physiology; D008875:Middle Aged; D019999:Pharmaceutical Solutions / Q000493:pharmacokinetics / Q000494:pharmacology; D024505:Tocopherols / Q000097:blood / Q000493:pharmacokinetics / Q000494:pharmacology*; D024502:alpha-Tocopherol / Q000097:blood / Q000493:pharmacokinetics / Q000494:pharmacology*
chemical_list: D000975:Antioxidants; D019999:Pharmaceutical Solutions; D024502:alpha-Tocopherol; D024505:Tocopherols