Antioxidant activities of tocopherols on Fe2+-ascorbate-induced lipid peroxidation in lecithin liposomes.
The antioxidant activities of 4 tocopherols, tocol, and a water-soluble model analog of alpha-tocopherol were compared. Egg lecithin liposomes were used and oxidation was catalyzed by Fe2+-ascorbate. The activities decreased in the order alpha greater than beta greater than gamma greater than delta-tocopherol greater than tocol, in agreement with their potencies in vivo. The water-soluble analog was the least effective. Activity depended on the molar ratio of antioxidant to unsaturated lipid, with one molecule each of the alpha-, beta-, gamma-, delta-tocopherol and tocol capable of protecting, respectively, 220, 120, 100, 30 and 20 molecules of polyunsaturated fatty acid. The mechanism of possible antioxidant effect of the compounds used is discussed.
D001205:Ascorbic Acid / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005231:Fatty Acids, Unsaturated / Q000378:metabolism; D008054:Lipid Peroxides / Q000378:metabolism*; D008081:Liposomes / Q000378:metabolism*; D010713:Phosphatidylcholines / Q000378:metabolism*; D013997:Time Factors; D014810:Vitamin E / Q000494:pharmacology*
D005231:Fatty Acids, Unsaturated; D008054:Lipid Peroxides; D008081:Liposomes; D010713:Phosphatidylcholines; D014810:Vitamin E; D001205:Ascorbic Acid