title: Comparative study on the action of tocopherols and tocotrienols as antioxidant: chemical and physical effects.
abstract: alpha-Tocopherol is known as the most abundant and active form of vitamin E homologues in vivo, but recently the role of other forms of vitamin E has received renewed attention. The antioxidant properties were compared for alpha-, beta-, gamma- and delta-tocopherols and tocotrienols. The following results were obtained: (1). the corresponding tocopherols and tocotrienols exerted the same reactivities toward radicals and the same antioxidant activities against lipid peroxidation in solution and liposomal membranes; (2). tocopherols gave more significant physical effect than tocotrienols on the increase in rigidity at the membrane interior; (3). tocopherols and tocotrienols showed similar mobilities within the membranes, but tocotrienols were more readily transferred between the membranes and incorporated into the membranes than tocopherols; (4). alpha-tocopherol and alpha-tocotrienol, but not the other forms, reduced Cu(II) to give Cu(I) together with alpha-tocopheryl and alpha-tocotrienyl quinones, respectively and exerted prooxidant effect in the oxidation of methyl linoleate in SDS micelles.
authors.affiliation: Human Stress Signal Research Center (HSSRC), National Institute of Advanced Industrial Science and Technology (AIST), Ikeda, Osaka 563-8577, Japan. yoshida-ya@aist.go.jp
authors.forename: Yasukazu
authors.initials: Y
authors.lastname: Yoshida
authors.forename: Etsuo
authors.initials: E
authors.lastname: Niki
authors.forename: Noriko
authors.initials: N
authors.lastname: Noguchi
mesh_terms: D000975:Antioxidants / Q000737:chemistry; D003300:Copper / Q000737:chemistry*; D004134:Dimyristoylphosphatidylcholine / Q000031:analogs & derivatives* / Q000737:chemistry*; D004578:Electron Spin Resonance Spectroscopy; D016166:Free Radical Scavengers / Q000737:chemistry; D008081:Liposomes / Q000737:chemistry*; D008560:Membrane Fluidity; D010084:Oxidation-Reduction; D010713:Phosphatidylcholines / Q000737:chemistry*; D024505:Tocopherols / Q000737:chemistry* / Q000145:classification; D024508:Tocotrienols / Q000737:chemistry* / Q000145:classification
chemical_list: D000975:Antioxidants; D016166:Free Radical Scavengers; D008081:Liposomes; D010713:Phosphatidylcholines; D024508:Tocotrienols; C055402:1-palmitoyl-2-linoleoylphosphatidylcholine; C064744:dimyristoylphosphatidylsulfocholine; D003300:Copper; D024505:Tocopherols; D004134:Dimyristoylphosphatidylcholine