The effects of alpha-tocopherol on site-specific lipid peroxidation induced by iron in charged micelles.
alpha-Tocopherol inhibited H2O2-Fe2+-induced lipid peroxidation of linoleic acid (LA) by scavenging OH radicals in tetradecyltrimethylammonium bromide (TTAB) micelles. The inhibiting ability of alpha-tocopherol was much greater than that of OH-radical scavengers mannitol and t-butanol. In contrast, alpha-tocopherol enhanced linoleic acid hydroperoxide (LOOH)-Fe2+-induced lipid peroxidation through regeneration of Fe2+ in sodium dodecyl sulfate (SDS) micelles containing LA. alpha-Tocopherol was oxidized by Fenton's reagent (FeSO4 + H2O2) at a higher rate in SDS micelles than in TTAB micelles. The likely oxidants were OH radicals in the former and Fe3+ in the latter. Both reagents formed in the Fenton reaction. Ferrous ion catalyzed in a dose-dependent manner the decomposition of LOOH and conjugated diene compounds in SDS but not in TTAB micelles. alpha-Tocopherol and Fe3+ individually had no effect on the decomposition of LOOH, but together were quite effective. The rate of the decomposition was a function of the concentration of alpha-tocopherol. The mechanism of "site-specific" antioxidant action of alpha-tocopherol in charged micelles is discussed.
Fukuzawa
K
K
Faculty of Pharmaceutical Sciences, Tokushima University, Japan.
Kishikawa
K
K
Tadokoro
T
T
Tokumura
A
A
Tsukatani
H
H
Gebicki
J M
JM
D003102:Colloids; D005296:Ferrous Compounds / Q000494:pharmacology*; D006861:Hydrogen Peroxide / Q000494:pharmacology; D007202:Indicators and Reagents; D007501:Iron / Q000494:pharmacology; D008041:Linoleic Acids / Q000494:pharmacology; D008054:Lipid Peroxides / Q000378:metabolism* / Q000494:pharmacology; D008823:Micelles; D010101:Oxygen Consumption / Q000187:drug effects; D000644:Quaternary Ammonium Compounds; D012967:Sodium Dodecyl Sulfate; D014810:Vitamin E / Q000494:pharmacology*
D003102:Colloids; C045076:Fenton's reagent; D005296:Ferrous Compounds; D007202:Indicators and Reagents; D008041:Linoleic Acids; D008054:Lipid Peroxides; D008823:Micelles; D000644:Quaternary Ammonium Compounds; D014810:Vitamin E; C008285:linoleic acid hydroperoxide; D012967:Sodium Dodecyl Sulfate; D006861:Hydrogen Peroxide; D007501:Iron