Thiopalmitic acid-mediated Fe(III)-nitrilotriacetate reduction and lipid peroxidation.
The mechanism of the antioxidant action of thiopalmitic acid (SH-Pal) was examined in an in vitro system measuring ferric (Fe(III)-nitrilotriacetate (NTA)- and Fe(III)-NTA/ascorbic acid (AsA)-induced lipid peroxidation of rat liver phospholipid liposomes and microsomes. The extent of lipid peroxidation was determined by measuring thiobarbituric acid reactive substances (TBARS). SH-Pal and glutathione (GSH) scarcely stimulated the Fe(III)-NTA-induced lipid peroxidation in contrast with the mode of action, being similar to those produced by reducing-agent antioxidants such as cysteine and AsA. SH-Pal reduced iron similar to the action produced by AsA and cysteine, but not that of GSH under the same conditions. Also, the reduction of iron by SH-Pal did not exhibit a pH dependency. Similarly, microsomal lipid peroxidation and oxygen consumption induced by Fe(III)-NTA/AsA were inhibited by the addition of SH-Pal in a time and dose dependent fashion, but GSH and cysteine exhibited a lower protective action. Time course studies on TBARS formation and oxygen consumption indicated the ability of SH-Pal to inhibit initiation and propagation reactions. Moreover, the microsomal lipid peroxidation induced by Cumene hydroperoxide (CumOOH) was progressively suppressed by the addition of increasing amounts of SH-Pal. These findings suggest that the antioxidant action of SH-Pal is partly due to complete reduction of iron at a faster rate and inhibition of oxygen consumption during the progress of the peroxidation. Further, SH-Pal has a protective action against free radical damage by hydroperoxy radical.
Tanaka
M
M
Showa College of Pharmaceutical Sciences, Tokyo, Japan.
Takada
K
K
Higuchi
T
T
Nakagawa
M
M
D000818:Animals; D000975:Antioxidants; D001205:Ascorbic Acid; D005290:Ferric Compounds / Q000737:chemistry*; D005978:Glutathione; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D015227:Lipid Peroxidation; D008081:Liposomes / Q000737:chemistry; D008297:Male; D008862:Microsomes, Liver / Q000737:chemistry; D009571:Nitrilotriacetic Acid / Q000031:analogs & derivatives* / Q000737:chemistry; D010101:Oxygen Consumption; D010169:Palmitic Acids; D010743:Phospholipids / Q000737:chemistry*; D051381:Rats; D017208:Rats, Wistar; D017392:Thiobarbituric Acid Reactive Substances / Q000032:analysis
D000975:Antioxidants; D005290:Ferric Compounds; D008081:Liposomes; D010169:Palmitic Acids; D010743:Phospholipids; D017392:Thiobarbituric Acid Reactive Substances; C091863:thiopalmitic acid; D005978:Glutathione; D009571:Nitrilotriacetic Acid; D001205:Ascorbic Acid; C020326:ferric nitrilotriacetate