In the present study we characterized the capacity of zinc to protect lipids and proteins from Fe2+-initiated oxidative damage. The effects of zinc on lipid oxidation were investigated in liposomes composed of brain phosphatidylcholine (PC) and phosphatidylserine (PS) at a molar relationship of 60:40 (PC:PS, 60:40). Lipid oxidation was evaluated as the oxidation of cis-parinaric acid or as the formation of 2-thiobarbituric acid-reactive substances (TBARS). Zinc protected liposomes from Fe2+ (2,5-50 μM)-supported lipid oxidation. However, zinc (50 μM) did not prevent the oxidative inactivation of glutamine synthetase and glucose 6-phosphate dehydrogenase when rat brain supernatants were oxidized in the presence of 5 μM Fe2+ and 0.5 mM H2O2. We also studied the interactions of zinc with epicatechin in the prevention of lipid oxidation in liposomes. The simultaneous addition of 0.5 μM epicatechin (EC) and 50 μM zinc increased the protection of liposomes from oxidation compared to that observed in the presence of zinc or EC separately. Zinc (50 μM) also protected liposomes from the stimulatory effect of aluminum on Fe2+-initiated lipid oxidation. Zinc could play an important role as an antioxidant in biological systems, replacing iron and other metals with pro-oxidant activity from binding sites and interacting with other components of the oxidant defense system.
|Original language||English (US)|
|Number of pages||8|
|State||Published - 2000|
- Free radicals
- Lipid peroxidation
ASJC Scopus subject areas
- Agricultural and Biological Sciences(all)