Search results for "lipid peroxidation"
showing 10 items of 300 documents
Stability of the lipid fraction of milk‐based infant formulas during storage
2005
A study is made of the effects of storage (time and temperature) on the lipid fraction of four milk-based adapted infant formulas with basically the same composition, though differing in the iron salt added (lactate or sulfate) and/or the vitamin E source (a-tocopherol or α-tocopherol acetate). Peroxide value, hydroperoxide C 18 percentage and thiobarbituric acid-reactive substance (TBARS) content were used as indicators of lipid peroxidation. Fat contents remained stable throughout storage. Peroxide values increased from the first storage month and were affected by storage time, although they exhibited irregular behavior. Storage time and temperature affected hydroperoxide percentage, whic…
Contribution of vitamin A to the oxidation resistance of human low density lipoproteins.
1995
This study investigated the antioxidant contribution of vitamin A in protecting human low density lipoprotein (LDL) against copper-stimulated oxidation. The presence of small amounts of retinol (0.033 ± 0.012 nmol/mol LDL) and retinyl palmitate (0.036 ± 0.021 nmol/mol LDL) was routinely ascertained in the LDL. A single oral supplementation with 20,000 IU vitamin A caused a two- to three-fold increase of retinol and retinyl palmitate in the LDL isolated 8 h after the supplementation. In comparison to autologous-control LDL, vitamin A-enriched LDL were more resistant to oxidation, as expressed both by a clear delay in the onset of lipid peroxidation and by a reduction of the rate of conjugate…
Oral administration of vitamin C decreases muscle mitochondrial biogenesis and hampers training-induced adaptations in endurance performance
2008
Background Exercise practitioners often take vitamin C supplements because intense muscular contractile activity can result in oxidative stress, as indicated by altered muscle and blood glutathione concentrations and increases in protein, DNA, and lipid peroxidation. There is, however, considerable debate regarding the beneficial health effects of vitamin C supplementation. Objective This study was designed to study the effect of vitamin C on training efficiency in rats and in humans. Design The human study was double-blind and randomized. Fourteen men (27-36 y old) were trained for 8 wk. Five of the men were supplemented daily with an oral dose of 1 g vitamin C. In the animal study, 24 mal…
Antioxidant status and circulating lipids are altered in human gestational diabetes and macrosomia.
2007
Fetuses from mothers with gestational diabetes are at increased risk of developing neonatal macrosomia and oxidative stress. We investigated the modulation of antioxidant status and circulating lipids in gestational diabetic mothers and their macrosomic babies and in healthy age-matched pregnant women and their newborns. The serum antioxidant status was assessed by employing anti-radical resistance kit (KRL; Kirial International SA, Couternon, France) and determining levels of vitamin A, C, and E and the activity of superoxide dismutase (SOD). Circulating serum lipids were quantified, and lipid peroxidation was measured as the concentrations of serum thiobarbituric acid-reactive substances …
[37] Interactions between vitamin A and vitamin E in liposomes and in biological contexts
1999
Publisher Summary This chapter discusses the interactions between vitamin A and vitamin E in liposomes. The chapter reviews several studies carried out by incorporating a variable proportion of all- trans -retinol and α-tocopherol in soybean phosphatidylcholine liposomes. It discusses the antioxidant effectiveness of all- trans - retinol in retinal membranes, whether deprived of endogenous α-tocopherol. In the experiments discussed in the chapter, synergistic effects between all- trans -retinal and α -tocopherol are evident in chemical bilayer as well as in natural membranes. In addition, when all- trans -retinol and α –tocopherol are allowed to act in combination, consumption of both antio…
Antioxidant Activity of Vitamin A within Lipid Environments
1998
New information about deleterious effects of free radicals on cell compartments, and a growing amount of associations between free radicals and various pathological conditions, have produced considerable interest in the biological defense systems against oxidative injury. The antioxidant properties of vitamin A, known for decades (Monaghan and Schmitt, 1932), have been reinvestigated in recent years in chemical as well as in biological systems. Its lipid nature and the localization within the lipophilic compartment of membranes and lipoproteins make vitamin A effective in reducing lipid peroxidation by acting as a chain-breaking antioxidant.
Synergistic Interactions between Vitamin A and Vitamin E against Lipid Peroxidation in Phosphatidylcholine Liposomes
1996
Interactions between alpha-tocopherol and all-trans retinol in suppressing lipid peroxidation were studied in a unilamellar liposomal system of phosphatidylcholine from either egg or soybean, in which peroxidation was initiated by the water-soluble azo initiator 2,2-azobis(2-amidino-propane)hydrochloride and peroxidation was measured as production of conjugated diene hydroperoxides. While all-trans retinol alone was poorly effective, the combination of all-trans retinol with alpha-tocopherol caused an inhibition period far beyond the sum of the inhibition periods observed with individual antioxidants, providing evidence of synergistic interactions. Furthermore, the inhibition rate calculate…
Effect of corn oil and vitamin E on the oxidative status of adipose tissues and liver in rat
2003
Abstract The diet is usually formed of a varying antioxidant and fatty acid content acquired from oils. The purpose of this study was to determine the effects of corn oil-rich diet supplemented or not with vitamin E on oxidative damage and antioxidant status in liver and adipose tissue of rat. Male Wistar rats were fed during 4 weeks with a hyperlipidic diet. The groups fed with hyperlipidic diets showed lower activity levels than the control groups with the exception of superoxide dismutase and glutathione peroxidase in brown adipose tissue. Supplementation of the control group with vitamin E (CE) did not produce any significant changes in the superoxide dismutase and catalase levels, but …
N-3 fatty acids modulate antioxidant status in diabetic rats and their macrosomic offspring.
2006
We investigated the role of dietary n-3 polyunsaturated fatty acids (n-3 PUFA) in the modulation of total antioxidant status in streptozotocin (STZ)-induced diabetic rats and their macrosomic offspring. Female wistar rats, fed on control diet or n-3 PUFA diet, were rendered diabetic by administration of five mild doses of STZ on day 5 and were killed on days 12 and 21 of gestation. The macrosomic (MAC) pups were killed at the age of 60 and 90 days. Lipid peroxidation was measured as the concentrations of plasma thiobarbituric acid reactive substances (TBARS), and the total antioxidant status was determined by measuring (i) plasma oxygen radical absorbance capacity (ORAC), (ii) plasma vitami…
Vitamin A Inhibits Doxorubicin-Induced Membrane Lipid Peroxidation in Rat Tissues in Vivo
1993
The antioxidant activity of vitamin A against lipid peroxidation induced by doxorubicin in rat tissues in vivo was investigated. A single ip injection of doxorubicin (30 mg/kg body wt) markedly raised the level of peroxidated lipids measured as TBARS and conjugated dienes in heart and brain membrane preparations. Other tissues, such as retina and liver, did not show any increase of lipid peroxides over control values. Pretreatment of rats with two daily subcutaneous injections of retinol palmitate (0.25 g/kg body wt), for 2 days, before injecting doxorubicin, inhibited peroxidation of heart and brain membrane lipids. The antioxidant action of vitamin A does not appear to be mediated by enha…