Search results for "Peroxidation"
showing 10 items of 308 documents
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…
Oxidative markers in children with severe obesity following low-calorie diets supplemented with mandarin juice
2010
Aim: To evaluate the effect of supplementing a hypocaloric diet with mandarin juice, a food with a high content of antioxidants (vitamin C, flavonoids and carotenoids), on biomarkers of oxidant/antioxidant status of severe obese children. Methods: Forty obese children were randomized into two groups pair-wise in a 4-week controlled intervention study. Both groups followed a hypocaloric diet. One group received additionally a supplementation of 500 mL of 100% mandarin juice daily. Clinical data, anthropometry, dietary intake and fasting blood samples were collected at baseline and after the intervention. Lipid peroxidation was assessed by circulating levels of malondialdehyde, and protein …
Natural Triterpenoids as Anti-Inflammatory Agents
2000
Abstract This chapter reviews the natural triterpenes with anti-inflammatory activity, including the traditional ones and the new compounds isolated over the last six years. Triterpenes are widely distributed in plants, and in many cases are the principles responsible for their anti-inflammatory effects. Many of these compounds are active in different in vivo experimental models such as hind paw edema induced by carrageenan, serotonin and phospholipase A2; ear edema induced by phorbol and daphnane esters, ethylphenylpropiolate, arachidonic acid and capsaicin; adjuvant arthritis and experimental models of allergy. Other effects have been studied in vitro, and some triterpenes are active agai…
Ischämietoleranz der Rattenleber durch alpha-Liponsäure
2003
Ischemia reperfusion injury (IRI) represents a major clinical problem in liver resection and transplantation. The present work investigated the potential of α-lipoic-acid (LA), a well established drug in the therapy of diabetes, to reduce IRI of the rat liver in vivo. Two groups were chosen: one group with injection of 500 μmol α-lipoic acid 15 min before clamping of the left and median liver lobes for 90 min, the other with injection of NaCl 0,9%. Reperfusion was carried out for 1 h and 7 days. The results showed that a-lipoic acid reduced IRI. LDH, α-GST and lipid peroxidation were significantly decreased in the LA-group after 1 h reperfusion indicating less cell death during reperfusion.…
Peroxydation in vivo et in vitro des acides gras polyinsaturés
2007
It is well admitted that polyunsaturated fatty acids are the most sensitive fatty acids to oxidative damage because of their high number of double bonds. This concept could not be confirmed by in vitro, animal, or human studies since unexpected or even contradictory results were obtained. The explanation of that is probably related to the methods evaluating lipid peroxidation whose relevance is not always established, but especially to movements of polyunsaturated fatty acids within lipoproteins that results in their protection. This short review aims to discuss the main results related to this topic.
4-hydroxynonenal inhibits glutathione peroxidase: protection by glutathione
1999
Abstract 4-Hydroxy-2,3-trans-nonenal, a lipid peroxidation product, inhibits glutathione peroxidase in a concentration-dependent manner. The concentration providing 50% inhibition is 0.12 mM. This inhibition can be almost completely (89%) prevented by 1 mM glutathione added to the incubation mixture 30 min before 4-hydroxy-2,3-trans-nonenal or 2,3-trans-nonenal, but not by other thiol-containing antioxidants such as 0.5 mM dithiothreitol or β-mercaptoethanol. Again the addition of 1 mM glutathione, and not of 0.5 mM dithiothreitol or β-mercaptoethanol, to the enzyme 30 min after incubation with 4-hydroxy-2,3-trans-nonenal restores activity to the same extent as does the preincubation with G…