Search results for "ANTIOXIDANTS"
showing 10 items of 827 documents
α-Tocopherol-induced radical scavenging activity in carbon nanotubes for thermo-oxidation resistant ultra-high molecular weight polyethylene-based na…
2014
?-Tocopherol, a natural antioxidant molecule, was physically immobilized on the outer surface of multi-walled carbon nanotubes (CNTs), and the resulting functionalised particles (f-CNTs) were dispersed in ultra-high molecular weight polyethylene aiming at improving its thermo-oxidation resistance. The success of the functionalization was assessed through spectroscopic and thermal analysis, and the influence of the filler on the thermo-oxidative stability of the nanocomposites was investigated through rheological analyses and infrared spectroscopy. We found that the addition of only 1 wt.% of f-CNTs brings about a surprisingly high oxidation resistance, with a five/ten-fold increase of the i…
Antioxidant betalains from cactus pear (Opuntia ficus-indica) inhibit endothelial ICAM-1 expression.
2004
It has been suggested that some pigments would have antioxidant properties and that their presence in dietary constituents would contribute to reduce the risk of oxidative stress–correlated diseases. Among others, inflammatory response depends on redox status and may implicate oxidative stress. Vascular endothelial cells are a direct target of oxidative stress in inflammation. We have tested the impact of the free radical scavenger and antioxidant properties of betalains from the prickle pear in an in vitro model of endothelial cells. Here we show the capacity of betalains to protect endothelium from cytokine- induced redox state alteration, through ICAM-1 inhibition. KEYWORDS: endothelial …
Plasmodium falciparumMalaria: Reduction of Endothelial Cell Apoptosis In Vitro
2005
ABSTRACTOrgan failure inPlasmodium falciparummalaria is associated with neutrophil activation and endothelial damage. This study investigates whether neutrophil-induced endothelial damage involves apoptosis and whether it can be prevented by neutralization of neutrophil secretory products. Endothelial cells from human umbilical veins were coincubated with neutrophils from healthy donors and with sera from eight patients withP. falciparummalaria, three patients withP. vivaxmalaria, and three healthy controls. Endothelial apoptosis was demonstrated by terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling (TUNEL) and annexin V staining. The rate of apoptosis of cells was …
Oxidative stress in vascular disease: causes, defense mechanisms and potential therapies
2007
Endothelial cells control vascular homeostasis by generating paracrine factors that regulate vascular tone, inhibit platelet function, prevent adhesion of leukocytes, and limit proliferation of vascular smooth muscle. The dominant factor responsible for many of those effects is endothelium-derived nitric oxide (NO). Endothelial dysfunction characterized by enhanced inactivation or reduced synthesis of NO, alone or in combination, is seen in conjunction with risk factors for cardiovascular disease. Endothelial dysfunction can promote vasospasm, thrombosis, vascular inflammation, and proliferation of the intima. Vascular oxidative stress and increased production of reactive oxygen species con…
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 …
Zizyphus lotus L. (Desf.) modulates antioxidant activity and human T-cell proliferation
2009
Abstract Background Zizyphus lotus L. (Desf.) also known as Jujube, is a deciduous shrub which belongs to Rhamnaceae family. This plant is used in Algerian traditional medicine for its anti-diabetic, sedative, analgesic, anti-inflammatory and hypoglycaemic activities. In the present study, we determined the concentrations of different vitamins (vitamin A, C and E) and fatty acids in root, stem, leaves, fruit pulp and seed of Zizyphus lotus L. (Desf.) and assessed the effects of their aqueous extracts on antioxidant status and human T-cell proliferation. Methods Aqueous filtrates from different parts, i.e, root, leaf, stem, fruit pulp and seed, of Zizyphus lotus L. (Desf.) were prepared. Vit…
Inhibition of Folic Acid Uptake by Catechins and Tea Extracts in Caco-2 Cells
2006
In this present study it was aimed to determine whether the catechins contained in green tea and the whole extracts of Camellia sinensis (Theaceae) inhibit the uptake of folic acid by Caco-2 cell monolayers. Our results indicate that (-)-epigallocatechin 3-gallate (EGCG) and (-)-epicatechin 3-gallate (ECG) inhibit cellular folic acid uptake with IC50 values of 34.8 micromol/L and 30.8 micromol/L, respectively. Furthermore, green and black tea extracts were also found to inhibit folic acid uptake with IC50 values of approximately 7.5 and 3.6 mg/mL, respectively. According to these results, simultaneous intake of tea and folic acid may inhibit intestinal folic acid absorption. The consequence…
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…