Search results for "Oxidation-Reduction"
showing 10 items of 689 documents
Antioxidant effects of resveratrol in cardiovascular, cerebral and metabolic diseases.
2013
Resveratrol-a natural polyphenolic compound-was first discovered in the 1940s. Although initially used for cancer therapy, it has shown beneficial effects against most cardiovascular and cerebrovascular diseases. A large part of these effects are related to its antioxidant properties. Here we review: (a) the sources, the metabolism, and the bioavailability of resveratrol; (b) the ability of resveratrol to modulate redox signalling and to interact with multiple molecular targets of diverse intracellular pathways; (c) its protective effects against oxidative damage in cardio-cerebro-vascular districts and metabolic disorders such as diabetes; and (d) the evidence for its efficacy and toxicity…
Direct and indirect antioxidant properties of α-lipoic acid and therapeutic potential.
2012
International audience; Diabetes has emerged as a major threat to worldwide health. The exact mechanisms underlying the disease are unknown; however, there is growing evidence that the excess generation of reactive oxygen species (ROS) associated with hyperglycemia, causes oxidative stress in a variety of tissues. In this context, various natural compounds with pleiotropic actions like lipoic acid (LA) are of interest, especially in metabolic diseases such as diabetes. LA, either as a dietary supplement or a therapeutic agent, modulates redox potential because of its ability to match the redox status between different subcellular compartments as well as extracellularly. Both the oxidized (d…
Novel imine antioxidants at low nanomolar concentrations protect dopaminergic cells from oxidative neurotoxicity.
2009
Strong evidence indicates that oxidative stress may be causally involved in the pathogenesis of Parkinson's disease. We have employed human dopaminergic neuroblastoma cells and rat primary mesencephalic neurons to assess the protective potential of three novel bisarylimine antioxidants on dopaminergic cell death induced by complex I inhibition or glutathione depletion. We have found that exceptionally low concentrations (EC(50) values approximately 20 nM) of these compounds (iminostilbene, phenothiazine, and phenoxazine) exhibited strong protective effects against the toxicities of MPP(+), rotenone, and l-buthionine sulfoximine. Investigating intracellular glutathione levels, it was found t…
Antioxidant Activity of Sicilian Pistachio (Pistacia veraL. Var. Bronte) Nut Extract and Its Bioactive Components
2007
Pistacia vera L. is the only species of Pistacia genus producing edible nuts. This paper investigates the antioxidant potential of a Sicilian variety of pistachio nut by chemical as well as biological assays and measured antioxidant vitamins and a number of antioxidant polyphenols in either the hydrophilic and/or the lipophilic nut extract. In accordance with the majority of foods, the total antioxidant activity, measured as a TAA test, was much higher (50-fold) in the hydrophilic than in the lipophilic extract. Substantial amounts of total phenols were measured. The hydrophilic extract inhibited dose-dependently both the metal-dependent and -independent lipid oxidation of bovine liver micr…
Betacyanins as phenol antioxidants. Chemistry and mechanistic aspects of the lipoperoxyl radical-scavenging activity in solution and liposomes.
2009
Reaction kinetics of betanin and its aglycone betanidin towards peroxyl radicals generated from the azo-initiated oxidation of methyl linoleate in methanol, and of a heterogeneous aqueous/soybean phosphatidylcholine liposomal system, were studied by monitoring formation of linoleic acid hydroperoxides and consumption of the pigments. Betanin was a weak retarder in methanol, and an effective chain breaking antioxidant in the liposomal model, indicating that kinetic solvent effects and partition in lipid bilayers may affect its activity. Betanidin behaved as a chain terminating antioxidant in both models. Kinetic parameters characterizing peroxyl radical-scavenging activity showed that betani…
Betanin inhibits the myeloperoxidase/nitrite-induced oxidation of human low-density lipoproteins
2007
Production of nitrogen dioxide by the activity of myeloperoxidase (MPO) in the presence of nitrite is now considered a key step in the pathophysiology of low-density lipoprotein (LDL) oxidation. This study shows that betanin, a phytochemical of the betalain class, inhibits the production of lipid hydroperoxides in human LDL submitted to a MPO/nitrite-induced oxidation. Kinetic measurements including time-course of particle oxidation and betanin consumption, either in the presence or in the absence of nitrite, suggest that the antioxidant effect is possibly the result of various actions. Betanin scavenges the initiator radical nitrogen dioxide and can also act as a lipoperoxyl radical-scaven…
Low and very low density lipoprotein composition and resistance to copper-induced oxidation are not notably modified in smokers.
1997
To study whether tobacco use was associated with oxidative phenomena affecting lipoproteins, we estimated susceptibility of LDL and VLDL to an in vitro copper-mediated oxidation, and measured serum autoantibody titers against oxidized LDL in 45 middle-age healthy nonsmokers, 35 smokers and 37 ex-smokers of both sexes, taking into account the detailed lipid composition of the lipoproteins. VLDL from female smokers had higher triglyceride, phospholipid, apolipoprotein E and alpha-tocopherol content and showed a higher rate of copper-induced oxidation in comparison with those from nonsmokers (P < or = 0.05) whereas the relative composition of these particles in saturated, mono- or poly-unsatur…
Increased Atherosclerotic Lesions in ApoE Mice With Plasma Phospholipid Transfer Protein Overexpression
2003
Objective— Plasma phospholipid transfer protein (PLTP) is involved in the metabolism of HDL and apolipoprotein B (apoB)-containing lipoproteins. Atherosclerosis susceptibility is decreased in mice with PLTP deficiency that is associated with decreased liver production of apoB-containing lipoproteins and increase in their antioxidant. To investigate additionally the effect of PLTP on the development of atherosclerosis, we overexpressed PLTP in mice. Methods and Results— PLTP was overexpressed in apoE knockout mice using an adenovirus-associated virus (AAV)-mediated system. Plasma PLTP activity was 1.3- to 2-fold higher in mice injected with AAV-PLTP than in mice injected with control AAV-GF…
Deficiency of glutathione peroxidase-1 accelerates the progression of atherosclerosis in apolipoprotein E-deficient mice.
2007
Background— We have recently demonstrated that activity of red blood cell glutathione peroxidase-1 is inversely associated with the risk of cardiovascular events in patients with coronary artery disease. The present study analyzed the effect of glutathione peroxidase-1 deficiency on atherogenesis in the apolipoprotein E-deficient mouse. Methods and Results— Female apolipoprotein E-deficient mice with and without glutathione peroxidase-1 deficiency were placed on a Western-type diet for another 6, 12, or 24 weeks. After 24 weeks on Western-type diet, double-knockout mice (GPx-1 −/− ApoE −/− ) developed significantly more atherosclerosis than control apolipoprotein E-deficient mice. Moreover…
Opposite vascular activity of (R)-apomorphine and its oxidised derivatives. Endothelium-dependent vasoconstriction induced by the auto-oxidation meta…
2003
We have synthetised a series of oxidised apomorphine derivatives (orto and para quinones 2-5), in order to analyse their vascular activity. We have performed radioligand binding assays on rat cortical membranes and functional studies on rat aortic rings. Instead the relaxant activity exhibited by (R)-apomorphine, o-quinones 2, 4, show contractile activity dependent on endothelium in rat aortic rings. Compound 2, the main metabolite of (R)-apomorphine auto-oxidation, was the product which showed enhanced contractile activity by a complex mechanism related to activation of Ca(2+) channels through release and/or inhibition of endothelial factors. Moreover, this compound disrupts the endothelia…