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Antioxidant Molecules (antioxidant + molecule)
Selected AbstractsMelatonin delivery in solid lipid nanoparticles: prevention of cyclosporine A induced cardiac damageJOURNAL OF PINEAL RESEARCH, Issue 3 2009Rita Rezzani Abstract:, Melatonin is a potent antioxidant molecule with a capacity to protect tissues from damage caused by oxidative stress. It reduces cyclosporine A (CsA)-induced cardiotoxicity; this improvement required melatonin's binding to its membrane receptors. This experimental study examined whether melatonin is a useful tool for counteracting CsA-induced apoptosis in the heart of rats. We investigated melatonin's antiapoptotic efficacy in protecting the heart and tested whether this effect was totally dependent on its binding to membrane receptors or also involved radical scavenging. In some animals, solid lipid nanoparticles (SLN) as a melatonin delivery system were used. In one group of rats, melatonin (1 mg/kg/day i.p.) was given concurrently with CsA (15 mg/kg/day s.c.; CsA-MT) for 21 days. In other animals, melatonin loaded in SLN was injected with CsA (CsA-MTSLN). Oxidative stress in heart tissue was estimated using the evaluation of lipid peroxidation and the expression of the isoform of inducible nitric oxide (iNOS). The antiapoptotic effect of melatonin was evaluated using TUNEL staining and Bcl-2 protein family expression. CsA administration produced morphological and biochemical changes in the heart of rats, while melatonin reversed the changes. In particular, since the antiapoptotic melatonin's efficacy is mainly observed when it is loaded in SLN, we suggest that MT1/MT2 pathway is not sufficient for apoptosis antagonism and the additional intracellular effects may be required. Finally, we show that, (i) melatonin significantly reduces CsA cardiotoxicity acting also on apoptotic processes, and (ii) the reduction in CsA-induced cardiotoxicity is mediated mainly by its antioxidant effect. [source] Mice transgenic for exon 1 of the Huntington's disease gene display reduced striatal sensitivity to neurotoxicity induced by dopamine and 6-hydroxydopamineEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 9 2001Ĺsa Petersén Abstract Huntington's disease is an autosomal dominant hereditary neurodegenerative disorder characterized by severe striatal cell loss. Dopamine (DA) has been suggested to play a role in the pathogenesis of the disease. We have previously reported that transgenic mice expressing exon 1 of the human Huntington gene (R6 lines) are resistant to quinolinic acid-induced striatal toxicity. In this study we show that with increasing age, R6/1 and R6/2 mice develop partial resistance to DA- and 6-hydroxydopamine-mediated toxicity in the striatum. Using electron microscopy, we found that the resistance is localized to the cell bodies and not to the neuropil. The reduction of dopamine and cAMP regulated phosphoprotein of a molecular weight of 32 kDa (DARPP-32) in R6/2 mice does not provide the resistance, as DA-induced striatal lesions are not reduced in size in DARPP-32 knockout mice. Neither DA receptor antagonists nor a N -methyl- d -aspartate (NMDA) receptor blocker reduce the size of DA-induced striatal lesions, suggesting that DA toxicity is not dependent upon DA- or NMDA receptor-mediated pathways. Moreover, superoxide dismutase-1 overexpression, monoamine oxidase inhibition and the treatment with the free radical scavenging spin-trap agent phenyl-butyl-tert-nitrone (PBN) also did not block DA toxicity. Levels of the antioxidant molecules, glutathione and ascorbate were not increased in R6/1 mice. Because damage to striatal neurons following intrastriatal injection of 6-hydroxydopamine was also reduced in R6 mice, a yet-to-be identified antioxidant mechanism may provide neuroprotection in these animals. We conclude that striatal neurons of R6 mice develop resistance to DA-induced toxicity with age. [source] Free radicals, antioxidants, and soil organic matter recalcitranceEUROPEAN JOURNAL OF SOIL SCIENCE, Issue 2 2006D. L. Rimmer Summary Highly reactive, and potentially damaging, free radicals are readily generated in our oxygen-rich environment, and are ubiquitous in biological systems. However, plants and animals have evolved protection against them with a range of antioxidant molecules, such as vitamins C and E, many of which are phenolic compounds. These stop the destructive chain reaction of free radical formation by being transformed into unreactive, stable free radicals. The biodegradation of food involves oxidation by free radicals, and is retarded by antioxidants. Similarly, the biodegradation of plant residues in soils involves free radicals; so the questions arise: (i) do soils have antioxidants, and (ii) what function might they have? The evidence suggests that they probably do have antioxidants. First, plant and animal remains added to soils will contain antioxidants. These are likely to persist for a time, particularly tannins, which are polyphenolic compounds with known antioxidant properties and which are relatively resistant to degradation. Second, studies using electron spin resonance spectroscopy have shown that humic materials contain stable semiquinone free radicals, and that their concentration increases as humification progresses. These semiquinone species are most likely to be derived from the reaction of phenolic compounds with reactive radicals. If this is the case, the phenolics are acting as antioxidants, because they are scavenging the reactive free radicals and terminating the oxidative chain reaction responsible for soil organic matter (SOM) degradation. Thus the soil's antioxidant capacity could control the rate of breakdown of organic matter in the more labile pools and could provide a chemical mechanism for the recalcitrance of SOM. Current available evidence for the nature of the recalcitrant pool in SOM is discussed in the light of this hypothesis, and the experimental approaches necessary for testing it are outlined. [source] Characterization of a new tyrosinase from Pycnoporus species with high potential for food technological applicationsJOURNAL OF APPLIED MICROBIOLOGY, Issue 2 2005S. Halaouli Abstract Aims:, Tyrosinase production by Pycnoporus cinnabarinus and Pycnoporus sanguineus was screened among 20 strains originating from various geographical areas, particularly from tropical environments. The tyrosinase from the most efficient strain was purified and characterized and tested for food additive applications. Methods and Results:, Monophenolase and diphenolase activities of tyrosinase were measured from cell lysate from the 20 Pycnoporus strains, for 8,10 days of cultivation. The strain P. sanguineus CBS 614.73 showed the highest productivity (45·4 and 163·6 U g,1 protein per day for monophenolase and diphenolase respectively). P. sanguineus CBS 614.73 tyrosinase was purified from concentrated cell lysate, anion-exchange, size-exclusion and hydroxyapatite chromatography, with a final yield of 2% and a purification factor of 35,38. The pure enzyme was a monomere with a molecular mass of 45 kDa and it showed four isoforms or isoenzymes with pI between 4·5,5. No N-glycosylation was found. The N-terminal amino acid sequence was IVTGPVGGQTEGAPAPNR. The enzyme was shown to be almost fully active in a pH range of 6,7, in a large temperature range (30,70°C), and was stable below 60°C. The main kinetic constants were determined. The tyrosinase was able to convert p -tyrosol and p -coumaric acid into hydroxytyrosol and caffeic acid, respectively, and it could also catalyse the cross-linking formation of a model protein. Conclusions:, Among the genus Pycnoporus, known for the production of laccase, the strain P. sanguineus CBS 614.73 was shown to produce one other phenoloxidase, a new monomeric tyrosinase with a specific activity of 30 and 84 U mg,1 protein for monophenolase and diphenolase respectively. Significance and Impact of the Study:, This study identified P. sanguineus CBS 614.73 as a potential producer of a tyrosinase which demonstrated effectiveness in the synthesis of antioxidant molecules and in protein cross-linking. [source] Oxidative status in iron-deficiency anemiaJOURNAL OF CLINICAL LABORATORY ANALYSIS, Issue 5 2009Jong-Ha Yoo Abstract Oxidative stress is an imbalance between free radicals and antioxidant molecules that can play an important role in the pathogenesis of iron-deficiency anemia (IDA). The aim of this study was to investigate oxidative status in patients with IDA and alteration of oxidative status after iron treatment. Thirty-three female patients with IDA and 25 healthy controls were included in this study. Oxidant and total antioxidant capacity were determined using free oxygen radicals test and free oxygen radicals defence (Form CR 3000, Callegari, Parma, Italy). Catalase activity was measured by spectrophotometer using a commercially available kit (Bioxytech Catalase-520, OxisResearch, Portland, OR). Oxidant activity in patients with IDA was significantly higher than controls (P<0.05), while total antioxidant and catalase activity were significantly lower (P<0.05). After treatment, oxidant, antioxidant, and catalase activity reached the levels of the control group, and no significant differences were observed among groups (P>0.05). In conclusion, our data indicate that blood reactive oxygen species was lower and total antioxidant and catalase activity were higher after rather than before treatment in patients with IDA. The results of our study support the higher oxidative stress hypothesis in IDA; however, due to the limited number of cases included, more studies may be required to confirm the results. J. Clin. Lab. Anal. 23:319,323, 2009. © 2009 Wiley-Liss, Inc. [source] CHANGES IN MAJOR ANTIOXIDANT COMPOUNDS DURING AGING OF TRADITIONAL BALSAMIC VINEGARJOURNAL OF FOOD BIOCHEMISTRY, Issue 1 2010ELENA VERZELLONI ABSTRACT Traditional balsamic vinegar (TBV) shows antioxidant capacity that increases passing from cask 5, containing the youngest vinegar, to cask 1 containing the oldest vinegar. This increase in antioxidant capacity is a consequence of both the concentration of compounds already present and of new antioxidants formation and is positively related to the increase in the polyphenolic content and in the Maillard reaction/caramellization products. During TBV aging, some reactions involving flavonoids and tannins take place. Tannins can undergo acid-catalyzed cleavage of their interflavonoid bonds with subsequent condensation of other flavonoid molecules. In addition, the low pH, the decrease of the water content and the presence of aldehydes, may promote flavonoids polycondensation. These reactions explain the observed increase in polymeric phenolic compounds and the decrease in monomeric flavonoids. During TBV aging an increase in the browning index is observed as a consequence of the polycondensation reactions of flavonoids and of brown melanoidins accumulation. PRACTICAL APPLICATIONS Traditional balsamic vinegar is a potentially healthy seasoning with high antioxidant capacity that increases during the aging resulting in a product with a strong antioxidant capacity and rich in phenolic compounds such as phenolic acids, monomeric catechins, flavonols and tannins. It also contains other antioxidants such as melanoidins derived from the Maillard and caramelization reaction that occur during must boiling and traditional balsamic vinegar aging. Independently of their bioavailability, traditional balsamic vinegar can contribute to supply antioxidant molecules that play an important role in protecting the gastrointestinal tract itself against peroxidation, thereby limiting the formation of detrimental lipid degradation products. [source] A Nonfibrillar Form of the Fusogenic Prion Protein Fragment [118-135] Induces Apoptotic Cell Death in Rat Cortical NeuronsJOURNAL OF NEUROCHEMISTRY, Issue 6 2000Thierry Pillot Abstract: Neuronal loss is a salient feature of prion diseases.However, its cause and mechanism, particularly its relationship with theaccumulation and precipitation of the pathogenic, protease-resistant isoformPrPSc of the cellular prion protein PrPC, are still anenigma. Several studies suggest that neuronal loss could occur through aprocess of programmed cell death, which is consistent with the lack ofinflammation in these conditions. By analogy with the pathological eventsoccurring during the development of Alzheimer's disease, controversies stillexist regarding the relationship between amyloidogenesis, prion aggregation,and neuronal loss. We recently demonstrated that a prion protein fragment(118-135) displayed membrane-destabilizing properties and was able to induce,in a nonfibrillar form, the fusion of unilamellar liposomes. To unravel themechanism of prion protein neurotoxicity, we characterize the effects of thehuman Pr[118-135] peptide on rat cortical neurons. We demonstrate that lowconcentrations of the Pr[118-135] peptide, in a nonfibrillar form, induce atime- and dose- dependent apoptotic cell death, including caspase activation,DNA condensation, and fragmentation. This toxicity might involve oxidativestress, because antioxidant molecules, such as probucol and propyl gallate,protect neurons against prion peptide toxicity. By contrast, a nonfusogenicvariant Pr[118-135, 0°] peptide, which displays the same amino acidcomposition but several amino acid permutations, is not toxic to corticalneurons, which emphasizes the critical role of the fusogenic properties of theprion peptide in its neurotoxicity. Taken together, our results suggest thatthe interaction between the Pr[118-135] peptide and the plasma membrane ofneurons might represent an early event in a cascade leading toneurodegeneration. [source] Antioxidant nutritional quality of tomatoMOLECULAR NUTRITION & FOOD RESEARCH (FORMERLY NAHRUNG/FOOD), Issue 5 2007Luigi Frusciante Abstract Regular consumption of tomatoes has been associated with decreased risk of chronic degenerative diseases. Epidemiological findings confirm the observed health effects are due to the presence of different antioxidant molecules such as carotenoids, particularly lycopene, ascorbic acid, vitamin E and phenol compounds, particularly flavonoids. In this work, eight components contributing to the healthy quality of tomato (i. e. lycopene, ,-carotene, other carotenoids, flavonoids, phenolic acids, vitamins C and E, dry residue) were studied in the framework of breeding programs aiming to develop nutritional superior genotypes. Twelve tomato advanced breeding lines and six open pollinated cultivars were grown in strictly controlled conditions and analysed for their content of antioxidants. Among the 18 genotypes analysed, 10 showed a high level of total carotenoids, 6 high level of ,-carotene, 9 high lycopene levels, 15 high flavonoids and 2 relevant concentration of vitamin E. Based on such data and on a literature survey on tomato composition, an index, called index of antioxidant nutritional quality (IQUAN), was proposed as a tool to address the breeding programs in selecting tomato genotypes with antioxidant nutritional qualities. [source] Free radical scavenging, enzyme inhibitory constituents from antidiabetic Ayurvedic medicinal plant Hydnocarpus wightiana BlumePHYTOTHERAPY RESEARCH, Issue 4 2005S. Venkat Reddy Abstract Hydnocarpus wightiana is advocated in traditional Indian medicine to possess strong antidiabetic activity. In the course of identifying bioactive fractions from Indian medicinal plants we observed that acetone extract of the seed hulls of H. wightiana possess strong free radicals (DPPH and ABTS) scavenging, , -glucosidase and moderate N-acetyl- , -D-glucosaminidase inhibitory activities. Further fractionation of the extract led to the isolation of hydnocarpin, luteolin and isohydnocarpin in substantial yields. All the compounds showed strong ABTS scavenging property. However, only luteolin could display strong DPPH scavenging activity. Furthermore, all the three compounds also showed varying degrees of , -glucosidase and N-acetyl- , -D-glucosaminidase inhibitory activity, luteolin being the superior. The kinetics of , -glucosidase inhibition by these compounds showed that acetone extract inhibits the enzyme in competitive manner however, luteolin and isohydnocarpin showed mixed-type inhibition. This is the first report assigning hydnocarpin and isohydnocarpin free radical scavenging, , -glucosidase and N-acetyl- , -D-glucosaminidase inhibitory properties and luteolin as N-acetyl- , -D-glucosaminidase inhibitor. This study suggests that presence of amphiphilic antioxidant molecules along with enzyme inhibitory activities in the acetone extract of H. wightiana seed hulls may be responsible for the antidiabetic properties as advocated in traditional medicine. Copyright © 2005 John Wiley & Sons, Ltd. [source] Photo-stabilization of EPDM,clay nanocomposites: effect of antioxidant on the preparation and durability,POLYMERS FOR ADVANCED TECHNOLOGIES, Issue 11 2007Sunil P. Lonkar Abstract The present study is to examine the photo-stabilization effect of an antioxidant on the photo-oxidation of ethylene-propylene-diene monomer (EPDM),clay nanocomposites. During the preparation of EPDM,clay nanocomposites via melt processing antioxidants are usually incorporated along with clay, which allows phenolic antioxidant molecules to get adsorbed onto acidic clay platelets and their interaction with metallic impurities reduces the stabilizing efficiency of the antioxidant. The nanocomposites were obtained by solution dispersion followed by melt compounding of EPDM and organophilic montmorillonite (OMMT). The samples were characterized by conventional tools such as X-ray diffraction (XRD), Fourier Transform Infra Red (FT-IR) spectroscopy, and thermo-gravimetric analysis (TGA). It was found, upon photo-irradiation (,,>,290,nm) studies by following the changes in functional groups and surface morphology, that photo-degradation was lowered by the antioxidant and the efficiency of the antioxidant could be improved by initial incorporation of antioxidant in the EPDM matrix. In EPDM,clay nanocomposites, a stabilizing activity of the antioxidant was observed above some threshold concentration of the antioxidant. The relationship between the nanoclay reinforcement and stabilizing efficiency in terms of photo-oxidation and surface morphology for their applicability are discussed. The methodology adopted for this study is also justified through our observation. Copyright © 2007 John Wiley & Sons, Ltd. [source] | |||||||||||||