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Radical Scavengers (radical + scavenger)
Kinds of Radical Scavengers Selected AbstractsComparison of xanthine oxidase-inhibiting and free radical-scavenging activities between plant adaptogens of Eleutherococcus senticosus and Rhodiola roseaDRUG DEVELOPMENT RESEARCH, Issue 4 2010Chi-Ting Horng Abstract The present study employed 2,2-diphenyl-l-picrylhydrazyl (DPPH) radical-scavenging and xanthine,xanthine oxidase (XO) assays to compare the antioxidant capacity between two plant adaptogens, Eleutherococcus senticosus (Araliaceae) and Rhodiola rosea (Crassulaceae). The IC50 value for XO activity for Rhodiola was 355.4,µg/ml, while that for Eleutherococcus was >1,000,µg/ml. Eleutherococcus inhibited DPPH generation by 58.3±2.8% at 1,000,µg/ml, whereas Rhodiola inhibited DPPH radical by 91.1±2.6% at the same concentration. The results suggested that Rhodiola inhibited not only XO but also served as a potent radical scavenger. Rhodiola has potential as a natural source of antioxidants. Drug Dev Res 71:249,252, 2010. © 2010 Wiley-Liss, Inc. [source] Effect of dopamine on rat diaphragm apoptosis and muscle performanceEXPERIMENTAL PHYSIOLOGY, Issue 4 2006Janet D. Pierce The purpose of this study was to determine whether dopamine (DA) decreases diaphragm apoptosis and attenuates the decline in diaphragmatic contractile performance associated with repetitive isometric contraction using an in vitro diaphragm preparation. Strenuous diaphragm contractions produce free radicals and muscle apoptosis. Dopamine is a free radical scavenger and, at higher concentrations, increases muscle contractility by simulating ,2 -adrenoreceptors. A total of 47 male Sprague,Dawley rats weighing 330,450 g were used in a prospective, randomized, controlled in vitro study. Following animal anaesthetization, diaphragms were excised, and muscle strips prepared and placed in a temperature-controlled isolated tissue bath containing Krebs,Ringer solution (KR) or KR plus 100 ,m DA. The solutions were equilibrated with oxygen (O2) at 10, 21 or 95% and 5% carbon dioxide, with the balance being nitrogen. Diaphragm isometric twitch and subtetanic contractions were measured intermittently over 65 min. The diaphragms were then removed and, using a nuclear differential dye uptake method, the percentages of normal, apoptotic and necrotic nuclei were determined using fluorescent microscopy. There were significantly fewer apoptotic nuclei in the DA group diaphragms than in the KR-only group diaphragms in 10 and 21% O2 following either twitch or subtetanic contractions. Dopamine at 100 ,m produced only modest increases in muscle performance in both 10 and 21% O2. The attenuation of apoptosis by DA was markedly greater than the effect of DA on muscle performance. Dopamine decreased diaphragmatic apoptosis, perhaps by preventing the activation of intricate apoptotic pathways, stimulating antiapoptotic mechanisms and/or scavenging free radicals. [source] Temperature-dependent kinetic study for ozonolysis of selected tropospheric alkenesINTERNATIONAL JOURNAL OF CHEMICAL KINETICS, Issue 12 2002Elena V. Avzianova Ozonolysis reactions of alkenes are suggested to play major roles in the chemistry of the troposphere. Rate constants for the gas-phase reactions of O3 with a series of alkenes were determined using relative rate technique based on GC/FID measurements of alkene decays. Experiments were carried out in air over the temperature range of 278,353 K at an atmospheric pressure of 760 Torr. An excess of 1,3,5-trimethylbenzene was used as a HO radical scavenger in all experiments. Arrhenius parameters were calculated for ozonolysis of 1-butene, 1-pentene, 1-hexene, 1-heptene, 2-methyl-1-butene, isobutene, trans -2-butene, trans -2-pentene, cis -2-pentene, trans -2-hexene, cis -2-hexene, 3-chloropropene, 1,1-dichloroethene, and isoprene from temperature-dependent studies of the rate constants. The rate constants obtained in this study are compared with previous literature data. A good linear correlation between the logarithms of the rate constants and calculated HOMO energies of selected alkenes is observed. However, no clear correlation could have been drawn for chlorinated substituted alkenes. © 2002 Wiley Periodicals, Inc. Int J Chem Kinet 34: 678,684, 2002 [source] Melatonin: therapeutic and clinical utilizationINTERNATIONAL JOURNAL OF CLINICAL PRACTICE, Issue 5 2007A. Altun Summary Melatonin, acting through melatonin receptors, is involved in numerous physiological processes including circadian entrainment, blood pressure regulation, oncogenesis, retinal physiology, seasonal reproduction, ovarian physiology, immune function and most recently in inducing osteoblast differentiation. Moreover, melatonin was proved to be a potent-free radical scavenger and a broad-spectrum antioxidant. More research is required into the effects of therapeutically modulating the melatoninergic system on circadian haemodynamics and rhythm under varying physiopathological conditions and the possible impact on morbidity and mortality in humans. [source] Advanced oxidation processes for destruction of cyanide from thermoelectric power station waste watersJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 2 2004José M Monteagudo Abstract Several advanced oxidation processes for the destruction of cyanide contained in waste waters from thermoelectric power stations of combined-cycle were studied. Thus, oxidation processes involving ozonation at basic pH, ozone/hydrogen peroxide, ozone/ultraviolet radiation and ozone/hydrogen peroxide/ultraviolet radiation have been carried out in a semi-batch reactor. All these methods showed that total cyanide can be successfully degraded but with different reaction rates, and the decrease in the total cyanide concentration can be described by pseudo-first order kinetics. The influence of pH and initial concentration of hydrogen peroxide was studied to find the optimal conditions of the oxidation process. Experimental results of the single ozone treatment indicated that total cyanide is destroyed more rapidly at higher pH (12), while ozonation combined with H2O2 and/or UV is faster at pH 9.5. The optimum concentration of H2O2 was 20.58 × 10,2M because an excess of peroxide decreases the reaction rate, acting as a radical scavenger. The total cyanide degradation rate in the O3/H2O2(20.58 × 10,2M) treatment was the highest among all the combinations studied. However, COD reduction, in the processes using UV radiation such as O3/UV or O3/H2O2/UV was about 75%, while in the processes with H2O2 and/or O3/H2O2 was lower than 57% and was insignificant, when using ozone alone. Copyright © 2003 Society of Chemical Industry [source] ANTHOCYANIN INTERACTIONS WITH DNA: INTERCALATION, TOPOISOMERASE I INHIBITION AND OXIDATIVE REACTIONSJOURNAL OF FOOD BIOCHEMISTRY, Issue 5 2008MICHAEL R. WEBB ABSTRACT Anthocyanins and their aglycone anthocyanidins are pigmented flavonoids found in significant amounts in many commonly consumed foods. They exhibit a complex chemistry in aqueous solution, which makes it difficult to study their chemistry under physiologic conditions. Here we used a gel electrophoresis assay employing supercoiled DNA plasmid to examine the ability of these compounds (1) to intercalate DNA; (2) to inhibit human topoisomerase I through both inhibition of plasmid relaxation activity (catalytic inhibition) and stabilization of the cleavable DNA,topoisomerase complex (poisoning); and (3) to inhibit or enhance oxidative single-strand DNA nicking. We found no evidence of DNA intercalation by anthocyan(id)ins in the physiologic pH range for any of the compounds used in this study , cyanidin chloride, cyanidin 3- O -glucoside, cyanidin 3,5- O -diglucoside, malvidin 3- O -glucoside and luteolinidin chloride. The anthocyanins inhibited topoisomerase relaxation activity only at high concentrations (>50 µM), and we could find no evidence of topoisomerase I cleavable complex stabilization by these compounds. However, we observed that all of the anthocyan(id)ins used in this study were capable of inducing significant oxidative DNA strand cleavage (nicking) in the presence of 1 mM dithiothreitol, while the free radical scavenger, dimethyl sulfoxide (DMSO), at concentrations typically used in similar studies, completely inhibited DNA nicking. Finally, we proposed a mechanism to explain the anthocyan(id)in-induced oxidative DNA cleavage observed under our experimental conditions. PRACTICAL APPLICATIONS This study provided improved understanding of the mechanisms by which anthocyan(id)ins interact with DNA. By characterizing the chemistry and solution properties of these important dietary components, we obtained improved information on how the anthocyan(id)ins might function in living systems. [source] Interleukin-1, Induces Cyclooxygenase-2 and Prostaglandin E2 Synthesis in Human Neuroblastoma CellsJOURNAL OF NEUROCHEMISTRY, Issue 5 2000Involvement of p38 Mitogen-Activated Protein Kinase, Nuclear Factor- Abstract: Prostaglandins (PGs), which are generated by the enzymatic activity of cyclooxygenase (COX)-1 and -2, modulate several functions in the CNS such as the generation of fever, the sleep/wake cycle, and the perception of pain. Moreover, the neuronal induction of COX-2 has been linked to neuroinflammatory aspects of Alzheimer's disease (AD). The regulation of COX expression in neuronal cells is only partly understood and has been mainly linked to synaptic activity. In pathophysiological situations, however, cytokines may be potent stimulators of neuronal COX expression. Here we show that interleukin (IL)-1, induces COX-2 mRNA and protein synthesis and the release of PGE2 in the human neuroblastoma cell line SK-N-SH. We further demonstrate that both a free radical scavenger and an inhibitor of p38 mitogen-activated protein kinase (MAPK) reduce IL-1,-induced synthesis of COX-2. IL-1, induces p38 MAPK phosphorylation and activation of the nuclear factor-,B independently from each other. Our data suggest that IL-1,-induced COX-2 expression in SK-N-SH cells is regulated by different mechanisms, presumably involving mRNA transcription and mRNA stability. The ability of p38 MAPK to augment COX-2 expression in human neuroblastoma cells, as shown here, suggests that p38 MAPK may be involved in neuronal expression of COX-2 in AD. [source] Polyhydroxylated fullerene derivative C60(OH)24 prevents mitochondrial dysfunction and oxidative damage in an MPP+ -induced cellular model of Parkinson's diseaseJOURNAL OF NEUROSCIENCE RESEARCH, Issue 16 2008Xiaoqing Cai Abstract To find effective agents for Parkinson's disease (PD) prevention and therapy, we examined the protective effects of the polyhydroxylated fullerene derivative C60(OH)24 in a 1-methyl-4-phenylpyridinium (MPP+)-induced acute cellular PD model in human neuroblastoma cells and the free radical scavenging effects in this model with an electron spin resonance (ESR) spectrometer. Pretreatment with C60(OH)24 at concentrations greater than 20 ,M showed significant protective effects on MPP+ -induced loss in cell viability, decreases in mitochondrial function (including mitochondrial membrane potential and activities of complex I and II), and increases in the levels of reactive oxygen species and oxidative damage to DNA and proteins. In addition, C60(OH)24 acts as a phase 2 enzyme inducer to protect cells from MPP+ -induced decreases in expression of nuclear factor-E2-related factor 2, expression and activity of ,-glutamyl cysteine ligase and level of glutathione. The ESR study showed that C60(OH)24 is a powerful radical scavenger for superoxide, hydroxyl, and lipid radicals. These data suggest that C60(OH)24 is a mitochondrial protective antioxidant with direct radical scavenging activity and indirect antioxidant inducing activity. © 2008 Wiley-Liss, Inc. [source] The oxidation metabolites of endomorphin 1 and its fragments induced by free radicalsJOURNAL OF PEPTIDE SCIENCE, Issue 5 2009Pin Gong Abstract Endomorphin 1 (EM1), an endogenous µ-opioid receptor agonist, acts as a free radical scavenger in vitro and an antioxidant in vivo. The modification of EM1 by ROS and the properties of the OM attracted our attention. In vitro assays were performed via RP-HPLC, spectrophotometric measurements, EPR and amino acid analysis, Schmorl's reaction to define the formation of melanin-like compounds transformed from EM1, collectively named EM1,melanin and by solubility assay, radioligand-binding assay, NADH oxidation, superoxide anion scavenging assay to study some physical and chemical properties of EM1,melanin. Possible pathways of the formation of EM1,melanin were proposed. Copyright © 2009 European Peptide Society and John Wiley & Sons, Ltd. [source] Oxidative stress of the newborn in the pre- and postnatal period and the clinical utility of melatoninJOURNAL OF PINEAL RESEARCH, Issue 2 2009Eloisa Gitto Abstract:, Newborns, and especially those delivered preterm, are probably more prone to oxidative stress than individuals later in life. Also during pregnancy, increased oxygen demand augments the rate of production of reactive oxygen species (ROS) and women, even with normal pregnancies, experience elevated oxidative stress and lipid peroxidation compared with nonpregnant women. Also, there appears to be an increase in ROS generation in the placenta of pre-eclamptic women. In comparison with healthy adults, newborn infants have lower levels of plasma antioxidants such as vitamin E, ,-carotene, and sulphydryl groups, lower levels of plasma metal binding proteins including ceruloplasmin and transferrin, and reduced activity of erythrocyte superoxide dismutase. This review summarizes conditions of newborns where there is elevated oxidative stress. Included in this group of conditions is asphyxia, respiratory distress syndrome and sepsis and the review also summarizes the literature related to clinical trials of antioxidant therapies and of melatonin, a highly effective antioxidant and free radical scavenger. The authors document there is general agreement that short-term melatonin therapy may be highly effective and that it has a remarkably benign safety profile, even when neonates are treated with pharmacological doses. Significant complications with long-term melatonin therapy in children and adults also have not been reported. None of the animal studies of maternal melatonin treatment or in postnatal life have shown any treatment-related side effects. The authors conclude that treatment with melatonin might result in a wide range of health benefits, improved quality of life and reduced healthcare costs and may help reduce complications in the neonatal period. [source] Lipid,protein modifications during ascorbate-Fe2+ peroxidation of photoreceptor membranes: protective effect of melatoninJOURNAL OF PINEAL RESEARCH, Issue 3 2006Margarita H. Guajardo Abstract:, The rod outer segment (ROSg) membranes are essentially lipoprotein complexes. Rhodopsin, the major integral protein of ROSg, is surrounded by phospholipids highly enriched in docosahexaenoic acid (22:6 n3). This fluid environment plays an important role for conformational changes after photo-activation. Thus, ROSg membranes are highly susceptible to oxidative damage. Melatonin synthesized in the pineal gland, retina and other tissues is a free radical scavenger. The principal aim of this work was to study the changes in the ROSg membranes isolated from bovine retina submitted to nonenzymatic lipid peroxidation (ascorbate-Fe2+ induced), during different time intervals (0,180 min). Oxidative stress was monitored by increase in the chemiluminescence and fatty acid alterations. In addition we studied the in vitro protective effect of 5 mm melatonin. The total cpm originated from light emission (chemiluminescence) was found to be lower in those membranes incubated in the presence of melatonin. The docosahexaenoic acid content decreased considerably when the membranes were exposed to oxidative damage. This reduction was from 35.5 ± 2.9% in the native membranes to 12.65 ± 1.86% in those peroxidized during 180 min. In the presence of 5 mm melatonin we observed a content preservation of 22:6 n3 (23.85 ± 2.77%) at the same time of peroxidation. Simultaneously the alterations of membrane proteins under oxidative stress were studied using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Loss of protein sulfhydryl groups and increased incorporation of carbonyl groups were utilized as biomarkers of protein oxidation. In membranes exposed to Fe2+ -ascorbate, we observed a decrease of protein thiols from 50.9 ± 3.38 in native membranes to 1.72 ± 2.81 nmol/mg of protein after 180 min of lipid peroxidation associated with increased incorporation of carbonyl groups into proteins from 7.20 ± 2.50 to 12.50 ± 1.12 nmol/mg of protein. In the SDS-PAGE we observed a decrease in the content of all the proteins, mainly rhodopsin, as a consequence of peroxidation. Melatonin, prevent both lipid peroxidation and protein oxidation. [source] A melatonin-rich germplasm line of St John's wort (Hypericum perforatum L.)JOURNAL OF PINEAL RESEARCH, Issue 3 2006Susan J. Murch Abstract:, The objective of this study was to evaluate the possibility of selecting genetic variants of plants with enhanced concentrations of the indoleamine melatonin. A germplasm line of the medicinal plant species, St John's wort (Hypericum perforatum L.), with high levels of melatonin was selected in vitro using mutagenized tissues. The germplasm line has remained stable over a 5-yr period and contained >12-fold (1200%) melatonin content compared with the wild-type plant. Melatonin is a ubiquitous, highly conserved molecule with known therapeutic roles in the treatment of sleep disorders, depression, aging, inhibition of cancer cell growth and as a free radical scavenger and antioxidant. The selected melatonin-rich germplasm line of St John's wort may facilitate fundamental studies on melatonin biosynthesis, metabolism and new developments in natural products for treatment of human diseases. [source] Potent therapeutic effect of melatonin on aging skin in pinealectomized ratsJOURNAL OF PINEAL RESEARCH, Issue 3 2005Mukaddes E Abstract:, It is generally agreed that one of the major contributors to skin aging is reactive oxygen species. As organisms reach advanced age, free radical generation increases and the activity of tissue antioxidant enzyme system decreases. Melatonin is an antioxidant and free radical scavenger. The present study was first aimed to determine the morphometric and biochemical changes caused by long-term pinealectomy in order to investigate the role of melatonin as skin architecture. Secondly, the effect of exogenous melatonin administration on these changes was determined. Rats were pinealectomized or sham operated (control) for 6 months. Half of the pinealectomized rats were treated with 4 mg/kg melatonin during the last month of the experiment. Pinealectomy resulted in important morphometric and biochemical changes in the back, abdominal and thoracic skin. The thickness of epidermis and dermis and the number of dermal papillae and hair follicles were reduced. Melatonin administration to pinealectomized rats significantly improved these alterations in all body areas (P < 0.005). On the contrary, in pinealectomized rats the levels of antioxidant enzymes, catalase and glutathione peroxidase were decreased. Melatonin restored the levels of these enzymes. The pinealectomy-induced increases in lipid peroxidation in the abdominal and thoracic skin were significantly reduced by melatonin treatment (P < 0.005 and 0.01 respectively). These results suggest that melatonin is highly efficient anti-aging factor and, as melatonin levels decrease with age, melatonin treatment may reduce age-related skin changes. [source] Melatonin generates singlet oxygen on laser irradiation but acts as a quencher when irradiated by lamp photolysisJOURNAL OF PINEAL RESEARCH, Issue 3 2005D. S. Maharaj Abstract:, Melatonin, a naturally occurring chemical mediator, although assigned a diverse range of functions, has attracted interest in recent years because of its ability to function as a free radical scavenger. Because of the implications of singlet oxygen in neurotoxicity, the objective of the study was to investigate the ability of melatonin to quench singlet oxygen generated using laser irradiation or lamp photolysis. The results show that melatonin produces radicals upon laser irradation while the lamp photolysis studies show that melatonin is able to scavenge singlet oxygen produced by naphthalene. While melatonin is a free radical scavenger under biological conditions, it acts as a generator of singlet oxygen and or radicals (as ,, is 1.41) when irradiated with laser light, implying that it has the potential to be used in photodynamic therapy in the destruction of tumors. [source] Melatonin ameliorates chronic renal failure-induced oxidative organ damage in ratsJOURNAL OF PINEAL RESEARCH, Issue 4 2004Göksel, ener Abstract:, Chronic renal failure (CRF) is associated with oxidative stress that promotes production of reactive oxygen species (ROS). Melatonin, the chief secretory product of the pineal gland, was recently found to be a potent free radical scavenger and antioxidant. The aim of this study was to examine the role of melatonin in protecting the aorta, heart, corpus cavernosum, lung, diaphragm, and kidney tissues against oxidative damage in a rat model of CRF, which was induced by five of six nephrectomy. Male Wistar albino rats were randomly assigned to either the CRF group or the sham-operated control group, which had received saline or melatonin (10 mg/kg, i.p.) for 4 wk. CRF was evaluated by serum blood urea nitrogen (BUN) level and creatinine measurements. Aorta and corporeal tissues were used for contractility studies, or stored along with heart, lung, diaphragm, and kidney tissues for the measurement of malondialdehyde (MDA, an index of lipid peroxidation), protein carbonylation (PC, an index for protein oxidation), and glutathione (GSH) levels (a key antioxidant). Plasma MDA, PC, and GSH levels and erythrocytic superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) activities were studied to evaluate the changes of antioxidant status in CRF. In the CRF group, the contraction and the relaxation of aorta and corpus cavernosum samples decreased significantly compared with controls (P < 0.05,0.001). Melatonin treatment of the CRF group restored these responses. In the CRF group, there were significant increases in tissue MDA and PC levels in all tissues with marked reductions in GSH levels compared with controls (P < 0.05,0.001). In the plasma, while MDA and PC levels increased, GSH, SOD, CAT, and GSH-Px activities were reduced. Melatonin treatment reversed these effects as well. In this study, the increase in MDA and PC levels and the concomitant decrease in GSH levels of tissues and plasma and also SOD, CAT, GSH-Px activities of plasma demonstrate the role of oxidative mechanisms in CRF-induced tissue damage, and melatonin, via its free radical scavenging and antioxidant properties, ameliorates oxidative organ injury. CRF-induced dysfunction of the aorta and corpus cavernosum of rats was reversed by melatonin treatment. Thus, supplementing CRF patients with adjuvant therapy of melatonin may have some benefit. [source] Orally administered melatonin reduces oxidative stress and proinflammatory cytokines induced by amyloid- , peptide in rat brain: a comparative, in vivo study versus vitamin C and EJOURNAL OF PINEAL RESEARCH, Issue 2 2003Sergio Rosales-Corral Abstract: To determine the efficacy of antioxidants in reducing amyloid- , -induced oxidative stress, and the neuroinflammatory response in the central nervous system (CNS) in vivo, three injections of fibrillar amyloid- , (fA,) or artificial cerebrospinal fluid (aCSF) into the CA1 region of the hippocampus of the rat were made. Concomitantly, one of the three free radical scavengers, i.e. melatonin, vitamin C, or vitamin E was also administered. Besides being a free radical scavenger, melatonin also has immunomodulatory functions. Antioxidant treatment reduced significantly oxidative stress and pro-inflammatory cytokines. There were no marked differences between melatonin, vitamin C, and vitamin E regarding their capacity to reduce nitrites and lipoperoxides. However, melatonin exhibited a superior capacity to reduce the pro-inflammatory response induced by fA,. [source] Melatonin protects hepatic mitochondrial respiratory chain activity in senescence-accelerated miceJOURNAL OF PINEAL RESEARCH, Issue 3 2002Yuji Okatani Mitochondrial oxidative damage from free radicals may be a factor underlying aging, and melatonin, a powerful free radical scavenger, may participate in mitochondrial metabolism. We measured respiratory chain complex I and IV activities in liver mitochondria from a strain of senescence-accelerated prone mice (SAMP8) and a strain of senescence-accelerated resistant mice (SAMR1) at age 3, 6, and 12 months. No age-associated effects were found in either complex I and IV activities, thiobarbituric acid-reactive substances (TBARS), or glutathione peroxidase (GPx) activity in SAMR1. In contrast, SAMP8 showed significant age-associated decreases in complex I and IV activities. While no age effect was found in TBARS in SAMP8, TBARS levels in SAMP8 were significantly more abundant than in SAMR1. GPx activity in SAMP8 decreased significantly by 12 months. Daily oral melatonin administration (2 ,g/mL of drinking fluid) beginning when the mice were 7 months old significantly increased complex I and IV activity, decreased TBARS, and increased GPx activities in both SAMR1 and SAMP8 at 12 months. The implication of the findings is that melatonin may be beneficial during aging as it reduced the deteriorative oxidative changes in mitochondria and other portions of the cell associated with advanced age. [source] Use of intravenous lidocaine to prevent reperfusion injury and subsequent multiple organ dysfunction syndromeJOURNAL OF VETERINARY EMERGENCY AND CRITICAL CARE, Issue 3 2003Benjamin H. Cassutto DVM Abstract Objective: The objective of this article is to review the human and veterinary literature and provide evidence for the potential beneficial effects of intravenous (IV) lidocaine hydrochloride in preventing post-ischemic,reperfusion injury, the systemic inflammatory response syndrome (SIRS), and subsequent multiple organ dysfunction syndrome (MODS). Human data synthesis: Lidocaine is a local anesthetic and antiarrhythmic agent that has been used for years in human and veterinary medicine for the treatment of ventricular dysrhythmias associated with blunt cardiac trauma, myocardial ischemia, and cardiac surgery. More recently, the drug has been touted as a scavenger of reactive oxygen species (ROS), and has been used to prevent reperfusion dysrhythmias after treatment of myocardial infarction, cross-clamping of the aorta, and in trauma medicine. Veterinary data synthesis: Although no clinical experiments with prophylactic intravenous lidocaine exist in veterinary medicine, there is a large body of evidence from experimental animals that support the use of lidocaine as a Na+/Ca2+ channel blocker, superoxide and hydroxyl radical scavenger, inflammatory modulator, and potent inhibitor of granulocyte functions. Lidocaine is being used in some clinical situations in an attempt to prevent the SIRS in veterinary trauma patients.a,b Conclusions: A large body of experimental evidence exists supporting the use of lidocaine as an anti-oxidant and inflammatory modulator useful in preventing reperfusion injury. With the lack of cost-effective and safe treatments for reperfusion injury in veterinary and human trauma medicine, the use of IV lidocaine to prevent the ensuing inflammatory response and MODS makes it an attractive addition to existing treatments. Therefore, it is essential that prospective clinical trials involving lidocaine as a treatment for prevention of reperfusion injury be performed in companion animals to demonstrate its safety and efficacy. [source] Red blood cells attenuate sinusoidal endothelial cell injury by scavenging xanthine oxidase-dependent hydrogen peroxide in hyperoxic perfused rat liverLIVER INTERNATIONAL, Issue 3 2000Satoru Motoyama Abstract:Aims/Background: Rat liver perfused with an oxygenated buffered solution alone results in degenerative changes even when the perfusion flow is accelerated to give a sufficient oxygen supply. On the other hand, perfusion media supplemented with red blood cells (RBCs) preserve the viability of the liver. The present study was conducted to clarify how RBCs protect the isolated perfused liver. Methods: The liver was perfused with and without RBCs in a perfusate equilibrated with supra-physiological oxygen tension at regulated inflow pressures, and controlled hepatic oxygen consumption. We examined alanine aminotransferase and purine nucleoside phosphorylase activity in the perfusate as specific markers of liver cells injury. Hydrogen peroxide (H2O2) production and morphological changes were determined using cerium electron microscopy. Apoptosis was detected by measuring CPP 32 protease activity and using TdT-mediated dUTP-digoxigenin nick end-labeling. Results: When the liver was perfused with RBC-free buffer, H2O2 production and consequent injury progressing to apoptosis were initiated in the sinusoidal endothelial cells (SECs). After SECs were injured, H2O2 appeared in the hepatocytes. H2O2 production and associated degenerative changes were attenuated both morphologically and enzymatically by the addition of RBCs, a specific xanthine oxidase (XOD) inhibitor and the H2O2 radical scavenger, catalase. Conclusions: In the liver perfused with RBC-free buffer, H2O2 production and consequent injury were initiated in SECs. RBCs attenuate liver injury by scavenging XOD-dependent H2O2. [source] Screening of chemiluminescence constituents of cereals and DPPH radical scavenging activity of ,-oryzanolLUMINESCENCE: THE JOURNAL OF BIOLOGICAL AND CHEMICAL LUMINESCENCE, Issue 3 2001Yoshinobu Akiyama Abstract The chemiluminescence (CL) constituents of cereals were detected by CL using the H2O2,acetaldehyde system. The cereals tested, such as rice, millet and sorghum, exhibited various levels of CL activity. The ,-oryzanol fraction was extracted from brown rice and separated into four constituents by HPLC. The four constituents were identified as cycloartenyl ferulate, 24-methylenecycroartanyl ferulate, campesteryl ferulate and ,-sitosteryl ferulate. Free radical scavenging activities with 1,1-diphenyl-2-picrylhydrazyl (DPPH) and CL intensities of four constituents (,-oryzanol components) were measured and compared with that of gallic acid, which is a typical free radical scavenger. Four constituents scavenged DPPH radicals and scavenging activities were proportional to CL intensities. Concentrations of four CL constituents required to quench 50% (IC50) of the free radicals ranged from 0.9 to 1.1,mmol/L. We demonstrated that measurement of CL intensities was a rapid and convenient method for screening DPPH radical scavenging activities of rice. Copyright © 2001 John Wiley & Sons, Ltd. [source] Plumbagin induces reactive oxygen species, which mediate apoptosis in human cervical cancer cellsMOLECULAR CARCINOGENESIS, Issue 4 2004Priya Srinivas There is an emerging evidence that plumbagin (5-hydroxy-2-methyl-1, 4-naphthoquinone) may have potential as a chemotherapeutic agent. However, the growth inhibitory mechanisms of plumbagin have remained unexplored. The aim of the study was to determine whether plumbagin-induced cell death in human cervical cancer cell line, ME-180, exhibited biochemical characteristics of apoptosis and to check whether N -acetyl- l -cysteine (NAC), which is a free radical scavenger, can reverse the cytotoxic effects of plumbagin. It can be concluded from the results that plumbagin inhibits the growth of ME-180 cells in a concentration and time-dependent manner. The cytotoxic effect of plumbagin induced cell death is through the generation of reactive oxygen species (ROS) and subsequent induction of apoptosis as demonstrated by the present data. Treatment of cells with plumbagin caused loss of mitochondrial membrane potential (,,m), and morphological changes characteristic of apoptosis, such as the translocation of phosphatidyl serine, nuclear condensation, and DNA fragmentation. Moreover, plumbagin-induced apoptosis involved release of mitochondrial cytochrome c and apoptosis inducing factor (AIF), thus activation of caspase-dependent and -independent pathways, as shown by the plumbagin-mediated activation of caspase-3 and -9. Our results also show that pretreatment of ME-180 cells with NAC blocks plumbagin-induced loss of ,,m and subsequent release of cytochrome c, AIF, and caspase-9 and -3 activation, thus inhibiting the apoptotic ability of plumbagin. © 2004 Wiley-Liss, Inc. [source] Neurological outcome after experimental cardiopulmonary resuscitation: a result of delayed and potentially treatable neuronal injury?ACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 5 2002X. L. Liu Background: In experimental cardiopulmonary resuscitation (CPR) aortic balloon occlusion, vasopressin, and hypertonic saline dextran administration improve cerebral blood flow. Free radical scavenger ,-phenyl-N-tert-butyl-nitrone (PBN) and cyclosporine-A (CsA) alleviate neuronal damage after global ischemia. Combining these treatments, we investigated neurological outcome after experimental cardiac arrest. Methods: Thirty anesthetized piglets, randomly allocated into three groups, were subjected to 8 min of ventricular fibrillation followed by 5 min of closed-chest CPR. The combined treatment (CT) group received all the above-mentioned modalities; group B was treated with balloon occlusion and epinephrine; and group C had sham balloon occlusion with epinephrine. Indicators of oxidative stress (8-iso-PGF2,), inflammation (15-keto-dihydro-PGF2,), energy crisis (hypoxanthine and xanthine), and anoxia/hypoxia (lactate) were monitored in jugular bulb venous blood. Neurological outcome was evaluated 24 h after CPR. Results: Restoration of spontaneous circulation (ROSC) was more rapidly achieved and neurological outcome was significantly better in the CT group, although there was no difference in coronary perfusion pressure between groups. The jugular venous PCO2 and cerebral oxygen extraction ratio were lower in the CT group at 5,15 min after ROSC. Jugular venous 8-iso-PGF2, and hypoxanthine after ROSC were correlated to 24 h neurological outcome Conclusions: A combination of cerebral blood flow promoting measures and administration of ,-phenyl-N-tert-butyl-nitrone and cyclosporine-A improved 24 h neurological outcome after 8 min of experimental normothermic cardiac arrest, indicating an ongoing neuronal injury in the reperfusion phase. [source] Ultraviolet B Light-induced Nitric Oxide/Peroxynitrite Imbalance in Keratinocytes,Implications for Apoptosis and NecrosisPHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 2 2010Shiyong Wu Elevation of nitric oxide (NO,) can either promote or inhibit ultraviolet B light (UVB)-induced apoptosis. In this study, we determined real-time concentration of NO, and peroxynitrite (ONOO,) and their role in regulation of membrane integrity and apoptosis. Nanosensors (diameter 300,500 nm) were used for direct in situ simultaneous measurements of NO, and ONOO, generated by UVB in cultured keratinocytes and mice epidermis. An exposure of keratinocytes to UVB immediately generated ONOO, at maximal concentration of 190 nm followed by NO, release with a maximal concentration of 91 nm. The kinetics of UVB-induced NO,/ONOO, was in contrast to cNOS agonist stimulated NO,/ONOO, from keratinocytes. After stimulating cNOS by calcium ionophore (CaI), NO, release from keratinocytes was followed by ONOO, production. The [NO,] to [ONOO,] ratio generated by UVB decreased below 0.5 indicating a serious imbalance between cytoprotective NO, and cytotoxic ONOO,,a main component of nitroxidative stress. The NO,/ONOO, imbalance increased membrane damage and cell apoptosis was partially reversed in the presence of free radical scavenger. The results suggest that UVB-induced and cNOS-produced NO, is rapidly scavenged by photolytically and enzymatically generated superoxide (O2,,) to produce high levels of ONOO,, which enhances oxidative injury and apoptosis of the irradiated cells. [source] Secoiridoid glucosides with free radical scavenging activity from the leaves of Syringa dilatataPHYTOTHERAPY RESEARCH, Issue 4 2003Hyuncheol Oh Abstract Activity-guided fractionation of the EtOAc and MeOH extract of the leaves of Syringa dilatata NAKAI furnished one free radical scavenger, the secoiridoid glucoside oleuropein together with ligstroside and an iridoid glucoside, syringopicroside. Oleuropein interacted with the stable free radical, 1,1-diphenyl-2-picrylhydrazyl (DPPH), and showed an IC50 value of 40.4 µM. L-Ascorbic acid as a positive control showed an IC50 value of 50.3 µM. Copyright © 2003 John Wiley & Sons, Ltd. [source] Inhibitory effects of echinoisoflavanone and sophoraisoflavanone D in Sophora chrysophylla SEEM on copper ion-induced protein oxidative modification of mouse brain homogenate in vitroPHYTOTHERAPY RESEARCH, Issue 4 2002Shizuo Toda Abstract We present the results of an in vitro investigation of the inhibitory effects of echinoisoflavanone and sophoraisoflavanone D isolated from Sophora chrysophylla SEEM on copper-induced protein oxidative modification of mouse brain homogenate in vitro. They inhibited copper-induced protein oxidative modification. The order of inhibitory effects of these isoflavanones and mannitol as a hydroxyl radical scavenger was sophoraisoflavanone D > mannitol > echinoisoflavanone. The results suggest that these natural products may be of use in cases where oxidative stress is present. Copyright © 2002 John Wiley & Sons, Ltd. [source] Free radical generation during the activation of hemolymph prepared from the homopteran Dactylopius coccusARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY (ELECTRONIC), Issue 1 2007F. García-Gil De Muñoz Abstract Superoxide anion (O,2) and nitric oxide (NO) generation in Dactylopius coccus hemolymph obtained by perfusion and activated with zymosan was studied. Activated hemolymph reduced 3-[4,5 dimethylthiazolil-2]-2,5-diphenyl tetrazolium bromide. This reduction was prevented by superoxide dismutase (SOD) indicating O,2 generation. This activity was dependent on temperature, and hemolymph incubated at 75°C lost its activity. Chromatocytes incubated with zymosan released their content and produced O,2. Activated hemolymph also produced NO and this activity was prevented in the presence of NG-nitro-L-arginine methyl ester, suggesting that nitric oxide synthase (NOS) might be present in D. coccus hemolymph. The probable source of O,2 in the D. coccus hemolymph is the anthraquinone oxidation, since commercial carminic dye produced O,2 during its oxidation by Agaricus bisporus tyrosinase. Gram+ Micrococcus luteus exposed to activated hemolymph were killed in vitro, and addition of NG-nitro-L-arginine methyl ester and D-Mannitol (a hydroxyl radical scavenger) prevented their killing. The cytotoxic effect produced by the activated hemolymph was not observed with the Gram, bacteria Serratia marcescens. These results suggest that D. coccus activated hemolymph generates reactive oxygen intermediates (ROI) and reactive nitrogen intermediates (RNI) that may limit M. luteus growth. Arch. Insect Biochem. Physiol. 65:20,28, 2007. © 2007 Wiley-Liss, Inc. [source] Degradation of tetracycline in aqueous medium by electrochemical methodASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 5 2009Hui Zhang Abstract The degradation of tetracycline by anode oxidation with Ti/RuO2,IrO2 electrode was carried out in an electrochemical cell. The effect of operating conditions such as electrical current density, initial pH, antibiotic concentration, electrolyte concentration and hydroxyl radical scavenger on the oxidation of tetracycline was investigated. The results showed that the degradation of tetracycline followed apparent pseudo-first-order kinetics. The rate constant increased linearly with the current density, but the oxidation curves displayed the same dependence on the amount of the specific charge passed. The degradation rate decreased with the initial antibiotic concentration. Either initial pH or electrolyte concentration had little effect on the electrochemical oxidation of tetracycline. The presence of tert -butanol did not hinder the degradation rate, indicating the radical contribution to the oxidation of tetracycline could be neglected. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source] Protective effects of melatonin and indole-3-propionic acid against lipid peroxidation, caused by potassium bromate in the rat kidneyCELL BIOCHEMISTRY AND FUNCTION, Issue 6 2006gorzata Karbownik Abstract Potassium bromate (KBrO3) is classified as a carcinogenic agent. KBrO3 induces tumors and prooxidative effects in kidneys. Melatonin is a well known antioxidant and free radical scavenger. Indole-3-propionic acid (IPA), an indole substance, also reveals antioxidative properties. Recently, some antioxidative effects of propylthiouracil (PTU),an antithyroid drug,have been found. The aim of the study was to compare protective effects of melatonin, IPA, and PTU against lipid peroxidation in the kidneys and blood serum and, additionally, in the livers and the lungs, collected from rats, pretreated with KBrO3. Male Wistar rats were administered KBrO3 (110 mg/kg b.w., i.p., on the 10th day of the experiment) and/or melatonin, or IPA (0.0645 mmol/kg b.w., i.p., twice daily, for 10 days), or PTU (0.025% solution in drinking water, for 10 days). The level of lipid peroxidation products,malondialdehyde,+,4-hydroxyalkenals (MDA,+,4-HDA),was measured spectrophotometrically in thyroid homogenates. KBrO3, when injected to rats, significantly increased lipid peroxidation in the kidney homogenates and blood serum, but not in the liver and the lung homogenates. Co-treatment with either melatonin or with IPA, but not with PTU, decreased KBrO3 -induced oxidative damage to lipids in the rat kidneys and serum. In conclusion, melatonin and IPA, which prevent KBrO3 -induced lipid peroxidation in rat kidneys, may be of great value as protective agents under conditions of exposure to KBrO3. Copyright © 2006 John Wiley & Sons, Ltd. [source] Radiolysis of Confined Water: Hydrogen Production at a High Dose RateCHEMPHYSCHEM, Issue 12 2005Sophie Le Caër Dr. Abstract The production of molecular hydrogen in the radiolysis of dried or hydrated nanoporous controlled-pore glasses (CPG) has been carefully studied using 10 MeV electron irraditation at high dose rate. In all cases, the H2 yield increases when the pore size decreases. Moreover, the yields measured in dried materials are two orders of magnitude smaller than those obtained in hydrated glasses. This proves that the part of the H2 coming from the surface of the material is negligible in the hydrated case. Thus, the measured yields correspond to those of nanoconfined water. Moreover, these yields are not modified by the presence of potassium bromide, which is a hydroxyl radical scavenger. This experimental observation shows that the back reaction between H2 and HO. does not take place in such confined environments. These porous materials have been characterized before and after irradiation by means of Fourier-transform infrared (FT-IR) spectroscopy, electron paramagnetic resonance (EPR) and nuclear magnetic resonance (NMR) techniques, which helps to understand the elementary processes taking place in this type of environment, especially the protective effect of water on the surface in the case of hydrated glasses. [source] Effect of N -acetylcysteine on the early expression of inflammatory markers in the retina and plasma of diabetic ratsCLINICAL & EXPERIMENTAL OPHTHALMOLOGY, Issue 2 2009Gina Y Tsai MD Abstract Purpose:, The aim of this study is to investigate markers of inflammation and oxidative stress in an early model of diabetic retinopathy, correlate retinal and plasma results and evaluate the influence of treatment by N -acetylcysteine (NAC), a free radical scavenger. Methods:, Four groups were studied: control (C), streptozotocin (STZ)-induced diabetic rats (D), STZ rats following 8 weeks of NAC (DT), and control rats following 8 weeks of NAC (CT). Plasma levels of free 15-F2t-isoprostane (15-F-2t-IsoP), superoxide dismutase (SOD) and tumour necrosis factor-alpha (TNF-,) were obtained. Primary antibodies against macrophages (ED-1), microglia (Ox-42), pericytes (NG-2), endothelial and perivascular cells (IB-4), haem oxygenase 1 (HO-1) and vascular endothelial growth factor (VEGF) were used. Results:, Expression of NG-2 was robust in C, CT, DT, and mild in D. The intensity of IB-4 was higher in D and DT compared with the C and CT. Ox-42 and ED-1 expression was higher in the D than in the DT, C or CT. Expression of VEGF and HO-1 was non-specific across the four groups. Plasma levels of 15-F-2t-IsoP and TNF-, were higher in the D as compared with the C, CT and DT. SOD levels were lower in the D when compared with the C, CT and D. Conclusions:, Macrophage/microglia activation, pericyte loss and endothelial/perivascular cell changes occur early in the pathogenesis of DR. These changes are associated with an increase in plasma markers of oxidative stress and inflammation and are minimized by treatment with NAC. The results suggest that therapies that reduce free radicals will help minimize the early events in diabetic retinopathy in the STZ model. [source] | ||||||||||||||||||||||||||||