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Showing papers on "Hydrogen peroxide published in 1994"


Patent
28 Feb 1994
TL;DR: Sodium percarbonate is often used in the form of coated particles to increase its storage stability in detergents as mentioned in this paper, where perborax with the formula Na 2 B 4 O 7 ·H 2 O 2, where n = 2 or 4.
Abstract: Sodium percarbonate is often used in the form of coated particles to increase its storage stability in detergents. Sodium percarbonate particles coated in accordance with the invention have a coating containing reaction products from the reaction of a dialkali metal tetraborate or alkali metal pentaborate with aqueous hydrogen peroxide. Preferred coating components are: perborax with the formula Na 2 B 4 O 7 ·H 2 O 2 , where n =2 or 4. The coated sodium percarbonate particles are produced by coating the percarbonate particles using a solution containing the reaction products mentioned above. Detergent, bleaching and cleaning compositions containing sodium percarbonate particles coated in accordance with the invention are distinguished by very high stability in storage.

405 citations


Journal ArticleDOI
TL;DR: It is concluded that capsaicin or curcumin in combination with dietary fatty acids differentially lowers the production of ROS in macrophages.

395 citations


Journal ArticleDOI
23 Jun 1994-Nature
TL;DR: In this paper, it was shown that manganese complexes derived from l,4,7-trimethyl-l, 4,4-7-triazacyclononane and related ligand systems act as highly effective catalysts for the bleaching of stains by hydrogen peroxide at low temperatures.
Abstract: THE detergents of the next century will be routinely required to contain bleaching agents that are not only more active than those currently available but also environmentally safe and cost-effective. Hydrogen peroxide, the traditional bleaching agent1, loses its activity as the washing temperature decreases. Peroxyacetic acid maintains acceptable bleaching activity down to 40–60 °C (ref. 2), but still lower temperatures are desirable. It is generally recognized that manganese and iron complexes are less environmentally damaging reagents than other transition-metal compounds, and such complexes have received considerable attention as bleaching catalysts3–11. Here we show that manganese complexes derived from l,4,7-trimethyl-l,4,7-triazacyclononane and related ligand systems act as highly effective catalysts for the bleaching of stains by hydrogen peroxide at low temperatures. These complexes also catalyse the epoxidation of alkenes and the oxidation of poh phenolic substrates by hydrogen peroxide. Our results demonstrate the considerable potential of these systems for clean and efficient low-temperature bleaching.

395 citations


Journal ArticleDOI
TL;DR: There is a role for calcium in plant responses to oxidative stress and pretreated seedlings with buthionine sulfoximine and inhibitors of ascorbate peroxidase modify the hydrogen peroxide-induced transients in [Ca2+]cyt, suggesting that these three signals mobilize different pools of intracellular calcium.
Abstract: Tobacco (Nicotiana plumbaginifolia) seedlings genetically transformed to express apoaequorin were incubated in h-coelenterazine to reconstitute the calcium-sensitive luminescent protein aequorin. Treatment of these seedlings with hydrogen peroxide resulted in a transient burst of calcium-dependent luminescence lasting several minutes. Even though the hydrogen peroxide stimulus was persistent, the change in cytosolic free calcium concentration ([Ca2+]cyt) was transient, suggesting the presence of a refractory period. When seedlings were pretreated with hydrogen peroxide, there was no increase in [Ca2+]cyt upon a second application, which confirmed the refractory character of the response. Only when the two treatments were separated by 4 to 8 hr was full responsiveness recovered. However, treatment with hydrogen peroxide did not inhibit mobilization of [Ca2+]cyt induced by either cold shock or touching, suggesting that these three signals mobilize different pools of intracellular calcium. To examine whether [Ca2+]cyt is regulated by the redox state of the cytoplasm, we pretreated seedlings with buthionine sulfoximine (to modify cellular glutathione levels) and inhibitors of ascorbate peroxidase. These inhibitors modify the hydrogen peroxide-induced transients in [Ca2+]cyt, which is consistent with their effects on the cellular prooxidant/antioxidant ratio. Treatment with hydrogen peroxide that elicited [Ca2+]cyt increases also brought about a reduction in superoxide dismutase enzyme activity. This reduction could be reversed by treatment with the calcium channel blocker lanthanum. This indicates that there is a role for calcium in plant responses to oxidative stress.

395 citations


Journal ArticleDOI
TL;DR: The results indicate that .NO release is part of the integrated response of stimulated human neutrophils and that, in these cells, kinetics of ″NO and O2 .− release favour the formation of other oxidants like peroxynitrite.

357 citations


Journal ArticleDOI
TL;DR: Reduced intermediates of molecular oxygen, such as superoxide and hydrogen peroxide, are ubiquitous inorganic products of normal aerobic metabolism, but most cells require antioxidant protection against excessive production of these intermediates.

298 citations


Patent
13 Oct 1994
TL;DR: In this article, the present invention relates to novel variants of Coprinus cinereus peroxidase showing excellent hydrogen peroxide stability, and is described in detail.
Abstract: The present invention relates to novel variants of Coprinus cinereus peroxidase showing excellent hydrogen peroxide stability.

291 citations



Journal ArticleDOI
TL;DR: It is shown that little, if any, of the additional oxygen consumed is converted to hydrogen peroxide, and it is proposed that this occurs via an initial reaction of superoxide with GSH to produce a sulfinyl radical rather than hydrogen transfer to give the thiyl radical.

254 citations


Book ChapterDOI
TL;DR: Myeloperoxidase (donor:hydrogen-peroxide oxidoreductase) is the most abundant protein in neutrophils and is also found in monocytes, and is a unique peroxid enzyme that catalyzes the conversion of hydrogen peroxide and chloride to hypochlorous acid.
Abstract: Publisher Summary Myeloperoxidase (donor:hydrogen-peroxide oxidoreductase) is the most abundant protein in neutrophils and is also found in monocytes. It contains two heme-prosthetic groups and is a unique peroxidase that catalyzes the conversion of hydrogen peroxide and chloride to hypochlorous acid. Hydrogen peroxide is formed from the spontaneous dismutation of superoxide, which is produced by an NADPH oxidase in the cell membrane. Hypochlorous acid is the major strong oxidant produced by neutrophils. It has powerful antimicrobial activity, and it is extremely reactive with biological molecules. It inactivates enzymes and α 1 -antitrypsin, cross-links proteins, and reacts with unsaturated fatty acids to form chlorohydrins, which may destabilize cell membranes. Given this broad spectrum of reactivity, hypochlorous acid is an obvious candidate for causing much of the damage mediated by neutrophils in inflammatory diseases. The ferric or native enzyme (MP 3+ ) reacts with hydrogen peroxide (H 2 O 2 ) to form the active redox intermediate compound I, which oxidizes chloride (CI - ) to hypochlorous acid (HOCl).

250 citations


Journal ArticleDOI
TL;DR: Investigation of the feasibility of using hydrogen peroxide as a chemical oxidant for in-situ treatment of contaminated surface soils found it decomposed readily by interacting with the natural iron content of sand, and additional ferrous salts further enhanced the extent of H 2 O 2 decomposition.
Abstract: The objective of this study was to investigate the feasibility of using hydrogen peroxide (H 2 O 2 ) as a chemical oxidant for in-situ treatment of contaminated surface soils. The process has been tested in the presence and absence of ferrous sulfate on sand-packed columns, which contained pentachlorophenol (PCP) and trichloroethylene (TCE) as model compounds. Both column and batch studies have demonstrated that H 2 O 2 decomposed readily by interacting with the natural iron content of sand, and additional ferrous salts further enhanced the extent of H 2 O 2 decomposition. As a result, PCP and TCE adsorbed on the sand surface were oxidized effectively and by stoichiometric release of organic bound chlorine as chloride ion

Journal ArticleDOI
TL;DR: The suitability of terephthalic acid (THA) as a hydroxyl radical dosimeter for general use in biologically relevant reactions is investigated and it is found that THA is non-fluorescent, eliminating the problem of a high initial background.

Journal ArticleDOI
TL;DR: The results of this study suggest that anaerobic pretreatment prior to advanced oxidation may be a viable means of reducing the ozone and hydrogen peroxide dosages required for biodegradability enhancement.
Abstract: Ozone in combination with hydrogen peroxide has been shown to effectly oxidize 1,4-dioxane in synthetic solutions representing groundwater or industrial wastewater to more readily biodegradable oxidation products that could be treated using conventional biological treatment. Bicarbonate alkalinity and competition by 1,3-dioxolane and 2-methyl-1,4-dioxolane were found to increase the oxidant dosages required for 1,4-dioxane oxidation. The results of this study suggest that anaerobic pretreatment prior to advanced oxidation may be a viable means of reducing the ozone and hydrogen peroxide dosages required for biodegradability enhancement

Journal ArticleDOI
TL;DR: In this article, the second-order rate constants for a wide range of inorganic and organic compounds, including a comprehensive series of phenols, have been determined using conventional batch-type and stopped-flow methods.

Journal ArticleDOI
TL;DR: Results suggest that titanium dioxide particles under UV light irradiation produced photogenerated holes on the surface yielding hydroxyl radicals and hydrogen peroxide inside or outside the cells and the cells were then killed by the action of these highly oxidising molecules.
Abstract: A photoexcited titanium dioxide surface has a strong ability to decompose water into hydrogen and oxygen. We have studied this effect in order to use it to kill cancer cells in vitro and in vivo. A distinct cell killing effect was observed on cultured T-24 human bladder cancer cells treated with titanium dioxide particles and 300-400 nm UV light irradiation. Titanium dioxide plus UV light also dramatically suppressed the tumour growth of T-24 cells that were implanted in nude mice. Cells cultured on the titanium dioxide electrode were also killed under UV irradiation when the electrode was anodically polarised, suggesting that photogenerated holes are involved in the cell killing. The cell killing effect caused by titanium dioxide particles plus UV light irradiation was significantly hampered in the presence of L-cysteine and catalase, scavengers of hydroxyl radicals and hydrogen peroxide respectively. Transmission electron microscopic observations showed the titanium dioxide particles to be distributed on the cell surface and inside the cells. These results suggest that titanium dioxide particles under UV light irradiation produced photogenerated holes on the surface yielding hydroxyl radicals and hydrogen peroxide inside or outside the cells and the cells were then killed by the action of these highly oxidising molecules. The possible application of photoexcited titanium dioxide particles to cancer treatment as a new anti-cancer modality is discussed.

Journal ArticleDOI
TL;DR: In this article, the antioxidant properties of Silibinin dihemisuccinate (SDH) were evaluated by studying the ability of this drug to react with relevant biological oxidants such as Superoxide anion radical (O ⨪ 2 ), hydrogen peroxide (H 2 O 2 ), hydroxyl radical (HO. ) and hypochlorous acid (HOCl).

Journal ArticleDOI
TL;DR: The results presented here suggest strongly that the reactive species is singlet oxygen generated via the Haber-Weiss reaction and not, as usually assumed, the hydroxyl radical, .OH, generated by the same reaction.
Abstract: Characteristic chemiluminescence emission of singlet (1 delta g) molecular oxygen at 1268 nm is reported from a Haber-Weiss reaction. The reaction consists of mixing aqueous hydrogen peroxide with a solution of potassium superoxide, solubilized by 18-crown-6 ether in carbon tetrachloride or in dry acetonitrile at room temperature. Since the discovery of the enzyme superoxide dismutase by J.M. McCord and I. Fridovich [(1968) J. Biol. Chem. 243, 5733-5760], the identity of the reactive oxidant in superoxide-generating systems in biology has remained a chemical mystery. The results presented here suggest strongly that the reactive species is singlet oxygen generated via the Haber-Weiss reaction and not, as usually assumed, the hydroxyl radical, .OH, generated by the same reaction.

Journal ArticleDOI
TL;DR: The possibility that the DCF fluorescence may be useful in estimating the intracellular content of hydrogen peroxide of mammalian brain neurons is suggested.

Journal ArticleDOI
TL;DR: In this paper, the properties of spin traps and N-tert-butyl-alpha-phenylnitrone or 5,5'-dimethyl-1-pyroline-Noxide were investigated to protect enzymes against oxidation by uv, hydrogen peroxide/uv, and ozone as determined by the preservation of activity and decreased carbonyl content.

Journal ArticleDOI
TL;DR: The response of glucose oxidase (GOx) modified poly(o-phenylenediamine) coated Pt disk electrodes to glucose was well-behaved with a rapid response time and displaying Michaelis-Menten kinetics but the glucose response was lowered in a concentration-dependent manner by ascorbic acid when the glucose calibrations were carried out in solutions containing this reducing agent.
Abstract: The response of glucose oxidase (GOx) modified poly(o-phenylenediamine) coated Pt disk electrodes to glucose was well-behaved with a rapid response time and displaying Michaelis-Menten kinetics. However, the glucose response was lowered in a concentration-dependent manner by ascorbic acid when the glucose calibrations were carried out in solutions containing this reducing agent. The possibility of a homogeneous redox reaction in which the H2O2 generated by tie enzymatic oxidation of glucose at the GOx/polymer surface is consumed by ascorbate was investigated. Similar ''negative'' interference at GOx-modified carbon powder electrodes not involving membranes and for H2O2 calibrations at bare Pt electrodes supported the hypothesis. The observation that this interference could be blocked by the chelating agent EDTA suggests that the homogeneous reaction is catalyzed by trace metal ion impurities in solution. A model for the homogeneous reaction based on these experimental findings is proposed and tested by comparing quiescent and stirred solutions. No homogeneous interference by uric acid was observed. The electrodes were found to be free from lipid fouling in vitro, and experiments monitoring brain glucose levels in vivo indicate the absence of the homogeneous reaction in this environment. The results highlight the need to test each individual assay procedure involving H2O2 under relevant conditions for both positive and negative interference by ascorbic acid.

Journal ArticleDOI
TL;DR: In this paper, the photooxidation of two non-biodegradable azo dyes, acid red 1 and acid yellow 23, were studied in an UV/hydrogen peroxide photochemical reactor with a 5 kW low pressure mercury lamp.

Journal ArticleDOI
TL;DR: It is suggested that the use of high concentrations of hydrogen peroxide for bleaching purposes should be limited, as sodium perborate appears to be a less damaging bleaching agent.

Journal ArticleDOI
TL;DR: It is shown that the post-translational modification of the cysteinyl thiols of glyceraldehyde-3-phosphate dehydrogenase accompanies an inhibition of the enzyme and that both events are simultaneously and rapidly reversed upon the removal of the oxidative stimulus.
Abstract: Exposure of human umbilical vein endothelial cells to oxidants such as hydrogen peroxide, tertbutyl hydroperoxide and diamide has been shown to induce oxidant-specific S-thiolation of cellular proteins. In this study one of the main S-thiolated proteins in hydrogen-peroxide-treated cells was identified as the glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase. Additionally, we have shown that the post-translational modification of the cysteinyl thiols of glyceraldehyde-3-phosphate dehydrogenase accompanies an inhibition of the enzyme and that both events are simultaneously and rapidly reversed upon the removal of the oxidative stimulus.

Journal ArticleDOI
TL;DR: It is shown that the peroxynitrite anion reacts with hydrogen peroxide to release oxygen accompanied by emission of chemiluminescence (CL), which is attributed to the transition of singlet molecular oxygen to the triplet ground state.

Journal ArticleDOI
TL;DR: H2O2 concentrations increase, an irreversible mechanism-based inactivation process becomes predominant, and HRP was inactivated in an irreversible, time- and phenol concentration-dependent process, also mechanism- based.

Journal ArticleDOI
TL;DR: To ascertain whether the oxidative stress is directed toward the Sp1 molecule alone, or whether it acts on unknown Sp1 cofactor(s) necessary for DNA binding, purified Sp1 from young rat liver and demonstrated that when the purified protein is added to aged nuclear extracts, it efficiently binds to its DNA cis-element.
Abstract: We have previously demonstrated that the DNA-binding efficiency of Sp1 is greatly decreased in nuclear extracts from 30-month-old rat tissues compared to those from young ones, although its gene appears to be normally expressed. As reactive oxygen intermediates are known to accumulate in aged animals, we investigated the effect of oxidation on the Sp1 DNA-binding activity. Electrophoretic mobility shift assays and DNase I footprintings showed that high concentrations of dithiothreitol, added to the aged tissue extracts, fully restore the Sp1 DNA-binding efficiency. However, in young nuclear extracts hydrogen peroxide treatment strongly decreases the Sp1 DNA-binding activity that is restored by the treatment with high dithiothreitol concentrations. To ascertain whether the oxidative stress is directed toward the Sp1 molecule alone, or whether it acts on unknown Sp1 cofactor(s) necessary for DNA binding, we purified Sp1 from young rat liver and demonstrated that when the purified protein is added to aged nuclear extracts, it efficiently binds to its DNA cis-element. Moreover, purified Sp1 treated with hydrogen peroxide lost its ability to bind its cis-element and the DNA-binding efficiency was fully restored after incubation with dithiothreitol.

Journal ArticleDOI
TL;DR: If high levels of H2O2 can be sustained for long periods of time, H 2O2 is an effective bactericidal agent, and the presence of LP and SCN- protects streptococci against killing by H2 O2.
Abstract: In secreted fluids, the enzyme lactoperoxidase (LP) catalyzes the oxidation of thiocyanate ion (SCN-) by hydrogen peroxide (H2O2), producing the weak oxidizing agent hypothiocyanite (OSCN-), which has bacteriostatic activity. However, H2O2 has antibacterial activity in the absence of LP and thiocyanate (SCN-). Therefore, LP may increase antibacterial activity by using H2O2 to produce a more effective inhibitor of bacterial metabolism and growth, or LP may protect bacteria against the toxicity of H2O2 by converting H2O2 to a less-potent oxidizing agent. To clarify the role of LP, the antibacterial activities of H2O2 and the LP-H2O2-SCN- system were compared by measuring loss of viability and inhibition of bacterial metabolism and growth. The relative toxicity of H2O2 and the LP system to oral streptococci was found to depend on the length of time that the bacteria were exposed to the agents. During incubations of up to 4 h, the LP system was from 10 to 500 times more effective than H2O2 as an inhibitor of glucose metabolism, lactic acid production, and growth. However, if no more H2O2 was added, the concentration of the inhibitor OSCN- fell because of slow decomposition of OSCN-, and when OSCN- fell below 0.01 mM, the bacteria resumed metabolism and growth. In contrast, the activity of H2O2 increased with time. H2O2 persisted in the medium for long periods of time because H2O2 reacted slowly with the bacteria and streptococci lack the enzyme catalase, which converts H2O2 to oxygen and water. After 24 h of exposure, H2O2 was as effective as the LP system as an inhibitor of metabolism. H2O2 also caused a time-dependent loss of viability, whereas the LP system had little bactericidal activity. The concentration of H2O2 required to kill half the bacteria within 15 s was 1.8 M (6%) but fell to 0.3 M (1%) at 2 min, to 10 mM (0.03%) at 1 h, and to 0.2 mM (0.0007%) with a 24-h exposure. The results indicate that if high levels of H2O2 can be sustained for long periods of time, H2O2 is an effective bactericidal agent, and the presence of LP and SCN- protects streptococci against killing by H2O2. Nevertheless, the combination of LP, H2O2, and SCN- is much more effective than H2O2 alone as an inhibitor of bacterial metabolism and growth.

Journal ArticleDOI
TL;DR: The results indicate that the passive film formed in the PBS solution--with and without addition of H2O2--may be described with a two-layer structure model.
Abstract: Electrochemical measurements, x-ray photoelectron spectroscopy, and scanning tunneling microscopy have been used to study the effect of hydrogen peroxide on the passivity of titanium in a phosphate-buffered saline (PBS) solution. The results indicate that the passive film formed in the PBS solution--with and without addition of H2O2--may be described with a two-layer structure model. The inner layer has a structure close to TiO2 whereas the outer layer consists of hydroxylated compounds. The introduction of H2O2 in the PBS solution broadens the hydroxylate-rich region, probably due to the formation of a Ti(IV)-H2O2 complex. Furthermore, the presence of H2O2 results in enhanced dissolution of titanium and a rougher surface on a microscopic scale. Finally, a dark pigmentation (blue color) is observed when titanium has been exposed--for several weeks--to PBS with additions of H2O2.


Journal ArticleDOI
TL;DR: These experiments prove that the increase of DCF fluorescence intensity observed during doxorubicin treatment is not due to technical artifacts but it is attributable to free radicals produced in the cells by the drug.