Peroxide Compounds Research Articles

Effect of Colchicine on Total Antioxidant Capacity, Antioxidant Enzymes and Oxidative Stress Markers in Patients with Knee Osteoarthritis

Background/Aim: We aimed to investigate the effects of colchicine on clinical recovery, as well as oxidative stress markers and total antioxidant capacity (TAC) in whole blood of patients with knee osteoarthritis (OA). Materials and methods: Sixty patients with grade 2 - 3 knee OA according to ACR knee OA criteria whom examination of the knee joint synovial fluid by polarized light microscopy demonstrated CPDD crystals existence were included in the study. Fifty healthy subjects were included as a control group. Patients were divided randomly into two groups. The first group (paracetamol group) was given only paracetamol 3 gr daily p.o and the second group (colchicine and paracetamol group) was given colchicine 1,5 gr and paracetamol 3 gr daily p.o for six months. For outcome measures WOMAC and VAS were used. Superoxide dismutase (SOD), Catalase (CAT) ezyme activities and Glutathione (GSH) and Malondialdehyde (MDA) levels and TAC all were measured. Results: WOMAC scores were improved in both patient groups compared with pre-treatment evaluation (p 0.05). TAC was signifcantly increased only in colchicine/paracetamol group. Oxidant parameter MDA levels were significantly decreased in both paracetamol group and colchicine/paracetamol group. CAT, SOD enzyme activities and GSH levels did not change before and after treatment protocols in both patient groups. Conclusion: Both paracetamol 3000 mg/day and 3000 mg paracetamol plus 1,5 gr/day colchicine is effective in the treatment of patients with knee osteoarthritis. But the addition of colchicine to paracetamol produced significantly greater symptomatic benefit than paracetamol alone. Our study also showed that colchicine lowers whole blood MDA which is a lipid peroxidation compound and elevates TAC levels in patients with knee OA. This may show probable disease modifying effect of colchicine in knee OA which require further long period laboratory and radiologic investigations.

Role of Laccase and Low Molecular Weight Metabolites fromTrametes versicolorin Dye Decolorization

The studies regarding decolorization of dyes by laccase may not only inform about the possible application of this enzyme for environmental purposes, but also may provide important information about its reaction mechanism and the influence of several factors that could be involved. In this paper, decolorization of crystal violet and phenol red was carried out with different fractions of extracellular liquids from Trametes versicolor cultures, in order to describe the role of laccase in this reaction. Moreover, the possible role of the low molecular weight metabolites (LMWMs) also produced by the fungus was evaluated. The results confirm the existence of a nonenzymatic decolorization factor, since the nonprotein fraction of the extracellular liquids from cultures of T. versicolor has shown decolorization capability. Several experiments were performed in order to identify the main compounds related to this ability, which are probably low molecular weight peroxide compounds.

Municipal River Sediment Remediation with Calcium Nitrate, Polyaluminium Chloride and Calcium Peroxide Compound

In situ laboratory studies were carried out in simulated reactors to evaluate the potential of calcium nitrate, Polyaluminium Chloride (PAC) and calcium peroxide for remediation municipal river sediment. Calcium peroxide could increase the dissolved oxygen concentration (DO) of water for long time (8 weeks). It would optimize the anoxia environment of sediment and be propitious for remediation of sediment. The disadvantage of calcium peroxide was that pH (8.6) would rise slightly and accelerate NH3-N release. Spraying poly-aluminum chloride also could prohibit phosphorus release from sediment. But the remediation effect might be weakened due to disorganization of the aluminium floc after period of time. Phosphorus release from sediment injected calcium nitrate was almost stopped during the experiment. Calcium nitrate could greatly improve the ability of bio-treatment properties for sediment. After 28 weeks of treatment, the TN concentration with dose of 70g per square meter NO3-N could reduce to common level compared to blank reactor by denitrification. It makes in-situ chemical remediation technology by calcium nitrate injection become possibly.

Antioxidant and Cytotoxic Activity of the Wild Edible Mushroom Gomphus clavatus

The fruiting bodies of the edible mushroom Gomphus clavatus (Family Gomphaceae) were collected from the wild and extracted with solvents of increasing polarity. Crude extracts were evaluated for their total phenolic content, their antioxidant capacity, and their cytotoxic activity against MCF-7 and PC-3 cancer cell lines. Concerning total phenolics and antioxidant activity, the methanol extract showed the most potent radical scavenging activity with inhibition of 45.5% of 1,1-diphenyl-2-picrylhydrazyl at 3 mg/mL. Further chemical investigation of the methanol extract led to the isolation and identification of nine compounds, among them four ergosterol derivatives. Concerning cytotoxicity, the dichloromethane (DCM) extract showed the most interesting activity, with half-maximal inhibitory concentration (IC(50)) values of 55.3 and 49.0 μg/mL in the MCF-7 and PC-3 cell lines, respectively. Further investigation of the DCM extract lead to the identification of methyl esters of fatty acids and the isolation of four fatty acids and three ergosterol derivatives. Ergosterol peroxide (compound 6) was one of the most active constituents, with IC(50) values of 35.8 μM and 30.6 μM for MCF-7 and PC-3 cells, respectively, suggesting that the cytotoxic activity of the crude extract could be at least partly attributed to the presence of ergostan derivatives. Those findings suggest that G. clavatus can be considered as a medicinal food with antioxidant and chemopreventive activities.

Antioxidant activity of amino acids during oxidation of sunflower oil in an emulsion

The influence of α-amino acid additions on the process of sunflower oil oxidation in oil—water emulsions was investigated. It is established that both amino acids and their salts (hydrochlorides) exhibit an antioxidant effect. The antioxidant action of amino acids increases with an increasing number of nitrogen atoms in the molecule. The amino group is a reactive center at which the process of oil oxidation in the emulsion is inhibited. Amino acids and their salts (hydrochlorides) act on the oil—water interface so as to accelerate the disintegration of lipid peroxide compounds in the water—oil system with the formation of molecular products.

Hydroxyl mechanism of the antimalarial effect of artemisinin and its analogs

Kinetic schemes for the intramolecular oxidation of four artemisinin analogs, which are used as drugs against malaria, were developed. Each stage of the kinetic scheme is characterized by the enthalpy, activation energy, and rate constant calculated using the model of intersecting parabolas. The competition of mono- and bimolecular radical reactions was taken into account when developing the schemes. The hydroperoxide groups are formed as a result of the intramolecular oxidation of these compounds and generate free radicals in the reaction with FeII. Among these free radicals, hydroxyl radicals play the key role, since their yield (nOH) correlates with the antimalarial activity of the peroxide compound. The efficiency of the drug (index IC50) exponentially depends on nOH and is expressed by the formula IC50(Artemisinin)/IC50(Compound) = 1.54·10−6exp(3.9nOH). The elementary reactions resulting in the generation of hydroxyl radicals are considered. It is supposed that DNA of a malaria parasite is the main biological target for hydroxyl radicals.

The oxidative and nitrosative stress defence network of Wolinella succinogenes: cytochrome c nitrite reductase mediates the stress response to nitrite, nitric oxide, hydroxylamine and hydrogen peroxide

Microorganisms employ diverse mechanisms to withstand physiological stress conditions exerted by reactive or toxic oxygen and nitrogen species such as hydrogen peroxide, organic hydroperoxides, superoxide anions, nitrite, hydroxylamine, nitric oxide or NO-generating compounds. This study identified components of the oxidative and nitrosative stress defence network of Wolinella succinogenes, an exceptional Epsilonproteobacterium that lacks both catalase and haemoglobins. Various gene deletion-insertion mutants were constructed, grown by either fumarate respiration or respiratory nitrate ammonification and subjected to disc diffusion, growth and viability assays under stress conditions. It was demonstrated that mainly two periplasmic multihaem c-type cytochromes, namely cytochrome c peroxidase and cytochrome c nitrite reductase (NrfA), mediated resistance to hydrogen peroxide. Two AhpC-type peroxiredoxin isoenzymes were shown to be involved in protection against different organic hydroperoxides. The phenotypes of two superoxide dismutase mutants lacking either SodB or SodB2 implied that both isoenzymes play important roles in oxygen and superoxide stress defence although they are predicted to reside in the cytoplasm and periplasm respectively. NrfA and a cytoplasmic flavodiiron protein (Fdp) were identified as key components of nitric oxide detoxification. In addition, NrfA (but not the hybrid cluster protein Hcp) was found to mediate resistance to hydroxylamine stress. The results indicate the presence of a robust oxidative and nitrosative stress defence network and identify NrfA as a multifunctional cytochrome c involved in both anaerobic respiration and stress protection.

Electrolytic aminated carbon materials for the electrocatalytic redox reactions of inorganic and organic compounds

Some kinds of amine groups can be introduced to the glassy carbon surface by the electrode oxidation of the carbon electrode surface in ammonium carbamate solution, and this amine groups modified electrode is named as an aminated glassy carbon electrode. The existences of not only primary amine but also secondary and tertially amines were confirmed by X ray photoelectron spectroscopy. The applications of the aminated carbon material for the electrocatalytic reductions of oxygen, hydrogen peroxide, and organic compounds such as quinones were carried out, and the effects of amination on the formation of electrocatalytic sites for many species were revealed. The electrocatalyzed cyclic voltammograms of metal ions and metal chelate compounds obtained by aminated glassy carbon electrodes are also discussed. Moreover, we intend to describe that the aminated carbon electrode can exhibit the large reduction waves of inorganic oxoacids such as N0 2− or bromide ion. The introduced functional groups containing nitrogen atom can change the distribution of the electron densities of the graphite carbon surface, and this specific electron distribution environment may generate the various electrocatalytic activities.

Effect of americium-241 on luminous bacteria. Role of peroxides

The effect of americium-241 ( 241Am), an alpha-emitting radionuclide of high specific activity, on luminous bacteria Photobacterium phosphoreum was studied. Traces of 241Am in nutrient media (0.16–6.67 kBq/L) suppressed the growth of bacteria, but enhanced luminescence intensity and quantum yield at room temperature. Lower temperature (4 °C) increased the time of bacterial luminescence and revealed a stage of bioluminescence inhibition after 150 h of bioluminescence registration start. The role of conditions of exposure the bacterial cells to the 241Am is discussed. The effect of 241Am on luminous bacteria was attributed to peroxide compounds generated in water solutions as secondary products of radioactive decay. Increase of peroxide concentration in 241Am solutions was demonstrated; and the similarity of 241Am and hydrogen peroxide effects on bacterial luminescence was revealed. The study provides a scientific basis for elaboration of bioluminescence-based assay to monitor radiotoxicity of alpha-emitting radionuclides in aquatic solutions.

Cross-Linking of Polymers: Kinetics and Transport Phenomena

The cross-linking process of a complex system was studied at elevated temperature. Partially hydrogenated poly(acrylonitrile-co-1,3-butadiene)/dicumyl peroxide compound was selected as a representative complex polymer/cross-linking agent system. On the basis of the mechanisms of cross-linking reactions, an expression relating reaction rates and population balance equations with rheologically determined concentration of cross-links was applied. Consequently the Eyring equation reflecting the effect of the self-diffusion on reaction rate constants was utilized and was further integrated into the classical Arrhenius equation for reaction rate constants. Diffusion coefficients acknowledging the mutual diffusion were estimated according to the free-volume theory, whereas thermodynamic properties governing the heat transfer, i.e. density, heat capacity, and thermal conductivity, were determined from independent measurements. Plateau storage modulus variation was monitored within the linear viscoelastic regime b...

Amine oxidases of the quinoproteins family: Their implication in the metabolic oxidation of xenobiotics

Copper amine oxidases (CuAOs) are ubiquitous enzymes, which play a vital role in the physiology and pathology of mammals in controlling the metabolism of various primary monoamines, diamines and polyamines of endogenous or xenobiotic origin. CuAOs, which belong to the quinoproteins family, possess two cofactors: tightly bound Cu(II) and a quinone residue, which catalyzes the oxidative deamination of primary amines with concomitant production of aldehyde, ammonia and hydrogen peroxide through a "ping-pong" mechanism. Interest in human enzymes of the CuAOs class has increased in recent years driven by the discovery that the human vascular adhesion protein-1 (VAP-1), which regulates leucocyte trafficking and glucose transport, is a CuAO enzyme. The activities of CuAOs are increased in various human disorders such as diabetes, Alzheimer's disease and many inflammation-associated diseases leading to the overproduction of toxic metabolites, especially hydrogen peroxide and aldehyde compounds. As most consequences are pathological, effective and selective inhibitors of CuAOs should be of great interest as therapeutic agents. Nevertheless, the utilization of CuAOs to generate enzymatic toxic products into cancer cells for selective in situ killing, deserves to be considered in cancer therapy. This paper briefly highlights recent progress in the study of physiological, pathological and molecular aspects of CuAOs in mammals. Furthermore, a small molecule, that mimics the metabolic activity of CuAOs toward endogenous and exogenous amines, is described because it could be used as a surrogate of enzymes for a preliminary screening of potential inhibitors of CuAO enzymes.

Characterization of structure and activity of garlic peroxidase (POX1B)

Structural characterization and study of the activity of new POX(1B) protein from garlic which has a high peroxidase activity and can be used as a biosensor for the detection of hydrogen peroxide and phenolic compounds were performed and compared with the findings for other heme peroxidases. The structure-function relationship was investigated by analysis of the spectroscopic properties and correlated to the structure determined by a new generation of high-performance hybrid mass spectrometers. The reactivity of the enzyme was analyzed by studies of the redox activity toward various ligands and the reactivity with various substrates. We demonstrated that, in the case of garlic peroxidase, the heme group is pentacoordinated, and has an histidine as a proximal ligand. POX(1B) exhibited a high affinity for hydrogen peroxide as well as various reducing cosubstrates. In addition, high enzyme specificity was demonstrated. The k(cat) and K(M) values were 411 and 400 mM(-1) s(-1) for 3,3',5,5'-tetramethylbenzidine and 2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid), respectively. Furthermore, the reduction of nitro compounds in the presence of POX(1B) was demonstrated by iron(II) nitrosoalkane complex assay. In addition, POX(1B) showed a great potential for application for drug metabolism since its ability to react with 1-nitrohexane in the presence of sodium dithionite was demonstrated by the appearance of a characteristic Soret band at 411 nm. The high catalytic efficiency obtained in the case of the new garlic peroxidase (POX(1B)) is suitable for the monitoring of different analytes and biocatalysis.

ChemInform Abstract: Thermal and Photochemical Decomposition of 9-Arylxanthen-9-yl Hydroperoxides and Peroxides.

The thermolysis and photolysis of a series of 9-arylxanthenyl hydroperoxides and peroxides have been investigated by means of differential scanning calorimetry, electron paramagnetic spectroscopy and product studies. These relatively stable peroxidic compounds were found to rearrange smoothly on being heated at temperatures > 120°C and on photolysis, respectively, through concerted reaction pathways. Photolysis of 9-hydroperoxy-9-phenylxanthene and di(9-phenylxanthen-9-yl) peroxide, respectively, have been shown by EPR spectroscopy to generate 9-phenylxanthenyl radicals which dimerise at low temperatures and reform the free radicals at ambient temperature.

Responses of growth and antioxidant systems in Carthamus tinctorius L. under water deficit stress

An investigation was carried out to find out the extent of changes occurred in two safflower (Carthamus tinctorius L.) cultivars in response to water deficit stress. Two safflower cultivars namely IL.111 and Isfahan were used for the study. Thirty days after sowing, plants were grown under soil moisture corresponding to 100, 85, 70 and 55% field capacity for next 30 days. Water deficit treatments significantly decreased the shoot length, shoot dry matter, root dry matter, relative growth rate, leaf relative water content (LRWC) and leaf water potential (ΨW), whereas root length, root-to-shoot ratio, lipid peroxidation and antioxidant compounds such as ascorbic acid (AA), α-tocopherol (α-Toc) and reduced glutathione (GSH) and superoxide dismutase (SOD, EC 1.15.1.1), catalase (CAT, EC 1.11.1.6), and peroxidase (POX, EC 1.11.1.7) activities were increased. Water deficit stressed plants maintained higher levels of compounds and scavenging enzymes. Significant differences were observed between cultivars and irrigation levels treatments. The cv. IL.111 could be considered more tolerant to water stress than cv. Isfahan, registering greater biomass, LRWC and leaf water potential (ΨW), associated with high antioxidant activity.

The influence of chemical composition on the saturated vapor pressure in biological motor fuels

Volatility fuels fraction of the estimated parameters and letkosti. Volatility characterizes the ability to switch fuels in vaporous state. Selecting indicators to assess the volatility depends on the chemical composition of fuel. The main measure letkosti etanolnogo fuel is vapor pressure. The most simple and cost-effective to improve cold start is putting in fuel lehkoletyuchyh components: butane, izopentanu, gas and other petroleum. It was investigated the influence of DEE on alcohol-gasoline blend, the results show that DEE positive impact on increasing vapor pressure to the desired minimum for starting the engine. But because the ether to 19%, then at such high levels can actively formed peroxide compounds, which is undesirable. Very promising is the use of propane-butane gas mixture as lehkoletyuchoyi gaseous component. Butanizovani spirit-petrol mixture can be recommended for use as alternative fuel vehicles after further study of their stability and himmotolohichnyh characteristics.

10.1007/s11494-008-2007-3

The kinetics of o-cresol oxidation with ozone in acetic anhydride was studied. It was shown that o-cresol was acylated in acetic anhydride to give o-cresyl acetate. Ozone attacks the C=C bonds of the aromatic ring of o-cresyl acetate to give unsaturated peroxide compounds. The composition of the oxidation products alters when the ozonation is carried out in the presence of catalytic amounts of sulfuric acid. Along with the products of the destructive oxidation of the aromatic ring, the methyl group oxidation products appeared as the acyl derivatives o-acetoxybenzyl alcohol and o-acetoxybenzaldehyde, a form that is more stable toward the action of ozone (10%). The addition of manganese(II) acetate to the reaction mixture increases the methyl group oxidation selectivity to 75%. The mechanism of the ozone reaction with o-cresol in acetic anhydride that explains the obtained results is discussed.

The impact of copper ions on growth, lipid peroxidation, and phenolic compound accumulation and localization in lentil ( Lens culinaris Medic.) seedlings

Changes in phenolics (PhC) measured as UV-absorbing compounds (UVAC) and their localization as well as growth, lipid peroxidation (TBARS level), H 2O 2 and Cu accumulation and other ions content in roots of two lentil cultivars (cv. Krak and cv. Tina) contrasting in Cu sensitivity were examined. The aim of this study was to reveal the importance of PhC in Cu tolerance. During Cu treatment, inhibition of growth and increases in lipid peroxidation in roots of both cultivars were observed, but the effects were more pronounced in cv. Tina (more sensitive) than in cv. Krak (less sensitive). Cu at 0.5 mM caused higher Cu and H 2O 2 accumulation, but lower K + content and UVAC levels in the root tips of cv. Tina. Opposite changes were recorded in cv. Krak. Fluorescence microscopic analyses confirmed greater PhC accumulation in cv. Krak (less sensitive) than in cv. Tina (more sensitive) after Cu treatment and showed that these compounds accumulated particularly in vacuoles and the cell wall. Taken together, these results show that, in spite of the high concentration of Cu-stimulated PhC accumulation in cv. Krak, it was not sufficient to counteract the amount of ROS generated by the metal. The role of PhC in different reactions to Cu stress in lentil roots is discussed.

Characterization of colored products formed during irradiation of aqueous solutions containing H 2O 2 and phenolic compounds

Irradiation of aqueous (pH = 5) mixtures containing hydrogen peroxide (1 mM) and phenolic compounds (10 mM) were found to produce visible light absorbing solutions over the course of several hours. The kinetics and products of these reactions were studied by UV–VIS absorbance, electrospray mass spectrometry, FTIR, fluorescence, and NMR and compared to humic-like substances commonly found in atmospheric particulate matter. It was determined the reactions leading to formation of color are quite general to this compound class, and the reactions proceeded more rapidly with hydroxyl or methoxy substitution ortho to the phenolic OH. However, para substitution generally slowed formation of colored compounds compared to the unsubstituted form. Mass spectrometry confirms compounds of several hundred Da formed in the reaction mixtures. The IR spectra of the reaction products bear similarity to that observed for authentic aerosol humic-like substances. The results indicate radical coupling of phenols and methoxylated phenols in tropospheric waters may contribute to humic-like particulate matter.

Novel perfluoropolyethers containing 2,2,4-trifluoro-5-trifluoromethoxy-1,3-dioxole blocks: synthesis and characterization

Peroxidic perfluoropolyethers (PFPEs) are industrial intermediates used by Solvay Solexis for the preparation of different classes of (per)fluoropolyethers (Fomblin ®, Galden ®, Solvera ®, Fluorolink ®). The chemistry of these peroxidic compounds has been recently exploited for the synthesis of novel PFPE block copolymers. In the present work we report the synthesis, the structural and physical–chemical characterization of block copolymers obtained by the reaction of peroxidic PFPEs with 2,2,4-trifluoro-5-trifluoromethoxy-1,3-dioxole, a cyclic homopolymerizable perfluoroolefin. These block copolymers combine the most attractive properties of the PFPEs, like the excellent lubrication, the high thermal stability and the optical transparency, with new specific properties which are related to the perfluorodioxolenic blocks.

Nanoporous Membranes with Mixed Nanoclusters for Raman-Based Label-Free Monitoring of Peroxide Compounds

Monitoring trace amounts of peroxide-based molecules is challenging because of the lack of common optical signatures (fluorescence or absorption in UV-vis range) or chemical functionality easily detectable with common routines. To overcome this issue, we suggest a photochemical decomposition approach followed by the analysis of chemical fragments by a fast, sensitive, and reliable Raman spectroscopic method. To facilitate this approach, we employed a novel design of surface-enhanced Raman scattering (SERS)-active nanoporous substrate based on porous alumina membranes decorated with mixed nanoclusters composed of gold nanorods and nanoparticles. The detectable amount of HMTD below 2 pg demonstrated here is about 3 orders of magnitude lower than the current limit of detection. We suggest that laser-induced photocatalytic decomposition onto nanoparticle clusters is critical for achieving label-free detection of unstable and nonresonant organic molecules.