Base de dados : MEDLINE
Pesquisa : D01.339 [Categoria DeCS]
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  1 / 31547 MEDLINE  
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PMID:29386447
Autor:Mori T; Sawaguchi T
Endereço:Department of Pharmacology, Hoshi University School of Pharmacy and Pharmaceutical Sciences.
Título:[Underlying Mechanisms of Methamphetamine-Induced Self-Injurious Behavior and Lethal Effects in Mice].
Fonte:Nihon Eiseigaku Zasshi; 73(1):51-56, 2018.
ISSN:1882-6482
País de publicação:Japan
Idioma:jpn
Resumo:Relatively high doses of psychostimulants induce neurotoxicity on the dopaminergic system and self-injurious behavior (SIB) in rodents. However the underlying neuronal mechanisms of SIB remains unclear. Dopamine receptor antagonists, N-methyl-D-aspartic acid (NMDA) receptor antagonists, Nitric Oxide Synthase (NOS) inhibitors and free radical scavengers significantly attenuate methamphetamine-induced SIB. These findings indicate that activation of dopamine as well as NMDA receptors followed by radical formation and oxidative stress, especially when mediated by NOS activation, is associated with methamphetamine-induced SIB. On the other hand, an increase in the incidence of polydrug abuse is a major problem worldwide. Coadministered methamphetamine and morphine induced lethality in more than 80% in mice, accompanied by an increase in the number of poly (ADP-ribose) polymerase (PARP)-immunoreactive cells in the heart, kidney and liver. The lethal effect and the increase in the incidence of rupture or PARP-immunoreactive cells induced by the coadministration of methamphetamine and morphine were significantly attenuated by pretreatment with a phospholipase A2 inhibitor or a radical scavenger, or by cooling of body from 30 to 90 min after drug administration. These results suggest that free radicals play an important role in the increased lethality induced by the coadministration of methamphetamine and morphine. Therefore, free radical scavengers and cooling are beneficial for preventing death that is induced by the coadministration of methamphetamine and morphine. These findings may help us better understand for masochistic behavior, which is a clinical phenomenon on SIB, as well as polydrug-abuse-induced acute toxicity.
Tipo de publicação: JOURNAL ARTICLE; REVIEW
Nome de substância:0 (Central Nervous System Stimulants); 0 (Dopamine Antagonists); 0 (Free Radical Scavengers); 0 (Free Radicals); 0 (Receptors, N-Methyl-D-Aspartate); 44RAL3456C (Methamphetamine); 76I7G6D29C (Morphine)


  2 / 31547 MEDLINE  
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PMID:29410988
Autor:Ribar A; Huber SE; Smialek MA; Tanzer K; Neustetter M; Schürmann R; Bald I; Denifl S
Endereço:Institute for Ion Physics and Applied Physics and Center of Molecular Biosciences Innsbruck, Leopold Franzens University of Innsbruck, Technikerstr. 25, 6020 Innsbruck, Austria. stephan.denifl@uibk.ac.at.
Título:Hydroperoxyl radical and formic acid formation from common DNA stabilizers upon low energy electron attachment.
Fonte:Phys Chem Chem Phys; 20(8):5578-5585, 2018 Feb 21.
ISSN:1463-9084
País de publicação:England
Idioma:eng
Resumo:2-Amino-2-(hydroxymethyl)-1,3-propanediol (TRIS) and ethylenediaminetetraacetic acid (EDTA) are key components of biological buffers and are frequently used as DNA stabilizers in irradiation studies. Such surface or liquid phase studies are done with the aim to understand the fundamental mechanisms of DNA radiation damage and to improve cancer radiotherapy. When ionizing radiation is used, abundant secondary electrons are formed during the irradiation process, which are able to attach to the molecular compounds present on the surface. In the present study we experimentally investigate low energy electron attachment to TRIS and methyliminodiacetic acid (MIDA), an analogue of EDTA, supported by quantum chemical calculations. The most prominent dissociation channel for TRIS is through hydroperoxyl radical formation, whereas the dissociation of MIDA results in the formation of formic and acetic acid. These compounds are well-known to cause DNA modifications, like strand breaks. The present results indicate that buffer compounds may not have an exclusive protecting effect on DNA as suggested previously.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:0 (Formates); 0 (Free Radicals); 0 (Peroxides); 0YIW783RG1 (formic acid); 9007-49-2 (DNA)


  3 / 31547 MEDLINE  
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PMID:28467350
Autor:Santos HFD; Campos JF; Santos CMD; Balestieri JBP; Silva DB; Carollo CA; de Picoli Souza K; Estevinho LM; Dos Santos EL
Endereço:Research group on Biotechnology and Bioprospecting Applied to Metabolism (GEBBAM), Federal University of Grande Dourados, Rodovia Dourados Itahum, Km 12, 79804-970 Dourados, MS, Brazil. helderspk@gmail.com.
Título:Chemical Profile and Antioxidant, Anti-Inflammatory, Antimutagenic and Antimicrobial Activities of Geopropolis from the Stingless Bee Melipona orbignyi.
Fonte:Int J Mol Sci; 18(5), 2017 May 03.
ISSN:1422-0067
País de publicação:Switzerland
Idioma:eng
Resumo:Geopropolis is a resin mixed with mud, produced only by stingless bees. Despite being popularly known for its medicinal properties, few scientific studies have proven its biological activities. In this context, the objective of this study was to determine the chemical composition and antioxidant, anti-inflammatory, antimutagenic and antimicrobial activities of the geopropolis. The hydroalcoholic extract of geopropolis (HEGP) was prepared and its chemical composition determined by high performance liquid chromatography coupled to diode array detector and mass spectrometry (HPLC-DAD-MS). The antioxidant activity was determined by the capture of free radicals and inhibition of lipid peroxidation in human erythrocytes. The anti-inflammatory activity was evaluated by the inhibition of the hyaluronidase enzyme and the antimutagenic action was investigated in colonies. The antimicrobial activities were determined against bacteria and yeasts, isolated from reference strains and hospital origin. The chemical composition of HEGP included flavonoids, derivatives of glycosylated phenolic acids and terpenoids. HEGP showed high antioxidant activity, it inhibited the activity of the inflammatory enzyme hyaluronidase and reduced the mutagenic effects in . In relation to the antimicrobial activity, it promoted the death of all microorganisms evaluated. In conclusion, this study reveals for the first time the chemical composition of the HEGP of and demonstrates its pharmacological properties.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:0 (Anti-Infective Agents); 0 (Anti-Inflammatory Agents); 0 (Antioxidants); 0 (Flavonoids); 0 (Free Radicals); 0 (Hydroxybenzoates); 0 (Mutagens); 29656-58-4 (phenolic acid); 9009-62-5 (Propolis); 9H154DI0UP (Ethyl Methanesulfonate); EC 3.2.1.35 (Hyaluronoglucosaminidase)


  4 / 31547 MEDLINE  
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PMID:29376307
Autor:Nilova LP; Pilipenko TV
Título:[Evaluation of antioxidant properties of enriched bakery products in experiment on laboratory animals].
Fonte:Vopr Pitan; 85(6):39-47, 2016.
ISSN:0042-8833
País de publicação:Russia (Federation)
Idioma:rus
Resumo:The purpose was to study the effect of enriched bakery products in the diet of rats on indicators of prooxidant-antioxidant system of blood serum. Experiment was carried out on male Wistar rats with initial weight 140-180 g. After a quarantine during the preparatory period rats for 14 days were accustomed to the partial (50%) replacement of the standard diet by bakery products with standard compound­ing. Then, 7 groups of rats were formed: the 1st group of rats (control group, n=10) continued to receive bakery products of a standard composition; groups with the 2nd on 7th (experimental, n=8 in everyone) received enriched bakery products: the 2nd group - with blueberry powder; the 3rd group - with mountain ash powder; the 4th group - with sea-buckthorn powder; the 5th group - with flour of a pine nut; the 6th group - with rice bran oil; the 7th group - with pumpkin oil. The intensity of free radical oxidation and antioxidant activity (by chemiluminescence method), activity of superoxide dismutase and level of secondary oxidation products reacted with thiobarbituric acid (by spectrophotometry) were monitored in rat blood serum. It has been shown that the use of bakery products with different compounding in the animal diet had different effects on indicators of prooxidant-antioxidant system of blood serum. Bakery products containing sea buckthorn pomace powder, flour of pine nut and rice bran oil reduced intensity of free radical oxidation in rat blood serum by 36.0, 24.6 and 18.8%, respectively. It is suggested that bakery products containing flour of pine nut products brake a free radical oxidation in rat blood serum in case of simultaneous content of natural antioxidants and melanoidins. The anthocyanins of powder from blueberry berries can render antioxidant effect and slow down formation of by-products of oxidation. No statistically significant change on indicators of prooxidant-antioxidant system of blood serum of rats treated with bakery products with rowan powder or pumpkin oil was found, that may be due to animal refusal to eat such products.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:0 (Antioxidants); 0 (Free Radicals)


  5 / 31547 MEDLINE  
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PMID:28992485
Autor:Mercado DF; Bracco LLB; Arques A; Gonzalez MC; Caregnato P
Endereço:Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA), CCT-La Plata-CONICET, Universidad Nacional de La Plata, Casilla de Correo 16, Sucursal 4, 1900, La Plata, Argentina.
Título:Reaction kinetics and mechanisms of organosilicon fungicide flusilazole with sulfate and hydroxyl radicals.
Fonte:Chemosphere; 190:327-336, 2018 Jan.
ISSN:1879-1298
País de publicação:England
Idioma:eng
Resumo:Flusilazole is an organosilane fungicide used for treatments in agriculture and horticulture for control of diseases. The reaction kinetics and mechanism of flusilazole with sulfate and hydroxyl radicals were studied. The rate constant of the radicals with the fungicide were determined by laser flash photolysis of peroxodisulfate and hydrogen peroxide. The results were 2.0 × 10 s M for the reaction of the fungicide with HO and 4.6 × 10 s M for the same reaction with SO radicals. The absorption spectra of organic intermediates detected by laser flash photolysis of S O with flusilazole, were identified as α-aminoalkyl and siloxyl radicals and agree very well with those estimated employing the time-dependent density functional theory with explicit account for bulk solvent effects. In the continuous photolysis experiments, performed by photo-Fenton reaction of the fungicide, the main degradation products were: (bis(4-fluorophenyl)-hydroxy-methylsilane) and the non-toxic silicic acid, diethyl bis(trimethylsilyl) ester, in ten and twenty minutes of reaction, respectively.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:0 (Free Radicals); 0 (Fungicides, Industrial); 0 (Silanes); 0 (Sulfates); 0 (Triazoles); 3352-57-6 (Hydroxyl Radical); BBX060AN9V (Hydrogen Peroxide); F3WG2VVD87 (flusilazole)


  6 / 31547 MEDLINE  
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PMID:28668640
Autor:Mak PJ; Denisov IG
Endereço:Department of Chemistry, Saint Louis University, St. Louis, MO, United States. Electronic address: makp@slu.edu.
Título:Spectroscopic studies of the cytochrome P450 reaction mechanisms.
Fonte:Biochim Biophys Acta; 1866(1):178-204, 2018 01.
ISSN:0006-3002
País de publicação:Netherlands
Idioma:eng
Resumo:The cytochrome P450 monooxygenases (P450s) are thiolate heme proteins that can, often under physiological conditions, catalyze many distinct oxidative transformations on a wide variety of molecules, including relatively simple alkanes or fatty acids, as well as more complex compounds such as steroids and exogenous pollutants. They perform such impressive chemistry utilizing a sophisticated catalytic cycle that involves a series of consecutive chemical transformations of heme prosthetic group. Each of these steps provides a unique spectral signature that reflects changes in oxidation or spin states, deformation of the porphyrin ring or alteration of dioxygen moieties. For a long time, the focus of cytochrome P450 research was to understand the underlying reaction mechanism of each enzymatic step, with the biggest challenge being identification and characterization of the powerful oxidizing intermediates. Spectroscopic methods, such as electronic absorption (UV-Vis), electron paramagnetic resonance (EPR), nuclear magnetic resonance (NMR), electron nuclear double resonance (ENDOR), Mössbauer, X-ray absorption (XAS), and resonance Raman (rR), have been useful tools in providing multifaceted and detailed mechanistic insights into the biophysics and biochemistry of these fascinating enzymes. The combination of spectroscopic techniques with novel approaches, such as cryoreduction and Nanodisc technology, allowed for generation, trapping and characterizing long sought transient intermediates, a task that has been difficult to achieve using other methods. Results obtained from the UV-Vis, rR and EPR spectroscopies are the main focus of this review, while the remaining spectroscopic techniques are briefly summarized. This article is part of a Special Issue entitled: Cytochrome P450 biodiversity and biotechnology, edited by Erika Plettner, Gianfranco Gilardi, Luet Wong, Vlada Urlacher, Jared Goldstone.
Tipo de publicação: JOURNAL ARTICLE; RESEARCH SUPPORT, N.I.H., EXTRAMURAL; REVIEW
Nome de substância:0 (Free Radicals); 42VZT0U6YR (Heme); 9035-51-2 (Cytochrome P-450 Enzyme System); E1UOL152H7 (Iron); PDC6A3C0OX (Glycerol); S88TT14065 (Oxygen)


  7 / 31547 MEDLINE  
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PMID:29361219
Autor:Agostini A; Palm DM; Paulsen H; Carbonera D
Endereço:Department of Chemical Sciences, University of Padova , Via Marzolo 1, 35131 Padova, Italy.
Título:Accessibility of Protein-Bound Chlorophylls Probed by Dynamic Electron Polarization.
Fonte:J Phys Chem Lett; 9(3):672-676, 2018 Feb 01.
ISSN:1948-7185
País de publicação:United States
Idioma:eng
Resumo:The possibility to probe the accessibility of sites of proteins represents an important point to explore their interactions with specific substrates in solution. The dynamic electron polarization of nitroxide radicals induced by excited triplet states of organic molecules is a phenomenon that is known to occur in aqueous solutions. The interaction within the radical-triplet pair causes a net emissive dynamic electron polarization of the nitroxide radical, that can be detected by means of time-resolved electron paramagnetic resonance (TR-EPR) spectroscopy. We have exploited this effect to prove the accessibility of chlorophylls bound to a protein, namely, the water-soluble chlorophyll protein WSCP. The results have important implications for topological studies in macromolecules.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:0 (Free Radicals); 0 (Nitrogen Oxides); 0 (Proteins); 1406-65-1 (Chlorophyll); GFQ4MMS07W (nitroxyl)


  8 / 31547 MEDLINE  
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PMID:28463479
Autor:Hong CY; Ryu SH; Jeong H; Lee SS; Kim M; Choi IG
Endereço:Division of Wood Chemistry & Microbiology, Department of Forest Products, National Institute of Forest Science , Seoul, Republic of Korea.
Título:Phanerochaete chrysosporium Multienzyme Catabolic System for in Vivo Modification of Synthetic Lignin to Succinic Acid.
Fonte:ACS Chem Biol; 12(7):1749-1759, 2017 Jul 21.
ISSN:1554-8937
País de publicação:United States
Idioma:eng
Resumo:Whole cells of the basidiomycete fungus Phanerochaete chrysosporium (ATCC 20696) were applied to induce the biomodification of lignin in an in vivo system. Our results indicated that P. chrysosporium has a catabolic system that induces characteristic biomodifications of synthetic lignin through a series of redox reactions, leading not only to the degradation of lignin but also to its polymerization. The reducing agents ascorbic acid and α-tocopherol were used to stabilize the free radicals generated from the ligninolytic process. The application of P. chrysosporium in combination with reducing agents produced aromatic compounds and succinic acid as well as degraded lignin polymers. P. chrysosporium selectively catalyzed the conversion of lignin to succinic acid, which has an economic value. A transcriptomic analysis of P. chrysosporium suggested that the bond cleavage of synthetic lignin was caused by numerous enzymes, including extracellular enzymes such as lignin peroxidase and manganese peroxidase, and that the aromatic compounds released were metabolized in both the short-cut and classical tricarboxylic acid cycles of P. chrysosporium. In conclusion, P. chrysosporium is suitable as a biocatalyst for lignin degradation to produce a value-added product.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:0 (Free Radicals); 0 (Multienzyme Complexes); 0 (Nitrobenzenes); 9005-53-2 (Lignin); AB6MNQ6J6L (Succinic Acid); E57JCN6SSY (nitrobenzene); PQ6CK8PD0R (Ascorbic Acid); R0ZB2556P8 (Tocopherols)


  9 / 31547 MEDLINE  
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Texto completo SciELO Brasil
PMID:29186248
Autor:Addor FAS
Endereço:Private clinic - São Paulo (SP), Brazil.
Título:Antioxidants in dermatology.
Fonte:An Bras Dermatol; 92(3):356-362, 2017 May-Jun.
ISSN:1806-4841
País de publicação:Brazil
Idioma:eng
Resumo:The skin cells continuously produce, through cellular respiration, metabolic processes or under external aggressions, highly reactive molecules oxidation products, generally called free radicals. These molecules are immediately neutralized by enzymatic and non-enzymatic systems in a physiological and dynamic balance. In situations where this balance is broken, various cellular structures, such as the cell membrane, nuclear or mitochondrial DNA may suffer structural modifications, triggering or worsening skin diseases. several substances with alleged antioxidant effects has been offered for topical or oral use, but little is known about their safety, possible associations and especially their mechanism of action. The management of topical and oral antioxidants can help dermatologist to intervene in the oxidative processes safely and effectively, since they know the mechanisms, limitations and potential risks of using these molecules as well as the potential benefits of available associations.
Tipo de publicação: JOURNAL ARTICLE; REVIEW
Nome de substância:0 (Antioxidants); 0 (Free Radicals)


  10 / 31547 MEDLINE  
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PMID:28745873
Autor:Nauser T; Gebicki JM
Endereço:Department of Chemistry and Applied Biosciences, Swiss Federal Institute of Technology , Zurich CH8093, Switzerland.
Título:Physiological Concentrations of Ascorbate Cannot Prevent the Potentially Damaging Reactions of Protein Radicals in Humans.
Fonte:Chem Res Toxicol; 30(9):1702-1710, 2017 09 18.
ISSN:1520-5010
País de publicação:United States
Idioma:eng
Resumo:The principal initial biological targets of free radicals formed under conditions of oxidative stress are the proteins. The most common products of the interaction are carbon-centered alkyl radicals which react rapidly with oxygen to form peroxyl radicals and hydroperoxides. All these species are reactive, capable of propagating the free radical damage to enzymes, nucleic acids, lipids, and endogenous antioxidants, leading finally to the pathologies associated with oxidative stress. The best chance of preventing this chain of damage is in early repair of the protein radicals by antioxidants. Estimate of the effectiveness of the physiologically significant antioxidants requires knowledge of the antioxidant tissue concentrations and rate constants of their reaction with protein radicals. Previous studies by pulse radiolysis have shown that only ascorbate can repair the Trp and Tyr protein radicals before they form peroxyl radicals under physiological concentrations of oxygen. We have now extended this work to other protein C-centered radicals generated by hydroxyl radicals because these and many other free radicals formed under oxidative stress can produce secondary radicals on virtually any amino acid residue. Pulse radiolysis identified two classes of rate constants for reactions of protein radicals with ascorbate, a faster one in the range (9-60) × 10 M s and a slow one with a range of (0.5-2) × 10 M s . These results show that ascorbate can prevent further reactions of protein radicals only in the few human tissues where its concentration exceeds about 2.5 mM.
Tipo de publicação: JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
Nome de substância:0 (Free Radicals); 0 (Insulin); 0 (Nitrogen Oxides); 0 (Proteins); 0 (Serum Albumin); 42HK56048U (Tyrosine); 8DUH1N11BX (Tryptophan); EC 3.2.1.17 (Muramidase); PQ6CK8PD0R (Ascorbic Acid)



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