Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 13 de 13
Filtrar
Mais filtros











Intervalo de ano de publicação
1.
J Neuroimmunol ; 340: 577145, 2020 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-31945593

RESUMO

Lavandula angustifolia (LaEO) essential oil has been widely used by aromatherapy in the treatment of various clinical conditions, with evidence of its analgesic and anti-inflammatory potential. Our results demonstrate that sixty-five substances were identified in LaEO. Among the compounds found, the major ones were linalool (30.61%) and linalyl acetate (20.36%). We found that LaEO inhalation reduces mechanical hyperalgesia in conditions of chronic inflammatory and neuropathic pain. Furthermore, this effect seems to be mediated by peripheral and central opioid and cannabinoid 2 receptors. The findings of the present study suggests that the LaEO inhalation is effective on the chronic pain treatment.


Assuntos
Hiperalgesia , Óleos Voláteis/farmacologia , Receptores de Canabinoides/metabolismo , Receptores Opioides/metabolismo , Animais , Modelos Animais de Doenças , Feminino , Hiperalgesia/metabolismo , Inflamação/metabolismo , Lavandula , Camundongos , Neuralgia/metabolismo , Extratos Vegetais/farmacologia
2.
Food Chem Toxicol ; 118: 557-565, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29886231

RESUMO

Antiinflammatory and antitumor activity has been reported in Passiflora edulis (yellow passion fruit) nevertheless the intrinsic mechanisms of action are not fully elucidated. The present study aimeds to perform a comparison between the antitumor activity involving the crude extract (HCE) and the supercritical fluid extract with ethanol as co-solvent (SFEtOH) from P. edulis f. flavicarpa Deg. The in vitro cytotoxicity was evaluated in MCF-7 cells, while the in vivo antitumor activity was assessed in male Balb/c mice inoculated with Ehrlich carcinoma cells. SFEtOH exhibited higher antitumor activity compared to HCE. Wherein, SFEtOH showed an EC50 of 264.6 µg/mL against MCF-7 cells as well as an increased inhibition of tumor growth of 48.5% (p < 0.001) in male Balb/c mice, thereby promoting an increased mice lifespan to approximately 42%. Moreover, SFEtOH caused lipid (p < 0.001) and protein (p < 0.001) oxidation by increasing glutathione redox cycle activity while decreased the thioredoxin reductase activity (p < 0.001). SFEtOH also induced oxidative DNA damage in Ehrlich ascites carcinoma (EAC) cells leading to G2/M cycle arrest and has increased apoptotic cells up to 48.2%. These data suggest that the probable mechanisms of antitumor effect are associated to the lipid, protein and DNA damage, leading to cell cycle arrest and triggering apoptosis via mitochondrial pathway, should be probable due to the presence of medium and long chain fatty acids such as lauric acid.


Assuntos
Antineoplásicos Fitogênicos/farmacologia , Apoptose/efeitos dos fármacos , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Ácidos Graxos/metabolismo , Estresse Oxidativo , Passiflora/química , Animais , Antineoplásicos Fitogênicos/isolamento & purificação , Biomarcadores , Ensaios de Seleção de Medicamentos Antitumorais , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Células MCF-7 , Masculino , Camundongos Endogâmicos BALB C , Ensaios Antitumorais Modelo de Xenoenxerto
3.
J Ethnopharmacol ; 217: 178-186, 2018 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-29462700

RESUMO

ETHNOPHARMACOLOGICAL RELEVANCE: Eugenia brasiliensis Lam. (Myrtaceae) is a Brazilian tree distributed throughout Atlantic rain forest, since Bahia until Santa Catarina state, and is popularly known as "grumixaba, grumixameira, cumbixaba, ibaporoiti, and cereja-brasileira". The bark and leaves of Eugenia brasiliensis are used in folk medicine as adstringent, diuretic, energizing, anti-rheumatic and anti-inflammatory. This study aimed at investigating the chemical composition, antinociceptive and anti-inflammatory effect of the hydroalcoholic extract of Eugenia brasiliensis (HEEb). MATERIAL AND METHODS: Chemical composition of the HEEb was determined by High Performance Liquid Chromatography/ESI-Mass Spectrometry (HPLC-ESI-MS/MS). The antinociceptive and anti-inflammatory effects of HEEb (30-300 mg/kg) was verified in mice after oral administration by intra-gastric gavage (i.g.) 60 min prior to experimentation. It was investigated whether HEEb decreases visceral pain and leukocyte migration induced by an intraperitoneal (i.p.) injection of acetic acid (0.6%). We also evaluated whether HEEb decreases nociceptive behavior induced by formalin (including paw edema and temperature), prostaglandin E2 (PGE2), histamine, and compound 48/80. Finally, we evaluated the effect of HEEb in the chronic inflammatory (mechanical and thermal hypersensitivity) pain induced by complete Freund's adjuvant (CFA), as well as quantifying the concentration of the pro-inflammatory cytokines TNF-α and IL-6 in the paw by ELISA method. RESULTS: Seven polyphenols were identified in HEEb by HPLC-ESI-MS/MS analysis. HEEb treatment alleviated nocifensive behavior and leukocyte migration caused by acetic acid. Moreover, HEEb also reduced the inflammatory pain and paw temperature induced by formalin, as well as it decreased nociceptive behavior induced by histamine and compound 48/80. Finally, acute and repeated treatment of animals with HEEb (100 mg/kg, i.g.) markedly reduced the mechanical and thermal (heat) hypersensitivity, besides decrease paw edema and temperature induced by CFA, and this effect was evident until the day 7. Moreover, repeated treatment with HEEb (100 mg/kg, i.g.) significantly reduced the levels of IL-6 and TNF-α in the paw when compared to the CFA group. CONCLUSIONS: This is the first report showing that HEEb presents antinociceptive and anti-inflammatory effects in the visceral and somatic inflammatory pain in mice, possibly involving the inhibition of histamine receptors and pro-inflammatory cytokines activated pathways. Our results are of interest because they support the use of Eugenia brasiliensis as a potential source of phytomedicine for inflammatory diseases and pain.


Assuntos
Analgésicos/farmacologia , Anti-Inflamatórios/farmacologia , Eugenia , Dor Nociceptiva/prevenção & controle , Extratos Vegetais/farmacologia , Dor Visceral/prevenção & controle , Analgésicos/isolamento & purificação , Animais , Anti-Inflamatórios/isolamento & purificação , Cromatografia Líquida de Alta Pressão , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Eugenia/química , Feminino , Mediadores da Inflamação/metabolismo , Interleucina-6/metabolismo , Camundongos , Dor Nociceptiva/induzido quimicamente , Dor Nociceptiva/metabolismo , Fitoterapia , Extratos Vegetais/isolamento & purificação , Plantas Medicinais , Espectrometria de Massas por Ionização por Electrospray , Espectrometria de Massas em Tandem , Fator de Necrose Tumoral alfa/metabolismo , Dor Visceral/induzido quimicamente , Dor Visceral/metabolismo
4.
An. acad. bras. ciênc ; 89(3): 1907-1915, July-Sept. 2017. tab
Artigo em Inglês | LILACS | ID: biblio-886748

RESUMO

ABSTRACT Many essential oils (EOs) of different plant species possess interesting antimicrobial effects on buccal bacteria and antioxidant properties. Eugenia klotzschiana Berg (pêra-do-cerrado, in Portuguese) is a species of Myrtaceae with restricted distribution in the Cerrado. The essential oils were extracted through the hydrodistillation technique using a modified Clevenger apparatus (2 hours) and chemically characterized by GC-MS. The major compounds were α-copaene (10.6 %) found in oil from leaves in natura, β-bisabolene (17.4 %) in the essential oil from dry leaves and α-(E)-bergamotene (29.9 %) in oil from flowers. The antioxidant activity of essential oils showed similarities in both methods under analysis (DPPH and ABTS˙+) and the results suggested moderate to high antioxidant activity. The antibacterial activity was evaluated by determining minimum inhibitory concentrations (MICs), using the microdilution method. MIC values below 400 µg/mL were obtained against Streptococcus salivarius (200 µg/mL), S. mutans (50 µg/mL), S. mitis (200 µg/mL) and Prevotella nigrescens (50 µg/mL). This is the first report of the chemical composition and antibacterial and antioxidant activities of the essential oils of E. klotzschiana. These results suggest that E. klotzschiana, a Brazilian plant, provide initial evidence of a new and alternative source of substances with medicinal interest.


Assuntos
Streptococcus/efeitos dos fármacos , Prevotella/efeitos dos fármacos , Folhas de Planta/química , Flores/química , Eugenia/química , Antibacterianos/farmacologia , Antioxidantes/farmacologia , Testes de Sensibilidade Microbiana , Cromatografia Gasosa-Espectrometria de Massas , Antibacterianos/isolamento & purificação , Antioxidantes/isolamento & purificação
5.
Rev. bras. farmacogn ; 27(4): 459-465, July-Aug. 2017. tab, graf
Artigo em Inglês | LILACS | ID: biblio-898693

RESUMO

ABSTRACT Eugenia brasiliensis Lam., Myrtaceae, is used in folk medicine for anti-inflammatory diseases such as arthritis and rheumatism. This study investigated the anti-inflammatory activity and phenolic profile of the crude hydroalcoholic extract and ethyl acetate fraction from E. brasiliensis leaves. Crude hydroalcoholic extract and the ethyl acetate fraction were analyzed by HPLC-ESI-MS/MS in comparison to standard phenolic compounds. The anti-inflammatory activity of the crude hydroalcoholic extract (1, 10 and 25 mg kg-1) and the ethyl acetate fraction (10, 25 and 50 mg kg-1) was evaluated in a swiss mouse model of acute pleurisy induced by carrageenan, being the total cell count, exudation and analysis of nitrite/nitrate the inflammation parameters. HPLC-ESI-MS/MS analysis revealed apigenin, catechin, galangin, isoquercetin, myricetin, quercetin and rutin. Crude hydroalcoholic extract and ethyl acetate fraction were effective in inhibiting cell migration in all tested doses. Crude hydroalcoholic extract was effective in inhibiting exudation only at the 10 mg kg-1 dose; ethyl acetate fraction was effective in all tested doses. Results for nitrite/nitrate levels reveals that only the ethyl acetate fraction was effective at the tested doses. This is the first report of the presence of isoquercetin, galangin and apigenin in this species. Results from the phytochemical analysis enhance the chemical knowledge of this species. In the future, together with more studies, validation of its popular use in inflammatory diseases is possible.

6.
J Ethnopharmacol ; 175: 30-8, 2015 Dec 04.
Artigo em Inglês | MEDLINE | ID: mdl-26344850

RESUMO

ETHNOPHARMACOLOGICAL RELEVANCE: Cedrus atlantica essential oil (CaEO) presents analgesic and anti-inflammatory sedative properties. However, it remains unknown whether CaEO alleviates acute postoperative pain. MATERIALS AND METHODS: Here, we investigated the effect of CaEO on postoperative pain and its mechanisms related to the descending pain control in Swiss males mice induced by a plantar incision surgery (PIS) in the hindpaw. RESULTS: Inhalation of CaEO (5', 30' or 60') markedly reduced mechanical hypersensitivity. This effect was prevented by pre-treatment with naloxone or p-chlorophenylalanine methyl ester (PCPA, 100mg/kg, i.p.)-induced depletion of serotonin. In addition, p-alpha-methyl-para-tyrosin (AMPT, 100mg/kg, i.p.)-induced depletion of norepinephrine, intraperitoneal injection of the α2-adrenergic receptor antagonist yohimbine (0.15 mg/kg, i.p.) or haloperidol (1mg/kg, i.p.) an antagonist of dopaminergic (D1 and D2) receptors prevented the effect of CaEO on hypersensitivity. CONCLUSIONS: These findings suggest that CaEO alleviates postoperative pain by activating the descending pain modulation pathways on the opioidergic, serotonergic, noradrenergic (α2-adrenergic) and dopaminergic (dopamine D1 and D2 receptors) systems.


Assuntos
Analgésicos/uso terapêutico , Cedrus , Hiperalgesia/tratamento farmacológico , Óleos Voláteis/uso terapêutico , Dor Pós-Operatória/tratamento farmacológico , Administração por Inalação , Antagonistas de Receptores Adrenérgicos alfa 2/farmacologia , Analgésicos/administração & dosagem , Animais , Comportamento Animal/efeitos dos fármacos , Modelos Animais de Doenças , Antagonistas de Dopamina/farmacologia , Fenclonina/análogos & derivados , Fenclonina/farmacologia , Pé/cirurgia , Haloperidol/farmacologia , Hiperalgesia/metabolismo , Masculino , Camundongos , Atividade Motora/efeitos dos fármacos , Naloxona/farmacologia , Antagonistas de Entorpecentes/farmacologia , Óleos Voláteis/administração & dosagem , Dor Pós-Operatória/metabolismo , Fitoterapia , Antagonistas da Serotonina/farmacologia , Ioimbina/farmacologia , alfa-Metiltirosina/farmacologia
7.
Talanta ; 123: 45-53, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24725863

RESUMO

The aim of this study was to develop a new multilayer coating with crosslinked quaternary ammonium chitosan (hydroxypropyltrimethyl ammonium chloride chitosan; HACC) and κ-carrageenan for use in capillary electrophoresis. A new semi-permanent multilayer coating was formed using the procedure developed and the method does not require the presence of polymers in the background electrolyte (BGE). The new capillary multilayer coating showed a cathodic electroosmotic flow (EOF) of around 30×10(-9) m(2) V(-1) s(-1) which is pH-independent in the range of pH 2 to 10. The enhanced EOF at low pH obtained contributed significantly to the development of a fast method of separation. The multilayer coating was then applied in the development of a fast separation method to determine betaine and methionine in pharmaceutical formulations by capillary zone electrophoresis (CZE). The BGE used to determine the betaine and methionine concentrations was composed of 10 mmol L(-1) tris(hydroxymethyl) aminomethane, 40 mmol L(-1) phosphoric acid and 10% (v/v) ethanol, at pH 2.1. A fused-silica capillary of 32 cm (50 µm ID×375 µm OD) was used in the experiments and samples and standards were analyzed employing the short-end injection procedure (8.5 cm effective length). The instrumental analysis time of the optimized method was 1.53 min (approx. 39 runs per hour). The validation of the proposed method for the determination of betaine and methionine showed good linearity (R(2)>0.999), adequate limit of detection (LOD <8 mg L(-1)) for the concentration in the samples and inter-day precision values lower than 3.5% (peak area and time migration). The results for the quantification of the amino acids in the samples determined by the CZE-UV method developed were statistically equal to those obtained with the comparative LC-MS/MS method according to the paired t-test with a confidence level of 95%.


Assuntos
Carragenina/química , Quitosana/análogos & derivados , Eletroforese Capilar/métodos , Compostos de Amônio Quaternário/química , Betaína/análise , Betaína/química , Sequência de Carboidratos , Quitosana/química , Cromatografia Líquida/métodos , Eletrólitos , Eletro-Osmose , Concentração de Íons de Hidrogênio , Metionina/análise , Metionina/química , Dados de Sequência Molecular , Estrutura Molecular , Reprodutibilidade dos Testes , Espectrometria de Massas em Tandem/métodos , Fatores de Tempo
8.
J Ethnopharmacol ; 145(3): 737-45, 2013 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-23237932

RESUMO

ETHNOPHARMACOLOGICAL RELEVANCE: Tabebuia avellanedae Lorentz ex Griseb is a plant employed in tropical America folk medicine for the treatment of several diseases, including depressive disorders. AIM OF THE STUDY: To investigate the ability of Tabebuia avellanedae ethanolic extract (EET) administered chronically to cause an antidepressant-like effect in the tail suspension test (TST), a predictive test of antidepressant activity, and to reverse behavioral (hyperactivity, anhedonic-like behavior and increased immobility time in the TST) and biochemical changes induced by olfactory bulbectomy (OB), a model of depression, in mice. MATERIALS AND METHODS: Mice were submitted to OB to induce depressive-related behaviors, which were evaluated in the open-field test (hyperactivity), splash test (loss of motivational and self-care behavior indicative of an anhedonic-like behavior) and TST (increased immobility time). Phosphorylation levels of Akt, GSK-3ß, ERK1/2 and CREB, as well as BDNF immunocontent, were evaluated in the hippocampus of bulbectomized mice or sham-operated mice treated for 14 days by p.o. route with EET or vehicle. RESULTS: EET (10 and 30mg/kg) given 14 days by p.o route to mice reduced the immobility time in the TST without altering locomotor activity, an indicative of an antidepressant-like effect. EET per se increased both CREB (Ser(133)) and GSK-3ß (Ser(9)) phosphorylation (at doses of 10-30 and 30mg/kg, respectively) in sham-operated mice. OB caused hyperactivity, loss of motivational and self-care behavior, increased immobility time in the TST and an increase in CREB and ERK1 phosphorylation, as well as BDNF immunocontent. EET abolished all these OB-induced alterations except the increment of CREB phosphorylation. Akt (Ser(473)) and ERK2 phosphorylation levels were not altered in any group. CONCLUSIONS: EET ability to abolish the behavioral changes induced by OB was accompanied by modulation of ERK1 and BDNF signaling pathways, being a promising target of EET. Results indicate that this plant could constitute an attractive strategy for the management of depressive disorders, once more validating the traditional use of this plant.


Assuntos
Antidepressivos/uso terapêutico , Depressão/tratamento farmacológico , Extratos Vegetais/uso terapêutico , Tabebuia , Animais , Antidepressivos/farmacologia , Comportamento Animal/efeitos dos fármacos , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Proteína de Ligação a CREB/metabolismo , Depressão/metabolismo , Depressão/fisiopatologia , Etanol/química , Feminino , Quinase 3 da Glicogênio Sintase/metabolismo , Glicogênio Sintase Quinase 3 beta , Hipocampo/efeitos dos fármacos , Hipocampo/metabolismo , Camundongos , Proteína Quinase 1 Ativada por Mitógeno/metabolismo , Proteína Quinase 3 Ativada por Mitógeno/metabolismo , Bulbo Olfatório/cirurgia , Fitoterapia , Casca de Planta , Extratos Vegetais/farmacologia , Proteínas Proto-Oncogênicas c-akt/metabolismo , Solventes/química
9.
J Cosmet Sci ; 62(5): 469-82, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-22152492

RESUMO

Our goal was to study the effect of Gp4G on skin tissues and unravel its intracellular action mechanisms. The effects of Gp4G formulation, a liposomic solution of Artemia salina extract, on several epidermal, depmal, and hair follicle structures were quantified. A 50% increase in hair length and a 30% increase in the number of papilla cells were explained by the changes in the telogen/anagen hair follicle phases. Increasing skin blood vessels and fibroblast activation modified collagen arrangement in dermal tissues. Imunohistochemical staining revealed expressive increases of versican (VER) deposition in the treated animals (68%). Hela and fibroblast cells were used as in vitro models. Gp4G enters both cell lines, with a hyperbolic saturation profile inducing an increase in the viabilities of Hela and fibroblast cells. Intracellular ATP and other nucleotides were quantified in Hela cells showing a 38% increase in intracellular ATP concentration and increases in the intracellular concentration of tri- , di- , and monophosphate nucleosides, changing the usual quasi-equilibrium state of nucleotide concentrations. We propose that this change in nucleotide equilibrium affects several biochemical pathways and explains the cell and tissue activations observed experimentally.


Assuntos
Fosfatos de Dinucleosídeos/farmacologia , Folículo Piloso/efeitos dos fármacos , Preparações para Cabelo/farmacologia , Animais , Artemia , Células Epiteliais/efeitos dos fármacos , Fibroblastos/efeitos dos fármacos , Cabelo/efeitos dos fármacos , Cabelo/crescimento & desenvolvimento , Folículo Piloso/crescimento & desenvolvimento , Células HeLa/efeitos dos fármacos , Humanos , Masculino , Camundongos , Modelos Animais , Ratos , Ratos Wistar , Pele/citologia , Pele/efeitos dos fármacos
10.
J Sep Sci ; 32(21): 3822-8, 2009 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-19877139

RESUMO

A method for the simultaneous determination of the stilbene resveratrol, four phenolic acids (syringic, coumaric, caffeic, and gallic acids), and five flavonoids (catechin, rutin, kaempferol, myricetin, and quercetin) in wine by CE was developed and validated. The CE electrolyte composition and instrumental conditions were optimized using 2(7-3) factorial design and response surface analysis, showing sodium tetraborate, MeOH, and their interaction as the most influential variables. The optimal electrophoretic conditions, minimizing the chromatographic resolution statistic values, consisted of 17 mmol/L sodium tetraborate with 20% methanol as electrolyte, constant voltage of 25 kV, hydrodynamic injection at 50 mbar for 3 s, and temperature of 25 degrees C. The R(2) values for linearity varied from 0.994 to 0.999; LOD and LOQ were 0.1 to 0.3 mg/L and 0.4 to 0.8 mg/L, respectively. The RSDs for migration time and peak area obtained from ten consecutive injections were less than 2% and recoveries varied from 97 to 102%. The method was applied to 23 samples of inexpensive Brazilian wines, showing wide compositional variation.


Assuntos
Eletroforese Capilar/métodos , Flavonoides/análise , Hidroxibenzoatos/análise , Fenóis/análise , Vinho/análise , Brasil , Limite de Detecção , Polifenóis , Reprodutibilidade dos Testes , Resveratrol , Estilbenos/análise
11.
Talanta ; 79(2): 222-8, 2009 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-19559869

RESUMO

A biosensor based on the ionic liquid, 1-n-butyl-3-methylimidazolium hexafluorophosphate containing dispersed iridium nanoparticles (Ir-BMI.PF(6)) and polyphenol oxidase was constructed. This enzyme was obtained from the sugar apple (Annona squamosa), immobilized in chitosan ionically crosslinked with oxalate. The biosensor was used for determination of chlorogenic acid by square wave voltammetry. The polyphenol oxidase catalyzes the oxidation of chlorogenic acid to the corresponding o-quinone, which is electrochemically reduced back to this substance at +0.25V vs. Ag/AgCl. Under optimized operational conditions the chlorogenic acid concentration was linear in the range of 3.48x10(-6) to 4.95x10(-5)mol L(-1) with a detection limit of 9.15x10(-7)mol L(-1). The biosensor was applied in the determination of chlorogenic acid in organic and decaffeinated coffee and the results compared with those obtained using the capillary electrophoresis method. The recovery study for chlorogenic acid in these samples gave values of 93.2-105.7%.


Assuntos
Técnicas Biossensoriais/métodos , Catecol Oxidase , Ácido Clorogênico/análise , Café/química , Enzimas Imobilizadas , Líquidos Iônicos , Irídio , Malus/enzimologia , Nanopartículas/química
12.
J Phys Chem B ; 112(46): 14373-8, 2008 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-18582111

RESUMO

The rate of specific hydrogen ion-catalyzed hydrolysis of 2-( p-heptoxyphenyl)-1,3-dioxolane and acid-base equilibrium of 4-carboxy-1-n-dodecylpyridinium in zwitterionic micelles of SB3-14, C14H29NMe2+(CH2)3SO3(-) are controlled by NaClO4, which induces anionic character and uptake of H3O+ in the micelles. Other salts, e.g., NaF, NaCl, NaBr, NaNO3, NaI, NaBF4, have similar, but smaller, effects on the uptake of H3O+. Salt effects upon zeta potentials of SB3-14 micelles, estimated by capillary electrophoresis, are anion specific, and the anion order is similar to that of the rates of acid hydrolysis and of acid-base equilibria. Fluorescence quenching shows that the micellar aggregation number is not very sensitive to added salts, consistent with electrophoretic evidence. These specific anion effects follow the Hofmeister series and are related to anion hydration free energies.


Assuntos
Ânions/química , Betaína/análogos & derivados , Cátions/química , Micelas , Betaína/química , Eletroforese Capilar , Eletricidade Estática
13.
Chem Res Toxicol ; 21(4): 879-87, 2008 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-18361509

RESUMO

Diacetyl, like other alpha-dicarbonyl compounds, is reportedly cytotoxic and genotoxic. A food and cigarette contaminant, it is related with alcohol hepatotoxicity and lung disease. Peroxynitrite is a potent oxidant formed in vivo by the diffusion-controlled reaction of the superoxide radical anion with nitric oxide, which is able to form adducts with carbon dioxide and carbonyl compounds. Here, we investigate the nucleophilic addition of peroxynitrite to diacetyl forming acetyl radicals, whose reaction with molecular oxygen leads to acetate. Peroxynitrite is shown to react with diacetyl in phosphate buffer (bell-shaped pH profile with maximum at 7.2) at a very high rate constant ( k 2 = 1.0 x 10 (4) M (-1) s (-1)) when compared with monocarbonyl substrates ( k 2 < 10 (3) M (-1) s (-1)). Phosphate ions (100-500 mM) do not affect the rate of spontaneous peroxynitrite decay, but the H 2PO 4 (-) anion catalyzes the nucleophilic addition of the peroxynitrite anion to diacetyl. The intermediacy of acetyl radicals is suggested by a three-line spectrum ( a N = a H = 0.83 mT) obtained by EPR spin trapping of the reaction mixture with 2-methyl-2-nitrosopropane. The peroxynitrite reaction is accompanied by concentration-dependent oxygen uptake. Stoichiometric amounts of acetate from millimolar amounts of peroxynitrite and diacetyl were obtained under nonlimiting conditions of dissolved oxygen. In the presence of either l-histidine or 2'-deoxyguanosine, the peroxynitrite/diacetyl system afforded the corresponding acetylated molecules identified by HPLC-MS ( n ). These studies provide evidence that the peroxynitrite/diacetyl reaction yields acetyl radicals and raise the hypothesis that protein and DNA nonenzymatic acetylation may occur in cells and be implicated in aging and metabolic disorders in which oxygen and nitrogen reactive species are putatively involved.


Assuntos
Desoxiguanosina/química , Diacetil/química , Histidina/química , Ácido Peroxinitroso/química , Acetilação , Oxigênio/química
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA