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1.
Food Chem ; 335: 127638, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-32736158

RESUMO

Using natural antioxidants instead of synthetics ones has been the tendency for retarding the oil deterioration during repeated deep frying process. Concerning this, the comparison between synthetic tertiarybutyl hydroquinone (TBHQ) and rosemary-based antioxidants in frying French fries was hereby evaluated. The quality and stability of frying oils with rosemary-based antioxidants showed higher efficiency than TBHQ regarding oxidation parameters (i.e., chemical indices, sensory, etc.), where rosmarinic acid (RA) was the most effective, followed by rosemary extracts (RE) and carnosic acid (CA). LF-NMR results were highly correlated (R2 = 0.909-0.998) to the change in physicochemical properties tested, where RA could effectively regulate the relaxation spectrum (T2) change and decrease single component relaxation time (T2W). The PCA graph of NIRS also revealed the dynamic change of antioxidant effectiveness in accordance with that obtained by chemical methods. Hence, both LF-NMR and NIRS can be expected as rapid and efficient methods for future monitoring the frying process.


Assuntos
Antioxidantes/química , Culinária , Temperatura Alta , Hidroquinonas/química , Rosmarinus/química , Solanum tuberosum/química , Óleo de Soja/química , Oxirredução
2.
SAR QSAR Environ Res ; 31(5): 347-371, 2020 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-32460542

RESUMO

Two simple and reliable correlations are introduced for the prediction of emission and absorption of porphyrins and their derivatives, i.e. metalloporphyrins and ligand coordinated metalloporphyrins. They can be used to sense the extracted precious metals. The proposed models require only simple structural parameters such as the number of carbon, metal and metal-free molecular fragments of desirable porphyrins or their derivatives. Since the proposed models depend on molecular structures of the desired compounds, they can be easily applied for complex molecular structures. Experimental data of 272 porphyrin derivatives were used to derive and test the novel models for the assessment of their emission (Em.) and absorption (Abs.) values in three solvents namely dichloromethane, toluene and chloroform. The values of the coefficients of determination (r 2) for the training set (183 compounds) in dichloromethane and three different test sets, corresponding to the three mentioned solvents, for the emission and absorption correlations were greater than 0.70. The calculated values of the root-mean-square error (RMSE) for the training sets of Em. and Abs. correlations were equal to 7.56 and 4.86 nm, respectively. Further statistical parameters also confirm the high reliability of the new models.


Assuntos
Quelantes/química , Porfirinas/química , Relação Quantitativa Estrutura-Atividade , Solventes/química , Clorofórmio/química , Hidroquinonas/química , Ligantes , Substâncias Macromoleculares/química , Metais Pesados/química , Cloreto de Metileno/química
3.
Chem Asian J ; 15(7): 1022-1024, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-32034862

RESUMO

We have demonstrated B2 pin2 as superior deoxidizing agent for the reductive deoxygenation of quinol derivatives under basic conditions. A wide range of highly functionalized phenols were obtained in good yields including a complex drug molecule, which revealed the high functional group tolerance of this protocol.


Assuntos
Hidrocarbonetos Aromáticos/química , Hidroquinonas/química , Oxigênio/química , Derivados de Benzeno/química , Compostos de Boro/química , Oxirredução , Fenóis
4.
Food Chem ; 315: 126197, 2020 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-32018079

RESUMO

Two novel lipophilic derivatives of the natural olive oil phenol, hydroxytyrosol (HT), were synthesized using 3,4-dihydroxyphenylacetic acid as starting material. Their antioxidant activities and kinetics compared to HT and TBHQ were assessed by Rancimat, Schaal Oven, 2,2-diphenyl-1-picrylhydrazyl (DPPH) and deep-frying methods. All experiments, including kinetic data analysis based on the Arrhenius equation, utilized in assessing antioxidant activity except the DPPH assay revealed that the new lipophilic HT derivatives exhibited much stronger antioxidant activity than hydroxytyrosol. Tert-butylhydroquinone exhibited stronger antioxidant activity in bulk oil at 65 °C than the new HT derivatives, but showed much lower activity at higher temperatures (>110 °C). This demonstrates that the introduction of bulky alkyl moiety to the ortho-diphenolic structure of HT increased its antioxidant activity. It can be concluded that the new lipophilic HT derivatives satisfy industrial demands for bioactive compounds with strong antioxidant potential at high temperatures.


Assuntos
Antioxidantes/química , Hidroquinonas/química , Álcool Feniletílico/análogos & derivados , Ácido 3,4-Di-Hidroxifenilacético/química , Antioxidantes/síntese química , Culinária , Cinética , Azeite de Oliva/química , Álcool Feniletílico/química , Óleo de Soja/química , Relação Estrutura-Atividade , Temperatura
5.
Proc Natl Acad Sci U S A ; 117(2): 872-876, 2020 01 14.
Artigo em Inglês | MEDLINE | ID: mdl-31888984

RESUMO

Virtually all proton-pumping terminal respiratory oxygen reductases are members of the heme-copper oxidoreductase superfamily. Most of these enzymes use reduced cytochrome c as a source of electrons, but a group of enzymes have evolved to directly oxidize membrane-bound quinols, usually menaquinol or ubiquinol. All of the quinol oxidases have an additional transmembrane helix (TM0) in subunit I that is not present in the related cytochrome c oxidases. The current work reports the 3.6-Å-resolution X-ray structure of the cytochrome aa 3 -600 menaquinol oxidase from Bacillus subtilis containing 1 equivalent of menaquinone. The structure shows that TM0 forms part of a cleft to accommodate the menaquinol-7 substrate. Crystals which have been soaked with the quinol-analog inhibitor HQNO (N-oxo-2-heptyl-4-hydroxyquinoline) or 3-iodo-HQNO reveal a single binding site where the inhibitor forms hydrogen bonds to amino acid residues shown previously by spectroscopic methods to interact with the semiquinone state of menaquinone, a catalytic intermediate.


Assuntos
Bacillus subtilis/metabolismo , Cobre/química , Complexo IV da Cadeia de Transporte de Elétrons/química , Heme/química , Hidroquinonas/química , Sequência de Aminoácidos , Sítios de Ligação , Cristalografia por Raios X , Grupo dos Citocromos b/química , Transporte de Elétrons , Ligação de Hidrogênio , Modelos Moleculares , Naftóis/metabolismo , Oxirredutases , Conformação Proteica , Subunidades Proteicas/química , Bombas de Próton/química , Bombas de Próton/metabolismo , Terpenos/metabolismo , Vitamina K 2/análogos & derivados , Vitamina K 2/química
6.
ChemSusChem ; 13(3): 564-573, 2020 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-31808287

RESUMO

Electrofermentation actively regulates the bacterial redox state, which is essential for bioconversion and has been highlighted as an effective method for further improvements of the productivity of either reduced or oxidized platform chemicals. 1,3-Propanediol (1,3-PDO) is an industrial value-added chemical that can be produced from glycerol fermentation. The bioconversion of 1,3-PDO from glycerol requires additional reducing energy under anoxic conditions. The cathode-based conversion of glycerol to 1,3-PDO with various electron shuttles (2-hydroxy-1,4-naphthoquinone, neutral red, and hydroquinone) using Klebsiella pneumoniae L17 was investigated. The externally poised potential of -0.9 V vs. Ag/AgCl to the cathode increased 1,3-PDO (35.5±3.1 mm) production if 100 µm neutral red was used compared with non-bioelectrochemical system fermentation (23.7±2.4 mm). Stoichiometric metabolic flux and transcriptional analysis indicated a shift in the carbon flux toward the glycerol reductive pathway. The homologous overexpression of glycerol dehydratase (DhaB) and 1,3-PDO oxidoreductase (DhaT) enzymes synergistically enhanced 1,3-PDO conversion (39.3±0.8 mm) under cathode-driven fermentation. Interestingly, a small current uptake (0.23 mmol of electrons) caused significant metabolic flux changes with a concomitant increase in 1,3-PDO production. This suggests that both an increase in 1,3-PDO production and regulation of the cellular metabolic pathway are feasible by electrode-driven control in cathodic electrofermentation.


Assuntos
Glicerol/química , Klebsiella pneumoniae/metabolismo , Propilenoglicóis/química , Técnicas Eletroquímicas/métodos , Eletrodos , Transporte de Elétrons , Fermentação , Hidroliases/metabolismo , Hidroquinonas/química , Naftoquinonas/química , Vermelho Neutro/química , Oxirredução , Oxirredutases/metabolismo , Transdução de Sinais
7.
Soft Matter ; 15(42): 8589-8602, 2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31642835

RESUMO

In this work, we synthesized electroactive and degradable microgels based on biomacromolecular building blocks, which enable the controlled release of therapeutic drugs. Functional chitosan-poly(hydroquinone) (Ch:PHQ) microgels exhibiting redox-active and pH-sensitive properties were synthesized by an oxidative polymerization in an inverse miniemulsion system. Physically crosslinked microgels were formed by polymerization of hydroquinone in the presence of chitosan through the formation of hydrogen bonds between PHQ and Ch. A series of microgel samples with variable Ch : PHQ ratios were synthesized. These obtained microgels exhibit pH-responsive properties due to the protonation/deprotonation of amino-groups of chitosan in the microgel system. Poly(hydroquinone) is a redox-active polymer exhibiting a two-electron/proton-transfer behavior and conveys this property to the microgels as confirmed by cyclic voltammetry. In addition, the microgels can be switched by electrochemical means: they swell in the oxidized state or shrink in the reduced state. In the presence of urea or lysozyme, the microgels undergo a fast degradation due to the disruption of hydrogen bonds acting as physical crosslinks in the microgel networks or due to the cleavage of glucosidic linkages of the incorporated chitosan scaffold, respectively. Doxorubicin (DOX), an anticancer drug, could be effectively encapsulated into the microgels and released in the presence of an enzyme, indicating that these biodegradable microgels could be used as drug delivery vehicles for tumor cells.


Assuntos
Quitosana/química , Hidroquinonas/química , Microgéis/química , Polímeros/química , Animais , Antibióticos Antineoplásicos/química , Antibióticos Antineoplásicos/farmacologia , Doxorrubicina/química , Doxorrubicina/farmacologia , Portadores de Fármacos/química , Técnicas Eletroquímicas , Fibroblastos/citologia , Ligação de Hidrogênio , Camundongos , Muramidase/química , Ureia/química
8.
Chem Commun (Camb) ; 55(83): 12559-12562, 2019 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-31577294

RESUMO

A fluorescent dye, 2,3-dicyanohydroquinone (DCH), was optimized for use as a new matrix for positive-ion MALDI-MS imaging, and it provided enhanced lipid detection and imaging in biological tissues. The properties of DCH, include a strong ultraviolet absorption, low volatility in a high-vacuum (∼10-7 mbar) source, super chemical stability, µm-sized matrix crystals, uniform matrix deposition, and high ionization efficiency for the detection of lipids.


Assuntos
Encéfalo/diagnóstico por imagem , Corantes Fluorescentes/química , Hidroquinonas/química , Lipídeos/análise , Fígado/química , Sementes/química , Animais , Brassicaceae/química , Camundongos , Ratos , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz
9.
Analyst ; 144(19): 5794-5801, 2019 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-31464300

RESUMO

We report here a highly sensitive sandwich type electrochemical aptasensor for lysozyme (lys) detection by the integration of an antifouling interface with HRP-based signal amplification. The biosensing interface with antifouling ability is designed, consisting of a lys-binding aptamer (LBA), dithiothreitol (DTT) and mercaptohexanol (MCH). When lys is captured by the immobilized LBA due to the specific recognition of the aptamer, gold nanoparticles (AuNPs) functionalized with HRP and LBA (HRP-AuNP-LBA) are further conjugated to the surface-bound lys, forming a sandwich assay format. HRP catalyzes the chemical oxidation of hydroquinone (HQ) by hydrogen peroxide (H2O2) to produce benzoquinone (BQ) which results in a large electrochemical reduction signal of BQ. Therefore, this reduction signal measured by differential pulse voltammetry (DPV) is used to detect lys. The catalytic behavior of HRP toward the reaction between HQ and H2O2, together with the high loading of HRP on AuNPs, remarkably amplifies the signal. A linear relationship between the DPV response and the logarithm of lys concentration from 0.01 pg mL-1 to 105 pg mL-1 with a detection limit of 0.003 pg mL-1 (S/N = 3) is obtained. The proposed biosensing platform combines antifouling ability and signal amplification, resulting in high sensitivity, providing an effective way for ultrasensitive assay of protein biomarkers in complex media.


Assuntos
Aptâmeros de Nucleotídeos/química , Técnicas Biossensoriais/métodos , Técnicas Eletroquímicas/métodos , Peroxidase do Rábano Silvestre/química , Muramidase/sangue , Armoracia/enzimologia , Sequência de Bases , Ouro/química , Humanos , Peróxido de Hidrogênio/química , Hidroquinonas/química , Limite de Detecção , Nanopartículas Metálicas/química , Muramidase/química , Reprodutibilidade dos Testes
10.
Mar Drugs ; 17(9)2019 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-31450731

RESUMO

Encouraged by the promising antitumoral, antiangiogenic, and antilymphangiogenic properties of toluquinol, a set of analogues of this natural product of marine origin was synthesized to explore and evaluate the effects of structural modifications on their cytotoxic activity. We decided to investigate the effects of the substitution of the methyl group by other groups, the introduction of a second substituent, the relative position of the substituents, and the oxidation state. A set of analogues of 2-substituted, 2,3-disubstituted, and 2,6-disubstituted derived from hydroquinone were synthesized. The results revealed that the cytotoxic activity of this family of compounds could rely on the hydroquinone/benzoquinone part of the molecule, whereas the substituents might modulate the interaction of the molecule with their targets, changing either its activity or its selectivity. The methyl group is relevant for the cytotoxicity of toluquinol, since its replacement by other groups resulted in a significant loss of activity, and in general the introduction of a second substituent, preferentially in the para position with respect to the methyl group, was well tolerated. These findings provide guidance for the design of new toluquinol analogues with potentially better pharmacological properties.


Assuntos
Antineoplásicos/farmacologia , Desenho de Fármacos , Hidroquinonas/farmacologia , Antineoplásicos/síntese química , Linhagem Celular Tumoral , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Hidroquinonas/química , Estrutura Molecular , Relação Estrutura-Atividade
11.
Anal Chim Acta ; 1079: 94-102, 2019 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-31387724

RESUMO

A shrimp tropomyosin (TPM) immunosensor has been developed and optimized to detect trace amounts of shrimp (in the ppm range), based on a combination of an amperometric transduction, magnetic particles and disposable screen-printed electrodes. The approach is based on the implementation of a sandwich immunoassay format on the surface of magnetic beads and their coupling onto disposable screen-printed electrodes to finally register the amperometric response at -200 mV vs. Ag pseudo-reference electrode, using H2O2 as enzymatic substrate and hydroquinone as redox mediator. The use of carboxyl-functionalized magnetic microbeads (MBs) and in-house made magnetic nanoparticles (MNPs) as solid supports have been evaluated and compared. Our experimental results confirm that the use of MBs, in addition to simplifying the test protocol, improves the resulting sensitivity, so they were selected for the implementation of the immunosensor. In the optimized experimental conditions, the developed immunosensor offered a LOD of 47 pg mL-1 for amperometric determination of shrimp TPM standards and great selectivity against TPM from other sources, thus allowing differentiation between crustaceans (shrimp) and mollusks (squid). Applicability studies demonstrated successful determination both in crude and cooked samples using very simple protocols. Additionally, processed foods based on fish and mollusks that could potentially include crustaceans in their composition have been analyzed using the sensor and compared to the declared ingredients. The sensitivity and specificity showed by the sensor in the analysis of heterogeneous food samples without a previous purification or enrichment stage, also outperforms existing solutions in terms of time and cost effectiveness and permits its direct and smooth implementation in the food industry for routine allergen analyses.


Assuntos
Alérgenos/análise , Contaminação de Alimentos/análise , Tropomiosina/análise , Alérgenos/imunologia , Animais , Anticorpos/imunologia , Armoracia/enzimologia , Técnicas Eletroquímicas/métodos , Análise de Alimentos/métodos , Peroxidase do Rábano Silvestre/química , Peróxido de Hidrogênio/química , Hidroquinonas/química , Imunoensaio/métodos , Limite de Detecção , Penaeidae/química , Tropomiosina/imunologia
12.
J Antibiot (Tokyo) ; 72(11): 793-799, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31341274

RESUMO

New hydroquinone derivatives bearing a vinyl alkyne, pestalotioquinols A and B, were isolated from a fungal culture broth of Pestalotiopsis microspora. The structures of these novel compounds were determined by interpretation of spectroscopic data (1D/2D NMR, MS, and IR), and the absolute configuration of the stereogenic center of pestalotioquinol A was assigned using the modified Mosher's method. Nerve growth factor-differentiated neuronal PC12 cells were pretreated with pestalotioquinols A and B and removed from the medium, and then treated with a generator of peroxynitrite (ONOO-), a reactive nitrogen species, to induce cell death. The cytotoxicity of the treated cells was assessed by measuring lactate dehydrogenase leakage. As a result, 1-3 µM pretreatment of pestalotioquinols A and B rescued neuronal PC12 cells from peroxynitrite-induced cytotoxicity and the protective activity was sustained after removing each compound from the medium. These results demonstrate that pestalotioquinol derivatives are a new class of hydroquinones possessing a vinyl alkyne and exhibiting relatively high neuroprotective effects.


Assuntos
Ascomicetos/metabolismo , Hidroquinonas/química , Hidroquinonas/farmacologia , Animais , Sobrevivência Celular/efeitos dos fármacos , Estrutura Molecular , Neurônios/efeitos dos fármacos , Células PC12 , Ratos
13.
Molecules ; 24(13)2019 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-31277409

RESUMO

We report the development of a new colorimetric probe (L-ol) for investigations of the redox process regulated by hypochlorous acid (HOCl) and glutathione (GSH). The HOCl/GSH redox-switching cycle process was investigated in detail by UV-vis absorption spectroscopy, colorimetric analysis assay and high-resolution mass spectrometry (HRMS). The switchable absorbance responses were attributed to the HOCl-induced oxidation of the p-methoxyphenol unit to the benzoquinone derivative (L-one) and sequential reduction of L-one to hydroquinone (L-ol') by GSH. In phosphate-buffered saline (PBS) buffer, the absorbance of L-ol at 619 nm underwent a remarkable bathochromic-shift, accompanied by a color change from pale yellow to blue in the presence of HOCl. With further addition of GSH, the absorbance of L-one exclusively recovered to the original level. Meanwhile, the blue-colored solution returned to the naive pale yellow color in the presence of GSH. The detection limits for HOCl and GSH were calculated to be 6.3 and 96 nM according to the IUPAC criteria. Furthermore, L-ol-loaded chromatography plates have been prepared and successfully applied to visualize and quantitatively analyze HOCl in several natural waters.


Assuntos
Colorimetria/métodos , Glutationa/análise , Ácido Hipocloroso/análise , Benzoquinonas/química , Cor , Hidroquinonas/química , Sondas Moleculares/síntese química , Sondas Moleculares/química , Oxirredução , Espectrofotometria Ultravioleta , Fatores de Tempo , Água/química
14.
Mar Drugs ; 17(7)2019 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-31331110

RESUMO

Several known sesquiterpenoid quinones and quinols (1-9), and kauamide (10), a new polyketide-peptide containing an 11-membered heterocycle, were isolated from the extracts of the Hawaiian marine sponge Dactylospongia elegans. The planar structure of 10 was determined from spectroscopic analyses, and its relative and absolute configurations were established from density functional theory (DFT) calculations of the GIAO NMR shielding tensors, and advanced Marfey's analysis of the N-MeLeu residue, respectively. Compounds 1 and 3 showed moderate inhibition of ß-secretase 1 (BACE1), whereas 1-9 exhibited moderate to potent inhibition of growth of human glioma (U251) cells. Compounds 1-2 and 4-7 were also active against human pancreatic carcinoma (Panc-1) cells.


Assuntos
Antineoplásicos/farmacologia , Inibidores Enzimáticos/farmacologia , Poríferos/química , Sesquiterpenos/farmacologia , Secretases da Proteína Precursora do Amiloide/antagonistas & inibidores , Animais , Antineoplásicos/química , Antineoplásicos/isolamento & purificação , Ácido Aspártico Endopeptidases/antagonistas & inibidores , Linhagem Celular Tumoral , Ensaios de Seleção de Medicamentos Antitumorais , Inibidores Enzimáticos/química , Inibidores Enzimáticos/isolamento & purificação , Glioma/tratamento farmacológico , Glioma/patologia , Hawaii , Compostos Heterocíclicos/química , Compostos Heterocíclicos/isolamento & purificação , Compostos Heterocíclicos/farmacologia , Humanos , Hidroquinonas/química , Hidroquinonas/isolamento & purificação , Hidroquinonas/farmacologia , Estrutura Molecular , Neoplasias Pancreáticas/tratamento farmacológico , Neoplasias Pancreáticas/patologia , Quinonas/química , Quinonas/isolamento & purificação , Quinonas/farmacologia , Sesquiterpenos/química , Sesquiterpenos/isolamento & purificação
15.
J Food Sci ; 84(8): 2042-2049, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31313292

RESUMO

It is important to inhibit the food-derived, potentially hazardous chemical glycated lipids by natural products. A model system was established and the products are identified to study the inhibitory mechanism of four types of catechin, resveratrol (RES), and the synthetic antioxidants butylated hydroxylanisole (BHA) and tert-butylhydroquinone (TBHQ) on the formation of carboxymethyl 1,2-dipalmitoyl-sn-glycero-3-phosphatidylethanolamine (CM-DPPE) by determining hydroxyl radical (OH·), Amadori-1,2-dipalmitoyl-sn-glycero-3-phosphatidylethanolamine (Amadori-DPPE) and glyoxal (GO). The results show that the inhibitory rates of catechin and RES on the content of CM-DPPE in the model system are higher than those of BHA and TBHQ. There are at least two inhibitory mechanisms of antioxidants on CM-DPPE. (1) Antioxidants scavenge OH·, which blocks the process of Amadori-DPPE oxidation to form CM-DPPE. (2) Antioxidants trap GO, which blocks the reaction between GO and DPPE to form CM-DPPE. This research will reveal the inhibitory mechanisms of natural antioxidants on glycated lipids from the aspect of scavenging OH· and trapping GO. PRACTICAL APPLICATION: Food manufacturers should pay attention on the production of glycated lipids in food processing. This study will provide the theoretical basis for the use of natural products to inhibit the formation of food-derived glycated lipids. Natural products, such as catechin and resveratrol, can substitute chemical synthesis antioxidants, such as butylated hydroxylanisole and tert-butylhydroquinone, in food processing, which inhibit the formation of glycated lipids.


Assuntos
Hidroxianisol Butilado/química , Catequina/química , Hidroquinonas/química , Fosfatidiletanolaminas/química , Resveratrol/química , Antioxidantes/química , Oxirredução , Fosfatidiletanolaminas/antagonistas & inibidores
16.
Appl Biochem Biotechnol ; 189(4): 1291-1303, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31254228

RESUMO

With growing concern about the possible risks and side effects of antibiotic drugs, more and more natural products with antibacterial activity are studied as the substitutes. In this paper, the antibacterial activity of hydroquinone and arbutin in Ainsliaea bonatii was investigated, which both displayed relatively strong antibacterial activity against Staphylococcus aureus (SA), methicillin-resistant S. aureus (MRSA), and extended spectrum ß-lactamase S. aureus (ESBL-SA). The antibacterial mechanism of hydroquinone had been explored by scanning electron microscopy (SEM), alkaline phosphatase (AKP), and bacterial extracellular protein leakage. Results showed that hydroquinone could destroy the bacterial cell wall and membrane, increase permeability, lead leakage of intracellular substance affect synthesis of protein, and influence expression of genes.


Assuntos
Antibacterianos/farmacologia , Arbutina/farmacologia , Hidroquinonas/farmacologia , Lamiaceae/química , Staphylococcus aureus Resistente à Meticilina/metabolismo , Antibacterianos/química , Arbutina/química , Hidroquinonas/química , Staphylococcus aureus Resistente à Meticilina/ultraestrutura
17.
Anal Chim Acta ; 1074: 80-88, 2019 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-31159942

RESUMO

A rapid and sensitive electrochemical biosensor was constructed to detect Salmonella using invA gene biosensor. The biosensing was based on polyrrole-reduced graphene oxide (PPy-rGO) nanocomposite modified glassy carbon electrode (GCE) and signal amplification with horseradish peroxidase-streptavidin biofunctionalized gold nanoparticles (AuNPs-HRP-SA). PPy-rGO was prepared at 60 °C by chemical reduction of PPy-functionalized graphene oxide (PPy-GO) that was synthesized by in situ polymerization at room temperature. The detection signal was amplified via enzymatic reduction of H2O2 in the presence of hydroquinone (HQ) using AuNPs-HRP-SA as nanotag. Under optimal conditions, the differential pulse voltametric (DPV) signal from the biosensor was linearly related to the logarithm of target invA gene concentrations from 1.0 × 10-16 to 1.0 × 10-10 M, and the limit of detection (LOD) was 4.7 × 10-17 M. The biosensor can also detect Salmonella in the range of 9.6 to 9.6 × 104 CFU mL-1, with LOD of 8.07 CFU mL-1. The biosensor showed good regeneration ability, acceptable selectivity, repeatability and stability, which bode well as an alternative method for Salmonella screening.


Assuntos
Proteínas de Bactérias/genética , Técnicas de Tipagem Bacteriana/métodos , Grafite/química , Nanopartículas Metálicas/química , Polímeros/química , Pirróis/química , Salmonella/isolamento & purificação , Técnicas Biossensoriais/métodos , Carbono , DNA Bacteriano/genética , Técnicas Eletroquímicas/instrumentação , Técnicas Eletroquímicas/métodos , Eletrodos , Enzimas Imobilizadas/química , Ouro/química , Peroxidase do Rábano Silvestre/química , Peróxido de Hidrogênio/química , Hidroquinonas/química , Limite de Detecção , Nanocompostos/química , Hibridização de Ácido Nucleico , Oxirredução , Salmonella/genética , Estreptavidina/química
18.
Med Hypotheses ; 128: 69-75, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31203913

RESUMO

Vitiligo (VL) is a chronic autoimmune pigmentation disorder characterized by destruction of melanocytes. The condition is associated with several other autoimmune diseases, but autoimmune thyroid diseases, especially Hashimoto's thyroiditis (HT), is the most prevalent organ-specific autoimmune disease with a co-morbidity up to 34%. Among the many hypotheses that have been proposed for the pathogenesis of both diseases, autoimmunity and oxidative stress-mediated toxicity in melanocytes or thyrocytes, respectively, have been the most widely accepted - with autoimmunity being the presumed consequence of oxidative stress-mediated toxicity. However, the predominant etiologic basis for impairment of redox balance has rarely been studied. The two autoimmune diseases are not only linked by a concordance of clinical presentations and an autoimmune/oxidative stress-mediated toxicity pathogenesis but also by an apparent biochemical commonality. The target molecules produced in the thyroid and skin, i.e., thyroxine and melanin, respectively, are derived from the same primordial parent molecule, tyrosine. On the basis of these similarities between Hashimoto's thyroiditis and vitiligo, specifically with respect to the activation of oxidative stress, we propose a novel hypothesis accounting for the destruction of melanocytes or thyrocytes in VL and AT. We suggest a new therapeutic regimen of quinone derivatives to combat ROS-induced autoimmunity resulting from this common biochemical etiologic error.


Assuntos
Doenças Autoimunes/fisiopatologia , Doença de Hashimoto/fisiopatologia , Estresse Oxidativo , Vitiligo/fisiopatologia , Animais , Doenças Autoimunes/complicações , Autoimunidade , Benzoquinonas/química , Modelos Animais de Doenças , Doença de Hashimoto/complicações , Humanos , Peróxido de Hidrogênio/química , Hidroquinonas/química , Melaninas/química , Melanócitos/citologia , Melanócitos/metabolismo , Modelos Teóricos , Oxidantes/química , Oxirredução , Oxigênio/química , Espécies Reativas de Oxigênio/metabolismo , Superóxidos/química , Células Epiteliais da Tireoide/metabolismo , Glândula Tireoide/metabolismo , Tiroxina , Vitiligo/complicações
19.
Int J Mol Sci ; 20(10)2019 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-31137618

RESUMO

The effective delivery of menahydroquinone-4 (MKH), an active form of menaquinone-4 (MK-4, vitamin K2(20)), to the skin is beneficial in the treatment of various skin pathologies. However, its delivery through the application of MK-4 to the skin is hampered due to the photoinstability and phototoxicity of MK-4. This study aimed to evaluate the potential of ester prodrugs of MKH for its delivery into the skin to avoid the abovementioned issues. The ester prodrugs, MKH 1,4-bis-N,N-dimethylglycinate hydrochloride (MKH-DMG) and MKH 1,4-bis-hemisuccinate (MKH-SUC), were prepared using our previously reported methods. Photostability was determined under artificial sunlight and multi-wavelength light irradiation, phototoxicity was determined by intracellular ROS formation and cell viability of UVA-irradiated human epidermal keratinocyte cells (HaCaT), and delivery of MKH into HaCaT cells was assessed by measuring menaquinone-4 epoxide (MKO) levels. MKH prodrugs showed higher photostability than MK-4. Although MK-4 induced cellular ROS and reduced cell viability after UVA irradiation, MKH prodrugs did not affect either ROS generation or cell viability. MKH prodrugs enhanced intracellular MKO, indicating effective delivery of MKH and subsequent carboxylation activity. In conclusion, these MKH prodrugs show potential for the delivery of MKH into the skin without photoinstability and phototoxicity.


Assuntos
Hidroquinonas/toxicidade , Queratinócitos/efeitos dos fármacos , Pró-Fármacos/toxicidade , Vitamina K 2/análogos & derivados , Linhagem Celular , Humanos , Hidroquinonas/química , Queratinócitos/metabolismo , Pró-Fármacos/química , Espécies Reativas de Oxigênio/metabolismo , Vitamina K 2/química , Vitamina K 2/toxicidade
20.
Mikrochim Acta ; 186(6): 374, 2019 05 23.
Artigo em Inglês | MEDLINE | ID: mdl-31123904

RESUMO

An ultrasensitive voltammetric aptasensor was constructed to analyze cardiac troponin I (cTnI). It is based on DNA nanotetrahedron (NTH) linked dual-aptamer (dAPT) and magnetic metal organic frameworks (mMOFs) of type Fe3O4@UiO-66. Firstly, the DNA NTH linked dAPT (Tro4 and Tro6) were immobilized on a gold electrode for improving the capture efficiency of cTnI. The novel mMOFs Fe3O4@UiO-66 was then decorated by Au@Pt nanoparticles (Au@PtNPs), horseradish peroxidase (HRP), G-quadruplex/hemin (GQH) DNAzyme, and two types of aptamers to form signaling nanoprobes. In the presence of cTnI, an aptamer-protein-nanoprobe sandwich-type structure is formed. Afterward, the nanoprobes including enzyme, GQH DNAzyme and Fe3O4@UiO-66/Au@PtNP were utilized to catalyze the oxidation of hydroquinone by hydrogen peroxide for the electrochemical signals amplification, typically at a working potential of -0.1 V (vs. Ag/AgCl). The voltammetric signal increases linearly in the 0.01 to 100 ng·mL-1 cTnI concentration range, and the detection limit is 5.7 pg·mL-1. Graphical abstract An ultrasensitive voltammetric aptasensor was constructed to analyze cardiac troponin I (cTnI) based on DNA nanotetrahedron linked dual-aptamer and magnetic metal organic frameworks of type Fe3O4@UiO-66. The results indicated the aptasensor has a wide linear response range (0.01 to 100 ng/mL) and low detection limit (5.74 pg/mL) for cTnI. GE: gold electrode; MCH: 6-Mmercapto-1-hexanol; HRP: horseradish peroxidase; HQ: hydroquinone; BQ: benzoquinone.


Assuntos
Aptâmeros de Nucleotídeos/química , Técnicas Biossensoriais/métodos , DNA Catalítico/química , Técnicas Eletroquímicas/métodos , Estruturas Metalorgânicas/química , Troponina I/sangue , Armoracia/enzimologia , Sequência de Bases , DNA Catalítico/genética , Quadruplex G , Ouro/química , Hemina/química , Peroxidase do Rábano Silvestre/química , Humanos , Peróxido de Hidrogênio/química , Hidroquinonas/química , Limite de Detecção , Nanopartículas de Magnetita/química , Oxirredução , Reprodutibilidade dos Testes , Prata/química
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