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1.
Biosensors (Basel) ; 12(9)2022 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-36140091

RESUMO

Blood iron levels play a vital role in oxygen metabolism and energy generation whilst transporter protein, transferrin, binds and delivers iron to the transferrin receptor of endosomal compartments of cells. Consequently, the iron-binding capacity of transferrin is an important indicator for many diseases, and its measurements are used in the diagnosis and treatment of anaemias. Various assays, including Total Iron Binding Capacity (TIBC), Unsaturated Iron-Binding Capacity (UIBC) and Transferrin Saturation (TS), were developed to assess the iron-binding capacity of transferrin. Clinically, UIBC is measured in serum by a multi-step liquid ferrozine method and subjected to interference from conditions such as haemolysis and lipemia. Here, we report a quick method that directly measures the concentration of apotransferrin in EDTA-treated plasma, theoretically equivalent to UIBC. Importantly, this supramolecular assembly-based method is more time-efficient, cost-effective and insensitive to serum cation fluctuations. With additional colorimetric property, this method also provides a visual indicator for abnormal health conditions with extreme transferrin statuses such as those found in cancers. Its minimal requirement for equipment would be particularly useful for diagnosis in remote and under-developed regions.


Assuntos
Ferro , Receptores da Transferrina , Ácido Edético , Ferrozina , Oxigênio
2.
Inorg Chem ; 61(34): 13543-13553, 2022 Aug 29.
Artigo em Inglês | MEDLINE | ID: mdl-35960895

RESUMO

PM0042 protein from the Gram-negative bacterial pathogen Pasteurella multocida is homologous to the heme-degrading enzyme HutZ belonging to the pyridoxine-5-phosphate oxidase-like family. A characteristic feature of PM0042 is possession of a glycine-histidine (GH) repeat sequence at the C-terminal region. In this study, we examined the heme degradation ability of PM0042, with a particular focus on the role of the GH repeat sequence. PM0042 was expressed in Escherichia coli and successfully purified using a nickel (Ni2+)-affinity column without a histidine tag, suggesting that its GH motif facilitates binding to Ni2+. Reaction with ascorbic acid induced a significant decrease in the Soret band, suggesting the breakage of heme. While a Fe2+-ferrozine complex was not formed upon addition of ferrozine to the solution after the reaction, prior addition of metal ions to fill the metal binding site in the GH repeat sequence led to increased complex formation. In the presence of Fe2+, the heme degradation rate was accelerated ∼threefold, supporting the theory that Fe2+ binds the PM0042 protein (possibly at the GH repeat sequence) and enhances its heme degradation activity. In contrast to HutZ from Vibrio cholerae in which enzymatic activity is regulated by the protonation status of the heme proximal ligand, heme reduction is not the rate-determining step for PM0042. Rather, proton transfer to reduced oxyheme is affected, as established with the H2O/D2O isotope experiment. Based on the collective findings, the GH repeat sequence of PM0042 is proposed to function as a metal sensor that modulates iron uptake via the heme-degrading process in P. multocida.


Assuntos
Histidina , Pasteurella multocida , Proteínas de Bactérias , Ferrozina , Glicina , Heme
3.
Environ Sci Technol ; 56(12): 9123-9132, 2022 06 21.
Artigo em Inglês | MEDLINE | ID: mdl-35675652

RESUMO

Fe(II) has been extensively studied due to its importance as a reductant in biogeochemical processes and contaminant attenuation. Previous studies have shown that ligands can alter aqueous Fe(II) redox reactivity but their data interpretation is constrained by the use of probe compounds. Here, we employed mediated electrochemical oxidation (MEO) as an approach to directly quantify the extent of Fe(II) oxidation in the absence and presence of three model organic ligands (citrate, nitrilotriacetic acid, and ferrozine) across a range of potentials (EH) and pH, thereby manipulating oxidation over a broad range of fixed thermodynamic conditions. Fe(III)-stabilizing ligands enhanced Fe(II) reactivity in thermodynamically unfavorable regions (i.e., low pH and EH) while an Fe(II) stabilizing ligand (ferrozine) prevented oxidation across all thermodynamic regions. We experimentally derived apparent standard redox potentials, EHϕ, for these and other (oxalate, oxalate2, NTA2, EDTA, and OH2) Fe-ligand redox couples via oxidative current integration. Preferential stabilization of Fe(III) over Fe(II) decreased EHϕ values, and a Nernstian correlation between EHϕ and log(KFe(III)/KFe(II)) exists across a wide range of potentials and stability constants. We used this correlation to estimate log(KFe(III)/KFe(II)) for a natural organic matter isolate, demonstrating that MEO can be used to measure iron stability constant ratios for unknown ligands.


Assuntos
Compostos Férricos , Compostos Ferrosos , Compostos Ferrosos/química , Ferrozina , Ligantes , Oxalatos , Oxirredução
4.
Chem Biodivers ; 19(8): e202200461, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35773202

RESUMO

Secondary plant metabolites are chemical compounds produced by plants through a variety of metabolic pathways. It is known that these compounds, among others, monoterpenes, are characterized by holding valuable pro-health activities when consumed or applied. Taking into account the development of civilizational diseases, eating foods enriched with compounds such as the monoterpenes is highly recommended. Good sources of such health-promoting food items include common fruits and vegetables, seed sources and plant parts used to enhance flavour such as spices. It is known that monoterpene compounds instigate or contribute to a variety of biological activities. It is known that the compounds can scavenge free radicals, reduce Fe(III) and inhibit AChE which are considered as possible anti-neurodegenerative activities. The aim of the presented study was to determinate another activity of selected monoterpenes, namely towards reducing and chelating Cu(II) and Fe(II), respectively. The assays were based on colorimetric CUPRAC and ferrozine-based methods. Study results explicitly indicated chelation and reduction activities of the selected monoterpenes. These properties considerably support the benefits of consuming plants rich in these compounds.


Assuntos
Cobre , Monoterpenos , Cobre/química , Ferrozina , Íons , Ferro , Monoterpenos/química
5.
J Inorg Biochem ; 220: 111460, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-33866045

RESUMO

Iron is an essential nutrient for virtually all forms of life. Because of its redox properties and involvement in a wide range of biological processes, a number of qualitative and quantitative chemical tools have been developed to detect reduced (Fe2+) and oxidized (Fe3+) forms of iron in biomolecules. These types of measurements are not only important in detecting iron species in solution, but also in understanding iron distribution, accumulation, and role in physiological and pathological processes. Here, we use UV-vis spectrophotometry and three common chromogenic reagents, ferrozine, 2,2'-bipyridine, and 1,10-phenanthroline to detect and quantify the concentration of ferrous ions in aqueous solutions, owing to the unique absorption spectra, specific molar absorptivity, and characteristic colors of these Fe2+-chelator complexes. Our results show that the kinetics of the formation of the {Fe2+-(ferrozine)3} complex, but not the{Fe2+-(bipyridine)3} or the {Fe(II)-(phenanthroline)3} complexes depend on the concentration of the iron chelator, requiring up to 20 min to complete when close to stoichiometric ratios are employed. The molar absorptivity values of these complexes under excess chelator concentrations were ~ 10% to 15% higher than reported literature values (i.e. 31,500 ± 1500 M-1 cm-1 for ferrozine at 562 nm, 9950 ± 100 M-1 cm-1 for 2,2'-bipyridine at 522 nm, and 12,450 ± 370 M-1 cm-1 for 1,10-phenanthroline at 510 nm). Our results have important implications when quantifying iron in biological systems and reveal optimal experimental conditions that must be employed for the accurate measurements of ferrous ions, whether free in solution, or after reduction of protein-bound ferric ions.


Assuntos
2,2'-Dipiridil/química , Quelantes/química , Complexos de Coordenação/química , Ferrozina/química , Ferro/química , Fenantrolinas/química , Concentração de Íons de Hidrogênio , Cinética , Ligantes
6.
Biosci Biotechnol Biochem ; 84(10): 1967-1974, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32619142

RESUMO

This work presents the development and validation of a simple, rapid, and cost-effective spectrophotometric method for quantitative analysis of uric acid in biological samples. The method relies upon uric acid-led reduction of Fe(III) to Fe(II) of sample/standard solutions which stoichiometrically engages ferrozine to form a magenta-colored complex. Different parameters including pH, metal and chelator concentrations, temperature, etc., were optimized for the maximum intensity and stability of the complex. The uric acid concentrations of synthetic/plasma solutions were determined by comparing the color intensity of Fe(ferrozine)3 2+ complex produced by test solution with the standard curve formed by known uric acid concentrations. The method was validated in accordance with ICH guidelines and subjected to human plasma analysis. The results obtained were compared with a reference (enzymatic) method which revealed that there was no significant difference between the two methods at 95% confidence level. The method is highly specific, precise, linear, accurate, and robust.


Assuntos
Análise Química do Sangue/métodos , Colorimetria/métodos , Ferrozina/química , Ferro/química , Ácido Úrico/sangue , Análise Química do Sangue/economia , Análise Química do Sangue/normas , Cor , Colorimetria/economia , Colorimetria/normas , Análise Custo-Benefício , Humanos , Concentração de Íons de Hidrogênio , Padrões de Referência , Temperatura , Fatores de Tempo
7.
Molecules ; 24(17)2019 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-31443451

RESUMO

An efficient microwave-assisted extraction (MAE) combined with in-capillary [Fe(ferrozine)3]2+-capillary electrophoresis-Diode Array Detector (in-capillary [Fe(ferrozine)3]2+-CE-DAD) was developed to screen active components with the ability to chelate ferrous ions and determine the total antioxidant activity. The MAE conditions, including methanol concentration, extraction power, extraction time, and the ratio of material to liquid, were optimized by an L9(34) orthogonal experiment. Background buffer, voltage, and cartridge temperature that affect the separation of six compounds were optimized. It was found that rutin and quercetin were the main components chelating ferrous ions in Flos Sophorae Immaturus (Flos Sophorae) by the in-capillary [Fe(ferrozine)3]2+-CE-DAD. The recoveries were ranged from 95.2% to 104%. It was concluded that the MAE combined with in-capillary [Fe(ferrozine)3]2+-CE-DAD method was a simple, reliable, and efficient tool for screening active components from the complex traditional Chinese medicine samples and evaluating their ability to chelate ferrous ions.


Assuntos
Fracionamento Químico , Medicamentos de Ervas Chinesas/química , Medicamentos de Ervas Chinesas/farmacologia , Eletroforese Capilar , Ferrozina/química , Ferrozina/farmacologia , Micro-Ondas , Análise de Variância , Antioxidantes/química , Antioxidantes/farmacologia , Fracionamento Químico/métodos , Cromatografia Líquida de Alta Pressão , Concentração de Íons de Hidrogênio , Concentração Inibidora 50 , Limite de Detecção , Reprodutibilidade dos Testes
8.
Sci Rep ; 9(1): 11491, 2019 08 07.
Artigo em Inglês | MEDLINE | ID: mdl-31391524

RESUMO

Phytic acid (PA) is a natural-occurring antioxidant, which plays an important role in many biological processes. PA is recognized as a potent inhibitor of lipid peroxidation because of its high affinity to multivalent cations, and it can play a role in osteogenic processes. However, its powerful chelating capacity is controversial because it can lead to a severe reduction of mineral availability in the organism. For this reason, compounds with beneficial biological properties of PA, but a modular ion binding capacity, are of high interest. In this work, we report the synthesis and physicochemical characterization of two hydroxylic derivatives of PA, named glycerylphytates (GPhy), through a condensation reaction of PA with glycerol (G). Both derivatives present antioxidant properties, measured by ferrozine/FeCl2 method and chelating activity with calcium ions depending on the content of glyceryl groups incorporated. Besides, the hydroxylic modification not only modulates the ion binding affinity of derivatives but also improves their cytocompatibility in human bone marrow mesenchymal cells (MSCs). Furthermore, GPhy derivatives display osteogenic properties, confirmed by COL1A and ALPL expression depending on composition. These positive features convert GPhy compounds into potent alternatives for those skeletal diseases treatments where PA is tentatively applied.


Assuntos
Antioxidantes/farmacologia , Quelantes/farmacologia , Glicerol/farmacologia , Osteogênese/efeitos dos fármacos , Ácido Fítico/farmacologia , Fosfatase Alcalina/metabolismo , Animais , Antioxidantes/química , Cálcio/metabolismo , Cátions Bivalentes/metabolismo , Diferenciação Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Quelantes/química , Colágeno Tipo I/metabolismo , Compostos Ferrosos/metabolismo , Ferrozina/farmacologia , Glicerol/química , Humanos , Células-Tronco Mesenquimais/efeitos dos fármacos , Células-Tronco Mesenquimais/fisiologia , Camundongos , Ácido Fítico/análogos & derivados , Ácido Fítico/química , Cultura Primária de Células , Células RAW 264.7 , Testes de Toxicidade Subaguda
9.
J Agric Food Chem ; 67(2): 680-687, 2019 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-30561197

RESUMO

Wine oxidation is reported to be linked to the iron species present in the wine, but spectrophotometric speciation is plagued by unstable measurements due to alterations to the reduction potential of iron by complexing agents. Ferrozine raises the reduction potential of iron by complexing preferentially to iron(II), inducing the reduction of iron(III) during analysis; here, EDTA is added to chelate iron(III) and to stabilize the forms of iron. Bisulfite addition allows the use of ferrozine for red wine analysis by mitigating color interference. Measurements agree with values from a previous method for iron(II) and from FAAS for total iron. Spike recoveries were in the range of 103.5-110.1%. The method is linear for iron concentrations in the range of 0.10-6.00 mg L-1 and offers good precision (CV 0.4-10.1%) and low limits of detection (0.02 mg L-1) and quantification (0.06 mg L-1). The method demonstrated changes to iron speciation during the oxygenation of red wines.


Assuntos
Ácido Edético/química , Ferrozina/química , Análise de Alimentos/métodos , Espectrofotometria/métodos , Vinho/análise , Quelantes/química , Oxirredução
10.
Cell Death Dis ; 9(10): 1025, 2018 10 04.
Artigo em Inglês | MEDLINE | ID: mdl-30287840

RESUMO

Procaspase-3-activating compound 1 (PAC-1) induces procaspase-3 activation via zinc chelation. However, whether PAC-1 employs other mechanisms remains unknown. Here we systematically screened for potent PAC-1 targets using 29 enhanced green fluorescent protein-labeled reporter cell lines and identified hypoxia-inducible factor 1α (HIF1α) and RAD51 pathways as PAC-1 targets. These results were verified in HepG2 cells and two other cancer cell lines. Mechanistically, PAC-1 specifically blocked HIF1α hydroxylation and upregulated HIF1α target genes. In addition, DNA damage, G1/S cell cycle arrest, and the inhibition of DNA synthesis were induced following PAC-1 administration. Interestingly, by using ferrozine-iron sequestration and iron titration assays, we uncovered the iron sequestering capacity of PAC-1. Additionally, the expression levels of iron shortage-related genes were also increased in PAC-1-treated cells, and iron (II) supplementation reversed all of the observed cellular responses. Thus, our results indicate that PAC-1 induces HIF1α stabilization and DNA damage by sequestering ferrous iron.


Assuntos
Caspase 3/metabolismo , Dano ao DNA/efeitos dos fármacos , Ferrozina/farmacologia , Hidrazonas/farmacologia , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Hipóxia/tratamento farmacológico , Ferro/farmacologia , Piperazinas/farmacologia , Apoptose/efeitos dos fármacos , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Pontos de Checagem da Fase G1 do Ciclo Celular/efeitos dos fármacos , Células Hep G2 , Humanos , Hipóxia/metabolismo , Rad51 Recombinase/metabolismo , Regulação para Cima/efeitos dos fármacos , Zinco/metabolismo
11.
Mol Imaging Biol ; 20(1): 55-64, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-28631141

RESUMO

PURPOSE: The purposes of this study are to characterize magneto-endosymbiont (ME) labeling of mammalian cells and to discern the subcellular fate of these living contrast agents. MEs are novel magnetic resonance imaging (MRI) contrast agents that are being used for cell tracking studies. Understanding the fate of MEs in host cells is valuable for designing in vivo cell tracking experiments. PROCEDURES: The ME's surface epitopes, contrast-producing paramagnetic magnetosomal iron, and genome were studied using immunocytochemistry (ICC), Fe and MRI contrast measurements, and quantitative polymerase chain reaction (qPCR), respectively. These assays, coupled with other common assays, enabled validation of ME cell labeling and dissection of ME subcellular processing. RESULTS: The assays mentioned above provide qualitative and quantitative assessments of cell labeling, the subcellular localization and the fate of MEs. ICC results, with an ME-specific antibody, qualitatively shows homogenous labeling with MEs. The ferrozine assay shows that MEs have an average of 7 fg Fe/ME, ∼30 % of which contributes to MRI contrast and ME-labeled MDA-MB-231 (MDA-231) cells generally have 2.4 pg Fe/cell, implying ∼350 MEs/cell. Adjusting the concentration of Fe in the ME growth media reduces the concentration of non-MRI contrast-producing Fe. Results from the qPCR assay, which quantifies ME genomes in labeled cells, shows that processing of MEs begins within 24 h in MDA-231 cells. ICC results suggest this intracellular digestion of MEs occurs by the lysosomal degradation pathway. MEs coated with listeriolysin O (LLO) are able to escape the primary phagosome, but subsequently co-localize with LC3, an autophagy-associated molecule, and are processed for digestion. In embryos, where autophagy is transiently suppressed, MEs show an increased capacity for survival and even replication. Finally, transmission electron microscopy (TEM) of ME-labeled MDA-231 cells confirms that the magnetosomes (the MRI contrast-producing particles) remain intact and enable in vivo cell tracking. CONCLUSIONS: MEs are used to label mammalian cells for the purpose of cell tracking in vivo, with MRI. Various assays described herein (ICC, ferrozine, and qPCR) allow qualitative and quantitative assessments of labeling efficiency and provide a detailed understanding of subcellular processing of MEs. In some cell types, MEs are digested, but the MRI-producing particles remain. Coating with LLO allows MEs to escape the primary phagosome, enhances retention slightly, and confirms that MEs are ultimately processed by autophagy. Numerous intracellular bacteria and all endosymbiotically derived organelles have evolved molecular mechanisms to avoid intracellular clearance, and identification of the specific processes involved in ME clearance provides a framework on which to develop MEs with enhanced retention in mammalian cells.


Assuntos
Comunicação Celular , Rastreamento de Células , Nanopartículas de Magnetita/química , Coloração e Rotulagem , Simbiose , Animais , Autofagia , Linhagem Celular Tumoral , Meios de Contraste/química , Ferrozina/metabolismo , Humanos , Ferro/metabolismo , Nanopartículas de Magnetita/ultraestrutura , Camundongos Endogâmicos BALB C , Ratos , Reprodutibilidade dos Testes , Frações Subcelulares/metabolismo
12.
Bull Exp Biol Med ; 162(2): 228-230, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27905038

RESUMO

Iron-chelating activity of synthesized spirocyclic hydroxamic acids, their toxicity, and effects on mitochondrial function were studied using primary culture of cerebral cortical neurons from newborn rats. All tested compounds effectively chelated Fe(II) ions. Activity of spirocyclic hydroxamic acids more strictly depended on the structure their piperidine, but not imidazolidine fragment. All compounds were non-toxic for normal neuronal culture.


Assuntos
Ácidos Hidroxâmicos/farmacologia , Quelantes de Ferro/farmacologia , Ferro/metabolismo , Mitocôndrias Hepáticas/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Compostos de Espiro/farmacologia , Animais , Animais Recém-Nascidos , Animais não Endogâmicos , Cátions Bivalentes , Sobrevivência Celular/efeitos dos fármacos , Córtex Cerebral/citologia , Córtex Cerebral/efeitos dos fármacos , Córtex Cerebral/metabolismo , Ferrozina/química , Ácidos Hidroxâmicos/síntese química , Quelantes de Ferro/síntese química , Masculino , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Mitocôndrias Hepáticas/metabolismo , Dilatação Mitocondrial/efeitos dos fármacos , Neurônios/metabolismo , Cultura Primária de Células , Ratos , Compostos de Espiro/síntese química , Relação Estrutura-Atividade
13.
Antimicrob Agents Chemother ; 60(1): 288-95, 2016 01.
Artigo em Inglês | MEDLINE | ID: mdl-26503658

RESUMO

The reasons why aminoglycosides are bactericidal have not been not fully elucidated, and evidence indicates that the cidal effects are at least partly dependent on iron. We demonstrate that availability of iron markedly affects the susceptibility of the facultative intracellular bacterium Francisella tularensis strain SCHU S4 to the aminoglycoside gentamicin. Specifically, the intracellular depots of iron were inversely correlated to gentamicin susceptibility, whereas the extracellular iron concentrations were directly correlated to the susceptibility. Further proof of the intimate link between iron availability and antibiotic susceptibility were the findings that a ΔfslA mutant, which is defective for siderophore-dependent uptake of ferric iron, showed enhanced gentamicin susceptibility and that a ΔfeoB mutant, which is defective for uptake of ferrous iron, displayed complete growth arrest in the presence of gentamicin. Based on the aforementioned findings, it was hypothesized that gallium could potentiate the effect of gentamicin, since gallium is sequestered by iron uptake systems. The ferrozine assay demonstrated that the presence of gallium inhibited >70% of the iron uptake. Addition of gentamicin and/or gallium to infected bone marrow-derived macrophages showed that both 100 µM gallium and 10 µg/ml of gentamicin inhibited intracellular growth of SCHU S4 and that the combined treatment acted synergistically. Moreover, treatment of F. tularensis-infected mice with gentamicin and gallium showed an additive effect. Collectively, the data demonstrate that SCHU S4 is dependent on iron to minimize the effects of gentamicin and that gallium, by inhibiting the iron uptake, potentiates the bactericidal effect of gentamicin in vitro and in vivo.


Assuntos
Antibacterianos/farmacologia , Francisella tularensis/efeitos dos fármacos , Gálio/farmacologia , Gentamicinas/farmacologia , Ferro/metabolismo , Tularemia/tratamento farmacológico , Animais , Carga Bacteriana , Bioensaio , Sinergismo Farmacológico , Feminino , Ferrozina/química , Francisella tularensis/crescimento & desenvolvimento , Francisella tularensis/metabolismo , Transporte de Íons , Fígado/efeitos dos fármacos , Fígado/metabolismo , Fígado/microbiologia , Macrófagos/efeitos dos fármacos , Macrófagos/metabolismo , Macrófagos/microbiologia , Camundongos , Camundongos Endogâmicos C57BL , Cultura Primária de Células , Baço/efeitos dos fármacos , Baço/metabolismo , Baço/microbiologia , Tularemia/microbiologia , Tularemia/patologia
14.
Environ Sci Technol ; 49(17): 10373-9, 2015 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-26274915

RESUMO

The production of the hydroxyl radical (HO·) is important in environmental chemistry. This study reports a new source of HO· generated solely from hydrogen peroxide (H2O2) activated by hydroxylamine (HA). Electron paramagnetic resonance analysis and the oxidation of a HO· probe, benzoic acid, were used to confirm the production of HO·. The production of HO· increased with increasing concentrations of either HA or H2O2 as well as decreasing pH. The second-order rate constant for the reaction was (2.2 ± 0.2) × 10(-4) M(-1) s(-1). HO· was probably produced in two steps: the activation of H2O2 by protonated HA and then reaction between the H2O2 and the intermediate protonated aminoxyl radical generated in the first step. Such a two-step oxidation can possibly be ascribed to the ionizable hydroxyl moiety in the molecular structure of HA, as is suggested by comparing the reactivity of a series of HA derivatives in HO· production. The results shed light on a previously unknown source of HO· formation, which broadens the understanding of its role in environmental processes.


Assuntos
Peróxido de Hidrogênio/química , Radical Hidroxila/química , Hidroxilamina/química , Óxidos N-Cíclicos/química , Espectroscopia de Ressonância de Spin Eletrônica , Ferrozina/química , Concentração de Íons de Hidrogênio , Indicadores e Reagentes , Quelantes de Ferro/química , Marcadores de Spin , Elementos de Transição
15.
Cell Mol Biol Lett ; 20(4): 562-70, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26146126

RESUMO

The role of metal (especially) iron ions has been postulated to play a prominent role in protein glycation, suggesting antiglycating effectiveness of metal chelators. However, this rule may not apply to all model glycation systems. We found that metal chelators are not effective in prevention of glycation of bovine serum albumin (BSA) in vitro, and there is no correlation between the antiglycating effects of 32 compounds and their iron chelation activity as measured with the ferrozine test. These data indicate that the glycation of BSA in vitro is iron-independent and is not a proper system to study the role of metals in protein glycation.


Assuntos
Quelantes/química , Produtos Finais de Glicação Avançada , Soroalbumina Bovina/química , Catalase/química , Quelantes/farmacologia , Ferrozina/química , Ferrozina/metabolismo , Glioxal/química , Glioxal/metabolismo , Técnicas In Vitro , Concentração Inibidora 50 , Ferro/química , Aldeído Pirúvico/química , Aldeído Pirúvico/metabolismo , Resinas Sintéticas/química , Soroalbumina Bovina/metabolismo , Superóxido Dismutase/química
16.
Antimicrob Agents Chemother ; 59(4): 2256-64, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25645825

RESUMO

Efficient iron acquisition is crucial for the pathogenesis of Mycobacterium tuberculosis. Mycobacterial iron uptake and metabolism are therefore attractive targets for antitubercular drug development. Resistance mutations against a novel pyrazolopyrimidinone compound (PZP) that is active against M. tuberculosis have been identified within the gene cluster encoding the ESX-3 type VII secretion system. ESX-3 is required for mycobacterial iron acquisition through the mycobactin siderophore pathway, which could indicate that PZP restricts mycobacterial growth by targeting ESX-3 and thus iron uptake. Surprisingly, we show that ESX-3 is not the cellular target of the compound. We demonstrate that PZP indeed targets iron metabolism; however, we found that instead of inhibiting uptake of iron, PZP acts as an iron chelator, and we present evidence that the compound restricts mycobacterial growth by chelating intrabacterial iron. Thus, we have unraveled the unexpected mechanism of a novel antimycobacterial compound.


Assuntos
Antibacterianos/farmacologia , Quelantes de Ferro/farmacologia , Mycobacterium smegmatis/efeitos dos fármacos , Pirazóis/farmacologia , Pirimidinonas/farmacologia , Farmacorresistência Bacteriana/efeitos dos fármacos , Farmacorresistência Bacteriana/genética , Ferrozina/metabolismo , Ferro/metabolismo , Testes de Sensibilidade Microbiana , Mycobacterium smegmatis/genética , Oxazóis/metabolismo , Pirazóis/síntese química , Pirimidinonas/síntese química , RNA Bacteriano/metabolismo , Sideróforos/metabolismo
17.
Anal Biochem ; 454: 36-7, 2014 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-24632099

RESUMO

The following report describes a simple and optimized assay for the detection of iron in solution based on the binding of this metal by ferrozine. This assay accurately measures between 1 and 200 µM sample iron concentrations within 2½ hours.


Assuntos
Técnicas de Química Analítica/métodos , Ferrozina/química , Ferro/análise , Ferro/química , Absorção Fisico-Química , Limite de Detecção
18.
PLoS One ; 8(12): e83031, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24340076

RESUMO

Previous studies have suggested that sugars enhance iron bioavailability, possibly through either chelation or altering the oxidation state of the metal, however, results have been inconclusive. Sugar intake in the last 20 years has increased dramatically, and iron status disorders are significant public health problems worldwide; therefore understanding the nutritional implications of iron-sugar interactions is particularly relevant. In this study we measured the effects of sugars on non-heme iron bioavailability in human intestinal Caco-2 cells and HepG2 hepatoma cells using ferritin formation as a surrogate marker for iron uptake. The effect of sugars on iron oxidation state was examined by measuring ferrous iron formation in different sugar-iron solutions with a ferrozine-based assay. Fructose significantly increased iron-induced ferritin formation in both Caco-2 and HepG2 cells. In addition, high-fructose corn syrup (HFCS-55) increased Caco-2 cell iron-induced ferritin; these effects were negated by the addition of either tannic acid or phytic acid. Fructose combined with FeCl3 increased ferrozine-chelatable ferrous iron levels by approximately 300%. In conclusion, fructose increases iron bioavailability in human intestinal Caco-2 and HepG2 cells. Given the large amount of simple and rapidly digestible sugars in the modern diet their effects on iron bioavailability may have important patho-physiological consequences. Further studies are warranted to characterize these interactions.


Assuntos
Epitélio/efeitos dos fármacos , Intestinos/efeitos dos fármacos , Ferro/farmacocinética , Fígado/efeitos dos fármacos , Disponibilidade Biológica , Células CACO-2 , Sacarose na Dieta/química , Ferritinas/química , Ferrozina/química , Frutose/química , Glucose/química , Células Hep G2 , Humanos , Adoçantes Calóricos/química , Ácido Fítico/química , Sacarose/química , Taninos/química , Zea mays
19.
J Microbiol Methods ; 95(3): 366-7, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24140574

RESUMO

The ferrozine assay is a widely used colorimetric method for determining soluble iron concentrations. We provide evidence for a heretofore unrecognized interference of ferric ions (Fe(3+)) on ferrous iron (Fe(2+)) measurements performed in the dark. Fe(3+) concentrations affected the absorbance measurements, which linearly increased with incubation time.


Assuntos
Técnicas de Química Analítica , Colorimetria/métodos , Compostos Férricos/metabolismo , Compostos Ferrosos/análise , Ferrozina/metabolismo , Ferro/análise , Escuridão , Erros de Diagnóstico , Íons/análise , Fatores de Tempo
20.
Int J Pharm ; 457(1): 177-86, 2013 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-24076399

RESUMO

Rutin, the glycoside of quercetin, could be used in topical preparations because of its antioxidant and radical scavenging properties, but its employ in cosmetic and pharmaceutical products is limited by poor physico-chemical stability. These issues were addressed by preparing, characterizing and testing rutin inclusion complexes with MCM-41 mesoporous silica. The effect of surface functionalization with aminopropyl groups (NH2-MCM-41) on the molecules properties was studied. The organic/inorganic interaction was confirmed by many techniques. In particular, the high inclusion of rutin in the pores of NH2-MCM-41 was assessed by XRD, TGA, gas-volumetric analysis (BET), while FTIR spectroscopy allowed to analyse with great detail the molecular interaction with the inorganic surface. Rutin was stabilized against UV degradation, mostly by its inclusion in NH2-MCM-41. Ex vivo studies showed a greater accumulation in porcine skin in the case of rutin complexed with NH2-MCM-41. Not only antioxidant properties of rutin were maintained after immobilization but, with aminopropyl silica, the metal-chelating activity increased noticeably. The immobilization of rutin in aminopropyl silica resulted in better performance in terms of activity and photostability, suggesting the importance of functionalization in stabilizing organic molecules within silica pores.


Assuntos
Antioxidantes/química , Quelantes/química , Rutina/química , Dióxido de Silício/química , Administração Tópica , Animais , Antioxidantes/administração & dosagem , Antioxidantes/efeitos da radiação , Quelantes/administração & dosagem , Quelantes/efeitos da radiação , Ferrozina/química , Técnicas In Vitro , Rutina/administração & dosagem , Rutina/efeitos da radiação , Dióxido de Silício/administração & dosagem , Dióxido de Silício/efeitos da radiação , Pele/metabolismo , Absorção Cutânea , Propriedades de Superfície , Suínos , Raios Ultravioleta
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