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1.
PLoS One ; 15(6): e0233844, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32492068

RESUMO

The hydrophobicity of nanoparticles (NPs) is a key property determining environmental fate, biological partitioning and toxicity. However, methods to characterize surface hydrophobicity are not uniformly applied to NPs and cannot quantify surface changes in complex environments. Existing methods designed to evaluate the hydrophobicity of bulk solids, chemicals, and proteins have significant limitations when applied to NPs. In this study, we modified and evaluated two methods to determine the hydrophobicity of NPs, hydrophobic interaction chromatography (HIC) and dye adsorption, and compared them to the standard octanol-water partitioning protocol for chemicals. Gold, copper oxide, silica, and amine-functionalized silica NPs were used to evaluate methods based on their applicability to NPs that agglomerate and have surface coatings. The octanol water partitioning and HIC methods both measured Au NPs as hydrophilic, but despite having a small size and stable suspension, NPs could not be fully recovered from the HIC column. For the dye adsorption method, hydrophobic (Rose Bengal) and hydrophilic (Nile Blue) dyes were adsorbed to the NP surface, and linear isotherm parameters were used as a metric for hydrophobicity. CuO was determined to be slightly hydrophilic, while SiO2 was hydrophilic and Ami-SiO2 was hydrophobic. The advantages and limitations of each method are discussed, and the dye adsorption method is recommended as the most suitable for application across broad classes of nanomaterials. The dye assay method was further used to measure changes in the surface hydrophobicity of TiO2 NPs after being suspended in natural water collected from the Alsea Rivers watershed in Oregon. TiO2 NPs adsorbed Rose Bengal when suspended in ultrapure water, but adsorbed Nile Blue after being incubated in natural water samples, demonstrating a shift from hydrophobic to hydrophilic properties on the outer surface. The dye adsorption method can be applied to characterize surface hydrophobicity of NPs and quantify environmental transformations, potentially improving environmental fate models.


Assuntos
Cromatografia/métodos , Corantes Fluorescentes/química , Interações Hidrofóbicas e Hidrofílicas , Nanopartículas/química , Oxazinas/química , Rosa Bengala/química , Espectrometria de Fluorescência/métodos , Adsorção , Cobre/química , Ouro/química , Dióxido de Silício/química , Propriedades de Superfície
2.
Mar Pollut Bull ; 153: 110982, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32275539

RESUMO

Microplastics ingested by two bivalve species Perna viridis and Meretrix meretrix collected from three estuaries viz. Ariyankuppam, Panithittu, and Chunnambar in Pondicherry, India was analysed for the first time in this research. Nile Red dye was used for microplastic detection. A survey of 50 local families was conducted to determine the frequency and quantity in which they consume mussels/clams. On an average, the number of microplastics per gram of soft tissue (wet weight) is 0.18 ± 0.04, 1.84 ± 0.61, and 1.76 ± 0.48; and the number of microplastics per bivalve is 0.50 ± 0.11, 1.75 ± 0.35, and 4.80 ± 1.39 respectively for Ariyankuppam, Panithittu, and Chunnambar. 61.02% and 77.42% of the particles belonged to the size group of <100 µm in M. meretrix and P. viridis respectively. A moderate positive correlation of r (18) = 0.6985, p < 0.05 was calculated between bivalve weight and microplastic particles. An average person belonging to the local community is likely to ingest 3917.79 ± 144.71 microplastic particles per year through mussel consumption.


Assuntos
Monitoramento Ambiental/métodos , Microplásticos , Perna (Organismo) , Poluentes Químicos da Água , Animais , Dieta , Estuários , Índia , Oxazinas/química , Plásticos
3.
J Environ Sci (China) ; 89: 23-34, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31892395

RESUMO

Chloroacetamide herbicides, namely acetochlor and metolachlor, are common herbicides used on corn and soybean fields. Dichloroacetamide safeners, namely benoxacor and furilazole, are commonly used in formulations containing chloroacetamide herbicides. Extensive reports on adsorption of chloroacetamide herbicides are available, yet little information exists regarding adsorption potential of co-applied safeners. Herein, the adsorption and desorption characteristics of selected herbicide safeners to granular activated carbon (GAC) and in agricultural soils are reported. Further, soil column studies were performed to understand the leaching behaviour of the herbicide Dual II Magnum. Equilibrium sorption experiments of safeners to three agricultural soils and one GAC showed that adsorption was best fitted by the Freundlich isotherm. The Freundlich adsorption constant, Kf, for benoxacor and furilazole sorption onto three agricultural soils ranged from 0.1 to 0.27 and 0.1 to 0.13 (mg/g) × (mg/L)ˆ(1/n), respectively. The Kf for benoxacor and furilazole to GAC was 6.4 and 3.4 (mg/g) × (mg/L)ˆ(1/n), respectively, suggesting more favorable sorption of benoxacor to GAC than furilazole to GAC. The sorption to soils was reversible as almost 40%-90% of both safeners was desorbed from three soils. These results were validated in four replicated soil column studies, where S-metolachlor was shown to leach similarly to the safener benoxacor, originating from the herbicide formulation. The leaching of S-metolachlor and benoxacor was influenced by soil texture. Cumulatively, these results show that safeners will move through the environment to surface waters similarly to the active ingredients in herbicides, but may be removed during drinking water treatment via GAC.


Assuntos
Herbicidas/química , Poluentes do Solo/química , Adsorção , Carvão Vegetal/química , Cinética , Oxazinas/química , Solo
4.
Anal Chim Acta ; 1098: 86-93, 2020 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-31948590

RESUMO

Cytochrome P450 (CYP450), and in particular CYP3A4, is the most abundantly expressed CYP450 isozyme implicated in many drug-drug and medicinal plant-drug interactions. Therefore, incorporation of CYP3A4 enzyme screening at an early stage of drug discovery is preferable in order to avoid enzymatic interactions. Here we present for the first time a paper-based CYP3A4 immobilized sol-gel-derived a platform using resorufin benzyl ether as a fluorogenic enzyme substrate used to investigate enzyme activity. The fluorescence intensity of the product can be simply quantified by using a handheld digital microscope and an image analysis software. The limit of quantitation was 0.35 µM with good precision (RSDs < 4.1%). Furthermore, the assay of CYP3A4 activity on the developed paper-based device provided comparable results with those obtained from conventional well-plates (p > 0.05), while offering simplicity and lower cost. Kinetic parameters of the immobilized CYP3A4 in sol-gel coated paper were calculated from the Lineweaver-Burk plot, including Michaelis constant (Km) and maximum velocity (Vmax), which were 2.71 ±â€¯0.35 µM and 0.43 ±â€¯0.05 µM/min, respectively. Moreover, a functional test of these devices was conducted by assessments of known CYP3A4 inhibitors (i.e. ketoconazole, itraconazole) and inducers (i.e. phenytoin, carbamazepine). To further demonstrate the broad range of uses, the devices were utilized to assay plant extracts i.e. Areca catechu seeds, Camellia sinensis leaves, Eclipta prostrata aerial part, providing results in good agreement with previous studies. Furthermore, the sol-gel immobilized enzyme stored at 4 °C can increase storage stability, offering the activity of 86.3 ±â€¯0.4% after 3-weeks storage, equivalent to the activity of the free enzyme solution after 1-week storage. The developed paper-based devices offer versatility, portability and low-cost.


Assuntos
Derivados de Benzeno/química , Sistema Enzimático do Citocromo P-450/análise , Enzimas Imobilizadas/análise , Éteres/química , Oxazinas/química , Papel , Sistema Enzimático do Citocromo P-450/metabolismo , Ativação Enzimática , Enzimas Imobilizadas/metabolismo , Géis/química , Humanos , Estrutura Molecular
5.
Biomed Chromatogr ; 34(1): e4697, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31495945

RESUMO

A liquid chromatography electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) method was developed and validated to measure GDC-0084 in human plasma and cerebrospinal fluid (CSF). Reverse-phase chromatography with gradient elution was performed using a C18 column (50 × 2.0 mm, 3 µm). Solid-phase extraction of plasma and CSF was employed to give excellent recovery. MS detection was performed with positive ion screening in multiple reaction monitoring mode. The precursor to the product ions (Q1 → Q3) selected for GDC-0084 and GDC-0084-d6 were 383.2 → 353.2 and 389.2 → 353.2, respectively. A separate calibration curve was established for human plasma and CSF. Both calibration curves, ranging from 0.2 to 200 ng/mL, were linear and had acceptable intra- and inter-day precision and accuracy. The lower limit of quantitation and limit of detection for GDC-0084 in human plasma were 0.2 ng/mL (signal/noise ≥47) and 0.005 ng/mL (signal/noise ≥3.5), respectively, and for GDC-0084 in human CSF were 0.2 ng/mL (signal/noise ≥19.7) and 0.04 ng/mL (signal/noise ≥7.2). This method was successfully applied to analyze serial plasma samples obtained from children with diffuse intrinsic pontine gliomas and other midline gliomas who participated in pharmacokinetic studies as part of a phase I clinical trial of GDC-0084.


Assuntos
Cromatografia Líquida/métodos , Oxazinas/sangue , Oxazinas/líquido cefalorraquidiano , Pirimidinas/sangue , Pirimidinas/líquido cefalorraquidiano , Espectrometria de Massas em Tandem/métodos , Criança , Estabilidade de Medicamentos , Humanos , Limite de Detecção , Modelos Lineares , Oxazinas/química , Oxazinas/farmacocinética , Pirimidinas/química , Pirimidinas/farmacocinética , Reprodutibilidade dos Testes , Espectrometria de Massas por Ionização por Electrospray/métodos
6.
Chem Biol Interact ; 315: 108868, 2020 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-31669321

RESUMO

The extensive use of silver nanoparticles (AgNPs) in manufactured products will inevitably increase environmental exposure, highlighting the importance of accurate toxicity assessments. A frequent strategy to estimate AgNP cytotoxicity is to use absorbance or fluorescent-based assays. In this study we report that AgNPs - with or without surface functionalizations (polyvinyl pyrrolidone or gum arabic), and of different sizes (2-15 nm) - can interfere with the spectrometric quantification of different dyes commonly used in cytotoxicity assays, such as 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), neutral red (NR), Hoechst, and Resazurin. Some AgNP types caused more interference than others, which was dependent on the assay. Overall most AgNPs caused the direct reduction of MTT, as well as Hoechst and NR fluorescence quenching, and absorbed light at the same wavelength as NR. None of the AgNPs tested caused the direct reduction of Resazurin; however, depending on AgNP characteristics and concentration, they may still promote fluorescence quenching of this dye. Our results show that AgNPs with different size and coatings can interfere with spectroscopy-based assays to different degrees, suggesting that their cytotoxicity may be underestimated or overestimated. We suggest that when using any spectroscopy-based assay it is essential that each individual nanoparticle formulation be tested first for potential interferences at all intended concentrations.


Assuntos
Nanopartículas Metálicas/administração & dosagem , Nanopartículas Metálicas/química , Vermelho Neutro/química , Oxazinas/química , Prata/química , Prata/farmacologia , Sais de Tetrazólio/química , Tiazóis/química , Xantenos/química , Animais , Bioensaio/métodos , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Corantes , Camundongos , Tamanho da Partícula , Povidona/química , Propriedades de Superfície/efeitos dos fármacos
7.
Eur J Med Chem ; 187: 111960, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31869654

RESUMO

A series of l-lysine-conjugated pyridophenoxazinones 2-5 and 2'-5' were designed and synthesized for developing compounds with multimodal anticancer potentialities. All compounds inhibited the proliferation of a panel of human liquid and solid neoplastic cell lines. 2 and 5 were the most active compounds with IC50 values in the submicromolar range. UV-vis, 1H NMR, unwinding, and docking experiments demonstrated that they intercalate between the middle 5'-GC-3' base pairs with the carboxamide side chain lying into major groove. Charge-transfer contribution to the complex stability, evaluated by ab initio calculations, was found to correlate with cytotoxicity. Relaxation and cleavage assays showed that 2 and 5 selectively target Topo IIα over Topo IIß and stimulate the formation of covalent Topo II-DNA complexes, functioning as poisons. Moreover, compound 5 induced DNA damage and arrested MCF-7 cells at the G2/M phase. Altogether, the work provides interesting structure-activity relationships in the pyridophenoxazinone-l-lysine conjugate series and identifies 5 as a promising candidate for further in vivo evaluation.


Assuntos
Antineoplásicos/farmacologia , DNA Topoisomerases Tipo II/metabolismo , DNA de Neoplasias/efeitos dos fármacos , Lisina/farmacologia , Oxazinas/farmacologia , Inibidores da Topoisomerase II/farmacologia , Antineoplásicos/síntese química , Antineoplásicos/química , Sítios de Ligação/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Ligantes , Modelos Lineares , Lisina/química , Modelos Moleculares , Estrutura Molecular , Oxazinas/química , Relação Estrutura-Atividade , Inibidores da Topoisomerase II/síntese química , Inibidores da Topoisomerase II/química
8.
N Biotechnol ; 54: 71-79, 2020 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-31473254

RESUMO

The heme domain of cytochrome P450 116B5 from Acinetobacter radioresistens (P450 116B5hd), a self-sufficient class VII P450, was functionally expressed in Escherichia coli, purified and characterised in active form. Its unusually high reduction potential (-144 ±â€¯42 mV) and stability in the presence of hydrogen peroxide make this enzyme a good candidate for driving catalysis with the so-called peroxide shunt, avoiding the need for a reductase and the expensive cofactor NAD(P)H. The enzyme is able to carry out the peroxide-driven hydroxylation of aromatic compounds such as p-nitrophenol (KM = 128.85 ±â€¯29.51 µM and kcat = 2.65 ±â€¯0.14 min-1), 10-acetyl-3,7-dihydroxyphenoxazine (KM = 6.01 ±â€¯0.32 µM and kcat = 0.33 ±â€¯0.03 min-1), and 3,5,3',5'tetramethylbenzidine (TMB). Moreover, it catalyses different reactions on well-known drugs such as hydroxylation of diclofenac (KM = 49.60 ±â€¯6.30 µM and kcat = 0.06 ±â€¯0.01 min-1) and N-desmethylation of tamoxifen (KM = 57.20 ±â€¯7.90 µM and kcat = 0.79 ±â€¯0.04 min-1). The data demonstrate that P450 116B5hd is an efficient biocatalyst for sustainable applications in bioremediation and human drug metabolite production.


Assuntos
Acinetobacter/enzimologia , Benzidinas/metabolismo , Biocatálise , Sistema Enzimático do Citocromo P-450/metabolismo , Nitrofenóis/metabolismo , Oxazinas/metabolismo , Peróxidos/metabolismo , Benzidinas/química , Sistema Enzimático do Citocromo P-450/química , Sistema Enzimático do Citocromo P-450/isolamento & purificação , Escherichia coli/metabolismo , Heme/química , Heme/metabolismo , Estrutura Molecular , Nitrofenóis/química , Oxazinas/química , Oxirredução , Peróxidos/química
9.
Eur J Med Chem ; 185: 111771, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31671309

RESUMO

This work describes a straightforward diastereoselective synthetic access to azirino[2,1-b]benzo[e][1,3]oxazines containing phosphorus substituents such as phosphonate or phosphine oxide, by means of nucleophilic addition of functionalized phenols to the C-N double bond of 2H-azirine derivatives. In addition, the cytotoxic effect on cell lines derived from human lung adenocarcinoma (A549) and human embryonic kidney (HEK293) was also screened. Some azirino[2,1-b]benzo[e][1,3]oxazines 4 and 6 exhibited very good activity against the A549 cell line in vitro. Furthermore, selectivity towards cancer cell (A549) over (HEK293), and non-malignant cells (MCR-5) has been detected.


Assuntos
Antineoplásicos/farmacologia , Oxazinas/farmacologia , Células A549 , Antineoplásicos/síntese química , Antineoplásicos/química , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Células HEK293 , Humanos , Estrutura Molecular , Oxazinas/síntese química , Oxazinas/química , Fosforilação , Relação Estrutura-Atividade
10.
J Enzyme Inhib Med Chem ; 35(1): 50-58, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31656107

RESUMO

GPR119 is a promising target for discovery of anti-type 2 diabetes mellitus agents. We described the optimisation of a novel series of pyrimido[5,4-b][1,4]oxazine derivatives as GPR119 agonists. Most designed compounds exhibited good agonistic activities. Among them, compound 10 and 15 demonstrated the potent EC50 values (13 and 12 nM, respectively) and strong inherent activities. Moreover, significant hypoglycaemic effect of compound 15 was observed by reducing the blood glucose AUC0-2h at the dose of 30 mg/kg, which is stronger than Vildagliptin (23.4% reduction vs. 17.9% reduction).


Assuntos
Hipoglicemiantes/farmacologia , Oxazinas/farmacologia , Pirimidinas/farmacologia , Receptores Acoplados a Proteínas-G/agonistas , Animais , Glicemia/efeitos dos fármacos , Relação Dose-Resposta a Droga , Teste de Tolerância a Glucose , Humanos , Hipoglicemiantes/síntese química , Hipoglicemiantes/química , Camundongos , Camundongos Endogâmicos C57BL , Estrutura Molecular , Oxazinas/síntese química , Oxazinas/química , Pirimidinas/síntese química , Pirimidinas/química , Relação Estrutura-Atividade
11.
Mater Sci Eng C Mater Biol Appl ; 107: 110323, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31761237

RESUMO

Inspired by traditional pH papers, two types of ratiometric fluorescent pH sensors for neutral and alkaline pH ranges were developed in this study by using two fluorescent dyes, coumarin 6 (C6) and nile blue A (NB). These dyes were encapsulated into melamine-formaldehyde (MF) resin particles, which were then incorporated with polymer Nafion (Nf) or polyurethane hydrogel (PU) to prepare pH-sensing membranes. MF-C6 particles immobilized into polymer Nafion (i.e., MF-C6-Nf membrane) showed a dynamic ratiometric pH detection range of 4.5-7.5 through shift in fluorescence emission spectra at acidic and neutral pH solutions, as well as distinct color transition under normal visual sense from pink to yellow color. By contrast, MF-NB particles immobilized into polyurethane hydrogel (i.e., MF-NB-PU membrane) displayed a dynamic ratiometric fluorescence detection range of pH 9 - pH 12 via change in ratiometric fluorescence intensity at two emission band edges. The membrane also showed a clear change from blue to purple color under sunlight at high pH values. These pH-sensing membranes also exhibited high sensitivity, good reversibility, and stability. They were then applied to measure pH values in real urine samples and fermentation media.


Assuntos
Cumarínicos/química , Oxazinas/química , Espectrometria de Fluorescência/métodos , Tiazóis/química , Urinálise/métodos , Actinobacteria/crescimento & desenvolvimento , Cor , Fermentação , Corantes Fluorescentes , Humanos , Concentração de Íons de Hidrogênio , Membranas Artificiais , Sensibilidade e Especificidade , Triazinas/química , Urinálise/instrumentação
12.
Mar Pollut Bull ; 143: 152-162, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31789151

RESUMO

Microplastics (MP) are detected in aquatic environments worldwide, yet detection is often limited to larger sized MP. To address this data gap, the abundance of MP 3-500 µm was assessed in the Los Angeles River, the San Gabriel River, and the Long Beach Harbor (CA, USA), three areas with highly urbanized surroundings. Whole surface water samples were taken, subjected to a hydrogen peroxide digestion and MP counts were compared between unstained visual examination and Nile Red staining identification techniques. The largest concentration of MP was found in the Los Angeles River, where 13,622 MP m-3 were found using unstained visual examination and 641,292 MP m-3 were found utilizing Nile Red staining. The protocol used to detect smaller sized MP is low cost, time efficient, and reproducible. This work highlights the need for more extensive sampling of smaller sized MP globally and universal testing and reporting standards for MP detection.


Assuntos
Monitoramento Ambiental/métodos , Microplásticos/análise , Poluentes Químicos da Água/análise , California , Monitoramento Ambiental/economia , Microplásticos/química , Oxazinas/química , Controle de Qualidade , Rios , Urbanização , Poluentes Químicos da Água/química
13.
Molecules ; 24(24)2019 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-31835604

RESUMO

Questiomycin A (1) along with three new compounds, questiomycins C-E (2-4), were isolated from culture of Alteromonas sp. D, an algicidal marine bacterium, guided by algal lethality assay using the raphidophyte, Chattonella antiqua, one of the causative organisms of harmful algal bloom. The structures of 1-4 were assigned on the basis of their spectrometric and spectroscopic data. Compounds 1 to 4 exhibited algicidal activity against C. antiqua with LC50 values ranging from 0.18 to 6.37 M. Co-cultivation experiment revealed that 1 was produced only when the microalgae and the bacterium are in close contact, suggesting that some interactions between them trigger the biosynthesis of questiomycins. These results suggested that the algicidal bacteria such as Alteromonas sp. D can control microalgae chemically in marine ecosystem.


Assuntos
Alteromonas/metabolismo , Antibacterianos/biossíntese , Organismos Aquáticos/metabolismo , Oxazinas/metabolismo , Antibacterianos/química , Antibacterianos/isolamento & purificação , Cromatografia Líquida , Sinais (Psicologia) , Proliferação Nociva de Algas , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Testes de Sensibilidade Microbiana , Estrutura Molecular , Oxazinas/química , Oxazinas/isolamento & purificação
14.
Int J Pharm ; 572: 118812, 2019 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-31715343

RESUMO

Information about the solid-state properties of etifoxine has been lacking, even if the active pharmaceutical ingredient has been used for its anxiolytic properties for decennia. The crystal structure of the racemic compound possesses a monoclinic space group P21/n with cell parameters a = 8.489(2) Å, b = 17.674(2) Å, c = 20.883(3) Å, ß = 98.860(10)° and a unit-cell volume of 3095.8(9) Å3 at 293 K. The unit cell contains 8 molecules, while 2 independent molecules with different conformations are present in the asymmetric unit. The density of the crystal is 1.291 g/cm3 and its melting point was found at 362.6 ±â€¯0.3 K with a melting enthalpy of 85.6 ±â€¯3.0 J g-1. Its thermal expansion in the liquid and the solid state and the change in volume on melting and between the vitreous state and the crystalline solid have been studied. The results confirm the tendency of small organic molecules to increase about 11% in volume on melting, while the volume difference between the glass and the crystal at the glass transition temperature is about half this value at 6%. These values can be used in the construction of phase diagrams in the case that the experimental data for a given system is incomplete.


Assuntos
Ansiolíticos/química , Química Farmacêutica , Oxazinas/química , Cristalização , Transição de Fase , Pressão , Estereoisomerismo , Temperatura , Termodinâmica , Temperatura de Transição
15.
Analyst ; 144(24): 7263-7269, 2019 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-31691682

RESUMO

A novel hypochlorous-acid-selective signaling probe based on the carbonodithioate derivative of resorufin (RT-1) was developed. Probe RT-1 showed prominent colorimetric and turn-on type fluorescence signaling behavior exclusively toward hypochlorous acid, induced by oxidative hydrolysis, to regenerate resorufin dye. Hypochlorous acid signaling was not affected by the presence of common metal ions and anions as background, except for the redox active bromide and iodide anions. The detection limit of RT-1 for hypochlorous acid was found to be 2.18 × 10-9 M (0.11 ppb), and the signaling was completed within 3 min. It was also confirmed that hypochlorous acid signaling by the carbonodithioate-based probe RT-1 was superior to that of the closely related carbonothioate derivative RT-2. This was rationalized by density functional theory calculations, which demonstrated that the C[double bond, length as m-dash]S sulfur atom of the former is more negatively charged than that of the latter. Finally, as a biological application of the probe, visualization of hypochlorous acid in RAW 264.7 murine macrophages and HeLa cells was successfully conducted to detect the cellular response to hypochlorous acid.


Assuntos
Corantes Fluorescentes/química , Ácido Hipocloroso/análise , Oxazinas/química , Animais , Sobrevivência Celular/efeitos dos fármacos , Colorimetria/métodos , Corantes Fluorescentes/síntese química , Corantes Fluorescentes/toxicidade , Células HeLa , Humanos , Limite de Detecção , Camundongos , Microscopia Confocal/métodos , Microscopia de Fluorescência/métodos , Oxazinas/síntese química , Oxazinas/toxicidade , Células RAW 264.7
16.
Molecules ; 24(19)2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31581424

RESUMO

A one-pot route to 2-alkyl and 2-aryl-4H-benzo[d][1,3]oxazin-4-ones (also known as 4H-3,1-benzoxazin-4-ones) has been developed and studied. The method involves the reaction of aryl-substituted anthranilic acids with orthoesters in ethanol catalyzed by acetic acid. Additionally, we have also investigated the reaction under microwave conditions. Not all of the substrates were successful in yielding the target heterocycles as some of the reactions failed to undergo the final elimination. This process led to the isolation of (±)-2-alkyl/aryl-2-ethoxy-1,2-dihydro-4H-benzo[d][1,3]oxazin-4-ones. The formation of the dihydro analogs correlated with the electron density on the aromatic ring: Electron-donating groups favored the 4H- benzo[d][1,3]oxazin-4-ones, while electron-withdrawing groups tended to favor the dihydro product. Substituting a pyridine ring for the benzene ring in the substrate acid suppressed the reaction.


Assuntos
Benzoatos/síntese química , Oxazinas/química , ortoaminobenzoatos/química , Benzoatos/química , Catálise , Compostos Heterocíclicos/síntese química , Compostos Heterocíclicos/química , Estrutura Molecular , Relação Estrutura-Atividade
17.
Chem Pharm Bull (Tokyo) ; 67(10): 1123-1130, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31582632

RESUMO

The adenosine triphosphate derivatives of 2-oxo-1,3-diazaphenoxazine (dAdapTP) showed a significant discrimination ability for the template strand including that between 8-oxo-2'-deoxyguanosine (8-oxodG) and 2'-deoxyguanosine (dG) by the single nucleotide primer extension reaction using the Klenow Fragment. In this study, we synthesized new dAdapTP derivatives, i.e., 2-amino-dAdapTP, 2-chloro-dAdapTP and 2-iodo-dAdapTP, to investigate the effect on the selectivity and efficiency of incorporation for the primer extension reaction using a variety of DNA polymerases. In contrast to the previously tested dAdapTP, the selectivity and efficiency of the 2-halo-dAdapTP incorporation were dramatically decreased using the Klenow Fragment. Moreover, the efficiency of the 2-amino-dAdapTP incorporation into the T-containing template was almost the same with that of dAdapTP. In the case of the Bsu DNA polymerase, the efficiency of all the dAdapTP derivatives decreased compared to that using the Klenow Fragment. However, the incorporation selectivity of dAdapTP had improved against the oxodG-containing template for all the template sequences including the T-containing template. Moreover, 2-amino-dAdapTP showed a better efficiency than dAdapTP using the Bsu DNA polymerase. The 2-amino group of the adenosine unit may interact with syn-oxodG at the active site of the Bsu DNA polymerase during the single primer extension reaction.


Assuntos
Adenosina/metabolismo , Compostos Aza/metabolismo , DNA Polimerase Dirigida por DNA/metabolismo , Oxazinas/metabolismo , Polifosfatos/metabolismo , 8-Hidroxi-2'-Desoxiguanosina , Adenosina/química , Compostos Aza/química , DNA Polimerase Dirigida por DNA/química , Desoxiguanosina/análogos & derivados , Desoxiguanosina/química , Desoxiguanosina/metabolismo , Estrutura Molecular , Oxazinas/química , Polifosfatos/química
18.
Nucl Med Biol ; 74-75: 41-48, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31473491

RESUMO

INTRODUCTION: Fluorine-18 labeled radiopharmaceuticals undergo quality control testing for residual phase-transfer-catalyst content. The almost universally used quality-control test is a silica plate spot-test comparison of the radiopharmaceutical beside a 50-ppm standard. Once developed by staining, the radiopharmaceutical spot must be of equal or less intensity to pass the test. There is currently a need for a quantitative, inexpensive, and less subjective quality control method that allows the automatic incorporation of the acquired measurement directly into electronic batch reports. RESULTS: In the developed method, a resazurin test solution is mixed with an aliquot of the radiopharmaceutical analyte along with dichloromethane (DCM). The mixture is vortexed. The potassium resazurin-phase transfer catalyst complex solubilizes into the DCM imparting a blue color. The organic layer is then removed for analysis. Three measurement methods were utilized: visual colorimetry against pre-prepared standards, spectrophotometric measurement of transmittance, and electrical conductance. A simple prototype spectrophotometer and an electrical test cell were constructed to acquire data. Sodium Resazurin dye was found to be a suitable test chromophore for residual phase transfer catalyst analysis of aqueous solutions. Quantitative spectrophotometric measurements are possible in the 0-100-ppm range (18-crown-6) and 0-150-ppm range (Kryptofix® or tetrabutylammonium). Electrical resistance measurements of the phase transfer-catalyst resazurin complex in DCM are also a viable method, allowing quantitative phase transfer catalyst measurements in the 0-100-ppm range. CONCLUSION: The methodologies developed are more quantitative alternatives to the current spot-test method. The spectrophotometric method was determined to be the most accurate method.


Assuntos
Calorimetria/métodos , Radioisótopos de Flúor/análise , Indicadores e Reagentes/química , Oxazinas/química , Compostos Radiofarmacêuticos/análise , Solventes/química , Espectrofotometria/métodos , Xantenos/química , Humanos
19.
Colloids Surf B Biointerfaces ; 184: 110478, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31541890

RESUMO

The incidence of Acute Lymphoblastic Leukemia (ALL) is increasing globally, and it is being clinically addressed by chemotherapy, followed by immunotherapy and stem cell transplantation, all with potential life-threatening toxicities. In the need for more effective therapeutics, newly developed disease-targeted nanocompounds can thus hold real potential. In this paper, we propose a novel nanoparticle-based immunotherapeutic agent against ALL, consisting of antiCD19 antibody-conjugated, polyethylene glycol (PEG)-biocompatibilized, and Nile Blue (NB) Raman reporter-tagged gold nanoparticles of urchin-like shape (GNUs), that have a plasmonic response in the Near Infrared (NIR) spectral range. Transmission electron microscopy (TEM) images of particle-incubated CD19-positive (CD19(+)) CCRF-SB cells show that the antiCD19-PEG-NB-GNU nanocomplex is able to recognize the CD19 B-cell-specific antigen, which is a prerequisite for targeted therapy. The therapeutic effect of the particles is confirmed by cell counting, combined with cell cycle analysis by flow cytometry and MTS assay, which additionally offer insights into their mechanisms of action. Specifically, antiCD19-PEG-NB-GNUs proved superior cytotoxic effect against CCRF-SB cells when compared with the free antibody, by reducing the overall viability below 18% after 7 days treatment at a particle-bound antibody concentration of 0.17 ng/µl. Moreover, by combining their remarkable plasmonic properties with the possibility of Raman tagging, the proposed nanoparticles can also serve as spectroscopic imaging agents inside living cells, which validates their theranostic potential in the field of hematological oncology.


Assuntos
Antígenos CD19/imunologia , Ouro/química , Imunoconjugados/administração & dosagem , Nanopartículas Metálicas/administração & dosagem , Leucemia-Linfoma Linfoblástico de Células Precursoras/terapia , Antineoplásicos/administração & dosagem , Antineoplásicos/química , Apoptose/efeitos dos fármacos , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Humanos , Imunoconjugados/química , Imunoterapia/métodos , Nanopartículas Metálicas/química , Nanopartículas Metálicas/ultraestrutura , Microscopia Eletrônica de Transmissão , Oxazinas/química , Polietilenoglicóis/química , Leucemia-Linfoma Linfoblástico de Células Precursoras/patologia , Análise Espectral Raman
20.
Sensors (Basel) ; 19(19)2019 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-31546587

RESUMO

Rapid and sensitive detection of botulinum neurotoxins (BoNTs) is important for immediate treatment with proper antitoxins. However, it is difficult to detect BoNTs at the acute phase of infection, owing to its rarity and ambiguous symptoms. To resolve this problem, we developed a surface-enhanced Raman scattering (SERS)-based immunoassay technique for the rapid and sensitive detection of BoNTs. Magnetic beads and SERS nanotags as capture substrates and detection probes, respectively, and Nile Blue A (NBA) and malachite green isothiocyanate (MGITC) as Raman reporter molecules were used for the detection of two different types of BoNTs (types A and B), respectively. The corresponding limits of detection (LODs) were determined as 5.7 ng/mL (type A) and 1.3 ng/mL (type B). Total assay time, including that for immunoreaction, washing, and detection, was less than 2 h.


Assuntos
Toxinas Botulínicas/análise , Imunoensaio/métodos , Análise Espectral Raman/métodos , Bioterrorismo , Humanos , Isotiocianatos/química , Oxazinas/química
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