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1.
Anal Bioanal Chem ; 412(6): 1431-1439, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31912183

RESUMO

Triatominae are hematophagous insects involved in the transmission of Chagas disease. Among the 19 genera of the subfamily, those with the highest epidemiological importance regarding the dissemination of Trypanosoma cruzi are Panstrongylus, Rhodnius, and Triatoma. Of these three genera, Rhodnius presents the greatest difficulties for specific identification. Thus, there is a need to overcome the difficulties in identifying phenotypes of similar species of this genus. In the present study, the MALDI-TOF MS methodology was used to identify 12 Rhodnius species, among the 21 admitted. The MALDI-TOF MS methodology allowed specific characterization through the identification of peptides and proteins, starting from four different methods of extraction: (A) acetonitrile/formic acid (ACN/AF), (B) acetonitrile/trifluoroacetic acid (ACN/TFA), (C) isopropyl/formic acid (IPA/AF), and (D) methanol/formic acid (MeOH/AF), and four types of MALDI-TOF matrices: α-cyano-4-hydroxycinnamic acid (CHCA), sinapic acid (SA), 6-aza-2-thiothymine (ATT), and 2,6-dihydroxyacetophenone (DHAP). The experiments were performed by combining the four solvents and four matrices to select the best MALDI extraction/matrix. The application of the MALDI-TOF MS technique, through the digital mass spectrometry approach combined with chemometric tools, such as partial least squares-discriminant analysis (PLS-DA), was able to discriminate 12 species of Rhodnius genus, which are difficult to identify using morphological characteristics. Thus, in view of the results obtained, the methodology described in the present article can be applied with speed and efficiency for the discrimination of Triatominae species. Graphical Abstract.


Assuntos
Proteínas de Insetos/química , Peptídeos/química , Rhodnius/classificação , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Acetofenonas/química , Animais , Ácidos Cumáricos/química , Formiatos/química
2.
J Chromatogr A ; 1609: 460458, 2020 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-31443969

RESUMO

Pentacyclic triterpenoids (PCTs) possess high biological activity, including antitumor, anti-inflammatory, antiviral and hepatoprotective properties and are widespread in a plant biomass. Due to significant differences in polarity and other physicochemical properties, the simultaneous determination of different classes of PCTs by the methods of reversed phase liquid chromatography is difficult. In the present study, we proposed a new approach to chromatographic separation of such compounds based on the use of a stationary phase with a mixed retention mechanism combining hydrophobic, weak anion exchange and hydrophilic interactions. The use of the Acclaim Mixed-Mode WAX-1 column and tuning the selectivity by changing the contributions of different types of analyte-stationary phase interactions allowed the separation of 10 PCTs (betulin, erythrodiol, uvaol, friedelin, lupeol, ß-amyrin, α-amyrin, betulinic, oleanolic and ursolic acids) belonging to four different classes (monools, diols, ketones and triterpenic acids) during 7.5 min in isocratic elution mode. The combination of this approach with atmospheric pressure chemical ionization tandem mass spectrometric detection and pressurized liquid extraction of analytes with methanol allowed to develop a rapid, accurate and highly sensitive method for analyzing PCTs in plant tissues with a total duration of the analytical cycle (including sample preparation steps) of not more than 40 min. It provides the detection limits in plant biomass extracts of 3-12 µg L-1 (44 µg L-1 for friedelin). The developed method was validated and successfully tested in the analyses of real birch bark and lingonberry peels.


Assuntos
Cromatografia Líquida/métodos , Triterpenos Pentacíclicos/isolamento & purificação , Espectrometria de Massas em Tandem/métodos , Acetonitrilos/química , Betula/química , Biomassa , Calibragem , Formiatos/química , Concentração de Íons de Hidrogênio , Limite de Detecção , Concentração Osmolar , Triterpenos Pentacíclicos/química , Extratos Vegetais/química , Reprodutibilidade dos Testes , Vaccinium vitis-Idaea/química
3.
Eur J Med Chem ; 186: 111894, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31787361

RESUMO

Green chemistry is becoming the favored approach to preparing drug molecules in pharmaceutical industry. Herein, we developed a clean and efficient method to synthesize 3-benzoylquinoxalines via activated carbon promoted aerobic benzylic oxidation under "on-water" condition. Moreover, biological studies with this class of compounds reveal an antiproliferative profile. Further structure modifications are performed and the investigations exhibited that the most active 12a could inhibit the microtubule polymerization by binding to tubulin and thus induce multipolar mitosis, G2/M phase arrest, and apoptosis of cancer cells. In addition, molecular docking studies allow the rationalization of the pharmacodynamic properties observed. Our systematic studies provide not only guidance for applications of O2/AC/H2O system, but also a new scaffold targeting tubulin for antitumor agent discovery.


Assuntos
Antineoplásicos/farmacologia , Compostos de Benzil/química , Quinoxalinas/farmacologia , Tubulina (Proteína)/metabolismo , Antineoplásicos/síntese química , Antineoplásicos/química , Carbono/química , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Formiatos/química , Humanos , Modelos Moleculares , Estrutura Molecular , Oxirredução , Polimerização/efeitos dos fármacos , Quinoxalinas/síntese química , Quinoxalinas/química , Relação Estrutura-Atividade , Ácidos Sulfúricos/química , Ácido Trifluoracético/química
4.
Talanta ; 206: 120209, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31514865

RESUMO

A novel approach for dispersive liquid-liquid microextraction based on the use of deep eutectic solvent as a disperser was presented for the first time. The procedure was automated based on an in-syringe flow system coupled with UV-Vis detection and demonstrated by the determination of chromium (VI) in beverages. This analytical task was used as a proof-of-concept example. The automated extraction procedure involved the aspiration of aqueous sample into a syringe pump with homogeneous mixture of extraction solvent (1-oсtanol) and deep eutectic solvent (tetrabutylammonium bromide - formic acid) containing color-forming reagent (1,5-diphenylcarbazide). This led to decomposition of deep eutectic solvent in aqueous phase resulting in dispersion of extraction solvent, oxidation of 1,5-diphenylcarbazide to 1,5- diphenylcarbazone in the presence of chromium (VI), and formation of colored chromium (III) complex with 1,5-diphenylcarbazone and its fast extraction. In this case composition of deep eutectic solvent played a key role for analyte extraction. Tetrabutylammonium bromide promoted mass transfer between aqueous phase and the extraction solvent droplets as a salting out agent, bromide ion acted as an ion-pare agent for analyte complex extraction, formic acid provided required pH value for analyte complex formation. Under the optimal conditions the limit of detection, calculated from a blank test based on 3s, was 0.2 µg L-1. The automated dispersive liquid-liquid microextraction using deep eutectic solvent as disperser can be considered as an available, efficient, rapid and environmentally friendly sample pretreatment approach.


Assuntos
Cromo/análise , Contaminação de Alimentos/análise , 1-Octanol/química , Bebidas Gaseificadas/análise , Água Potável/análise , Formiatos/química , Sucos de Frutas e Vegetais/análise , Limite de Detecção , Microextração em Fase Líquida/instrumentação , Microextração em Fase Líquida/métodos , Malus/química , Prunus avium/química , Compostos de Amônio Quaternário/química , Solventes/química , Espectrofotometria Ultravioleta , Seringas
5.
Phys Chem Chem Phys ; 21(39): 21798-21805, 2019 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-31573010

RESUMO

Composites of the noble metal Au supported on MgAl-LDHs were prepared by a simple impregnation-reduction method to be used as thermal- and photocatalysts for the photocatalytic degradation of ciprofloxacin and thermocatalytic decomposition of formic acid to produce hydrogen. A collection of techniques, including X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) were employed to determine the structure and morphology properties of the as-prepared Au/MgAl-LDHs. The presence of surface Au(0) in Au/MgAl-LDHs was confirmed by TEM and XPS analyses. For the first time, we compared the effect of the surfactant PVP on the catalyst and found that the Au/MgAl-LDH composite with Au particle size of 2-8 nm had better catalytic activity than the (PVP@Au)/MgAl-LDH composite with Au particle size in the range of 1-5 nm. The sizes of Au NPs in the two catalysts were similar but had different effects on the catalytic performance. This indicated that the addition of PVP had an inhibitory effect on the catalytic activity of the catalyst. To evaluate the photostability of Au/MgAl-LDHs, recycle experiments for the photocatalytic degradation of ciprofloxacin were performed, and it was found that Au/MgAl-LDHs had good stability. Finally, we also applied Au/MgAl-LDHs in environmental catalysis and energy catalysis; we hope that they will be useful in practical applications.


Assuntos
Ligas/química , Alumínio/química , Ouro/química , Hidróxidos/química , Magnésio/química , Nanopartículas Metálicas/química , Adsorção , Catálise , Ciprofloxacino/química , Formiatos/química , Hidrogênio/química , Cinética , Oxirredução , Tamanho da Partícula , Processos Fotoquímicos , Propriedades de Superfície , Poluentes Químicos da Água/química
6.
Sensors (Basel) ; 19(19)2019 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-31569329

RESUMO

There is a growing desire for wearable sensors in health applications. Fibers are inherently flexible and as such can be used as the electrodes of flexible sensors. Fiber-based electrodes are an ideal format to allow incorporation into fabrics and clothing and for use in wearable devices. Electrically conducting fibers were produced from a dispersion of poly (3,4-ethylenedioxythiophene)-poly (styrenesulfonate) (PEDOT: PSS). Fibers were wet spun from two PEDOT: PSS sources, in three fiber diameters. The effect of three different chemical treatments on the fibers were investigated and compared. Short 5 min treatment times with dimethyl sulfoxide (DMSO) on 20 µm fibers produced from Clevios PH1000 were found to produce the best overall treatment. Up to a six-fold increase in electrical conductivity was achieved, reaching 800 S cm-1, with no loss of mechanical strength (150 MPa). With a pH-sensitive polyaniline coating, these fibers displayed a Nernstian response across a pH range of 3.0 to 7.0, which covers the physiologically critical pH range for skin. These results provide opportunities for future wearable, fiber-based sensors including real-time, on-body pH sensing to monitor skin disease.


Assuntos
Técnicas Eletroquímicas/instrumentação , Eletrodos , Poliestirenos/química , Solventes/química , Tiofenos/química , Dispositivos Eletrônicos Vestíveis , Dimetil Sulfóxido/química , Condutividade Elétrica , Técnicas Eletroquímicas/métodos , Formiatos/química , Concentração de Íons de Hidrogênio , Análise Espectral Raman , Ácidos Sulfúricos/química , Resistência à Tração
7.
Nat Commun ; 10(1): 4094, 2019 09 25.
Artigo em Inglês | MEDLINE | ID: mdl-31554785

RESUMO

The hydrogen isotope deuterium is widely used in the synthesis of isotopically-labeled compounds and in the fabrication of semiconductors and optical fibers. However, the facile production of deuterium gas (D2) and hydrogen deuteride (HD) in a controlled manner is a challenging task, and rational heterogeneously-catalyzed protocols are still lacking. Herein, we demonstrate the selective production of hydrogen isotope compounds from a combination of formic acid and D2O, through cooperative action by a PdAg nanocatalyst on a silica substrate whose surface is modified with amine groups. In this process, D2 is predominantly evolved by the assist of weakly basic amine moieties, while nanocatalyst particles in the vicinity of strongly basic amine groups promote the preferential formation of HD. Kinetic data and calculations based on semi-classically corrected transition state theory coupled with density functional theory suggest that quantum tunneling dominates the hydrogen/deuterium exchange reaction over the metallic PdAg surfaces.


Assuntos
Formiatos/química , Hidrogênio/farmacologia , Catálise , Preparações de Ação Retardada/farmacologia , Deutério/química , Óxido de Deutério/química , Hidrogenação , Nanopartículas/química , Água/química
8.
Top Curr Chem (Cham) ; 377(5): 27, 2019 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-31559502

RESUMO

The photocatalytic dehydrogenation of formic acid has recently emerged as an outstanding alternative to the traditional thermal catalysts widely applied in this reaction. The utilization of photocatalytic processes for the production of hydrogen is an appealing strategy that perfectly matches with the idea of a green and sustainable future energy scenario. However, it sounds easier than it is, and great efforts have been needed to design and develop highly efficient photocatalysts for the production of hydrogen from formic acid. In this work, some of the most representative strategies adopted for this application are reviewed, paying particular attention to systems based on TiO2, CdS and C3N4.


Assuntos
Formiatos/química , Hidrogênio/química , Catálise , Hidrogenação , Tamanho da Partícula , Processos Fotoquímicos
9.
Molecules ; 24(18)2019 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-31509955

RESUMO

Adsorption of Pd(NH3)42+ in preformed chitosan-graphene oxide (CS-GO) beads and their subsequent reduction with NaBH4 afford well-dispersed, high dispersion (~21%) of uniformly sized Pd nanoparticles (~1.7 nm). The resulting Pd/CS-GO exhibits interesting catalytic activity for hydrogen generation by ammonium formate decomposition. The optimal GO proportion of 7 wt% allows reaching, at 60 °C, a turnover frequency above 2200 h-1-being outstanding among the highest values reported for this process to date. Interestingly, no formation of CO or CH4 was detected. The catalyst did not leach, although it underwent gradual deactivation, probably caused by the increase in the Pd average size that became over 3 nm after three uses. Our results are relevant in the context of efficient on-board hydrogen generation from liquid organic hydrogen carriers in transportation.


Assuntos
Formiatos/química , Grafite/química , Hidrogênio/química , Paládio/química , Adsorção , Catálise , Quitosana/química , Nanopartículas/química , Porosidade
10.
Phys Chem Chem Phys ; 21(38): 21370-21380, 2019 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-31531468

RESUMO

Density functional theory modelling has been used to design Mo and W-based catalysts MoIII(tBu)(CO) and WIII(tBu)(CO) for CO2 hydrogenation and HCOOH dehydrogenation, which are bio-mimics of the active site of formate dehydrogenase. Based on DFT calculations, the molybdenum and tungsten based complexes are good catalysts in the +3 oxidation state for CO2 hydrogenation with free energies of 24.03 and 21.31 kcal mol-1, respectively. Such a low barrier indicates that our newly designed Mo and W-based complexes are very efficient for CO2 hydrogenation or HCOOH dehydrogenation catalysis. Overall, our computational results provide in depth insights that can serve as a great tool for the design and development of new and efficient molybdenum and tungsten based catalysts for CO2 hydrogenation or HCOOH dehydrogenation.


Assuntos
Materiais Biomiméticos/química , Dióxido de Carbono/química , Complexos de Coordenação/química , Formiato Desidrogenases/química , Formiatos/química , Modelos Moleculares , Catálise , Domínio Catalítico , Hidrogenação , Ligantes , Molibdênio/química , Oxirredução , Termodinâmica , Tungstênio/química
11.
Eur J Med Chem ; 182: 111588, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31421630

RESUMO

Intrinsically disordered proteins are an emerging class of proteins without a folded structure and currently disorder-based drug targeting remains a challenge. p53 is the principal regulator of cell division and growth whereas MDM2 consists its main negative regulator. The MDM2-p53 recognition is a dynamic and multistage process that amongst other, employs the dissociation of a transient α-helical N-terminal ''lid'' segment of MDM2 from the proximity of the p53-complementary interface. Several small molecule inhibitors have been reported to inhibit the formation of the p53-MDM2 complex with the vast majority mimicking the p53 residues Phe19, Trp23 and Leu26. Recently, we have described the transit from the 3-point to 4-point pharmacophore model stabilizing this intrinsically disordered N-terminus by increasing the binding affinity by a factor of 3. Therefore, we performed a thorough SAR analysis, including chiral separation of key compound which was evaluated by FP and 2D NMR. Finally, p53-specific anti-cancer activity towards p53-wild-type cancer cells was observed for several representative compounds.


Assuntos
Antineoplásicos/farmacologia , Proteínas Intrinsicamente Desordenadas/antagonistas & inibidores , Proteínas Proto-Oncogênicas c-mdm2/antagonistas & inibidores , Proteína Supressora de Tumor p53/antagonistas & inibidores , Antineoplásicos/síntese química , Antineoplásicos/química , Benzilaminas/síntese química , Benzilaminas/química , Benzilaminas/farmacologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Cianetos/síntese química , Cianetos/química , Cianetos/farmacologia , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Formiatos/síntese química , Formiatos/química , Formiatos/farmacologia , Humanos , Indóis/síntese química , Indóis/química , Indóis/farmacologia , Proteínas Intrinsicamente Desordenadas/química , Proteínas Intrinsicamente Desordenadas/metabolismo , Estrutura Molecular , Proteínas Proto-Oncogênicas c-mdm2/química , Proteínas Proto-Oncogênicas c-mdm2/metabolismo , Relação Estrutura-Atividade , Proteína Supressora de Tumor p53/química , Proteína Supressora de Tumor p53/metabolismo
12.
Australas Phys Eng Sci Med ; 42(3): 811-818, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31410839

RESUMO

The nondestructive dosimetry achieved with electron paramagnetic resonance (EPR) dosimetry facilitates repetitive recording by the same dosimeter to increase the reliability of data. In precedent studies, solid paraffin was needed as a binder material to make the lithium formate monohydrate (LFM) EPR dosimeter stable and nonfragile; however, its use complicates dosimetry. This study proposes a newly designed pure LFM EPR dosimeter created by inserting LFM into a 3D-printed container. Dosimetric characteristics of the LFM EPR dosimeter and container, such as reproducibility, linearity, energy dependence, and angular dependence, were evaluated and verified through a radiation therapy planning system (RTPS). The LFM EPR dosimeters were irradiated using a clinical linear accelerator. The EPR spectra of the dosimeters were acquired using a Bruker EMX EPR spectrometer. Through this study, it was confirmed that there is no tendency in the EPR response of the container based on irradiation dose or radiation energy. The results show that the LFM EPR dosimeters have a highly sensitive dose response with good linearity. The energy dependence across each photon and electron energy range seems to be negligible. Based on these results, LFM powder in a 3D-printed container is a suitable option for dosimetry of radiotherapy. Furthermore, the LFM EPR dosimeter has considerable potential for in vivo dosimetry and small-field dosimetry via additional experiments, owing to its small effective volume and highly sensitive dose response compared with a conventional dosimeter.


Assuntos
Formiatos/química , Impressão Tridimensional , Radiometria , Radioterapia , Espectroscopia de Ressonância de Spin Eletrônica , Elétrons , Fótons , Planejamento da Radioterapia Assistida por Computador , Reprodutibilidade dos Testes
13.
Anal Bioanal Chem ; 411(23): 6091-6100, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31289897

RESUMO

Two 600-bp DNA solutions (DNA600-G and DNA600-T) were developed as certified reference material, NMIJ CRM 6205-a, for the validation of DNA quantification methods. Both DNA600-G and DNA600-T are ideal as "spike-in control" because these materials have artificial nucleic acid sequences. The certified values were determined as the mass concentration of total DNA (whole DNA materials in sample solution regardless of sequence) at 25 °C by formic acid hydrolysis/liquid chromatography-isotope dilution mass spectrometry (LC-IDMS) and inductively coupled plasma-mass spectrometry (ICP-MS) based on the amount of phosphorus. DNAs were synthesized, and plasmids including the synthesized DNAs were cloned into Escherichia coli DH5α. The amplified plasmids were digested with a restriction enzyme and highly purified. Then, the purified DNAs were diluted with water to approximately 1 ng/µL. By using the CRM-validated methods in fields where DNA quantification is required, the reliability of DNA quantification could be improved. Graphical abstract.


Assuntos
DNA/análise , Espectrometria de Massas/métodos , Sequência de Bases , Cromatografia Líquida de Alta Pressão/métodos , Cromatografia Líquida de Alta Pressão/normas , Cromatografia Líquida/métodos , Cromatografia Líquida/normas , DNA/genética , Formiatos/química , Hidrólise , Espectrometria de Massas/normas , Plasmídeos/análise , Plasmídeos/genética , Reação em Cadeia da Polimerase/métodos , Reação em Cadeia da Polimerase/normas , Padrões de Referência
14.
PLoS One ; 14(7): e0218994, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31291279

RESUMO

Unlike most notodontids, Theroa zethus larvae feed on plants that emit copious latex when damaged. To determine how the larvae overcome this defense, we filmed final instars on poinsettia, Euphorbia pulcherrima, then simulated their behaviors and tested how the behaviors individually and combined affect latex exudation. Larvae initially scraped the stem, petiole, or midrib with their mandibles, then secreted acid from their ventral eversible gland (VEG) onto the abraded surface. Scraping facilitated acid penetration by disrupting the waxy cuticle. As the acid softened tissues, the larvae used their mandibles to compress the plant repeatedly, thereby rupturing the latex canals. Scraping, acid application, and compression created withered furrows that greatly diminished latex exudation distal to the furrows where the larvae invariably fed. The VEG in notodontids ordinarily serves to deter predators; when attacked, larvae spray acid aimed directly at the assailant. Using HPLC, we documented that the VEG secretion of T. zethus contains 30% formic acid (6.53M) with small amounts of butyric acid (0.05M). When applied to poinsettia petioles, the acids caused a similar reduction in latex outflow as VEG secretion milked from larvae. VEG acid could disrupt latex canals in part by stimulating the normal acid-growth mechanism employed by plants to loosen walls for cell elongation. Histological examination of cross sections in poinsettia midribs confirmed that cell walls within furrows were often highly distorted as expected if VEG acids weaken walls. Theroa zethus is the only notodontid caterpillar known to use mandibular scraping and VEG acid to disable plant defenses. However, we document that mandibular constriction of petioles occurs also in other notodontids including species that feed on hardwood trees. This capability may represent a pre-adaptation that facilitated the host shift in the Theroa lineage onto latex-bearing plants by enabling larvae to deactivate laticifers with minimal latex contact.


Assuntos
Ácido Butírico/farmacologia , Formiatos/farmacologia , Herbivoria/fisiologia , Larva/fisiologia , Lepidópteros/fisiologia , Adaptação Fisiológica , Animais , Secreções Corporais/química , Secreções Corporais/metabolismo , Ácido Butírico/química , Ácido Butírico/metabolismo , Euphorbia/metabolismo , Euphorbia/parasitologia , Formiatos/química , Formiatos/metabolismo , Látex/biossíntese , Folhas de Planta/metabolismo , Folhas de Planta/parasitologia
15.
J Mater Sci Mater Med ; 30(6): 72, 2019 Jun 11.
Artigo em Inglês | MEDLINE | ID: mdl-31187295

RESUMO

The success of wound healing depends upon the proper growth of vascular system in time in the damaged tissues. Poor blood supply to wounded tissues or tissue engineered grafts leads to the failure of wound healing or rejection of grafts. In present paper, we report the synthesis of novel organosoluble and pro-angiogenic chitosan derivative (CSD) by the reaction of chitosan with 1,3-dimethylbarbituric acid and triethylorthoformate (TEOF). The synthesized material was characterized by FTIR and 13C-NMR to confirm the incorporated functional groups and new covalent connectivities. Biodegradability of the synthesized chitosan derivative was tested in the presence of lysozyme and was found to be comparable with CS. The cytotoxicity and apoptosis effect of new derivative was determined against gastric adenocarcinoma (AGS) cells and was found to be non-toxic. The CSD was found to be soluble in majority of organic solvents. It was blended with polycaprolactone (PCL) to form composite scaffolds. From an ex ovo CAM assay, it was noted that CSD stimulated the angiogenesis.


Assuntos
Quitosana/química , Sistemas de Liberação de Medicamentos , Tecidos Suporte/química , Cicatrização , Adenocarcinoma/tratamento farmacológico , Apoptose , Barbitúricos/química , Materiais Biocompatíveis , Linhagem Celular Tumoral , Membrana Corioalantoide/metabolismo , Formiatos/química , Humanos , Hidrogéis/química , Espectroscopia de Ressonância Magnética , Muramidase/química , Neovascularização Patológica , Neovascularização Fisiológica , Poliésteres/química , Solubilidade , Solventes , Espectroscopia de Infravermelho com Transformada de Fourier , Neoplasias Gástricas/tratamento farmacológico , Engenharia Tecidual/métodos , Viscosidade
16.
J Pharm Biomed Anal ; 174: 495-499, 2019 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-31234040

RESUMO

The study of glycoproteins is a rapidly growing field, which is not surprising considering that approximately 70% of human proteins are glycosylated and that numerous biological functions are associated to the glycosylation. In this work, our interest focused on the heterodimeric human Chorionic Gonadotropin (hCG) glycoprotein that is the specific hormone of the human pregnancy, consisting of an α and a ß subunit, so-called hCGα and hCGß, respectively. This protein possesses a very high structural heterogeneity, essentially due to the presence of 8 glycosylation sites, but also other types of post-translational modifications. In this study, for the first time, the potential of hydrophilic interaction liquid chromatography (HILIC) was investigated to separate the intact hCG isoforms. Three different HILIC stationary phases were tested using an hCG-based drug as standard, a recombinant hCG. For each stationary phase, the effect of the initial mobile phase composition based on ACN/H2O mixture, the slope of the gradient, the content and nature of the acidic additive (formic acid and trifluoroacetic acid (TFA)), and the addition of a volatile salt (ammonium formate) on the retention and the resolution were studied. The best HILIC separation was obtained with the amide column and a mobile phase composed of water/ACN containing 0.1% of TFA. The repeatability in terms of retention times and peak areas was then assessed. Finally, the method was applied to the analysis of a second hCG-based drug obtained from urine of pregnant women. Both drugs gave chromatograms with more than 10 peaks. However, they were significantly different, which demonstrated the potential of HILIC method for hCG isoform fingerprinting.


Assuntos
Gonadotropina Coriônica/química , Cromatografia Líquida/métodos , Gonadotropina Coriônica/urina , Feminino , Formiatos/química , Glicoproteínas/química , Glicosilação , Humanos , Interações Hidrofóbicas e Hidrofílicas , Gravidez , Isoformas de Proteínas/química , Multimerização Proteica , Proteínas Recombinantes , Espectrofotometria Ultravioleta , Ácido Trifluoracético/química
17.
Molecules ; 24(11)2019 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-31185655

RESUMO

The health claims of olive oil represent an important marketing lever in raising the willingness to pay for a product, but world producers of extra virgin olive oil (EVOO) do not take advantage of it because there are still obstacles to their use. Among these, one issue is the lack of an official method for determination of all free and linked forms derived from secoiridoidic structures of hydroxytyrosol and tyrosol. In this study, different acidic hydrolytic procedures for analyzing the linked forms were tested. The best method was validated and then applied to more than 100 EVOOs. The content of oleuropein and ligstroside derivatives in EVOOs was indirectly evaluated comparing the amount of phenols before and after hydrolysis. After acidic hydrolysis, a high content of total tyrosol was found in most of the EVOOs. The use of a suitable corrective factor for the evaluation of hydroxytyrosol allows an accurate determination only using pure tyrosol as a standard. Further knowledge on the concentration of total hydroxytyrosol will assist in forecasting the resistance of oils against aging, its antioxidant potential and to better control its quality over time.


Assuntos
Formiatos/química , Azeite de Oliva/química , Álcool Feniletílico/análogos & derivados , Polifenóis/química , Ácidos Sulfúricos/química , Hidrólise , Itália , Álcool Feniletílico/análise , Álcool Feniletílico/química , Padrões de Referência
18.
J Chromatogr A ; 1603: 102-112, 2019 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-31182305

RESUMO

The robustness of the Peptide Reversed Phase Chromatography (RPC) Column Characterisation Protocol was evaluated using reduced factorial design, to ascertain the degree of control required for parameters including temperature, flow rate, dwell volume, a systematic shift in the gradient, amount of formic acid in the aqueous and organic, pH of the ammonium formate and amount of acetonitrile (%MeCN) in the strong solvent, where a loss of MeCN resulted in an unacceptable variation. Mitigations have been introduced to ensure the integrity of the data to allow RPC columns to be characterised using peptides as probes, with the definitive protocol described. In addition, the instrument and column batch to batch variability were assessed with good reproducibility.


Assuntos
Cromatografia de Fase Reversa/métodos , Peptídeos/isolamento & purificação , Cromatografia Líquida de Alta Pressão/métodos , Formiatos/química , Concentração de Íons de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Análise de Componente Principal , Reprodutibilidade dos Testes , Reologia , Solventes/química , Temperatura
19.
Int J Biol Macromol ; 135: 926-930, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-31170494

RESUMO

The extraordinary left handed conformation of DNA known as Z-DNA has attracted the attention of structural biologists due to its characteristic features such as its possible role in regulation of gene expression and genetic instability. There are number of physical parameters which can induce the conformational transformation of double helical B-DNA to Z-DNA. Among the various physical conditions, right-handed B-DNA can be transformed into left-handed Z-DNA in vitro at high salt concentrations or in vivo under physiological conditions. Herein DNA solubilized in a choline based ionic liquid namely choline formate was found to reduce Ag(I) salt into silver nanoparticles (AgNPs) with the size distribution of 10-20 nm. During the process, the interaction of DNA with the ionic liquid induces alteration in secondary structure of DNA (B-Z transition). The formation of the NPs was confirmed by UV-Vis spectrophotometer and Transmission Electron Microscopic (TEM) measurements, while the formation of Z-DNA was confirmed by circular dichroism (CD) spectroscopic measurements. Upon molecular docking studies, choline-formate was found to present different binding sites for its cation and anion and they promote torsions on DNA structure leading to possible changes in DNA three dimensional structures (B-Z transition).


Assuntos
DNA/química , Líquidos Iônicos/química , Conformação de Ácido Nucleico , Sais/química , Prata/química , Colina/química , Formiatos/química , Nanopartículas Metálicas/química , Simulação de Acoplamento Molecular , Oxirredução , Fatores de Tempo
20.
J Chromatogr A ; 1600: 174-182, 2019 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-31047661

RESUMO

Hydrophilic interaction liquid chromatography (HILIC)/ electrospray ionisation-mass spectrometry (ESI-MS) has gained interest for the analysis of polar analytes in bioanalytical applications in recent years. However, ESI-MS is prone to adduct formation of analytes. In contrast to reversed phase chromatography, small inorganic ions have retention in HILIC, i.e. analytes and inorganic ions may co-elute, which could influence the adduct formation. In the present paper, it was demonstrated that the co-elution of sodium ions or potassium ions and analytes in HILIC/ESI-MS affect the adduct formation and that different concentrations of sodium ions and potassium ions in biological samples could have an impact on the quantitative response of the respective adducts as well as the quantitative response of the protonated adduct. The co-elution also lead to cluster formation of analytes and sodium formate or potassium formate, causing extremely complicated spectra. In analytical applications using HILIC/ESI-MS where internal standards are rarely used or not properly matched, great care needs to be taken to ensure minimal variation of inorganic ion concentration between samples. Moreover, the use of alkali metal ion adducts as quantitative target ions in relative quantitative applications should be made with caution if proper internal standards are not used.


Assuntos
Cromatografia Líquida , Íons/química , Espectrometria de Massas por Ionização por Electrospray , Formiatos/química , Interações Hidrofóbicas e Hidrofílicas
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