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1.
Chemosphere ; 242: 125233, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31896207

RESUMO

Acid/base/oxidant pretreatment influenced subsequent quaternary ammonium epoxide compounds modified carbon (QAE-AC) and hence PFOA and nitrate removal. This work discerned that the most favorable QAE-AC protocol for PFOA removal was achieved when the wood carbon pretreated with HNO3 to adjust the carbon's slurry pH to 4.77, and tailored with the QUAB188. For nitrate removal, the most favorable when the carbon was pretreated with NaOH to raise the carbon's slurry pH to 9.34, and then loaded with the QUAB360. Based on experimentally results and molecular model, we found that pore volume, phenolic groups and the surface charge were the main factors affecting the PFOA removal, while the only factor affecting nitrate removal was surface charge. The QUAB's epoxide functionalities have cross-linked with phenolics along the activated carbon's graphene edge sites. QAE is preferentially reacted with the phenolic in the micropores and mesopores of carbon, and some QAE molecules form new "pore-like structures" outside the pores with the graphene planes or other QAE molecules. This pore-like structure hosted adsorption capacity by the quaternary ammonium. The favorable PFOA adsorption sites were in smaller mesopores via both hydrophobic interaction and electrostatic interaction; and nitrate sorption was occurring in the smaller micropores via anion exchange. Therefore, it can be considered that QAE-AC can simultaneously adsorb PFOA and nitrate in water.


Assuntos
Caprilatos/química , Fluorcarbonetos/química , Modelos Químicos , Nitratos/química , Compostos de Amônio Quaternário/química , Poluentes Químicos da Água/química , Adsorção , Compostos de Amônio/química , Ânions , Carvão Vegetal/química , Compostos de Epóxi , Oxidantes , Água
2.
J Chromatogr A ; 1609: 460519, 2020 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-31521379

RESUMO

In this work, tetraalkylammonium amino acid ionic liquids (TAA-AAILs) were first applied to non-aqueous capillary electrophoresis (NACE) to establish synergistic systems with a conventional chiral selector, native ß-cyclodextrin (ß-CD). Excellent enantioseparations of some dansyl-amino acid (Dns-AA) samples were achieved. A series of comparison experiments and a molecular docking study were performed to validate the synergistic effect of TAA-AAILs and ß-CD in NACE. Several interesting results were observed compared with previously reported chiral ILs-related aqueous CE studies. In particular, the direct enantioselectivity of TAA-AAILs was observed for the first time by using it as sole chiral selector in NACE. This was an encouraging finding because it was the first direct and convincing evidence that AAILs were able to participate in the enantiorecognition process in the conventional chiral selectors-based synergistic systems. The new TAA-AAILs synergistic NACE system was further optimized in terms of alkyl chain length, TAA-AAILs concentration, ß-CD concentration, electrolyte composition and applied voltage, etc. Best enantioseparations of Dns-AAs were obtained when 100 mM ß-CD and 10 mM tetramethylammonium-l-arginine (TMA-l-Arg) were added in an NMF buffer containing 50 mM Tris and 35 mM CA (apparent pH 7.85) under UV detection. The applied voltage was set at 30 kV. The method was then successfully employed for the determination of enantiomeric impurities of a real AA sample. This work proved that the use of chiral ILs as additives in NACE is a promising approach for enantioseparation.


Assuntos
Eletroforese Capilar/métodos , Líquidos Iônicos/química , Arginina/análogos & derivados , Arginina/química , Tampões (Química) , Eletrólitos/química , Concentração de Íons de Hidrogênio , Simulação de Acoplamento Molecular , Compostos de Amônio Quaternário/química , Estereoisomerismo , beta-Ciclodextrinas/química
3.
Anal Bioanal Chem ; 412(3): 669-680, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31834450

RESUMO

A layer-by-layer self-assembled nitrogen-doped graphene/PDDA/gold nanoparticle (NDG/PDDA/GNP) composite was described. Citrate-stabilizing gold nanoparticle colloids (GNPs) were electrostatically adsorbed onto NDG nanosheets using a cationic polyelectrolyte, polydiallyldimethylammonium (PDDA), as the linker, thereby creating a high-performance electrochemical interface. The morphology and chemical composition were characterized by scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, ultraviolet-visible spectroscopy, infrared spectroscopy, and Raman spectroscopy. Analytical application was manifested by electrochemical sensing of uric acid (UA), a biomarker involved with a variety of clinical diseases. The prepared nanocomposite exhibited noticeable electroactivity to uric acid oxidation and can give effective peak separation with ascorbic acid and dopamine. Additionally, the nanocomposite practically averted from other potentially interferents including glucose, urea, and serotonin, thus allowing selective voltammetric detection of UA in the biological matrix. Under the optimal condition, peak currents measured by differential pulse voltammetry were proportional to UA concentrations in the range of 0.5~100 µM (R2 = 0.998), with the detection limit of 53 nM. The NDG/PDDA/GNP nanocomposite as presented herein holds potential for aiding the diagnosis of UA-associated diseases and should be a new opportunity for biochemical analysis and biosensing applications. Graphical abstract.


Assuntos
Técnicas Eletroquímicas/métodos , Ouro/química , Grafite/química , Nanopartículas Metálicas/química , Nitrogênio/química , Polietilenos/química , Compostos de Amônio Quaternário/química , Eletricidade Estática , Ácido Úrico/análise , Limite de Detecção
4.
Carbohydr Polym ; 227: 115296, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31590872

RESUMO

Cutaneous chronic wounds are characterized by an impaired wound healing which may lead to infection. To surmount this problem, a novel quaternary ammonium chitosan nanoparticles (TMC NPs)/chitosan (CS)composite sponge with asymmetric wettability surfaces was successfully prepared. The optimum concentrations of TMC NPs and CS were 0.2 mg/mL and 2.0%, respectively. The incorporated TMC NPs could improve the antibacterial activity of the CS sponge. Asymmetric modification enables the CS sponge to have hydrophobic outer surface and hydrophilic inner surface. The hydrophobic surface of the sponge shows waterproof and anti-adhesion contaminant properties, whereas the hydrophilic surface preserves water-absorbing capability and efficiently inhibits the growth of bacteria. More importantly, in vivo chronic wound healing model evaluation reveals that TMC NPs/CS composite sponge promotes the wound healing and accelerates re-epithelialization and angiogenesis. And in vivo anti-infection test shows the TMC NPs/CS composite sponge could effectively prevent wound infection. These findings demonstrate that TMC NPs/CS composite sponge is a promising dressing material for chronic wounds.


Assuntos
Antibacterianos/administração & dosagem , Bandagens , Quitosana/administração & dosagem , Nanopartículas/administração & dosagem , Compostos de Amônio Quaternário/administração & dosagem , Cicatrização/efeitos dos fármacos , Animais , Antibacterianos/química , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Quitosana/química , Diabetes Mellitus Experimental/tratamento farmacológico , Sistemas de Liberação de Medicamentos , Escherichia coli/efeitos dos fármacos , Escherichia coli/crescimento & desenvolvimento , Masculino , Camundongos , Nanopartículas/química , Compostos de Amônio Quaternário/química , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/crescimento & desenvolvimento
5.
Carbohydr Polym ; 227: 115367, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31590884

RESUMO

In this study, functionalized hydrogel bioadsorbents were produced from gum tragacanth (GT) carbohydrate and quaternary ammonium salt (TMSQA) as a crosslinker. The prepared bioadsorbents were used for the removal of NO3- ions from water through the electrostatic and ion exchange mechanism and antibacterial activity. The effect of quaternary ammonium content on the adsorption capacity was studied. The bioadsorbents were characterized by using FE-SEM, energy dispersive X-Ray (EDX), FT-IR, and TGA techniques. The equilibrium time and the most effective pH value for maximum NO3- removal (20 mg g-1) were 21 min and 7, respectively. A series of isotherms and kinetics models were undertaken and the obtained data were fitted well to the Langmuir isotherm and pseudo-second-order rate kinetic. The thermodynamic study confirmed the suitability of NO3- removal by the as-prepared bioadsorbent at room temperature, and also the negative value of ΔGº = -89.1 kJ mol-1 demonstrating the spontaneous nature of adsorption.


Assuntos
Hidrogéis/química , Nitratos/química , Compostos de Amônio Quaternário/química , Tragacanto/química , Poluentes Químicos da Água/química , Adsorção , Bacillus subtilis/efeitos dos fármacos , Bacillus subtilis/crescimento & desenvolvimento , Escherichia coli/efeitos dos fármacos , Escherichia coli/crescimento & desenvolvimento , Hidrogéis/farmacologia , Concentração de Íons de Hidrogênio , Compostos de Amônio Quaternário/farmacologia , Temperatura Ambiente , Tragacanto/farmacologia , Purificação da Água/métodos
6.
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
7.
Talanta ; 206: 120215, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31514903

RESUMO

This article described the fabrication of novel magnetic carbon nanotube modified with polymeric deep eutectic solvent (M-CNT@PDES) and its application as extractant for the magnetic solid phase extraction (MSPE) of bovine serum albumin (BSA). The physicochemical properties and morphology of M-CNT@PDES were characterized by X-ray diffraction (XRD), vibrating sample magnetometer (VSM), thermo-gravimetric analysis (TGA), zeta potentials, fourier transform infrared spectrometry (FT-IR) and transmission electron microscope (TEM). Afterwards, several parameters such as pH value, initial concentration of BSA, extraction time, ionic strength and extraction temperature were optimized. The results indicated that the modification of PDES significantly improved the extraction performance for BSA, and the maximum extraction capacity was 225.15 mg/g under the optimized conditions. In addition, 0.20 mol/L NaCl-PBS solution was chosen as the appropriate eluent, and favourable elution rate (81.22%) was obtained. Circular dichroism spectroscopy (CD) indicated that the secondary structure of BSA has not changed during extraction and elution. The regenerative experiment and application in real calf serum confirmed the outstanding durability and practical application ability of M-CNT@PDES. All of above verified that the proposed M-CNT@PDES coupled with MSPE method has great application potential for the pre-concentration of biomolecules.


Assuntos
Nanotubos de Carbono/química , Soroalbumina Bovina/análise , Solventes/química , Animais , Bovinos , Eletroforese em Gel de Poliacrilamida , Limite de Detecção , Fenômenos Magnéticos , Compostos de Amônio Quaternário/química , Extração em Fase Sólida/métodos , Xilitol/química
8.
J Pharm Biomed Anal ; 177: 112852, 2020 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-31499432

RESUMO

The effect of insertion of SH and S-protected groups on the binding and mucoadhesion properties of quaternary ammonium-chitosans and their nanoparticulate forms has been investigated by NMR spectroscopy. Diclofenac sodium salt has been assumed as low molecular weight probe to detect the different binding behaviour of polymeric materials; mucin from bovine submaxillary glands was selected as the model protein for differentiating their mucoadhesion. NMR proton selective relaxation rates of the probe molecule were remarkably sensitive to the presence of very low amounts of sulfurated moieties. Impact of supramolecular aggregation in nanostructured species was demonstrated as well as the relevance of S-protection.


Assuntos
Diclofenaco/administração & dosagem , Portadores de Fármacos/química , Membrana Mucosa/metabolismo , Nanopartículas/química , Adesividade , Animais , Bovinos , Quitosana/química , Quitosana/metabolismo , Portadores de Fármacos/metabolismo , Peso Molecular , Mucinas/metabolismo , Nanopartículas/metabolismo , Espectroscopia de Prótons por Ressonância Magnética , Compostos de Amônio Quaternário/química , Compostos de Amônio Quaternário/metabolismo , Enxofre/química
9.
Carbohydr Polym ; 228: 115391, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31635733

RESUMO

Fungal biofilm formation is an emerging problem in a wide range of health-related applications. This study aims to design and synthesize amphiphilic quaternary ammonium chitosans (AQACs) that could bind onto fungal biofilms to kill adherent fungal cells, and establish their structural/fungicidal activity relationships. AQACs with different hydrophobic alkyl chain length (C4, C8, and C12) were synthesized by quaternization of 3-bromopropionic acid with the corresponding tertiary amines, followed by reacting with chitosan using the EDC/NHS chemistry. The new AQACs were soluble in water, yet formed self-aggregates in the solution with different sizes. In antifungal tests against free-floating Candida albicans, shorter alkyl chains (C4) in the AQACs resulted in the most potent fungicidal effect. However, in the treatment of Candida biofilms formed on solid surfaces, AQACs with longer alkyl chains (C8 and C12) were much more effective than their shorter chain counterpart (C4). The effects of alkyl chain self-aggregation on the opposite trend in fungicidal and anti-biofilm activities were discussed. All the AQACs showed excellent cytocompatibility with mammalian cells.


Assuntos
Antifúngicos/química , Biofilmes/efeitos dos fármacos , Quitosana/química , Compostos de Amônio Quaternário/química , Animais , Materiais Biocompatíveis/química , Candida albicans/efeitos dos fármacos , Candida albicans/fisiologia , Linhagem Celular , Conformação Molecular
10.
Talanta ; 206: 120198, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31514838

RESUMO

Due to highly fluorinated and di-anionic characters, it is great challenging to enrich perfluoroalkyl phosphonic acids (PFPAs). According to the unique chemical properties and molecular structure of PFPAs, a monolithic adsorbent using dodecafluoroheptyl acrylate and 4-vinylbenzyltrimethylammonium chloride as mixed functional monomers was synthesized and utilized as the extraction medium of multiple monolithic fibers solid-phase microextraction (MMF-SPME). Results well evidenced that the obtained adsorbent could enrich PFPAs effectively by means of multiple interactions including fluorophilic and anion-exchange interactions. Under the optimized synthesized and extraction conditions, a sensitive approach for the monitoring of trace levels of PFPAs in water and vegetable samples was developed by the combination of MMF-SPME and high performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS). Limits of detection (LODs, S/N = 3) for water and vegetable samples were in the ranges of 0.00011-0.00086 µg/L and 0.0022-0.055 µg/kg, respectively. The introduced method was successfully applied to monitor target PFPAs in lake water, wastewater, pumpkin and cucumber samples. Recoveries at different spiking levels and the relative standard deviations for precision were in the ranges of 80.6-120% and 0.9-12%, respectively. Compared to previously reported approaches, the current method displays some merits such as simple operation, satisfactory sensitivity, low cost and eco-friendliness.


Assuntos
Fluorcarbonetos/análise , Contaminação de Alimentos/análise , Ácidos Fosforosos/análise , Polímeros/química , Poluentes Químicos da Água/análise , Adsorção , Cromatografia Líquida de Alta Pressão , Cucumis sativus/química , Cucurbita/química , Lagos/análise , Limite de Detecção , Compostos de Amônio Quaternário/química , Microextração em Fase Sólida/métodos , Espectrometria de Massas em Tandem , Verduras/química , Águas Residuárias/análise
11.
Chem Commun (Camb) ; 56(5): 762-765, 2020 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-31845680

RESUMO

A multifunctional photodynamic therapy (PDT) nanoplatform, characterized by red-shifted absorption and emission, was fabricated using an UiO-66-based metal-organic framework (MOF), a biscyclometalated iridium(iii) complex, and a pH/ROS-responsive polycationic polymer. Noticeably, this promising nanoplatform exhibited good biocompatibility in the dark and produced abundant ROS upon light irradiation, which could achieve apparent endo/lysosome escape and kill cancer cells effectively.


Assuntos
Resinas Acrílicas/farmacologia , Complexos de Coordenação/farmacologia , Estruturas Metalorgânicas/farmacologia , Nanopartículas/química , Fármacos Fotossensibilizantes/farmacologia , Resinas Acrílicas/química , Resinas Acrílicas/toxicidade , Complexos de Coordenação/química , Complexos de Coordenação/toxicidade , Desenho de Drogas , Células HeLa , Humanos , Irídio/química , Estruturas Metalorgânicas/química , Estruturas Metalorgânicas/toxicidade , Microscopia de Fluorescência/métodos , Fotoquimioterapia/métodos , Fármacos Fotossensibilizantes/química , Fármacos Fotossensibilizantes/toxicidade , Compostos de Amônio Quaternário/química , Compostos de Amônio Quaternário/farmacologia , Compostos de Amônio Quaternário/toxicidade , Espécies Reativas de Oxigênio/metabolismo
12.
Chemosphere ; 240: 124947, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31568943

RESUMO

This work studies the effect of the cation and anion on the biodegradability and inhibition of imidazolium- and choline-based ionic liquids (ILs) using activated sludge. Six commercial ILs, formed by combination of 1-Butyl-3-methylimidazolium (Bmim+) and N,N,N-trimethylethanolammonium (Choline+) cations and chloride (Cl-), acetate (Ac-) and bis(trifluoromethanesulfonyl)imide (NTf2-) anions were evaluated, all representative counter-ions with markedly different toxicity and biodegradability. Inherent and fast biodegradability tests were used to evaluate both the microorganism inhibition and the IL biodegradability. In addition, the ecotoxicological response (EC50) of the ILs was studied using activated sludge and Vibrio fischeri (Microtox® test). Bmim+ and NTf2- can be considered as non-biodegradable, whereas aerobic microorganisms easily degraded Choline+ and Ac-. The biodegradation pattern of each cation/anion is nearly unaffected by counter-ion nature. Moreover, concentrations of CholineNTf2 higher than 50 mg/L caused a partial inhibition on microbial activity, in good concordance with its low EC50 (54 mg/L) measured by respiration inhibition test, which alerts on the negative environmental impact of NTf2-containing ILs on the performance of sewage treatment plants.


Assuntos
Aliivibrio fischeri/efeitos dos fármacos , Biodegradação Ambiental , Colina/análise , Hidrocarbonetos Fluorados/química , Imidazóis/análise , Imidazóis/química , Imidas/química , Compostos de Amônio Quaternário/química , Ecotoxicologia , Líquidos Iônicos/análise , Esgotos/química , Purificação da Água/métodos
13.
Org Biomol Chem ; 17(45): 9778-9791, 2019 12 07.
Artigo em Inglês | MEDLINE | ID: mdl-31701105

RESUMO

This study investigates the synthesis of ß-branched amines and ß-branched quaternary ammonium chloride ionic liquids as novel extractants. The synthesis methodology was tailored to facilitate the reaction scale-up and the use of biorenewable starting materials. The developed process is an overall green, easy and straightforward synthesis of ß-branched amines, and ammonium salts, starting from linear aldehydes. In order to evaluate the potential of the synthesised materials in applications, the rheology, density, thermal stability, chemical stability, phase transitions, and mutual solubility with water of the novel extractants was studied.


Assuntos
Líquidos Iônicos/síntese química , Compostos de Amônio Quaternário/síntese química , Aminas/síntese química , Aminas/química , Interações Hidrofóbicas e Hidrofílicas , Líquidos Iônicos/química , Estrutura Molecular , Compostos de Amônio Quaternário/química , Solubilidade , Água/química
14.
Chem Commun (Camb) ; 55(92): 13880-13883, 2019 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-31675031

RESUMO

Based on the unique property of preferential sequestration of guest molecules, coacervate microdroplets are proposed as enzyme active membrane-free protocells, in which uricase is loaded for efficient detoxification of uric acid in serum.


Assuntos
Urato Oxidase/metabolismo , Ácido Úrico/metabolismo , Células Artificiais/química , Dextranos/química , Corantes Fluorescentes/química , Humanos , Polietilenos/química , Estabilidade Proteica , Compostos de Amônio Quaternário/química , Solubilidade , Ácido Úrico/sangue
15.
Carbohydr Polym ; 226: 115256, 2019 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-31582056

RESUMO

In order to improve the antioxidant and antifungal activity of chitosan, eight chitosan derivatives containing Schiff bases and quaternary ammonium salts were synthesized via an intermediate 6-O-chloroacetyl-2-N,N,N-trimethyl quaternary ammonium salt chitosan. Detailed structural characterization was carried out using FTIR and 1H NMR spectroscopy, and elemental analysis. The antifungal activity against F. oxysporum f. sp. cucumerium, B. cinerea, and F. oxysporum f. sp. niveum was evaluated using a mycelium growth rate test. The results indicated that the chitosan derivatives exhibited enhanced antifungal activity when compared to chitosan, especially at 1.0 mg/mL. 6-[4-(2,3-dihydroxyl-benzimide) pyridine] acetyl-2-N,N,N-trimethyl-chitosan chloride (2.3HBPATC), 6-[4-(2,3,4-trihydroxyl-benzimide) pyridine] acetyl-2-N,N,N-trimethyl-chitosan chloride (2.3.4HBPATC), 6-[4-(2-fluorine-benzimide) pyridine] acetyl-2-N,N,N-trimethyl-chitosan chloride (FBPATC), 6-[4-(2-chlorine-benzimide) pyridine] acetyl-2-N,N,N-trimethyl-chitosan chloride (CBPATC), 6-[4-(2-bromine-benzimide) pyridine] acetyl-2-N,N,N-trimethyl-chitosan chloride (BBPATC), and 6-[4-(2-hydroxyl-4-chlorine-benzimide) pyridine] acetyl-2-N,N,N-trimethyl-chitosan chloride (HCBPATC) showed inhibitory indices >90.0% at 1.0 mg/mL against F. oxysporum f. sp. cucumerium and B. cinerea. Furthermore, the chitosan derivatives showed stronger antioxidant activity than chitosan, especially 2.3HBPATC and 2.3.4HBPATC with inhibitory indices of 100.0% at 1.6 mg/mL against DPPH and superoxide radicals. Based on these data, it is reasonable to suggest that the introduction of phenolic hydroxyl and halogen groups enhances the antifungal and antioxidant activity of chitosan.


Assuntos
Antifúngicos , Antioxidantes , Botrytis/efeitos dos fármacos , Quitosana/análogos & derivados , Fusarium/efeitos dos fármacos , Antifúngicos/síntese química , Antifúngicos/química , Antifúngicos/farmacologia , Antioxidantes/síntese química , Antioxidantes/química , Antioxidantes/farmacologia , Compostos de Amônio Quaternário/química , Bases de Schiff/química , Relação Estrutura-Atividade
16.
Chem Pharm Bull (Tokyo) ; 67(10): 1042-1045, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31582624

RESUMO

Biaryls are important compounds with widespread applications in many fields. Tetramethylammonium fluoride tetrahydrate was found to promote the biaryl coupling of aryl iodides bearing electron-withdrawing substituents with unactivated arenes. The reaction takes place at temperatures between 100 and 150°C and can be applied to a wide range of aromatic and heteroaromatic rings, affording the products in moderate to high yields. The reaction does not require strong bases or expensive additives that are employed in the existing methods and can be conducted in air and moisture without any precautions.


Assuntos
Hidrocarbonetos Aromáticos/química , Hidrocarbonetos Iodados/química , Compostos de Amônio Quaternário/química , Ar , Estrutura Molecular , Temperatura Ambiente , Água/química
18.
Molecules ; 24(20)2019 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-31614959

RESUMO

It was recently shown that tetramethylammonium chloride presented negative deviations to ideality when mixed with tetraethylammonium chloride or tetrapropylammonium chloride, leading to a strong decrease of the melting points of these salt mixtures, in a behavior akin to that observed in the formation of deep eutectic solvents. To better rationalize this unexpected melting point depression between two structurally similar compounds devoid of dominant hydrogen bonding capability, new solid-liquid equilibria data for tetramethylammonium-based systems were measured and analyzed in this work. Molecular dynamics was used to show that the strong negative deviations from ideality presented by these systems arise from a synergetic share of the chloride ions. A transfer of chloride ions seems to occur from the bigger cation in the mixture (which possesses a more disperse charge) to the smaller cation (tetramethylammonium), resembling the formation of metal-chloride complexes in type I deep eutectic solvents. This rearrangement of the charged species leads to an energetic stabilization of both components in the mixture, inducing the negative deviations to the ideality observed. The conclusions presented herein emphasize the often-neglected contribution of charge delocalization in deep eutectic solvents formation and its applicability toward the design of new ionic liquid mixtures.


Assuntos
Complexos de Coordenação/química , Líquidos Iônicos/química , Solventes/química , Cátions/química , Cloretos/química , Ligações de Hidrogênio , Simulação de Dinâmica Molecular , Estrutura Molecular , Compostos de Amônio Quaternário/química , Ureia/química
19.
Int J Nanomedicine ; 14: 6575-6585, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31616144

RESUMO

Background and purpose: In a past study, we developed and optimized a novel cationic PEGylated niosome containing anticancer drugs (doxorubicin or quercetin) and siRNA. This study intended to evaluate the anti-tumor effects of the combination therapy to target both the proteins and genes responsible for the development of gastric cancer. CDC20, known as an oncogene, is a good potential therapeutic candidate for gastric cancer. Methods: In order to increase the loading capacity of siRNA and achieve appropriate physical properties, we optimized the cationic PEGylated niosome in terms of the amount of the cationic lipids. Drugs (doxorubicin and quercetin) and CDC20siRNA were loaded into the co-delivery system, and physical characteristics, thermosensitive controlled-release, gene silencing efficiency, and apoptosis rate were determined. Results: The results showed that the designed co-delivery system for the drugs and gene silencer had an appropriate size and a high positive charge for loading siRNA, and also showed a thermosensitive drug release behavior, which successfully silenced the CDC20 expression when compared with the single delivery of siRNA or the drug. Moreover, the co-delivery of drugs and CDC20siRNA exhibited a highly inhibitory property for the cell growth of gastric cancer cells. Conclusion: It seems that the novel cationic PEGylated niosomes co-loaded with anticancer drug and CDC20siRNA has a promising application for the treatment of gastric cancer.


Assuntos
Proteínas Cdc20/metabolismo , Doxorrubicina/uso terapêutico , Polietilenoglicóis/química , Quercetina/uso terapêutico , RNA Interferente Pequeno/metabolismo , Neoplasias Gástricas/tratamento farmacológico , Neoplasias Gástricas/metabolismo , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Apoptose/efeitos dos fármacos , Cátions , Proteínas Cdc20/genética , Linhagem Celular Tumoral , Doxorrubicina/farmacologia , Liberação Controlada de Fármacos , Endocitose , Ácidos Graxos Monoinsaturados/química , Inativação Gênica/efeitos dos fármacos , Humanos , Lipossomos , Tamanho da Partícula , Compostos de Amônio Quaternário/química , Quercetina/farmacologia , RNA Interferente Pequeno/genética , Eletricidade Estática , Temperatura Ambiente
20.
Chem Commun (Camb) ; 55(92): 13808-13811, 2019 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-31613284

RESUMO

Precise spatiotemporal control of singlet oxygen generation is of immense importance considering its involvement in photodynamic therapy. In this work, we present a rational design for an endoperoxide which is highly stable at ambient temperatures yet, can rapidly be converted into a highly labile endoperoxide, thus releasing the "stored" singlet oxygen on demand. The "off-on" chemical switching from the stable to the labile form is accomplished by the reaction with fluoride ions. The potential utility of controlled singlet oxygen release was demonstrated in cell cultures.


Assuntos
Materiais Biocompatíveis/química , Oxigênio Singlete/química , Materiais Biocompatíveis/farmacologia , Sobrevivência Celular/efeitos dos fármacos , Fluoretos/química , Humanos , Células MCF-7 , Microscopia Confocal , Naftalenos/química , Compostos de Amônio Quaternário/química , Oxigênio Singlete/toxicidade , Temperatura Ambiente
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