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1.
Food Chem ; 398: 133871, 2023 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-35964562

RESUMO

Natural deep eutectic solvents (NADES) coupled with ultrasound assisted extraction (UAE) was evaluated as extraction techniques for bioactive compounds from apple pomace. Seven natural deep eutectic solvents (NADES) with different molar ratios were explored as green extraction solvents to evaluate extraction efficiency in terms of total flavonoid content (TFC), total phenolic content (TPC), lipid peroxidation inhibition (LBI) and antioxidant potential. The solvents which performed better than conventional solvent were DES1 (Choline chloride: glycerol (1:2)), DES2 (Choline chloride: lactic acid (1:3)) and DES5 ((Choline chloride: citric acid (1:1)). These solvents were further evaluated for optimisation of processing parameters in UAE-DES. The maximum TPC value was achieved using sonication time 40 min, water 30 %, solid/liquid ratio 1:30, temperature 40 °C, acoustic intensity 83.2 W/cm2 and duty cycle 75 %. HPLC of optimised extract was utilised for quantification of polyphenol compounds showing quercetin as main compound followed by chlorogenic acid, gallic acid, phloretin, phloridizin and rutin.


Assuntos
Malus , Colina , Solventes Eutéticos Profundos , Fenóis , Extratos Vegetais , Solventes
2.
Food Chem ; 398: 133935, 2023 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-35986995

RESUMO

Nitrite is a widely used food additive that has been shown to be carcinogenic and can cause health damage when consumed in excess. Therefore, developing a detection method is in demand. Here, we prepared a novel Fe-doped carbon dots (Fe-CDs) using metallic deep eutectic solvent (MDES) which showed high sensitivity and selectivity. Besides, it also showed excellent pH-dependent luminescence characteristics, which proved the feasibility as a pH sensor. Under the optimal conditions, the detection linear of nitrite ranged from 0.2 to 80 µM, and the detection limit was 50 nM. The recovery rate was between 98.8 % and 104.1 % in food and water samples. For pH monitoring, its fluorescence intensity was linearly correlated in the pH range from 2 to 7, accompanying a unique differential solution color change of colorless-yellow-green. Therefore, it can be used as an excellent fluorescent probe for detection of nitrite and pH in food and water environment.


Assuntos
Corantes Fluorescentes , Pontos Quânticos , Carbono , Solventes Eutéticos Profundos , Concentração de Íons de Hidrogênio , Nitritos , Solventes , Água
3.
Food Chem ; 399: 133949, 2023 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-35998496

RESUMO

This study demonstrated that solvent-free gas bubbling system enhanced production efficiency of pyridoxine monolaurate in the esterification catalyzed by immobilized Candida antarctica lipase B (Lipozyme 435). Volumetric productivity in solvent-free gas bubbling system (41.24 mmol/L/h) was 3.7 and 2.1-fold higher than those in conventional organic solvent system (11.10 mmol/L/h) and solvent-free system (19.86 mmol/L/h) using magnetic stirring, respectively. Among the three bioreactor systems, solvent-free gas bubbling system provided the best reusability of the lipase retaining 94.45 % of initial activity for six batch reactions. In the bioreactor system, 5-O-lauroyl-pyridoxine was regioselectively produced with maximum production of 371.17 mmol/L at 70 °C and 0.10 of substrate molar ratio ([pyridoxine]/[lauric acid]) for 9 h. Pyridoxine monolaurate exhibited interfacial activity at oil-water interfaces, suggesting it had emulsifying properties. Pyridoxine monolaurate is expected to be applied as a multi-functional emulsifier with nutritional values to replace both small molecule emulsifiers and pyridoxine hydrochloride in fortified beverages.


Assuntos
Enzimas Imobilizadas , Piridoxina , Reatores Biológicos , Catálise , Enzimas Imobilizadas/química , Esterificação , Lipase/metabolismo , Solventes/química
4.
Food Chem ; 399: 133901, 2023 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-36001927

RESUMO

In this study, a novel supramolecular solvent based on surface-active ionic liquid was prepared and used as an extraction solvent for dispersive liquid-liquid microextraction of four triazine herbicides in tea samples. The formation mechanism, microstructure and physicochemical properties of supramolecular solvent were studied. Some parameters, including the molar ratio of surface-active ionic liquid to tetrahydrofuran, volume of supramolecular solvent, vortex time, pH of sample solution, type and amount of salt, were investigated and optimized. The good linearities (r > 0.9990) for the analytes were obtained. The limits of detection and quantification for triazine herbicides were in the range of 1.7-2.1 µg kg-1 and 5.6-7.1 µg kg-1, respectively. The spiked recoveries were 80.0-119.9 %. The supramolecular solvent prepared in this study has the advantages of simple preparation process, low viscosity and good dispersibility. It can be used for the extraction and enrichment of trace triazine herbicides in tea samples.


Assuntos
Herbicidas , Líquidos Iônicos , Microextração em Fase Líquida , Cromatografia Líquida de Alta Pressão , Herbicidas/análise , Líquidos Iônicos/química , Limite de Detecção , Solventes/química , Chá , Triazinas/análise
5.
Food Chem ; 399: 133929, 2023 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-36055067

RESUMO

The main purpose of this research article is to develop a vortex-assisted switchable hydrophilicity solvent liquid phase microextraction (VA-SHS-LPME) for the selective and efficient extraction of trace vanillin in food samples. Four switchable hydrophilicity solvents (SHSs) were prepared and tested for the extraction of vanillin. The obtained extract phase after phase separation was analyzed by UV-vis spectrophotometry. The extraction parameters including pH, vortex time, NaOH volume, and SHS volume were optimized using central composite design based on response surface methodology. Under optimized conditions, the linear range (0.2-400 ng mL-1 with r2 = 0.9985), limit of detection (0.06 ng mL-1), limit of quantitation (2.0 ng mL-1), extraction recovery (97 ± 4 %) and enhancement factor (220) were obtained. Also, relative standard deviations were less than 2.1 % indicating good precision. The VA-SHS-LPME procedure showed some advantages including good extraction, low consumption of chemical and low matrix effect. Finally, the VA-SHS-LPME procedure was applied for the determination of vanillin in food samples, and acceptable recoveries (91 ± 3-99 ± 3 %) were obtained.


Assuntos
Microextração em Fase Líquida , Benzaldeídos , Interações Hidrofóbicas e Hidrofílicas , Limite de Detecção , Microextração em Fase Líquida/métodos , Solventes , Espectrofotometria
6.
Food Chem ; 399: 133941, 2023 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-36007445

RESUMO

A deep eutectic system (DESys) is formed when a hydrogen bond acceptor (HBA) is processed with polysaccharide (hydrogen bond donor, HBD) containing plant substance in water to dissolve, extract, and recover the polysaccharide directly, instead of using a traditional deep eutectic solvent (DES). The extraction efficiency is enhanced by the direct formation of the DESys, in a mechanochemical extraction (MCE) system. Key factors affecting the extraction efficiency were systematically studied and optimized. The effects of the DESys on the structure and physicochemical properties of polysaccharides were studied by several analytical techniques. The findings demonstrated that the direct DESys formation extraction efficiency was superior than that of traditional extraction methods while retaining physicochemical properties of polysaccharides. Moreover, the composition of polysaccharides extracted with this method is different from that obtained by conventional methods. The recovery and purification process of polysaccharides is simplified by eliminating the need for an additional HBD.


Assuntos
Solventes Eutéticos Profundos , Extratos Vegetais , Polissacarídeos , Ligação de Hidrogênio , Extratos Vegetais/química , Plantas , Solventes/química
7.
Biotechnol Bioeng ; 119(3): 845-856, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-34928500

RESUMO

Biocatalysis in high-concentration organic solvents (OSs) offers many advantages, but realizing this process remains a huge challenge. An R-selective ω-amine transaminase variant (AcATAM2 ) exhibited high activity toward 50 g/L pro-sitagliptin ketone 1-[1-piperidinyl]-4-[2,4,5-trifluorophenyl]-1,3-butanedione (PTfpB). However, AcATAM2 displayed unsatisfactory organic-cosolvent resistance against high-concentration dimethyl sulfoxide (DMSO), which is required to enhance the solubility of the hydrophobic substrate PTfpB. Located in the substrate-binding tunnel, enzyme gates are structural elements that undergo reversible conformational transitions, thus affecting the accessibility of the binding pocket to solvent molecules. Depending on the conformation of the enzyme gates, one can define an open or closed conformation on which the enzyme activity in OSs may depend. To enhance the DMSO resistance of AcATAM2 , we identified the beneficial residues at the "enzyme gate" region via computational analysis, alanine scanning, and site-saturation mutagenesis. Two beneficial variants, namely, AcATAM2 F56D and AcATAM2 F56V , not only displayed improved enzyme activity but also exhibited enhanced DMSO resistance (the half-life value increased from 25.71 to 42.49 h under 60% DMSO). Molecular dynamic simulations revealed that the increase in DMSO resistance was mainly caused by the decrease in the number of DMSO molecules in the substrate-binding pocket. Moreover, in the kilogram-scale experiment, the conversion of 80 g/L substrate was increased from 50% (AcATAM2 ) to 85% (M2F56D in 40% DMSO) with a high e.e. of >99% within 24 h.


Assuntos
Dimetil Sulfóxido , Simulação de Dinâmica Molecular , Biocatálise , Dimetil Sulfóxido/química , Solventes/química , Transaminases/genética
8.
J Mol Model ; 28(10): 297, 2022 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-36066691

RESUMO

In this study, the effect of non-covalent interactions on the para-aminosalicylic acid complex is explored using density functional theory (DFT) in the gas phase and the solution. Our findings exhibit that the achieved binding energies considerably change on going from the gas phase to the solution. Based on the obtained results, the absolute value of the binding energy of the complex in the polar solvents is lower than the non-polar ones while in the gas phase it is higher than the solution. The atoms in molecules (AIM) and the natural bond orbital (NBO) analyses are applied to estimate the topological properties and the charge transfer during complexation, respectively. The results indicate that the presence of the cation-π interaction increases the strength of the intramolecular hydrogen bond in the studied complex. Finally, the various electronic descriptors such as energy gap, hardness, softness, and electronic chemical potential are investigated to gain further insight into these interactions. According to the achieved results, the high energy gap of the complex in the water solvent indicates high chemical stability and low reactivity compared to the others. On the other hand, the most reactive as well as the softest complex belongs to the gas phase.


Assuntos
Ácido Aminossalicílico , Tuberculose , Teoria da Densidade Funcional , Humanos , Modelos Moleculares , Teoria Quântica , Solventes/química
9.
J Mol Model ; 28(10): 302, 2022 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-36066774

RESUMO

In the present research, the cation-π interactions in acetaminophen-M complexes (M = Mn+, Fe2+, Co+, Ni2+, and Cu+) are investigated using density functional theory (DFT/ωB97XD) in the gas phase and solution. The results show that the absolute values of energy are reduced in going from the gas phase to the solution. Based on the obtained data, the complexes in water are the most stable. The natural bond orbital (NBO) and the atoms in molecules (AIM) analyses are also applied to achieve more details about the nature of interactions. These results are useful for understanding the role of the drug-receptor interactions in the complexes. According to AIM outcomes, the cation-π interactions are the closed-shell and may indicate the partially covalent nature in the complexes. A comprehensive analysis is also performed on the conceptual DFT parameters of the complexes to evaluate their electronic properties. Our findings show increasing the stability and decreasing the reactivity of the complexes in the solution phase with respect to the gas phase. These interactions are ubiquitous in biological systems, and their importance in theoretical models led us to study such important interactions. The results of this study may be useful for the design and synthesis of a variety of supramolecular complexes with the desired properties.


Assuntos
Acetaminofen , Modelos Teóricos , Cátions , Eletrônica , Solventes
10.
Environ Monit Assess ; 194(10): 737, 2022 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-36068415

RESUMO

Solvents, components of pesticide emulsifiable concentrates (ECs), emit quantities of volatile organic compounds (VOCs) into the atmosphere. In the air, their active involvement in oxidative chemical reactions with oxidants exposed to ultraviolet solar radiation can result in the formation of ozone. The quantitative assessment of VOC emissions from agricultural pesticide applications remains hampered by many factors, especially the volatility coefficient of solvents in pesticides. Therefore, this study identified solvents in 20 widely used pesticide products in China. The volatility coefficients of the solvents were investigated based on a spraying test to evaluate VOC emissions from agricultural pesticide applications and their ozone formation potential (OFP). The results suggest that VOC emissions from agricultural pesticide applications amount to 0.60 Mt in 2017, with insecticides, fungicides, and herbicides contributing 0.39 Mt, 0.12 Mt, and 0.09 Mt of VOCs, respectively. Since VOC emission and maximum incremental reactivity (MIR) led to an OFP value (2.1 g ozone/g product) for insecticides, a primary consideration should be to decrease use of solvents with high volatility coefficients and large MIR values in insecticide products. This work could provide valuable insights regarding response options to reduce VOC emissions and ozone formation.


Assuntos
Poluentes Atmosféricos , Inseticidas , Ozônio , Praguicidas , Compostos Orgânicos Voláteis , Poluentes Atmosféricos/análise , China , Monitoramento Ambiental/métodos , Ozônio/análise , Solventes , Emissões de Veículos/análise , Compostos Orgânicos Voláteis/análise
11.
J Chem Phys ; 157(8): 080901, 2022 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-36050013

RESUMO

In the Stokes-Einstein picture, diffusion of a Brownian particle or a molecule in a liquid solvent is caused by unbalanced fluctuations of osmotic forces on different sides of the particle. When the particle carries a charge or a higher multipolar moment, this picture is amended by fluctuations of electrostatic forces producing dielectric friction. Dielectric friction slows down both the translational and rotational diffusion. While this picture is well established and is physically sound, standard theories grossly overestimate the magnitude of dielectric friction for small dipolar solutes and larger colloidal particles, such as proteins. Motivated by recent simulation studies, this Perspective discusses the interplay between osmotic (van der Waals) and electrostatic forces in promoting molecular and colloidal diffusion. Much can be learned about microscopic friction mechanisms from statistical and dynamical correlations between osmotic and electrostatic forces.


Assuntos
Eletricidade Estática , Simulação por Computador , Difusão , Soluções , Solventes
12.
J Chem Phys ; 157(8): 084502, 2022 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-36050016

RESUMO

In a recent study [J. Phys. Chem. B 126, 4584-4598 (2022)], we have used infrared spectroscopy to investigate the solvation and dynamics of solitary water in ionic liquids and dipolar solvents. Complex shapes observed for water OH-stretching bands, common to all high-polarity solvents, were assigned to water in several solvation states. In the present study, classical molecular dynamics simulations of a single water molecule in four ionic liquids and three dipolar solvents were used to test and refine this interpretation. Consistent with past assignments, simulations show solitary water usually donates two hydrogen bonds to distinct solvent molecules. Such symmetrically solvated water produces the primary pair of peaks identified in the OH spectra of water in nearly all solvents. We had further proposed that additional features flanking this main peak are due to asymmetric solvation states, states in which only one OH group makes a hydrogen bond to solvent. Such states were found in significant concentrations in all of the systems simulated. Simulations of the OH stretching spectra using a semiclassical description and the vibrational map developed by Auer and Skinner [J. Chem. Phys. 128, 224511-224512 (2008)] provided semi-quantitative agreement with experiment. Analysis of species-specific spectra confirmed assignment of the additional features in the experimental spectra to asymmetrically solvated water. The simulations also showed that rapid water motions cause a marked motional narrowing compared with the inhomogeneous limit. This narrowing is largely responsible for making the additional features due to minority solvation states manifest in the spectra.


Assuntos
Líquidos Iônicos , Ligação de Hidrogênio , Líquidos Iônicos/química , Solventes/química , Espectrofotometria Infravermelho/métodos , Água/química
13.
AAPS PharmSciTech ; 23(7): 252, 2022 Sep 08.
Artigo em Inglês | MEDLINE | ID: mdl-36076112

RESUMO

Deep eutectic solvents (DESs) based on choline chloride (C) and L-(+)-tartaric acid diethyl ester (L) were prepared and used in transdermal drug delivery system (TDDS). The internal chemistry structure including the formation and changes of hydrogen bonds of choline chloride and L-(+)-tartaric acid diethyl ester DES was characterized via attenuated total reflection Fourier transform infrared (ATR-FTIR) and 1H nuclear magnetic resonance (1H NMR) spectroscopy. The stoichiometric ratio of choline chloride to L-(+)-tartaric acid diethyl ester as well as water content affected the viscosity, glass transition temperature (Tg), and drug solubility of the DES. The viscosity and glass transition temperature of the DES (CL14) prepared at the ratio of 1:4 of choline chloride to L-(+)-tartaric acid diethyl ester were 1.19 Pa·s and - 44.01°C, respectively, and decreased to 0.10 Pa·s and - 55.31°C when 10% water (CL1410) was added. Taking diclofenac diethylamine (DDEA), the nonsteroidal anti-inflammatory drug as model, drug solubility was as high as 60 mg/ml and 250 mg/ml in CL14 and CL1410, respectively. The cumulative amount of DDEA was 4.63 ± 2.67 µg/cm2 and 15.27 ± 4.63 µg/cm2 for CL14 and CL1410, respectively, at 8 h. The mechanism of percutaneous permeability by the DES may be the disturbance of stratum corneum (SC) lipids as well as changes in the protein conformations. CL14 and CL1410 were also verified as low-cytotoxic and nonirritant. Therefore, the DESs studied are promising to be used in drug solubilization enhancement and transdermal drug delivery system.


Assuntos
Colina , Solventes Eutéticos Profundos , Colina/química , Preparações Farmacêuticas/química , Solventes/química , Tartaratos , Água/química
14.
Oxid Med Cell Longev ; 2022: 8368717, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36082083

RESUMO

Nowadays, the environmentally friendly approach to everyday life routines including body supplementation with pharma-, nutraceuticals and dietary supplements gains popularity. This trend is implemented in pharmaceutical as well as cosmetic and antiageing industries by adopting a newly developed green chemistry approach. Following this trend, a new type of solvents has been created, called Natural Deep Eutectic Solvents (NADES), which are produced by plant primary metabolites. These solvents are becoming a much better alternative to the already established organic solvents like ethanol and ionic liquids by being nontoxic, biodegradable, and easy to make. An interesting fact about NADES is that they enhance the biological activities of the extracted biological compounds. Here, we present our results that investigate the potential antiageing effect of CiAPD14 as a NADES solvent and three plant extracts with it. The tested NADES extracts are from propolis and two well-known medicinal plants-Sideritis scardica and Plantago major. Together with the solvent, their antiageing properties have been tested during the chronological lifespan of four Saccharomyces cerevisiae yeast strains-a wild type and three chromatin mutants. The chromatin mutants have been previously proven to exhibit characteristics of premature ageing. Our results demonstrate the potential antiageing activity of these NADES extracts, which was exhibited through their ability to confer the premature ageing phenotypes in the mutant cells by ameliorating their cellular growth and cell cycle, as well as by influencing the activity of some stress-responsive genes. Moreover, we have classified their antiageing activity concerning the strength of the observed bioactivities.


Assuntos
Plantago , Própole , Sideritis , Cromatina , Longevidade , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Própole/farmacologia , Saccharomyces cerevisiae , Solventes/química
15.
Sci Rep ; 12(1): 15634, 2022 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-36115867

RESUMO

This paper threw some light on the behavior of Sodium N,N-Dimethyldithiocarbamate as an electrolyte. The effect of solvents on the conductance of this salt would be discussed via measurements of Λo, ao and KA, since it can be assumed that the different solvents have a little chance to impose great variations on the solvation processes. The conductance method was chosen as a tool to illustrate the electrolyte-solvent interactions. Fuoss-Onsager equation would be tested using Sodium Dimethyldithiocarbamate in presence of dimethylformamide solvent at different temperatures. The conductance of dilute solutions of Sodium N,N-Dimethyldithiocarbamate is measured in Dimethylformamide, at different temperatures (25, 30, 35 and 40 °C). Accurate values of Λo were obtained by applying the (Fuoss-Kraus-Shedlovsky) equation. Finally, the (Fuoss-Onsager) equation was solved to give the correct values of the constants Λo, J, KA and a° (the closest distance of approach) for Sodium N,N-Dimethyldithiocarbamate salt in Dimethylformamide solvent. Λo and a° (solvation) increase with increasing temperatures. Thermodynamic parameters (∆G°, ∆H°, ∆S° and ∆Es) of Sodium N,N-Dimethyldithiocarbamate in Dimethylformamide were calculated from conductance measurements, the activation energy (∆Es), the enthalpy change (heat of association) (∆H°) and the entropy change (∆S°) are positive, however The free energy change (∆G°) values was negative for Sodium N,N-Dimethyl dithiocarbamate in DMF systems studied with increasing the temperature.


Assuntos
Dimetilformamida , Sódio , Dimetilditiocarbamato , Condutividade Elétrica , Eletrólitos , Íons , Solventes , Temperatura , Termodinâmica
16.
Molecules ; 27(17)2022 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-36080354

RESUMO

Since its first use as a drug delivery system, mesoporous silica has proven to be a surprisingly efficient vehicle due to its porous structure. Unfortunately, most synthesis methods are based on using large amounts of surfactants, which are then removed by solvent extraction or heat treatment, leading to an undesired environmental impact because of the generated by-products. Hence, in the present study, we followed the synthesis of a silica material with a wormhole-like pore arrangement, using two FDA-approved substances as templates, namely Tween-20 and starch. As far as we know, it is the first study using the Tween-20/starch combo as a template for mesoporous silica synthesis. Furthermore, we investigated whether the obtained material using this novel synthesis had any potential in using it as a DDS. The material was further analyzed by XRD, TEM, FT-IR, N2 adsorption/desorption, and DLS to investigate its physicochemical features. Vancomycin was selected as the active molecule based on the extensive research engaged towards improving its bioavailability for oral delivery. The drug was loaded onto the material by using three different approaches, assuming its full retention in the final system. Thermal analysis confirmed the successful loading of vancomycin by all means, and pore volume significantly decreased upon loading, especially in the case of the vacuum-assisted method. All methods showed a slower release rate compared to the same amount of the pure drug. Loadings by physical mixing and solvent evaporation released the whole amount of the drug in 140 min, and the material loaded by the vacuum-assisted method released only 68.2% over the same period of time, leading us to conclude that vancomycin was adsorbed deeper inside the pores. The kinetic release of the three systems followed the Higuchi model for the samples loaded by physical mixing and vacuum-assisted procedures, while the solvent evaporation loading method was in compliance with the first-order model.


Assuntos
Dióxido de Silício , Vancomicina , Adsorção , Portadores de Fármacos/química , Polissorbatos , Porosidade , Dióxido de Silício/química , Solubilidade , Solventes , Espectroscopia de Infravermelho com Transformada de Fourier , Amido
17.
Molecules ; 27(17)2022 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-36080376

RESUMO

Reducing the use of solvents is an important aim of green chemistry. Using micelles self-assembled from amphiphilic molecules dispersed in water (considered a green solvent) has facilitated reactions of organic compounds. When performing reactions in micelles, the hydrophobic effect can considerably accelerate apparent reaction rates, as well as enhance selectivity. Here, we review micellar reaction media and their potential role in sustainable chemical production. The focus of this review is applications of engineered amphiphilic systems for reactions (surface-active ionic liquids, designer surfactants, and block copolymers) as reaction media. Micelles are a versatile platform for performing a large array of organic chemistries using water as the bulk solvent. Building on this foundation, synthetic sequences combining several reaction steps in one pot have been developed. Telescoping multiple reactions can reduce solvent waste by limiting the volume of solvents, as well as eliminating purification processes. Thus, in particular, we review recent advances in "one-pot" multistep reactions achieved using micellar reaction media with potential applications in medicinal chemistry and agrochemistry. Photocatalyzed reactions in micellar reaction media are also discussed. In addition to the use of micelles, we emphasize the process (steps to isolate the product and reuse the catalyst).


Assuntos
Micelas , Polímeros , Interações Hidrofóbicas e Hidrofílicas , Polímeros/química , Solventes , Água/química
18.
Molecules ; 27(17)2022 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-36080396

RESUMO

The Met80Ala variant of yeast cytochrome c is known to possess electrocatalytic properties that are absent in the wild type form and that make it a promising candidate for biocatalysis and biosensing. The versatility of an enzyme is enhanced by the stability in mixed aqueous/organic solvents that would allow poorly water-soluble substrates to be targeted. In this work, we have evaluated the effect of dimethylsulfoxide (DMSO) on the functionality of the Met80Ala cytochrome c mutant, by investigating the thermodynamics and kinetics of electron transfer in mixed water/DMSO solutions up to 50% DMSO v/v. In parallel, we have monitored spectroscopically the retention of the main structural features in the same medium, focusing on both the overall protein structure and the heme center. We found that the organic solvent exerts only minor effects on the redox and structural properties of the mutant mostly as a result of the modification of the dielectric constant of the solvent. This would warrant proper functionality of this variant also under these potentially hostile experimental conditions, that differ from the physiological milieu of cytochrome c.


Assuntos
Citocromos c , Dimetil Sulfóxido , Citocromos c/metabolismo , Dimetil Sulfóxido/química , Cinética , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Solventes , Termodinâmica , Água
19.
Molecules ; 27(17)2022 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-36080470

RESUMO

Besides their extremely useful properties as solvent, ionic liquids (ILs) are now considered to be highly instructive tools for enhancing the rates of chemical reactions. The ionic nature of the IL anion and cation seems to be the origin of this fascinating function of ILs as organocatalyst/promoter through their strong Coulombic forces on other ionic species in the reaction and also through the formation of hydrogen bonds with various functional groups in substrates. It is now possible to tailor-make ILs for specific purposes as solvent/promoters in a variety of situations by carefully monitoring these interactions. Despite the enormous potentiality, it seems that the application of ILs as organocatalysts/promoters for chemical reactions have not been fully achieved so far. Herein, we review recent developments of ILs for promoting the nucleophilic reactions, focusing on fluorination. Various aspects of the processes, such as organocatalytic capability, reaction mechanisms and salt effects, are discussed.


Assuntos
Líquidos Iônicos , Ânions/química , Halogenação , Ligação de Hidrogênio , Líquidos Iônicos/química , Solventes/química
20.
Molecules ; 27(17)2022 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-36080482

RESUMO

In this study, the ultrasonic-assisted extraction of total coumarins from Peucedanum decursivum (Miq.) Maxim (P. decursivum) via the combination of deep eutectic solvents (DESs) with cellulase pretreatment was carried out. Among the 15 kinds of DESs with choline chloride as hydrogen bond acceptors, the DES system of choline chloride/1,4-butanediol with a molar ratio of 1:4 showed the best extraction effect. First, single-factor experiments were performed using the following factors: liquid-solid ratio, pH, enzyme dosage and ultrasonic temperature. The Box-Behnken design (BBD) and response surface methodology (RSM) were employed to optimize the extraction conditions and obtain the following optimal parameter values for the extraction of coumarins from P. decursivum: liquid-solid ratio 14:1 mL/g, pH 5.0, enzyme dosage 0.2%, ultrasonic temperature 60 °C and ultrasonic time 50 min. Under these conditions, the extraction yield of total coumarins from P. decursivum could reach 2.65%, which was close to the predicted extraction yield of 2.68%. Furthermore, the contents of six coumarins, namely, umbelliferone, nodakenin, xanthotoxin, bergapten, imperatorin and decursin were determined to be 0.707 mg·g-1, 0.085 mg·g-1, 1.651 mg·g-1, 2.806 mg·g-1, 0.570 mg·g-1 and 0.449 mg·g-1, respectively, using HPLC-MS after the optimization. In addition, the cell fragmentation of P. decursivum powder obtained using ultrasonic-assisted DES extraction with enzyme pretreatment was found to be the most comprehensive using scanning electron microscopy (SEM), which indicated the highest extraction efficiency for P. decursivum. Finally, the in vitro antioxidant activity of the extracts was evaluated via radical scavenging with 1,1-diphenyl-2-picrylhydrazyl (DPPH), which showed that ultrasonic-assisted DES extraction with enzyme pretreatment exhibited significant antioxidant activity with DPPH radical scavenging of up to 97.90%. This work developed a new and efficient extraction method for coumarins.


Assuntos
Antioxidantes , Ultrassom , Antioxidantes/química , Colina , Cumarínicos/química , Solventes Eutéticos Profundos , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Solventes/química
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