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1.
Yakugaku Zasshi ; 140(8): 1001-1006, 2020.
Artigo em Japonês | MEDLINE | ID: mdl-32741857

RESUMO

Ascertaining the absorption, distribution, metabolism, and excretion (ADME) profile of drugs is one of the most crucial factors in the process of drug discovery. Since it is important to combine water solubility and cell permeability within the compound to achieve the desired ADME properties, an appropriate balance between lipophilicity and hydrophilicity is required. It is often necessary to facilitate hydrophilicity of very hydrophobic candidates, because quite lipophobic molecules are rarely hit as positive in molecular-targeted or cell-based screenings. For that purpose, it has been popular to conjugate hydrophobic molecules with polyethylene glycol (PEG). However, PEG is a polymer, and PEG-conjugated molecules are not uniform. Besides, the dosage should be much increased compared with the original molecule due to the increase in molecular weight. Therefore we have been developing alternative ways to endow hydrophobic compounds with extra hydrophilicity by conjugating with symmetrically branched glycerol oligomers. This technology is versatile and easily applicable to various hydrophobic compounds. Water-solubility of fenofibrate, one of the most hydrophobic medicines in clinical use, was facilitated by a factor of more than 2000, and its lipid-lowering effect in vivo improved more than ten-fold, by simply conjugating with branched glycerol trimer, for instance. Here we will briefly introduce the basic concepts and our successful experiences of applying branched glycerol oligomers including antitumor agents in terms of water-solubility, pharmacological effects, and pharmacokinetics, and merits and current issues will be discussed in this review.


Assuntos
Antineoplásicos , Glicerol/química , Interações Hidrofóbicas e Hidrofílicas , Antineoplásicos/farmacocinética , Antineoplásicos/farmacologia , Ácidos Fíbricos , Polietilenoglicóis/química , Polímeros , Solubilidade , Água
2.
Food Chem ; 329: 127085, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-32512390

RESUMO

The refractive index is a basic optical property of materials. This study explores the effect of ethanol, glycerol, tartaric acid and glucose/fructose on the refractive index in model aqueous solutions and in dry white wines. Various model aqueous solutions consisting of these components were prepared and the refractive index was measured at 20 °C and each component was studied both alone and in mixtures with the others. The refractive index of white dry wines samples was also measured. A linear regression analysis was performed and linear multi-dependence equations were derived. The resulting regression models had a coefficient of determination over 97.3%. Glucose/fructose was found to have the greatest effect on the refractive index, followed by tartaric acid and glycerol while ethanol had the smallest effect. The knowledge of the correlation of the concentration of each wine component to the refractive index can be of value for the estimation of fermentation kinetics.


Assuntos
Etanol/química , Frutose/química , Glucose/química , Glicerol/química , Tartaratos/química , Água/química , Vinho/análise , Refratometria
3.
Chemosphere ; 257: 127012, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32497843

RESUMO

Research on the production of Glycerol Monostearate from glycerol using dealuminated Zeolite Y catalysts has been carried out. Optimization of the dealumination process is conducted using the help of statistical software 10, where the variables used are acid concentration (5-7 M), temperature of dealumination (55-70 °C) and time of dealumination (2-6 h). The acidity characterization test of dealuminated Zeolite Y using ammonia and pyridine solution. Glycerol Monostearate yield was obtained by GC-MS test that was carried out on 2 samples zeolite Y catalyst with the highest value of total and surface acidity of zeolite Y which produced 2.18% and 4% yield of Glycerol Monostearate. The two samples showed that the greater the acidity, the GMS yield was also greater. Compared to previous studies it was found that ZSM-5 catalyst has a higher acidity value than zeolite Y so that the yield of Glycerol Monostearate is higher with the use of ZSM-5 than Zeolite Y.


Assuntos
Modelos Químicos , Zeolitas/química , Catálise , Glicerol/química , Estearatos , Temperatura
4.
Food Chem ; 329: 127213, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-32516713

RESUMO

Chitosan and whey protein isolate (WPI) conjugate films were prepared as a novel matrix for encapsulating and extending the postharvest shelf life of strawberries. Film forming solutions of chitosan, WPI, and chitosan-WPI conjugate were mixed with glycerol, casted for films at 60 ± 2 °C and assessed for their colour, water vapour and oxygen transfer rate, textural, functional groups and secondary structure, thermal, crystallinity, and antioxidant properties. Chitosan-WPI conjugate films were applied as an edible coating on strawberries, and studied for storage stability at 5 °C and 20 °C by assessing physical and biochemical parameters. A considerable reduction in colour indices, weight loss, pH and titratable acidity, reducing sugars, ascorbic acid, total phenolics, DPPH and ABTS assay was noted in the coated strawberries over the control at both the studied temperatures. The control strawberries had a shelf life of 5 and 3 days, whereas coating enhanced the shelf life of strawberries to 8 and 5 days when stored at 5 °C and 20 °C, respectively.


Assuntos
Quitosana/química , Conservação de Alimentos/métodos , Proteínas do Soro do Leite/química , Antioxidantes/química , Ácido Ascórbico/análise , Varredura Diferencial de Calorimetria , Cor , Fragaria/química , Fragaria/metabolismo , Frutas/química , Frutas/metabolismo , Glicerol/química , Concentração de Íons de Hidrogênio , Fenóis/análise , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura
5.
Food Chem ; 327: 127014, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32434126

RESUMO

The influence of diacylglycerol (DAG) combined with polyglycerol polyricinoleate (PGPR) on the stability of water-in-oil (W/O) emulsions containing hydrogenated palm oil (HPO) was studied. Polarized light microscope revealed that DAG promoted HPO to crystallize at the water-oil interface, providing the combination of Pickering and network stabilization effects. It was proposed that the molecular compatibility of fatty acids in DAG with HPO accounted for the promotional effect. The interfacial crystallization of DAG together with the surface activity of PGPR led to the formation of emulsions with uniform small droplets and high freeze-thaw stability. Further exploration of physical properties indicated that the combination of DAG and PGPR dramatically improved the emulsion's viscoelasticity and obtained a larger deformation yield. Water droplets in DAG-based emulsions acted as active fillers to improve the network rigidity. Therefore, DAG is a promising material to be used as emulsifier to enhance the physical stability of W/O emulsions.


Assuntos
Diglicerídeos/química , Emulsões/química , Cristalização , Congelamento , Glicerol/análogos & derivados , Glicerol/química , Óleo de Palmeira/química , Óleo de Brassica napus/química , Ácidos Ricinoleicos/química , Viscosidade , Água/química
6.
Nat Commun ; 11(1): 2139, 2020 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-32358489

RESUMO

A longstanding goal in science and engineering is to mimic the size, structure, and functionality present in biology with synthetic analogs. Today, synthetic globular polymers of several million molecular weight are unknown, and, yet, these structures are expected to exhibit unanticipated properties due to their size, compactness, and low inter-chain interactions. Here we report the gram-scale synthesis of dendritic polymers, mega hyperbranched polyglycerols (mega HPGs), in million daltons. The mega HPGs are highly water soluble, soft, nanometer-scale single polymer particles that exhibit low intrinsic viscosities. Further, the mega HPGs are lubricants acting as interposed single molecule ball bearings to reduce the coefficient of friction between both hard and soft natural surfaces in a size dependent manner. We attribute this result to their globular and single particle nature together with its exceptional hydration. Collectively, these results set the stage for new opportunities in the design, synthesis, and evaluation of mega polymers.


Assuntos
Dendrímeros/química , Glicerol/química , Lubrificantes/química , Nanotecnologia/métodos , Polímeros/química , Substâncias Macromoleculares/química , Propriedades de Superfície
7.
J Oleo Sci ; 69(4): 277-295, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32249258

RESUMO

Fatty acid and monoglyceride are examples of lipid compounds that can be founded in vegetable oils. The fatty acid has an important role in the human diet, lubricants, detergents, cosmetics, plastics, coatings, and resin. Monoglyceride has a wide function in the food industry in particular as natural emulsifier, pharmaceuticals, cosmetics, antioxidant, and antibacterial. Therefore, isolation and preparation of fatty acid and monoglyceride are the crucial step. This article focuses on providing the chemical reaction paths of isolation fatty acid and synthesis of monoglyceride from vegetable oils. Fatty acids could be isolated by Colgate-Emery steam hydrolysis, hydrolysis of vegetable oils using inorganic base catalyst or lipase, and base-catalyzed hydrolysis of pure fatty acid methyl ester. There are three steps in the synthesis of pure fatty acid methyl ester which are neutralization, transesterification, and fractional distillation. There are four reactions paths in preparing monoglyceride from vegetable oils. They are glycerolysis, ethanolysis using lipase enzyme (sn-1,3), esterification of fatty acid with glycerol in the presence of inorganic acid catalyst or lipase, transesterification of fatty acid methyl ester with glycerol, transesterification of fatty acid methyl ester with protected glycerol (1,2-O-isopropylidene glycerol), and deprotection using an acid resin (Amberlyst-15).


Assuntos
Ácidos Graxos/isolamento & purificação , Monoglicerídeos/síntese química , Óleos Vegetais/química , Catálise , Esterificação , Ésteres , Ácidos Graxos/química , Glicerol/química , Hidrólise , Lipase , Estirenos
8.
J Oleo Sci ; 69(4): 347-358, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32249262

RESUMO

In this study, Lecitase® Ultra (LU) was immobilized onto the parent and the amino-functionalized SBA-15. The immobilization conditions were studied and the activity of the parent SBA-15 supported LU (SBA-15-LU) was found to be at 2177.78 ± 101.84 U/g. After 3-aminopropyl and n-(2-aminoethyl)-3-aminopropyl groups functionalization, enzymatic activity was increased to 3555.56 ± 200.21 and 3444.44 ± 346.41 U/g respectively. The immobilized LU samples were then used to catalyze glycerolysis. The possibility for diacylglycerols (DAG) and monoacylglycerols (MAG) production was evaluated and it was found only suitable for DAG production. In addition, the glycerolysis activity of the immobilized LU was impaired by the tert-pentanol and solvent-free was found suitable. Similar DAG content over 50 wt% could be obtained from glycerolysis by the three immobilized LU samples. The reusability in glycerolysis was evaluated, and 9.79 % of the initial glycerolysis activity was remained from the SBA-15-LU after 5 cycles of reuse. Encouragingly, after 3-aminopropyl and n-(2-aminoethyl)-3-aminopropyl groups functionalization, 62.93 and 83.91% of their initial activity was respectively remained after 5 cycles of reuse.


Assuntos
Enzimas Imobilizadas/química , Glicerol/síntese química , Dióxido de Silício/química , Catálise , Glicerol/química
9.
Int J Nanomedicine ; 15: 735-747, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32099362

RESUMO

Introduction: Gambogic acid (GA) is proved to have anti-tumor effects on gastric cancer. Due to poor solubility, non-specific biological distribution, toxicity to normal tissues and short half-life, it is hard to be applied into the clinic. To overcome these issues, we developed a thermosensitive and injectable hydrogel composed of hydroxypropyl cellulose, silk fibroin and glycerol, with short gelling time, good compatibility and sustained release, and demonstrated that the hydrogel packaged with gambogic acid nanoparticles (GA-NPs) and tumor-penetrating peptide iRGD could improve the anti-tumor activity. Methods: The Gelling time and micropore size of the hydrogels were regulated through different concentrations of glycerol. Controlled release characteristics of the hydrogels were evaluated with a real-time near-infrared fluorescence imaging system. Location of nanoparticles from different carriers was traced by confocal laser scanning microscopy. The in vivo antitumor activity of the hydrogels packaging GA-NPs and iRGD was evaluated by investigating tumor volume and tumor size. Results: The thermo-sensitive properties of hydrogels were characterized by 3-4 min, 37°C, when glycerol concentration was 20%. The hydrogels physically packaged with GA-NPs and iRGD showed higher fluorescence intensity than other groups. The in vivo study indicated that the co-administration of GA-NPs and iRGD by hydrogels had higher antitumor activity than the GA-loaded hydrogels and free GA combining with iRGD. Free GA group showed few antitumor effects. Compared with the control group, the body weight in other groups had no obvious change, and the count of leukocytes and hemoglobin was slightly decreased. Discussion: The hydrogel constructed iRGD and GA-NPs exerted an effective anti-tumor effect possibly due to retention effect, local administration and continuous sustained release of iRGD promoting the penetration of nanoparticles into a deep part of tumors. The delivery system showed little systemic toxicity and would provide a promising strategy to improve anti-gastric cancer efficacy.


Assuntos
Antineoplásicos/uso terapêutico , Hidrogéis/química , Nanopartículas/química , Oligopeptídeos/farmacologia , Neoplasias Gástricas/tratamento farmacológico , Temperatura , Xantonas/uso terapêutico , Animais , Antineoplásicos/farmacologia , Bombyx , Linhagem Celular Tumoral , Fibroínas/química , Glicerol/química , Humanos , Derivados da Hipromelose/química , Masculino , Camundongos Endogâmicos BALB C , Camundongos Nus , Nanopartículas/ultraestrutura , Porosidade , Neoplasias Gástricas/patologia , Distribuição Tecidual , Xantonas/farmacologia
10.
J Biotechnol ; 310: 97-102, 2020 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-32035905

RESUMO

The immobilization of lipases in cross linked aggregates (CLEA) leads to a robust biocatalyst that remains very stable in low viscous non-conventional Deep Eutectic Solvents - Buffer mixtures. To reinforce that stability, and to facilitate the biocatalyst recovery, this paper explores the immobilization of Lipase-CLEA derivatives in Lentikats®. This double immobilization can be successfully used in esterifications in DES-buffer media, using substrates of unpaired solubilities (e.g. benzoic acid and glycerol), in batch and continuous processes, and reaching full conversion. Under these conditions, the derivatives display an improved stability (compared to the Lipase-CLEA derivatives) and enable the reuse of the reaction media in continuous devices for at least 6 cycles under non-optimized conditions, accumulating 10 g product L-1, enhancing the productivity, and opening exciting future options for sustainable chemistry.


Assuntos
Ácido Benzoico/química , Enzimas Imobilizadas/química , Glicerol/química , Lipase/química , Biocatálise , Reagentes para Ligações Cruzadas/química , Estabilidade Enzimática , Esterificação , Solventes/química
11.
J Agric Food Chem ; 68(4): 989-997, 2020 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-31909616

RESUMO

In the previous studies, gemini lipoamino acids (GLAA) were always synthesized by complex multistep organic synthesis, which involved a large number of byproducts and organic solvents. To develop a straightforward, efficient, and renewable synthesis strategy for GLAA, in this study, a type of novel green solvents, natural deep eutectic solvents (NADESs), were adopted as the solvents for these reactions. Five commercial enzymes were involved in the enzyme screening section, and Candida antarctica lipase B (CALB) tended to have the best performance in NADESs systems. The optimization procedure was performed using the Taguchi crossed array method and the highest yield of GLAA (59.14 ± 0.51%) was obtained in choline chloride-glycerol (C-Gly). The purification procedure was carried out with ethyl acetate and water, and the isolate yield ranged from 86.31 ± 2.36 to 91.34 ± 2.26%. With 10 times recycling, the yield of GLAA in C-Gly decreased from 59.14 ± 0.51 to 51.31 ± 0.68%. Interestingly, a synergistic effect of CALB and NADESs was found in the enzymatic synthesis of GLAA, which can be attributed to fatty acids being activated by chloride ions via hydrogen-bonding interactions and resulting in an enhancement in its electron-attracting ability.


Assuntos
Aminoácidos/síntese química , Proteínas Fúngicas/química , Lipase/química , Aminoácidos/química , Catálise , Glicerol/química , Ligação de Hidrogênio , Solventes/química
12.
J Agric Food Chem ; 68(5): 1347-1353, 2020 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-31961681

RESUMO

A facile approach is introduced here for the synthesis of rare ketoses from glycerol and d-/l-glyceraldehyde (d-/l-GA). The reactions were carried out in a one-pot multienzyme fashion in which the only carbon source is glycerol. In the enzymatic cascade, glycerol is phosphorylated and then oxidized at C2 to afford dihydroxyacetone phosphate (DHAP), the key donor for enzymatic aldol reaction. Meanwhile, the primary alcohol of glycerol is also oxidized to give the acceptor molecule GA in situ (d- or l-isomer could be formed stereospecifically with either alditol oxidase or horse liver alcohol dehydrogenase). Different DHAP-dependent aldolases were used to generate the aldol adducts (rare ketohexose phosphates) with various stereoconfigurations and diastereomeric ratios. It is worth noting that the enzyme that catalyzes the phosphorylation reaction in the first step could also help recycle the phosphate in the last step to provide free rare sugar molecules. This study provides a useful method for rare ketose synthesis on a 100 mg to g scale, starting from relatively inexpensive materials which solved the problem of supplying both glycerol 3-phosphate and GA in our previous work. It also demonstrates an example of green synthesis due to highly efficient carbon usage and recycling of cofactors.


Assuntos
Álcool Desidrogenase/química , Aldeído Liases/química , Glicerol/química , Cetoses/química , Animais , Biocatálise , Fosfato de Di-Hidroxiacetona/química , Cavalos , Fosforilação
13.
Food Chem ; 314: 126174, 2020 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-31981885

RESUMO

The aim of this work is to develop a W1/O/W2 multiple emulsion with gallic acid in the internal aqueous phase (W1). A quantification method for gallic acid using HPLC-UV was developed and validated. In the first step, a simple W1/O emulsion was prepared with distilled water, polyglycerol polyricinoleate, sodium chloride, gallic acid and pH 5.0 sodium acetate buffer system. The second step consisted of adding the simple emulsion to the external aqueous phase (W2) composed of distilled water, polysorbate 80 and xanthan gum. The multiple emulsion showed pseudoplastic behavior. After 28 days of analysis the multiple emulsion presented a stability index of 75% without pH variation, 89.61% of gallic acid concentration, 59.62% of antioxidant activity in the phosphomolybdenum complex assay and 80.58% of DPPH scavenging activity. It is concluded that the W1/O/W2 emulsion developed was stable for 28 days and maintained more than 50% of gallic acid antioxidant capacity.


Assuntos
Ácido Gálico/química , Emulsões , Glicerol/análogos & derivados , Glicerol/química , Óleo de Brassica napus/química , Ácidos Ricinoleicos/química , Cloreto de Sódio/química , Viscosidade , Água/química
14.
Environ Sci Pollut Res Int ; 27(2): 1461-1474, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31749007

RESUMO

Anaerobic digestion of crude glycerol from biodiesel production is a feasible way for methane production. However, crude glycerol (CG) contains impurities, such as long-chain fatty acids (LCFA) that can inhibit methanogenic microorganisms. Ultrasound promotes the hydrolysis of LCFA and deagglomerates the microorganisms in biological flocs. Furthermore, Aspergillus niger and Escherichia coli produce lipases capable of degrading LCFA. This study aims at improving the methane yield from anaerobic digestion by coupling with ultrasound or E. coli/A. niger biodegradation. The effect of the different treatments was first assessed in a perfectly mixed batch reactor (PMBR), using diluted CG at concentrations of 0.2%, 1.7%, and 3.2% (v/v). Later, the best conditions were replicated in an upflow anaerobic sludge blanket (UASB) reactor to simulate full-scale practical applications. Experiments in the PMBR showed that ultrasound or A. niger biodegradation steps improved methane yield up to 11% for 0.2% CG and 99% for 1.7% CG, respectively. CG biodegradation by E. coli inhibited the subsequent anaerobic digestion for all concentrations tested. Using a UASB digester, ultrasonic treatment of CG led to an average increase of 29% in methane production. The application of ultrasound led to a lower accumulation of propionic acid in the digested material and increased biogas production. On the other hand, an average 77% increase in methane production was achieved using a preliminary CG biodegradation step by A. niger, when operated at a loading rate of 2.9 kg COD m-3 day-1. Under these conditions, an energy gain of 0.48 kWh day-1, with the production of the 0.434 m3 CH4 kg-1 CODremoval and 0.573 m3 CH4 kg-1 VS, and a biogas quality of 73% in methane were obtained. The digested material was analyzed for the detection and quantification of added-value by-products in order to obtain a broad assessment of the CG valorization through anaerobic digestion. In some experiments, propionic and oxalic acid were detected. However, the accumulation of propionic caused the inhibition of the acetogenic and methanogenic microorganisms.


Assuntos
Reatores Biológicos , Glicerol/química , Glicerol/metabolismo , Metano , Esgotos/química , Anaerobiose , Escherichia coli
15.
ChemSusChem ; 13(3): 564-573, 2020 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-31808287

RESUMO

Electrofermentation actively regulates the bacterial redox state, which is essential for bioconversion and has been highlighted as an effective method for further improvements of the productivity of either reduced or oxidized platform chemicals. 1,3-Propanediol (1,3-PDO) is an industrial value-added chemical that can be produced from glycerol fermentation. The bioconversion of 1,3-PDO from glycerol requires additional reducing energy under anoxic conditions. The cathode-based conversion of glycerol to 1,3-PDO with various electron shuttles (2-hydroxy-1,4-naphthoquinone, neutral red, and hydroquinone) using Klebsiella pneumoniae L17 was investigated. The externally poised potential of -0.9 V vs. Ag/AgCl to the cathode increased 1,3-PDO (35.5±3.1 mm) production if 100 µm neutral red was used compared with non-bioelectrochemical system fermentation (23.7±2.4 mm). Stoichiometric metabolic flux and transcriptional analysis indicated a shift in the carbon flux toward the glycerol reductive pathway. The homologous overexpression of glycerol dehydratase (DhaB) and 1,3-PDO oxidoreductase (DhaT) enzymes synergistically enhanced 1,3-PDO conversion (39.3±0.8 mm) under cathode-driven fermentation. Interestingly, a small current uptake (0.23 mmol of electrons) caused significant metabolic flux changes with a concomitant increase in 1,3-PDO production. This suggests that both an increase in 1,3-PDO production and regulation of the cellular metabolic pathway are feasible by electrode-driven control in cathodic electrofermentation.


Assuntos
Glicerol/química , Klebsiella pneumoniae/metabolismo , Propilenoglicóis/química , Técnicas Eletroquímicas/métodos , Eletrodos , Transporte de Elétrons , Fermentação , Hidroliases/metabolismo , Hidroquinonas/química , Naftoquinonas/química , Vermelho Neutro/química , Oxirredução , Oxirredutases/metabolismo , Transdução de Sinais
16.
Food Chem ; 308: 125596, 2020 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-31648097

RESUMO

The protective mechanism of glycerol on ß-lactoglobulin were studied in 0-60% glycerol solutions by experimental and molecular simulation approaches. Results showed that the stability of ß-lactoglobulin increased with glycerol concentration, with little secondary structure changes induced by glycerol. The tertiary structure altered slightly with glycerol concentration, resulting in a stronger near UV circular dichroism signal and intrinsic tryptophan fluorescence quenching, indicating aromatic side chains closer to hydrophobic microenvironment. The Rg of ß-lactoglobulin increased with glycerol concentration without dimer dissociation, due to expansion of the quaternary structures. Moreover, the flexibility (RMSF) of ß-lactoglobulin decreased by glycerol. Distance between areas enclosing Asp33 and Arg40 from separate chains did not increase, suggesting possibly reinforced electrostatic attractions. In conclusion, the stabilization of ß-lactoglobulin in glycerol solution is probably the comprehensive results of the decreased molecular flexibility, the strengthened hydrophobic interaction in individual chain, and the possibly reinforced electrostatic attractions between two chains of ß-lactoglobulin.


Assuntos
Glicerol/química , Lactoglobulinas/química , Dicroísmo Circular , Interações Hidrofóbicas e Hidrofílicas , Modelos Moleculares , Estrutura Secundária de Proteína , Estrutura Terciária de Proteína
17.
Food Chem ; 307: 125542, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31639573

RESUMO

This study aimed to develop a headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC-MS) method for the quantification of 3-monochloropropane-1,2-diol fatty acid esters (3-MCPDEs) and 2-monochloropropane-1,3-diol fatty acid esters (2-MCPDEs), and semi-quantification of glycidyl fatty acid esters (GEs) in edible oils. A central composite design was implemented to optimize the derivatization temperature and extraction time, which were 100 °C and 80 min, respectively. HS-SPME coupled with in-situ derivatization was more straightforward (three steps) and sensitive, with a limit of detection of 16% (3.9 µg/L) and 11% (5.3 µg/L) higher than that of liquid injection method, for 3-MCPD and 2-MCPD, respectively. The recoveries of 3-MCPD and 2-MCPD were in the range of 91.1% to 102.1%, with a relative standard deviation ranging from 0.08 to 9.29%. The validated methodology was successfully applied to oil samples. Further efforts will focus on shortening the extraction time, as 80 min is relatively long.


Assuntos
Ésteres/análise , Cromatografia Gasosa-Espectrometria de Massas , Glicerol/análogos & derivados , Óleos Vegetais/química , Microextração em Fase Sólida/métodos , alfa-Cloridrina/química , Ésteres/química , Ácidos Graxos/química , Contaminação de Alimentos/análise , Glicerol/química , Limite de Detecção
18.
Mater Sci Eng C Mater Biol Appl ; 106: 110293, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31753347

RESUMO

The inadequate donor source and the difficulty of using natural grafts in tendon repair and regeneration has led researchers to develop biodegradable and biocompatible synthetic based tissue equivalents. Poly(glycerol sebacate) (PGS) is a surface-erodible bioelastomer and has been increasingly investigated in a variety of biomedical applications. In this study, PGS elastomeric sheets were prepared by using a facile microwave method and used as elastomeric platform for the first time under mechanical stimulation to induct the tenocyte gene expression. It is revealed that elastomeric PGS sheets promote progenitor tendon cell structure by increasing proliferation and gene expression with regard to tendon extracellular matrix components. Human tenocytes were seeded onto poly(glycerol-sebacate) sheets and were cultured two days prior to transfer to dynamic culture in a bioreactor system. Cell culture studies were carried out for 12 days under 0%, 3% and 6% strain at 0.33 Hz. The PGS-cell constructs were examined by using Scanning Electron Microscopy (SEM), cell viability via live/dead staining using confocal microscopy, and GAG/DNA analysis. In addition, gene expression was examined using real-time polymerase chain reaction (RT-PCR). Tenocytes cultured upon PGS scaffolds under 6% cyclic strain exhibited tendon-like gene expression profile compared to 3% and 0% strain groups. The results of this study show that PGS is a suitable material in promoting tendon tissue formation under dynamic conditions.


Assuntos
Decanoatos/química , Glicerol/análogos & derivados , Polímeros/química , Materiais Biocompatíveis/química , Materiais Biocompatíveis/farmacologia , Reatores Biológicos , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Decanoatos/farmacologia , Glicerol/química , Glicerol/farmacologia , Humanos , Polímeros/farmacologia , Tenócitos/citologia , Tenócitos/metabolismo , Tecidos Suporte/química , Transcriptoma/efeitos dos fármacos , Regulação para Cima/efeitos dos fármacos
19.
Biophys Chem ; 257: 106274, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31877449

RESUMO

An orderly investigation of the levels of secondary and tertiary structures, kinetics of tertiary structural changes, and self diffusion coefficient of lysozyme and cytochrome c in the 0-70% (weight/volume) range of glycerol is reported. While secondary structural propensity of both proteins is larger in glycerol, results for tertiary structure and translational diffusion coefficient with increasing glycerol provide two contrasting depictions - lysozyme becomes increasingly compact, plausibly due to disulfide bridge constraints, but cytochrome c expands and loses the tertiary structure. The chain expansion and contraction corresponding to loss and reformation of tertiary structure of cytochrome c are ultrafast that occur in the submillisecond bin. Changes in protein conformation appear in as little as 2% glycerol, and the results suggest that glycerol does not unfold the protein but reversibly destabilizes to quasi-native state(s). These observations make one ponder whether results of studies on protein dynamics, relaxation, and conformational substates reported in literature can be associated with native-state properties.


Assuntos
Citocromos c/química , Glicerol/química , Muramidase/química , Água/química , Difusão , Cinética , Dobramento de Proteína , Estrutura Secundária de Proteína , Termodinâmica
20.
Food Chem ; 305: 125453, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31505417

RESUMO

Impact of glycerol and sorbitol on assembly of iron-bound ovotransferrin (OVT) into nanofibrils was investigated. Thioflavin T fluorescence result indicated that the presence of glycerol or sorbitol could reduce the rate of OVT fibrillation. Sodium dodecyl sulfate polyacrylamide gel electrophoresis demonstrated that 60% sorbitol could retard hydrolysis of OVT completely for a period of time during thermal treatment, and decoupling hydrolysis from fibril self-assembly helped to identify the building blocks of OVT nanofibrils. OVT nanofibrils were composed of both intact OVT monomers and OVT-derived peptides. Influence of glycerol and sorbitol on morphology of OVT nanofibrils was studied using atomic force microscopy. The presence of glycerol or sorbitol shortened OVT nanofibrils, and the presence of 60% glycerol or sorbitol could increase thickness of OVT nanofibrils. Hopefully, this work may provide new insight about building blocks of protein nanofibrils and impact of polyols on protein fibrillation.


Assuntos
Conalbumina/química , Glicerol/química , Nanoestruturas/química , Sorbitol/química , Temperatura Alta , Interações Hidrofóbicas e Hidrofílicas , Microscopia de Força Atômica , Propriedades de Superfície
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