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1.
Int J Biol Macromol ; 267(Pt 2): 131634, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38636747

RESUMO

Oxidative damage is an important cause of aging. The antioxidant and anti-aging activities of Longan polysaccharides, especially purified Longan polysaccharides, have not been thoroughly investigated. Therefore, this study aimed to investigate the antioxidant and anti-aging activities and mechanisms of crude polysaccharides and purified polysaccharides from Longan. A purified acidic Longan polysaccharide LP-A was separated from Longan crude polysaccharide LP. Subsequently, its structural characterization, anti-aging activity and mechanism were studied. The results showed that LP-A was an acidic heteropolysaccharide with an average molecular weight (Mw) of 4.606 × 104 Da which was composed of nine monosaccharides. The scavenging rate of ABTS free radical in vitro reached 99 %. In the nematode life experiment, 0.3 mg/mL LP group and LP-A group could prolong the average lifespan of nematodes by 9.31 % and 25.80 %, respectively. Under oxidative stress stimulation, LP-A group could prolong the survival time of nematodes by 69.57 %. In terms of mechanism, Longan polysaccharide can regulate insulin / insulin-like growth factor (IIS) signaling pathway, increase the activity of antioxidant enzymes, reduce lipid peroxidation, enhance the body's resistance to stress damage, and effectively prolong the lifespan of nematodes. In conclusion, LP-A has better anti-aging activity than crude polysaccharide LP, which has great potential for developing as an anti-aging drug.


Assuntos
Envelhecimento , Antioxidantes , Caenorhabditis elegans , Estresse Oxidativo , Polissacarídeos , Animais , Caenorhabditis elegans/efeitos dos fármacos , Polissacarídeos/farmacologia , Polissacarídeos/química , Polissacarídeos/isolamento & purificação , Antioxidantes/farmacologia , Antioxidantes/química , Envelhecimento/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Peroxidação de Lipídeos/efeitos dos fármacos , Peso Molecular , Monossacarídeos/análise , Longevidade/efeitos dos fármacos
2.
Heliyon ; 10(7): e27828, 2024 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-38596067

RESUMO

Objective: As a traditional Chinese medicine, leech has obvious pharmacological activities in anticoagulantion and antithrombosis. Whitmania pigra Whitman (WP) is the most commonly used leech in the Chinese market. It is often used in clinical applications after high-temperature processing by talcum powder to remove the fishy taste and facilitate crushing. The anticoagulant and thrombolytic active ingredients are protein and polypeptide, which may denaturate and lose activity after high-temperature processing. The rationality of its processing has been questioned in recent years. This study aims to investigate the effect of talcum powder scalding on the antithrombotic activity of WP in vivo and to discuss its pharmacodynamic mechanism in vivo. Methods: Raw and talcum-powdered processed WP were administered intragastrically for 14 days, and carrageenan was injected intraperitoneally to prepare a mouse model of tail vein thrombosis. The incidence rate of tail vein thrombosis and the thrombus area under pathological tissue sections were calculated to evaluate the antithrombotic effect between raw and processed WP. Non-targeted metabolomics was conducted using UPLC-Q-TOF/MS technology to analyze the changes of small molecule metabolites in the body after administration of WP. Results: After intragastric administration, both the raw product and the processed product of WP could inhibit the thrombosis induced by carrageenan, and the processed product had a more apparent antithrombotic effect than the raw product. The administration of WP could regulate the changes of some small molecular metabolites, such as amino acids, lipids, and steroids, in Sphingolipid metabolism and Glycerophospholipid metabolism. Conclusions: Based on the results of pharmacodynamics and metabolomics, processed WP will not reduce the antithrombotic activity of WP. This study provided a scientific basis for the rational use of leeches.

3.
Fitoterapia ; 175: 105908, 2024 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-38479621

RESUMO

Three undescribed sesquiterpenes, designed as pichinenoid A-C (1-3), along with nine known ones (4-12) were isolated from the stems and leaves of Picrasma chinensis. The new isolates including their absolute configurations were elucidated based on extensive spectroscopic methods, single crystal X-ray diffraction, and electronic circular dichroism (ECD) experiments, as well as comparison with literature data. Structurally, compounds 1 and 2 are descending sesquiterpenes, while pichinenoid C (3) is a rare sesquiterpene bearing a 2-methylenebut-3-enoic acid moiety at the C-6 side chain. All the isolated compounds were tested for their neuroprotective effects against the H2O2-induced damage on human neuroblastoma SH-SY5Y cells, and most of them showed moderate neuroprotective activity. Especially, compounds 1, 3-5, and 7 showed a potent neuroprotective effect at 25 or 50 µM. Moreover, the neuroprotective effects of compounds 1 and 4 were tested on a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced Parkinson's disease (PD) mouse model. Results of western blot and immunofluorescence indicated that compound 4 significantly counteract the toxicity of MPTP, and reversed the expression of tyrosine hydroxylase (TH) in substantia nigra (SN) and striatum (ST) of the mouse brain. Interestingly, western blot data suggested compound 4 also enhanced B-cell lymphoma-2 (Bcl-2) and heme oxygenase 1 (HO-1) expressions in the brain tissues from MPTP damaged mouse.

4.
Front Pharmacol ; 14: 1282077, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38044947

RESUMO

Background: Yuquan Pill (YQW) is a modern concentrated pill preparation of six herbs, namely, Ge Gen (Pueraria lobata Ohwi), Di huang (Rehmannia glutinosa Libosch.), Tian Huafen (Trichosanthes kirilowii Maxim.), Mai Dong (Ophiopogon japonicus (L. f.) Ker Gawl.), Wu Weizi (Schisandra chinensis (Turcz.) Baill.) and Gan Cao (Glycyrrhiza uralensis Fisch.). It is extensively used to treat type 2 diabetes-related glucose and lipid metabolism disorders. But what's the pharmacodynamic substance and how it works in the treatment of Type 2 diabetes mellitus (T2DM) are still unclear. Purpose: The purpose of this study is to determine the likely pharmacological components and molecular mechanism of YQW's intervention on T2DM by combining serum pharmacochemistry, network analysis and transcriptomics. Methods: The efficacy and prototypical components of blood entry were determined after oral administration of YQW aqueous solution to T2DM rats induced by high-fat feed and low-dose streptozotocin (STZ), and the key targets and pathways for these compounds to intervene in T2DM rats were predicted and integrated using network analysis and transcriptomics techniques. Results: In diabetic rats, YQW can lower TG, CHO, NO, and MDA levels (p < 0.05) while increasing HDL-C levels (p < 0.01), and protecting the liver and kidney. 22 prototype components (including puerarin, daidzein, 3'-methoxypuerarin, and liquiritigenin, among others) were found in the serum of rats after oral administration of YQW for 90 min, which might be used as a possible important ingredient for YQW to intervene in T2DM rats. 538 YQW pharmacodynamic components-related targets and 1,667 disease-related targets were projected through the PharmMapper database, with 217 common targets between the two, all of which were engaged in regulating PI3K-Akt, MAPK, Ras and FoxO signal pathway. Finally, the mRNA expression profiles of liver tissues from rats in the control, model, and YQW groups were investigated using high-throughput mRNA sequencing technology. YQW can regulate the abnormal expression of 89 differential genes in a disease state, including 28 genes with abnormally high expression and 61 genes with abnormally low expression. Five common genes (Kit, Ppard, Ppara, Fabp4, and Tymp) and two extensively used regulatory pathways (PI3K-Akt and MAPK signaling pathways) were revealed by the integrated transcriptomics and network analysis study. Conclusion: The mechanism of YQW's intervention in T2DM rats could be linked to 22 important components like puerarin, daidzein, and glycyrrhetinic acid further activating PI3K-Akt and MAPK signaling pathways by regulating key targets Kit, Ppard, Ppara, Fabp4, and Tymp, and thus improving lipid metabolism disorder, oxidative stress, and inflammation levels in T2DM rats. On the topic, more research into the pharmacological ingredient foundation and mechanism of YQW intervention in T2DM rats can be done.

5.
Front Immunol ; 14: 1131933, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36936921

RESUMO

Introduction: Rheumatoid arthritis (RA) is a multifactorial autoimmune disease. Recently, growing evidence demonstrates that gut microbiota (GM) plays an important role in RA. But so far, no bibliometric studies pertaining to GM in RA have ever been published. This study attempts to depict the knowledge framework in this field from a holistic and systematic perspective based on the bibliometric analysis. Methods: Literature related to the involvement of GM in RA was searched and picked from the Web of Science Core Collection (WOSCC) database. The annual output, cooperation, hotspots, research status and development trend of this field were analyzed by bibliometric software (VOSviewer and Bibliometricx). Results: 255 original research articles and 204 reviews were included in the analysis. The articles in this field that can be retrieved in WOSCC were first published in 2004 and increased year by year since then. 2013 is a growth explosion point. China and the United States are the countries with the most contributions, and Harvard University is the affiliation with the most output. Frontiers in Immunology (total citations = 603) is the journal with the most publications and the fastest growth rate. eLife is the journal with the most citations (total citations = 1248). Scher, Jose U. and Taneja, Veena are the most productive and cited authors. The research in this field is mainly distributed in the evidence, mechanism and practical application of GM participating in RA through the analysis of keywords and documents. There is sufficient evidence to prove the close relationship between GM and RA, which lays the foundation for this field. This extended two colorful and tender branches of mechanism research and application exploration, which have made some achievements but still have broad exploration space. Recently, the keywords "metabolites", "metabolomics", "acid", "b cells", "balance", "treg cells", "probiotic supplementation" appeared most frequently, which tells us that research on the mechanism of GM participating in RA and exploration of its application are the hotspots in recent years. Discussion: Taken together, these results provide a data-based and objective introduction to the GM participating in RA, giving readers a valuable reference to help guide future research.


Assuntos
Artrite Reumatoide , Doenças Autoimunes , Microbioma Gastrointestinal , Humanos , Linfócitos B , Bibliometria
6.
Front Pharmacol ; 13: 1027687, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36561345

RESUMO

Objective: Curcumae Rhizoma-Sparganii Rhizoma (CR-SR) is a traditional botanical drug pair that can promote blood circulation, remove blood stasis, and treat tumors in clinics. The aim of the present study was to investigate the therapeutic material basis and potential mechanisms of CR-SR, CR, and SR for the treatment of liver cancer. Method: The chemical profile analyses of CR-SR, CR, and SR were performed by molecular networking and UPLC-LTQ-Orbitrap MSn. The anti-liver cancer activities of CR-SR, CR, and SR were assessed by using a zebrafish xenograft model in vivo for the first time and detected by the HepG2 cell model in vitro. Combining the network analysis and molecular docking, real-time quantitative polymerase chain reaction (RT-qPCR) experiments were undertaken to further explore the mechanisms of CR-SR, CR, and SR for the treatment of liver cancer. Results: In total, 65 components were identified in CR-SR, CR, and SR. Based on the clusters of molecular networking, a total of 12 novel diarylheptanoids were identified from CR-SR and CR. By combining our results with information from the literature, 32 sesquiterpenoids and 21 cyclic dipeptides were identified from CR-SR, CR, and SR. The anti-liver cancer activities were observed in both the drug pair and the single botanical drugs in vitro and in vivo, and the order of activity was CR-SR > CR > SR. They could downregulate the expression of proto-oncogene tyrosine-protein kinase Src (SRC), epidermal growth factor receptor (EGFR), estrogen receptor-α (ESR1), prostaglandin endoperoxide synthase 2 (PTGS2), and amyloid precursor protein (APP). Conclusion: Taken together, the present study provided an experimental basis for the therapeutic material basis and potential molecular mechanisms of CR-SR, CR, and SR. This study provided a novel insight for objective clinical treatment of liver cancer.

7.
J Biochem Mol Toxicol ; 35(6): 1-15, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33788351

RESUMO

Esculentoside A (EsA) is a kind of triterpenoid saponins from the root tuber of Phytolacca acinosa Roxb. It has extensive medicinal activity, such as antibacterial, anti-inflammatory, immune regulation, and cell proliferation inhibition. However, some researches suggested that EsA can cause hepatotoxicity, whose mechanism is not precise. To ensure the safety and reliability in the clinical use of Phytolacca acinosa Roxb., it is necessary to establish a rapid and accurate method to evaluate the toxicity, analyze and verify the toxicity mechanism of EsA. Therefore, this research explored the mechanism of hepatotoxicity induced by EsA in rats and analyzed endogenous metabolites' changes in rat plasma by combining network toxicology with non-targeted metabolomics. We obtained 58 critical targets of EsA induced hepatotoxicity in rats based on the strategy of network toxicology, including albumin, mitogen-activated protein kinase 1, Caspase-3, etc. Many important pathways were obtained by Kyoto Encyclopedia of Genes and Genomes enrichment analysis, such as HIF-1 signaling pathway, TNF signaling pathway, IL-17 signaling pathway, and other concerning pathways. Sixteen biomarkers, including 5-hydroxykynurenamine, N-acetylserotonin, palmitic acid, etc., were screened from rat plasma using Ultra-performance liquid chromatography coupled with quadrupole time of flight mass spectrometry (UPLC-Q-TOF/MS), mainly involve Glycerophospholipid metabolism, Tryptophan metabolism, and other metabolic pathways. Further analysis showed that EsA may induce liver injury by activating oxidative stress and energy metabolism disorders, triggering inflammation and apoptosis.


Assuntos
Bases de Dados de Ácidos Nucleicos , Redes e Vias Metabólicas , Metabolômica , Ácido Oleanólico/análogos & derivados , Saponinas/toxicidade , Animais , Doença Hepática Induzida por Substâncias e Drogas/genética , Doença Hepática Induzida por Substâncias e Drogas/patologia , Masculino , Ácido Oleanólico/toxicidade , Ratos , Ratos Wistar
8.
Int J Pharm ; 509(1-2): 296-304, 2016 Jul 25.
Artigo em Inglês | MEDLINE | ID: mdl-27251012

RESUMO

Centella Total Glucosides (CTG),obtained from Centella asiatica (L.), have been shown to possess a multitude of pharmacological activities, however, oral administeration of CTG failed to fulfill their therapeutic potentials due to the low bioavailability. In this study, the author prepared the liposomes encapsulated CTG using the ethanol injection method in order to enhance their intestinal absorption. The average particle size and the polydispersityindex(PDI) of CTG-loaded liposome in a batch are 137.0nm and 0.283, and the CTG-loaded amounts in CTG-loaded liposomes were 0.177mgmL(-1) and the zeta potential of CTG-loaded lipsomes is -21.2mV. The TEM images of CTG-loaded lipsomes showed that CTG-loaded liposomes are round and maintain high structural integrity, and their DSC thermograms indicated that CTG might be incorporated into the aqueous phase of DPPC to become more stable. The everted rat gut sac model was used to study the absorption characteristic of CTG-loaded solution in rat intestines. The cumulative absorption amount (Q) and the cumulative absorption percentage (P%) of asiaticoside in the CTG-loaded liposome was significantly higher than that in CTG (P<0.05), both the steady-state infiltration rate (Jss, µgcm(-2)s(-1)) and the permeability coefficient (Papp, cms(-1)) of asiaticoside in CTG-loaded liposomes were significantly higher than those in CTG (P<0.05), which revealed that the liposomes encapsulated CTG can promote the absorption of asiaticoside in the ileum of the rats by enhancing its transmembrane permeability. The above study will provide the experimental evidence and a reference for the development of the oral dosage forms of Centella total glucosides.


Assuntos
Centella/química , Glucosídeos/química , Absorção Intestinal/efeitos dos fármacos , Lipossomos/química , Triterpenos/química , Triterpenos/metabolismo , Animais , Disponibilidade Biológica , Mucosa Intestinal/metabolismo , Masculino , Tamanho da Partícula , Permeabilidade , Extratos Vegetais , Ratos , Ratos Wistar
9.
Zhongguo Zhong Yao Za Zhi ; 41(10): 1843-1848, 2016 May.
Artigo em Chinês | MEDLINE | ID: mdl-28895330

RESUMO

In order to determine the scientificalness of traditionally processed Whitmania pigra, water extraction method and bionic extraction method were used respectively to extract the anticoagulating active components in W. pigra hanging dry products, talcum powder fried products and wine immersing-baked products. Activated partial thromboplastin time (APTT), prothrombin time (PT), thrombin time (TT), and antithrombin activity were selected as the activity indexes to evaluate the anticoagulant activities of different processed W. pigra. Then the contents of protein in different processed W. pigra were measured by Coomassie brilliant blue method to preliminarily explain the reason of anticoagulant activity changes. When water extraction method was used, the results of APTT, PT, TT and antithrombin activity showed that the anticoagulant activities of W. pigra were decreased both in talcum powder fried products and wine immersing-baked products, and the activity order was as follows: hanging dried products> wine immersing-baked products>talcum powder fried products. This order was same as the protein content order. While when bionic extraction was used, APTT was shortened in talcum powder fried products, but all the other results indicated the anticoagulant activities of W. pigra processed products were increased, and the activity order was as follows: wine immersing-baked products>talcum powder fried products>hanging dry products. As compared with water extraction, the bionic extraction was more similar to the absorption process of W. pigra in human digestive system after oral administration and was more scientific. Therefore, the traditional processing method can not only modify the taste and smell, but also enhance the anticoagulant activity of W. pigra.


Assuntos
Anticoagulantes/farmacologia , Sanguessugas/química , Animais , Antitrombinas/farmacologia , Biônica , Humanos , Tempo de Tromboplastina Parcial , Tempo de Protrombina , Tempo de Trombina , Água
10.
Guang Pu Xue Yu Guang Pu Fen Xi ; 35(9): 2530-5, 2015 Sep.
Artigo em Chinês | MEDLINE | ID: mdl-26669161

RESUMO

Feature selection can improve the interpretation of the modeling variables to a certain extent by selecting variables from the complex spectra backgrounds. However, the improvement of models interpretation does not mean that the modeling variables have the exact physical or chemical significance. In this paper, We explore the relation between the chemical characteristics of target components and the spectrum variables selected with 3 kinds of variables selection methods which are moving window partial least squares regression (mwPLS), synergy interval partial least squares regression (siPLS) and competitive adaptive re-weighted sampling (CARS), and compare the interpretation difference of the variables selected with the above variables selection methods. The results show that the variables selected with mwPLS accord with ν(φ)C=C of liquiritin and δCH3 or δCH2 of glycyrrhizin, which are the obvious spectra differences between the flavonoids and saponins in Radix Glycyrrhizae, and the variables selected with siPLS are the characteristic intervals combinations of the flavonoids or saponins in Radix Glycyrrhizae, which is the combination of ν(ø)C=C, ν(ø)C-O, ν(ø)C-H of flavonoids or the combination of νC-O vC-H, νO-H of saponins while the variables selected with CARS can better accord with most of the characteristic peaks from 1000 to 4000 cm(-1) of liquiritin or glycyrrhizin in Radix Glycyrrhizae, and the predict performance of the infrared quantitative model established on the spectroscopic variables selected with CARS can be improved. Therefore, most of the variables selected with CARS can be interpreted by the characteristic peaks in the infrared characteristic region of the target components, which is beneficial to improve the interpretation of the quantitative model.


Assuntos
Flavanonas/análise , Glucosídeos/análise , Glycyrrhiza/química , Ácido Glicirrízico/análise , Algoritmos , Flavonoides , Análise dos Mínimos Quadrados , Modelos Teóricos , Raízes de Plantas/química , Saponinas , Análise Espectral
11.
Guang Pu Xue Yu Guang Pu Fen Xi ; 34(12): 3267-72, 2014 Dec.
Artigo em Chinês | MEDLINE | ID: mdl-25881421

RESUMO

The appropriate algorithm for calibration set selection was one of the key technologies for a good NIR quantitative model. There are different algorithms for calibration set selection, such as Random Sampling (RS) algorithm, Conventional Selection (CS) algorithm, Kennard-Stone(KS) algorithm and Sample set Portioning based on joint x-y distance (SPXY) algorithm, et al. However, there lack systematic comparisons between two algorithms of the above algorithms. The NIR quantitative models to determine the asiaticoside content in Centella total glucosides were established in the present paper, of which 7 indexes were classified and selected, and the effects of CS algorithm, KS algorithm and SPXY algorithm for calibration set selection on the accuracy and robustness of NIR quantitative models were investigated. The accuracy indexes of NIR quantitative models with calibration set selected by SPXY algorithm were significantly different from that with calibration set selected by CS algorithm or KS algorithm, while the robustness indexes, such as RMSECV and |RMSEP-RMSEC|, were not significantly different. Therefore, SPXY algorithm for calibration set selection could improve the predicative accuracy of NIR quantitative models to determine asiaticoside content in Centella total glucosides, and have no significant effect on the robustness of the models, which provides a reference to determine the appropriate algorithm for calibration set selection when NIR quantitative models are established for the solid system of traditional Chinese medcine.


Assuntos
Centella/química , Glucosídeos/análise , Espectroscopia de Luz Próxima ao Infravermelho , Triterpenos/análise , Algoritmos , Calibragem , Medicamentos de Ervas Chinesas/análise
12.
Se Pu ; 31(8): 813-6, 2013 Aug.
Artigo em Chinês | MEDLINE | ID: mdl-24369620

RESUMO

The preparation of thrombin affinity chromatography media is described in this paper. First, the thrombin affinity chromatography media was prepared through thrombin coupled with cyanogen bromide activated agarose. And then the enzyme activity of thrombin on the coupled media was measured by chromogenic substrate method. The conditions were confirmed based on the enzyme activity of thrombin on the coupled media. The optimum conditions were as follows: the use of Na2CO3-NaHCO3 (containing 0.5 mol/L NaCl) solution of pH 8.3 as the reaction solution, 200 U thrombin per 1 g agarose, and reaction for 10 h at room temperature. The prepared affinity chromatography media had good stability, on which 70.6% of the enzyme activity of thrombin existed after 40 days' storage. The thrombin affinity chromatography media can be widely applied in the screening and purification of thrombin inhibitors in natural products.


Assuntos
Cromatografia de Afinidade , Trombina , Sefarose
13.
Methods Mol Biol ; 970: 489-503, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23283798

RESUMO

As the most popular chiral selectors, ß-cyclodextrin (ß-CD) and its derivatives have been widely used in enantiomer separations. Among functionalized ß-CDs, sulfated ß-CDs are recognized as the most effective chiral additives in capillary electrophoresis (CE) separations. Herein, we describe the preparation of a novel sulfated poly ß-CD-modified silica-based monolithic column and its use for the enantioseparation of some chiral compounds in the capillary electrochromatography (CEC) mode.


Assuntos
Eletrocromatografia Capilar/métodos , Sílica Gel/química , beta-Ciclodextrinas/química , Cromatografia Gasosa , Eletroforese Capilar/métodos , Concentração de Íons de Hidrogênio , Estereoisomerismo , Sulfatos/análise , Sulfatos/química
14.
Anal Sci ; 26(9): 943-7, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-20834124

RESUMO

A sulfated poly ß-cyclodextrin (SPCD) modified silica-based monolithic column was prepared for enantiomeric separation. First, 2-hydroxy-3-allyloxy-propyl-ß-cyclodextrin (allyl-ß-CD) was bonded onto a bifunctional reagent 3-(methacryloxy)propyltriethoxysilane (γ-MAPS) modified silica-based monolith through radical polymerization; the column was then sulfated with chlorosulfonic acid. The SPCD chiral stationary phase resolved the boring problem associated with desalting when sulfated CDs were synthesized to act as chiral additives. The inorganic salt in the column introduced during the sulfating process could be easily removed by washing the column with water for some time. Chiral compounds investigated were successfully resolved into their enantiomers on the SPCD modified monolith in the capillary electrochromatography (CEC) mode. Due to the existence of the -SO(3)H group, electrosmotic flow (EOF) was obviously increased, and all of the separations could be carried out in 20 min with only a minor loss in the column efficiency and resolution.


Assuntos
Eletrocromatografia Capilar , Estereoisomerismo , Ciclodextrinas/química , Concentração de Íons de Hidrogênio , Indicadores e Reagentes , Metacrilatos , Polimerização , Silanos , Dióxido de Silício/química , Dióxido de Silício/metabolismo , Sulfatos/química , Sulfatos/metabolismo , beta-Ciclodextrinas/química , beta-Ciclodextrinas/metabolismo
15.
Anal Sci ; 24(8): 1025-30, 2008 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-18689944

RESUMO

A novel, high-performance wide-bore electrophoresis (WE) system with inner-cooling has been developed. By introducing the mode of a shell and tube heat exchanger into this system to remove Joule heat generated during electrophoresis, it is feasible to extend electrophoresis from the conventional capillary (i.d. <100 microm) to a wide-bore tube (i.d. >1000 microm). The wide tube allows the loading of over 1.0 microL of the sample with an LOD of 3.0 x 10(-4) mg/mL (signal-to-noise ratio, 3:1). Satisfactory separations of model compounds have been achieved on the WE system.


Assuntos
Ácido Benzoico/análise , Eletroforese Capilar/métodos , Ácidos Sulfônicos/análise , Água/química , Ácido Benzoico/química , Temperatura Baixa , Eletroforese Capilar/instrumentação , Temperatura Alta , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Espectrofotometria Ultravioleta/instrumentação , Espectrofotometria Ultravioleta/métodos , Ácidos Sulfônicos/química , Fatores de Tempo
16.
Electrophoresis ; 29(4): 863-70, 2008 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-18213599

RESUMO

A model mixture of six aromatic acids has been separated using a laboratory-made wide-bore electrophoretic device with aminopropyl-modified nanoparticles used as pseudostationary phase. Optimization of preparation of nanoparticles by an electrospray (ES) method is described. With the optimized electrophoretic method, 30 mmol/L acetate running buffer, pH 4.5, containing 1.0 mg/mL of nanoparticles as an additive was used, and 3.0 kV applied potential, improved resolution was achieved. The average theoretical plate number obtained was above 5.0 x 10(4) theoretical plates per meter with the highest value achieved in certain runs exceeding 1.0 x 10(5) theoretical plates per meter, which was better than previously reported results (approximately 6.7 x 10(4) theoretical plates per meter). Furthermore, repeatabilities of 2, 6.5, and 6% were obtained for the migration time, peak areas, and peak height, respectively. Additionally, sample capacity and sensitivity were improved by hundredfold using the novel wide-bore electrophoresis system compared to traditional CE.


Assuntos
Eletroforese Capilar/métodos , Nanopartículas/química , Compostos Orgânicos/análise , Soluções Tampão
17.
Electrophoresis ; 28(11): 1674-80, 2007 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-17480039

RESUMO

A new wide-bore electrophoresis (WE) system adopting an inner cooling device was set up to perform electrochromatography. In this system, a quartz tube of 1.2 mm inner diameter was used as the separation channel. The Joule heat generated during electrophoresis was removed timely through the outer surface of the quartz tube and a cooling capillary inserted into the quartz tube. A proper coolant passed through the cooling capillary to further improve the cooling efficiency. In the primary research, a polyacrylamide monolithic column was successfully prepared in this quartz tube. Then it was evaluated in the electrochromatographic mode. An electric field strength as high as 625 V/cm can be applied to this system without obvious deviation of the current from the linear curve of the Ohm plot. Sample volume as high as 1 microL was injected into the WE system and reasonable efficiency was obtained for separation of the test compounds.


Assuntos
Eletrocromatografia Capilar/instrumentação , Benzenossulfonatos/isolamento & purificação , Eletro-Osmose , Corantes de Alimentos/isolamento & purificação , Reprodutibilidade dos Testes , Reologia
18.
Electrophoresis ; 27(17): 3363-72, 2006 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-16944466

RESUMO

A silica-based CEC monolithic column with mixed modes of RP and weak anion-exchange (WAX) was successfully prepared by using the sol-gel technique at mild temperature. The synthesizing procedure was optimized by changing the ratios of tetraethoxysilane (TEOS), aminopropyltriethoxysilane (APTES), and octyltriethoxysilane (C(8)-TEOS) in the mixture. While serving as WAX group, the amino group dominated the charge on the surface of the capillary column and generated an EOF from cathode to anode at low pH. At pH above 7.5, a cathodic EOF was observed due to the full ionization of silanol group and the suppression in the ionization of amino group. The morphology of monolithic columns was examined by SEM, and the performance of column was evaluated in detail by separating different kinds of compounds. As expected, the monolithic column exhibited RP chromatographic behavior for neutral solutes. Fast and efficient separation of six aromatic acids was obtained using acidic mobile phase with column efficiency up to 160,000 plates/m. Symmetrical peaks can be obtained for aromatic amines because positively charged amino groups on the surface can effectively minimize the adsorption of positively charged analytes to the stationary phase.


Assuntos
Cromatografia Capilar Eletrocinética Micelar/instrumentação , Acetonitrilas , Benzoatos/isolamento & purificação , Cromatografia Capilar Eletrocinética Micelar/métodos , Hidrocarbonetos Aromáticos/isolamento & purificação , Troca Iônica , Microscopia Eletrônica de Varredura , Transição de Fase , Propilaminas , Silanos/química , Dióxido de Silício
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