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1.
Ultrason Sonochem ; 69: 105258, 2020 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-32702637

RESUMEN

O/W nanoemulsions are isotropic colloidal systems constituted of oil droplets dispersed in continuous aqueous media and stabilised by surfactant molecules. Nanoemulsions hold applications in more widespread technological domains, more crucially in the pharmaceutical industry. Innovative nanoemulsion-based drug delivery system has been suggested as a powerful alternative strategy through the useful means of encapsulating, protecting, and delivering the poorly water-soluble bioactive components. Consequently, there is a need to generate an emulsion with small and consistent droplets. Diverse studies acknowledged that ultrasonic cavitation is a feasible and energy-efficient method in making pharmaceutical-grade nanoemulsions. This method offers more notable improvements in terms of stability with a lower Ostwald ripening rate. Meanwhile, a microstructured reactor, for instance, microchannel, has further been realised as an innovative technology that facilitates combinatorial approaches with the acceleration of reaction, analysis, and measurement. The recent breakthrough that has been achieved is the controlled generation of fine and monodispersed multiple emulsions through microstructured reactors. The small inner dimensions of microchannel display properties such as short diffusion paths and high specific interfacial areas, which increase the mass and heat transfer rates. Hence, the combination of ultrasonic cavitation with microstructures (microchannel) provides process intensification of creating a smaller monodispersed nanoemulsion system. This investigation is vital as it will then facilitate the creation of new nanoemulsion based drug delivery system continuously. Following this, the fabrication of microchannel and setup of its combination with ultrasound was conducted in the generation of O/W nanoemulsion, as well as optimisation to analyse the effect of varied operating parameters on the mean droplet diameter and dispersity of the nanoemulsion generated, besides monitoring the stability of the nanoemulsion. Scanning transmission electron microscopy (STEM) images were also carried out for the droplet size measurements. In short, the outcomes of this study are encouraging, which necessitates further investigations to be carried out to advance a better understanding of coupling microchannel with ultrasound to produce pharmaceutical-grade nanoemulsions.


Asunto(s)
Emulsiones/química , Microquímica/instrumentación , Nanoestructuras/química , Aceite de Palma/química , Ultrasonido/métodos , Agua/química , Hexosas/química , Microquímica/métodos , Sonicación/métodos , Tensoactivos
2.
Artículo en Inglés | MEDLINE | ID: mdl-25906033

RESUMEN

Probe electrospray ionization (PESI) is a recently developed ionization technique based on electrospray ionization (ESI) that generates electrospray from the tip of a solid needle. High tolerance to salts, requirements of a trace amount of sample and direct ambient sampling- are major advantages of PESI compared with conventional ESI. In this report, three pairs of isomeric lignans bearing tetra-hydrofuran with variable conformations from Gymnotheca chinensis were investigated by probe electrospray tandem mass spectrometry (PESI-MS/MS) in the positive ion mode. The diagnostic characteristics of these compounds were obtained and the isomers could be successfully distinguished by comparison with their breakdown curves, even though the isomers differed only in the conformation of some groups of the isomer pairs. This report provides a rapid and reliable method for the identification of trace amounts of isomeric lignans by PESI-MS/MS. Furthermore, application of PESI and breakdown curves should have value in mass spectrometry studies of isomeric natural products compounds.


Asunto(s)
Lignanos/análisis , Lignanos/química , Microquímica/métodos , Extractos Vegetales/análisis , Extractos Vegetales/química , Saururaceae/química , Espectrometría de Masa por Ionización de Electrospray/métodos , Estereoisomerismo
3.
Appl Radiat Isot ; 90: 218-24, 2014 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-24814608

RESUMEN

This paper compares trace element concentrations (Ca, K, Sr, Fe, Mn, Zn, Ni, Cu, Co and Cr) in 27 Sudanese medical plants determined in parallel by PIXE and ICP-OES to get information on which technique is preferable at different matrices and element concentrations. PIXE correlates well to ICP-OES for Sr, Mn, Ca, K, Zn and Fe determinations. ICP-OES seems to be the superior technique over PIXE when measuring low concentrated elements (chromium, cobalt, nickel and copper) in the medicinal plants.


Asunto(s)
Metales/análisis , Plantas Medicinales/química , Espectrometría por Rayos X/métodos , Espectrofotometría Atómica/métodos , Oligoelementos/análisis , Metales/química , Microquímica/métodos , Sudán , Oligoelementos/química
4.
J Agric Food Chem ; 60(18): 4508-13, 2012 May 09.
Artículo en Inglés | MEDLINE | ID: mdl-22524670

RESUMEN

A rapid and direct low micromolar ¹H NMR method for the simultaneous identification and quantification of hydrogen peroxide and phenolic compounds in plant extracts was developed. The method is based on the highly deshielded ¹H NMR signal of H2O2 at ∼10.30 ppm in DMSO-d6 and the combined use of picric acid and low temperature, near the freezing point of the solution, in order to achieve the minimum proton exchange rate. Line widths of H2O2 below 3.8 Hz were obtained for several Greek oregano extracts which resulted in a detection limit of 0.7 µmol L⁻¹. Application of an array of NMR experiments, including 2D ¹H-¹³C HMBC, spiking of the samples with H2O2, and variable temperature experiments, resulted in the unequivocal assignment of H2O2 precluding any confusion with interferences from intrinsic phenolics in the extract.


Asunto(s)
Peróxido de Hidrógeno/análisis , Microquímica/métodos , Fenoles/análisis , Extractos Vegetales/química , Cinamatos/análisis , Flavonoides/análisis , Espectroscopía de Resonancia Magnética/métodos , Monoterpenos/análisis , Origanum/química , Componentes Aéreos de las Plantas/química , Factores de Tiempo
5.
Anal Sci ; 27(11): 1149-55, 2011.
Artículo en Inglés | MEDLINE | ID: mdl-22076344

RESUMEN

A certified reference material (CRM) for trace elements in tea leaves has been developed in National Metrology Institute of Japan (NMIJ). The CRM was provided as a dry powder (<90 µm) after frozen pulverization of washed and dried fresh tea leaves from a tea plant farm in Shizuoka Prefecture, Japan. Characterization of the property value for each element was carried out exclusively by NMIJ with at least two independent analytical methods, including inductively coupled plasma mass spectrometry (ICP-MS), high-resolution (HR-) ICP-MS, isotope-dilution (ID-) ICP-MS, inductively coupled plasma optical emission spectrometry (ICP-OES), graphite-furnace atomic-absorption spectrometry (GF-AAS) and flame atomic-absorption spectrometry (FAAS). Property values were provided for 19 elements (Ca, K, Mg, P, Al, B, Ba, Cd, Cu, Fe, Li, Mn, Na, Ni, Pb, Rb, Sr, Zn and Co) and informative values for 18 elements (Ti, V, Cr, Y, and all of the lanthanides, except for Pm whose isotopes are exclusively radioactive). The concentration ranges of property values and informative values were from 1.59% (mass) of K to 0.0139 mg kg(-1) of Cd and from 0.6 mg kg(-1) of Ti to 0.0014 mg kg(-1) of Lu, respectively. Combined relatively standard uncertainties of the property values were estimated by considering the uncertainties of the homogeneity, analytical methods, characterization, calibration standard, and dry-mass correction factor. The range of the relative combined standard uncertainties was from 1.5% of Mg and K to 4.1% of Cd.


Asunto(s)
Agencias Gubernamentales/normas , Metales/análisis , Microquímica/métodos , Té/química , Calibración , Japón , Espectrometría de Masas/métodos , Metales/química , Hojas de la Planta/química , Espectrofotometría Atómica/métodos
6.
J Oleo Sci ; 60(7): 355-62, 2011.
Artículo en Inglés | MEDLINE | ID: mdl-21701099

RESUMEN

The aim of this work was to investigate the effect of sucrose on the phase behavior of vegetable oil/polyoxyethylene sorbitan monooleate (MOPS, Tween 80) and decaglycerol monolaurilester (DGML)/aqueous solution systems to establish low-energy emulsification methods for preparing nano-emulsions suitable for food uses. Phase diagrams were constructed to elucidate the optimal process for preparing the nano-emulsions. It was found that nano-emulsions were obtained when the composition was altered to either cross the sponge phase (L(3)) or lamellar phase (La) in the vegetable oil/MOPS/aqueous solution system or vegetable oil/DGML/aqueous solution system, respectively. The average droplet sizes in the former and latter emulsions were 0.203 µm and 0.165 µm, respectively. The addition of sucrose changed the hexagonal phase in the vegetable oil/MOPS/aqueous solution system into the sponge phase. As a result, the sponge region in the vegetable oil/MOPS/sucrose aqueous solution system occupied a larger area than that in the vegetable oil/MOPS/water system. In contrast, sucrose had no effect on the area of the La region in the vegetable oil/DGML/aqueous solution system. However, the addition of sucrose decreased the amount of emulsifier required to prepare nano-emulsions in both the vegetable oil/MOPS and DGML/aqueous solution systems. Sucrose was confirmed to facilitate the preparation of nano-emulsions in both systems.


Asunto(s)
Emulsionantes/síntesis química , Emulsiones/química , Tecnología de Alimentos/métodos , Emulsionantes/química , Glicéridos/química , Hexosas/química , Cristales Líquidos/química , Microquímica/métodos , Aceites de Plantas/química , Polisorbatos/química , Soluciones/química , Sacarosa/química , Agua/química
7.
Artículo en Inglés | MEDLINE | ID: mdl-21416414

RESUMEN

The commercial success of synthetic phosphodiesterase-5 (PDE-5) inhibitors (viz. sildenafil, vardenafil and tadalafil) for erectile dysfunction (ED) has led to their widespread use as adulterants in dietary supplements (DSs). Reports on adulteration by ED drugs or their analogues in DSs suggest they may cause a serious threat to human health. The problem is becoming more complex as hidden and structurally modified analogues are continuously being reported. To analyse known drugs and their analogues, three commonly used PDE-5 inhibitors, naturally existing icariin and yohimbin, and their 19 analogues were analyzed in this study. They were identified using ion-spray liquid chromatography/tandem mass spectrometry (LC/MS/MS) using multiple reaction monitoring (MRM). This MRM procedure gave a limit of detection of less than 0.02 ng ml(-1) for the 24 compounds, selectivity of fragmentation using MRM for 2.5 - 8.5 min in a single run and peak height repeatability of coefficient of variation of 3.9 - 31.8%. An IDA method using the MRM scans to detect the presence of known analytes was set up and added to a built-in library for screening for PDE-5 inhibitors. These MRM experiments were used to trigger product ion scans using a hybrid quadrupole-linear ion trap instrument. The product ion scan was compared and confirmed by a library search of MS/MS spectra acquired from a reference standard. To search for new analogues of PDE-5 inhibitors, a precursor ion scan of an expected ion m/z 283, which was one of the mass fragments from the analogues of sildenafil or vardenafil, was performed and fragmentation of the precursor ion, by combining a precursor ion scan with automatic confirmation using EPI spectra, was acquired. Of the 37 DSs tested, two were eventually found to be adulterated with yohimbin and vardenafil, respectively. The approach proposed in this study would be valuable in characterizing chemical constituents of drug residues and their analogues with identical chemical substructures from complex natural and synthetic sources in DSs using an information-dependent acquisition-enhanced product ion (IDA-EPI) scan.


Asunto(s)
Suplementos Dietéticos/análisis , Inhibidores de Fosfodiesterasa 5/análisis , Cromatografía Líquida de Alta Presión , Imidazoles/análisis , Imidazoles/química , Límite de Detección , Microquímica/métodos , Inhibidores de Fosfodiesterasa 5/química , Piperazinas/análisis , Piperazinas/química , Reproducibilidad de los Resultados , Espectrometría de Masa por Ionización de Electrospray , Sulfonas/análisis , Sulfonas/química , Espectrometría de Masas en Tándem , Triazinas/análisis , Triazinas/química , Diclorhidrato de Vardenafil , Yohimbina/análisis , Yohimbina/química
8.
J Pharm Biomed Anal ; 55(1): 48-53, 2011 Apr 28.
Artículo en Inglés | MEDLINE | ID: mdl-21310573

RESUMEN

This work was dedicated to the development of a new micro immobilized enzyme reactor (IMER) by using an in situ procedure. Arginase was covalently immobilized on an ethylenediamine (EDA) monolithic convective interaction media (CIM) disk (12mm × 3mm i.d.) previously derivatized with glutaraldehyde. The activity of this IMER was investigated by inserting this micro-IMER in a HPLC system. The effect of the arginase inhibitors was evaluated by the simultaneous injection of each inhibitor with the nitro guanidino benzene (NGB) substrate. The relative IC50 values were found in agreement with those derived by the conventional spectrometric method. This arginase micro-IMER system was also used to study the effects of plant-derived products on the arginase activity. The pet ether extract from the stem bark of the plant Ficus glomerata Roxob. and the procyanidin oligomers of cocoa and chocolate inhibit the arginase activity. Our results confirmed the direct effect of some plant extracts on the arginase activity and their interest in therapies for treating several NO-dependent smooth disorders.


Asunto(s)
Arginasa/antagonistas & inhibidores , Descubrimiento de Drogas/métodos , Inhibidores Enzimáticos/farmacología , Enzimas Inmovilizadas/antagonistas & inhibidores , Tecnología Farmacéutica , Arginasa/química , Arginasa/metabolismo , Cacao/química , Cromatografía Líquida de Alta Presión , Enzimas Inmovilizadas/metabolismo , Etilenodiaminas/química , Ficus/química , Glutaral/química , Guanidinas/química , Guanidinas/metabolismo , Concentración de Iones de Hidrógeno , Microquímica/métodos , Modelos Moleculares , Estructura Molecular , Nitrobencenos/química , Nitrobencenos/metabolismo , Corteza de la Planta/química , Extractos Vegetales/química , Tallos de la Planta/química , Polímeros/química , Proantocianidinas/farmacología
9.
J Pharm Biomed Anal ; 54(4): 717-21, 2011 Mar 25.
Artículo en Inglés | MEDLINE | ID: mdl-21130592

RESUMEN

The present paper describes a novel, sensitive and selective liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the simultaneous analysis of ganoderic acids C(2), B, A, H, D in Ganoderma lucidum and its related species. Ganoderma samples were prepared using simple ultrasonic extraction. Chromatographic separation was carried out on an Agilent Zorbax XDB C(18) column (250 mm × 4.6 mm i.d., 5µm) with an isocratic mobile phase consisting of acetonitrile, water and formic acid (42:58:0.5, v/v/v). Mass spectrometric detection was achieved by a triple-quadrupole mass spectrometer equipped with an atmospheric pressure chemical ionization (APCI) interface operating in negative and positive ionization mode via a single within-run polarity switching. Quantitation of five ganoderic acids was performed using selective reaction monitoring (SRM) mode. The intra- and inter-day precision was less than 6.2% and the accuracy ranged from 90.0% to 105.7%. The limit of quantification (LOQ) was 20.0-40.0 ng/mL and the limit of detection (LOD) was 3.0-25.0 ng/mL. With this method, low levels of ganoderic acids in the fruiting bodies of Ganoderma sinense and Ganoderma applanatum were accurately quantified for the first time. Importantly, the method allows unequivocal quantification of the five ganoderic acids in the spores and fruiting bodies of Ganoderma lucidum, whereas the previously published methods have lacked the capability. The method presented will be a powerful tool for quality control of Ganoderma lucidum and its related species.


Asunto(s)
Medicamentos Herbarios Chinos/química , Ácidos Heptanoicos/análisis , Lanosterol/análogos & derivados , Reishi/química , Tecnología Farmacéutica , Cromatografía Líquida de Alta Presión , Cuerpos Fructíferos de los Hongos/química , Ganoderma/química , Ácidos Heptanoicos/química , Lanosterol/análisis , Lanosterol/química , Límite de Detección , Microquímica/métodos , Polisacáridos/análisis , Polisacáridos/química , Reproducibilidad de los Resultados , Esporas Fúngicas/química , Esteroles/análisis , Esteroles/química , Espectrometría de Masas en Tándem , Triterpenos/análisis , Triterpenos/química
10.
J Agric Food Chem ; 58(18): 9931-5, 2010 Sep 22.
Artículo en Inglés | MEDLINE | ID: mdl-20806935

RESUMEN

Soluble saccharides are very important metabolites of the life cycle and synthesis of structural polysaccharide components (cellulose, hemicellulose, pectin, etc.) of cell walls. A new method for droplet sampling of saps from tissues of organisms and manipulation routines in capillaries for extraction, derivation, and partitioning were developed for picogram-scale quantitative determination with gas chromatography-mass spectrometry (GC-MS). Five to ten microliters of sap was sampled with a glass capillary containing ribitol (internal standard). Subsequently, the analytes were acetylated with acetic anhydride and catalyzed by 1-methylimidazole. Finally, the soluble saccharides were qualitatively detected with GC-MS SIM (selective ion monitoring) mode. The linear ranges of the method were up to 1×10(-6) mol/L and the theoretically lowest limits of detection (LOD, s/n≥3) were up to 1×10(-9) mol/L. The method is suitable and applicable to analysis of soluble monosaccharides in fresh tissues and other aqueous samples in wide fields of agriculture, food science, biological sciences, and even medical studies.


Asunto(s)
Microquímica/métodos , Monosacáridos/análisis , Oligosacáridos/análisis , Exudados de Plantas/química , Métodos Analíticos de la Preparación de la Muestra , Cromatografía de Gases y Espectrometría de Masas , Monosacáridos/química , Monosacáridos/aislamiento & purificación , Oligosacáridos/química , Oligosacáridos/aislamiento & purificación , Extractos Vegetales/química , Extractos Vegetales/aislamiento & purificación , Solubilidad , Alcoholes del Azúcar/análisis , Alcoholes del Azúcar/química , Alcoholes del Azúcar/aislamiento & purificación
11.
Biol Reprod ; 83(5): 791-8, 2010 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-20668257

RESUMEN

In vitro embryo culture systems promote development at rates lower than in vivo systems. The goal of this project was to discover transcripts that may be responsible for a decrease of embryo competency in blastocyst-stage embryos cultured in vitro. Gilts were artificially inseminated on the first day of estrus, and on Day 2, one oviduct and the tip of a uterine horn were flushed and the recovered embryos were cultured in porcine zygote medium 3 for 4 days. On Day 6, the gilts were euthanized and the contralateral horn was flushed to obtain in vivo derived embryos. Total RNA was extracted from three pools of 10 blastocysts from each treatment. First and second strand cDNA was synthesized and sequenced using Illumina sequencing. The reads generated were aligned to a custom-built database designed to represent the known porcine transcriptome. A total of 1170 database members were different between the two groups (P < 0.05), and 588 of those had at least a 2-fold difference. Eleven transcripts were subjected to real-time PCR that validated the sequencing. There was an overall decrease in inner cell mass (ICM) and trophectodermal (TE) cell numbers in embryos cultured in vitro; however, no difference in the ICM:TE ratio was found. Interestingly, the transcript SLC7A1 was higher in the in vitro cultured group. This difference disappeared after addition of arginine to the 4-day culture. Illumina sequencing and alignment to a custom transcriptome identified a large number of genes that yield clues on ways to manipulate the culture media to mimic the in vivo environment.


Asunto(s)
Blastocisto/metabolismo , Desarrollo Embrionario , Fertilización In Vitro/veterinaria , Regulación del Desarrollo de la Expresión Génica , ARN Mensajero/metabolismo , Sus scrofa/embriología , Crianza de Animales Domésticos/métodos , Animales , Arginina/metabolismo , Blastocisto/citología , Masa Celular Interna del Blastocisto/citología , Transportador de Aminoácidos Catiónicos 1/genética , Transportador de Aminoácidos Catiónicos 1/metabolismo , Recuento de Células/veterinaria , ADN Complementario/química , ADN Complementario/metabolismo , Bases de Datos de Ácidos Nucleicos , Técnicas de Cultivo de Embriones/veterinaria , Femenino , Fertilización In Vitro/métodos , Perfilación de la Expresión Génica/métodos , Perfilación de la Expresión Génica/veterinaria , Microquímica/métodos , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Análisis de Secuencia de ADN/métodos , Análisis de Secuencia de ADN/veterinaria , Sus scrofa/metabolismo , Trofoblastos/citología
12.
Methods Cell Biol ; 95: 331-51, 2010.
Artículo en Inglés | MEDLINE | ID: mdl-20466143

RESUMEN

We developed tubulin purification strategies that allowed sufficient material to be produced for compound-screening projects. Tubulins were polymerized in the presence of compounds using either turbidometric or fluorescence polymerization assays. IC50 and EC50 values were calculated and used to determine ratios between host and target tubulin (TT) (e.g., IC50-neuronal tubulin/IC50-TT). This ratio can be compared between compounds to identify the ones which are most selective for a particular TT. We found ratios for different compounds ranged from 0.16 to 4.0 between neuronal and cancer cell tubulin indicating that the sequence and posttranslational heterogeneity between these tubulins are sufficient to identify selective ligands for the TT. Likewise, compounds compared between neuronal and fungal tubulin had ratios ranging from 0.03 to 0.60, and compounds compared between neuronal to plant tubulin had ratios ranging from 0.03 to 52. Considering these data, we believe cancer cell tubulin-targeted drugs could be obtained with ratios in excess of 20, herbicides with ratios in excess of 200, and fungicides in excess of 200.


Asunto(s)
Evaluación Preclínica de Medicamentos/métodos , Microquímica/métodos , Multimerización de Proteína , Moduladores de Tubulina/análisis , Tubulina (Proteína)/química , Tubulina (Proteína)/metabolismo , Animales , Humanos , Ligandos , Multimerización de Proteína/fisiología , Resultado del Tratamiento , Tubulina (Proteína)/aislamiento & purificación
13.
Amino Acids ; 38(4): 1031-41, 2010 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-19526311

RESUMEN

Thyrotropin-releasing hormone (TRH) is involved in a wide range of biological responses. It has a central role in the endocrine system and regulates several neurobiological activities. In the present study, a rapid, sensitive and selective liquid chromatography-mass spectrometry method for the identification and quantification of TRH has been developed. The methodology takes advantage of the specificity of the selected-ion monitoring acquisition mode with a limit of detection of 1 fmol. Furthermore, the MS/MS fragmentation pattern of TRH has been investigated to develop a selected reaction monitoring (SRM) method that allows the detection of a specific b2 product ion at m/z 249.1, corresponding to the N-terminus dipeptide pyroglutamic acid-histidine. The method has been tested on rat hypothalami to evaluate its suitability for the detection within very complex biological samples.


Asunto(s)
Cromatografía Líquida de Alta Presión , Espectrometría de Masas en Tándem , Hormona Liberadora de Tirotropina/análisis , Aminoácidos/análisis , Animales , Calibración , Cromatografía de Fase Inversa , Dipéptidos/análisis , Dipéptidos/química , Hipotálamo/química , Límite de Detección , Microquímica/métodos , Estructura Molecular , Ácido Pirrolidona Carboxílico/análogos & derivados , Ácido Pirrolidona Carboxílico/análisis , Ácido Pirrolidona Carboxílico/química , Ratas , Reproducibilidad de los Resultados , Espectrometría de Masa por Ionización de Electrospray , Hormona Liberadora de Tirotropina/síntesis química , Hormona Liberadora de Tirotropina/química , Hormona Liberadora de Tirotropina/aislamiento & purificación
14.
Mol Nutr Food Res ; 54(2): 292-300, 2010 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-20013884

RESUMEN

Recently, 1,2-dehydropyrrolizidine alkaloid (PA) ester alkaloids, found predominantly as their N-oxides (PANOs, pyrrolizidine N-oxides), have been reported in both honey and in pollen obtained directly from PA plants and pollen loads collected by bees, raising the possibility of health risks for consumers of these products. We confirm these findings in regard to floral pollen, using pollen collected directly from flowers of the known PA plants Senecio jacobaea, S. vernalis, Echium vulgare and pollinia of Phalaenopsis hybrids, and we extend analyses of 1,2-unsaturated PAs and 1,2-unsaturated PANOs to include bee-pollen products currently being sold in supermarkets and on the Internet as food supplements. PA content of floral pollen ranged from 0.5 to 5 mg/g. The highest values were observed in pollen obtained from Senecio species. Up to 95% of the PAs are found as PANOs. Detailed studies with S. vernalis revealed unique PA patterns in pollen and flowers. While seneciphylline was the most prominent PA in S. vernalis pollen, the flowers were dominated by senecionine. To analyze trace amounts of 1,2-unsaturated PAs in pollen products, our previously elaborated method consisting of strong cation exchange-SPE, two reduction steps followed by silylation and subsequent capillary high-resolution GC-MS using SIM mode was applied. In total, 55 commercially available pollen products were analyzed. Seventeen (31%) samples contained 1,2-unsaturated PAs in the range from 1.08 to 16.35 microg/g, calculated as retronecine equivalents. The 1,2-unsaturated PA content of pollen products is expressed in terms of a single sum parameter and no background information such as foraged plants, pollen analysis, etc. was needed to analyze the samples. The detection limit of overall procedure and the reliable quantitation limit were 0.003 and 0.01 microg/g, respectively.


Asunto(s)
Productos Biológicos/química , Suplementos Dietéticos/análisis , Miel/análisis , Polen/química , Alcaloides de Pirrolicidina/análisis , Métodos Analíticos de la Preparación de la Muestra , Suplementos Dietéticos/normas , Flores/química , Cromatografía de Gases y Espectrometría de Masas , Límite de Detección , Microquímica/métodos , Estructura Molecular , Alcaloides de Pirrolicidina/química , Alcaloides de Pirrolicidina/toxicidad , Reproducibilidad de los Resultados , Especificidad de la Especie
15.
Yao Xue Xue Bao ; 44(6): 640-4, 2009 Jun.
Artículo en Chino | MEDLINE | ID: mdl-19806897

RESUMEN

This study is to investigate the effect of Cordyceps sinensis and its cultured mycelia on growth and metabolism of Escherichia coli, and microcalorimetric method was carried out to evaluate its biological activity. The study will provide the basis for the quality control of Cordyceps sinensis. Experimental result will show the effect of natural Cordyceps sinensis and its cultured mycelia on growth and metabolism of Escherichia coli, with index of P(1max) and effective rate (E) by microcalorimetry, the data of experiment were studied by cluster analysis. The results showed that Cordyceps sinensis and its cultured mycelia not only can promote growth and metabolism of Escherichia coli but also can regulate the balance of intestinal microecology efficiently. When the concentrations of samples > 6.0 mg mL(-1), natural Cordyceps sinensis can promote the growth and metabolism of Escherichia coli efficiently (P < 0.05) compared with the control group, and have better dose-effect relationship with concentration (r > 0.9), its cultured mycelia does not show conspicuous auxoaction (P > 0.05) and have not dose-effect relationship with concentration (r < 0.6); when the concentration of samples < 6.0 mg mL(-1), all samples does not show conspicuous auxoaction (P > 0.05). Natural Cordyceps sinensis and its cultured mycelia can be distinguished by cluster analysis. Microcalorimetry has a good prospect on the quality evaluation of the traditional Chinese medicine.


Asunto(s)
Productos Biológicos/farmacología , Cordyceps , Escherichia coli/efectos de los fármacos , Escherichia coli/crecimiento & desarrollo , Micelio , Calorimetría/métodos , Microquímica/métodos
16.
J Trace Elem Med Biol ; 23(4): 243-50, 2009.
Artículo en Inglés | MEDLINE | ID: mdl-19747619

RESUMEN

The well-known beneficial health effects of Se have demanded the development of rapid and accurate methods for its analysis. A flow injection (FI) method with inductively coupled plasma mass spectrometry (ICP-MS) as a selenium-selective detector was optimized. Flow injection was carried out using a Knauer 1100 smartline inert series liquid chromatograph coupled with a Perkin Elmer DRC II ICP-mass spectrometer. For sample injection a Perkin Elmer electronic valve equipped with a 25microL sample loop was employed. Before measurement, standards or samples were administered with 1microg/L rhodium as internal standard for correction of changes in detector response according to changes in sample electrolyte concentration. The method characterization parameters are: LOD (3sigma criterion): 26ng/L, LOQ (10sigma criterion): 86ng/L, linearity: 0.05->10microg/L, r(2)=0.9999, serial or day-to-day precision at 2microg/L: 4.48% or 5.6%. Accuracy was determined by (a) recovery experiments (CSF spiked with 2microg/L Se); (b) comparison of FI-ICP-MS measurement with graphite furnace atomic absorption (GFAAS) measurements of 1:10 diluted serum samples; (c) Se determination in urine and serum control materials. Recovery (a) was 101.4%, measurement comparison with GFAAS (b) showed 98.8% (5 serum samples, 1:10 diluted in the range of 0.5-1.3microg/L, compared to GFAAS determination, which was set to 100%), and accuracy was 96.8% or 105.6% for the serum or urine control material. Analysis time per sample was short and typically below 2min for the complete measurement, including sample introduction, sample-line purge and quadruplicate Se determination. This method was used to determine Se in cerebrospinal fluid (CSF) and plasma (here parallel to GFAAS) in 35 paired serum and CSF samples. Se determination gave values in the range of 42-130microg/L for serum and 1.63-6.66microg/L for CSF. The median for Se in 35 individual CSF samples was 3.28microg/L, the mean (+/-SD) was 3.67 (1.35)microg/L, whilst for individual serum samples the median was 81microg/L and the mean (+/-SD) was 85 (26)microg/L. When relating the paired Se concentrations of CSF samples to respective serum samples it turned out that Se-CSF (behind blood brain barrier (BBB)) is independent on Se-serum concentration (before BBB).


Asunto(s)
Análisis de Inyección de Flujo/métodos , Espectrometría de Masas/métodos , Microquímica/métodos , Selenio/sangre , Selenio/líquido cefalorraquídeo , Barrera Hematoencefálica/fisiología , Calibración , Humanos , Isótopos , Reproducibilidad de los Resultados , Espectrofotometría Atómica/métodos
17.
Methods Mol Biol ; 581: 281-90, 2009.
Artículo en Inglés | MEDLINE | ID: mdl-19768629

RESUMEN

Biodiesel is produced by reacting vegetable oils or animal fats with alcohol in the presence of an alkaline catalyst. The resulting methyl esters, which are the biodiesel fuel, are separated from the by-product glycerin, and then washed with water and dehydrated to produce fuel that must meet standardized specifications. Degraded oils containing high levels of free fatty acids can also be converted to biodiesel, but pretreatment with acid-catalyzed esterification is required. The resulting fuel is suitable for use as a neat fuel in diesel engines or blended with conventional diesel fuel.


Asunto(s)
Biocombustibles , Biotecnología/métodos , Algoritmos , Biocombustibles/análisis , Biocombustibles/provisión & distribución , Metabolismo Energético , Esterificación/fisiología , Microquímica/métodos , Modelos Biológicos , Aceites de Plantas/química , Aceites de Plantas/metabolismo , Control de Calidad
18.
Ecotoxicol Environ Saf ; 72(1): 128-135, 2009 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-18328562

RESUMEN

A microcalorimetric technique was applied to a series of experiments to follow the toxic effect caused by the trivalent iron on the single and mixed microbes in sterilized soil that was inoculated with the single Bacillus subtilis (B. subtilis) (prokaryotic bacterium), single Candida humicola (C. humicola) (eukaryotic fungus) and the mixed-species. The microbial activity was stimulated by the addition of 5.0mg glucose and 5.0mg ammonium sulfate under a 35% controlled humidity in the studied soil samples of 1.2g. The power-time curves from every experiment were analyzed, and from these analyses characteristic parameters, such as growth rate constant (k) and total thermal effect (Q) which can reflect the biochemical reactions were determined. The mixed-species have moderate tolerance to the iron overload, comparing with single species, and exhibit synergistic interaction in exponential growth phase (0-400.0 microg mL(-1)). Meanwhile, there is no much difference in the thermal effect (Q) per gram soil sample for the single and mixed culture. This also validates that the nutrient substances in natural environment determine the organisms' metabolic activities. Ultraviolet-visible spectrophotometry and dissolved oxygen sensor also were successfully applied to reflect the activities of B. subtilis and C. humicola in the pure culture. The investigation could provide insight into the microbial ecology of bacteria and fungi in ecological niches.


Asunto(s)
Compuestos Férricos/farmacología , Microbiología del Suelo , Suelo/análisis , Bacillus subtilis/efectos de los fármacos , Bacillus subtilis/crecimiento & desarrollo , Calcio/análisis , Calorimetría/métodos , Candida/efectos de los fármacos , Candida/crecimiento & desarrollo , Cloruros , Magnesio/análisis , Microquímica/métodos , Oxígeno/análisis , Fósforo/análisis , Potasio/análisis , Sodio/análisis , Espectrofotometría
19.
Bioanalysis ; 1(7): 1293-305, 2009 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-21083052

RESUMEN

The concept of specifically determining the clinical pharmacokinetics of a compound using a very low nonpharmacologically active dose (microdose) with an abridged safety and chemistry, manufacturing and control package is relatively new. It is not without its controversy and it is still a subject of discussion. Here, the rationale and application of this approach are examined, together with the regulatory and bioanalytical framework. There are two bioanalytical methods commonly used for human microdosing studies: LC-MS/MS and accelerator MS (AMS). Each method has advantages and disadvantages with the choice of instrumentation being closely tied to the primary objective(s) of the study. If a rapid decision is required on the appropriateness of a pharmacokinetic profile or if a choice is needed from a series of compounds, especially before radiolabeled material is available, LC-MS/MS may be preferable. However, if extreme sensitivity is required, data are required on all drug-related material and metabolites, or a simultaneous intravenous microdose is used to determine absolute bioavailability (sometimes referred to as microtracing), AMS becomes the analytical method of choice. Examples are provided of microdosing studies utilizing both of these bioanalytical techniques. It is emphasized that microdosing is only one tool in the drug developer's tool box and it should be used in the context of all available data. However, when used appropriately, microdosing is a valuable tool, bridging between lead optimization and early clinical development.


Asunto(s)
Evaluación Preclínica de Medicamentos/métodos , Microquímica/métodos , Preparaciones Farmacéuticas/análisis , Disponibilidad Biológica , Cromatografía Liquida/instrumentación , Cromatografía Liquida/métodos , Evaluación Preclínica de Medicamentos/instrumentación , Humanos , Espectrometría de Masas/instrumentación , Espectrometría de Masas/métodos , Microquímica/instrumentación , Preparaciones Farmacéuticas/metabolismo , Reproducibilidad de los Resultados , Tamaño de la Muestra , Sensibilidad y Especificidad
20.
Appl Biochem Biotechnol ; 151(2-3): 711-23, 2008 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-18830826

RESUMEN

Feruloyl, chlorogenate esterases, and tannases are enzymes useful in phenolic modifications of pharmaceutical relevance as protectors against several degenerative human diseases. Therefore, there is a growing interest in discovering new sources of these enzymes. However, traditional methods for their activity measurements are time-consuming and poorly adapted for high-throughput screening. In this study, a successful new microplate high-throughput screening method for the simultaneous quantification of all mentioned activities is demonstrated. This method allows the detection of activities as low as 1.7 mU ml(-1). Furthermore, reaction rates increased proportionally with the amount of enzyme added, and no interferences with the other commercial hydrolases tested were found. The utility of the method was demonstrated after simultaneously screening feruloyl, chlorogenate esterase, and tannase activities in solid state fermentation extracts obtained during the kinetics of production of 20 fungal strains. Among these, seven strains were positive for at least one of the esterase activities tested. This result shows the potential for the rapid routine screening assays for multiple samples of moderate low to high enzymatic levels.


Asunto(s)
Hidrolasas de Éster Carboxílico/análisis , Microquímica/métodos , Aspergillus/enzimología , Café/microbiología , Evaluación Preclínica de Medicamentos/métodos , Fermentación
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