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A novel method for determination of methylamines and methylamine-N-oxides in fine particles using solid phase extraction (SPE) coupled with ion chromatography (IC) was developed. The experimental conditions including solid phase extraction and chromatographic condition were optimized. The quartz filter loaded with particulate matter (PM) samples was ultrasonically extracted with 20 mL of methanol and water (1:3,V/V) mixture and the extraction process repeated for another 2 times. After the extraction, a total of 60 mL of extraction solvent was dropped into the extraction equipment in solid phase column. The Agilent AccuBond C18was chosen for enriching the methylamine,dimethylamine,trimethylamine and trimethylamine-N-oxide in fine particles. Under the optimum conditions, the target species on Agilent Accu Bond C18were washed by 0. 5 mL of acetonitrile solution and then concentrated into a constant volume (2 mL) before injecting into IC for analysis. A 250 mm×4 mm id PRP X-200 column was used for the separation of analytes at the temperature of 25oC. The mobile phase was a mixture of acetonitrile solution (3%, V/V) and nitric acid (5 mmol/L) with the flow rate being kept at 1 mL/min. The four aliphatic amine species were fully resolved and the separations were completed within 30 min. The linearity of the four compounds ranged from 0.45 to 1000 μg/kg with the precisions of 2%-4% and the detection limits of 0.002-0.003 μg/m3. The recoveries of four aliphatic amine species in real environmental samples were higher than 90%. This method was successfully applied to the analysis of real fine particle samples collected at Beijing. The concentrations of trimethylamine and methylamine-N-oxides were in the range of 0.01-0.08 μg/m3and 0.02-0.14 μg/m3for Beijing dust and haze samples,respectively.
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Introducción: la composición química de las especies vegetales está sujeta a cambios, dependiendo, entre otros factores, de la localización geográfica. Moringa oleífera Lam., que crece en Machala, Ecuador, puede diferir de especies de otras regiones geográficas. Objetivo: realizar un estudio farmacognóstico preliminar del tallo y raíz (corteza y pulpa) de la planta M. oleífera cultivada en las áreas de la Unidad Académica de Ciencias Agropecuarias, de la Universidad Técnica de Machala. Métodos: se desarrolla el control de la calidad de la droga cruda según la metodología establecida por la Organización Mundial de la Salud, mediante determinación de la humedad residual, el porciento de cenizas y el porciento de sustancias solubles en el tallo y la raíz. Se cuantificaron algunos metales mediante espectrometría de emisión óptica con plasma acoplado inductivamente. El estudio químico preliminar se efectuó a través de ensayos de tamizaje fitoquímico y mediante cromatografía en capa delgada. Resultados: la humedad residual para ambos órganos y los valores de cenizas obtenidos para la raíz se encuentran dentro de los límites establecidos. Las cenizas totales para el tallo resultaron elevadas. La determinación de metales descartó la presencia de metales tóxicos en los órganos estudiados. Los valores de sustancias solubles indicaron mayor poder extractivo para el agua. La evaluación mediante tamizaje fitoquímico sugirió triterpenos y esteroides, azúcares reductores, alcaloides, flavonoides, aminoácidos y saponinas, en los extractos de la raíz. En el tallo se detectaron, además, catequinas, mucílagos y compuestos fenólicos, no así flavonoides. La cromatografía en capa delgada sugirió la existencia de alcaloides derivados de la fenilmetilamina. Conclusiones: el estudio permitió establecer parámetros de calidad de la droga cruda para la especie estudiada; sugerir, en principio, semejanzas en composición química de la planta analizada con otras de orígenes geográficos diferentes, y comprobar la ausencia de metales tóxicos en los órganos estudiados(AU)
Introduction: The chemical composition of plant species is subject to changes which depend, among other factors, on their geographic location. The Moringa oleifera Lam. growing in Machala, Ecuador, may differ from species from other geographic regions. Objective: Conduct a preliminary pharmacognostic study of the stem and root (bark and pulp) of the plant M. oleifera grown in areas from the Agricultural Sciences Academic Unit of the Technical University of Machala. Methods: Quality control was performed of the crude drug following the methodology set up by the World Health Organization to determine residual humidity, percentage of ashes and percentage of soluble substances in the stem and the root. Several metals were quantified by inductively coupled plasma atomic emission spectroscopy. The preliminary chemical study was conducted by phytochemical screening testing and thin layer chromatography. Results: Both the residual humidity for both organs and the ash values obtained for the root are within the limits established. Total ashes for the stem were high. Metal determination discarded the presence of toxic metals in the organs studied. Values for soluble substances awarded a greater extraction capacity to water. Phytochemical screening pointed to the presence of triterpenes and steroids, reducing sugars, alkaloids, flavonoids, amino acids and saponins in root extracts. The stem was found to also contain catechins, mucilages and phenolic compounds, but not flavonoids. Thin layer chromatography pointed to the presence of alkaloids derived from phenyl methylamine. Conclusions: The study made it possible to set up crude drug quality parameters for the study species, make preliminary suggestions about similarities between the chemical composition of the plant analyzed and other plants of different geographic origin, and verify the absence of toxic metals in the organs studied(AU)
Subject(s)
Humans , Pharmacognosy , Benzylamines/antagonists & inhibitors , Chromatography, Thin Layer/methods , Moringa oleifera/toxicity , Ecuador/ethnologyABSTRACT
A novel ionization enhancer, methylamine formate, was proposed for improving the detection sensitivity of triglyceride in edible oil by reversed phase liquid chromatography electrospray ionization mass spectrometry (LC-ESI-MS).The commonly used isopropanol-acetonitrile-methanol-water and isopropanol-acetonitrile were selected as the mobile phase.By using a reversed phase C18 column, and taking the corn oil in isopropyl alcohol as sample solution, we compared methylamine formate with ammonium formate, as ionization enhancers, for their effect on the detection sensitivity of triglyceride by LC-ESI-MS after screening other different ionization enhancers, such as formic acid, acetic acid, ammonium formate, ammonium acetate, butyl formate, dibutylamine formate, triethylamine formate, diethylamine formate, methylamine formate, and ethylamine formate.The result indicated that, by using methylamine formate, the mass spectral peak response and the signal to noise ratio for trilinoleic glyceride component were 5 times higher than that of ammonium formate.The effect of the concentration of methylamine formate ionization enhancer, the flow rate of the mobile phase and the flow rate of nebulizing gas on the detection of methylamine formate were investigated.The concentration of triglyceride components in corn oil starting to form aggregates was similar in different mobile phases in the electrospray process according to measurement of the relationship between corn oil concentrations and the total ion chromatogram peak area of triglyceride.In particular, the peak area of trilinolein was linear with its concentration in the range of 7×10-7-2×10-4 mol/L (R2=0.9997), but increased slower in the higher concentration range.According to the experimental data, the mechanism for improvement of detection sensitivity of methylamine formate was suggested as that the addition of methylamine mono-charged ions with hydrophobic groups had lower solvation energy, which made the enriched addition ions easily evaporation from the droplet surface, thus improving the electrospray ionization efficiency.This method provided an effective way to improve the detection sensitivity of triglyceride in edible oil by LC-ESI-MS.
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[ ABSTRACT] AIM:To observe the effect of the metabolites generated from oxidative deamination of methylamine ( MA) or benzylamine ( BZA ) catalyzed by semicarbazide-sensitive amine oxidase ( SSAO ) on 3T3-L1 adipocytes. METHODS:3T3-L1 preadipocytes were induced to differentiation.SSAO activity was determined by high performance liquid chromatography ( HPLC) at different differentiation time points.MTT assay was applied to detect cell vitality after exposure to different concentrations of MA or BZA.Fluorescence probe DCFH-DA was used to determine the production of reactive oxygen species after incubation of 3T3-L1 adipocytes with MA or BZA.After exposure to 0.5 mmol/L MA or BZA for 4 h, malondialdehyde ( MDA) , total superoxide dismutase ( T-SOD) and glutathione ( GSH) in the adipocytes or prea-dipocytes were measured.RESULTS:SSAO activity increased with the increase in the differentiation days, and reached a maximum at the 8th day.Incubation of the cells with different concentrations of MA or BZA for 4 h did not significantly de-creased the cell vitality (P>0.05).After exposure to 0.5 mmol/L MA or BZA, the reactive oxygen species in adipocytes significantly increased, and were about 3 to 4 times as compared with control group (P0.05 ) .CONCLUSION: MA or BZA induces oxidative stress in the mature adipocytes, which might result from the deamination products catalyzed by SSAO.
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OBJECTIVE: To observe the effect of a new compound methylamine irisolidone on cardiac function in rats with experiment myocardial infarction. METHODS: The male Wistar rats were randomly divided into 6 groups: control group, ischemia model group, methylamine irisolidone preconditioning group, pretreated with different dosages of methylamine irisolidone (200,100,50 mg · kg-1, respectively) and 200 mg · kg-1 puerain(positive control). Coronary artery ligation was used to induce the acute myocardial ischemia model. After 30 d administration of methylamine irisolidone, the heart function parameters,including heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), left ventricular systolic pressure (LVSP), maximal velocity of increase and decrease of left ventriclar pressure (dp/dtmax), were analyzed and myocardial histology was analyzed by hematoxylin-eosin staining. RESULTS: Compared with model group, methylamine irisolidone could improve the heart function of rats in AMI injury, increased the systolic pressure and diastolic pressure, decreased the heart rate(P < 0.01). The myocardial ultrastructure injury was alleviate. CONCLUSION: Methylamine irisolidone had cardioprotective effects on acute myocardial ischemia. The mechanism may be related to slow down heart rate, prolong diastolic, so that an increase in the endocardial blood supply.
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AIM To study whether chronic administration of methylamine may induce elevation of semicarbazide-sensitive amine oxidase (SSAO) activity and initiate the injury of cardiovascular endothelium. METHODS New Zealand rabbits were treated with methylamine hydrochloride (100 mg·kg-1) by ig, once a day for 6 months. The rabbits were weighed every other week and the dosage was adjusted according to the body weight. The number of circulating endothelial cells (CEC) in the arterial blood, nitric oxide (NO) concentration in the serum and ultrastructure of endothelial cells of aorta were assessed. The plasma SSAO activity and formaldehyde concentration were assessed by liquid chromatography. RESULTS The number of CEC, NO concentration, levels of SSAO activity and formaldehyde concentration in the methylamine group were increased significantly, compared with the control group. Ultrastructure of endothelial cells in the methylamine group showed inordinate morphological changes (multiple intranuclear inclusions, karyopyknosis and karyorrhexis). CONCLUSIONChronic administration of methylamine can induce the elevation of SSAO activity and initiate the injury of cardiovascular endothelium.