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1.
Shokuhin Eiseigaku Zasshi ; 49(5): 339-46, 2008.
Artigo em Japonês | MEDLINE | ID: mdl-19029785

RESUMO

An extraction and analytical method was developed for determination of the content and profiles of anthocyanins in commercial dietary supplements containing blueberry extract. Dietary supplements were refluxed with hydrochloric acid-methanol solution, and spectrophotometric assay was performed to evaluate the total anthocyanidin content in extracted solutions as delphinidin, which is one of the anthocyanidins in blueberry extract. Twenty compounds (15 anthocyanins and 5 anthocyanidins) in extracted solutions were separated by HPLC analysis with gradient elution using formic acid and methanol-acetonitrile as the mobile phase, and each peak was confirmed by LC/MS analysis. The proposed method was applied to 25 kinds of commercial dietary supplements, and one supplement whose profile was different from that of the fresh bilberry extract was found.


Assuntos
Antocianinas/análise , Mirtilos Azuis (Planta) , Suplementos Nutricionais/análise , Cromatografia Líquida de Alta Pressão , Cromatografia Líquida , Análise de Alimentos/métodos , Espectrometria de Massas
2.
Biol Pharm Bull ; 31(3): 357-62, 2008 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-18310892

RESUMO

Aromatase, a key steroidogenic enzyme that catalyses the conversion of androgens to estrogens, present a target for endocrine disrupting chemicals. However, little is known about the effect of pollutants on aromatase enzymes. In this study, we first optimized a non-radioisotope aromatase assay using rat ovarian microsomes in vitro and measuring the estrone level with an enzyme-linked immunosorbent assay (EIA method). The sensitivity of the EIA method was about ten times as high as that of the radioisotope (RI) method. A significant positive correlation was indicated between EIA and RI method. We used this EIA assay system to investigate the effects of aromatase activity on 45 chemicals that had previously been reported to act as endocrine disruptors or to have the possibility of having such an effect. Six of the chemicals, rose bengal, erythrosine, phloxine, allura red, gallic acid, and tributyltin, inhibited aromatase activity. The inhibitory effect of rose bengal was the strongest (IC50=2.4 x 10(-8) M), and its strength of inhibition was about 100 times that of a known aromatase inhibitor, 4-hydroxy-androstenedione (IC50=2.6 x 10(-6) M) but was about 1/25 that of fadrazole (IC50=1.0 x 10(-9) M). It is thought that this EIA method would be useful for measuring the aromatase activity of microstructures.


Assuntos
Aromatase/metabolismo , Técnicas Biossensoriais/métodos , Disruptores Endócrinos/toxicidade , Estrona/análise , Microssomos/enzimologia , Ovário/enzimologia , Animais , Disruptores Endócrinos/química , Ensaio de Imunoadsorção Enzimática , Feminino , Ratos , Sensibilidade e Especificidade
3.
J Chromatogr A ; 1154(1-2): 423-8, 2007 Jun 22.
Artigo em Inglês | MEDLINE | ID: mdl-17433340

RESUMO

A method for the determination of cyclamate in food was developed using solid-phase extraction (SPE) and capillary electrophoresis (CE) with indirect ultraviolet (UV) detection. A 5-10 g sample in 0.1 mol/L hydrochloric acid was homogenized and made up to a volume of 50 mL with 0.1 mol/L hydrochloric acid. After the sample was centrifuged, 25 mL of supernatant was loaded into an Oasis HLB SPE cartridge. The cartridge was washed with 2 mL of demineralized water followed by 2 mL of 50% aqueous methanol, and cyclamate was eluted with 4.5 mL of 50% aqueous methanol. The eluate was added to a solution of sodium propionate (internal standard) for CE analysis. The cyclamate in the eluate was electrophoresed on a fused-silica capillary using 1 mmol/L hexadecyltrimethylammonium bromide and 10 mmol/L potassium sorbate as a running buffer. Detection and reference wavelengths of cyclamate determined with a UV detector were 300 and 254 nm, respectively. The calibration curves for cyclamate showed good linearity in the range of 2-1000 microg/mL and the limits of detection in beverage, fruit in syrup, jam, pickles and confectionary are sample dependent and ranged from 5-10 microg/g. The recovery of cyclamate added at a level of 200 microg/g to various kinds of foods was 93.3-108.3% and the relative standard deviation was less than 4.9% (n=3). A number of commercial samples were analyzed using the proposed method. Cyclamate was detected in one waume, two pickles, and two sunflower seeds. The quantitative values determined with CE correlated to those from high-performance liquid chromatography (HPLC) (the detected values of cyclamate in a sunflower seed measured by CE and HPLC were 3.40 g/kg and 3.51 g/kg, respectively). This analytical method for cyclamate using CE is especially suitable for use in the field.


Assuntos
Ciclamatos/análise , Eletroforese Capilar/métodos , Análise de Alimentos/métodos , Cromatografia Líquida de Alta Pressão , Aditivos Alimentares , Reprodutibilidade dos Testes , Extração em Fase Sólida , Incerteza
4.
J AOAC Int ; 89(4): 1042-7, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-16915843

RESUMO

A method for the determination of Cinchona extract (whose main components are the alkaloids cinchonine, cinchonidine, quinidine, and quinine) in beverages by liquid chromatography was developed. A beverage with an alcohol content of more than 10% was loaded onto an OASIS HLB solid-phase extraction cartridge, after it was adjusted to pH 10 with 28% ammonium hydroxide. Other beverages were centrifuged at 4000 rpm for 5 min, and the supernatant was loaded onto the cartridge. The cartridge was washed with water followed by 15% methanol, and the Cinchona alkaloids were eluted with methanol. The Cinchona alkaloids in the eluate were chromatographed on an L-column ODS (4.6 mm id x 150 mm) with methanol and 20 mmol/L potassium dihydrogen phosphate (3 + 7) as the mobile phase. Cinchona alkaloids were monitored with an ultraviolet (UV) detector at 230 nm, and with a fluorescence detector at 405 nm for cinchonine and cinchonidine and 450 nm for quinidine and quinine (excitation at 235 nm). The calibration curves for Cinchona alkaloids with the UV detector showed good linearity in the range of 2-400 microg/mL. The detection limit of each Cinchona alkaloid, taken to be the concentration at which the absorption spectrum could be identified, was 2 microg/mL. The recovery of Cinchona alkaloids added at a level of 100 microg/g to various kinds of beverages was 87.6-96.5%, and the coefficients of variation were less than 3.3%. A number of beverage samples, some labeled to contain bitter substances, were analyzed by the proposed method. Quinine was detected in 2 samples of carbonated beverage.


Assuntos
Bebidas , Técnicas de Química Analítica/métodos , Cromatografia Líquida/métodos , Alcaloides de Cinchona/análise , Análise de Alimentos/métodos , Calibragem , Concentração de Íons de Hidrogênio , Fosfatos/análise , Compostos de Potássio/análise , Quinina/análise , Padrões de Referência , Espectrofotometria , Fatores de Tempo , Raios Ultravioleta
5.
Shokuhin Eiseigaku Zasshi ; 46(5): 228-33, 2005 Oct.
Artigo em Japonês | MEDLINE | ID: mdl-16305179

RESUMO

Suitable liquid chromatography/mass spetrometry (LC/MS) conditions were examined for Amaranth, Red 2G (R2G), Azo Rubine (Azo), Fast Red E (FRE) and Brilliant Blue FCF, which were detected in Akasu, a red vinegar made in Hong Kong from sake lees, on both thin layer chromatography (TLC) and photodiode array high-performance liquid chromatography (PDA-HPLC). Molecular-related ions for each dye were detected with excellent sensitivity by LC/MS using electro-spray ionization with negative ion mode, capillary voltage 3.00 kV, cone voltage 50 V and desolvation temperature 400 degrees C. LC/MS analysis of refined Akasu under these conditions enabled us to obtain clear mass spectra of R2G, Azo and FRE, which were present at trace levels in the Akasu. The results were consistent with those from TLC and PDA-HPLC. These experiments suggested that LC/MS analysis is applicable for confirmation of dyes in food.


Assuntos
Ácido Acético/análise , Cromatografia Líquida , Corantes/análise , Espectrometria de Massas , Corante Amaranto/análise , Cromatografia em Camada Delgada
6.
Shokuhin Eiseigaku Zasshi ; 46(3): 93-8, 2005 Jun.
Artigo em Japonês | MEDLINE | ID: mdl-16042295

RESUMO

Hajikami (ginger pickled in vinegar) is often used as a relish for grilled fish, and it often contains coloring agents. We detected Rose Bengal (R105) and two unknown dyes in some Hajikami by thin layer chromatography. In this study, we tried to characterize these unknown dyes by HPLC with photodiode array detection (PDA-HPLC), liquid chromatography/mass spectrometry (LC/MS) and nuclear magnetic resonance (NMR). PDA-HPLC analysis showed that the spectra of the unknown dyes resembled that of R105, suggesting the molecular structures of these two dyes are similar to that of R105. Furthermore, LC/MS analysis suggested that the these dyes are R105 in which one or two iodines are replaced by hydrogen. Finally, the two dyes were determined by 1H-NMR and 13C-NMR to be 4,5,6,7-tetrachloro-3',6'-dihydroxy-2',7'-diiodo spiro[isobenzofuran- 1 (3H),9'-[9H]xanthen]-3-one disodium salt and 4,5,6,7-tetrachloro-3',6'-dihydroxy-2',7'-diiodo spiro[isobenzofuran-1(3H),9'[9H]xanthen]-3-one disodium salt.


Assuntos
Corantes/química , Análise de Alimentos , Gengibre/química , Cromatografia Líquida de Alta Pressão , Cromatografia Líquida , Corantes/isolamento & purificação , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Rosa Bengala/análise
7.
Shokuhin Eiseigaku Zasshi ; 45(3): 150-5, 2004 Jun.
Artigo em Japonês | MEDLINE | ID: mdl-15468935

RESUMO

A method for the determination of 12 synthetic food dyes (Amaranth, Erythrosine, Allura Red AC, New Coccine, Phloxine, Rose Bengal, Acid Red, Tartrazine, Sunset Yellow FCF, Fast Green FCF, Brilliant Blue FCF, Indigo Carmine) in food was developed using capillary electrophoresis (CE) with photodiode array detection. The dyes were extracted with water and 0.5% ammonia-ethanol (1:1) mixture, and cleaned up using solid-phase extraction (Sep-Pak Plus tC18). The dyes were eluted with methanol from the cartridge. The dyes were separated by CE on a bubble cell fused-silica capillary (72 cm to the detector, 75 microm i.d.) using 20% acetonitrile in a mixture of 10 mmol/L potassium phosphate, monobasic and 5 mmol/L sodium carbonate (pH 10.0) as the running buffer. Identifications of the dyes were performed on the basis of the migration time and the absorbance spectrum of each peak. The coefficients of variation of the migration times and the peak areas were 0.28-0.62% and 1.84-4.30%, respectively (n = 5). The identification limits using the absorbance spectra of the dyes were 10 microg/mL for Brilliant Blue FCF and Fast Green FCF, and 5 microg/mL for the other 10 dyes. The recoveries of the 12 dyes from pickles, soft drinks and candies at the level of 10 microg/g were 70.0-101.5%. The method was applied to the analysis of dyes in foods. The dyes detected by CE were in agreement with those detected by paper chromatography.


Assuntos
Eletroforese Capilar/métodos , Análise de Alimentos/métodos , Corantes de Alimentos/análise , Alcatrões/análise , Corantes de Alimentos/isolamento & purificação , Reprodutibilidade dos Testes
8.
J AOAC Int ; 86(2): 215-21, 2003.
Artigo em Inglês | MEDLINE | ID: mdl-12723908

RESUMO

A 3-step extraction method was developed for the simultaneous determination of 11 dyes and their aluminum lakes in drugs. The dyes were first extracted with warm water (approximately 60 degrees C) and were cleaned up by solid-phase extraction with a tC18 cartridge. Aluminum lake dyes that remained in the precipitate were extracted with 0.02M NaOH. Aluminum in the dye lakes was reextracted into the organic layer with acetylacetone-butyl acetate (1 + 9, v/v), as an acetylacetone chelate, and was quantified by atomic absorption spectrometry. The dye portions of the aluminum lakes remained in the aqueous layer and were cleaned up in the same way as the dyes. The dyes and the dye portions of the aluminum lakes were quantified by ion-pair liquid chromatography with a photodiode array detector within 20 min. The recoveries of dyes from drug fortified at 10 microg of each dye per pill were 87.0-102.2%, and the recoveries of dyes from drugs fortified at 50 microg of each dye lake per pill were 82.9-101.6%, except for recoveries of indigo carmine. In 40 ethical and over-the-counter drugs, dyes that were not indicated in the package insert information for drugs were detected in 5 samples. The highest amount of dye found in a drug was 1169.5 microg erythrosine, which was detected in a capsule of antibiotic. Aluminum lake dyes were detected in 8 samples of various dosage forms.


Assuntos
Alumínio/análise , Corantes/análise , Preparações Farmacêuticas/análise , Cápsulas , Cromatografia Líquida , Indicadores e Reagentes , Japão , Solventes , Espectrofotometria Atômica , Comprimidos
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