Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 3 de 3
Filtrar
Mais filtros

Base de dados
Tipo de documento
Intervalo de ano de publicação
1.
J Agric Food Chem ; 47(10): 4189-94, 1999 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-10552789

RESUMO

Commercially prepared marigold flower (Tagetes erecta) extract was saponified and analyzed for carotenoid composition. HPLC analyses were performed on two normal-phase columns (beta-Cyclobond and silica) and on a C(30) reversed-phase column. The extract contained 93% utilizable pigments (detected at 450 nm), consisting of all-trans and cis isomers of zeaxanthin (5%), all-trans and cis isomers of lutein, and lutein esters (88%). All were identified by chromatographic retention, UV-visible spectra, and positive ion electrospray mass spectrometry in comparison to authentic standards. Contrary to previous findings, insignificant levels (<0.3%) of lutein oxidation products were detected in the saponified extract. This compositional determination is important for the application of marigold extract in nutritional supplements and increases its value as a poultry feed colorant because it contains more biologically useful lutein compounds than previously believed.


Assuntos
Carotenoides/análise , Extratos Vegetais/química , Ração Animal , Animais , Cromatografia Líquida de Alta Pressão , Suplementos Nutricionais , Corantes de Alimentos , Humanos , Valor Nutritivo , Aves Domésticas
2.
Analyst ; 122(9): 977-80, 1997 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-9374027

RESUMO

A procedure was developed for the detection and determination of bixin and norbixin in human plasma by reversed-phase HPLC with a sensitivity limit of 5 micrograms l-1. A group of seven volunteers ingested a single dose of 1 ml of a commercial Annatto Food Color (16 mg of cis-bixin in soybean oil). The presence of bixin (cis and trans) and norbixin (cis and trans) was demonstrated in the plasma at average levels of 11.6, 10.1, 2.8 and 0 micrograms l-1 of bixin and 48, 58, 53 and 29 micrograms l-1 of norbixin after 2, 4, 6 and 8 h, respectively. Considerable individual variations were observed. Complete plasma clearance generally occurred for bixin by 8 h and for norbixin by 24 h after ingestion of cis-bixin.


Assuntos
Carotenoides/análise , Corantes de Alimentos/análise , Absorção Intestinal , Carotenoides/sangue , Carotenoides/metabolismo , Humanos , Plantas Comestíveis , Estereoisomerismo
3.
Biomed Chromatogr ; 5(1): 3-7, 1991 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-2032020

RESUMO

The optical purity of scopolamine derived from Datura sanguinea was determined using coupled column chromatography. A C18 column was used to separate scopolamine from the additional alkaloids and other biological material present in the vegetal extract. The C18 column was coupled through a six-port switching valve to two beta-cyclodextrin columns in series which were used to resolve the scopolamine enantiomers. A single acetylated beta-cyclodextrin column gives equivalent results to the native cyclodextrin columns because of slightly higher enantioselectivity for scopolamine. A multistep extraction procedure is used to isolate scopolamine from the vegetal material. 4-6% of the scopolamine in the final extract was found to be the d enantiomer. Sample extracts as well as commercial scopolamine hydrobromide were treated under various conditions commonly encountered during typical commercial extraction procedures and analyzed in order to determine if the d enantiomer was present in the original material or if it was produced during the extraction process and, if so, determine which step and conditions contribute to racemization. Both the salt and the extract were found to be susceptible to racemization under basic conditions (greater than or equal to pH 9) although the extract appeared to be more susceptible than the salt. Tropic acid formed from the hydrolysis of scopolamine seemed to be completely racemized even though the remaining scopolamine was only partially racemized. Within experimental error, no d enantiomer was found in the original fresh plant material.


Assuntos
Cromatografia/métodos , Extratos Vegetais/análise , Escopolamina/isolamento & purificação , beta-Ciclodextrinas , Acetilação , Ciclodextrinas , Concentração de Íons de Hidrogênio , Escopolamina/química , Estereoisomerismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA