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1.
Rev. farm. bioquim. Univ. Säo Paulo ; 29(1): 17-24, jan.-jun. 1993. ilus, tab
Artigo em Português | LILACS | ID: lil-128649

RESUMO

Varios metodos analiticos foram desenvolvidos com a finalidade de obter procedimentos simples, rapidos e economicos para a determinacao de pro-vitamina A em alimentos. Neste trabalho tres desses metodos foram avaliados: os de COST91,IVACG e RODRIGUEZ-AMAYA et alii simplificado. Os alimentos escolhidos foram couve, cenoura, mamao e tomate, devido as suas caracteristicas distintas quanto a composicao de pro-vitamina A. As principais deficiencias apresentadas pelo metodo recomendado por COST91 foram a extracao incompleta e a saponificacao drastica. Outra grande falha do metodo foi a nao separacao entre alfa e beta-caroteno, e a nao consideracao da alfa e beta-criptoxantina e do beta-caroteno. Para o metodo apresentado pelo IVACG, a extracao foi insuficiente apenas para couve. Esse metodo demonstrou ser mais versatil que COST92, pois permitiu a separacao das diferentes pro-vitaminas. Dos procedimentos de saponificacao sugeridos, a saponificacao a frio confirmou ser a tecnica mais aconselhavel. O metodo de RODRIGUEZ-AMAYA et alii simplificado mostrou ser o mais indicado, principalmente pela sua simplicidade e exatidao


Assuntos
Carotenoides/análise , Frutas/análise , Métodos , Plantas/análise , Vitamina A/análise , Análise de Alimentos , Plantas Comestíveis/análise
2.
West Indian med. j ; 41(1): 23-6, Mar. 1992.
Artigo em Inglês | LILACS | ID: lil-107504

RESUMO

Subacute intraperitoneal administration of the lipid portion of the unripe ackee arillus, referred to as "ackee oil", resulted in marked neutropenia (p<0.001) and increase in platelets (p<0.01) without anaemia, in rats. Blood urea, sodium amd aspartate aminotransferase levels were significantly decreased but glucose and bilirubin levels were similar to those of controls. The lungs showed areas of petechial haemorrhaghes and a dose-related perivascular and peribronchial mononuclear cell infiltration. The pulmonary toxicity may be interpreted as a hypersensitive reaction to ackee oil. Further research is in progress on the neutropenic effects of ackee oil.


Assuntos
Plantas Comestíveis/análise , Neutropenia/induzido quimicamente
5.
Am J Clin Nutr ; 54(4): 615-7, 1991 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-1654738

RESUMO

The complexity of plant foods high in dietary fiber poses new challenges to clinical investigators and leads to many study-design dilemmas. There are basic differences in studying purified polymers, highly concentrated but not purified fibers, and diets high in high-fiber whole foods. The fibrils of the plant cell wall are most likely altered when prepared as a pure chemical entity, and when fiber concentrates (eg, wheat bran) are used, the method of preparation may alter the composition of the final product. Whole-plant, high-fiber foods are complex storehouses of a diversity of polymers, including resistant starch, and of bioactive compounds. Furthermore, the addition of a reasonable amount of high-fiber food to the diet not only adds dietary fiber but many digestible, caloric macronutrients that alter the entire diet composition. These problems and dilemmas are reviewed.


Assuntos
Fibras na Dieta/química , Análise de Alimentos , Plantas Comestíveis/análise , Parede Celular/química , Fibras na Dieta/administração & dosagem , Ingestão de Alimentos , Humanos , Polímeros , Sementes/análise , Amido/administração & dosagem , Amido/metabolismo
7.
J Assoc Off Anal Chem ; 74(2): 384-8, 1991.
Artigo em Inglês | MEDLINE | ID: mdl-1904852

RESUMO

The ethylenebisdithiocarbamate (EBDC) fungicide, nabam, was determined in several crop matrixes using liquid chromatography with postcolumn reaction detection. After separation by micellar liquid chromatography, nabam (EBDC sodium salt) was acid hydrolyzed to ethylenediamine and fluorigenically labeled with o-phthalaldehyde-mercaptoethanol (OPA-MERC). Standard curves were linear from the detection limit of ca 1 ng to 1000 ng. Nabam was recovered in high yield (89 plus or minus 7.7%) over a range of concentrations (0.1 to 20 ppm) from fortified samples of papaya, lettuce, cucumber, spinach, and applesauce using a simple extraction method. Efforts to convert the more popular EBDC fungicides, maneb and mancozeb, to nabam are discussed.


Assuntos
Etilenobis (ditiocarbamatos)/análise , Fungicidas Industriais/análise , Plantas Comestíveis/análise , Cetilpiridínio , Cromatografia Líquida/métodos , Ácido Edético , Frutas/análise , Hidrólise , Mercaptoetanol , Verduras/análise , o-Ftalaldeído
8.
Food Chem Toxicol ; 29(3): 167-72, 1991 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-2032658

RESUMO

An analytical procedure previously developed for the trace determination of nitrosamides was applied to a screening of nitrosated foodstuffs for nitrosoureas. Different types of foodstuffs were nitrosated both under chemical conditions using a high nitrite concentration, and under simulated gastric conditions. Methylating activity corresponding to N-nitroso-N-methylurea (MNU) was detected in most samples. Under chemical conditions, the yields spanned several orders of magnitude with processed fish and meat products being at the top, and plant products at the bottom of the scale. After nitrosation under simulated gastric conditions, the range of MNU activity was significantly smaller. No correlation exists between the yields determined under chemical and simulated gastric conditions.


Assuntos
Análise de Alimentos , Compostos Nitrosos/análise , Animais , Cromatografia Gasosa , Produtos Pesqueiros/análise , Suco Gástrico/metabolismo , Concentração de Íons de Hidrogênio , Produtos da Carne/análise , Metilnitrosoureia/análise , Nitrosação , Compostos de Nitrosoureia/análise , Plantas Comestíveis/análise
9.
Agric Biol Chem ; 55(2): 449-53, 1991 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-1368695

RESUMO

Rubusoside (the beta-D-glucosyl ester of 13-O-beta-D-glucosyl-steviol), which is the major sweet principle of leaves of Rubus suavissimus S. Lee, was subjected to 1,4-alpha-transglucosylation by the cyclodextringlucanotransferase-starch system (the CGTase system). The tri- and tetra-glucosylated products were isolated together with the mono- and di-glucosylated products, which had already been isolated. A prominent increase in intensity of the sweetness was observed for the compounds which were di- and tri-glucosylated at the 13-O-glucosyl moiety. This result further substantiated the structure-sweetness relationship for 1,4-alpha-glucosylated compounds of steviol-glycosides reported previously. For protection of the 19-COO-glucosyl moiety against glucosylation by the CGTase system, the 4-hydroxyl group of the 19-COO-glucosyl moiety was beta-galactosylated by the beta-galactosidase-lactose system. This galactosylated compound was subjected to a regio-selective glucosylation of the 13-O-glucosyl moiety by the CGTase system, which was followed by enzymic elimination of the galactosyl group to furnish an exclusive preparation of the improved sweeteners just mentioned.


Assuntos
Diterpenos de Caurano , Diterpenos/química , Glucosídeos/química , Sequência de Carboidratos , Diterpenos/isolamento & purificação , Glucosídeos/isolamento & purificação , Glicosilação , Dados de Sequência Molecular , Estrutura Molecular , Plantas Comestíveis/análise , Edulcorantes/química , Edulcorantes/isolamento & purificação
11.
Biomed Environ Mass Spectrom ; 19(7): 415-9, 1990 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-2205314

RESUMO

With the aid of a new chiral derivatizing reagent and a sensitive and specific assay using capillary gas chromatography/negative ion chemical ionization mass spectrometry, the proportions of R and S enantiomers of 1-methyl-1,2,3,4-tetrahydroisoquinoline (1MeTIQ) in mammalian tissues and foods were studied. R- and S-1MeTIQ enantiomers derivatized with a chiral derivatizing reagent, perfluoro-2-propoxypropionylchloride, were clearly separated. The ratio of enantiomers was R/S = 0.24, 0.55 and 0.60 in wine, cocoa and mouse brain. S-1MeTIQ predominated in all samples. This result suggested that 1MeTIQ could be formed at least partially through an enzymatic mechanism.


Assuntos
Química Encefálica , Cacau/análise , Isoquinolinas/análise , Plantas Comestíveis/análise , Tetra-Hidroisoquinolinas , Vinho/análise , Animais , Cromatografia Gasosa , Isoquinolinas/síntese química , Masculino , Espectrometria de Massas , Camundongos , Camundongos Endogâmicos C57BL , Sensibilidade e Especificidade , Estereoisomerismo
13.
Neurology ; 40(5): 767-72, 1990 May.
Artigo em Inglês | MEDLINE | ID: mdl-2330104

RESUMO

We conducted an investigation of the levels of the neurotoxin 2-amino-3-(methylamino)-propanoic acid (BMAA) in cycad flour. Analysis of 30 flour samples processed from the endosperm of Cycas circinalis seeds collected on Guam indicated that more than 87% of the total BMAA content was removed during processing. Furthermore, in 1/2 the samples almost all (greater than 99%) of the total BMAA was removed. We found no significant regional differences in the BMAA content of flour prepared from cycad seeds collected from several villages on Guam. Testing of different samples prepared by the same Chamorro woman over 2 years suggests that the washing procedure probably varies in thoroughness from preparation to preparation but is routinely efficient in removing at least 85% of the total BMAA from all batches. Analysis of a flour sample that had undergone only 24 hours of soaking indicated that this single wash removed 90% of the total BMAA. We conclude that processed cycad flour as prepared by the Chamorros of Guam and Rota contains extremely low levels of BMAA, which are in the order of only 0.005% by weight (mean values for all samples). Thus, even when cycad flour is a dietary staple and eaten regularly, it seems unlikely that these low levels could cause the delayed and widespread neurofibrillary degeneration of nerve cells observed in amyotrophic lateral sclerosis and the parkinsonism-dementia complex of Guam (ALS-PD).


Assuntos
Diamino Aminoácidos/análise , Esclerose Amiotrófica Lateral/induzido quimicamente , Farinha/análise , Neurotoxinas/análise , Doença de Parkinson Secundária/induzido quimicamente , Diamino Aminoácidos/efeitos adversos , Guam , Humanos , Plantas Comestíveis/análise , Sementes , Estatística como Assunto
14.
Carcinogenesis ; 11(2): 349-53, 1990 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-2302762

RESUMO

Based upon the US National Toxicology Program (NTP) rodent carcinogenicity data base, CASE, an artificial intelligence structure-activity evaluation method, predicts that a large proportion of natural pesticides present in edible plants are rodent carcinogens.


Assuntos
Carcinógenos Ambientais/toxicidade , Praguicidas/toxicidade , Plantas Comestíveis/análise , Animais , Camundongos , Neoplasias Experimentais/induzido quimicamente , Controle Biológico de Vetores , Ratos , Relação Estrutura-Atividade
15.
Sci Total Environ ; 91: 87-96, 1990 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-2321001

RESUMO

An attempt was made to estimate the daily intake of 137Cs by moose during different months and seasons, and to compare this result with the 137Cs activity concentration in moose muscles. Plants representative of moose diet in central Sweden showed a high 137Cs activity concentration compared with plants from agricultural systems, and there appears to be very slow reduction of 137Cs activity concentration in these forest plants. It seems that the daily intake of 137Cs was low during the summer, but it exhibited a peak in the autumn, which corresponds to the 137Cs activity concentration in moose muscles and also coincides with the hunting season.


Assuntos
Radioisótopos de Césio/análise , Cervos/metabolismo , Contaminação Radioativa de Alimentos/análise , Plantas Comestíveis/análise , Animais , Músculos/análise , Estações do Ano , Suécia
17.
Basic Life Sci ; 52: 155-66, 1990.
Artigo em Inglês | MEDLINE | ID: mdl-2183767

RESUMO

A continuing study of chemopreventive agents has focused on three categories of naturally-occurring compounds that inhibit carcinogen activation and are effective in preventing carcinogen-induced neoplasia when administered at short time intervals prior to carcinogen challenge. The three are: aromatic isothiocyanates found in cruciferous vegetables, monoterpenes from citrus fruits and caraway seed oils, and organosulfur compounds occurring in Allium species. The short time-interval effects could be significant in terms of their impact on responses of humans to carcinogen exposures. The capacity of sodium cyanate, cruciferous vegetables, orange oil, benzyl isothiocyanate, and D-limonene to act as both blocking and suppressing agents has been discussed. Two possible mechanisms for this multiphase activity were presented. The first is that these inhibitory substances activate a complex integrated defense mechanism against toxic compounds which entails both blocking and suppressing components. The blocking component is the initial line of defense, and the suppressing component constitutes a "fail-safe" backup to assure that if any of the toxic material attacks cellular constituents, its effects will be nullified. The second possible mechanism considered is that the inhibitors, because of high reactivity, have multiple biological effects that are separate and not part of a single, coordinated response. Inhibitors that have both blocking and suppressing effects could be particularly useful as chemopreventive agents.


Assuntos
Neoplasias/prevenção & controle , Extratos Vegetais/farmacologia , Animais , Biotransformação/efeitos dos fármacos , Carcinógenos/farmacocinética , Depressão Química , Feminino , Inativação Metabólica , Camundongos , Neoplasias Experimentais/prevenção & controle , Plantas Comestíveis/análise , Ratos
19.
Acta Vet Scand ; 31(3): 257-65, 1990.
Artigo em Inglês | MEDLINE | ID: mdl-2080770

RESUMO

The most important grass species on the ovine white-liver disease (OWLD) pastures (S) were Poa spp., Agropyron repens and Lolium perenne, while the control pastures (H), where lambs grew well, consisted of Poa spp., Festuca rubra and Agrostis tenuis. The soil was more acidic on the H pastures as compared with the S pastures. OWLD grass (S grass) contained marginal to deficient amounts of cobalt during the first 2 months of grazing. During 2 years out of 3, the average Co content was slightly lower in the S grass as compared with the content in the H grass. The lowest average grass Co was, however, found during one year in the H grass, in spite of the fact that the H lambs also this year grew well, and were 13 kg heavier than the S lambs after 3 1/2 months on pasture. Results thus indicate that the H lambs some years were subclinically Co deficient, without developing clinical symptoms or OWLD, and that factors other than marginal/deficient grass Co are of importance as to whether OWLD will develop or not. S grass differed from H grass by having significantly lower copper, molybdenum, manganese and zinc content, lower protein N/amid N ratios and higher aluminium and iron contents. According to the results, marginal to deficient grass Co is essential for development of OWLD, but cofactors play a part.


Assuntos
Hepatopatias/veterinária , Plantas Comestíveis/análise , Plantas Tóxicas/análise , Poaceae , Doenças dos Ovinos/etiologia , Alcaloides/análise , Animais , Alcaloides Indólicos , Hepatopatias/etiologia , Ovinos , Oligoelementos/análise
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