Nutrigenomics represents a shift of nutrition research from epidemiology and physiology to molecular biology and genetics. Nutrigenomics seeks to understand nutrition influences on homeostasis, the mechanism of genetic predispositions for diseases, to identify the genes influencing risk of diet related diseases. This review presents some in vitro models applicable in nutrigenomic studies, and discuses the use of animal models, their advantages and limitations and relevance for human situation. In vitro and in vivo models are suitable for performance of DNA microarrays, proteomic and transcriptomic analyses. In vitro models (intracellular organelles and suborganellar compartments, cell cultures, or tissue samples/cultures) give insight in metabolic pathways and responses to test stimuli on cellular and molecular levels. Animal models allow evaluation of the biological significance of the effects recorded in vitro and testing of the hypothesis on how a specific factor affects specific species under specific circumstances. Therefore, the evaluation of the data in relation to human organism should be done carefully, considering the species differences. The use of in vitro and in vivo models is likely to continue as the effects of nutrition on health and disease cannot be fully explained without understanding of nutrients action at nuclear level and their role in the intra-and intercellular signal transduction. Through advances in cell and molecular biology (including genomic and proteomic), the use of these models should become more predictively accurate. However, this predictive value relies on an underpinning knowledge of the advantages and limitations of the model in nutrigenomic research as in other fields of biomedical research.

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A new method for the determination of ascorbic, dehydroascorbic and 2.3-diketogulonic acids in animal tissues, blood and urine is described. The material for analysis is homogenized in the presence of stannous chloride in trichloracetic acid and the extract is divided into three aliquots: in one part the ascorbic acid is converted into dehydroascorbic acid by oxidation with bromine water, in the second part the original content of dehydroascorbic and diketogulonic acids is stabilized by the addition of thiourea and in the third part dehydroascorbic acid is reduced to ascorbic acid by thioglycolic acid. Reaction with 2.4-dinitrophenylhydrazine produces a mixture of osazones, from which the bis-hydrazone of diketogulonic acid is isolated by thin-layer chromatography on Silicagel (solvent, ethyl aeetate-chloroform-. acetic acid 50:50:5 v/v). The amount of bis-hydrazone is determined photometrically at 502 nm after dissolution in ethyl-acetate-toluene(1:3 v/v). The content of ascorbic, dehydroascorbic and diketogulonic acids is calculated by comparison of the results from the three aliquots of the extract. The described method is more specific and more sensitive than the former colorimetric methods and is suitable for the isolation and evaluation of small amounts of ascorbic, dehydroascorbic and diketogulonic acids labelled with carbon 14 C. The most commonly used method for the simultaneous content of dehydroascorbic and diketogulonic acids in estimation of the content of ascorbic acid and its meta-the animal tissues and blood, for which the colorimetric bolites in animal material is based on the reaction of the method is not sensitive enough. oxidized form of ascorbic acid and diketogulonic acid The Chromatographie isolation of the osazones of dehywith 2.4-dinitrophenylhydrazine and the photometric droascorbic and diketogulonic acids on thin layers or evaluation of the resulting osazone dissolved in mineral on paper, which have already been used successfully on acid (1). In the simultaneous estimation of all of these plant and animal material (3, 4), increases the specificity substances advantage is taken of the reduction of the of the method and at the same time enables the treatdehydroascorbic acid to ascorbic acid, which does not ment of greater volumes of extracts with a low conreact with the phenylhydrazine reagent. In the difleren-centration of the studied substances than in the method tial method according to ROE and coworkers (2), before of direct colorimetry. Our method of independent the addition of dinitrophenylhydrazine two aliquots of estimation of ascorbic acid and its metabolits is based on the sample are subjected to the action of the oxidizing the method of ROE and coworkers (2) which we have or reducing agent, changing the ascorbic acid to its modified and linked to the isolation of the bis-2.4-oxidized form, and the dehydroascorbic acid to ascorbic dinitrophenylhydrazone of diketogulonic acid on a thin acid. To the third part of the sample the reagent is layer of Silicagel. Its advantage is a gr...

Nowadays, a great attention is paid to the biological activity of plant polyphenols and their potential importance for the human health. Therefore knowledge regarding the dietary intake of polyphenols and their particular subclasses has gained interest. In this report, the results of a pilot study evaluating the average polyphenol content in the Czech diet have been presented.Knowledge of the average intake of plant polyphenols is an important contribution to the evaluation of the dietary pattern from the aspect of its health impact.An annual average consumption of the main foods of plant origin (a total of 80 commodities) was estimated, using data from the Czech annual statistical report, in the entire Czech population in 2013. These values (kg/y) were multiplied with the contents of plant polyphenols in the same items as presented in the in the database Phenol Explorer.The average intake of plant polyphenols was 426 mg/d. The prevailing polyphenols were chlorogenic acid, 82 mg/d (most important sources were potatoes, coffee, plums), followed by apigeninfl avone, 79 mg/d (wheat), heneicosylresorcinol, 38 mg/d (wheat), ferrulic acid, 17 mg/d (wheat) and anthocyanin malvidin, 13 mg/d (red wine). These values are below the intake of polyphenols in the most EU countries.These differences refl ect -inter alia -the fact that beer having low content of polyphenols is a dominant commodity in Czech dietary pattern while fruit and vegetables as well as teas and coffee consumption is relatively low.

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