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Study on the interaction of chemopreventive compounds and food born carcinogens with cytochrome P450 enzymes
Brabencová, Eliška ; Hodek, Petr (advisor) ; Koblihová, Jitka (referee)
The use of food supplements containing natural chemopreventive compounds increased in recent years. Some of the most popular chemopreventive compounds are flavonoids. Due to their natural origin, flavonoids are generally accepted as safe compounds. They exert antioxidant, anti-cancer and anti-inflammatory properties. However, flavonoids should be considered as foreign compounds (xenobiotics). Flavonoids interact with many enzymes, among the most important belong cytochromes P450 (CYPs), key enzymes of the first phase of biotransformation of xenobiotics (e.g. drugs, carcinogens). CYPs catalyze reactions leading mainly to detoxification of xenobiotics. However, some CYPs are involved in the activation of carcinogens, particularly CYP1A1 and CYP1A2 activate e.g. heterocyclic amines. Flavonoids might enhance the activation of carcinogens via induction of these CYPs or stimulation of their activities and hence, increase the risk of a cancer development. The thesis is focused on the influence of flavonoids and food carcinogens on the induction and activity of CYP1A1 and CYP1A2 in liver and small intestine of rats. For the purpose of this study, the small intestine was dissected into three parts: proximal (nearest to stomach), middle and distal. Western blotting was used for the evaluation of CYP...
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Study of cytochrome P450 intreaction with dietary carcinogens
Brabencová, Eliška ; Hodek, Petr (advisor) ; Burdová, Kamila (referee)
Humans are exposed to various carcinogens during their life. One of the main sources of carcinogens is a human diet which plays an important role in the cancer development. This bachelor thesis deals with carcinogens that are formed during a technological food processing or cooking of food - polycyclic aromatic hydrocarbons, heterocyclic amines and nitrosamines, then carcinogens produced by fungi - mycotoxins, and carcinogens that are produced by plants - safrole, estragole and pyrrolizidine alkaloids. Among numerous enzymes involved in metabolism of carcinogens, cytochromes P450 belong to the most important ones. These enzymes constitute a superfamily of haem-thiolate proteins, which is significantly involved in the metabolism of many foreign compounds (e.g. carcinogens, drugs, pollutants). Cytochromes P450 catalyze mainly reactions leading to detoxification of harmful compounds. Besides these reactions, the metabolic activation of compounds to more toxic products may occur. Cytochromes P450 play an important role in the activation of carcinogens to reactive electrophiles causing DNA damage. The subject of this bachelor thesis is to show mechanisms of metabolic activation of carcinogens. Key words: cytochromes P450, carcinogenesis, food carcinogens (In Czech)
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Schopnost spotřebitelů reagovat na cenové slevy rychloobrátkového zboží
Brabencova, Eliska ; Král, Petr (advisor) ; Lhotáková, Markéta (referee)
Main goal of this Master's thesis was to evaluate how price reductions influence consumers' likelihood to purchase FMCG products in connection to brand loyalty. Czech customers are characterized by high sensitivity to sales promotions. This thesis is focused on analysis of price discounts of shampoos in the Czech Republic. Leaflets of main retailers selling drugstore products were researched in order to describe the frequency and discount depth of shampoos. Customers' behaviour while buying shampoos and their attitude towards price discounts of shampoos were examined through a questionnaire. Main hypotheses that shampoos are discounted very frequently and of significant depth were confirmed. To conclude, customers' likelihood to buy shampoos increases heavily with discounted prices and some of the customers even believe that it is not worth buying shampoos for full prices.
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