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Complexes of zinc salts and flavonoids
Křížová, Tereza ; Roithová, Jana (advisor) ; Volný, Michael (referee)
Modern mass spectrometry (MS) is very well suited for analysis of flavonoids and their complexes. Progress during the last two decades has made MS the most sensitive method for molecular analysis of flavonoids. MS has a potential to provide information on the exact molecular mass, as well as on the structure. Flavonoids are acting as chelating agents on various metal ions. The goal of this study was to discover, which types of ions are formed in solutions of zinc salts and flavonoids by using mass spectrometry attached with electrospray ionization. First, we have studies substructures of flavonoid - resorcin, pyrokatechin a pyron - in order to find out, how individual parts of flavonoid interact with zinc ions.
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Plant alkaloids and their effects on enzymes metabolizing xenobiotics
Višněvská, Kateřina ; Stiborová, Marie (advisor) ; Černá, Věra (referee)
Sanguinarine and chelerythrine are quaternary benzo[c]phenanthridine alkaloids. The first step in sanguinarine metabolism is its reduction to dihydrosanguinarin. Antimicrobial and anti-inflammatory activities of these alkaloids are used in dentistry and as feed additives. Sanguinarine and chelerythrine induce apoptosis of cells. Fluorescence of these alkaloids and intercalation into DNA could be utilized to use the alkaloids as supravital DNA probe. Negative effect of sanguinarine and chelerythrine is their genotoxicity. Cytochrome P450 and peroxidase oxidize ellipticine to detoxication and activation metabolites. Ellipticine is a potent antineoplastic agent exhibiting the multimodal mechanism of its action. Ellipticine intercalates into DNA and inhibits topoisomerase II. Covalent DNA aducts are mediated by CYP or peroxidase oxidation of ellipticine. The anti-tumor activity of ellipticine and its derivatives is caused by a combination mechanism of cell cycle arrest and induction of the apoptotic pathway. Pharmacological efficiencies and geneotoxic side effects of ellipticine is dependent on levels and activities of cytochrome P450 or peroxidase in target tissues. Aristolactams are the major metabolites of biotransformation of aristolochic acid. Nitroreduction is the crucial step in formation of an...
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The electrochemical study of the degradation of the natural dyes from historical objects
Ramešová, Šárka ; Schwarzová, Karolina (advisor) ; Navrátil, Tomáš (referee)
The oxidation of quercetin (3,3',4',5,7-pentahydroxyflavone) and luteolin (3',4',5,7-tetrahydroxyflavone) has been studied. These intensively coloured polyphenolic compounds belong to a large group of naturally occuring flavonoid compounds. They were used with advantage as colourants in old tapestries. The study concerns the analysis of degradation processes of the original dyes. Degradation products formed during the ageing process can be used as fingerprints for the determination of the original colours. The degradation processes of flavonoid compounds were studied by electrochemical methods, absorption spectrometry and separation methods in aqueous media. The oxidation mechanism involves electron transfer coupled with chemical reaction and is influenced by the acidobasic properties of quercetin. The dissociation constants pK1 and pK2 of quercetin and pK1 and pK2 of luteolin were determined by combining of independent methods: acid-base titration and UV-Vis spectroscopy. The stability of both compounds significantly depends on the presence of the oxygen. The distribution of the oxidation products of quercetin in aqueous media within the exposure to oxygen was monitored by LC-MS/MS and LC- DAD analysis.
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Preparative diastereomeric separation of silybin and its sulfates by RP-HPLC
Kolářová, Petra ; Tesařová, Eva (advisor) ; Kalíková, Květa (referee)
Silymarin is standardized extract isolated from fruits of Milk Thistle plant (Silybum marianum). The principal component of silymarin is silybin. This flavonolignan is mainly responsible for the medicinal effects of Milk Thistle fruits: antioxidant, hepatoprotective, anticancer and chemoprotective activities. Natural silybin exists as an equimolar mixture of diastereomers A and B whose preparative separation is very hard. It was shown that the biological activity of silybin A and B are different. Silybin in the blood conjugates mainly to sulfates. The structure or biological activity of the sulfates is not yet known. The aim of this work is to develop practically applicable method for preparative separation of diastereomers of silybin A and B, and sulfates, which are considered as one of the major metabolites of silybin. The preparative method for separation of silybin A and B in the mobile phase consisting of 50% MeOH on the chromatographic column Labio C18 25x250 mm, was developed. In addition, preparative method for separation of mixture of products accured from the sulphation of silybin-23-acetate in the mobile phase consisting of MeOH/H2O 60/40 (v/v) with addition of 10 ml/l HCOOH, was optimized.
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Complexes of iron(II) salts and flavonoids
Schröpferová, Tereza ; Volný, Michael (referee) ; Roithová, Jana (advisor)
This work is devoted to a study of the interaction between iron(II) ions and flavonoids (epicatechin, catechin, quercetin) by means of mass spectrometry and electrospray ionization. First, a measurement with model molecules (pyrocatechol, resorcinol, 3-hydroxy-2-methyl-4- pyrone) has been performed in order to find how iron(II) intereacts with the OH groups on the hydrocarbon rings. It has been found that Fe2+ coordinates to epicatechin and probably also catechin (the measurement with catechin was unsuccesfull because of contamination by sodium) between the OH groups at the ring B and the fragmentation of the complex can proceed via a retro-Diels-Alder's reaction and thus lead to cleavage of the pyrone ring. Quercetin has at the pyrone ring the keto function next to the OH group, therefore the iron ion binds to these functions rather than to the OH groups at the ring B. Accordingly, the retro- Diels-Alder's reaction is not possible and the complex loses only small molecules of water and carbon oxide from the side rings as it was found for the complexes of model molecules.
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Stanovení flavonoidních látek ve vybraných druzích léčivých rostlin používaných v potravinářství
Bačová, Romana
In plant and food research the functional significance of herbs, spices and other plants, including their components is very popular topic. Plant material contains many components that are beneficial to human health by reducing the risk of chronic degenerative diseases. It is necessary to define the individual substances to understand and explain their biological effects. The first part of thesis describes the selected plants (elderberry, nettle, marigold, milk thistle, sea buckthorn, sage, purple coneflower and thyme) and also describes their medicinal properties and uses. The second part of thesis deals with phenolic and flavonoid substances. In the third (experimental) part, of thesis there were qualitatively and quantitatively determined flavonoid compounds in selected plant species. For identification the technique combining liquid chromatography and mass spectrometry - HPLC/MS was used. Extraction was carried out by vortexing and Soxhlet method, using two different concentrations of metanol. These metods were then statistically compared.
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Monitoring flavonoidních látek ve vybraných druzích medu
Sojková, Tereza
This work deals with flavonoid substances contained in honey. The work is to develop a theoretical part, which is focused on the composition of honey, its effects on human health and on the description of flavonoid substances. In the next section of the work is experimental part, which is shown in tables occurrence of phenolic compounds in different types of honey.
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Antioxidanty v bylinných čajích
Musilová, Eva
This bachelor's thesis "Antioxidants in Herbal Teas" brings a summary of substances with antioxidant properties contained in herbs used for production of herbal teas. The basic terms, e.g. oxidative stress, antioxidant, or free radical, are explained first. The individual groups of plant antioxidants (flavonoids, phenolic acids, terpenoids, chlorophylls etc.) are described in terms of their chemical structure and occurrence. There is also a brief introduction to methods for determining antioxidant activity (DPPH, TEAC, FRAP etc.). The next section focuses on the parts of plants used for production of herbal teas, tea preparation methods and characterization of selected herbs concerning their components with antioxidant effects. The final part of the thesis deals with the importance of antioxidants for human health in relation to particular diseases (cancer, cardiovascular and neurodegenerative diseases etc.).
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Změny v kvalitě měsíčkové drogy
Lekeš, Radek
On the base of charakterization using organs of mangold was attention focus on posibilities to influence substances in inflorescence, whose application is not relate just to terapeutic effects. Every group of substances has diferent curative properties, while in plant material affect complex of substances and some of them are more important than others. These are very sensitive to every patological change in plant or in harvested drug. Degradation of these substancies is posible to prevent by, more ways, which have to be in harmony with law. These motheds and proceses are aplicated on the base of knowledges about influence factors. Varieties, rezistence etc., are include in internal factors. Between external factors belong fertilization, or patogens.
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Vyhledávání a charakteristika genů zodpovědných za purpurové zbarvení obilek pšenice seté (Triticum aestivum L.)
Trojan, Václav
The purple color of the caryopses in common wheat (Triticum aestivum L.) is an example of the countless diversity of the Mother Nature. Red and white caryopses are typical in common wheat. Genotypes with purple caryopses are also described. This coloring is caused by anthocyanins which deposit in the pericarp (purple). The anthocyanins biosynthetic pathway is well described. The key enzyme is chalcone synthase (CHS). It catalyzes the first step. We observed the deposition of anthocyanins in the pericarp, the expression of a chalcone synthase gene and the amount of the major anthocyanin - cyanidin-3-glycoside (pericarp of purple caryopses) and delphinidin 3 gycoside during caryopsis development. Purple pigment deposition was not homogeneous and/or uniform. At first, small isolated spots of purple color were formed and thereafter they expanded. The expression of chalcone synthase mRNA occurred five days before pigment deposition and finished earlier than expected. Amounts of cyanidin-3-glycoside increased continuously. Amounts of these fell at the end of caryopses development probably due to formation of more complex substances, process which is described as copigmentation.
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