National Repository of Grey Literature 199 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Plant alkaloid sanguinarine and its derivatives
Tůmová, Lucie ; Stiborová, Marie (advisor) ; Hýsková, Veronika (referee)
This work is summarizing actual knowledge about sanguinarine and quaternary benzo[c]fenanthridine alkaloids. The quaternary benzo[c]fenanthridine alkaloids were found in roots plants Sanguinaria canadensis and Macleaya cordata. This plants are used in tradicional Chinese medicine for its antimycotic, antibacterial and anti-inflammatory activities since antiquity. Regarding to possibility quaternary benzo[c]fenanthridine alkaloids to induce apoptosis these investigated such as possible agents for cancer treatment. The quaternary benzo[c]fenanthridine alkaloids interact with DNA and proteins. They are able to intercalate to the DNA. The alkaloids can be used like fluorescence DNA probe. Metabolism by sanguinarine and next quaternary benzo[c]fenanthridine alkaloids has not yet completely determinated. The first step sanguinarine detoxication is its conversion to less toxic dihydrosanguinarine. Sanguinarine oxidation is mediated by cytochrome P450 1A1. Key words: Quaternary benzo[c]fenanthridine alkaloids, sanguinarine, apoptosis, intercalate, heterogenous substances, enzymes, cytochrom P450
Activity of cytochromes P450 1A1, 1A2 and 3A4 expressed in eukaryotic and prokaryotic systems
Indra, Radek ; Stiborová, Marie (advisor) ; Mizerovská, Jana (referee)
Cytochromes P450 (CYP) are a superfamily of heme proteins distributed widely throughout nature, involved in metabolism of a broad variety of substrates and catalyzing a variety of interesting chemical reactions. They play a central role in metabolism of chemotherapeutic agents. Several prodrug antitumor agents have been found as CYP substrates. Ellipticine, an alkaloid found in Apocynaceae plants, is an example of such type of pro-drug. Here, we investigate the efficiencies of human recombinant CYPs expressed in eukaryotic and prokaryotic expression systems, namely in SupersomesTM , microsomes isolated from insect cells transfected with baculovirus construct containing cDNA of human CYP1A1, 1A2 and 3A4 with NADPH:CYP reductase or in Bactosomes, the membrane fraction of E. coli transfected with cDNA of the same human CYP enzymes and NADPH:CYP reductase to oxidize their marker substrates and ellipticine. Cytochrome b5, an aditional component of the mixed function oxidase system, which metabolize xenobiotics was also expressed in some of the systems. The results found in this work demonstrate that human CYP1A1, 1A2 or 3A4 expressed in both eukaryotic and procaryotic systems oxidize their marker substrates (EROD for CYP1A1/2, MROD for CYP1A2 and testosterone 6β-hydroxylation for CYP3A4). They also oxidize...
The study of properties of anticancer drugs ellipticine, etoposide and doxorubicin in the forms of nanocarriers
Lengálová, Alžběta ; Stiborová, Marie (advisor) ; Martínková, Markéta (referee)
Currently available anticancer therapies are inadequate and spur demand for improved technologies. Among others, the utilization of nanocarriers for anticancer drug delivery has shown great potential in cancer treatment. Nanocarriers can improve the therapeutic efficiency of the drugs with minimization of the undesirable side effects. To evaluate potential application of this technology, two forms of nanocarriers have been studied: multi-walled carbon nanotubes (MWCNTs) and apoferritin. The aim of this study was to determine, whether given cytostatics (ellipticine, etoposide and doxorubicin) are bound to these nanotransporters and how are they released from them, especially depending on pH. Since the pH of the tumor cells is lower than the pH of healthy cells it would be preferred that the drugs would release from nanocarriers at the lower pH while at the physiological pH the release of the drug would be eliminated. The results found show that ellipticine is actually released from its MWCNT- and apoferrtin-encapsulated form at acidic pH (5.0), while at pH 7.4 its interaction with nanocarriers is stable. Ellipticine released from MWCNT is activated by microsomal enzymes to reactive metabolites (13- hydroxyellipticine and 12-hydroxyellipticine) forming DNA adducts. The results indicate that both...
Chemoenzymatic separation of diastereoisomers of silybin
Purchartová, Kateřina ; Stiborová, Marie (advisor) ; Wimmer, Zdeněk (referee)
Silybin is major component of silymarin isolated from seeds of the milk thistle (Silybum marianum). This compound is widely used in human medicine against liver disorders and as a protectant against a number of hepatotoxins. It also exhibits other interesting activities as anticancer and chemoprotective, dermatoprotective and also hypocholesterolemic effects. Natural silybin is a nearly equimolar mixture of two diastereoisomers, silybin A and silybin B, whose analytical separation is quite feasible, but preparative separation is extremely complicated. The aim of this work was to find suitable method leading to separation of both silybin diastereoisomers. A library of hydrolases (lipases, esterases and proteases) was tested for their diastereoisomeric discrimination of the selective alcoholysis of 23-O-acetylsilybins. Novozym 435 (lipase B from Candida antarctica immobilized on acrylic resin) proved to be the most suitable enzyme for the preparative production of both optically pure silybin A and B by enzymatic hydrolysis. Under the optimized conditions, silybin A was obtained in 42 % yield and 97 % purity while silybin B was obtained in 67 % yield and 99 % purity. Covalent modifications of Novozym 435 (acetylation, succinylation, and hydroxyethylamidation), which should lead to improvement of...
Study of mechanism of action of anticancer drug ellipticine and its metabolism
Vejvodová, Lucie ; Stiborová, Marie (advisor) ; Moserová, Michaela (referee)
This bachelor thesis is aimed to study the mechanisms of action of anticancer drugs, their side effects, their resistance and pharmacokinetics. Anticancer alkaloid ellipticine was chosen as a model for this work. Bachelor thesis describes the metabolism of this substance in organisms and its potential to induce of drug metabolizing enzymes. An antineoplastic alkaloid ellipticine is a prodrug, whose mode of action is based mainly on DNA intercalation, inhibition of topoisomerasa II, and formation of covalent DNA adducts mediated by cytochromes P450 and/or peroxidases in target tissues. A variety cytochromes P450 oxidize ellipticine forming up to five metabolites (7-hydroxyellipticine, 9- hydroxyellipticine, 12-hydroxyellipticine, 13-hydroxyellipticine and ellipticine N2 - oxide). 7- hydroxy- and 9-hydroxyellipticine metabolites are considered to be mainly the detoxication products of ellipticine, while 12-hydroxyellipticine, 13-hydroxyellipticine and ellipticine N2 - oxide are considered to be mainly the activation products of ellipticine. The major ellipticine- derived DNA adducts are generated from these activation metabolites. These adducts were found in cancer cells in culture, such as human breast adenocarcinoma MCF-7 cells, neuroblastoma IMR-32, UKF-NB-3, and UKF-NB-4 cells and glioblastoma...
Study of Styrene-7,8-oxide Adducts with Cysteine, Histidine and Lysine in Human Clobin
Jágr, Michal ; Pacáková, Věra (advisor) ; Stiborová, Marie (referee) ; Kuchař, Miroslav (referee) ; Novák, Jan (referee)
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Mechanism of tumor development and its influencing by ellipticine
Parisová, Martina ; Stiborová, Marie (advisor) ; Moserová, Michaela (referee)
Ellipticine (5.11-dimethyl-6H-pyridate [4,3-b] carbazole) is a powerful anti-cancer agent, exhibiting multiple mechanisms of action. This work describes the causes of cancer processes and summarizes the main pharmacological mechanisms and cytotoxic effects of ellipticine together with the results found in our laboratory indicating, a new mechanism of ellipticine action. Cytotoxic and mutagenic activity of ellipticine is attributed to its two mechanisms of activity ellipticine intercalation into DNA and its effectivity to inhibit topoisomerase II. Ellipticine also forms covalent DNA adducts after its oxidation with cytochromes P450 and peroxidases. Cytochromes P450 oxidize ellipticine up to five metabolites, of which 13- hydroxyellipticin, 12-hydroxyellipticin and N(2)-oxide of ellipticine are responsible for formation of two major DNA adducts. In the case of peroxidases, ellipticine is oxidized to a radical producing the ellipticine dimer and a minor ellipticine metabolite, the N(2)-oxide of ellipticine. Because of the high efficiency of ellipticine and its derivatives against various types of cancer, this coumpound is studied in detail. Its utilization for drug tangeting is a challenge for further study.

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See also: similar author names
1 Stiborová, Marie Luisa
1 Stiborová, Markéta
2 Stiborová, Martina
2 Stiborová, Milada
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