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Sulfates as phase II metabolites of natural phenolic compounds
Hetman, Anastasiia ; Mladěnka, Přemysl (advisor) ; Siatka, Tomáš (referee)
Charles University Faculty of Pharmacy in Hradec Králové Department of Pharmacology & Toxicology Student: Anastasiia Hetman Supervisor: Assoc. Prof. Přemysl Mladěnka, PharmD., Ph.D. Co-supervisor: Assoc. Prof. Kateřina Valentová, Ph.D. Title of diploma thesis: Sulfates as phase II metabolites of natural phenolic compounds Natural monophenolic compounds, which both occur in plants and are formed during gut microbiota metabolism of polyphenols, are absorbed and pass through phase II metabolism. This results in the formation of various conjugated metabolites, such as sulfates, whose biological activity was not studied as yet. This work focused on the preparation and isolation of pure sulfated metabolites of phenolic compounds, namely 4- methylcatechol, protocatechuic, homoprotocatechuic, and 2,3,4-trihydroxybenzoic acid, and phloroglucinol, using the aryl sulphotransferase from Desulfitobacterium hafniense. As a result, two sulfated products of sufficient purity were prepared, namely 4- methylcatechol-O-sulfate (an inseparable mixture of 4-methylcatechol-2-O-sulfate and 4- methylcatechol-1-O-sulfate) and phloroglucinol-O-sulfate. Their antioxidantactivity was evaluated and compared with the activity of the parent compounds using the following six in vitro tests: DPPH (1-diphenyl-2-picrylhydrazyl) and...
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Study of interaction of dihydromyricetin and alcohol in vivo
Vargová, Silvia ; Hodek, Petr (advisor) ; Kubíčková, Božena (referee)
- Abstrakt Dihydromyricetin (DHM), also known as ampelopsin, is a natural antioxidant found in the plant Ampelopsis grossedentata, traditionally used in Chinese medicine. Dihydromyricetin exhibits health-benefiting activities. Besides its antioxidative, anti-inflammatory, anticancer, and antimicrobial effects, it is said to suppress intoxication by alcohol and mitigate the symptoms of hangover and abstention. The mechanism of the activity of DHM on the metabolism of ethanol has not been fully explored. Thus, the focal point of the presented thesis was to explore the effect of DHM on the expression of CYP2E1, one of the major enzymes participating in the metabolism of ethanol in organisms. Male rats were administered with ethanol (EtOH) or ethanol in combination with DHM, and the EtOH concentration of the blood was determined. The amount of EtOH and acetaldehyde in the blood of individuals indicates that DHM does not affect the rate of EtOH metabolism. Subsequently, the effect of DHM on repeated premedication of EtOH was monitored. The group of rats treated with DHM showed a slower metabolism of EtOH than the group solely premedicated with EtOH. Ultimately, the effect of DHM on CYP2E1 expression was studied. Microsomal fractions were prepared from the rat livers. By use of Western blotting with a...
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Effect of dihydromyricetin on hepatic ethanol metabolism
Boubínová, Gabriela ; Hodek, Petr (advisor) ; Bebová, Michaela (referee)
Dihydromyricetin (DMH) is a natural flavonoid compound with positive effects on the human organism. In traditional Chinese medicine, plants containing DMH were used to treat liver diseases and to reduce alcohol intoxication. The effects of DHM on ethanol metabolism are not yet completely understood. Effects of DHM during alcohol intoxication were studied on primary hepatocytes of rats. DCFDA and DHR probes were used to prove that DHM (depending on concentration) reduces the number of reactive oxygen and nitrogen species in primary hepatocytes. However, the hepatoprotective effects of DHM were not achieved when presence of the alanine aminotransferase (ALT) was used to measure the damage of cells exposed to alcohol. Further, the effects of DHM on alcohol metabolism were studied in vivo. Rats were administered with single dose of ethanol or ethanol combined with DHM. Measured blood levels of ethanol and acetaldehyde show that DHM has no effects on the rate or levels of alcohol metabolism. The effects of DHM were also studied with repeated alcohol administration. In the group that was administered also DHM, increased blood levels of ethanol were measured. This points that DHM slow down the metabolic rate of ethanol. Obtained results did not prove any positive effects of DHM on alcohol metabolism....
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Interaction of myricetin with human gut microflora
Hucková, Pavlína ; Hodek, Petr (advisor) ; Killer, Jiří (referee)
The intestinal microbiome contributes in immune system function. It contains a large number of microorganisms that interact with each other and thus affect the host. Currently, attention is being directed towards investigating the influence of the intestinal microbiome on hosts, but also on foreign substances. Foreign substances may influence its composition and subsequent microbial metabolism. Crohn's disease patients have been found to have lower bacterial representation of beneficial bacteria. Therefore it is appropriate to examine the intestinal microbiome of these patients and so understand in greater detail the influence of bacteria on the course of the disease progression and on the medication used. The RP-HPLC method were analysed the faecal samples collected (B, C, D), which were incubated at 0, 3 and 6 hours. The incubation took place the addition of myricetin in the McDougall buffer and BHI medium. The analysis was found that myricetin degradation takes place in faecal samples during incubation, regardless of the medium used. In the faecal sample B, degradation of myricetin occurs faster in the BHI medium than in the McDougall's buffer. In faecal samples C and D, degradation is similar in both media. From these results, it is impossible to judge which medium is more suitable for...
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Antiplatelet effects of flavonoids
Kopková, Nikola ; Mladěnka, Přemysl (advisor) ; Jirkovský, Eduard (referee)
Charles University Faculty of Pharmacy in Hradec Králové Department of Pharmacology & Toxicology Student: Nikola Kopková Supervisor: Assoc. Prof. Přemysl Mladěnka, Pharm.D., Ph.D. Title of diploma thesis: Antiplatelet effects of flavonoids The most common antioxidants in ordinary food are flavonoids. They show antioxidant and anti-aggregation effects and other positive effects on cardiovascular diseases. Flavonoids are promising candidates to be antiplatelet drugs. Although several mechanisms responsible for antiplatelet activity have been suggesteed, only a few have been documented by published studies. The inhibition of blood platelet aggregation by flavonoids is reversible, which is another important factor. Data on thrombin-induced aggregation are controversial, some claim that flavonoids have no effect, the others says they have positive effects. (In the case of quercetin and genistein, inhibition of aggregation induced by thrombin was documented). The effect on arachidonic acid in the aggregation cascade is well documented, but there are several inconsistencies resulting from the use of different materials. Other mediators of aggregation are phospholipase A2, which plays a key role in the formation of inflammatory mediators. In this case, it has been shown that mainly genistein is capable of...
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Enzymatic modifications of bioactive flavonoids
Rydlová, Lenka ; Tesařová, Eva (advisor) ; Wimmer, Zdeněk (referee)
Extract from milk thistle (Silybum marianum (L.) Gaertn., synonym Carduus marianus L., Asteraceae) silymarin contains among others primarily bioactive flavonolignans. They have hepatoprotective and antioxidative effects and also anticancer, chemoprotective, dermatoprotective and hypocholesterolemic activity. This thesis focuses on the preparation of metabolites of the second phase of biotransformation unexplored flavonolignans 2,3-dehydrosilybin (DHSB), silychristin (SCH), 2,3-dehydrosilychristin (DHSCH). Pure sulfated derivatives were prepared using aryl sulfotransferase from Desulfitobacterium hafniense and p-nitrophenyl sulfate (p- NPS) as a donor. Flavonolignans yield exclusively monosulfates at the position C- 20 (C-19 in the case of silychristin and 2,3-dehydrosilychristin), except for 2,3- dehydrosilybin that gives also the 7,20-disulfated derivatives. For all samples were made antioxidant tests - DPPH assay (the highest activity had 2,3-dehydrosilychristin sulfate: IC50= 7,87 µM), Folin-Ciocalteau reduction assay (the highest activity had 2,3-dehydrosilychristin: 1,58 ekvivalents of gallic acid), ABTS+ scavenging (the highest activity had silychristin: 1,50 ekvivalents of vitamin C), inhibition of microsomal lipid peroxidation (the highest activity had 2,3-dehydrosilybin: IC50 = 10,6 µM),...
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Alkaloid and flavonoid content in Fontinalis antipyretica Hedw.
Ptáčníková, Lucie ; Martin, Jan (advisor) ; Tůmová, Lenka (referee)
Lucie Ptáčníková, The volume of alkaloids and flavonoids in Fontinalis antipyretica, Thesis, Charles University in Prague, Faculty of Pharmacy in Hradec Králové, thesis tutor: PharmDr. Jan Martin, PhD., Hradec Králové, 2012, 55 pages. Thesis called "Content of alkaloids and flavonoids in Fontinalis anitpyretica" establishes alkaloids and flavonoids and identifies one substance of these alkaloids in the above-mentioned water moss. The main purpose of this thesis was to obtain samples of Fontinalis antipyretica from selected locations in the Czech Republic (Ledce, Rychnovek, Kunvald). Next purpose was to determine alkaloids and flavonoids of collected material, isolated one substance of alkaloid character and verify identity of selected alkaloid. The content of alkaloids and flavonoids was determined by using the high-performance liquid chromatography (HPLC). The results show that β - carboline alkaloid harmin was determined by consensus UV spectrum and retention time with standard. Consequently flavonoids called myricetin and hyperosid was determined. Identity of β - carboline alkaloid harmin was verified by using NMR analysis. Keywords: alkaloids - harmalol - harmin - Fontinalis antipyretica - flavonoids
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Structure-function analysis of selected hop (Humulus lupulus L.) regulatory factors
FÜSSY, Zoltán
This work concentrated on isolation of novel hop transcription factors from bHLH, bZIP, MYB, and WRKY families involved in the regulation of lupulin flavonoid pathways, followed by their structural and functional analysis. Structural analyses included bioinformatic approaches to elucidate gene organization, domain structure of the putative protein products, and potential post-translational modifications. I performed site-directed mutagenesis to disclose the role of phosphorylation sites in HlbZIP1A stability. Further, this work determined protein-DNA interactions for obtained TFs, giving support to the binding of MYB-bHLH-WDR complexes to the promoter of chalcone synthase H1, a key enzyme of the lupulin flavonoid pathways. Employing bioinformatic approaches, quantitative RT-PCR and transient co-expression, I pointed out chalcone synthase H1 as a regulatory crossroads in the metabolic (flavonoid) responses during hop stunt viroid pathogenesis.
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