National Repository of Grey Literature 109 records found  beginprevious55 - 64nextend  jump to record: Search took 0.01 seconds. 
Technologie pěstování Leuzey saflorové (Leuzea carthamoides DC.) a její využití.
VYTISKA, Petr
This bachelor thesis deals with the technology of growing leuzea carthamoides DC., the substances it contains and its possible pharmaceutical use. Next I deal with the description of some substances found in the above ground or underground parts of the plant. Among the most effective substances that leuzea contains are phytoecdysteroids, triterpens, flavonoids, thiophenes and phenolic acids. The quantity of these substances depends directly on the way of cultivation, selection of the appropriate habitat, the use of elicitors and the drying and harvesting technology. In the final part I deal with the research how the public is familiar with leuzea as a medical plant.
Differences in Oxidation Mechanism of Selected Bioflavonoids, UV-Vis and IR Spectroelectrochemical Study
Sokolová, Romana ; Fiedler, Jan ; Ramešová, Šárka ; Kocábová, Jana ; Degano, I. ; Quinto, A. ; Křen, Vladimír
The oxidation of selected bioflavonoids (quercetin, rhamnazin, fisetin, rhamnetin, taxifolin, luteolin, silybin and 2,3-dehydrosilybin) was studied by electrochemical and spectroscopic methods. The oxidation mechanism and formation of oxidation products depends on the chemical structure. Only small differences in the chemical structure of compounds with flavone, flavanone and flavonol motif result in extremely variable oxidation pathways and products. Products of oxidation and further decomposition were determined by HPLC-ESIMS/MS and HPLC-DAD.
Effects of some flavonoids in isolated rat aortic rings
Pešková, Hana ; Vopršalová, Marie (advisor) ; Pourová, Jana (referee)
Charles University Faculty of Pharmacy in Hradec Králové Department of Pharmacology & Toxicology Student: Hana Pešková Supervisor: PharmDr. Marie Vopršalová, CSc. Title of diploma thesis: Effects of some flavonoids in isolated rat aortic rings Flavonoids with their wide range of effects are known for having positive influence on human health. It mainly concerns significant antioxidant and anti- inflammatory characteristics and cardiovascular diseases incidence reducing effects. The aim of this study was examination of vasorelaxant effects of selected flavonoids from isoflavonoid group: formononetin, isoformononetin, prunetin and ononin, occuring especially in Fabaceae family. The vasorelaxation potential of tested substances was examinated in in vitro conditions on isolated aortic rings of rat. The effect of increasing doses of individual flavonoids on preparation, with intact endothelium after previous precontraction with norepinefrine, was monitored (10-5 M). From measured values, there were DRC curves, EC50 values created and an evaluation was made. According to analysis of the results, the most significat activity has fromononetin (EC50 2,081 . 10-5 M) and isoformononetin (EC50 2,081, 10-5 M). Ononin showed almost no vasodilatory effect.
The antioxidant activity of St. John's wort explantate cultures
Vrabec, Rudolf ; Martin, Jan (advisor) ; Spilková, Jiřina (referee)
St. John's wort is a herbal medicine well known for its anti-depressant effect. It contains anthraquinone derivates, prenylated floroglucinols, tannins, hydroxycinnamic acids, and especially flavonoids, which have a wide range of biological effects on the body including antioxidant properties. Antioxidants are one of the possibilities to protect body from harmful influences of free radicals - highly reactive particles that damage biological structures. In this work, two methods (DPPH and superoxide radical) were used to determinate antioxidant activity of methanolic and aqueous extracts of dried St. John's wort - Hypericum Perforatum L. and its callus and suspension explant cultures. The results are processed into tables and graphs which compare the effectiveness of extracts to quench the radicals. EC50 for the methanolic extract was 0,064 mg/ml and for the aqueous extract 0,068 mg/ml. EC50 for the aqueous extract was 16,727 mg/ml, but unfortunatelly the other antioxidant activity values for EC50 were too low to evaluate. Determination of the content of flavonoids hyperoside and quercetin by high performance liquid chromatography shows that their highest content is in the drug extracts and that the explant cultures have negligible content of the flavonoids. There is no content of hypericin in all...
Secondary metabolites of plant cultures in vitro I
Zlochová, Pavlína ; Kašparová, Marie (advisor) ; Siatka, Tomáš (referee)
Charles University, Faculty of Pharmacy in Hradec Králové Department of Pharmacognosy Candidate: Pavlína Zlochová Supervisor: PharmDr. Marie Kašparová, Ph.D. Title of diploma thesis: Secondary metabolites of plant cultures in vitro I. Key words: Suspension cultures, Trifolium pratense, phytoestrogens, flavonoids, isoflavonoids Explant cultures are source of plant secondary metabolites. Nevertheless the production of secondary metabolites is usually low in explant cultures. This production can be increased by elicitation metods. Suitable elicitor is added into the cultivate medium and leads to gene expression and production of secondary metabolites. The aim of this study was to observe the influence of sodium chloride on the production of flavonoids and isoflavonoids by the Trifolium pratense L. suspension culture (Tempus variety). The culture was cultivated on Gamborg nutriet medium with addition of 2 mg.l-1 2,4- dichlorophenoxyacetic acid and 2 mg.l-1 6-benzylaminopurine. Cultivation proceed in 25řC temperature and 16 hours light/8 hours dark period. Then determination of flavonoids in according to Czech Pharmacopoeia 2009 and the determination of isoflavonoids by HPLC method was performed. The best elicitation effect on the production of flavonoids was 175 mmol.l-1 of sodium chloride after a 3...
Enzymatic and Metabolic Transformation of Silybin and its Congeners
Purchartová, Kateřina ; Křen, Vladimír (advisor) ; Macek, Tomáš (referee) ; Vítek, Libor (referee)
Natural flavonoids and flavonolignans feature beneficial properties for living organisms such as antioxidant and hepatoprotective effects, anticancer, chemoprotective, dermatoprotective and hypocholesterolemic activities. Their metabolism in mammals is complex, the exact structure of their metabolites still remains partly unclear and the standards are usually not commercially available. Hence, this project focused on the preparation of potential and defined biotransformation Phase II sulfated metabolites of silymarin flavonolignans: silybin, 2,3-dehydrosilybin, isosilybin, silychristin, silydianin and flavonoids quercetin, taxifolin, rutin and isoquercitrin. Pure sulfated derivatives were prepared using aryl sulfotransferase from Desulfitobacterium hafniense and aryl sulfotransferase from rat liver. Using heterologously expressed PAPS (3'-phosphoadenosine-5'-phosophosulfate) - independent arylsulfotransferase from Desulfitobacterium hafniense and cheap p-nitrophenyl sulfate as sulfate donor, sulfated flavonolignans and flavonoids were obtained in high yields. Silymarin flavonolignans afforded exclusively monosulfates at the position C-20 (C-19 in the case of silychristin), except 2,3-dehydrosilybin that yielded also the 7,20-O-disulfated derivative. Isoquercitrin and rutin were selectively sulfated...
Flavonoids in some cultivars of Sambucus nigra L. flowers.
Krulišová, Markéta ; Spilková, Jiřina (advisor) ; Martin, Jan (referee)
The aim of this work was to find out the content of flavonoids in the flowers of eleven cultivars of black elder (Sambucus nigra L.) and determine if their contents differ according to the statistical significance. Preparing the list of effects and substances that are contained in the flowers was the goal as well. The drug Sambuci nigrae flos is mostly used for its content of flavonoids and hydroxycinnamic acids in the therapy of colds and diseases of the urinary and respiratory tract. Its benefits were confirmed also by studies testing antibacterial and antiviral activity, diabetes and obesity, effects on the immune system and also protection against UV radiance. The content of flavonoids was established by the spectrophotometric method that is listed in the Czech Pharmacopoeia 2009 in the article Sambuci nigrae flos as the method for the determination of content. The statistic evaluation of the differences in the flavonoids content between the cultivars was made by ANOVA and the Bonferroni test. The demand of Czech Pharmacopoeia 2009 on the minimal content of flavonoids is 0,80%. This requirement was fulfilled in the flowers of these cultivars: Albida, Heidegg 13, Riese auß Voßloch, Sambu, Samdal, Sampo and Samyl. On the opposite side, flowers of the cultivars Allesö, Aurea, Dana and Juicy did...
Effects of selected natural substances on the antioxidant system of an organism
Hodková, Anna ; Eybl, Vladislav (advisor) ; Mayer, Otto (referee) ; Anzenbacherová, Eva (referee)
of study named: Effects of selected natural substances on the antioxidant system of an organism Developed: Mgr. Anna Hodková Department of Pharmacology and Toxikology, Faculty of Medicine in Pilsen, Charles University in Prague Pilsen 2016 The aim of this study was to compare the effects of selected natural substances on the antioxidant defense system under comparable conditions, focusing on influencing the activity of selenoenzymes thioredoxin reductase (TrxR-1) and glutathione peroxidase (GPx-1). Experiments were performed in rats (Wistar, male). Livers, and in some cases kidneys were collected in all experiments. Homogenates were created from the collected organs and subsequently the activity of TrxR-1 and GPx-1, glutathione reductase (GR), catalase (CAT) and superoxide dismutase (SOD), and reduced glutathione (GSH) and lipid peroxidation (LP) levels were determined. We demonstrated significant effects of selected natural substances on the redox system, including influences of selenoenzymes thioredoxin reductase and glutathione peroxidase. The biggest influence on the activity of selenoenzymes thioredoxin reductase and glutathione peroxidase had hydroxytyrosol (HT) and oleuropein (OLEU). In rat liver tissue there was a significant decrease of the activity of both above mentioned enzymes after...
Study of effect of flavonoids on biotransformation enzymes expression
Koucká, Kamila ; Moserová, Michaela (advisor) ; Mrízová, Iveta (referee)
Flavonoids belong to the group of phenolic compounds included in the secondary metabolites of plants, which are represented mainly in fruits and vegetables. These compounds have antioxidant and anti-carcinogenic effects. Some of them can affect biotransformation enzymes, which include the cytochrome P450 and can interfere with the metabolism of xenobiotics. In the present work we studied effect of dihydromyricetine on the gene expression of cytochrome P450 1A1, 1A2 and cytochrome b5 in livers, lungs, kidneys, colon and small intestine of laboratory rats. The small intestine was divided into three parts namely a proximal, middle and distal. At first, isolation of total RNA was made using commercial reagents and isolated RNA was converted to cDNA by reverse transcription. Finally, using polymerase chain reaction in real time (RT-PCR), the relatively gene expression of genes observed in the organs of laboratory rats pretreated dihydromyricetine and control laboratory rats (untreated) to a reference gene β-actin was determined. It was found that dihydromyricetine did not significantly affect the gene expression of studied genes in most organs. However, a significant decrease of gene expression of CYP1A1 and CYP1A2 was observed in the lungs. On the contrary, an increase of gene expression of CYP1A2 was...
Enzymatic and Metabolic Transformation of Silybin and its Congeners
Purchartová, Kateřina
Natural flavonoids and flavonolignans feature beneficial properties for living organisms such as antioxidant and hepatoprotective effects, anticancer, chemoprotective, dermatoprotective and hypocholesterolemic activities. Their metabolism in mammals is complex, the exact structure of their metabolites still remains partly unclear and the standards are usually not commercially available. Hence, this project focused on the preparation of potential and defined biotransformation Phase II sulfated metabolites of silymarin flavonolignans: silybin, 2,3-dehydrosilybin, isosilybin, silychristin, silydianin and flavonoids quercetin, taxifolin, rutin and isoquercitrin. Pure sulfated derivatives were prepared using aryl sulfotransferase from Desulfitobacterium hafniense and aryl sulfotransferase from rat liver. Using heterologously expressed PAPS (3'-phosphoadenosine-5'-phosophosulfate) - independent arylsulfotransferase from Desulfitobacterium hafniense and cheap p-nitrophenyl sulfate as sulfate donor, sulfated flavonolignans and flavonoids were obtained in high yields. Silymarin flavonolignans afforded exclusively monosulfates at the position C-20 (C-19 in the case of silychristin), except 2,3-dehydrosilybin that yielded also the 7,20-O-disulfated derivative. Isoquercitrin and rutin were selectively sulfated...

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