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Isolation of antimicrobial compounds from spent coffee grounds
Kurzová, Pavlína ; Veselá, Mária (referee) ; Kovalčík, Adriána (advisor)
Coffee grounds are one of the very valuable lignocellulosic wastes that have been able to be processed and used for isolated phenolic substances. Many phenolic substances isolated from lignocellulosic wastes have antimicrobial properties. Aim of this thesis is isolation phenolic substances from spent coffee grounds extract and their available antimicrobial properties. Two isolation ways were applied to receive phenolic substances from spent coffee grounds: 1) solvent extraction (hexane, 75% ethanol, 70% acetone, diethyl ether, and ethyl acetate) and 2) release of active substances by alcoholic fermentation. All isolated materials were characterized by the viewpoint of concentration of reducing sugars, polyphenols and flavonoids. Subsequently, their antimicrobial activity was determined by using agar diffusion and broth dilution methods. Two gram-positive bacteria (Bacillus subtilis and Micrococcus luteus), one gram-negative bacteria (Serratia marcescens) and two yeasts (Candida glabrata and Saccharomyces cerevisiae) were used for antimicrobial testing. High-performance liquid chromatography (HPLC) was used to identify phenolic substances in the extracts. First, the results showed that the isolated sample with the highest antimicrobial activity was 70% acetone extract. This extract contained chlorogenic acid, gallic acid, caffeic acid and coumaric acid according to HPLC. The ethyl acetate extract showed the lowest antimicrobial activity. Second, after lyophilization, the isolated materials also revealed high antimicrobial activity. The highest antimicrobial activity displayed the materials obtained by the extraction with 70% ethanol. This sample contained chlorogenic acid, gallic acid and caffeic acids. Next, samples with phenolic compounds were obtained by the alcoholic fermentation of spent coffee grounds. These samples showed similarly to the previous solution extracts significant antimicrobial activity. Interestingly, the unfiltered samples received directly after alcoholic fermentation also showed antifungal properties. The characterization of phenolic compounds by HPLC showed similarly as in previous examples that chlorogenic, caffeic and gallic acids were present in these samples.
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Isolation and characterizaation of oil from some types of coffee
Vašků, Barbora ; Hoová, Julie (referee) ; Skoumalová, Petra (advisor)
Coffee, extract, oil, phenolic compounds, flavonoids, antioxidant capacity, SPF, critical wavelenght.
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Study of natural compounds of elderberry flowers
Pončíková, Alžbeta ; Skoumalová, Petra (referee) ; Veselá, Mária (advisor)
The aim of this bachelor thesis was to determine the concentration of bioactive substances such as polyphenols and flavonoids and also the total antioxidant capacity in extracts from flowers of elder. The second part was the subject of an experiment to determine the antimicrobial activity. The theoretical part deals with the description of individual bioactive substances, the description of the elder and the bacteria used. In the experimental part, aqueous extracts were prepared, in which total polyphenols, flavonoids and oxidizing activity were determined. The results of the determination of polyphenols and flavonoids show that in order to achieve a higher content of flavonoids and polyphenols, it is more appropriate to use the highest possible initial temperature for leaching the base flower. No significant differences were found when comparing the antioxidant activity of solutions from the average values. The extracts did not show significant antimicrobial activity.
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Determination of athenticity of plant foods by molecular techniques
Plášková, Anna ; Mikulíková, Renata (referee) ; Němcová, Andrea (advisor)
The aim of presented diploma thesis was to determination of authenticity of fruit baby foods for early infant feeding using molecular methods. In the experimental part, isolation kit was used for isolation of plant DNA from fruits (strawberry, apricot, raspberry, apple) and from six commercial fruit products for children. Isolated DNA was characterized and verified using PCR methods with primers specific for plant rDNA (ITS2). Specific primer pairs were designed to amplify DNA for the detection of one fruit species. Primer specificity was assessed with four fruit species. A mixture of fruit puree from the two fruits was used to determine the sensitivity of the multiplex PCR assay. Six commercial fruit products were evaluated to verify the applicability of the multiplex PCR assay. The methodology of molecular detection of fruit DNA by qPCR and multiplex qPCR (duplex) includes approaches, which enable to detect two fruits (strawberry-raspberry, apricot-apple) in one reaction and thus reduces time and money requirements.
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The effect of pyrazine derivatives on secondary metabolites content in plant cultures in vitro I.
Graclíková, Bohumila ; Tůmová, Lenka (advisor) ; Siatka, Tomáš (referee)
1 Abstract Elicitation method is one way to increase the production of secondary metabolites in in vitro of plant cultures and this work deals with this problem. Its aim was to find the positive effect of 2-hydroxy-4-(imidazo[1,2-a]pyrazine-2-carboxamide)benzoic acid from the group of pyrazine derivates on the production of isoflavonoids in in vitro cultures of Genista tinctoria L. Isoflavonoids play an important role in therapy of climacteric problems or they are promising substances of therapy various cancer types due to their affinity to estrogens β-receptors. This plant or rather its in vitro cultures are a potencial sources of isoflavonoids. Suspension and callus cultures of Genista tinctoria L. were used for elicitation. They were cultivated on Schenk & Hildebrant medium with the addition of 2,4-dichlorophenoxyacetic acid (2,4-D) as growth regulator at a concentration of 1 ml/l. The elicitor solution was added to the cultures at three concentrations: 3.3642 × 10-3 mol/l; 3.3642 × 10-4 mol/l; 3.3642 × 10-5 mol/l. The samples were taken at intervals of 6, 24, 48, 72 and 168 hours and then they were analyzed by HPLC method. At the same time intervals the samples of medium, where isoflavonoids were released, were analyzed. The biggest production of isoflavonoid was reached in suspension culture. The...
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Effect of dihydromyricetin on ethanol metabolism
Skotnicová, Aneta ; Hodek, Petr (advisor) ; Koblas, Tomáš (referee)
Dihydromyricetin (DHM), also ampelopsin, is a flavonoid compound which exhibits a broad spectrum of positive effects on the human body. Herbal extracts containing this compound have been widely used in traditional Chinese medicine mainly for their hepatoprotective properties. DHM also helps with alcohol intoxication and reduces the signs of hangover or abstinence. Given the fact that the mechanism of DHM effects on the ethanol metabolism has not been clarified yet, the effect of dihydromyricetin on the expression and activity of alcohol dehydrogenase (ADH), one of the most important enzymes involved in ethanol metabolism, was therefore studied in this thesis. The cultivation conditions of primary hepatocytes which were isolated from unpretreated and ethanol-pretreated rats and subsequently exposed to EtOH and DHM were optimized. While determining the degree of cell damage caused by EtOH in the presence of DHM, no significant trend in the protective effect of DHM was found. On the other hand, the protective effect of ethanol in hepatocytes cultivated in EtOH and DHM was detected by technique of ELISA (the determination of alanine transaminase). The Western blot technique followed by immunodetection did not detect the induction of ADH expression in hepatocytes. Furthemore, the modulation effect of...
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Characterization of intermediates and waste products of some fermentation productions
Kilian, David ; Skoumalová, Petra (referee) ; Márová, Ivana (advisor)
This bachcelor thesis was aimed on characterisation of intermediate and waste products of some fermentation productions. The theoretical part of this thesis is aiming on characterization of raw material and its fermentation, process of distillation, waste product and introduction of main active components of all these intermediates. In the experimental part were characterized intermediates and products regarding the contents of sugar, ethanol and polyphenol. All these extracts contain particular levels of polyphenol and sugar corresponding to individual phases of fruit distillates production. The chemical characteristics of extracts from different phases of fruit distillates production were compared. Parameters as total phenolics, flavonoids, glucose, fructose and ethanol were evaluated. Subsequently the changes between individual phases were described. In conclusion, a solution of further use of waste products formed during fruit fermentation process was suggested.
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Study of antimicrobial substances of ginger
Ciburová, Alena ; Skoumalová, Petra (referee) ; Veselá, Mária (advisor)
For thousands of years ginger rhizomes are used in traditional Chinese medicine. Because of his significant pungent flavour is commonly used in foods and beverages all over the world. Nowadays many of the beneficial pharmacological positive effects of ginger rhizomes are identified. Their occurrence is due to the high concentration of bioactive compounds. This thesis is focused on analysing of occurrence of bioactive compounds such as polyphenols and flavonoids and their influence on antioxidation and antimicrobial properties of samples of fresh and dried ginger. The results show that for extraction of bioactive compounds in different ginger samples is more suitable to use different types of extraction solvents. The highest antioxidation activity was measured for macerate of 100% bio ginger tea from Sonnentor company in 96% ethanol. Antimicrobial properties were showed only for 100% bio ginger tea against gram-positive bacteria Microccocus luteus.
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The effects of some flavonoids on isolated rat aortic rings
Fišrová, Martina ; Vopršalová, Marie (advisor) ; Pourová, Jana (referee)
Charles University Faculty of Pharmacy in Hradec Kralove Department of Farmacology & Toxikology Student: Martina Fišrová Supervisor: PharmDr. Marie Vopršalová, CSc. Title of diploma thesis: The effects of some flavonoids on isolated rat aortic rings Flavonoids are secondary plant metabolites that are profusely represented in nature. They are known for their wide range of effects and many of them have beneficial effects on the human body. Above all, they have anti-bacterial and anti-inflammatory properties and effects on cardiovascular system - they cause vasodilation. The aim of this diploma thesis was to investigate vasorelaxation effects of selected flavonoids from the group of flavonolignans - 2,3-dehydrosilybin A (DHS-A), 2,3-dehydrosilybin B (DHS-B) and metabolites, which are components of the silymarin complex found in the plant Silybum marianum (Asteraceae). The vasorelaxation potential of tested substances was verified in ex vivo conditions on isolated rat aortic rings. The effect of increasing doses of individual substances in precontracted aortic rings with intact endothelium was measured. From the measured values, the DRC curves were constructed and EC50 values were determined. The analysis of the results shows, that DHS-A (EC50 = 30,1 mol/l) had the most signifiant activity. Its...
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Phenolic substances in algae
Ráček, Jan ; Pichrtová, Martina (advisor) ; Pilátová, Jana (referee)
Phenolic substances are considered to be a group of secondary metabolites, known primarily from land plants (Embryophyta). Their function is to absorb harmful ultraviolet radiation, to protect plants from grazing and to attract pollinators and seed spreaders. However, these compounds have also been reported in some phylogenetically unrelated algal groups, the most important of which are brown algae (Phaeophyceae), siphonous green algae from the Dasycladaceae family and conjugating algae (Zygnematophyceae). The aim of this work is to summarize the current knowledge about phenolic compounds of these groups with an emphasis on their significance for the biology of the species. The first part describes phenolic compounds in general and also outlines the way they are biosynthesized. The next chapters then deal with the three algae groups. The most explored ones in this area are brown algae, which contain a unique type of tannins called phlorotannins in their thallus. This is followed by green siphonous algae from the family Dasycladaceae, which synthesize sulphated coumarins and then conjugating algae in which gallic acid-based phenolic compounds have been found. The common feature of these substances is, as with land plants, the ability to absorb radiation from the ultraviolet part of the spectrum and...
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