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Encapsulation of natural antioxidants
Štindlová, Jitka ; Obruča, Stanislav (referee) ; Márová, Ivana (advisor)
In theoretical part of this diploma thesis the basic properties of antioxidants, especially anthocyanins and phenolic compounds are described, as well as the basic features and principles of free radicals formation. The theoretical part also describes some possible ways of encapsulation of antioxidants into polysaccharide and lipid particles. In the experimental part basic characteristics of extracts from selected lyophilized fruits and vegetables (carrots, apples and mixed berries) are described. As group parameters of plant extracts the total antioxidant activity, content of flavonoids and phenolics, carotenoids, anthocyanins and ascorbic acid were determined. In experimental part also various encapsulation techniques were tested, encapsulation effectiveness of each technique was evaluated and the stability and size of the created particles were determined. As the best encapsulation method in terms of encapsulation efficiency in most of samples/parameters ethanol injection was found. On the other hand the particles prepared by ethanol injection are relatively unstable in terms of zeta potential, which is followed by their tendency to aggregate. As the most stable particles prepared by thin layer evaporation (TLE) and reverse phase thin layer evaporation (RP-TLE) were evaluated. Particles prepared by TLE, RP-TLE and chitosan-alginate particles exhibited a negative charge, while particles prepared by ethanol injection stayed uncharged and chitosan particles have a positive charge.
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Developement and optimalization of methods for extraction of selected compounds from Hypericum perforatum
Chytil, Dalibor ; Štursa, Václav (referee) ; Pořízka, Jaromír (advisor)
Bachelor's thesis deals with the optimization of processes for extraction of phenolic compounds from St. John´s Wort (Hypericum perforatum). The theoretical part of the work focuses on characterization of this herb, its botanical classification, traditional use, chemical composition and curative effects. Increased attention is further devoted to a theory of preparation of samples for extraction of phenolic compounds and suitable techniques for extraction and characterization of phenolic compounds from extracts of St. John´s Wort. The experimental part of the thesis deals with application of theoretical knowledge. When optimizing the emphasis was on influence of solvent (water acified to pH 4, pH 5, pH 6), influence of extraction technique (ultrasound extraction, subcritical water extraction, maceration) and influence of extraction period (10, 20, 30 min). Extracts were subjected to determination of selected parameters (total phenolic content, total flavonoid content, antioxidant activity) in leaves of St John´s Wort harvested in June 2016 using UV-VIS spectroscopy. The used extraction techniques are significantly different from each other.
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Determination of total antioxidation activity of tea pickles in selected sorts of tea
Bartošová, Jitka ; Vitoulová, Eva (referee) ; RNDr.Jana Skopalová, Ph.D. (advisor)
This thesis deals with the total antioxidant activity (TAA) evaluation of various sorts of tea (green, black, half-fermented, white, mate, rooibos and herbal) depending on the process and time of their treatment. The main emphasis is put on testing a new method of measuring the total antioxidant activity by flow coulometry. The results acquired by this method are compared to the results of the chemiluminescent Trolox equivalent antioxidant capacity (TEAC) method which is a standard for measuring the total antioxidant capacity in various materials and raw materials. The work discusses the reasons for the differences in the values found by both methods.
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Analysis of active substances in honey
Jelénková, Zuzana ; Kubešová,, Jitka (referee) ; Márová, Ivana (advisor)
This diploma thesis was focused on biologically active compounds determination. 26 samples of honey, one sample of propolis and one sample of royal jelly were analyzed. Honey were harvested in year 2006 and 2007 and bought in retail chain, special shops and directly from bee-keeper. Samples were analyzed by titration, spectrofotometry, LC/MS and RP-HPLC methods. The study was focused on analysis of antioxidants. Followed groups of antioxidants were determined: flavonoids, catechins, carotenoids, vitamins E, C, A. Authenticity of quality was determined by hydroxymethylfurfural analysis. Average values of total antioxidant capacity ranged (12.75-137.49) mmol .100 g-1. Average values of total phenolic ranged (8.51-61.34) mg .100 g-1 and average values of total flavonoids ranged (0.75-6.04) mg .100 g-1. Honey samples contained (41.83-585.10) g .100 g-1 of rutin, (9.30-313.40) g .100 g-1 of myricetin, (6.5-171.90) g .100 g-1 of luteolin, (3.19-436.37) g .100 g-1 of quercetin, (2.10-242.66) g .100 g-1 of apigenin, (0.15-105.12) g .100 g-1 of caempferol and (0.07-17.52) mg .100 g-1 of naringenin. From group of catechins there were measured (5.98-310) g .100 g-1 of catechin, (17.77-486.29) g .100 g-1 of epicatechin, (0.18-64.90) g .100 g-1 of catechin gallate and (0.59-140.56) g .100 g-1 of epicatechin gallate. From lipophilic compounds the most abundant in honey samples was tocopherol, its value ranged (29.20-8531.17) g .100 g-1. Content of ascorbic acid ranged (0.65-4.65) mg .100 g-1. Content of hydroxymethyl.furfural. ranged (0.26-4.06) mg .100 g-1. By LC/MS method luteolin, naringenin, protocatechin acid, coffee acid and p-cumaric acid in honeydew were detected and, furthermore, kyanidin and pinocembrin in floral honey were found. Mono-floral honey contained biologically active compounds the most, imperceptibly less contained multi-floral honey and honeydew honey. Acacia honey contained the lowest amount of biologically active compounds.
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Possibility of determination of selected flavonoides
Smělá, Margita ; Vitoulová, Eva (referee) ; Vespalcová, Milena (advisor)
The theoretic part of the bachelor‘s thesis deals with description of selected flavonoids as apigenin, quercetin, luteolin, keampferol, rutin, myricetin and with options of their determinations. There were described typical properities and effects of several flavonoids at first. In the next part there are principles of methods, especially high-performance liquid chromatography and capillary electrophoresis. The biggest attention was made to literary survey of determination flavonoids coumpounds mentioned above, by high-performance liquid chromatography and capillary electroproresis. There were described the collection of plant material for extraction of flavonids in the practical part. The white and blue grapes were frozen by dry ice as soon as they were separated from a busch. Grapes were made in a nitrogenous atmosphere and lyophilizated after the frozen.
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Use of capillary electrophoresis to determine a selected group of flavonoids
Tran Xuan, Tiep ; Mravcová, Ludmila (referee) ; Řezáčová, Veronika (advisor)
In recent years, the use of natural medicinal properties of plants has again come to the forefront of interest of the public. Because of their therapeutic properties, these plants are commonly used in alternative treatments for minor ailments. This thesis deals with the determination of polyphenolic acids in extracts from aronia, echinacea, tetradenia and centella. One of the aims of the thesis was to compare the amount of polyphenolic acids in individual plants with their antioxidant properties. The theoretical part includes a general introduction to flavonoids, introduction to polyphenolic acids, introduction to the principles of capillary zone electrophoresis and a summary of selected foreign studies for the determination of flavonoids. An important chapter of the theoretical part is a description of individual plants with an explanation of their possible therapeutic use. The experimental part is devoted to the process of optimization of electrophoretic determination of selected polyphenolic acids and evaluation of their content. It was found that in the extracts six representatives of polyphenolic acids occur in minimal amounts, often below the limit of quantification or detection of the method.
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Use of rare oils in cosmetics
Pilipenco, Alina ; Szotkowski, Martin (referee) ; Němcová, Andrea (advisor)
The purpose of this bachelor thesis was to research rare oils. The oils from selected plants (poppy, cannabis, thistle) is characterized by the content of active phenolic compounds, fatty acid composition, antioxidant and antimicrobial effects. First part of the thesis is a literary research on a given topic, which contains the following parts: the universal chemical composition of vegetable oils, the characteristics and effects of selected oils and the ways of their obtaining for cosmetic purposes. The experimental part is focused primarily on the basic analysis of selected oil components and the preparation of the shower oil based on the obtained results. In conclusion are presented an overview of all the properties of selected oils, their practical use and assessment of their application in cosmetics.
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Účinky vybraných peptidů na jednobuněčnou řasu Chlamydomonas reinhardtii
Avdeeva, Olga
In the presented work, the modified novicidin peptides NVCAA and NVCHH were applied to the unicellular alga Chlamydomonas reinhardtii. The aim of the study was to determine the minimum inhibitory concentrations of the tested peptides on Escherichia coli bacteria with subsequent application on the unicellular algae Chlamydomonas reinhardtii. The assessment of the effect of the tested peptides on the algae was carried out using spectrophotometric analyses: chlorophyll A and chlorophyll B content, total flavonoid content, total antioxidant capacity and using the DPPH ASSAY method. Chlamydomonas reinhardtii molecular changes were determined by monitoring the amount of isolated RNA and the expression of APX1, APX2, CAT1, CAT2 genes using the Real-time PCR method. Statistically processed data showed that the application of NVCAA and NVCHH peptides induced considerable stress in the cilia.
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Vliv zpracování borůvek na obsah biologicky aktivních látek
Balaščáková, Viktória
This thesis deals with the influence of blueberry processing on the content of bioactive compounds. The aim of the study was to determine and compare the content of bioactive compounds in six types of storage and processing of blueberries. Spectrophotometric analysis was used to determine the content of polyphenols, flavonoids, total antioxidant capacity determined by the TEAC method, and total antioxidant capacity determined by the DPPH method in frozen, oven-dried, freeze-dried, stored at 6 °C, and poorly stored blueberries of the Brigitta variety. The highest content of flavonoids was found in the freeze-dried samples and the lowest content was found in the frozen samples. The highest content of antioxidant capacity determined by the TEAC method was found in the freeze-dried samples. The second highest content of antioxidant capacity by the TEAC method was found in the oven-dried samples. Stored samples in the freezer had the lowest antioxidant capacity content determined by the TEAC method. Samples that were oven-dried had the highest antioxidant properties against free radicals, as determined by the DPPH method. The second-highest content of antioxidant capacity by the DPPH method was found in the freeze-dried samples. Conversely, the lowest value of antioxidant capacity determined by the DPPH method was found in samples frozen at -80°C and -20°C. The difference in values between the freeze-dried and oven-dried samples was very small when determined by the DPPH method. The results indicate that the lyophilization process was identified in this study as the most suitable for preserving bioactive compounds in blueberries.
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Biologicky významné látky v bylinných čajích u čeledi hvězdnicovité
Stejskalová, Lenka
The importance of herbs and herbal teas is a frequently researched topic due to the content of biologically active substances. Plant material is a source of a large number of diverse components, which are proven to have a beneficial effect on the human organism. These substances are able to help in the prevention and possibly treatment of some human diseases. To fully understand the function of individual plants, it is necessary to know the content of individual groups of biologically active substances. The first part of this master's thesis named Biologically Important Substances in Herbal Teas of the Family Asteraceae escribes and defines herbal teas and organic farming. It also describes the Asteraceae family and focuses more specifically on selected species within this family, including marigold (Calendula officinalis), chamomile (Matricaria chamomilla L.), coltsfoot (Tussilago farfara L.) and coneflower (Echinacea purpurea). The consumption of herbal teas is currently high and still growing, therefore it is necessary to know the composition of the used plants. Representatives were chosen for their popularity and abundant use in the preparation of herbal teas. For each representative, there is a short botanical description and description of the contained substances. In the next chapter of the theoretical part, phenolic substances, their determination and effect on human health are presented. The group of flavonoids, which is a subgroup of phenolic substances, is described in more detail. The last section of the theoretical part explains the concepts of antioxidants, free radicals and methods of determining antioxidant activity. These groups were selected for measurement because they are substances showing effect on human health. In the practical part of this work, the total content of polyphenols, the total content of flavonoids and the total antioxidant capacity are determined in selected species. All these groups are determined spectrophotometrically. The essence of this work was to find out whether the content of these compounds in the same in samples from different productions. For each representative, one sample originating from organic farming (known as “BIO“) and one sample originating from conventional agriculture are examined. These two samples were statistically compared.
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