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Impact of honey enrichment on its antimicrobial activity by bioactive substances against Escherichia coli
ŠEBESTOVÁ, Lucie
The main aim of this bachelor's thesis is to determine the Minimum Inhibitory Concentration (MIC) and the Minimum Bactericidal Concentration (MBC) of both native honeys and honeys enriched with selected essential oils on the growth of Escherichia coli. In the theoretical part of the bachelor's thesis, bacteria Escherichia coli is briefly characterized, including its pathogenic strains and antibiotic resistance. Furthermore, honey is described, including its chemical composition and physiological effects. Additionally, essential oils are generally described, including their antimicrobial properties, along with a brief description of each selected oil. In the methodological part of the bachelor's thesis, procedures for preparing mediums, agar, inoculum, and the determination of their minimum inhibitory and bactericidal concentrations are described. MIC was measured spectrophotometrically in 96 well microtiter plates. MBC was determined by inoculation from the plate onto Mueller-Hinton agar followed by a 24hour incubation. A total of 3 native honeys were tested, which were then enriched with 8 selected essential oils. Essential oils with the addition of dimethyl sulfoxide (DMSO) were also tested. The results of the obtained data are statistically evaluated, graphically presented, and compared with scientific sources.
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Effect of honey fortification by selected bioactive substances on its antimicrobial activity against Staphylococcus aureus.
BOHDALOVÁ, Natálie
Staphylococcus aureus is a Gram-positive bacterium that can cause a wide range of infections, from mild skin infections to serious and life-threatening diseases. One of the main problems associated with this bacterium is still increasing to develop resistance to various types of antibiotics. Honey is a natural product made from the nectar of flowers collected by bees and stored in their combs. Honey has a wide range of ways it can be used for medicinal purposes, thanks to its beneficial effects. The main aim of this bachelor's thesis was to determine the minimum inhibitory and bactericidal concentrations of honeys, whether native or enriched with selected plant essential oils, or the plant essential oils themselves, on the growth of Staphylococcus aureus. The theoretical part focuses on basic information about the bacterium, the diseases it causes, and their treatment. Subsequently, the theoretical part delves into honey and its characteristics. Finally, plant essential oils and their properties are described. The methodological part of this thesis describes the individual tools and instruments that were used. The procedure for the preparation of honeys, plant essential oils and bacterial inoculum is also explained. Finally, the process of determining the minimum inhibitory and bactericidal concentrations is described. The determination of minimum inhibitory and bactericidal concentrations was carried out in 96-well microtiter plates, which were then measured spectrophotometrically. The results showed that the enrichment of honey with bioactive substances has in most cases positive properties on its antimicrobial activity against Staphylococcus aureus.
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Potential microbial hazards in actual cosmetology trends - bio, vegan, raw
Jančíková, Simona ; Skoumalová, Petra (referee) ; Němcová, Andrea (advisor)
Bio-, vegan- and raw-cosmetics are continually more popular type of cosmetic products caused by an absence of synthetic and preservative substances but at the same time there is an increased probability of microbial contamination. The main aim of this thesis is a practical findings of potential microbiological contamination using a challenge test and a determination of any active ingredients in the cosmetic preparations. The legislation of cosmetic preparations as well as the information about certificates, which are awarded for bio-, vegan- and raw-cosmetics has been processed in the theory. This section also discusses a composition of vegetable and essential oils, which are used as raw materials in cosmetics production to a great extent and have a positive effect on skin. This thesis also deals with a possible microbiological contamination, listing the most frequently occurred pathogenic microorganisms, which can have a negative influence on consumer health. Operating life of selected samples using the Schülke Koko test by inoculating selected representatives of bacteria, yeasts and molds (Candida glabrata, Escherichia coli, Pseudomonas aeruginosa and Aspergillus niger) are being tested in the practical part. In addition a possible antimicrobial activity which may partially replace an effect of synthetic preservatives in the presence of essential oils is also being tested. Finally any biological active substances were analysed by the gas chromatography, in particular fatty acids contained in the creams.
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Analysis of sensorially active substances contained herbal extracts
Koloničná, Markéta ; Vítová, Eva (referee) ; Mikulíková, Renata (advisor)
The peppermint (Mentha piperita), the salvia (Salvia officinalis), the lemon balm (Melissa oficinalis), the camomile (Matricaria chamomilla) and the valerian (Valeriana officinalis) are herbs with healing effects. Their ethanol extracts are used for food fortification or in a cosmetic industry. Substances contained in herbal extracts were analyzed in this thesis. The extracts were prepared by maceration. Next, they were analyzed by using a gas chromatography and a mass spectrometry. The aim of this thesis was an optimalization of the method used for the analysis of sensorially active substances. Then, herbal extracts were analyzed and concentration of sensorially active substances was determined.
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Determination of selected substances in phytopharmaceuticals
Hroncová, Michala ; Tulková, Tereza (referee) ; Vávrová, Milada (advisor)
Thyme, linden and cuban oregano are plant that have positive effect of upper respiratory tract infections. The most common are used in the form of teas and syrups. In this thesis were analyzed methods, which are used to specify substances in plants. It describe methods like stem distillation, SPME and GC/MS. The main aim of the thesis was found out subsances, which occur in herbs. Thymol was the substance which was found in every analyzed herb. The thyme contain o-cymen, in mixture of thyme was proofed thymol, borneol, 1-octene- 3- ol, linalol, estragol a 4- terpeneol. The linden has substances estragol a - terpinen. Characteristic substancies od the mixture of linden were o-cymen, estragol a - terpinen. In the cuban oregano were proofed – pinen, camphor, - terpinen. The method SPME was used to analyzed substances in syrup and main substances were thymol a -elemen.
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Pretreatment of hops for further processing in beer technology
Tichá, Anna ; Štursa, Václav (referee) ; Pořízka, Jaromír (advisor)
This diploma thesis deals with pre-treatment of hops for further processing in beer technology. In the experimental part of the work, the effect of low temperatures, as pre-treatment of hops, on the monitored parameters was observed. Three types of cold pretreatment were used. In two cases, the hop material was frozen using a freezer at -25 ° C and in the second case at -70 ° C. In the third case, the hop material was treated by contact with liquid nitrogen in combination with mechanical treatment. The variety of hop materiál was Žatecký poloraný červeňák, which were in the form of pellets or pressed hop cones. The total bitterness of the samples, the total content of phenolic substances, the total content of flavonoids, the antioxidant activity and the concentration of essential oils, specifically myrcene humulene and geraniol, were examined. The effect of pre-treatment was investigated during conventional worth boiling as well as dryhopping. The experimental part includes descriptions of the hopping process, descriptions of individual analytical methods. A parallel measurement was performed on each sample. Significant advantages or disadvantages of some of the pretreatments were not demonstrable, however, the most significant differences were observed in samples hopped with hops pretreated by freezing at -70 ° C, which had a positive effect on the amount of extracted essential oils during cold hops.
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Compounds of terpenic nature in mint plants and the influence of elicitation on them
Jančová, Nikola ; Čáslavský, Josef (referee) ; Vávrová, Milada (advisor)
Diploma thesis is focused on study of compounds of terpenic nature in mint plants. Terpenic compounds are volatile hydrocarbons formed by several isoprenoid units with low molecular weight which cause the typical smell of plants. Presence of these compounds cause that plants seem to be fungicidal, bactericidal and insecticidal. Due to these properties, they can be used as botanical pesticides which are not toxic and no resistant organisms occur. Each plant contains relatively low concentrations of these compounds and therefore elicitors must be used for the increasing of terpenes amount. Elicitors activate defensive mechanisms in the plant leading to higher defense abilities and production of secondary metabolites. The identification and quantification of analytes was determined by gas chromatography in connection with mass spectrometry.
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Preparation and study of selected essential oils
Chmelová, Nikola ; Vítová, Eva (referee) ; Zemanová, Jana (advisor)
The theoretical part of this bachelor thesis is focused on the characteristics, effects and use of essential oils. There are also described methods for isolating essential oils from plant materials, identification options methods suitable for assessing their quality. Within the experimental part essential oils of the Plectranthus amboinicus and Mentha piperita were prepared. Ethanol extraction and automatic hexane extraction using Gerhardt Soxtherm instrument were used for the isolation. The substances occurring in the essential oils made of Plectranthus amboinicus and Mentha piperita were analysed using a gas chromatograph with a mass detector. The aim of this thesis was to find out what potentially allergenic substances are contained in essential oils.
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Koření z čeledi miříkovitých a jejich využití v potravinářském průmyslu
Halodová, Tereza
The diploma thesis "Spices of the Apiaceae Family and Their Use in the Food Processing Industry" focuses on the characteristics of medicinal, aromatic, and spice herbs. The the-sis examines the legislation related to spices, plant substances, and their use in the food processing industry, particularly in the production of essential oils. The thesis also describes the methods of essential oil extraction and the norms for determining their con-tent. The thesis provides a detailed description of the Apiaceae family, which includes significant plant species used as spices. The practical part of the thesis includes a compa-rison and analysis of specific spices from the Apiaceae family, such as Anise, Fennel, Caraway, Dill, and Coriander. The content of essential oils in these spices was determined using the steam distillation method (based on Český lékopis 2017). Samples of the spices were obtained from four different manufacturers. The discovered content of essential oils ranged from 0.66 ml/100 g to 5.26 ml/100 g.
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Využití silic při ochraně bramboru vůči bakterii Dickeya dianthicola
Špaček, Dominik
The thesis "Use of essential oils in the protection of the potato against Dickeya dianthicola" deals with the antibacterial effects of selected essential oils and their components. Specifically, the oils cinnamon, fennel, tea tree, cumin, roman cumin, cloves, tea tree and components of carvone and limonene for the gram-negative bacterium Dickeya dianthicola. Antibacterial activity was assessed using a disc diffusion method where inhibitory zones were monitored. Furthermore, antimicrobial activity was determined using minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC). The disk diffusion method showed that the bacterium tested was most sensitive to the presence of cinnamon oil at all concentrations. Cloves oil was measured to be more efficient at 75 μl/ml than at 100 μl/ml. Based on the MIC and MBC readings, it is clear that the viability of Dickeya dianthicola bacteria was most inhibited by cinnamon essential oil and clove oil. In conclusion, a pathogenicity test was carried out to show that the carvone component suppressed the symptoms of the attack more than the cinnamon and cumin oil.
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