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Hodnocení antifungální aktivity esenciálních olejů prostřednictvím vybraných laboratorních metod
KRATOCHVÍLOVÁ, Viola
The utilization of the antifungal activity of essential oils in the storage of vegetables and food is becoming an increasingly monitored and researched topic currently. The antifungal effects of essential oils offer the possibility of extending the shelf life of food and reducing losses caused by fungi and other microorganisms. These are natu-ral substances that are non-toxic to humans or the environment. Essential oils have recently gained popularity due to their diverse applications, not only in industries such as cosmetics and pharmaceuticals but also in our households. This popularity supports the interest in their use in food as a natural means of reducing fungal occurrence and extending the shelf life of food. The aim of this thesis is to compare the antifungal effectiveness of selected essential oils against isolated microscopic fungi from root vegetables and to compa-re selected methods used for evaluation. The literature review presented in this the-sis summarizes the current knowledge in the area of the antimicrobial effects of essential oils, which offer the possibility of extending the shelf life of food and re-ducing losses caused by fungi and other microorganisms. In the practical part, the four most common morphotypes of microscopic fungi (Fusarium sp., Paecilomyces sp., Trichoderma sp., and Chalaropsis thielavioides) are isolated from root vegeta-bles, which are used in testing the antifungal activity of selected essential oils (ci-tronella, clove, dill, peppermint, cinnamon, and thyme) using the disk diffusion method and the micro-dilution method. The results of the disk diffusion method and the microdilution me-thod slightly differ from each other. The inhibition of essential oils appears slightly higher in the microdilution method, likely due to the presence of volatile com-pounds that more effectively spread within the enclosed space of the microplate, thus exerting a stronger influence on the growth of the tested fungi. However, the three most effective oils are consistent in both methods. Specifically, these are the oils of dill, thyme, and cinnamon. Similarly, the least effective oil is consistent in both methods - peppermint oil.
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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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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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Čerstvost a trvanlivost rybích produktů
HAO, Ruoyi
Fish plays an important role in the human diet and health as a source of easily digestible and highly nutritious animal protein and high value n-3 polyunsaturated fatty acids (n-3 PUFA). However, with high moisture, low amount of connective tissues, and neutral pH value, fish muscle is more perishable than other food muscles. Fish freshness depends on physical, chemical, biochemical, and microbiological changes during the post-mortem, which is crucial to fish quality. Generally, fish muscle deterioration depends on three mechanisms: enzymatic autolysis, lipid or protein oxidation, and microbial growth. The deterioration of fish quality is a complex process affected by the nutrient profile of muscles, microorganisms, storage conditions. Nowadays, a farming culture system of omega-3 carp, enabling the increase of healthy n-3 PUFA in common carp muscle, was developed in the Czech Republic. The benefits of this carp on human health have been proven. However, the knowledge of the potential intervention by the innovative culture system on the nutrients pattern, spoilage process, and freshness of carp is not available yet. Nowadays, chill-stored fish is turning into popular fish food with the encouragement of available cold-chains and promoting healthy consumption concepts of fresh food. Nevertheless, fish quality still deteriorates severely during chilled storage, leading to freshness and shelf-life reduction. The rapid growth and metabolism of microorganisms naturally present or from contamination drive this process. However, recent studies did not comprehensively investigate the microorganisms' role in the freshness reduction of chilled stored fish. Moreover, driven by 'green consumerism', foods with few synthetic additives but more natural ingredients are popular, promoting essential oils (EOs) attracting much attention for fish preservation in recent years. However, the preserving effects of these EOs on fish are inconsistent. Thus, how to establish a good preservation strategy for using EOs-based preservation methods to manipulate microbial spoilage and maintain the freshness of chill-stored fish. This thesis is devoted to filling these knowledge gaps. 1) The patented farming system was found a slight increase in storage stability and shelf-life of carp via the investigation on the differences in the potential nutrients, post-mortem freshness, and shelf life between traditionally cultured common carp and omega-3 carp. 2) The relationships among typical freshness indicators and several dominant spoilage microorganisms and the manipulation of spoilage microorganisms by EOs-based preserving method in chill-stored fish were exposed. 3) A sensory acceptable EOs-based antibacterial coating was developed for the preservation of chill stored fish fillets. 4) Intelligent strategies for maintaining fish gel food freshness and properties via phenolic compounds and ultrasound treatment by enhancing protein cross-linking were established.
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Repelentní účinky silic vybraných rostlinných druhů
Mašláňová, Hana
The summer season is accompanied by an increased incidence of diptera in livestock farming. The insect is a vector of many diseases and in high frequencies reduce milk and meat production. Significant economic losses in cattle breeding are mainly caused by cosmopolitan synanthropic and synbovine species Musca domestica, Stomoxys calcitrans and Haematobia irritatans. An alternative way of controlling insects without negative affecting health and the environment is the application of the herbal preparations containing repellent essential oils. Formulated mixture of essential oils Mentha x piperita, Pelargonium sp. and Nepeta cataria and essential oils Cymbopogon citratus, Cymbopogon nardus and Eucalyptus globulus were able to repel insects for 6 hours with 87% and 73% efficacy on cattle.
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Mechanisms and mode of action of essential oils on fungi
Ježková, Tereza ; Koukol, Ondřej (advisor) ; Čmoková, Adéla (referee)
Essential oils are volatile compounds from plants with a wide range of effects. Many of them exhibit antifungal activity. As the resistance of pathogenic fungi to antimycotics is increasing, finding new antifungal agents for the treatment of fungal infections is highly desirable. In order to use essential oils for the production of new drugs, it is necessary to know the exact mechanism of their action. Although it is known a lot about the effects of essential oils on fungi, the particular target in a cell is not always described. In this thesis I summarize the present knowledge about the mechanisms of actions on fungi. I gradually deal with effects of essential oils on cell wall, plasma membrane, mitochondrion, nucleus, quorum sensing, virulence factors, mycotoxin production and fungal development. Generally essential oils do not act on one structure but affect multiple structures and processes at the same time. In the last chapter I mention possible directions for further research of these substances. Key words: essential oils, fungi, antifungal activity, mechanism of action, mode of action
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Studium účinků směsi esenciálních olejů ve výživě dojnic
Vojkovský, Jiří
The aim of this diploma thesis was evaulating addition of mixture of essential oils into the diet of high yielding cows and its affect on their performance. Cows were divided into 2 groups (P a K), 18 cows in each group. Both groups were fed by the same diet, the only difference was another kind of premin. The diet of group P inclueded mixture of essential oils with dose 1,2 g per cow per day. During the 100 days lasting expe-riment, dry matter intake, milk yield, milk components, rumen fluid and blood composi-tion were monitored. The results were processed and statistically evaluated. The results show conclusive decrease (P < 0,05) of dry matter intake in group P by 0,83 kg.day-1 (3,22 %). The most economic impact is conclusive decrease (P < 0,05) of milk yield in average of 3,72 kg (8,8 %) per cow per day. Simultaneously there was a decrease in milk fat concentration of 12,17 %. On the other hand, the concentration of milk protein was slightly increased in group P.
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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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