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Development of voltammetric methods for detection of phytosterols on carbon-based electrodes
Zelenský, Michal ; Schwarzová, Karolina (advisor) ; Fischer, Jan (referee)
The aim of this diploma thesis was to develop an electrochemical method for three phytosterols, namely stigmasterol β-sitosterol and ergosterol using voltammetry techniques on glassy carbon electrode and boron doped diamond electrode. The work builds on previous results, where it was shown that the electrochemical oxidation of phytosterols requires perchloric acid in acetonitrile. When this acid is used, a dehydration reaction occurs. Calibration dependences were measured here for all phytosterols in an environment with a water content of 0.43%. The stability of the signal with increasing distilled water content was further investigated. Then the calibration dependences in the increased water content were measured again. If we want to use HPLC-type separation techniques, we must first find out how the phytosterols will behave in this environment, and therefore the signal stability on the buffer content was investigated. The buffers used were phosphate and acetate buffer. Subsequently, the concentration dependence was measured in an environment with a higher content of phosphate buffer. Furthermore, the possibility of detecting two phytosterols at once was investigated. Key words: dehydration, glassy carbon electrode, boron doped diamond electrode, oxidation, phytosterols, voltammetry
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Vliv technologie pěstování kotvičníku zemního (Tribulus terrestris L.) na kvalitu produktu
NEUMANN, Jaroslav
This diploma thesis focuses on the Tribulus terrestris and its cultivation in order to achieve the highest content of biologically active substances. Tribulus has its roots in Chinese traditional medicine and Indian Ayurveda. The monitored substances are protodioscin and diosgenin. These two substances are saponins which are known for many beneficial effects on human health. For example, protodioscin is widely used as a remedy for conception problems. Diosgenin has its use in the fight against cancer. Both of these substances are also used in fitness to increase muscle mass and strength. The most famous is protodioscin, which became famous thanks to the Bulgarian weightlifters. However, the mechanisms of action of protodioscin and, in fact, diosgenin in the human body are not completely known in terms of influencing hormones in our body. In the practical part of this work, acetylsalicylic acid and the commercial preparation NanoFyt Si? are used as an elicitor. Water control was used for control, which was carried out in the same way as elicitor sprays. It is statistically summarized in what concentration the elicitors act or do not act. Based on statistical results, the cultivation procedure is recommended.
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Development of voltammetric methods for detection of phytosterols on carbon-based electrodes
Zelenský, Michal ; Schwarzová, Karolina (advisor) ; Fischer, Jan (referee)
The aim of this diploma thesis was to develop an electrochemical method for three phytosterols, namely stigmasterol β-sitosterol and ergosterol using voltammetry techniques on glassy carbon electrode and boron doped diamond electrode. The work builds on previous results, where it was shown that the electrochemical oxidation of phytosterols requires perchloric acid in acetonitrile. When this acid is used, a dehydration reaction occurs. Calibration dependences were measured here for all phytosterols in an environment with a water content of 0.43%. The stability of the signal with increasing distilled water content was further investigated. Then the calibration dependences in the increased water content were measured again. If we want to use HPLC-type separation techniques, we must first find out how the phytosterols will behave in this environment, and therefore the signal stability on the buffer content was investigated. The buffers used were phosphate and acetate buffer. Subsequently, the concentration dependence was measured in an environment with a higher content of phosphate buffer. Furthermore, the possibility of detecting two phytosterols at once was investigated. Key words: dehydration, glassy carbon electrode, boron doped diamond electrode, oxidation, phytosterols, voltammetry
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Netradiční rostlinné oleje ve výživě člověka a jejich zdravotně preventivní význam
HÁLOVÁ, Karolína
The topis of this thesis is focus on the use of an unconvential plant oils in human nutrition. Oils can be produced in different ways. These are mechanical and physical processes that influence the amount of certain functional substances in oils. These substances are presented for example such as tocopherols, phytosterols, carotenoids and chlorophyll. These oils have a wide range of positive effects on human health. Various studies have shown a connection with the consumption of these oils and the treatment of cardiovascular diseases, cancer, skin diseases and many others. They have also been confirmed to be of no less importance for the development and maintenance of mental activity. This is also the reason why doctors recommended it in connection with pregnancy and subsequent development of children. Unconventional oils significantly reduce LDL cholesterol and increase HDL cholesterol levels. These oils are also used to relieve various types of inflammatory diseases. A significant health preventive effects have been demonstrated, for example, in sea buckthorn oil and safflower oil. The sea buckthorn oil has to treat a wide range of diseases due to the three types of oils with different compositions. Seeds oil is distinctly different of pulp or whole berries oils. Safflower oil is interesting in the treatment of osteoporosis. Consumption of the alternative plant oils is preceded by various civilization diseases.
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Technologie pěstování Kotvičníku zemního (Tribulus terrestris L.) a jeho využití
NEUMANN, Jaroslav
This bachelor thesis is about a plant named Puncturevine (Tribulus terrestris), its substances, which are contained and about its possible usage in medicine. Another chapters describes some substances which we can find in a whole plant. The most important substances are saponins, phytosterols and flavonoids. Saponins are most popular for their aphrodisiatic effects, flavonoids for fighting illnes and phytosterols for decreasing cholesterol in blood plasma. Quantity of these substances is highly dependent on the area where, or how the plant is grown and if elicitors were used. In the practical part I found out if tribulus is known amongst people and how to grow it in greenhouse.
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Extraction of Tall Soap by Use of Selected Organic Solvents
Rousková, Milena ; Heyberger, Aleš
The aim of this study was to compare yields of phytosterols by use of liquid-liquid-extraction when several extraction solvents, recommended in literature sources, were used. Hexane, limonene, isobutanol, methyl isobutyl ketone and methyl tert-butyl ether were tested. These solvents differ in polarity. Largest yields of total phytosterols (67%) and especially of the beta sitosterol (89%) were reached when isobutanol was used. Disadvantages of most of the tested solvents were formation of the undesirable solid interphase, which could not be removed, their partial solubility in water phase and/or their high boiling point.
Fulltext:  PDF
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Effect of pH Adjustment on Hexane Extract Composition at Liquid-Liquid Etraction
Rousková, Milena ; Heyberger, Aleš ; Tříska, Jan ; Cvengroš, J. ; Kleinová, A.
Tall soap is a by-product of the sulphate process in pulp and paper production. In the Czech Republic it is utilized only as an energy source. It can serve also as a source of valuable components, e.g. phytosterols, which have positive effect on human health (decreasing of cholesterol content in blood, cardiovascular diseases, some types of cancer etc.). These substances can be separated by liquid-liquid extraction. Its applicability is limited by high content of emulsifiers in the raw material. It can be eliminated by decreasing the pH of the tall soap solution by mineral acid. This partial acidification has a positive effect on both hydrodynamics of the extraction process and the increase of distribution coefficients of individual compound groups, which can affect the composition of the output phases. Further experiments were carried out to refine phytosterols by the use of wiped-film molecular evaporator. Two different levels of pH of processed tall soap were used.
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Recovery of Phytosterols from Tall Soap Using Liquid-Liquid Extraction
Rousková, Milena ; Heyberger, Aleš ; Tříska, Jan
Tall soap is a side-product in the Kraft process of the paper and pulp production. The most frequently tall soap is processed in paper technology for chemicals recovery and as a fuel. It contains also phytosterols that have medically proved positive effect on human health, especially on cardiovascular diseases and some types of tumour illnesses. Phytosterols can be isolated from the mixture by either energy consuming distillation or by gentle liquid-liquid extraction. The topic of interest is focused on tall soap processing for phytosterols’ yield maximalization by application of special constructed device – vibrating plate extractor.
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Kapalinová extrakce tálového mýdla - studium parametrů v průběhu procesu a jejich vlivu na složení extraktu
Heyberger, Aleš ; Tříska, Jan ; Rousková, Milena ; Růžičková, Kamila ; Volaufová, Eva ; Krtička, M.
Tall soap is most frequently used as an alternative low quality fuel in the paper mills. But after conversion to tall oil (by acidification with sulphuric, hydrochloric or phosphoric acids) it could be processed by extraction separation of fatty and resin acids and neutral compounds, especially phytosterols and/or long-chain aliphatic alcohols. The aim of this study was the investigation of the tall soap liquid-liquid extraction by hexane and the study of the different parameters, especially pH value on the yield of sterols, fatty acids and resin acids.
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