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Analyses of lignans in selected variants of linseed (Linum usitatissimum L.)
DOŠEK, Miroslav
Oilseed flax is one of the traditional agricultural crops. Flax seeds contain, among other beneficial components, lignans, which are polyphenolic substances that provide the plant's defense against biotic and abiotic stress. The main naturally occurring lignan in flax is secoisolariciresinol diglucoside (SDG). Flaxseed represents the richest natural source of lignans, which have been observed to have many positive effects on human health, including antioxidant and other biological activities. One method that can be used to determine SDG is high-performance liquid chromatography with mass spectrometry (HPLC-MS), which was used in this study for the quantitative analysis of SDG. Total polyphenol content (TPC) and antioxidant activity expressed as the ability to quench the DPPH radical were also determined. Correlation analysis was performed to determine the relationships between the studied parameters. Both variety and year had a significant influence on all three studied parameters. The highest average content of polyphenols and SDG was found in the Agram variety, while the highest antioxidant activity was determined in the Floral variety. A significant positive correlation was observed only between the total polyphenol content and the SDG content. The results of this study demonstrate the considerable influence of variety and growing conditions on the content of lignans and the antioxidant potential of flaxseed, which predetermines its health benefits.
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Význam lněného oleje ve výživě
Brettfeldová, Tereza
Bachelor thesis concerns flaxseed oil importance in nutrition. It describes flax plant, which is cultivated to get flax seed with as much oil as possible. Flax seeds can be used either for consumption or for flaxseed oil production. Flax plant is up to 90 cm high. It is sown in spring and is harvested in summer. Flax seeds can be eaten raw or as a sprinkle in pastry, in salads or in drinks. They have a lot of vitamins (vitamins B1, B6, E) and minerals (Cu, Mn, Mg, Fe). Thanks to the high content of fiber and lignans they have positive effect on human body. Fiber positively affects the digestive tract and lignans helps in fight against cancer. Flaxseed oil is made from flax seed by cold pressing. Flaxseed oil can be used in the cold kitchen or as a food supplement. Non-food use can be find for example in the linoleum production, in oil paints or for furniture impregnation. It contains omega-3 unsaturated fatty acid, which is anti-inflammatory, has regenerative effects and lowers LDL cholesterol. Therefore it is good choice to have flaxseed oil as a part of the diet.
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Podophyllotoxin in eastern red cedar (Juniperus virginiana)
Olšar, Jiří ; Siatka, Tomáš (advisor) ; Kastner, Petr (referee)
Charles University Faculty of Pharmacy in Hradec Králové Department of Pharmacognosy Student: Jiří Olšar Supervisor: doc. PharmDr. Tomáš Siatka, CSc. Title of diploma thesis: Podophyllotoxin in eastern red cedar (Juniperus virginiana) This thesis describes the optimisation of the extraction process for quantity determination of podophyllotoxin in the leaves of Juniperus virginiana L. This determination was conducted through three different methods: the extraction in ultrasound bath, the extraction in the orbital shaker and the maceration in cold environment of 4 řC. Extractions were affected by various factors which were monitored, for instance time of extraction, temperature, and extraction solvents. The most efficient method appears to be the extraction in ultrasound bath with the use of methanol or a combination of phosphate buffer with ethyl-acetate.
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Optimalizace GC/MS metody stanovení silyl derivátů lignanů
BEDNÁŘ, Jan
The main goal of this work was optimization of GC-MS method for the analysis of lignans trimethylsilyl (TMSi-) derivatives of two model compounds hydroxymatairesinol(HMR) and enterolactone (ENTL). It included validation of GC-MS metod for TMSiHMR and TMSi-ENTL, comparison of chosen derivatization reagents and verification of time stability for TMSi-HMR. It was shown that TMSi-HMR and TMSi-ENTL provide a nonlinear calibration curve. Second order polynomial curve gave the best fitting and was used for method validation. N-Methyl-N-(trimethylsilyl)trifluoroacetamide activated I and II (Sigma Aldrcih) were selected as the best choice for simultaneous derivatization for HMR and ENTL mixture. Room temperature was confirmed to be appropriat for 3 days storage of TMSi-HMR. Also it was shown that storage at -80 °C preserve the lignan samples for at least 90 days storage.
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Natural sources of lignans in our diet
NĚMEC, Petr
This bachelor thesis deals with lignans (phytoestrogens) in our diet. Preliminary of the work is focused on the characteristic of lignans, which belongs to the not entirely explored group of substances contained in various parts of the plant. The work reviews the most utilized crops (soy, flax, and cereals), from which was isolated a large amount of lignans and other compounds with estrogenic activity. Furthermore, there is introduced the list of substances contained in crops and mechanisms of their action in the human body. Their use is very beneficial in the prevention of serious diseases, so-called civilization. At the end of the work, there are highlighted various methods of separation of lignans from plants.
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