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The antioxidant activity of selected species of small fruit
Křenová, Alena ; Gregor,, Tomáš (referee) ; Diviš, Pavel (advisor)
This diploma´s thesis deals with the determination of total antioxidant activity of red and white gooseberries and red, white and black currants. There are available information about small fruits, an overview of natural and synthetic antioxidants and a summary of the methods to determine the total antioxidant activity in the theoretical part. Frozen fruit samples were provided by Research and Breeding Institute of Pomology Holovousy Ltd. in the project QI111A141 – Research of new technologies in the cultivation of gooseberries and currants with a focus on quality and use of fetuses (Ministry of Agriculture). The total antioxidant activity of red and white gooseberries and currants was measured by spectrophotometric methods using free radicals ABTS•+ and DPPH and was expressed as a Trolox equivalent. The total antioxidant activity of black currants was measured by electron paramagnetic resonance using free radicals ABTS•+ and DPPH and expressed as a TEACABTS and a TEACDPPH. There were measured 8 species of red gooseberries, 6 species of white gooseberries, 12 species of red currants, 6 species of white currants and 8 species of black currants in this thesis. The highest values of total antioxidant activity showed species of red and white gooseberries Alan, Karmen, Pax and Invicta and species of red and white currants Rovada, Orion and Olin. Among black currants, species Ometa and Ruben had the highest values of total antioxidant activity.
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Bioactive substances of rose hip
Ďubašáková, Mária ; Skoumalová, Petra (referee) ; Veselá, Mária (advisor)
The aim of this master´s thesis was to determine the concentration of bioactive substances such as total polyphenols and flavonoids as well as the total antioxidant capacity in tea extracts from Rosa canina. In the second part, an experiment was found to detect antimicrobial activity and an effective concentration of ethanol against selected bacteria. The theoretical part is focused on description of natural antioxidants and their effect on free radicals, description of tea, description of rose hazel and possibilities of spectrophotometric determination of natural substances and eventually basic distribution of bacteria. In the experimental part, ethanol and aqueous extracts were prepared in which the total number of polyphenols, flavonoids and antioxidant effects. The results of the determination of polyphenols and flavonoids show that the solvent with ethanol is more suitable for flower fermentation and water is more suitable for dropping the rose. Comparison of the antioxidant activity of macerates showed no significant differences; slightly higher antioxidant activity showed macerates from pink flowers. The extracts showed antimicrobial activity against Micrococcus luteus and slightly against Bacillus cereus. The highest antimicrobial activity was determined for the micrococcus luteus
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Comparison of an analytical techniques for determination of an antioxidant activity in food
Křenová, Alena ; Vespalcová, Milena (referee) ; Diviš, Pavel (advisor)
This bachelor‘s thesis deals with the characterization of natural and synthetic antioxidants and their effects on free radicals. Natural antioxidants are usually absorbed as a part of complex mixtures and that’s why we try to characterize an antioxidant activity as a whole. Chemical and physical methods have been developed to determine the total antioxidant activity of food. This thesis focuses on chemical methods, specifically on ABTS and DPPH, which are based on a reaction of antioxidants with synthetic radicals. Next chemical method is FRAP, which is based on the reducing ability of antioxidants. In the experimental part, these methods are compared from a perspective of their performance and the results of the analysis of real food samples.
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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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Přirozené antioxidanty v potravinách jako prevence oxidativního stresu v organismu
Kaserová, Natálie
The bachelor thesis is focused on natural antioxidants and their fight against oxidative stress in the organism. The first part is about the oxidative stress, what causes it, and its negative or positive effects on the human body. The connection between free radicals and the development of oxidative stress is outlined. The second part of the literature review is devoted to the antioxidants themselves, both natural and natively occurring in the human organism. The low-molecular organic molecules of plants are described in more detail, which exhibit significant antioxidant activity and constitute a substantial part of our diet. The foods or beverages with high content of antioxidant substances are mentioned in the last part of bachelor thesis. This chapter deals with the foods such as vegetables, fruits, nuts and even cereals. Furthermore, from the beverages are presented the tea, coffee, beer, and wine.
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Assay of fluorescent products in erytrocytes of patients with Alzheimer' s disease
Kohutiar, Matej ; Wilhelm, Jiří (advisor)
Free radicals are highly reactive species with one unpaired electron in orbital. Reactive oxygen and nitrogen species count among important biologic molecules of radical nature. It is very important to fix a concentration of free radicals in cell on non-toxic limits. Products of radical damage are cumulated extra or intracellulary and they are main components of lipofuscin-like pigments. Lipofuscin-like pigments contains in their molecular structure fluorofores, so they are good substrates for fluorescent analysis. Alzheimer's disease is a very actual social and economical problem. Etiology of Alzheimer's disease is still unknown. Histologically, the characteristic presence of Alzheimer's disease is a senil plaques of amyloide ?. ROS and RNS diffuse through hematoencephalic barrier in vessel's lumen and attacks red blood cells. Radical damage of erythrocytes is associated with an increase of concentration of oxidative stress products in cytosol. Sample for fluorescent analysis has been prepared from a red-blood cell extract from 30 patients and 8 healthy controls. Fluorescent spectra of healthy controls have emission maxima in area 327-343nm. In compare with controls, spectra of pacients were more heterogenous in area upon 380nm. The study of oxidative cell damage is important for understanding of...
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The influence of anesthesia on the degree of DNA oxidative damage
Zubáňová, Veronika ; Kuchařová, Monika (advisor) ; Nováková, Veronika (referee)
Background: Oxidative damage is one of the most frequent types of cell components damage leading to oxidation of lipids, proteins and the molecule of DNA. As a consequence, there is a higher occurrence of several pathologies such as atherosclerosis, neurodegenerative diseases, cancer; or diabetes. In our study, influence of whole body anesthesia during minor surgery on the level of DNA damage was examined using comet assay technique. Methods: The basic principle of this method is fixing the cells (lymphocytes) in agarose, their lysis for the removal of membranes, incubation with the specific enzymes and electrophoresis of the released cell nuclei. During the electrophoresis, free low-molecular weight and negatively charged fragments of DNA move towards anode which causes the formation of the typical comet cell shape. Finally, the gels are stained by ethidium bromide (DNA intercalating dye) and visualized. Results: We have observed single strand breakages (SSBs) and, with the use of modified assay using specific enzymes for detection of specific lesions, also oxidized purines and pyrimidines. The extent of DNA damage as determined by the intensity of the tail of the comet was quantified using LUCIA Comet Assay (Laboratory Imaging, Czech Republic) software for image analysis. The results were used...
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The influence of critical condition of patients on DNA damage
Verešpejová, Natália ; Kuchařová, Monika (advisor) ; Bárta, Pavel (referee)
The first cases of patients with pneumonia which grew into an acute respiratory distress syndrome and caused breathing problems began to appear in December 2019. Coronavirus disease 2019 (COVID-19) is the cause of a global pandemic and it is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). A complex interplay of factors is responsible for the progression of the disease. Some studies suggest that it promotes oxidative stress and thus may lead to oxidative damage to cells and DNA. The purpose of this study was to observe the relationship between oxidative DNA damage and a critical condition caused by COVID-19 using a comet assay technique. The basic principle of the used method consists in fixation of lymphocytes in an agarose gel, removal of the membrane and cytoplasm of cells, incubation with specific enzymes and electrophoresis. In the process of electrophoresis, negatively charged DNA fragments migrates towards the anode and the cell thus acquires the typical shape of a comet. Comets are visualized using the DNA intercalation dye ethidium bromide. We quantified single - strand breaks and oxidized pyrimidines and purines by using specific enzymes (modification of the method for detecting specific lesions). Results are reported as % tail DNA, thus the percentage of DNA in the...
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Konverze biologicky aktivních látek při přípravě zelených a černých čajů
Procházková, Anna
This graduation theses deals with the cultivation, processing, preparation of tea and the chemical composition of tea leaves in the theoretical part. Furthermore deals with the synthesis of biologically active substances in plant materials and their conversion from the preparation of tea to the transformation in the human organism after its consumption. It also briefly summarizes and defines the issues of free radicals and antioxidants as part of their functioning in the human body, and then attempts to objectively summarize their main pharmacological effects. The practical part, focused on the determination of phenolic substances and the total antioxidant capacity of selected green and black teas, is supplemented by their sensory analysis.
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