National Repository of Grey Literature 58 records found  1 - 10nextend  jump to record: Search took 0.01 seconds. 
Electrochemical biosensors with spatially separated enzymatic and detection parts for selective analysis in flow-through arrangement
Tvorynska, Sofiia ; Barek, Jiří (advisor) ; Labuda, Ján (referee) ; Korecká, Lucie (referee)
This dissertation thesis presents the newly developed four highly reusable, stable as well as simple, and cost-effective electrochemical (bi)enzymatic biosensors for the selective and reliable determination of choline, acetylcholine, uric acid, and L-lactic acid in flow injection analysis. All biosensors are based on the concept of the spatial separation of the biorecognition part from detection one and amperometric monitoring of the enzymatically consumed oxygen via its four-electron reduction at the highly negative detection potential. In this way, the design of the biosensors includes an easily replaceable enzymatic mini-reactor(s) connected upstream to the flow cell that contains the appropriate silver amalgam-based transducer. The enzymatic mini-reactor based on choline oxidase, uricase, or lactate oxidase was used for choline, uric acid, or L-lactic acid biosensors, respectively. The acetylcholine bienzymatic biosensor includes the consequently connected choline oxidase- and acetylcholinesterase-based mini-reactors. The first part of this thesis focuses on the construction of two different silver amalgam-based electrodes. Specifically, this section discusses the fabrication of a silver solid amalgam electrode covered by mercury film operating in a wall-jet cell and also highlights the...
Alkaloids of Papaver rhoeas L. (Papaveraceae) and their biological activity related to Alzheimerʼs disease VI.
Ludvik, Matěj ; Chlebek, Jakub (advisor) ; Šafratová, Marcela (referee)
Ludvik M., Papaver rhoeas L. (Papaveraceae) alkaloids and their activity related to Alzheimer disease VI., diploma thesis, Charles University, Faculty of Pharmacy in Hradec Králové 2023, number of pages 69. This diploma thesis was focused on alkaloids from combined fractions 13-15 of diethylether extract from Papaver rhoeas L. The methods used for extraction of the alcaloids include flash chromatography and preparative thin-layer chromatography. The structures of isolated compounds were determined by using mass spectrometric and spectrophotometric methods (GC-MS, NMR and optical rotation). Alkaloids were identified as galanthamine and N,N-dimethyltryptamine. Subsequently, N,N-dimethyltryptamine was tested for its biological activity against human cholinesterases, specifically acetylcholinesterase and butyrylcholinesterase. Galanthamine was not tested on ability to inhibit cholinesterase, since the compound has been already tested on this activity at the Department of Pharmacognosy and Pharmaceutical Botany. N,N-dimethyltryptamine showed mild inhibitory activity against butyrylcholinesterase (IC50 = 44,14 ± 1,76) and no activity against acetylcholinesterase (IC50 = >100). Despite its mild activity towards butyrylcholinesterase, N,N-dimethyltryptamine can't be used in therapy of Alzheimer's disease,...
Alkaloids of Papaver rhoeas L. (Papaveraceae) and their biological activity related to Alzheimerʼs disease V.
Dušánková, Zita ; Chlebek, Jakub (advisor) ; Hošťálková, Anna (referee)
Dušánková Z.: Alkaloids of Papaver rhoeas L. (Papaveraceae) and their biological activity related to Alzheimerʼs diesease V.; Diploma thesis, Charles University, Faculty of Pharmacy in Hradec Králové, Department of Pharmacognozy and Pharmaceutical Botany, Hradec Králové 2023, pages 72. The aim of this diploma thesis was focused on isolation of alkaloids from a combined fraction 7-8 of an alkaloidal diethyl ether (Et2O) extract of aerial parts of Papaver rhoeas L. (Papaveraceae). Column chromatography (flash chromatography), planar chromatography (preparative TLC) and crystallization were used for the isolation of alkaloids. The structures of isolated substances were elucidated using NMR, GC-MS methods and optical rotation. Isolated alkaloids were identified as ZD-1, (+)-3,4-dehydrotheaspirone, (±)-juziphine, (+)-lirinidine and protopine. Alkaloids were tested for biological activity against enzymes (acetylcholinesterase, butyrylcolinesterase and prolyl oligopeptidase). (+)-3,4-Dehydrotheaspirone, (±)-juziphine, and protopine did not show significant inhibitory activities against cholinesterases (IC50 values >100 µM). Protopine was also inactive against prolyl oligopeptidase (IC50 >1000 µM ). (+)-Lirinidine showed a moderate inhibitory activity against BuChE (IC50 value of 23,45 ± 0,55 µM), towards...
Synthesis and evaluation of dual acting potential drugs for neurodegenerative diseases
Miffek, Dominik ; Krátký, Martin (advisor) ; Vinšová, Jarmila (referee)
Charles University, Faculty of Pharmacy in Hradec Králové Department of Organic and Bioorganic Chemistry Author: Dominik Miffek Supervisor: doc. PharmDr. Mgr. Martin Krátký, Ph.D. Title of diploma thesis: Synthesis and evaluation of dual acting potential drugs for neurodegenerative diseases Alzheimer's disease (AD) and Parkinson's disease (PD) are neurodegenerative diseases that mainly affect the elderly population. The incidence of these diseases is still increasing worldwide, and currently, there is no cure that can permanently treat patients. Current medications mainly aim to slow the progression of these diseases. The goal is to improve the accessibility of treatment, prevent progression, or completely cure patients suffering from AD and PD. New potential drugs are also developing in this direction, which could exhibit a satisfactory effect in inhibiting cholinesterases. Acetylcholinesterase (ACh) and butyrylcholinesterase (BuChE) play a significant role in the pathogenesis of these diseases. Particularly in Alzheimer's disease (AD), there is a decrease in acetylcholine as a neurotransmitter that ensures the homeostasis and proper functioning of the central nervous system (CNS). In AD treatment, acetylcholinesterase inhibitors (AChEIs) such as rivastigmine, galantamine, and donepezil are used...
Vinca minor L. alkaloids and their biological activity (inhibition of human cholinesterases) V.
Vašíčková, Alžběta ; Chlebek, Jakub (advisor) ; Hošťálková, Anna (referee)
Vašíčková A.: Alkaloids of Vinca minor L. and their biological activity (inhibition of human cholinesterases) V. Diploma thesis, Charles University, Faculty of Pharmacy in Hradec Králové, Department of Pharmaceutical Botany, Hradec Králové 2020. From the selected fraction VM 215-258 were isolated 3 alkaloids by flash chromatography followed, preparative thin layer chromatography and crystallization. Their structure was determined by mass spectroscopy, NMR and optical rotation, and the obtained data were compared with those in literature. Strictamine and minovincinine belong to alkaloids previously isolated, the alkaloid AV-3 has not been isolated yet. These alkaloids were tested for their ability to inhibit human cholinesterases and their inhibitory activity was compared to standards galanthamine and physostigmine. Compound AV-3 showed mild inhibitory activity against BChE (IC50 μM > 86.3 ± 2.3), other alkaloids were considered inactive, their IC50 values against cholinesterases were > 100 μM. Key words: Vinca minor L. (Apocynaceae), vinca alkaloids, minovincinine, strictamine, Alzheimer's disease, acetylcholinesterase, butyrylcholinesterase.
Vinca minor L. alkaloids and their biological activity III.
Valová, Dominika ; Chlebek, Jakub (advisor) ; Hradiská Breiterová, Kateřina (referee)
Valová D.: Vinca minor L. alkaloids and their biological activity III. Diploma thesis, Charles University, Faculty of Pharmacy in Hradec Králové, Department of Pharmaceutical Botany, Hradec Králové, 2020, 75 p. Alzheimer's disease (AD) is a progressive, neurodegenerative disorder and it's the most common form of dementia. Because we're still not able to treat the cause of disease, searching for a new substance is relevant. This thesis is focused on isolation of alkaloids from a Vinca minor L. alkaloidal extract as a potential drug. The preparation and column chromatography of the summary extract were performed by Ing. Miroslav Ločárek as a part of his doctoral studies. Subsequent preparative TLC led to the isolation of three compounds. The chemical structures of the isolated alkaloids were elucidated by means of optical rotation, NMR and MS analyses and by comparison of the obtained data with those in the literature. One of the compounds was determined as(-)-vincine, other two compounds have not been isolated yet. Isolated compounds were also tested for their biological activity. Vincine, DV-1 a DV-3 were tested for their ability to inhibit acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE). Additionally, vincine and DV-3 were also tested for their inhibitory activity on prolyl...
Centaurea cyanus L. (Asteraceae) alkaloids and their biological activity related to Alzheimer's disease
Drabbová, Adriana ; Chlebek, Jakub (advisor) ; Opletal, Lubomír (referee)
Drabbová, A.: Title of Diploma Thesis: Centaurea cyanus L. (Asteraceae) alkaloids and their biological activity related to Alzheimer's disease. Charles University, Faculty of Pharmacy in Hradec Králové, Department of Pharmaceutical Botany, Hradec Králové 2020. Ethyl acetate and chloroform alkaloids extracts were prepared from Centaurea cyanus L. seeds. A novel alkaloid AD-1 (Adrabbin) was isolated from the ethyl acetate extract by common chromatografic methods (column chromatography, preparative TLC). Its structure was elucidated by mass spektrometry, NMR analysis and determination of optical rotation. The alkaloid AD-1 (Adrabbin) possesses a unique structure which consists of a cyclic indole moiety. Also LC-MS analysis of fractions obtained by flash chromatography was performed. In those fractions were detected molecular ions related to compounds previously isolated from other Centaurea species. Alkaloid AD-1 (Adrabbin) was tested on ability to inhibit human cholinesterases, prolyl oligopeptidase and gylcogen synthase kinase 3β. The compound was considered against human cholinesterases inactive (IC50 values > 100 µM). Interestibgly, the alkaloid inhibited prolyl oligopeptidase the same intensity as a standard berberine (AD-1: IC50 143,0 ± 6,0 µM; berberin: IC50 142,0 ± 21,0 µM). The novel compound...
Biological activity of Peganum harmala L. alkaloids and their semi-synthetic derivatives II.
Fejtková, Martina ; Chlebek, Jakub (advisor) ; Cahlíková, Lucie (referee)
Fejtková Martina: Biological activity of Peganum harmala L. alkaloids and their semi-synthetic derivatives II. Diploma thesis 2022. Charles University, Faculty of Pharmacy in Hradec Králové, Department of Pharmacognosy und Pharmaceutical botany. This diploma thesis deals with the preparation of semi-synthetic derivatives of the alkaloid harmine and the study of their biological activity. The alkaloid harmine was isolated by preparative TLC from an alkaloid extract, exactly from its subfraction PH-F1. Semi-synthetic derivatives were prepared by incorporation of different substituents in the N9 position of harmine. For the purposes of this diploma thesis were prepared 17 derivatives, which were subsequently identified on the basis of LC-MS, ESI-HRMS and NMR analysis. After structural elucidation of prepared derivatives, their biological activity was studied. The prepared substances were tested for their inhibitory effect on human acetylcholinesterase (AChE), human butyrylcholinesterase (BuChE), glykogen synthase kinase 3β (GSK-3β) and their cytotoxic activity was also measured on selected tumor and leukemia lines and one healthy cell line. Some of the prepared derivatives showed interesting selective inhibitory potencial against human BuChE, the most active derivative was...
Alkaloids of Papaver rhoeas L. (Papaveraceae) and their biological activity related to Alzheimerʼs disease IV.
Gergely, Eszter ; Chlebek, Jakub (advisor) ; Hradiská Breiterová, Kateřina (referee)
Gergely, E.: Alkaloids of Papaver rhoeas L. (Papaveraceae) and their biological activity related to Alzheimerʼs disease IV. Diploma thesis, Charles University, Faculty of Pharmacy in Hradec Králové, Department of Pharmacognosy and Pharmaceutical Botany, Hradec Králové 2022, 61 pages. A chloroform alkaloid extract of aerial parts of Papaver rhoeas L. (Papaveraceae) showed a significant inhibitory activity on human butyrylcholinesterase (IC50hBuChE = 3,94 ± 0,35 µg/ml) [1,2]. hBuChE represents a key enzyme playing an important role in the pathogenesis of Alzheimer's disease. The main aim of this study was to isolate pure alkaloids by bio-guided assay using flash chromatography and preparative TLC, elucidate their structures (MS, NMR, and optical rotation) and cholinesterase inhibitory activity with Ellman's spectrophotometric method. Prediction of possibility of the molecules' crossing through blood-brain barrier (BBB) via logBB was calculated. Potential non-cytotoxicity of the most active compound was screened on selected nine cancer cell lines and one non-cancer cell line MRC-5. The identified isolated alkaloid (+)-caaverine showed a promising and selective hBuChE inibition (IC50hBuChE = 4,09 ± 0,50 µM and IC50hAChE > 100 µM, respectively) and should be able to cross the BBB (logBB = 0,372) by...
Biological activity of Peganum harmala L. alkaloids and their semi-synthetic derivatives I.
Víchová, Barbora ; Chlebek, Jakub (advisor) ; Křoustková, Jana (referee)
1 ABSTRACT Víchová Barbora: Biological activity of Peganum harmala L. alkaloids and their semi-synthetic derivatives I. Diploma thesis 2022. Charles University, Faculty of Pharmacy in Hradec Králové Department of Pharmacognosy and Pharmaceutical Botany β-Carboline alkaloids are natural substances with potential use in tumor therapy. In particular harmine, which acts cytotoxically by several mechanisms. The aim of the diploma thesis was to prepare N9-derivatives of harmine derivatives, to clarify their structure based on common spectrometric and spectroscopic methods (ESI, ESI-MS, NMR) and subsequently to study their biological activity (cytotoxicity, AChE, BchE and GSk-3beta inhibition). These tests resulted in several active derivatives, suitable candidates for further study. 9-N-(2-nitrobenzyl)harmine (HMA-22) was significantly cytotoxic to the Jurkat cell line (16% cell viability after 48 hours, compared to the control, with better cytotoxicity than the standard doxorubicin at a concentration of 1 μM). Another very active derivative was found 9-N-(5-bromopentyl)harmine (HMA-30), which was more cytotoxic to most tested cell lines than doxorubicin (1 μM), similarly as most of other derivatives. HMA-30 was also found as a potent BChE inhibitor (IC 50 4.06 ± 0.48 μM). 9-N-(4-nitrobenzyl)harmine (HMA-20)...

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