National Repository of Grey Literature 34 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Alkaloids from the wood of the species Liriodendron tulipifera L. and their activity against human cholinesterases
Hrušková, Magda ; Hošťálková, Anna (advisor) ; Chlebek, Jakub (referee)
Hrušková M.: Alkaloids from the wood of the species Liriodendron tulipifera L. and their activity against human cholinesterase. Diploma thesis, Charles University, Faculty of Pharmacy in Hradec Králové, Department of Pharmaceutical Botany, Hradec Králové, 2018. Key words: Liriodendron tulipifera, alkaloids, biological activity. The alkaloids from the wood of the species Liriodendron tulipifera L. were isolated and their inhibitory activity against acetylcholinesterase, butyrylcholinesterase and propyl oligopeptidase, which are enzymes involved in the pathophysiology of Alzheimer's disease (AD), was investigated. The search and testing of new substances, which are used in AD treatment, is very relevant, as this disease cannot be casually treated yet. An alkaloid extract of Liriodendron tulipifera L. wood was tested in a preliminary testing for inhibitory activity against human cholinesterase. Because of the promising results, it was chosen for an isolation and identification of possible effective alkaloids. The extract was carried out by column chromatography with a step gradient elution. A preparative TLC was used to isolate alkaloids. The identification of alkaloids was done by structural analyses (NMR and MS). Optically active substances were measured for their optical rotation. A modified...
Alkaloids of the family Amaryllidaceae and their biological aktivity I.
Puskásová, Dominika ; Šafratová, Marcela (advisor) ; Chlebek, Jakub (referee)
Puskásová Dominika: Alkaloids of the Amaryllidaceae family and their biological activity I. Diploma thesis 2019. Charles university in Prague, Faculty of Pharmacy in Hradec Králové, Department of Pharmacognosy. The aim of this thesis was to isolate alkaloids from herbal extract, which was obtained from Narcissus pseudonarcissus 'Dutch Master' plant. The preparation and column chromatography of the extract were performed by PharmDr. Daniela Hulcová, Ph.D. as a part of her doctoral study. Using the preparative TLC method, 2 alkaloids marked as No.2.1 and 2.2.2 were isolated from the fraction No.4. Their structure was determined by using the NMR, GC-MS analysis and optical rotation. After comparing the data obtained with literature, the compounds were identified as (+)-homolycorine and (+)-masonine. Both homolycorine and masonine were subsequently subject to testing of inhibitory activity against acetylcholinesterase (AChE), butyrylcholinesterase (BuChE), prolyloligopeptidase (POP) and glycogensynthase kinase 3β (GSK-3β). The activity was expressed as IC50 and was compared to IC50 of the reference substances. Galanthamine (IC50 AChE = 1,7 ± 0,1 μM, IC50 BuChE = 42,3 ± 1,3 μM) and huperzine A (IC50 AChE = 0,033 ± 0,001 μM, IC50 BuChE > 500 μM) were used as standards to compare the inhibitory activity...
Alkaloids of Vinca minor (Apocynaceae) and their biological activities
Klátilová, Anežka ; Cahlíková, Lucie (advisor) ; Chlebek, Jakub (referee)
Charles University Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical botany Candidate: Anežka Klátilová Supervisor: doc. Ing. Lucie Cahlíková Ph. D. Title of diploma thesis: Alcaloids of Vinca minor (Apocynaceae) and their biological activities The aim of this diploma thesis was to process the assigned fraction isolated from the Vinca minor L. plant and to isolate at least one alkaloid to test its biological activity. Using preparative TLC, the alkaloid was sequentially isolated from the fraction, which was then subjected to a structural analysis. NMR and EI-MS methods were used herein. Thanks to these analyzes, the alkaloid was identified as venoterpine. Furthermore, the alkaloid was prepared to test for biological activity. Thus, the isolated alkaloid was identified as venoterpine and tested for biological activity. The observed inhibitory concentration (IC50) to HuAChE and HuBuChe was more than 500 μM, indicating that venoterpine does not rank as a significant inhibitor of cholinesterase. Likewise, the value of cytotoxic activity, when this activity was found to be greater than 10 μM to colorectal cancer cells as well as to healthy cells, is not significant. Key words: Vinca minor, Apocynaceae, alkaloids, biological activities
Alkaloids from wood of the species Liriodendron tulipifera L. and their biological activity
Klíčová, Anna ; Hošťálková, Anna (advisor) ; Chlebek, Jakub (referee)
Klíčová A.: Alkaloids from wood of the species Liriodendron tulipifera L. and their biological activity. Diploma thesis, Charles University, Faculty of Pharmacy in Hradec Králové, Department: Pharmaceutical Botany, Hradec Králové, 2018. Supervisor: PharmDr. Anna Hošťálková, Ph.D. Key words: Liriodendron tulipifera, secondary metabolites, alkaloids, biological activity Alzheimer's disease (AD) is the most common type of dementia. It is neurodegenerative disorder. Patients suffer from cognitive disorder in combination with aphasia, apraxia or disorders of executive functions, which leads to exacerbation of working or social skills. Nowadays, there exist no casual treatment for AD, and that is why the intense research is still waging. Currently there are available remedies, which can slow down progress of AD. These drugs includes also natural substances. An alkaloid extract of Liriodendron tulipifera L. wood showed promising inhibition of human cholinesterases in a preliminary testing. These results were the reason why this extract has been chosen for further isolation of single alkaloids and identification of their biological activity. Isolation was made by column chromatography with step gradient elution. Then was used preparative TLC to isolate single alkaloids. Identification of alkaloids was...
Purification of phlorizin from Malus domestica Borkh. leaves by solid-phase extraction and semi-preparative high performance liquid chromatography.
Prachařová, Eva ; Chlebek, Jakub (advisor) ; Chocholouš, Petr (referee)
DIPLOMA THESIS Purification of phlorizin from Malus domestica Borkh.by solid-phase extraction and semi-preparative high-performance liquid chromatography Eva Prachařová Charles University, Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical Botany The aim of this diploma thesis was to find the best conditions for purification of a flavonoid extract from leaves of Malus domestica Borkh., and obtaining the purest fraction of phlorizin. Phlorizin may be used in the treatment of diabetes mellitus type 2 in the future, it has the ability to reduce glycemia by reducing the absorption of glucose in the small intestine and by increasing urinary glucose excretion. The first step was to find an SPE cartridge with a suitable sorbent and a suitable eluent for solid phase extraction. The DPA-6S cartridge and 100% methanol as an eluentwerefound to be the most suitable for SPE. The next step was to find the best possible conditions for semi-preparative HPLC using an ACE 5 C18 column (5 μm, C18, 150 x 10 mm i.d., 150 mm length). The mobile phase consisted of 1% (v/v) acetic acid in water (solvent A) and ethanol 100% (v/v) (solvent B), and a linear gradient elution was used (10-100% B), 0-60 min, the flow: 1mL/min. This method resulted in the 91.05% purity of phlorizin. Keywords: phlorizin, SPE,...
Alkaloids from the wood of the species Liriodendron tulipifera L. and their activity against human cholinesterases
Hrušková, Magda ; Hošťálková, Anna (advisor) ; Chlebek, Jakub (referee)
Hrušková M.: Alkaloids from the wood of the species Liriodendron tulipifera L. and their activity against human cholinesterase. Diploma thesis, Charles University, Faculty of Pharmacy in Hradec Králové, Department of Pharmaceutical Botany, Hradec Králové, 2018. Key words: Liriodendron tulipifera, alkaloids, biological activity. The alkaloids from the wood of the species Liriodendron tulipifera L. were isolated and their inhibitory activity against acetylcholinesterase, butyrylcholinesterase and propyl oligopeptidase, which are enzymes involved in the pathophysiology of Alzheimer's disease (AD), was investigated. The search and testing of new substances, which are used in AD treatment, is very relevant, as this disease cannot be casually treated yet. An alkaloid extract of Liriodendron tulipifera L. wood was tested in a preliminary testing for inhibitory activity against human cholinesterase. Because of the promising results, it was chosen for an isolation and identification of possible effective alkaloids. The extract was carried out by column chromatography with a step gradient elution. A preparative TLC was used to isolate alkaloids. The identification of alkaloids was done by structural analyses (NMR and MS). Optically active substances were measured for their optical rotation. A modified...
Alkaloids of Papaver rhoeas L. (Papaveraceae) and their biological activity related to Alzheimerʼs disease II.
Čakurdová, Marta ; Chlebek, Jakub (advisor) ; Hošťálková, Anna (referee)
Čakurdová, M.: Alkaloids of Papaver rhoeas L. (Papaveraceae) and their biological activity related to Alzheimer's disease II. Diploma thesis, Charles University in Prague, Faculty of Pharmacy in Hradec Králové, Department of Pharmaceutical Botany and Ecology, Hradec Králové, 2017. The aim of this work was focused on isolation of alkaloids from the fraction 1 (joined fractions 20-27), which was obtained from the summary alkaloid extract of Papaver rhoeas L. (Papaveraceae). The alkaloids were identified by structural analysis NMR, GC-MS, optical activity and melting point. Two alkaloids were identified as (-)-stylopine and (+)-rhoeadine. Isolated substances were tested on ability to inhibit the enzymes acetylcholinesterase, butyrylcholinesterase and prolyloligopeptidase. Obtained data were expressed as IC50 values: (-)-stylopine (IC50 AChE = 522 ± 67 µM, IC50 BuChE = >1000 µM, IC50 POP = >790 µM); (+)-rhoeadine (IC50 AChE = 915 ± 64 µM, IC50 BuChE = >1000 µM, IC50 POP = >790 µM). None of the isolated substances showed so potent cholinesterase inhibitory activity as the alkaloids galanthamine (IC50 AChE = 1.71± 0.065 µM, IC50 BuChE =42.30 ± 1.30 µM) and huperzine A (IC50 AChE = 0.033 ± 0.001 µM, IC50 BuChE = >1000 µM) or rivastigmine (IC50 AChE = 0.037 ± 0.001 µM, IC50 BuChE = 3.3 ± 0.3 nM)....
Study of biological activity of isolated alkaloids from Argemone grandiflora (Papaveraceae)II.
Michal, Vojtěch ; Chlebek, Jakub (advisor) ; Ločárek, Miroslav (referee)
Michal, Vojtěch: STUDY OF BIOLOGICAL ACTIVITY OF ISOLATED ALKALOIDS FROM ARGEMONE GRANDIFLORA (PAPAVERACEAE) II. Diploma thesis 2015. Charles University in Prague, Faculty of Pharmacy in Hradec Králové, Department of Pharmaceutical Botany and Ecology. Supervisor: PharmDr. Jakub Chlebek, PhD. Key words: Argemone grandiflora Sweet, Papaveraceae, alkaloids, isolation, acetylcholinesterase, butyrylcholinesterase, prolyloligopeptidase, Alzheimerʼs disease, in vitro assay. Diethylether alkaloid extract obtained from stem and roots of Argemone grandiflora Sweet was chromatografically analyzed. Using common chromatografic methods, three alkaloids were isolated in clean form. These substances were identified as allocryptopine, (-)-munitagine and (-)-norargemonine by structural analysis (MS, NMR). These obtained alkaloids were tested for their inhibitory activity against human erythrocyte acetylcholinesterase (AChE) and human plasma butyrylcholinestrase (BuChE) by Ellman's method. The results were represented as IC50 values (allocryptopine: IC50 AChE = 250,0 ± 2,52 μM, IC50 BuChE = 530 ± 28,2 μM; (-)-munitagine: IC50 AChE = 62,29 ± 5,81 μM, IC50 BuChE = 837,4 ± 23,03 μM; (-)-norargemonine: IC50 AChE = 205,17 ± 11,6 μM, IC50 BuChE = 4158,20 ± 495,78 μM). Inhibition against prolyloligopeptidase was tested for...
Alkaloids of Papaver rhoeas L. (Papaveraceae) and their biological activity related to Alzheimerʼs disease I.
Bulvová, Leontina ; Chlebek, Jakub (advisor) ; Opletal, Lubomír (referee)
Bulvová, L.: Alkaloids of Papaver rhoeas L. (Papaveraceae) and their biological activity related to Alzheimerʼs disease I. Diploma thesis, Charles University, Faculty of Pharmacy in Hradec Králové, Department of Pharmaceutical Botany and Ecology, Hradec Králové 2017. The aim of this study was to process the summary alkaloidal extract of aerial parts of Papaver rhoeas L.; to isolate contained alkaloids using chromatographical methods; to identify them and to determine their inhibitory activity towards human enzymes acetylcholinesterase, butyrylcholinesterase and prolyloligopeptidase. Two alkaloids (+)-rhoeagenine and LB-2 were isolated, and the structure of LB-2 (its absolute configuration) is being determined nowadays. In vitro biological assays of these alkaloids found the following results: (+)-rhoeagenine (IC50 AChE ˃ 1000 μM, IC50 BuChE = 230 ± 10 μM, IC50 POP = 878 ± 45 μM) and LB-2 (IC50 AChE ˃ 1000 μM, IC50 BuChE = 314 ± 13 μM, IC50 POP = 706 ± 2 μM). The determined IC50 values of isolated alkaloids were compared with inhibitory standards of cholinesterases galanthamine (IC50 AChE = 1,71 ± 0,065 μM, IC50 BuChE = 42,30 ± 1,30 μM), huperzine A (IC50 AChE = 0,033 ± 0,001 μM, IC50 BuChE > 1000 μM, IC50 POP > 1000 μM) and rivastigmine (IC50 AChE = 0,037 ± 0,001 μM, IC50 BuChE = 0,0033 ± 0,0003...
Alkaloids of Narcissus 'Dutch Master' (Amaryllidaceae) and their biological activity III.
Rýdlová, Kateřina ; Chlebek, Jakub (advisor) ; Cahlíková, Lucie (referee)
Rýdlová Kateřina: Alkaloids Narcissus 'Dutch Master' (Amaryllidaceae) and their biological activity III. Diploma thesis 2017. Charles university in Prague, Faculty of Pharmacy in Hradec Králové, Department of Pharmaceutical Botany and Ecology. The aim of this work was isolation of compounds from the selected fraction ND 3 - 5 obtained by column chromatography of a Narcissus 'Dutch Master' alkaloid extract. Preparation of the extract and its column chromatography was performed by Mgr. Daniela Hulcová as a part of her doctoral study. Two substances NDM-1 and NDM-2 were isolated from fraction ND 3 - 5 by column chromatography and preparative TLC. The structures were determined as (+)-masonine and (+)-homolycorine on the basis of NMR, GC-MS analysis, optical rotation and their comparison with literature data. Isolated alkaloids were tested on inhibitory activity against human erythrocyte acetylcholinesterase, plasma butyrylcholinesterase and prolyloligopeptidase. Activity of alkaloids was expressed as IC50 values: (+)-masonine (IC50 AChE = 305 ± 34 μM, IC50 BuChE = 229 ± 24 μM, IC50 POP = 314 ± 34 μM), (+)-homolycorine (IC50 AChE = 63.7 ± 4.3 μM, IC50 BuChE = 151 ± 20 μM, IC50 POP = 173 ± 41 μM). In comparison with standards of galanthamine (IC50 AChE = 1.710 ± 0.1 μM, IC50 BuChE = 42.3 ± 1.3 μM),...

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2 Chlebek, J.
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