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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
101

Deriváty Amaryllidaceae alkaloidů a jejich biologická aktivita: Deriváty tazetinu II / Derivatives of Amaryllidaceae alkaloids and their biological activity: Derivatives of tazettine II

Zelina, Dušan January 2020 (has links)
Charles University Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical Botany Candidate: Dušan Zelina Supervisor: doc. Ing. Lucie Cahlíková, Ph.D. Title of diploma thesis: Derivates of Amaryllidaceae alkaloids and their biological activity: Derivates of tazettine II Plants of family Amaryllidaceae are a rich source of alkaloids that are characterized by a broad biological activity. Perhaps the world's best-known member of this family has become galanthamine, which, because of its potent inhibitory potential, has found a place in the treatment of Alzheimer's disease. Based on the conducted studies, the alkaloid tazettine has been chosen for this thesis. The main purpose was to prepare more active derivatives of tazettine and to test the biological activity for potential use in the treatment of cancer and Alzheimer's disease. Ten aromatic esters of tazettine were prepared. Reaction yields ranged from 33,5-69,3 %. Derivatives were identified by MS, NMR and optical rotation. Prepared compounds were tested for their inhibitory potential against human cholinesterases - AChE and BuChE. Unfortunately, it has not been possible to prepare derivatives, which exhibit significant activity in inhibiting AChE or BuChE. Anti-tumor activity of the derivates has been tested on the panel of selected...
102

Deriváty Amaryllidaceae alkaloidů a jejich biologická aktivita: Deriváty tazettinu I / Derivatives of Amaryllidaceae alkaloids and their biological activity: Derivatives of tazettine I

Pidaný, Filip January 2020 (has links)
Charles University Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical Botany Candidate: Filip Pidaný Supervisor: Assoc. Prof. Ing. Lucie Cahlíková, Ph.D. Title of diploma thesis: Derivatives of Amaryllidaceae alkaloids and their their biological activity: Derivatives of tazettine I A study conducted between 1981 and 2014 found that 65% of small molecule based drugs are related to natural substances. The plants of the family Amaryllidaceae contain a particular and still not fully investigated group of alkaloids called Amaryllidaceae alkaloids. Their important biological effects include, for example, antiviral, antibacterial, antifungal, antiparasitic, cytotoxic and, in particular, motor-neuronal system-mediated effects mediated by inhibition of cholinesterases. A widespread Amaryllidaceae alkaloid is tazettine, a structural type alkaloid of tazettine that has increased interest in the early 1970s due to its cytotoxic acitivity, but appears less interesting in the studies conducted. The subject of this thesis was the preparation of tazettin alkaloid derivatives. The cholinesterase inhibitory activity was then tested. Cytotoxic activity in a panel of selected tumor and healthy cell lines was studied by screening. Unfortunately, none of the derivatives prepared by us showed an...
103

Alkaloidy rodu Narcissus: isolace, strukturní identifikace, biologická aktivita / Alkaloids of genus Narcissus: isolation, structural identification, biological activity

Šimková, Hana January 2021 (has links)
Charles University, Faculty of Pharmacy in Hradec Králové, Department of Pharmaceutical Botany Author: Hana Šimková Supervisor: prof. Ing. Lucie Cahlíková, Ph.D. Title of diploma thesis: Alkaloids of genus Narcissus: isolation, structural identification, biological activity Key words: Narcissus, alkaloids, biological activity, Alzheimer's disease, cytotoxic activity The aim of the diploma thesis was an isolation of alkaloids with a focus on minor fractions. These fractions were obtained from the summary alkaloid extract of Narcissus pseudonarcissus cv. Carlton. The method of preparative TLC was used for the isolation of alkaloids. Three substances of alkaloid origin marked as Fj 3-4/kr, F 7/2-1, F 7/2-3 were isolated from the assigned fractions. These substances were identified as alkaloids of homolycorine type lycorenine, homolycorine and hippeastrine by using GC-MS, NMR and optical rotation. The results were also compared with data in the literature. These three alkaloids were tested for their inhibitory activity against AChE, BuChE, POP and GSK-3β. The inhibitory activity against AChE and BuChE was compared with the reference substances galanthamine (IC50 AChE = 1,71 ± 0,07 μM, IC50 BuChE = 42,3 ± 1,3 μM) and huperzine A (IC50 AChE = 0,033 ± 0,001 μM, IC50 BuChE> 1000 μM). The inhibitory...
104

Alkaloidy Zephyranthes citrina (Amaryllidaceae): izolace, strukturní identifikace, biologická aktivita. / Alkaloids of Zephyranthes citrina (Amaryllidaceae): isolation, identification, biological activity.

Kohelová, Eliška January 2021 (has links)
Charles University, Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical Botany Candidate: Mgr. Eliška Kohelová Supervisor: prof. Ing. Lucie Cahlíková, Ph.D. Title of Doctoral Thesis: Alkaloids of Zephyranthes citrina (Amaryllidaceae): isolation, structure identification, biological activity. Key words: Amaryllidaceae alkaloids, Zephyranthes, Alzheimer's disease, AChE, BuChE, POP, oncological diseases Zephyranthes citrina Baker was chosen, based on result of previous screening study and literatury research, for detailed phytochemical work for the purpose of isolation of the widest range of AAs. From 35 kg of fresh bulbs was obtained 151 g of purified alkaloidal extract, which was processed using column chromatography to almost 700 fractions. These fractions were connected into 27 subfractions, which were processed by liquid-liquid extraction, flash chromatography, preparative TLC and crystallization. Finally, 27 pure alkaloids were isolated. All compounds were identified by MS (EI, ESI), HRMS, 1D- and 2D-NMR, CD, optical rotation and by comparison with literature data. Seven compounds were identified as new undescribed alkaloids (6α-ethoxyhippeastidine, 10-deoxy-6α-ethoxyhippeastidine, narcieliine, zephyjanine, zephycitrine I, 7-ethoxy-10-methoxy-1-methyllycorenane-9-ol a zephycitrin...
105

Alkaloidy rodu Hippeastrum (Amaryllidaceae): izolace, strukturní identifikace, biologická aktivita / Alkaloids of genus Hippeastrum (Amaryllidaceae): isolation, identification, biological activity

Al Shammari, Latifah Ajaj M January 2021 (has links)
Charles University in Prague, Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical Botany Candidate: MSc. Latifah Al Shammari Supervisor: Prof. Ing. Lucie Cahlíková, Ph.D. Title of Doctoral Thesis: Alkaloids of the genus Hippeastrum (Amaryllidaceae): isolation, identification, biological activity. Hippeastrum x hybridum cv. Ferrari was chosen based on results of previous screening studies for detailed phytochemical study for the purpose of isolation of the widest range of AAs. From 25 kg of fresh bulbs was obtained 29,46 g of purified alkaloidal extract, which was processed using column chromatography. Finally, 18 pure alkaloids were isolated including one new homolycorine-type alkaloid (9-O-demethyllycorenine). All compounds were identified by spectrometric techniques (GC-MS, ESI-MS, NMR, optical rotation) and by comparison with literature data. All alkaloids, isolated in sufficient amount, were tested for their biological activities associated with Alzheimer's disease (inhibition of hAChE, hBuChE, and POP), and cytotoxic activity. The inhibitory activity against human cholinesterases was determined in vitro by a modified Ellmanʼs spectrophotometric method. In the hAChE/hBuChE assay, except for 1,2- O,O'-diacetyl-dihydrolycorine which demonstrated a mild hBuChE inhibition potency...
106

Synthesis of Resveratrol Esters and Aliphatic Acids.

Jing, Stanley Mofor 17 December 2011 (has links) (PDF)
Resveratrol (RV) is a naturally occurring phytoalexin of the stilbenoid family produced by some plant species, and present in grape skin, peanuts, and red wine. It has been found to exhibit anti-cancer, anti-inflammatory, anti-viral, anti-aging, cardio protective, and anti-oxidant properties. Bioavailability is a huge setback that limits the potentials of RV. As a result, efforts have been made to design and synthesize RV esters and aliphatic acids in an attempt to increase its bioavailability, solubility in water, and possibly improving its biological activities. Resveratrol esters, 3,5,4'-triacetyloxystilbene (2) and Methyl 1,1',1''- (3,4',5-stilbenyl)-1,6-hexanedioate (3) have been synthesized. Compound 3 is a new compound, synthetic yield is 88%, and purity is above 95% based on NMR integration. Both 2 and 3 are good candidates for biological evaluation. 3 was used as a precursor in the synthesis of resveratrol aliphatic acid, 8-(3',5'-dihydroxylstilbene-4''-oxy)-3,6-dioxocotanoic acid (9). First, 2 was hydrolyzed to resveratrol diester, 3,5-diacetyloxystilbene (4). Mitsunobu reaction of 4 and methyl 8-hydroxy-3,6-dioxooctanoate (7) was then carried out to afford methyl 8-(3',5'-diacetyoxystilben-4''-oxy)-3.6-dioxooctanoate (/5), which was then hydrolyzed to afford 9 in total 43.6 % yield. Structures of all newly synthesized compounds were confirmed by 1H and 13C NMR spectroscopy.
107

Влияние производных 1,2,4-триазинов на ростовые параметры растений : магистерская диссертация / Effect of 1,2,4-triazine derivatives on growth factors plant parameters

Глинских, В. А., Glinskikh, V. A. January 2021 (has links)
В работе представлены результаты исследования влияния производных 1,2,4-триазинов на ранние этапы онтогенеза растений ячменя. Объект исследования – производные 1,2,4-триазины. Охарактеризовано влияние исследуемых веществ на всхожесть семян, параметры роста проростков и активность перекисного окисления липидов. Показано, что исследуемые вещества №2, 6, 10 и 11 проявляют гербицидную активность. Работа изложена на 43 страницах, содержит список использованной литературы из 62 источников, 21 рисунок и 1 таблицу. / The paper presents the results of a study of derivatives of 1,2,4-triazines at the early stages of ontogenesis of barley plants. The object of research is derivatives of 1,2,4-triazines. The influence of the studied substances on the germination of seeds, the parameters of the growth of seedlings and the activity of lipid peroxidation is characterized. It is shown that the investigated substances № 2, 6, 10 and 11 exhibit herbicidal activity. The work is presented on 43 pages, contains a list of used literature from 62 sources, 21 figures and 1 table.
108

Synthesis and Biological Activity of Novel Antimitotic Nucleoside Derivatives of Podophyllotoxin and 4'-Demethylepipodophyllotoxin

Derry, William Brent 08 1900 (has links)
<p> The objective of this study was to synthesize and biologically evaluate a series of novel nucleoside derivatives of the naturally occurring lignans, podophyllotoxin and 4'-demethylepipodophyllotoxin. Epipodophyllotoxin derivatives display two types of biological activity: while the naturally occurring compounds are potent inhibitors of microtubule polymerization, two semi-synthetic glycoside derivatives, viz VP16-213 (etoposide) and VM26 (teniposide), are specific inhibitors of mammalian DNA topoisomerase II. The latter two compounds have proven to be very useful in the treatment of many different types of cancer. In this study, the glycoside moiety of VP16-213/VM26 was replaced with either a thymidine or a 2'-deoxyadenosine group. The synthetic approach involved protective group chemistry, where functional groups on the nucleosides and DMEP were selectively blocked prior to their condensation in the presence of boron trifluoride etherate catalyst. These compounds are of interest because they involve substitution of the glucoside moiety with a nucleoside residue, whose effect on the biological activity of epipodophyllotoxin derivatives has not been examined. The biological activity of these compounds was assessed by examining their cross-resistance patterns towards a set of Chinese hamster ovary mutants resistant to podophyllotoxin VP16-213/VM26, mitotic index, and by a competition assay. From the cross resistance assay, all of the thymidine derivatives were found to be considerably less active than the parent podophyllotoxin and 4'-demethylepipodophyllotoxin molecules, while the 2'-deoxyadenosine derivatives were found to be completely inactive. The cross-resistance patterns of the thymidine derivatives suggests that these compounds display podophyllotoxin-like activity in vivo and show no VP16-213/VM26-like activity. Treatment of wild type cells with the active thymidine derivatives (compounds 1.2, 2.2, 2.3, and 2.4) increased the mitotic indices approximately ten-fold in a dose-dependent manner, which parallels the results of the dose-response curves in the initial cross-resistance assay. Furthermore, there was a marked increase in the levels of drug required to elevate the mitotic index in second-step mutants resistant to podophyllotoxin, again lending support to the initial results indicating that the cellular target of these compounds is tubulin. Only one compound (1.2), was found to out compete the binding of radiolabelled podophyllotoxin to purified calf brain tubulin. However, due to their low activity relative to podophyllotoxin, most of these compounds were insoluble at concentrations required to out compete the binding of radiolabelled podophyllotoxin. Molecular modelling studies have provided useful insights regarding the structure/activity relationships among the active and inactive nucleoside derivatives showing podophyllotoxin-like antimitotic activity. There appears to be steric limits for substituents attached at the C4 moiety that maintain the antimitotic activities of the parent molecules. The electrostatic potential and hydrophobic properties of these groups also seem to play a role in the degree of activity these compounds show, but remain unclear at this point. By simple comparison of the three-dimensional structures of these compounds there appears to be a very limited spacial and electrostatic requirement for the bulky glycosidic moiety attached to C4 which is essential for targeting VP16-213 and VM26 to DNA topoisomerase II. Thus, several important structural features which may distinguish the selectivity POD derivatives show for either tubulin or DNA topoisomerase II are described.</p> / Thesis / Master of Science (MSc)
109

Opioid receptor involvement in the adaptation to motion sickness in Suncus murinus.

Javid, Farideh A., Naylor, Robert J. January 2001 (has links)
No / The aim of the present study was to investigate an opioid receptor involvement in the adaptation response to motion sickness in Suncus murinus. Different groups of animals were treated intraperitoneally with either saline, morphine (0.1 and 1.0 mg/kg), naloxone (1.0, 10.0 and 5.0 mg/kg) or a combination of naloxone plus morphine in the absence or 30 min prior to a horizontal motion stimulus of I Hz and 40 mm amplitude. For the study of adaptation, different groups received saline on the first trial, and in subsequent trials (every 2 days) they received either saline, naloxone (1.0 and 10.0 mg/kg, ip) or morphine (0.1 mg/kg, ip) 30 min prior to the motion stimulus. Pretreatment with morphine caused a dose-related reduction in emesis induced by a single challenge to a motion stimulus. Pretreatment with naloxone alone did not induce emesis in its own right nor did it modify emesis induced by a single challenge to a motion stimulus. However, pretreatment with naloxone (5.0 mg/kg, ip) revealed an emetic response to morphine (P<.001) (1.0 mg/kg, ip) and antagonised the reduction of motion sickness induced by morphine. In animals that received saline or naloxone (1.0 mg/kg), a motion stimulus inducing emesis decreased the responsiveness of animals to a second and subsequent motion stimulus challenge when applied every 2 days for 11 trials. However, the animals receiving naloxone 10.0 mg/kg prior to the second and subsequent challenges showed no significant reduction in the intensity of emesis compared to the first trial. The data are revealing of an emetic potential of morphine when administered in the presence of a naloxone pretreatment. The administration of naloxone is also revealing of an additional inhibitory opioid system whose activation by endogenous opioid(s) may play a role in the adaptation to motion sickness on repeated challenge in S. murinus.
110

Medienos pjaustinio savaiminio kaitimo tyrimai / Research of self‒heating process of osier willows chops

Bušma, Donatas 18 June 2010 (has links)
Darbo tikslas ‒ ištirti drėgnio įtaką susmulkinto gluosninio žilvičio savaiminiam kaitimui ir šilumos sklaidai pjaustinio sampile. Atlikti tyrimai ir literatūros analizė leidžia teigti, kad didelis drėgmės kiekis lemia pjaustinio biologinį aktyvumą, taip pat jo tankį, poringumą ir kitas savybes. Susidaro palankios sąlygos pjaustinio savaiminio kaitimo procesui, kuris siejamas su medienos audinių kvėpavimu, grybų ir bakterijų veikla, biodegradacijos proceso intensyvumu bei medienos pjaustinio savaiminio užsiliepsnojimo rizika. Atlikus tyrimus nustatyta, jog didžiausiu biologiniu aktyvumu (800 ÷ 340 W/(t•h)) pasižymi nuo 50 % iki 33 % drėgnio gluosninio žilvičio pjaustinys. Jam džiūstant toliau, išskiriamas šilumos srautas intensyviai mažėja ir išdžiūvus iki 12 % drėgnio, tampa visiškai biologiškai neaktyvus. Nustatyta, jog medienos pjaustinio temperatūrinis laidis nevienodas įvairuojant jo drėgniui. Temperatūrinio laidžio maksimali vertė 21,6 m2/s fiksuota, kai gluosnių pjaustinio drėgnis siekė 30 %. / The aim of this paper is to explore the influence of humidity to self‒heating and thermal dissipation pile chaff to cut Salicaceae osier. Performed research and analysis of literature suggests that high moisture content determines the biological activity of carving its density, porosity and other properties. It creates favourable conditions for self‒heating process of carving, which is associated with the wood tissue of breath, fungi and bacteria activity, biodegradation process, the intensity of wood carving and the risk of spontaneous ignition. The investigation revealed that the highest biological activity (800 ÷ 340 W/(t•h)) have between 50 % and 33 % of humidity Oyster osier chops. Further drying, heat flow decreases intensively and drying up to 12 % humidity, it is completely becoming biological inactive. It was found that the conductivity of wood carving temperature difference of unequal moisture. Thermal conductivity maximum value of 21,6 m2/s fixed, the willow carving moisture content was 30 %.

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