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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.
141

Saccharomyces cerevisiae: A Platform for Structure-activity Relationship Analysis and High-throughput Candidate Prioritization

Song, Kyung Tae Kevin 17 July 2013 (has links)
The budding yeast Saccharomyces cerevisiae has been an invaluable model organism in contributing to the current understanding of cellular biology, owing mainly to its highly tractable genetic system and the completion of its genome sequencing in 1996. Indeed, these bolstered the development of novel methods that have provided great insights into genetic and protein networks in human cells. With the large collection of datasets, S. cerevisiae also became an ideal platform for investigating the mechanism of action of novel compounds. The first part of my thesis uses a validated chemogenomic assay to investigate the mechanism of action of structurally related novel DNA-damaging agents, delineating valuable structure-activity relationship in the process. The second part describes the development of a method that uses drug-induced wild-type growth dynamic to characterize novel compounds, which, in combination with the chemogenomic assay, may complement existing high throughput screening experiments to improve the current drug development process.
142

Saccharomyces cerevisiae: A Platform for Structure-activity Relationship Analysis and High-throughput Candidate Prioritization

Song, Kyung Tae Kevin 17 July 2013 (has links)
The budding yeast Saccharomyces cerevisiae has been an invaluable model organism in contributing to the current understanding of cellular biology, owing mainly to its highly tractable genetic system and the completion of its genome sequencing in 1996. Indeed, these bolstered the development of novel methods that have provided great insights into genetic and protein networks in human cells. With the large collection of datasets, S. cerevisiae also became an ideal platform for investigating the mechanism of action of novel compounds. The first part of my thesis uses a validated chemogenomic assay to investigate the mechanism of action of structurally related novel DNA-damaging agents, delineating valuable structure-activity relationship in the process. The second part describes the development of a method that uses drug-induced wild-type growth dynamic to characterize novel compounds, which, in combination with the chemogenomic assay, may complement existing high throughput screening experiments to improve the current drug development process.
143

Étude quantitative du rôle spécifique de glycosaminoglycanes dans le mécanisme d'internalisation de l'homéoprotéine engrailed 2 / Quantitative study of glycosaminoglycan specific role on internalization mecanism of the homeoprotein engrailed 2

Cardon, Sébastien 12 October 2017 (has links)
Les homéoprotéines sont des facteurs de transcription importants au cours du développement des organismes vivants, capables notamment de voyager de cellule en cellule. Ces protéines comportent une longue extrémité N-terminale désordonnée, suivie de trois hélices α séparées par une boucle et un tour. Des études de relations structure-activité ont montré que des domaines cationiques (riches en K et R) particuliers dans ces protéines sont responsables de ces propriétés de transfert cellulaire leur permettant d’être secrétées et internalisées dans les cellules. Ces processus impliquent que ces protéines hydrophiles soient capables de franchir la membrane plasmique composée d'un coeur hydrophobe. La membrane plasmique est en effet composée d’une bicouche lipidique, dans laquelle sont insérées de nombreuses protéines, telles que les protéoglycanes portant des ramifications de glycosaminoglycanes (GAG), polysaccharides anioniques. Dans le but de comprendre au niveau moléculaire le processus d'entrée des homéoprotéines dans des cellules eucaryotes, différentes constructions protéiques ont été produites et étudiées : le peptide pénétrant les cellules correspondant à l'hélice 3 (H3), la séquence correspondant à l'homéodomaine (HD), l'homéodomaine étendu d'une séquence putative de liaison aux GAG (NLS-HD) et la protéine entière (En2). La quantification absolue de l’entrée de ces constructions dans des cellules CHO-K1 par spectrométrie de masse a mis en évidence une efficacité d'entrée meilleure pour H3 > NLS-HD > HD, ainsi que l’importance des GAG de surface dans le processus et plus particulièrement celui des héparanes sulfates (HS). Des expériences complémentaires d’ITC, de dichroïsme circulaire et de RMN ont permis d'identifier deux sites d’interaction avec l’héparine (un site principal de haute affinité et un site secondaire de plus basse affinité), interagissant principalement avec le polysaccharide par interactions électrostatiques. In fine, ces études conduisent à une meilleure compréhension moléculaire du processus d'internalisation des homéoprotéines dans des cellules eucaryotes. / Homeoproteins are important transcription factors during the development of living organisms, and are able to travel from cell to cell. These proteins contain a long N-terminal extremity structurally disordered, followed by three α helices separated by a U-turn. Structure-activity relation studies have shown that in these proteins, some cationic domains (rich in K and R) confer them the cellular transfer properties, allowing them to be secreted by and internalized into cells. These processes imply that the hydrophilic proteins are able to cross plasma membrane. Indeed, the plasma membrane possess a hydrophobic heart and is composed by a lipidic bilayer, in which numerous proteins are inserted, such as proteoglycans carrying glycosaminoglycan (GAG) ramifications, that belong to anionic polysaccharids. In order to understand the entry process of homeoproteins into eukaryotic cells at a molecular level, different proteic constructions have been produced and studied: the cell penetrating peptide corresponding to the third α helix (H3), the sequence corresponding to its homeodomain (HD), the homeodomain with an added putative GAG-binding domain (NLS-HD), and the wild-type protein Engrailed 2 (En2). The absolute mass spectrometry quantification of the peptide and proteins in cells shows a range of internalization efficiency as follows: H3 > NLS - HD > HD. It also highlights the importance of cell-surface GAGs in the internalization and more particularly that of heparan sulfates (HS). Complementary experiments of ITC, circular dichroism and NMR have shown two interaction sites for the heparin (one principal site of high affinity and a secondary site showing a lower affinity) both interacting mainly with polysaccharidic residues using electrostatic interactions. In fine, these studies lead to a better molecular understanding of homeoproteins internalization process in eukaryotic cells.
144

Síntese e determinação da atividade antimicrobiana de 2-[5-nitro-tiofen-2-il]-3-acetil-5-[4-fenil-substituído]-2,3-diidro-1,3,4-oxadiazol frente à cepa ATCC 25923 de Staphylococcus aureus / Synthesis and determination of antimicrobial activity of 2-[5-nitro-thiophen-2-yl]-3-acetyl-5-[4-substitued-phenyl]-3,4-dihydro-1,3,4-oxadiazolines against ATCC 25923 Staphylococcus aureus strain

Leonardo Viana de Almeida 12 February 2009 (has links)
A introdução de um grupo substituinte na molécula de um fármaco promove alterações químico-estruturais que, por sua vez, modificam suas propriedades físicoquímicas. O arranjo espacial de átomos ou grupos de átomos, em especial grupos funcionais, na molécula de um fármaco, expressos por meio de suas propriedades físico-químicas, influenciam direta ou indiretamente na interação fármaco-receptor. Esta, por sua vez, determina aspectos farmacológicos e farmacocinéticos que influem na eficácia terapêutica do medicamento. Assim, uma série de compostos 2-[5-nitro-tiofen-2-il]-3-acetil-5-[4-fenil-substituído]-2,3-diidro-1,3,4-oxadiazolínicos foi planejada e os análogos foram sintetizados, identificados estruturalmente e avaliados in vitro quanto a atividade antimicrobiana frente a Staphylococcus aureus (cepa ATCC 25923), expressa pela determinação da concentração inibitória mínima. Cepas desta bactéria são comuns em infecções hospitalares e frequentemente apresentam caráter de multi-resistência, portanto, alternativas aos fármacos comumente empregados na terapia antibacteriana, especialmente em infecções multi-resitentes, são alvo de estudos e desenvolvimento. Relações entre mudanças estruturais de 2-[5-nitro-tiofen-2-il]-3-acetil-5-[4- fenil-substituído]-2,3-diidro-1,3,4-oxadiazolinas e suas respectivas concentrações inibitórias mínimas podem fornecer informações sobre a influência de propriedades físico-químicas na ação antibacteriana destes compostos, informações estas que podem contribuir para o entendimento das relações entre a estrutura química e a atividade biológica desta classe de compostos, visando a identificação qualitativa e quantitativa das propriedades físico-químicas que influenciam no perfil farmacológico desta classe de compostos. Os grupos substituintes introduzidos nos derivados de 2,3-diidro-1,3,4-oxadizolinas-2,3,5-substituídas contribuem para alterações em suas propriedades físico-químicas, sendo representadas por parâmetros físico-químicos que descrevem a natureza e intensidade da alteração observada. O presente trabalho objetivou identificar, partindo das propriedades físico-químicas, fatores da estrutura química que favoreçam a atividade antimicrobiana dos compostos estudados. A atividade antimicrobiana, expressa pela concentração inibitória mínima, foi determinada pelo procedimento de microdiluição sucessiva, no qual diferentes concentrações de composto a ser analisado foram incubadas em presença de inóculo de Staphylococcus aureus, em meio de cultura líquido. As microdiluições originam concentrações decrescentes a fim de se determinar a menor concentração do composto testado onde o crescimento microbiano foi inibido. Foram realizadas comparações entre as concentrações inibitórias mínimas dos compostos analisados e destas com parâmetros estruturais que representam as propriedades físico-químicas dos compostos. Baseado nas análises comparativas, identificou-se tendências que evidenciam a preponderância de propriedades físicoquímicas sobre a atividade antimicrobiana desempenhada. Constatou-se que a hidrofobicidade influi significativamente na atividade antimicrobiana. Observou-se também que o efeito eletrônico por indução e o volume do grupo substituinte em posição para-fenila também influenciam a ação antimicrobiana, mas estas ainda não foram conclusivas, carecendo de estudos mais aprofundados que levem à compreensão dos fatores estruturais que mais influenciam a ação antimicrobiana de 2-[5-nitro-tiofen-2-il]-3-acetil-5-[4-fenilsubstituído]- 2,3-diidro-1,3,4-oxadiazolinas, de forma a fundamentar o planejamento de futuros candidatos a fármacos antimicrobianos a partir desta classe de compostos. / The introduction of a substitute group within a drug molecule promotes chemical-structure shifts, which by consequence, alters its physical-chemical properties. The atomic special design, particularly the one related to functional groups, assumed in a drug molecule, expressed by the physical-chemical properties, interferers directly or indirectly on drug-receptor interaction. Theses effects collaborate to pharmacologic and pharmacokinetics aspects of drugs, interfering with its therapeutic efficient. Therefore, a set of 2-[5-nitro-thiophen-2-yl]-3-acetyl-5-[4- substitued-phenyl]-3,4-dihydro-1,3,4-oxadiazolines compounds was designed and its analogs synthesized, structurally identified, and in vitro assayed due to its antimicrobial activity against ATCC 25923 Staphylococcus aureus strains, through the determination of minimum inhibitory concentration. Strains of such bacterial species are commonly present within hospital infections, and frequently appear as multi-resistant variant. Consequently, alternatives to the agents usually applied in antimicrobial chemotherapy, particularly to multi-resistant infections, are target for drug research and development. Relations among structural shifts on 2-[5-nitro-thiophen-2-yl]-3-acetyl-5-[4-substitued-phenyl]-3,4-dihydro-1,3,4-oxadiazolines compounds and its respective minimum inhibitory concentration may lead to information about the influence of physical-chemical properties in antimicrobial activity. Continually, such information might contribute to the elucidation of chemical structure-biological activity relationship of these compounds. The substitutes groups inserted on 2,3,5-substituted-3,4-dihydro-1,3,4-oxadiazolines derivates contribute to differs the molecule physical-chemical properties, which is represented by its physical-chemical parameters, which describe the nature and intensity of the observed modification. Therefore, the following study aimed to identify, throughout physical-chemical properties, chemical structure factors that favor the antimicrobial activity of the synthesized compounds. The antibacterial activity, expressed as the minimum inhibitory concentration, was quantified by the microdilution method, where gradual concentrations of the tested conpound were incubated within ATCC 25923 Staphylococcus aureus cells suspended in broth medium. The microdilutions originated descending concentrations, in order to spot the minimum concentration whose microbial growth was inhibited. The minimum inhibitory concentration regarded to each compound was correlated to its physical-chemical parameters. Based on observed relations, it could be identified evidences assuming the physical-chemical properties relevance on antimicrobial assay. It was verified that hydrophobic effects interferes with antimicrobial activity, as well as inductive electronic effects and molecular volume of substitute group in para-phenyl position. These factors contribute to physical-chemical properties shifts and therefore play a role on the antimicrobial action. However, these latest two influences were enable to conclude, suggesting the need of more extensive studies. So that, a more profound comprehension about structure factors that interfere with 2,3,5-substitued-3,4-dihydro-1,3,4-oxadiazolines derivates might lead to the rational design of potential antimicrobial agents among this class of compounds.
145

Système VEGF/VEGFR : conception et évaluation de molécules ciblées et régulation potentielle par les métaux / VEGF/VEGFR system : design and evaluation of targeted compounds and possible regulation by transition metals

Reille-Seroussi, Marie 24 September 2014 (has links)
Dans les thérapies anticancéreuses, les traitements anti-angiogéniques agissant sur l’axe VEGF/VEGFR ont une place importante en clinique. Dans ce contexte, nous avons conçu et évalué l’activité de nouveaux inhibiteurs de l’interaction VEGF/VEGFR. Une première approche a été la conception de molécules antagonistes du VEGFR1. Différents analogues hétérocycliques dérivant d’un composé de type (3-carboxy-2-ureido) thiophène ont été synthétisés. Des réactivités chimiques intéressantes ont été mises en évidence, mais l’activité biochimique de ces molécules ne s’est pas révélée concluante. Une seconde approche reposant sur la conception de peptides ciblant le VEGF a alors été initiée. A partir d’un peptide cyclique connu de 19 résidus ayant une affinité submicromolaire pour le VEGF, de nouveaux peptides et peptidomimétiques ont été développés.L’objectif a été de concevoir des composés de structures chimiques potentiellement plus simples et plus stables en milieu biologique, tout en optimisant l’affinité pour le VEGF. L’interaction de ces peptides avec le VEGF a été étudiée in vitro par ELISA et ITC, ainsi que par cristallographie pour le composé le plus affin. En parallèle, nous avons étudié l’effet du cuivre et d’autres métaux divalents sur l’interaction VEGF/VEGFR1. Au travers d’expériences réalisées au laboratoire ainsi qu’en collaboration, nous avons montré que certains métaux étaient capables non seulement d’inhiber l’interaction VEGF/VEGFR1 mais également d’induire une dimérisation non classique du domaine 2du récepteur. Sachant que les métaux, et en particulier le cuivre, sont connus pour jouer un rôle important dans l’angiogenèse, cette découverte apporte de nouveaux éléments de réponse sur leur mécanisme d’action. Ce travail de thèse s’inscrit donc non seulement dans une démarche de développement de nouveaux composés anti-angiogéniques mais également de compréhension du mécanisme de régulation de l’angiogenèse. / Inhibiting angiogenesis is an effective strategy of targeting therapy against cancer. In thiscontext, we develop an antiangiogenic strategy consisting in the design and evaluation of compoundsblocking the VEGF/VEGFR interaction. The first approach was the conception of antagonists of theVEGFR1. Starting from a (3-carboxy-2-ureido) thiophene hit, a variety of heterocyclic analogs wasdeveloped. Interesting chemical observations were made during the synthesis, but no optimization ofthe biochemical activity was achieved. The second approach was the design of peptides that bind tothe receptor-recognition surface of the VEGF. Starting from a cyclic peptide known to bind to theVEGF with a sub-micromolar affinity, new peptides and peptidomimetics were developed. Thestrategy was to design simplified and potentially more stable compounds, and to improve at thesame time the VEGF affinity. The interaction of VEGF with these ligands was studied in vitro by ELISAand ITC experiments, as well as X-ray diffraction for the best compound. Moreover, the investigationof the effects of copper and other divalent metals on the VEGF/VEGFR1 interaction was undertaken.Experiments realized in the laboratory and in collaboration showed that metals were able to displacethe VEGF/VEGFR1 interaction and to induce the dimerisation of the domain 2 of the receptor. Metalsare well known to play an important role in angiogenic phenomena, but their specific targets are stilla matter of debate. In this context, this discovery brings new response elements regarding theirmechanisms of action. Therefore, the objectives of this PhD thesis were the development of newantiangiogenic compounds, as well as the understanding of some aspects of the regulation of angiogenesis.
146

Synthèse et évaluation biologique de composés de série pyranodibenzofurane actifs sur Mycobacterium Tuberculosis / Synthesis and biological activity of pyranodibenzofurane series compounds with antitubercular activity

Khouri, Inana Marie 29 November 2012 (has links)
La tuberculose est une maladie infectieuse extrêmement contagieuse qui dans sa forme simple peut être soignée et guérie. Cependant, des formes multirésistantes aux traitements classiques ont récemment fait leur apparition et le développement de nouvelles molécules constitue donc un enjeu majeur de santé publique. Le 3,3-diméthyl-1,2-dihydro-3H-benzofuro[3,2-f][1]benzopyrane est un produit possédant une activité antituberculeuse marquée, y compris sur des lignées résistantes. L’objectif des travaux réalisés ici est la recherche de composés de puissance accrue et l’élucidation du mécanisme d’action de cette série. Dans une première partie, des modifications structurales portant sur le cycle A sont présentées. Les résultats des tests biologiques ont permis de sélectionner des composés qui possèdent un index de sélectivité favorable entre l’activité antituberculeuse et la toxicité. Un composé de structure linéaire a également montré un profil d’activité intéressant. Les études de mécanisme d’action ont mis en évidence que les composés synthétisés affectent les synthèses des époxy-mycolates ainsi que celle des α-mycolates de la paroi cellulaire. Dans une deuxième partie l’influence des groupements en position 3 du 3,3-diméthyl-1,2-dihydro-3H-benzofuro[3,2-f][1]benzopyrane a été étudiée. Des composés possédants des chaines de longueur croissante en cette position ont été synthétisés. L’activité antituberculeuse des premiers produits obtenus, a été mesurée et a montré une importante influence du type de chaine introduit sur l’activité biologique. Les études présentées dans ce travail ont donc permis d’une part de préciser la cible cellulaire de ces molécules et d’autre part de sélectionner des composés peu cytotoxiques. / Tuberculosis is a highly contagious infectious disease which can be treated and cured in its simple form. However, multidrug resistant forms towards classic treatments have recently appeared and the development of new drugs is a major challenge for public health. The 3,3-dimethyl-1,2-dihydro-3H-benzofuro[3,2-f][1]benzopyran have a significant anti-TB activity, including resistant lines. The goal of this work is the research of more active compounds and the elucidation of the mechanism of action of this series. In a first part, modifications are introduced on A ring. The results of biological tests were permitted to select compounds that have a favorable selectivity index between tuberculosis activity and toxicity. A linear compound has also showed an interesting activity. Studies on mycolates biosynthesis revealed that the synthesized compounds affect the synthesis of epoxy-mycolates and α-mycolates of the cell wall. In the second part of this work the influence of groups introduced at position 3 of 3,3-dimethyl-1 ,2-dihydro-3H-benzofuro[3,2-f][1]benzopyran was studied. Compounds possessing different length chains at this position have been synthesized. Anti-TB activity of the first products obtained was measured and showed a significant influence of the type of chain introduced. The studies presented in this work permitted to define the cellular target of these compounds and on the other hand to select the compounds with lowest cytotoxicity.
147

Vývoj elektrochemických metod k studiu antibakteriálních látek v malých objemech / Development of electrochemical methods for study of antibacterial compounds in small volumes

Gajdár, Július January 2019 (has links)
Main goal of this Ph.D. thesis is to develop voltammetric methods for the electrochemical study of novel antimycobacterial compounds hydroxynaphthalene- carboxamides. Firstly, this study was focused on the miniaturization of voltammetric methods and construction of an electrochemical microcell due to usually small volume of samples that are associated with an analysis of biologically active compounds in biological matrices. Therefore, all aspects of the voltammetric procedure were studied in a relation to miniaturization. Microcells were based on commercially available electrodes: glassy carbon electrode as a reliable electrode material with well-described characteristics and a novel silver solid amalgam electrode. This study was carried out with analytes 4-nitrophenol, pesticide difenzoquat, and 1-hydroxy-N-(4-nitrophenyl)naphthalene-2-carboxamide. Attention was paid especially to the optimization of oxygen removal procedures in the drop of a solution. Developed miniaturized methods had the same parameters for the determination of studied compounds as in bigger volumes. The proposed electrochemical microcell can be generally used for voltammetric analysis of those samples of biological or environmental origin that are usually available in very limited volumes. Second part of the thesis was focused...
148

In silico određivanje fizičko-hemijskih, farmakokinetskih i toksikoloških parametara i in vitro ispitivanje antiproliferativne aktivnosti novosintetisanih derivata N-sukcinimida / In silico physico-chemical, pharmacokinetic and toxicologic parameters determination and in vitro antiproliferative activity evaluation of newly synthesized succinimide derivatives

Ćurčić Jelena 30 July 2020 (has links)
<p>Sukcinimidi su jedinjenja koja pokazuju vi&scaron;estruke farmakolo&scaron;ke efekte uključujući i antiproliferativnu aktivnost, zahvaljujući prisustvu farmakofore sa dva hidrofobna regiona i dva regiona bogata elektronima. Savremeni dizajn lekova ima za cilj da se modifikacijama u strukturi (promena vrste, položaja i orijentacije supstituenata) i in silico računarskim metodama predvide i optimizuju farmakokinetske osobine i bezbednosni profil kandidata za lek. U ranoj fazi razvoja lekova se koriste postojeće baze podataka o molekulskim, farmakokinetskim i toksikolo&scaron;kim parametrima već ispitanih jedinjenja i pomoću matematičkih modela i algoritama predviđaju se osobine novih molekula, elimini&scaron;u se neodgovarajući kandidati i postiže se u&scaron;teda u vremenu i materijalnim sredstvima. Da se ispitaju fizičko-hemijske karakteristike 11 novosintetisanih metil-etil-N-aril-sukcinimida na osnovu strukture, primenom različitih softverskih paketa; da se na osnovu strukture odrede farmakokinetski i toksikolo&scaron;ki parametri, primenom različitih softverskih paketa; da se ispita retenciono pona&scaron;anje, odnosno odrede retencione konstante za svako jedinjenje primenom visokoefikasne hromatografije na tankom sloju (HP-TLC) i ispita mogućnost primene retencionih konstanti kao mere lipofilnosti ispitivanih jedinjenja; da se ispita antiproliferativna aktivnost na odabranim kulturama ćelija karcinoma i na zdravim ćelijama fibroblasta pluća; da se analizom molekulskog dokinga ustanovi vezivanje za estrogene receptore. Ispitano je retenciono pona&scaron;anje 11 novosintetisanih derivata sukcinimida primenom visokoefikasne hromatografije na tankom sloju (HP-TLC) obrnute faze uz primenu dvokomponentne sme&scaron;e vode i organskog rastvarača (metanola, acetonitrila ili acetona), sa odgovarajućim zapreminskim udelom organskog rastvarača kao mobilne faze. Iz razvijenih hromatograma su izračunate retencione konstante RM0 i S. Logaritam podeonog koeficijenta (logP) određen je in silico, kori&scaron;ćenjem različitih računarskih programa. In silico su određene fizičko-hemijske karakteristike, farmakokinetski parametri, toksikolo&scaron;ki parametri, akvatična toksičnosti i afinitet vezivanja za estrogene receptore. Izračunate su vrednosti afiniteta za 4 vrste receptora (G-protein spregnuti receptori, jonski kanali, inhibitori kinaza, nuklearni receptori). Antiproliferativna aktivnost ispitivanih derivata sukcinimida određena je primenom kolorimetrijskog testa sa tetrazolijum solima (MTT testa) na komercijalnim kulturama ćelija (MRC-5, A549, HeLa, MDA-MB-231, MCF-7, HT-29) i izračunate su IC50 vrednosti. Urađena je i doking analiza sukcinimida prema ERA (estrogen receptor alfa) i ERB (estrogen receptor beta) i dobijene su vrednosti energije formiranja kompleksa sa posmatranim receptorima (MolDock Score). Statistički najznačajnije linearne korelacije dobijene su između eksperimentalno određenih hromatografskih parametara (RM0 i S) i in silico parametara lipofilnosti MlogP i ClogP. Ispitivanjem uticaja promene RM0 i S na farmakokinetske karakteristike dobijeni su rezultati koji pokazuju paraboličnu zavisnost konstante apsorpcije (Ka) i procenta vezivanja za proteine plazme (PPB) od posmatranih retencionih konstanti, dok je zavisnost sa volumenom distribucije (Vd) i sposobno&scaron;ću prolaska kroz krvno-moždanu barijeru (logBBB) bila linearnog tipa. Toksičnost ispitivanih jedinjenja, procenjena na osnovu in silico dobijenih LD50 vrednosti, nije bila vi&scaron;a od toksičnosti već registrovanih lekova sa strukturom sukcinimida, i dala je parabolične zavisnosti u odnosu na RM0 i S vrednosti. Eksperimentalno nijedno od ispitivanih jedinjenja nije pokazalo aktivnost u odnosu na zdrave fibroblaste pluća. Najznačajniju antiproliferativnu aktivnost (najniže IC50) su pokazala jedinjenja 6 i 7 u odnosu na ćelije linije MCF-7 i jedinjenje 11 u odnosu na A549 ćelijsku liniju. Doking analiza je pokazala niže energije formiranja kompleksa sa ERA, u odnosu na ERB. Eksperimentalno određeni parametri RM0 i S se mogu koristiti kao alternativne i pouzdane mere lipofilnosti analiziranih sukcinimida. Ispitivana jedinjenja pokazuju povoljne fizičko-hemijske karakteristike, predviđene in silico metodama i povoljne farmakokinetske karakteristike: male vrednosti konstante apsorpcije, umeren volumen distribucije, povoljan afinitet vezivanja za proteine plazme, favorizovan prolazak kroz krvno-moždanu barijeru za lipofilnija jedinjenja. Procenjuje se da sva ispitivana jedinjenja, izuzev derivata sa &ndash;CN supstituentom, imaju zahtevani nizak stepen toksičnosti. Po antiproliferativnoj aktivnosti u odnosu na ćelije ER-zavisnog karcinoma dojke (MCF-7) izdvajaju se jedinjenja sa metil i nitro supstituentom u para položaju. Na osnovu malih energija formiranja kompleksa sa ERA, koji su eksprimirani na ćelijama MCF-7 linije, pretpostavlja se da bi mehanizam njihovog delovanja delimično mogao biti obja&scaron;njen uticajem na ERA, ali su potrebna dodatna istraživanja na tom polju.</p> / <p>Succinimides have exhibited various pharmaceutical effects including antiproliferative activity due to an important structural fragment (a pharmacophore) presented in form of two hydrophobic regions and two electron-rich centers. Current development of new drugs involves modifications in structure (type, position and orientation of substituents) and usage of in silico computational programs to predict and optimize pharmacokinetic and safety profile of drug candidates. In early phase of drug development, databases regarding the molecular, pharmacokinetic and toxicological parameters of already tested compounds are used, mathematical models and algorithms are applied for predicting the properties of new molecules and inadequate candidates are eliminated saving time and resources. Determination of physico-chemical properties of the analyzed methyl-ethyl-N-phenilsuccinimide derivatives by software packages; virtual pharmacokinetic and toxicology screening; investigation of retention behavior of the compounds by the reversed-phase HPTLC analysis and calculation of retention constants and their correlation with lipophilicity; in vitro evaluation of antiproliferative activity toward five carcinoma cell lines and normal fetal lung cell line; molecular behavior study on target estrogen receptors by molecular docking and correlation of antiproliferative activity toward ER+ breast carcinoma cell lines and in silico estrogen receptor affinity binding. Retention behavior of 11 newly synthesized succinimide derivatives was determined by reversed phase high performance thin layer chromatography (RP HPTLC) with the application of two-component mixtures water - organic solvent (methanol, acetonitrile or acetone) with adequate volume fractions of the organic modifier. After chromatographic development RM0 and S parameters were calculated. The logarithm of partition coefficient, logP for the analyzed compounds were calculated by different softwares. Physico-chemical properties, pharmacokinetic and toxicological parameters, aquatic toxicity and relative affinity to estrogen receptors were predicted in silico. The affinity toward 4 types of receptors (G-proteine coupled receptors, ion channels, kinase inhibitors, nuclear receptors) were calculated as well. Standard MTT assay was applied to evaluate cytotoxic activities of the analyzed succinimides after cells were exposed. Antiproliferative activity were investigated toward commercial MRC-5, A549, HeLa, MDA-MB-231, MCF-7, HT-29 cell lines and IC50 values were calculated for each compound. MolDock Score that represents energy of binding to estrogen alfa and estrogen beta receptors was determined by molecular docking. Statistically significant linear correlations were determined between the chromatographic retention constants (RM0 and S) and calculated logP, and the best two were obtained in correlation of retention constants with MlogP and ClogP. The examination of RM0 and S influence on pharmacokinetics indicated parabolic dependence of the absorption constant (Ka) and plasma protein binding predictor (PPB) from the observed constants while the volume of distribution (Vd) and the ability to cross the brain blood barrier (logBBB) had linear association with the retention parameters. The toxicity of the analysed compounds evaluated in silico as LD50 on rodents was lower in comparison with the drugs with succinimide structure that are on the market and had parabolic correlation with the RM0 and S values. The experiments indicated that none of the compounds examined had cytotoxic activity toward the healthy lung fibroblast cells. The results of the in vitro assay shown that none of the investigated compounds demonstrated antiproliferative activity toward fetal lung cells. The most potent antiproliferative agents were compounds 6 and 7 toward MCF-7 cell line, and compound 11 toward A549 cell line. Molecular docking shown lower energy for binding to ERA in comparison to ERB.</p>
149

Synthesis and Characterization of Biologically Active Imidazolium Salts

Hobbs, Mahala S. 28 July 2023 (has links)
No description available.
150

Synthesis of Bioinspired Dioxygen Reduction Catalysts Involving Mono and Polynuclear Late Transition Metal Complexes and Spectroscopic Trapping of Reactive Intermediates

Chandra, Anirban 24 March 2021 (has links)
Die selektive Funktionalisierung nicht aktivierter C−H-Bindungen und die Disauerstoffreduktionsreaktion (ORR) sind extrem wichtig bei der Beschäftigung mit verschiedenen technologischen Problemstellungen wie der Energiekrise, der Synthese kommerziell relevanter organischer Verbindungen usw. Die Nutzung molekularen Sauerstoffs als reichlich vorhandenes und umweltverträgliches Oxidationsmittel ist von großem Interesse in der Entwicklung bioinspirierter synthetischer Oxidationskatalysatoren. Die katalytische Vier-Elektronen-Reduktion von Disauerstoff zu Wasser erlangte auch immer größere Aufmerksamkeit wegen ihrer Bedeutung in der Brennstoffzellentechnologie. Natürlich vorkommende Metalloenzyme aktivieren Disauerstoff durch die Nutzung günstiger Übergangsmetalle (z.B. Eisen, Nickel, Mangan und Kupfer) und weisen diverse oxidative Reaktivitäten auf. Des Weiteren werden solche Reaktionen unter Umgebungsbedingungen mit hoher Effizienz und Stereoselektivität durchgeführt. Deshalb kann die Isolierung und Charakterisierung hochvalenter Metall-Disauerstoff-Intermediate (wie Metall-Superoxo-, Metall-Peroxo-, Metall-Hydroperoxo- und Metall-Oxo-Verbindungen) eine Menge nützlicher Informationen über die Reaktionsmechanismen liefern und daher hilfreich für die zukünftige Entwicklung effizienterer Katalysatoren sein. Diese Arbeit hat die Chemie verschiedener Metall-Disauerstoff-Intermediate von end-on-1,2-Peroxo-dicobalt(III)-Spezies bis zu Superoxo-nickel(II)-Kernen erforscht. Detaillierte spektroskopische Untersuchungen sowie Reaktivitätsstudien der Intermediate wurden durchgeführt, um den Zusammenhang zwischen ihrer elektronischen Struktur und ihren Reaktivitätsmustern aufzuklären. In meiner Arbeit untersuchte ich den Effekt der ‚Struktur-Aktivität-Beziehung‘ verschiedener Metall-Disauerstoff-Intermediate gegenüber exogener Substrate. Diese Arbeit zeigte auch den Einfluss des Designs geeigneter Liganden auf das Verhalten eines gegebenen reaktiven Metall-Disauerstoff-Systems. / Selective functionalization of unactivated C−H bonds and dioxygen reduction reaction (ORR) are extremely important in the context of addressing various technological issues such as energy-crisis, synthesis of commercially important organic compounds, etc. The utilization of molecular oxygen as an abundant and environmentally benign oxidant is of great interest in the design of bioinspired synthetic oxidation catalysts. The catalytic four-electron reduction of dioxygen to water has also merited increasing attention because of its relevance to fuel cell technology. Naturally occurring metalloenzymes activate dioxygen by employing cheap transition metals (e.g. iron, nickel, manganese, and copper) and exhibit diverse oxidative reactivities. Moreover, such reactions are carried out under ambient conditions with high efficiency and stereospecificity. Therefore, the isolation and characterization of the high-valent metal-dioxygen intermediates (such as metal-superoxo, -peroxo, -hydroperoxo, and -oxo can provide a lot of useful information about the reaction mechanisms and is therefore helpful for the future design of more efficient catalysts. This thesis has explored the chemistry of different metal-dioxygen intermediates ranging from bridging end-on μ-1,2-peroxo-dicobalt(III) species to nickel(II)-superoxo cores. Detailed spectroscopic and reactivity studies of the intermediates have been performed to reveal the correlations between their electronic structures and reactivity patterns. In my present thesis, I investigated the effect of the ‘structure-activity relationship’ of different metal-dioxygen intermediates towards exogenous substrates. This thesis also demonstrated the impact of suitable ligand design on the behaviour of a given metal-dioxygen reactive system.

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