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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.
31

Triterpene Carboxylic Acids as Cortisol Lowering Agents and Synthesis of Hexadeuterated Beta-Ionone

Mogg, Trevor 13 September 2012 (has links)
In part one, betulinic acid (1) was isolated from the American Sycamore (Platanus occidentalis) in 1.6% yield, while ursolic acid (3) was isolated from Fuji and McIntosh apple peels in 1.0% and 0.8% crude yields, respectively. Oleanolic (4) and dehydrocanophyllic (6) acids were previously available, along with several analogs. Additional analogs of 1, 3 and 4 were prepared, including 9 new compounds, for a total of 51 compounds. Compounds were initially screened for cortisol lowering properties in vitro using a fish head kidney cell assay. Platanic acid (43) was selected for in vivo study in rats, along with 1 and a blend of Platanus occidentalis and Souroubea sympetela. No significant cortisol lowering was observed in vivo. In part two, β-ionone-d6 (75) was synthesized in 6.5% yield from ethyl 2-oxo-cyclohexane carboxylate (77). Total deuterium incorporation was 99.85%, with 0.03% d0 analog. 75 was converted to retinoic acid-d6 (93) in 2.2% yield.
32

Contribuição ao conhecimento químico e biológico de espécies da flora paraibana: Xylopia langsdorffiana e Maytenus distichophylla

Esmeraldo, Paula Ferreira dos Santos 23 February 2015 (has links)
Submitted by Cristhiane Guerra (cristhiane.guerra@gmail.com) on 2017-02-03T16:05:21Z No. of bitstreams: 1 arquivototal.pdf: 6455028 bytes, checksum: ad59284d305f31e21541e47aaeb18f12 (MD5) / Made available in DSpace on 2017-02-03T16:05:21Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 6455028 bytes, checksum: ad59284d305f31e21541e47aaeb18f12 (MD5) Previous issue date: 2015-02-23 / Phytochemical studies with Xylopia langsdorffiana (Annonaceae), have described isolation of trachylobane, atisane, kaurane, and labdane diterpenes, from the leaves, fruits, stems and roots of the species. Maytenus distichophylla (Celastraceae), popularly known as espinheira santa – (sacred thorn bush), is used in folk medicine to treat stomach ulcers, and data from the literature report the isolation of triterpenoids friedelane, and pyrimidine sesquiterpene alkaloids. Computer aided drug design brings optimizing techniques that facilitate the discovery of new drugs, offering features that allow the connection of compounds to known proteins in three dimensions, and the resulting models are able to predict reliable experimental values for biologically active molecules, making the search for biologically active compounds more efficient. Our work associated experimental tests and computational investigations based on plants selected from the Paraiban flora: X. langsdorffiana, M. distichophylla, and other Maytenus species. We report the experimental tests performed with roots and stems of Maytenus distichophylla that enabled extraction and structural determination of flavonoids, steroids, and friedelane and lupane triterpenoids. Parallel studies were developed using computational docking, PLS, and hydrophobicity, with 15 triterpenoids isolated from Maytenus species (including M. distichophylla), and 17 diterpenes isolated from X. langsdorffiana. Further, we determined chemical compositions (by GC-MS and NMR), and modulation activity against multi-resistant bacteria. Essential oils of three X. langsdorffiana specimens were analyzed by Principal Component Analysis (PCA). Three compounds were isolated from stems of M. distichophylla by chromatographic techniques: 3-oxo-12α-hydroxyfriedelane, 30- hydroxyfriedelan-3one and 29-hydroxyfriedelan-3-one. Another four compounds were isolated from the roots: β-sitosterol, 11α-hydroxyglochidone, rigidenol and 4’-Omethylepigallocatechin, this being the first report in the species of the latter three. In the docking study, the diterpenes ent-atisan-7α-acetoxy-16α-ol, labdorfianic C acid e labdorfianic B acid had the lowest formation energy values when respectively complexed with cruzaine, CYP2C9, and COX. The triterpenoids with the lowest formation energy values when complexed with these enzymes were, 3β-hydroxy-9,12-en-ursane (cruzaine), 3,4-secofriedelan- 3-oic acid (CYP2C9) and 3-oxo-12α-hydroxyfriedelane (COX). In predicting antitumor activity, as calculated from the constructed PLS model, the diterpene labdorfianic C acid, and triterpene 3β-hydroxyfriedelane, showed the best predicted values. The majority compounds identified in the essential oils were: ent-atisan-16α-ol, germacrene D, limonene and β-pinene. The monoterpenes, β-pinene and limonene, were identified in all analyzed essential oils in different percentages. Through analysis of the essential oil of the X. langsdorffiana stem (specimen A), NMR (¹H and ¹³C) were able to identify ent-atisan-16α-ol, the first time reported for this species. Some essential oils from specimen A when modulated with oxacillin against S. aureus, decreased concentration of the antibiotic by 99%. Principal component analysis (PCA) performed with the essential oil of three X. langsdorffiana specimens allowed identifying a similarity between the chemical species A and B, and a difference in C compared to A and/or B. This result may be related to the age or size of the specimens, since they share the same geographic coordinates. The models obtained in the CADD studies of were satisfactory and generated predictive results. / Estudos fitoquímico com Xylopia langsdorffiana (Annonaceae), descrevem o isolamento de diterpenos do tipo traquilobano, atisano, caurano e labdano, das folhas, frutos, caule e raízes da espécie. Maytenus distichophylla (Celastraceae), conhecida popularmente como espinheira santa, é utilizada na medicina popular para o tratamento de ulceras estomacais, e dados da literatura relatam o isolamento de triterpenos do tipo friedelano e alcaloides sesquiterpênicos pirimidínicos. O planejamento de fármacos auxiliado por computador, vem otimizando técnicas que facilitam na descoberta de novos fármacos, oferecendo recursos que permitem o acoplamento de compostos à proteínas tridimensionalmente conhecidas e originando modelos capazes de predizer valores experimentais confiáveis para moléculas biologicamente ativas, tornando a busca por compostos biologicamente ativos mais eficiente. Este trabalho associou ensaios experimentais e investigações computacionais baseadas nas plantas extraídas da flora Paraibana: X. langsdorffiana, M. distichophylla, e outras espécies do gênero Maytenus. Reportaremos os testes experimentais realizados com raízes e caule de Maytenus distichophylla que possibilitaram a extração e determinação estrutural de flavonoide, esteroide e, triterpenos do tipo friedelano e lupano. Paralelamente realizamos estudos computacionais de docking, PLS e hidrofobicidade, com 15 triterpenos isolados de espécies do gênero Maytenus (incluindo M. distichophylla) e, 17 diterpenos isolados de X. langsdorffiana. Além disso, determinamos a composição química (por CG-EM e RMN), e atividade moduladora frente a bactérias multirresistentes. Os óleos essenciais das 3 espécimes de X. langsdorffiana foram analisadas pela Análise de Componente Principal (PCA). Três compostos foram isolados do caule de M. distichophylla por técnicas cromatográficas: 3-oxo-12α-hidroxifriedelano, 30-hidroxifriedelan- 3ona e 29-hidroxifriedelan-3-ona. Outros quatro compostos foram isolados das raízes: β- sitosterol, 11α-hidroxigloquidona, rigidenol e 4’-O-metilepigalocatequina, sendo os três últimos relatados pela primeira vez na espécie. No estudo de docking, os diterpenos ent-atisan- 7α-acetoxi-16α-ol, ácido labdorfiânico C e ácido labdorfiânico B apresentaram os menores valores de energia de formação quando complexados com a cruzaína, CYP2C9 e COX, respectivamente. Os triterpenos que apresentaram os menores valores de energia de formação complexados com essas enzimas foram, 3β-hidroxi-9,12-en-ursano (cruzaína), ácido 3,4-secofriedelan- 3-óico (CYP2C9) e 3-oxo-12α-hidroxifriedelano (COX). Na predição da atividade antitumoral, calculada a partir do modelo PLS construído, o diterpeno ácido labdorfiânico C, e o triterpeno 3β-hidroxifriedelano, apresentaram os melhores valores preditos. Os compostos majoritários identificados nos óleos essenciais foram: ent-atisan-16α-ol, germacreno D, limoneno e β-pineno. Os monoterpenos, β-pineno e limoneno, foram identificados em todos os óleos essenciais analisados, com diferentes porcentagens. Através da análise do óleo essencial do caule (espécime A) de X. Langsdorffiana, por RMN (¹H e ¹³C) foi possível identificar o entatisan- 16α-ol, relatado pela primeira vez na espécie. Alguns óleos essenciais do espécime A, quando modulados com oxacilina frente a S. aureus, diminuíram a concentração do antibiótico em 99%. A análise de componente principal (PCA) realizada com o óleo essencial de três espécimes de X. langsdorffiana, permitiu identificar uma similaridade química entre os espécimes A e B, e uma diferença em C, quando comparados com A e/ou B. Este resultado pode estar relacionado a idade ou porte dos espécimes, já que os mesmos se encontram na mesma coordenada geográfica. Os modelos obtidos nos estudos de CADD foram satisfatórios e geraram resultados preditivos.
33

Estudo quÃmico de Cestrum laevigatum Schlecht (Solanaceae) / Chemical study of Cestrum laevigatum Schlecht (Solanaceae)

Roberta Ãrika de Souza Silva 27 February 2009 (has links)
FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / O presente trabalho relata o estudo quÃmico do caule de Cestrum laevigatum Schlecht (Solanaceae), coletado no municÃpio de Pacoti-CE. A partir da investigaÃÃo do extrato etanÃlico utilizando tÃcnicas clÃssicas de cromatografia de adsorÃÃo (gel de sÃlica e sÃlica flash) e exclusÃo (Sephadex LH-20) foi possÃvel o isolamento de esterÃides e um triterpeno. Os esterÃides de esqueleto espirostano foram caracterizados como uma mistura de sapogeninas 25(S)-5-espirostano-2,3-diol e 25(R)-5-espirostano-2,3-diol (gitogenina) (CL-1), a mistura de epÃmeros (25R)-5-espirostano-2,3-diol-3-O--D-galactopiranosÃdeo e (25S)-5-espirostano-2,3-diol-3-O--D-galactopiranosÃdeo (CL-2), e a mistura epimÃrica da saponina de carÃter inÃdito na literatura (25R,S)-5-espirostan-2,3-diol-3-O--D-galactopiranosil(1→4)- -D-galactopiranosil(1→4)--D-glicopiranosil (CL-3). AlÃm destes compostos, foram isolados ainda a mistura dos esterÃides -sitosterol e estigmasterol (CL-5) e seus derivados glicosilados (CL-6), alÃm do triterpeno pentacÃclico de esqueleto do tipo lupano β-lup-20(29)-en-3-ol (lupeol) (CL-4). A caracterizaÃÃo estrutural dos compostos isolados foi possÃvel atravÃs do uso de tÃcnicas espectroscÃpicas, principalmente RMN, incluindo seqÃÃncias de pulso uni e bidimensionais, e comparaÃÃo com dados relatados na literatura. Das saponinas investigadas quanto ao potencial antimicrobiano, apenas CL-3 mostrou-se ativa contra Bacillos subtilis, Pseudomonas aeruginosa e Enterobacter aerogenes. A atividade leishmanicida foi realizada com CL-1, CL-2 e CL-3, porÃm, apenas CL-3 mostrou-se ativa contra Leishmania amazonensis. Em relaÃÃo à atividade antifÃngica, CL-1 mostrou-se ativa apenas contra Microsporum canis. CL-2 apresentou excelentes resultados contra Candida albicans, Trichophyton rubrum e Trichophyton mentagrophytes, e uma atividade relativamente boa contra Microsporum canis. Jà CL-3 aparece revelou uma excelente atividade antifÃngica contra todas as cepas testadas. Os resultados promissores obtidos atà o momento a partir do extrato etanÃlico do caule de C. laevigatum confirmam o grande potencial quÃmico/farmacolÃgico das espÃcies deste gÃnero, e justificam a importÃncia do trabalho realizado / This work reports the chemical study of the stem of Cestrum laevigatum Schlecht (Solanaceae), collected at the Pacoti-CE. The investigation of the ethanol extract using conventional techniques of adsorption chromatography (silica gel and silica flash) and exclusion (Sephadex LH-20) was possible the isolation of steroids and triterpene. The spirostan steroids have been characterized as the mixture at the sapogenins 25(S)-5-espirostan-2,3-diol and 25(R)-5-espirostan-2,3-diol (gitogenin) (CL-1), a mixture of epimers (25R)-5-espirostan-2,3-diol-3-O--Dgalactopyranoside and (25S)-5-espirostan-2,3-diol-3-O--D-galactoyiranoside (CL-2), and the mixture of new epimer (25R,S)-5-espirostan-2,3-diol-3-O--Dgalactopyranosil(1→4)--D-galactopyranosil(1→4)--D-glicopyranosil (CL-3). Besides these compounds, were also isolated the mixture of steroids β-sitosterol and stigmasterol (CL-5) and its glycosides (CL-6), and the pentacyclic triterpene β-lup-20(29)-en-3-ol (lupeol) (CL-4). The structural characterization of the isolated compounds was possible through the use of spectroscopic techniques, mainly NMR, including sequences of uni and bidimensional pulse, and comparison with literature data. CL-3 was shown to be active against Bacille subtilis, Pseudomonas aeruginosa and Enterobacter aerogenes. The leishmanicide activity was performed with CL-1, CL-2 and CL-3, however, only CL-3 was shown to be active against Leishmania amazonensis. For the antifungical activity, CL-1 was shown to be active only against Microsporum canis. CL-2 showed excellent results against Candida albicans, Trichophyton rubrum and Trichophyton mentagrophytes, and a relatively good activity against Microsporum canis. CL-3 appears with excellent activity antifungical against all strains tested. The promising results obtained so far from the ethanol extract of the stem of C. laevigatum confirm the great potential chemical / pharmacological species of this genus, and justify the importance of work
34

Efeito do Triterpeno 3β, 6β, 16β , trihidroxilup-20(29)-eno nas convul-sões induzidas por pentilenotretazol: papel da Na+, K+ ATPase / Triterpene 3β , 6β, 16β trihidroxilup-20(29)-ene protects against excitability and oxidative damage induced by pentylenetetrazol: The role of Na+,K+-ATPase activity

Pace, Iuri Domingues Della 30 September 2013 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Epilepsy is a syndrome characterized by spontaneous recurrent seizures, result of paroxys-mal discharges , excessive or synchronous a neural population . Despite the good prognosis, the high number of patients with epilepsy who have seizures refractory to medication, reflects the lack of a bet-ter understanding of excitotoxic disorders characteristic of this disease. Thus, it becomes important to understand the mechanisms for induction and maintenance of seizures as well, the search for new antiepileptic compounds that may prevent the development of this pathology. As nociception and epi-lepsy have mechanisms in common and several anticonvulsant drugs are used in treatment of pain , we investigated the effect of triterpene 3β , 6β , 16β Trihidroxilup -20 ( 29) -ene (TTHL), a compound with antinociceptive properties in convulsions induced by pentylenetetrazol (PTZ). The TTHL admin-istration ( 30 mg / kg , po) increased the latency to the first myoclonic seizures and tonic- clonic sei-zure and decreased the duration of generalized seizures induced by PTZ . In addition , the administra-tion of TTHL reduced lipid peroxidation and protein carbonylation , as well as protected from inhibition of glutamate uptake and activity of the Na+, K+-ATPase (α1and α2/α3 subunits ) caused by PTZ . Alt-hough the TTHL showed no antioxidant activity per se and not alter the binding of [ 3H ] flunitrazepam to the site of the GABAA receptor bezodiazepínico , this protected compound of convulsions and inhi-bition of Na+, K+-ATPase activity induced by ouabain . These results suggest that the anticonvulsant action is due TTHL s maintenance of Na+, K+-ATPase . In fact , the experiments performed in the cer-ebral cortex in vitro showed that PTZ ( 10 mM ) reduced the activity of Na+, K+-ATPase and that prein-cubation with TTHL ( 10 mM ) protected from this inhibition.Thus , these data indicate that the protec-tion exerted by TTHL this seizure model is not related to antioxidant activity or GABAergic activity . However, these results demonstrate that effective protection of Na+, K+-ATPase activity induced by this compound protects against oxidative and excitotoxic damage induced by PTZ . / A epilepsia é uma síndrome caracterizada por crises espontâneas e recorrentes, resultado de descargas paroxísticas, excessivas e sincrônicas de uma população neural. Apesar do bom prognós-tico, o elevado número de pacientes com epilepsia, que apresentam convulsões refratárias aos medi-camentos, reflete a falta de um melhor entendimento dos distúrbios excitotóxicos característico desta doença. Desta forma, torna-se importante o entendimento dos mecanismos de indução e manuten-ção das convulsões, bem como, a busca por novos compostos anticonvulsivantes que possam evitar o desenvolvimento desta patologia. Como a nocicepção e a epilepsia possuem mecanismos em co-mum, e vários anticonvulsivantes são usados no tratamento da dor, foi investigado o efeito do Triter-peno 3β,6β,16β Trihidroxilup-20(29)-eno (TTHL), um composto com propriedades antinociceptivas, nas convulsões induzidas pelo pentilenotetrazol (PTZ). A administração do TTHL (30 mg/kg; p.o) au-mentou a latência para a primeira convulsão mioclônica e tônico-clônica e reduziu a duração das convulsões generalizadas induzidas pelo PTZ. Além disso, a administração do TTHL reduziu a pero-xidação lipídica e a carbonilação de proteínas, assim como, protegeu da inibição da captação de glu-tamato e da atividade da Na+,K+-ATPase (subunidades α1 e α2/α3) causadas pelo PTZ. Embora, o TTHL não mostrou uma atividade antioxidante per se e não alterou a ligação do [3H]flunitrazepam ao sítio para bezodiazepínico do receptor GABAA, este composto protegeu das convulsões e da inibição da atividade da Na+, K+- ATPase induzidos pela ouabaina. Estes resultados sugerem que a ação an-ticonvulsivante do TTHL é devido s manutenção da atividade da Na+,K+-ATPase. De fato, os experi-mentos realizados no córtex cerebral in vitro mostraram que o PTZ (10 mM) reduziu a atividade da Na+,K+-ATPase e que a incubação prévia com TTHL (10 μM) protegeu desta inibição. Dessa forma, estes dados indicam que a proteção exercida pela TTHL neste modelo de convulsão não está relaci-onado com atividade antioxidante ou a atividade GABAérgica. No entanto, estes resultados demons-traram que a proteção eficaz da atividade da Na+,K+-ATPase , induzida por este composto, protege contra os danos excitotóxic e oxidativos induzidos pelo PTZ.
35

Valorisation des coproduits de l'holothurie Cucumaria frondosa par l'étude d'extraits bioactifs et approche écotoxicologique des métabolites secondaires relargués en situation de stress / Upgrading of byproducts from the holothurian Cucumaria frondosa by the study of bioactive extracts and ecotoxicological approach of the secondary metabolites released under stress conditions

Tripoteau, Ludovic 12 May 2015 (has links)
La transformation des produits marins génère d’importantes quantités de rejets. La majorité est transformée pour des applications de masse avec une faible valeur ajoutée. Au Nouveau Brunswick, 85 000 tonnes de produits marins sont transformés annuellement et la moitié est peu ou pas valorisée, c’est le cas de l’holothurie Cucumaria frondosa. Face aux différentes pressions de leur environnement, et notamment la prédation, ces invertébrés marins ont évolué en développant des métabolites d’une large chimiodiversité, ce qui en fait d’excellents candidats pour le développement de substances naturelles bioactives. L’objectif de cette étude a tout d’abord été de chercher à valoriser les coproduits majeurs de Cucumaria frondosa en constituant une large librairie d’extraits et en évaluant, par fractionnement bioguidé, les activités antiherpétiques in vitro des fractions obtenues par différents procédés d’extraction (extractions par solvants et hydrolyses enzymatiques). Nous avons pu mettre en évidence la présence de fractions anti-VHS-1 (Virus Herpes Simplex de type 1). L’hydrolyse enzymatique s’est avérée être une technique efficace pour la génération de substances actives. Le bulbe aquapharyngé peu considéré d’un point de vue industriel représente un réel potentiel pour l’extraction de composés anti-VHS-1, et notamment lorsque celui-ci est hydrolysé par la papaïne en conditions contrôlées. L’activité antiherpétique la plus efficace a été reliée à la présence de molécules à haut poids moléculaires. Dans un second temps, nous avons cherché à comprendre et à mettre en évidence les mécanismes de défense de l’holothurie par l’étude de ces métabolites secondaires relargués en situation de stress. Les métabolites ont été évalués sur différents modèles écotoxicologiques et les molécules actives ont été caractérisées par fractionnement bioguidé par l’utilisation de modèle d’évaluation de cytotoxicité, en parallèle à différents procédés analytiques. L’étude a confirmé l’existence et la production de composés toxiques relargués en situation de stress. Ces métabolites secondaires ont montré une forte toxicité sur différents modèles écotoxicologiques chronique et aiguë. Le fractionnement bioguidé par couplage analytique nous a conduit à l’identification de plusieurs composés du type glycoside triterpénique et notamment le Frondoside A retrouvé dans la fraction responsable de la cytotoxicité. L’étude a permis d’optimiser l’extraction de ce composé d’un intérêt biologique prometteur sans pour autant entraîner la mort de l’animal. / The transformation of marine products generates huge quantities of rejects. The majority of these rejects is used for an upgrading of products with low added value. In New Brunswick, 85 000 tons of marine products are transformed annually, the half is little or not upgraded, that is the case of the holothurian Cucumaria frondosa. Confronted with environmental pressures, and especially predation, the marine invertebrates have evolved and developed various metabolites of different chemical classes. Thus, these metabolites represent ideal candidates for the development of new natural bioactive substances. The objectives of this study was first based on the upgrading of the major byproducts from Cucumaria frondosa by creating a wide library of extracts obtained by different type of extractions (solvent extractions and enzymatic hydrolysis) and then, by bioguided fractionation, evaluating the in vitro anti-HSV-1 (Herpes Simplex Virus, type 1) activities of the fractions. We showed the presence of potent antiherpetic fractions without cytotoxicity on mammalian cells. The enzymatic hydrolysis has been demonstrated to be efficient for the generation of high molecular weight active substances regarding HSV-1. The aquapharyngeal bulb, considered to be less used industrially, represents a real potential for the extraction of anti-HSV-1 compounds, and especially when hydrolyzed by papain under controlled conditions. Secondly, we have searched to understand the mechanism of defense of the holothurian under stress conditions. The secondary metabolites involved were evaluated on different ecotoxicological models. This work has confirmed the existence and the production of toxic compounds released under stress conditions. These secondary metabolites have shown a strong toxicity on acute and chronic ecotoxicological models. The bioguided fractionation assisted by analytical evaluation led to the identification of several triterpene glycosides, and especially the Frondoside A into the cytotoxic fraction. This study has permitted the optimization of the upgrading of the byproducts from Cucumaria frondosa by the extraction of antiherpetic molecules without cytotoxicity and the identification and the characterization of the defense
36

Triterpene Carboxylic Acids as Cortisol Lowering Agents and Synthesis of Hexadeuterated Beta-Ionone

Mogg, Trevor January 2012 (has links)
In part one, betulinic acid (1) was isolated from the American Sycamore (Platanus occidentalis) in 1.6% yield, while ursolic acid (3) was isolated from Fuji and McIntosh apple peels in 1.0% and 0.8% crude yields, respectively. Oleanolic (4) and dehydrocanophyllic (6) acids were previously available, along with several analogs. Additional analogs of 1, 3 and 4 were prepared, including 9 new compounds, for a total of 51 compounds. Compounds were initially screened for cortisol lowering properties in vitro using a fish head kidney cell assay. Platanic acid (43) was selected for in vivo study in rats, along with 1 and a blend of Platanus occidentalis and Souroubea sympetela. No significant cortisol lowering was observed in vivo. In part two, β-ionone-d6 (75) was synthesized in 6.5% yield from ethyl 2-oxo-cyclohexane carboxylate (77). Total deuterium incorporation was 99.85%, with 0.03% d0 analog. 75 was converted to retinoic acid-d6 (93) in 2.2% yield.
37

Extraction, purification, and structurala nalysis of glycosylated natural products, mimetics of native antigens involved in an immune response / Extraction, purification et analyse structurale de produits naturels glycosylés, mimétiques d'antigènes natifs impliqués dans la réponse immunitaire

Champy-Tixier, Anne-Sophie 23 March 2018 (has links)
Cette these en cotutelle entre le Laboratoire Peptlab de l’Université de Florence en Italie et le Laboratoire de Pharmacognosie de l’Université de Bourgogne Franche-Comté en France, porte sur l’extraction, la purification et l’élucidation structurale de saponines d’origine végétale en tant que mimétiques d’antigènes impliqués dans une réponse immunitaire. L’étude phytochimique de cinq espèces végétales appartenant à trois familles différentes, Fabaceae : Wisteria frustecens, Wisteria floribunda “macrobotrys”, Wisteria floribunda “rosea”, Caprifoliaceae : Weigela florida “rumba” et Polygalaceae : Polygala acicularis, a conduit à l’isolement de seize glycosides triterpéniques naturels parmi lesquelles six sont de structure nouvelle, une a été isolée sous sa forme native pour la première fois, et neuf déjà répertoriées dans la littérature. Les composés ont été isolés grâce à l’utilisation de différentes méthodes chromatographiques. Leurs structures ont été élucidées en utilisant principalement la RMN 2D et la spectrométrie de masse. Parmis ces seize molécules, six ont été sélectionnées pour être testées en tant que mimétiques d’antigènes impliqués dans une réponse immunitaire. De plus, un flavonoïde glycosylé extrait de Sophora japonica et un acide triterpénique commercial, l’acide ursolique, ont eux aussi été choisis comme mimétiques d’antigènes. Des tests immunochimiques (ELISA) ont été réalisés afin d’évaluer leur potentiel en tant que mimétiques d’antigènes dans le sang de patients atteints de sclérose en plaque ou du syndrome de Rett. Le taux IgM dans le sérum des patients atteints de sclérose en plaque ou du syndrome de Rett a été mesuré et comparé à celui de donneurs sains. Concernant la sclérose en plaque, les résultats sont peu significatifs concernant le potentiel des saponines en tant que mimétiques d’antigènes. Mais dans le cas du syndrome de Rett des résultats intéressants et surprenants ont été obtenus. En effet, l’hypothèse de départ était l’implication de la partie glycosylée dans la reconnaissance d’autoanticorps. Pour le syndrome de Rett, l’acide ursolique, qui est un aglycone, démontre une grande efficacité dans la reconnaissance d’IgM. Par contre, un triterpène glycosylé démontre lui aussi une efficacité semblable. Les résultats obtenus sont donc à analyser afin d’établir des relations structure/activité fiables. / This PhD in co-direction between the Peptlab Laboratory of the University of Firenze (Italy) and the Laboratory of Pharmacognosy of the University of Bourgogne Franche-Comté (France), deals with extraction, purification and structural elucidation of saponins from plants as mimetic antigens involved in an immune response. The phytochemical study of five species from three different families, Wisteria frustecens, Wisteria floribunda “macrobotrys” and Wisteria floribunda “rosea” from Fabaceae, Weigela florida “rumba” from Caprifoliaceae, and Polygala acicularis from Polygalaceae, allowed us to isolate sixteen natural glycosides: six with new structures, one analyzed for the first time in its native form, and nine which have been already described in the literature. These compounds were isolated using various chromatographic methods, and their structures were elucidated using mainly 2D NMR and mass spectrometry. From the isolated glycosides, six were selected and tested as mimetics of native antigens involved in the immune response. Moreover, one flavonoid glycoside extracted from Sophora japonica, and one commercial triterpenic acid, ursolic acid, were also chosen as mimetics of native antigens. Immunoenzymatic assays (ELISA) were performed for each compound to evaluate their potential as mimetics of native antigens of multiple sclerosis and Rett syndrome. The IgM levels in sera of patients affected by multiple sclerosis and Rett syndrome were measured and compared to normal blood donors. Concerning multiple sclerosis, no significant results were obtained for saponins, but in the case of Rett syndrome, interesting and surprising results were obtained. Indeed, the first hypothesis was that the glycosyl part of the molecule could be relevant for antibody recognition. In the case of Rett syndrome ursolic acid, an aglycone without any glycosidic part, demonstrated a good efficiency in IgM recognition. On the other hand, one triterpenic glycoside showed similar results. These results were discussed to define possible structure/activity relationships.
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Die Chemilumineszenz - Ihre Anwendung in der Konservierungsforschung bei der Untersuchung der Stabilität eines Triterpen-Naturharzes

Buder, Andreas 15 March 2024 (has links)
In der Konservierungsforschung werden unterschiedlichste Materialien analysiert und auf ihre Stabilität hin geprüft, um gezielte Konservierungs- oder Restaurierungsmassnahmen durchzuführen und deren Nachhaltigkeit besser einschätzen zu können. Die Chemilumineszenz - im Folgenden kurz CL - ist ein Phänomen, bei dem ein Elektron aus einem energetisch höher gelegenen Orbital in einen tiefer liegenden Zustand relaxiert und dabei seine Energie in Form von Photonen abgibt. Der angeregte Zustand wird durch eine chemische Reaktion verursacht. Dieser Vorgang ist sehr spezifisch und tritt u.a. bei Oxidationsreaktionen auf. Durch Rekombination zweier Peroxide wird z.B. eine angeregte Carbonylverbindung erzeugt, die ihre Energie als Licht emittiert. Dieser Zusammenhang zwischen der Oxidation organischer Substanzen und die Emission von Photonen bedingt die hier zentral gestellte Frage, ob die Chemilumineszenz als Methode zur Charakterisierung von Materialien, die in der Konservierungsforschung relevant sind, eingesetzt werden kann. Innerhalb einer Forschungskooperation zwischen Departementen der Berner Fachhochschule BFH konnte ein Chemilumineszenz-Messgerät konstruiert, modifiziert und für diese Arbeit eingesetzt werden. In der Arbeit wurde ein standardisiertes Messverfahren an verschiedenen Substanzen, wie z.B. Adamantylidenadamantan-1.2-dioxetan geprüft und die verschiedenen Einflüsse auf das Chemilumineszenz-Signal untersucht. Dabei konnten für das Messprinzip wichtige Daten, wie z.B. Präzision, Nachweis- und Bestimmungsgrenze erhoben werden. Anhand der Stabilität von Dammar, einem Triterpen-Naturharz, konnte das Verfahren innerhalb der Arbeit, an einem komplexen Beispiel aus der Konservierungsforschung experimentell erprobt werden. Dabei wurden publizierte Resultate zum Oxidationsverhalten von Dammarharz teilweise verifiziert. Durch das spezifische Signal konnten die thermisch initiierten Reaktionen bei inerten und oxidativen Gas-Atmosphären dokumentiert werden. Die Ergebnisse wurden mit etablierten Methoden, wie z.B. DSC, TGA und ESR- Spektroskopie verglichen und Konsistenzen zu den Signalen erfasst. Der in der Literatur diskutierte Einfluss von Stabilisatoren auf Dammarharz-Filme wurde an ungealterten und künstlich gealterten Proben mit der Chemilumineszenz untersucht. Dabei konnten ebenfalls in der Literatur empfohlene Formulierungen und Wirkungen bestimmter synergetischer Mischungen nachgewiesen und bestätigt werden. Aus den ermittelten Daten der CL-Messungen liessen sich in einem Ausblick kinetische Berechnungen zu Aktivierungsparametern erstellen. Die ermittelten Parameter wurden zur Prognose von Reaktionsverläufen bei unterschiedlich simulierten Temperaturprofilen genutzt und machten eine Vorhersage zur Lebensdauer der Materialien möglich. Neben der hohen Leistungsfähigkeit der Methode zeigte sich v.a. das hohe Potential der ermittelten Messdaten, v.a. in Bezug auf die Anwendung in der Modellfreien Kinetik. Neben diesen Möglichkeiten wurden aber auch die Grenzen der Methode aufgezeigt. Diese sind einerseits durch die Besonderheit des Signals gegeben, welches mechanistisch bis heute noch nicht vollständig aufgeklärt ist, andererseits liegen sie bei der Weiterverarbeitung der Messdaten durch thermokinetische Software. Hier wird deutlich, dass die Qualität der Berechnungen zu Reaktionsverläufen nur so gut ist, wie die zuvor erhobenen Daten und, dass erstellte Prognosen zur Stabilität eines Materials lediglich eine Vorstellung vermitteln können. / During conservation studies different materials are analysed and tested for their solidity in order to be able to carry out precise conservation and restoration measures and to be able to assess their sustainability. Chemiluminescence is a phenomenon in which an electron is relaxed from an energetically higher orbital into a lower situated condition while simultaneously releasing energy in the shape of photons. As a consequence the stimulated state is caused by a chemical reaction. This process is very specific and occurs during an oxidation reaction among other things. Through the recombination of two peroxides for example a stimulated carbonyl compound is generated which emits its energy as light. This connection between the oxidation of organic substances and the emission of photons determines the main question, whether chemiluminescence can be used as a method for characterisation of materials which are relevant to the research of conservation. As a result of a research project between departments of the Bern University of Applied Sciences BFH it was possible to construct a chemiluminescence measuring device and modify it in a way that it could be used for this work. Within this experiment a standardised method of measurement was tested on different substances, for example adamantylidenadamantan-1.2-dioxetan, and the different impacts on the chemiluminescence-signal investigated. Through this process important facts were determined for the concept of measurement, for example precision, proof- and definition perimeters. Based on the solidity of dammar, a triterpene resin, the method could be experimentally verified within the test using a complex example from conservation research. Within that process published results about the oxidation properties of dammar resin were verified. Due to the specific signal, the thermally initiated responses in inert as well as oxidative gas atmospheres could be documented. The results were compared with established methods like DSC, TGA and ESR spectroscopy and the consistencies to the signals logged. The already much discussed influence of stabilisers on dammar resin was tested on nonaged and artificially aged specimens using chemiluminescence. Through these previously suggested formulations, effects of certain synergistic composites were detected and confirmed. Using the data from the chemiluminescence measurements kinetic calculations about activation parameters were compiled. The identified parameters were used for the prognosis of the course of reactions during differently simulated temperature profiles, making a prediction of the materials’ life span possible. Through these results not only the high performance ability of the method became apparent but also the potential of the determined measurement data, mainly in connection with the application within the model-free kinetic. However, alongside these possibilities limitations of the method were revealed. These are partly caused by the characteristics of the signal which has yet to be mechanistically fully clarified. Simultaneously, further processing of the measurement data via thermokinetic software makes clear that the quality of the calculations of the reaction process is only as good as the quality of the initial data. This suggests the prognoses about the stability of the material only conveys a concept of their qualities.
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Complexation de triterpènes pentacycliques par des cyclodextrines : caractérisations physicochimiques et activités biologiques / Complexation of pentacyclic triterpenes by cyclodextrines : physicochemical characterization and biological activities

Fontanay, Stéphane 20 December 2012 (has links)
Le manque de thérapies innovantes en chimiothérapie humaine incite la communauté scientifique à s'intéresser à de nouvelles sources de composés bioactifs. Nous pouvons citer les métabolites secondaires de plantes, auxquels appartiennent les acides hydroxy pentacycliques triterpénoiques (AHPTs) et plus particulièrement les Acides Ursolique (AU), Oléanolique (AO) et Bétulinique (AB). Ces molécules font l'objet de nombreuses études qui tendent à démontrer leurs propriétés : anti-infectieuses, anticancéreuses, antiprolifératives, anti-inflammatoires, hépatoprotectrices. Le principal obstacle à leur utilisation à des fins thérapeutiques, reste l'insolubilité de ces AHPTs dans l'eau. L'objectif de ce travail a donc été d'augmenter leur hydrosolubilité. Dans un premier temps, en accord avec les recommandations et/ou normes existantes, nous avons démontré que le spectre d'activité antibactérienne de l'AU et de l'AO se limitait aux bactéries à Gram positif. Aucun AHPT n'a montré d'activité antifongique. Seul l'AB a montré une activité intéressante sur le Cytomégalovirus humain (hCMV) ; aucune activité antivirale n'ayant été retrouvée sur le Poliovirus. Enfin, l'AB, mais encore plus l'AU ont montré une activité anticancéreuse à l'encontre de cellules modèles de leucémie myéloïde chronique (LMC). Dans un deuxième temps, nous avons procédé à la fabrication et à l'étude de complexes entre les AHPTs et des cyclodextrines. Nous avons retenu la gamma-cyclodextrine (gamma-CD), qui présentait l'avantage de complexer les 3 AHPTs avec une constante de formation « moyenne » à « élevée ». Ces complexes AHPTs :gamma-CD ont été caractérisés en utilisant diverses techniques : chromatographiques, thermiques et spectrométriques. Nous avons conclu à l'obtention de complexes d'inclusion qui ont permis d'augmenter la solubilité des AHPTs. Dans une dernière partie, nous avons évalué les activités biologiques des complexes AHPTs : gamma-CD. Les résultats montrent que les complexes AU : gamma-CD et AO : gamma-CD restent actifs à l'encontre des bactéries à Gram positif (mais avec une efficacité plus faible) ; tandis que le complexe AB : gamma-CD se révèle être actif sur certaines bactéries. Le complexe AB : gamma-CD, et de façon surprenante le complexe AU : gamma-CD présentent une activité antivirale à l'encontre du hCMV. Enfin, la diminution de la cytotoxicité liée à la complexation des AHPTs accroit l'intérêt des molécules d'AU et d'AB sur les cellules de LMC / The lack of innovative therapies in human chemotherapy incites the scientific community to be interested in new sources of bioactive compounds. We can quote the secondary metabolites of plants, to which belong hydroxy pentacyclic triterpene acids (HPTAs) and more particularly Ursolic (UA), Oleanolic (OA) and Betulinic Acids(BA). These molecules are the subjetc of numerous studies which tend to demonstrate their properties: anti-infective, anticancer, antiproliferatives, anti-inflammatory and hepatoprotectrive. The main obstacle to their use in therapeutic purposes stays the insolubility of these AHPTs in the water. Thus the objective of this work was to increase their hydrosolubility. At first, in agreement with the recommendations and/or the existing standards, we demonstrated that the antibacterial spectra of UA and OA are limited to Gram-positive bacteria. No HPTA showed antifungal activity. Only the BA showed an interesting antiviral activity on human Cytomegalovirus (hCMV); no antiviral activity was on Poliovirus. Finally, the BA, but even more UA showed an anticancer activity against cellular model of chronic myeloid leukemia (CML). Secondly, we proceeded to the manufacturing and to the study of complexes between HPTAs and cyclodextrines. We retained gamma-cyclodextrine (gamma-CD), which presented the advantage to complex the 3 AHPTs with a constant of "average" to "raised". These HPTAs:gamma-CD complexes were characterized by using diverse techniques: chromatographic, thermal and spectrometric. We concluded in the obtaining of inclusion complexes which allowed increasing the solubility of the HPTAs. In a last part, we estimated the biological activities of the HPTAs:gamma-CD complexes. The results show that the UA:gamma-CD and OA:gamma-CD complexes remain active against Gram-positive bacteria (but with a weaker efficiency); whereas the BA:gamma-CD complex shows to be active on certain bacteria. The BA:gamma-CD complex, and in a surprising way the UA:gamma-CD complex presents an antiviral activity against the hCMV. Finally, the decrease of the cytotoxicity linked to the complexation of the HPTAs believes the interest of UA and of BA on CML cells
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Isolement et caractérisation de saponosides extraits de deux plantes médicinales : Cyclamen africanum, Zygophyllum cornutum et évalution de leur activité anti-inflammatoire / Isolation and characterization of two saponosides extracts herbs Cyclamen africanum, Zygophyllum cornutum and assessment of their anti-inflammatory activity

Betina-Bencharif, Soumeya 13 October 2014 (has links)
L’apparition de plusieurs maladies, telles que le cancer, le diabète, l'hypertension artérielle et la propagation d'infections de type virus mutagènes peuvent être liées à la qualité et au mode de vie que nous menons aujourd’hui. En effet, plusieurs études sur les facteurs déclenchant ces maladies dites "morbides" à long ou à court terme, sont liées au stress et à la qualité des aliments consommés, qu'ils soient d'origine végétale ou animale. Ces maladies deviennent un phénomène courant, elles touchent différentes races et toutes les catégories de la société. D'après les recherches ethnobotaniques, les substances d’origine naturelle, ont permis à des civilisations de survivre à des maladies mortelles. A titre d'exemple, on retrouve ainsi des références à des périodes de fièvre paludique en Chine et à des symptômes de cette maladie dans le «Huangdi Neijiang» Le Canon de Médecine datant des environs du premier siècle avant notre ère, plus de 2000 ans, qui relate de l'emploi de plantes médicinales, pour soulager les fièvres (Desgrouas et al., 2014).Vers 186 avant J.-C. apparaît, dans certaines régions de Chine, l'utilisation en tisane, du Qing hao su, appelé plus tard artémisinine en Occident et extrait d'une plante médicinale utilisée comme antipyrétique appelée "Qing hao", Artemisia annua ou Armoise annuelle. L'artemisinine bloque une enzyme qui permet au parasite de pomper le calcium et l'empêche ainsi de se développer. Au jour d'aujourd'hui l’Artemisinin-based combination therapy, en français Thérapie combinée à base d'artémisinine et en sigle ACT, est une thérapie et une prévention tertiaire dans les cas de paludisme simple.Dans cette optique notre étude vient s'ajouter à une longue série d'études menées sur les plantes médicinales et les substances naturelles extraites. Elle a pour objectif de révéler de nouvelles biomolécules, de mettre en évidence leurs activités biologiques grâce à des techniques de biotechnologies d'une part. D'autre part ces investigations permettront de valoriser les ressources naturelles qui se distinguent par leur endémicité.Pour se faire, notre choix s'est porté sur deux plantes médicinales endémiques à l'Algérie Cyclamen africanum Boiss. & Reuter et Zygophyllum cornutum Coss. , après une recherche ethnobotanique sur la pharmacopée traditionnelle du Nord de l'Afrique, et qui a révélé l’efficacité de ces plantes dans les problèmes inflammatoires minimes chez les autochtones, nous avons entrepris des investigations pharmaco- biochimiques.Ces dernières nous ont permis d'isoler : cinq composés à partir de l'extrait méthanolique des racines de l'espèce Cyclamen africanum Boiss. & Reuter, deux nouvelles saponines triterpéniques de type Oleanane, Afrocyclamin A et B (1, 2), ainsi que trois saponines triterpénoïdes connus sous le nom de lysikokianoside (3), deglucocyclamin I (4) et de son dérivé d'acide dicrotalique (5); et Sept saponosides connus à partir de l'extrait méthanolique de la plante entière de Zygophyllum cornutum Coss., ces saponosides sont de type ursane, ce type de triterpène est rapporté dans cette espèce pour la première fois et peuvent être considérés comme un marqueur chimio-taxonomique (chemotype) du genre Zygophyllum. Les structures ont été élucidées, sur la base de l'analyse des spectres de l'expérience RMN-1D et RMN- 2D (COSY, TOCSY, NOESY, HMBC et HSQC) et spectrométrie de masse en source FAB mode ion négatif. Des activités biologiques, des fractions saponosidiques Fr.1 et Fr.2, ont été testées sur des lignées de Rats mâles et femelles, de la race Winstar pour évaluer l'activité anti inflammatoire.La fraction saponosidique Fr.1 de Cyclamen africanum à la dose 5 mg, a montré un effet significatif sur l'inflammation causé par la carragénine, en réduisant l'oedème et la réponse immunitaire, qui s'est traduite par la concentration des protéines de la réponse inflammatoire (PRI) à travers leurs action sur les pro-médiateurs de l'inflammation (COX-2, PGE2, TNF -α, iNOS). / The appearance of several diseases, such as cancer, diabetes, high blood pressure and spread of infections mutagenic virus type can be linked to the quality and lifestyle that we lead today. Indeed, several studies on the factors triggering these so-called "morbid" long-or short-term illnesses are related to stress and quality of food consumed, whether of plant and animal origin. These diseases are becoming a common occurrence, they affect different races and all classes of society. According ethnobotanical research, naturally occurring substances, allowed civilizations to survive deadly diseases. For example, we thus find references to periods of malarial fever in China and one of the symptoms of this disease in the "Huangdi Neijiang" The Canon of Medicine dating from around the first century BC, more than 2000 years, which relates to the use of herbal medicines to relieve fevers (Desgrouas et al., 2014).Around 186 BC appears, in some parts of China, the use in herbal tea, Qing hao su, later known as artemisinin in the West and extracted from a medicinal plant used as antipyretic called "Qing hao" Artemisia annua or annual wormwood. Artemisinin blocks an enzyme which enables the parasite to pump calcium and prevents it from developing. As of today the Artemisinin-based combination therapy in French Combination therapy of artemisinin and ACT acronym, is a therapy and tertiary prevention in cases of uncomplicated malaria.From this perspective our study adds to a long series of studies on medicinal plants and natural substances extracted. It aims to reveal new biomolecules, highlighting their biological activities through techniques of biotechnology on the one hand. Moreover, these investigations will develop natural resources that are characterized by endemic.To do this, our choice is focused on two endemic medicinal plants in Algeria Cyclamen africanum Boiss. & Reuter and Zygophyllum cornutum Coss. After an ethnobotanical research on traditional medicine in Northern Africa, which showed the effectiveness of these plants in minimal inflammatory problems among Aboriginal, we undertook biochemical pharmacological investigations.The latter allowed us to isolate, five compounds from the methanol extract of the roots of the species Cyclamen africanum Boiss. Reuter & two new oleanane triterpene saponins type, Afrocyclamin A and B (1, 2) and three triterpenoid saponins known lysikokianoside of (3), deglucocyclamin I (4) and its derivative dicrotalique acid (5) September and known from the methanol extract saponins from the whole plant of Zygophyllum cornutum Coss. these saponins are ursane type, type triterpenes are reported in this species for the first time and can be considered a chemotherapy marker Taxonomic (chemotype) of Zygophyllum kind. The structures were elucidated on the basis of the analysis of NMR spectra of the experience-1D and 2D-NMR (COSY, TOCSY, NOESY, HSQC and HMBC) and mass spectrometry method negative ion FAB source. The biological activities of saponosidiques FR.1 and Fr.2 fractions were tested on lines of male and female rats of the Winstar rats to evaluate the anti-inflammatory activity. The saponosidique fraction FR.1 Cyclamen africanum the 5 mg dose, showed a significant effect on inflammation caused by carrageenan, reducing edema and immune response, which resulted in the concentration of protein the inflammatory response (PRI) through their action on the pro-inflammatory mediators (COX-2, PGE2, TNF -α, iNOS). The fraction of Fr.2 saponosidique Zygophyllum dose 20 mg did not show a significant effect on inflammation in general.

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