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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.
311

Distribution par filtration sur gel de la matière organique dissoute en fonction du poids moléculaire nominal dans trois types d'eau du Saguenay /

Levert, Luc. January 1990 (has links)
Mémoire (M.P.Aquat.)--Université du Québec à Chicoutimi, 1990. / Document électronique également accessible en format PDF. CaQCU
312

HPLC method development for characterisation of the phenolic composition of Cyclopia subternata and C. maculata extracts and chromatographic fingerprint analysis for quality control

Schulze, Alexandra Elizabeth 12 1900 (has links)
Thesis (MScFoodSc)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: The phenolic composition of Cyclopia species is believed to be partially responsible for the numerous health promoting properties associated with their extracts. Current quality control measures do not accommodate variation in phenolic profiles of Cyclopia species. In this study, comprehensive high performance liquid chromatography (HPLC) methods were developed for the improved characterisation of the phenolic composition of aqueous extracts of two Cyclopia species (C. subternata and C. maculata). The methods were developed to be suitable for both routine quantitative analysis on conventional HPLC instrumentation, and the construction of chromatographic fingerprints for further data analysis. The latter entailed similarity analysis and prediction of total antioxidant capacity (TAC). Using a methodical approach, two separate HPLC methods, using diode array detection (DAD), were developed and validated for the analysis of aqueous extracts prepared from unfermented (green) and fermented plant material of C. subternata and C. maculata. Separation was achieved using the same method parameters (column, temperature, mobile phases), except for differing mobile phase gradients. Hyphenation of the developed HPLC methods with mass spectrometry (MS) and tandem MS allowed the confirmation of phenolic compounds previously identified in Cyclopia, and the tentative identification of several additional compounds in Cyclopia species, which are reported here for the first time. These included apigenin-6,8-di- C-glucoside, 3-hydroxyphloretin-30,50-di-C-hexoside, eriodictyol-di-C-glucoside, iriflophenone-di-O,C-hexoside, hydroxymangiferin and hydroxyisomangiferin. Subsequently, a large number of aqueous extracts of randomly selected green C. subternata (n = 64) and C. maculata (n = 50) plant material samples were analysed. Large quantitative variations were observed on intra- and inter-species levels. Cyclopia maculata extracts contained almost six times more mangiferin than extracts from C. subternata. HPLC-DAD analysis produced duplicate fingerprints for each extract which were consequently used for further analysis. The chromatographic fingerprint of a bioactive extract of each species was included in the respective data sets. Similarity analysis was conducted between the fingerprints from the randomly selected extracts and the corresponding active extract. For each species several extracts were determined to have similar “activity” as that of the active extract (n = 15 for C. subternata and n = 45 for C. maculata). Compounds potentially responsible for the activity were tentatively identified with the aid of principal component analysis (PCA) in combination with similarity analysis. PCA was more effective in identifying small differences between fingerprints than similarity analysis based on the correlation coefficients (r) alone. Furthermore, multivariate data analysis was used to construct partial least squares (PLS) regression models for the prediction of TAC from fingerprint data of each species, and available data from two microplate TAC assays. The construction of the models was successful with reasonable errors (< 10%), and permitted the determination of compounds of interest for future research. These included compounds of known identity that had large positive contributions toward the predictions of TAC, or unknown compounds that had small UV signals, but relatively large positive contributions to the models. / AFRIKAANSE OPSOMMING: Die talle gesondheidbevorderingseienskappe van ekstrakte van Cyclopia spesies word gedeeltelik geassosieer met hul fenoliese samestelling. Huidige kwaliteitskontrolemaatreëls is nie in staat om die variasie wat in die fenoliese profiele van die spesies voorkom, te akkommodeer nie. Omvattende hoë druk vloeistof chromatografiese (HPLC) metodes is vir twee Cyclopia spesies, naamlik C. subternata en C. maculata, in hierdie studie ontwikkel vir beter karakterisering van die fenoliese samestelling van waterekstrakte van dié spesies. Die metodes moes ook geskik wees vir roetine analise van C. subternata en C. maculata ekstrakte op konvensionele HPLC instrumentasie, en vir die opstel van chromatografiese vingerafdrukke (fenoliese samestellingsprofiele) vir verdere data analise, soos gelykvormigheidsanalise en die voorspelling van die totale antioksidantkapasiteit (TAC). Twee HPLC metodes, wat van ’n ultraviolet-diode detektor (DAD) gebruik maak, is ontwikkel deur ’n sistematiese benadering te volg. Die onderskeie metodes is vir die ontleding van waterekstrakte van groen (ongefermenteerde) en gefermenteerde plantmateriaal van C. subternata en C. maculata gevalideer. Ongeag die spesie is optimale skeiding met dieselfde kolom, mobiele fase en kolom-temperatuur bereik, maar met verskillende mobiele fase gradiënte. Analise met massaspektrometrie (MS) en tandem MS het die teenwoordigheid van fenoliese verbindings, wat voorheen in Cyclopia spesies geidentifiseer is, bevestig. Verder is ook ’n aantal verbindings vir die eerste keer in Cyclopia tentatief geidentifiseer. Dit sluit apigenien-6,8-di-C-glukosied, 3- hidroksiefloretien-30,50-di-C-heksosied, eriodiktiol-di-C-glukosied, iriflofenoon-di-O,C-heksosied, hidroksiemangiferien en hidroksie-isomangiferien in. Vervolgens is ’n groot aantal ewekansig gekose waterekstrakte van beide groen C. subternata (n = 64) en C. maculata (n = 50) plantmateriaal geanaliseer, en groot kwantitatiewe variasie op intra- en inter-spesievlak waargeneem. Cyclopia maculata ekstrakte het byvoorbeeld byna ses maal die mangiferieninhoud van C. subternata ekstrakte gehad. HPLC-DAD analise van die ekstrakte het duplikaat vingerafdrukke van elke ekstrak geproduseer, wat vir verdere data analise gebruik is. Die chromatografiese vingerafdruk van ’n bioaktiewe ekstrak van elke spesie was by die onderskeie datastelle ingesluit. Gelykvormigheidsanalise is tussen vingerafdrukke van die ewekansig gekose ekstrakte en die ooreenstemmende aktiewe ekstrak uitgevoer. Vir elke spesie is ’n aantal “aktiewe” ekstrakte aangewys (n = 15 vir C. subternata en n = 45 vir C. maculata). Die verbindings wat potensieel verantwoordelik kan wees vir die aktiwiteite is met behulp van hoofkomponentontleding (PCA) in kombinasie met gelykvormigheidsanalise, tentatief aangewys. PCA was egter meer effektief om klein verskille tussen vingerafdrukke aan te dui, in vergelyking met gelykvormigheidsanalise wat slegs op die korrelasie koëffisiënt (r) gebaseer is. Meerveranderlike data analiese is gebruik om “gedeeltelike kleinste kwadrate” (PLS) regressiemodelle, vir die voorspelling van die TAC van beide spesies te bou. Die voorspelling is gebaseer op hul vingerafdruk data en TAC data van twee TAC mikroplaat metodes. Die model-konstruksie was suksesvol met aanvaarbare voorspellingsfoute (< 10%). Verbindings van belang kon ook bepaal word. Dit sluit bekende verbindings in wat groot positiewe bydraes ten opsigte van die voorspelling van TAC getoon het, asook ongeidentifiseerde verbindings wat klein UV-seine getoon het, maar relatiewe groot bydraes tot die modelle gehad het.
313

Contribution à l'étude de la séparation des protéines par chromatographie d'échange d'ions en milieu complexe. Effet du poids moléculaire sur l'équilibre et la cinétique de rétention / Contribution to the study of protein separation by ion exchange chromatography in complex medium. Effect of molecular weight on equilibrium and kinetic uptake

Wakkel, Manel 02 July 2015 (has links)
La séparation et la purification de biomolécules à partir de milieux bruts, végétaux ou biologiques, est un sujet vaste etcomplexe. De sa compréhension et de son développement dépendent des enjeux industriels, et notamment le completdéveloppement des procédés biotechnologiques, les procédés de séparation, ou downstream processes, constituant environ 80% des coûts totaux de ces procédés. Ce travail se veut une contribution à ces problématiques. Il a été motivé par des résultatsobtenus au préalable dans le laboratoire qui montraient qu’il est possible de récupérer une protéine de très grande taille àpartir d’un milieu réel végétal par l’application d’une seule opération chromatographique (Kerfai, 2011). Suite à ce résultat,des hypothèses ont été énoncées, auxquelles ce travail essaie de répondre : quel(s) mécanisme(s) peuvent expliquer cerésultat ? Existe-t-il une localisation spécifique pour la fixation de la molécule sur l’échangeur d’ions qui rend plus simple etefficace sa récupération lors de l’étape d’élution ? Ainsi, notre objectif a été de progresser dans la connaissance des aspectsfondamentaux de la chromatographie d’échange d’ions appliquée à la séparation des protéines à partir d’un milieu brut.Notamment, l’influence de la présence d’autres protéines dans le milieu a été analysée, et ce dans le cas particulier deprotéines de poids moléculaire très différents, comme c’était le cas dans le travail précédemment cité. Des approches variées,théoriques et expérimentales à différentes échelles sur des milieux réels ou synthétiques, ont été appliquées et parfoisdéveloppées, pour essayer de répondre à ces questions. A l’échelle du procédé, une méthode statistique d’analyse desdonnées (Analyse en Composantes Principales ou ACP) a été menée, dont l’exploitation reste délicate. A l’échelle dulaboratoire, l’étude de l’équilibre et de la cinétique d’échange d’ions a été menée sur des solutions synthétiques de deuxprotéines : la sérum albumine bovine (BSA) (en tant que protéine de référence, couramment étudiée) et la ferritine (protéinede stockage du fer) de point isoélectrique proche de celui de la BSA mais de masse molaire plus élevée. Les résultatsmontrent que des modèles relativement classiques peuvent être appliqués, y compris pour les protéines de très grandes tailles,pour expliquer les aspects cinétiques de l’échange. Le couplage des flux de matière des protéines à l’intérieur des particulesde l’échangeur est très probable, malgré des diffusivités très différentes. Interpréter les résultats d’équilibre reste bien plusardu. La concentration en sel ou la présence de la BSA n’ont que très peu d’effet sur la rétention de la ferritine à l’équilibre.En revanche, la présence de la ferritine affecte très fortement la rétention de la BSA (pourtant plus favorable). Parmi lesphénomènes suggérés dans la littérature, l’effet Vroman a été recherché, mais il n’a pas été constaté dans le système pour lesconditions de travail utilisées. Les isothermes d’adsorption en conditions compétitives n’ont pas pu être simulées par lesmodèles habituels (comme l’isotherme multi-constituants de Langmuir), alors que celles des protéines seules sont tout à faitclassiques. En outre, un blocage partiel des pores de la résine par la ferritine reste probable, empêchant la diffusion de laBSA. Afin de vérifier ce dernier point, une méthodologie a été développée afin d’observer à l’échelle microscopique lesprofils de concentration des éléments représentatifs du système (P, Fe, Cl…) dans les particules. Cette méthode qui se trouveà un stade très avancé de développement, n’a pas encore permis de conclure faute de sensibilité suffisante des sondes àdisposition. / Bioseparations from crude media, vegetable or biological, is a large and complex subject. Future industrial issues depend ontheir understanding and development, namely for biotechnological processes as downstream processes represent up to 80 %of their total cost. This work hopes to contribute to these general questions. It is justified by previous results obtained in thelaboratory showing that it is possible to recover a high molecular weight (HMW) protein from a complex vegetal juice in justone chromatographic operation. Hypotheses have been formulated, to which this work tries to answer: what mechanism couldexplain this behaviour? Is-there a specific location inside particles for the uptake of such protein, facilitating the recoveryduring elution step? Our objective has been to progress on the knowledge of fundamental questions concerning ion-exchangechromatography and their applications for proteins recovery from complex media. The effect of the other proteins in solutionhas been analysed, specifically in the situation where both proteins have a very different molecular weight, as in the previouscited work. Theoretical and experimental approaches, at various scales, have been applied or developed on real or syntheticsystems in order to answer some of these questions. At the process scale, a statistical method for data analysis (PrincipalComponent Analysis or PCA) has been applied. The complete interpretation of its results remains very hard. At thelaboratory scale, equilibrium and kinetics of ion exchange have been studied for synthetic solutions of two proteins: bovineserum albumin (BSA) (as reference protein widely studied), and ferritin (iron storage protein) having similar isoelectric pointas BSA but with higher molecular weight. Classical models for ion-exchange kinetics can explain the experimental results,even for HMW proteins. Mass transfer fluxes seem to be coupled for both proteins, even if they have usually very differentdiffusivities. The interpretation of equilibrium results is much more difficult. Equilibrium uptake of ferritin is not, or lightly,influenced by salt concentration or BSA content. Nevertheless, the presence of ferritin in the medium affects strongly BSAequilibrium uptake (however more favourable). Among the phenomena suggested in the literature, the Vroman effect hasbeen researched but it does not take place under the experimental conditions applied. Simulation of multi-componentisotherms has not been possible by classical models (such as multi-component Langmuir isotherm), while protein isothermsin single solution are standard. Besides, a partial blockage of the resin pores by ferritin is possible, preventing BSA diffusion.Therefore, a methodology has been developed at the microscopic scale, with the aim to observe concentration profiles forrepresentatives elements (P, Fe, Cl …) inside particles. The method, well developed, does not allow to conclude for themoment, because the probes used were not sensible enough.
314

Desenvolvimento de método para determinação de acetaldeído em álcool etílico hidratado combustível por cromatografia líquida de alta eficiência com detecção eletroquímica

Okumura, Leonardo Luiz [UNESP] January 2003 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:29:09Z (GMT). No. of bitstreams: 0 Previous issue date: 2003Bitstream added on 2014-06-13T19:38:10Z : No. of bitstreams: 1 okumura_ll_me_araiq.pdf: 737796 bytes, checksum: fb5e89571c23b9fd419cea4f1ac1559e (MD5) / O comportamento cíclico voltamétrico do acetaldeído e seu derivado foi estudado em eletrodo de gota pendente de mercúrio e carbono vítreo. Este estudo foi utilizado na otimização das condições para a detecção eletroquímica desses compostos por Cromatografia Líquida de Alta Eficiência (C.L.A.E.). O acetaldeído foi derivado com 2,4-dinitrofenilhidrazina (DNPHi) e o produto, a 2,4-dinitrofenilhidrazona do acetaldeído (AcH-DNPHo) foi eluida e separada por coluna de fase reversa C18 em condições isocráticas com fase móvel contendo uma mistura binária de metanol-solução aquosa de cloreto de lítio (LiCl) com concentração de 1,0 ´ 10-3 M (80:20% v/v) e vazão de 1,0 mL min-1. A detecção eletroquímica (D.E.) do AcH-DNPHo foi realizada por C.L.A.E. com potencial fixado em + 1,0 V vs eletrodo de referência Ag/AgCl. O método proposto foi simples, rápido (tempo de análise 7 min.), com limite de detecção 3,80 mg L-1, altamente seletivo, e reprodutível [desvio padrão relativo 8,2% (n=12)]. A curva analítica do AcH-DNPHo foi linear na faixa compreendida de 0 - 300 mg L-1, com índice de correlação linear 0,9998. A concentração de acetaldeído determinada em amostras de álcool combustível foi de 83 – 341 mg L–1 com desvio padrão de 1 – 6 %, na variação da área de pico e recuperação superior a 99%. A quantidade do teor de acetaldeído encontrado nestas amostras foi significativamente alta e os resultados obtidos foram comparados com o método de detecção espectrofotométrica (UV/Vis) / The cyclic voltammetric behaviour of acetaldehyde and their derivatives has been studied at a hanging drop mercury and glassy carbon electrode. This study was used to optimise the conditions for the electrochemical detection of these compounds following high-performance liquid chromatographic (H.P.L.C.) separation. The acetaldehyde was derivatized with 2,4-dinitrophenylhydrazine (DNPHi) and the product 2,4-dinitrophenylhydrazone (AcH-DNPHo) was eluted and separated by reversed-phase column C18 in isocratic conditions with mobile phase containing binary mixture of methanol-chloride littium aqueous solution with concentration 1,0 ´ 10-3 M (80:20% v/v) and flow rate of 1.0 mL min-1. The electrochemical detection (E.D.) of AcH-DNPHo was performed by H.P.L.C. set at +1.0 V vs Ag/AgCl as reference electrode. The proposed method was simple, rapid (analysis time 7 min), with detection limit 3.80 mg L-1, highly selective, and reproducible [relative standard deviation 8.2 % (n=12)]. The calibration graph for AcH-DNPHo was linear in the range of 0 – 300 mg L-1 with correlation coefficient 0,9998. The concentrations of acetaldehyde determined in fuel alcohol samples was in the range of 83 – 341 mg L–1 with standard deviation of 1 – 6 %, in peak area variation and analytical recovery was >99%. The amount of acetaldehyde content found in these samples was significantly higher and the results obtained were compared to the spectrofotometric detection method (UV/Vis)
315

Avaliação de propriedades físicas e químicas de óleos vegetais comestíveis empregando-se análise multitabelas / Evaluation of the physical and chemical properties of edible vegetable oils using multiblock analysis

Rosa, Larissa Naida 24 February 2017 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Atualmente têm-se verificado um aumento acentuado na demanda de mercado em relação a óleos vegetais das mais diversas fontes naturais. Os óleos vegetais são extraídos na sua maioria das sementes de plantas, formados por ésteres de glicerina e uma mistura de ácidos graxos, esteróis, tocoferóis e resíduos minerais. Medições rápidas e não destrutivas dos parâmetros relacionados com a qualidade de alimentos estão avançando devido ao progresso da espectroscopia, pois permitem aos pesquisadores obter informações importantes dos componentes químicos e físicos dos alimentos. Nesse sentido, a quimiometria colabora para a transformação dos sinais analíticos de amostras complexas em informações úteis, o método quimiométrico empregado nos estudos foi a análise multitabelas (ComDim), cujo objetivo foi avaliar tabelas (ou matrizes) de dados adquiridos para as mesmas amostras (isto é, um conjunto de matrizes de dados com o mesmo número de linhas, mas não necessariamente o mesmo número de variáveis). Com a aplicação do método ComDim foram obtidos gráficos informativos que mostraram a relação entre as amostras e suas variáveis, além de permitir avaliar em qual das tabelas analisadas encontra-se a informação predominante. Como resultado da primeira pesquisa, o método ComDim permitiu realizar um reconhecimento de padrão não supervisionado auxiliando na identificação de semelhanças e diferenças entre as amostras de óleos e azeites de oliva. Para os óleos de arroz foi possível correlacionar as regiões espectrais do UV-Vis e NIR, bem como as análises físico químicas inferindo sobre início e estágios mais avançados das reações de degradação. . / We currently have a marked increase in market demand for vegetable oils from a variety of natural sources. Vegetable oils are extracted mostly from plant seeds, consisting of glycerol esters and a mixture of fatty acids, esters, tocopherols and mineral residues. Fast and non-destructive measurements of food quality data are advancing due to the progress of spectroscopy, for research researchers to obtain important data of the chemical and physical components of food. In this sense, chemometrics collaborates to transform the analytical signals of complex samples into useful information, the chemometric method used in the studies was the multi-table analysis (ComDim), whose objective was to evaluate tables (or matrices) of data acquired for the same samples (that is, a set of data arrays with the same number of rows, but not necessarily the same number of rows). With the application of the ComDim method, informative graphs were obtained that showed the relation between the samples and their variables, besides allowing to evaluate in which of the analyzed tables the predominant information is found. As a result of the first research, the ComDim method allowed the realization of an unsupervised pattern recognition, aiding in the identification of similarities and differences between samples of oils and olive oils. For rice oils it was possible correlates UV-Vis and NIR spectral regions, also physical-chemical analysis and attribute the start and advanced stages for degradation reactions.
316

Contribuição ao estudo fitoquímico de Richardia grandiflora (Cham.&Scltdl.) Steud.(Rubiaceae)

Pereira, Lázaro Robson de Araújo Brito 28 February 2011 (has links)
Made available in DSpace on 2015-05-14T13:00:16Z (GMT). No. of bitstreams: 1 parte1.pdf: 1831171 bytes, checksum: 228d3280be1b514141d6d1e465f701b6 (MD5) Previous issue date: 2011-02-28 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Medicinal plants are an alternative therapy for the prevention and cure of disease since the beginning of humanity. This relationship is so intimate that mingles with the own evolution of man. Brazil has a great diversity on plants that possess non-researched medicinal potential and are promising sources of therapeutic and pharmacological innovations. The Rubiaceae family is considered the biggest one of the order Gentianales, presenting around 637 genera and 10,700 species. The species Richardia grandiflora (Cham. & Schltdl.) Steud., known popularly as ervanço , poaia or ipeca-mirim , has ethnopharmacological indications to use as decoction against hemorrhoids and as vermifuge. Aiming at contributing to the chemotaxonomic study of the the family Rubiaceae and considering the small amount of data in literature about the chemical constitution of the species Richardia grandiflora, the latter was submitted to a phytochemical study to isolate its chemical constituents, through usual chromatographic methods, and after identifying them by means of spectroscopic methods such as IR and 1H and 13C NMR, besides comparison with literature data. Three constituents were isolated through this phytochemical study: oleanolic acid, ursolic acid, unpublished in the species, and 132-hydroxy-(132-S)-phaeophytin (a), isolated for the first time from the genre. / As plantas medicinais constituem uma alternativa terapêutica para a prevenção e cura de doenças desde o início da humanidade. Tal relacionamento é tão íntimo que se confunde com a própria evolução do homem. O Brasil tem grande diversidade de plantas com potenciais medicinais, não-pesquisadas, e que são promissoras fontes de inovações terapêuticas e farmacológicas. A família Rubiaceae, considerada a maior da ordem Gentianales, possui cerca de 637 gêneros e 10.700 espécies. A espécie Richardia grandiflora (Cham. & Schltdl.) Steud., conhecida popularmente como ervanço, poaia ou ipeca-mirim, tem indicações etnofarmacológicas para uso contra hemorróidas e como vermífugo na forma de decocto. Visando a contribuir com o estudo quimiotaxonômico da família Rubiaceae e tendo em vista a pouca quantidade de dados na literatura acerca da constituição química da espécie Richardia grandiflora, esta foi submetida a um estudo fitoquímico para o isolamento de seus constituintes químicos, através dos métodos cromatográficos usuais, e posterior identificação estrutural dos mesmos, utilizando-se os métodos espectroscópicos de IV e RMN 1H e 13C, além de comparações com modelos da literatura. Deste estudo foram isolados e identificados três constituintes: o ácido oleanólico, o ácido ursólico, inéditos na espécie, e a 132-hidroxi- (132-S)-feofitina (a), inédita no gênero.
317

Triagem fitoquímica e farmacológica e formulação de nanopartículas de produtos derivados de Passiflora serratodigitata L. / Phytochemical and pharmacological screening and nanoparticle formulation of products derivated from Passiflora serratodigitata L.

Marc Strasser 25 February 2011 (has links)
Introdução: A família Passifloraceae se destaca dentre os principais grupos de plantas nativas utilizadas na medicina popular brasileira. Este trabalho descreve a química e farmacologia de Passiflora serratodigitata L. Objetivos: Determinar os principais grupos de substâncias ativas, quantificar flavonóides, estabelecer um perfil cromatográfico em cromatografia líquida (CLAE), estudar as atividades antiúlcera, anti-inflamatória e antioxidante do extrato bruto e frações de Passiflora serratodigitata, e comparar a atividade antiúlcera com uma formulação nanoencapsulada. Material e Métodos: Folha e caules secos de P. serratodigitata foram fornecidos pelo Instituto Agronômico de Campinas. O extrato bruto (EB) foi preparado por maceração seguida de percolação, e foi fracionado por partição líquido-líquido nas frações hexano, diclorometano, acetato de etila e aquosa. A triagem fitoquímica se direcionou para os principais grupos químicos relatado na família. O perfil cromatográfico para flavonóides foi realizado em cromatografia em camada delgada e CLAE. A quantificação de flavonóides foi determinada por espectrofotometria. As atividades anti-inflamatória e antiúlcera foram estudada em ratos Wistar. O modelo de úlcera aguda contou com lansoprazol como controle e os resultados foram analisados pelos softwares ImageProPlus® e XLStat®. A quantificação de flavonóides foi realizada em espectrofotômetro. A atividade antioxidante foi avaliada pela redução do DPPH. A formulação nanoparticulada foi caracterizada físico-quimicamente (tamanho de partícula, distribuição, potencial Zeta e eficiência de encapsulamento), e foi realizada uma comparação entre a atividade antiúlcera das nanopartículas com seus respectivos extratos não encapsulados. Resultados: A triagem fitoquímica revelou a presença de alcalóides, flavonóides e taninos. Os perfis cromatográficos apresentaram a presença de vários flavonóides, com predomínio na fração acetato de etila, e revelaram a presença de cinco compostos majoritários. Um destes compostos foi isolado, e apresentou estrutura semelhante ao neoflavonóide seratina, encontrada em literatura. A atividade anti-inflamatória apresentou resultado significativo apenas na dose de 400 mg/kg de EB, mas nenhum dos mediadores inflamatórios estudados foi inibido. A atividade antioxidante apresentou resultados satisfatórios, sendo a fração acetato de etila e o EB com atividade mais pronunciada, em convergência com a maior quantidade de flavonóides presentes nesses extratos. A atividade antiúlcera apresentou resultados extremamente significativos, com inibição total de úlcera para a fração acetato de etila, uma inibição superior a 70% para o EB e uma dose-dependência de inibição na fração aquosa. As nanopartículas formadas apresentaram distribuição unimodal de tamanho, potencial Zeta favorável e eficiência de encapsulamento superior a 80%. A atividade antiúlcera revelou proteção semelhante em doses dez vezes menores. Conclusões: Passiflora serratodigitata L. possui flavonóides, taninos e alcalóides. O perfil em CLAE acusou a presença de cinco compostos majoritários. O EB e as frações mais ricas em flavonóides apresentaram expressiva atividade gastroprotetora in vivo. As nanocápsulas apresentaram atividade semelhante em doses menores. / Introduction: The Passifloraceae family stands out among the main groups of native plants used in Brazilian folk medicine. This work describes chemical and pharmacological characterization of Passiflora serratodigitata L. Objectives: Determine the main groups of active substances, the total flavonoid content, establish a chromatographic profile in high performance liquid chromatography (HPLC), study the antiulcer, anti-inflammatory and antioxidant activities of the hydroalcoholic crude extract and its fractions of Passiflora serratodigitata, and compare the antiulcer activity with a nanoencasulated formula. Material & Methods: Dried leaves and stem of P. serratodigitata were provided by Instituto Agronômico de Campinas. The hydroalcoholic crude extract (HE) was prepared by maceration followed by percolation, and then it was fractioned by liquid-liquid extraction into hexane, dichloromethane, ethyl acetate and aqueous extracts. The phytochemical screening was directed to main groups presented in the family. The chromatographic profile for flavonoids was performed by thin-layer chromatography and HPLC. The flavonoid quantification was determinated by spectrophotometry. The antiulcer activity was studied in Wistar rats for three different HE ethylacetate and aquous fractions dosages, using lansoprazole as control. The ulcer was induced by an acidified ethanol solution (acute ulcer model), and the results were analyzed by the software ImageProPlus® and XLStat®. The flavonoid quantification was made by spectrophotometry. The anti-inflammatory activity was studied in Wistar rats. The antioxidant activity was studied by the DPPH method. Nanoparticle were physic-chemically characterized (size distribution, Zeta potential and encapsulation efficiency), and a comparison between nanoparticle and plant extracts\' antiulcer activity was performed. Results: The phytochemical screening revealed the presence of alkaloids, flavonoids and tannins. The chromatographic profile showed the presence of various flavonoids. The HPLC assay showed a major presence of flavonoids in ethyl acetate and aqueous fractions, and revealed five main components, one of which was identified as similar to the neoflavonoid serratin. The antiulcer activity showed a protection of about 73% for all doses of HE and total protection for the ethyl acetate and aqueous extracts. The flavonoid quantification reported 12.9% of flavonoids in HE, 11,9% in the ethyl acetate fraction, and 3.8% in the residual water fraction. The anti-inflammatory activity showed significant results only for crude extract dose of 400 mg/kg, but none of the inflammation mediators studied were inhibited. For the antioxidant activity, results of EC50 for ethyl acetate fraction and crude extract were better when compared to residual water fraction, but not to Trolox®. The nanoparticle formulation originated nanocapsules with unimodal size distribuition, negative zeta potential, and antiulcer activity in doses ten times lower. Conclusions: Passiflora serratodigitata L. contains alkaloids, tannins and flavonoids. The HPLC analysis determined the presence of five major flavonoids. The CE and its most flavonoid-rich fractions showed an expressive in vivo gastric mucosa protection against acidified ethanol induced lesion.
318

Resolução enantiomérica do secnidazol / Enantiomeric resolution of secnidazole

Nascimento, Ana Carolina 20 August 2018 (has links)
Orientador: Cesar Costapinto Santana / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-20T14:12:19Z (GMT). No. of bitstreams: 1 Nascimento_AnaCarolina_M.pdf: 2361694 bytes, checksum: bcd5c25d65fe1d7ac8a8666d6f13c023 (MD5) Previous issue date: 2012 / Resumo: O secnidazol corresponde à formulação 1-(hidroxipropil)-2-metil-5-nitroimidazol e possui espectro de atividade contra microorganismos anaeróbicos e eficácia no tratamento de amebíase, giardíase, tricomoníase e vaginose bacteriana. Ele é comercializado na forma racêmica, isto é, na proporção 1:1 dos seus enantiômeros R e S. Não é oficial em nenhuma farmacopeia. Estudos relatam que para alguns imidazóis o enantiômero R apresenta maior atividade biológica frente ao enantiômero S. Portanto a separação do secnidazol é importante para testes biológicos comparativos de efeitos colaterais. Inserindo-se neste contexto, foi desenvolvido este trabalho de pesquisa com o intuito de estudar a resolução enantiomérica do fármaco secnidazol pela técnica de cromatografia líquida de alta eficiência utilizando coluna recheada com fase estacionária tris(3,5-dimetilfenilcarbamato) de amilose. Experimentos de pulsos com soluções diluídas foram realizados variando a vazão de fase móvel de 1,0 a 2,5 mL/min e as temperaturas de 20 a 35°C. Os resultados mostraram alta eficiência, com número de pratos superando 1000 e fatores de separação na ordem de 7,0. Os valores negativos de 'delta'H e 'delta'S* indicam que a adsorção dos enantiômeros da fase móvel na fase estacionária é entalpicamente favorável. Experimentos a altas concentrações (condições de sobrecarga) foram realizados com a finalidade de determinar as isotermas não-lineares pelo método da análise frontal e também os perfis de eluição sob estas condições. As isotermas de adsorção apresentaram comportamento não-linear e o modelo de Langmuir foi bem correlacionado aos dados experimentais de equilíbrio no intervalo de concentração analisado. A partir da metodologia shortcut foram obtidos os parâmetros operacionais da unidade leito móvel simulado. As purezas alcançadas para as correntes de extrato e refinado foram 85,50% e 72,50%, respectivamente / Abstract: The chemical formula of secnidazole is 1-(hydroxypropyl)-2-methyl-5-nitroimidazole. It acts activity against anaerobic microorganisms and is effective in the treatment of amebiasis, giardiasis, trichomoniasis, and bacterial vaginosis. It is marketed in the racemic form, that is, proportion 1:1 of their R and S-enantiomers. It's not officially recognized by any pharmacopoeia. Studies have reported that for some imidazoles the R-enantiomer has a higher biological activity than the S-enantiomer. For this reason the separation of secnidazole is important for comparative biological tests of side effects. It is in this context that this research was developed in order to study the enantiomeric resolution of drug secnidazole by the technique of high performance liquid chromatography using stationary phase column packed with amylose tris (3, 5- dimethylphenylcarbamate). Pulse experiments with dilute solutions were conducted by varying the mobile phase flow (1.0 to 2.5 mL/min) and temperature (20 to 35 °C). The results revealed high efficiency, with number of plates overcoming 1000 and selectivities in the order of 7.0. The negative values of 'delta'H and 'delta'S* indicates that the enantiomer adsorption from the mobile phase to stationary phase is enthalpically favorable. Experiments in overloaded conditions were realized to obtain the equilibrium adsorption isotherms by frontal analysis, as well overload elution profiles. The adsorption isotherms shown a nonlinear behavior and the Langmuir model was well correlated to equilibrium experimental data in the range of investigated concentration. From the shortcut method operating parameters were obtained to the simulated moving bed unit. The purities reached for the extract and raffinate lines were 85.50% and 72.50% , respectively / Mestrado / Desenvolvimento de Processos Biotecnologicos / Mestra em Engenharia Química
319

The phytochemistry of several South African aloe species

McCarthy, Terence John January 1967 (has links)
Introduction: Despite the tremendous advances made with regard to synthetic organic medicinals within the last two decades, heavy reliance is still placed on plant products. This is especially true of the anthracene derivatives used medicinally as purgatives, and which are derived principally from senna, cascara, rhubarb, frangula and aloes. While particular attention has been paid to the chemistry of the former group in recent years, aloes has been largely neglected, possibly due to the fact that the Aloe species are confined largely to areas where extensive research facilities are lacking, such as Africa , India and the West Indies. Thus research in Europe has been confined largely to the lump aloes of commerce, derived from relatively few species. In 1953 a comprehensive report by Hodge (103) appeared on "The Drug Aloes of Commerce, with Special Reference to the Cape Species". Hodge observed that South Africa abounds in species just as abundant as A.ferox, (which is the prime source of Cape aloes), and advised that a systematic chemical survey might show certain of these to be not only higher yielders of bitter aloetic juice but also sources of a superior drug product. Consequently an investigation along these lines is presented here, and it is observed that several species apart from A.ferox not only contain aloin, but also yield a large volume of aloetic juice. Only pharmacologic studies can reveal if the juice of these species is as safe as that of A.ferox, but without doubt they could be used for the extraction of crystalline aloin. Concurrently, the distribution of the Aloe resins, said by some to be purgative themselves, has been studied. The investigation has revealed that the structurally similar compound homonataloin enjoys an equally wide distribution as aloin. However, almost invariably it is confined to small species yielding little aloetic juice, apart from which nothing is known regarding its pharmacologic properties. It is interesting to note that the resin distribution in the homonataloin-containing species is very similar to that of the aloin-containing species, but differs widely from. that of the species containing neither of these principles. Apart from aloin and homonataloin, aloinoside and chrysophanol also occur in Aloe species, and together with the resins, these indicate that when all the South African Aloe species have been investigated, they may well be of chemotaxonomic value. Within the comparatively short space of the last decade some work has been performed on aspects of the metabolism of such anthracene-containing species as Rheum, Rhamnus and Rumex. These investigations have shown that the anthracene derivatives are not merely waste products, but perform definite metabolic functions. The latter portion of this work has been devoted to this relatively neglected aspect of the Aloe species.
320

Recherche de conditions alternatives à l’utilisation de solvants chlorés en Chromatographie Liquide Non-Aqueuse à Polarité Inversée de Phases. Application à l’analyse des lipides présents dans les milieux complexes / Search for alternative conditions for the use of chlorinated solvents in Non-Aqueous Reversed Phases liquid chromatography. Application to the analysis of lipids present in complex media

Hmida, Dorra 22 July 2016 (has links)
Déterminer la composition en triacylglycérols des huiles végétales est un défi important à relever aussi bien en biologie végétale que dans le domaine médical ou celui de l’industrie agro-alimentaire. La chromatographie en phase liquide à polarité inversée de phases en milieu non aqueux (NARP-LC) est la méthode la plus utilisée, avec cependant une utilisation récurrente de solvants chlorés. Le premier objectif de ce travail a été de proposer des conditions analytiques alternatives n’utilisant pas de solvants chlorés. Pour ce faire, nous avons établi le diagramme de force éluante sur phases stationnaires en C18 des phases mobiles binaires constituées d’acétonitrile comme solvant faible et de divers solvants forts (acétone, iso-propanol, acétate d’éthyle, butanol) à quatre températures différentes (25, 43, 63 et 85°C). La comparaison dans des conditions iso-éluantes de l’analyse de 9 huiles de graines contenant une large gamme de TAG nous a permis de montrer que le mélange MeCN/BuOH 74/26 à 25°C est le meilleur choix, en terme de sélectivité pour l’analyse des TAG. Ce qui répond à notre premier objectif. Dans un second temps, nous avons comparé le potentiel séparatif des phases stationnaires de nouvelle génération à petit diamètre de particules, partiellement ou totalement poreuses. L’optimisation des conditions chromatographiques nous a permis de décrire deux systèmes chromatographiques, très performants, en termes d’efficacité et de rapidité. Le premier permet la séparation de TAG contenant des acides gras polyinsaturés isomères de position en C18 : 3 et C18 : 2. L’identification de ces isomères particuliers a été réalisée grâce à la synthèse d’informations complémentaires, obtenues en GC/MS, LC/MS ainsi que l’utilisation de lois de rétention chromatographiques. En outre, ce travail nous a permis de proposer un tableau récapitulatif regroupant un très grand nombre de TAG, qui n’ont jamais été décrits à notre connaissance. Le second permet une analyse rapide de l’huile d’olive, en moins de 5 min, tout en respectant les consignes qualitatives imposées par l’organisme «Conseil Oléique International (COI)». Comparée aux méthodes officielles couramment utilisées, elle mérite d’être proposée comme méthode de référence pour le contrôle de qualité de l’appellation de ces huiles. / The determination of triacylglycerols in vegetable oils is an important challenge in plant biology, in the medical field, and in food industry. Nowadays, non-Aqueous Reversed Phase Liquid Chromatography (NARP-LC) using chlorinated solvents is commonly used for this purpose. The first objective of this work was to develop alternative analytical conditions that can avoid using chlorinated solvents. In a first step, by using C18 stationary phases, we have established the eluotropic solvent strength scale as a function of temperature of several binary mobile phases consisting of acetonitrile as weak solvent and various strong solvents including acetone, isopropanol, ethyl acetate, and butanol. The comparison of the results obtained under iso-eluotropic conditions for nine seed oils containing a wide range of TAG enabled us to show that the MeCN/BuOH (74/26, v/V) mixture operating at 25 °C are the best mobile phase conditions for TAG analysis, in terms of selectivity, thus avoiding the use of chlorinated solvents. In a second step, we compared the separation of TAGs on new generation of fully or partially porous stationary phase particles of small diameter. After optimizing the separating conditions, the obtained data allowed us to propose two highly efficient chromatographic systems. The first system enables the efficient separation of C18:3 and C18:2 positional isomers of C18 polyunsaturated fatty acids containing TAG. For the identification of these TAG isomers, it was necessary to combine the data obtained by GC-MS and LC -MS as well as the data obtained by the application of some chromatographic retention laws. Taken together, these results allowed us to provide a list containing a large number of TAG unknown to date. The second system allows rapid analysis of olive oil in less than 5 min. This system obeying the guidelines of the International Olive Council can be proposed as a candidate reference method for rapid quality control of olive oils.

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