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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.
571

Synthesis of the ABC fragment of pectenotoxin-4

Lipinski, Radoslaw Michal January 2012 (has links)
This thesis details the application of two synthetic methodologies, developed by the Donohoe group, to the synthesis of the ABC fragment of pectenotoxin-4, a macrolide marine natural product that consists of 19 stereogenic centres, three tetrahydrofuran rings, one spiroketal and one bicyclic ketal embedded within a 26-membered macrocycle. Pivotal to the developed synthetic route was the utilisation of an unprecedented cascade osmium catalysed oxidative cyclisation for the construction of two THF rings (the BC ring system). After successfully developing a model system for the synthesis of the AB anomeric 6,5 spiroketal, which involved the employment of a hydride shift initiated oxo carbenium ion formation followed by intramolecular spiroketalisation, the developed system was then applied to the fully elaborated synthesis of the ABC fragment. The synthesis of the ABC fragment of pectenotoxin-4 was completed in 20 linear steps, with an overall yield of 3.3%.
572

Using molecular oxygen in synthesis : applications in lignin valorisation and natural product synthesis

Lancefield, Christopher Stuart January 2015 (has links)
The first part of this thesis describes my research towards the valorisation of lignin. Due to environmental and political pressures, there has been a drive to start the transition from a fossil fuel based economy to a renewable based one. This will require the development of novel routes to renewable chemicals, one source of which may be the biopolymer lignin. Through the synthesis of advanced lignin model compounds, the chemistry of real lignin is explored. This work culminates in the development of a novel method for the depolymerisation of real lignin to simple mixtures of aromatic chemicals that could be useful building blocks for the chemical industry. One of the key steps in this process is the oxidation of the β-O-4 linkages in lignin using catalytic amounts of DDQ and molecular oxygen as the terminal oxidant. The second part of this thesis details the first synthesis of melohenine B and O-ethyl-14-epimelohenine B, two medium sized ring containing natural products. The key step in the synthesis of these natural products was the photo-sensitised oxidative cleavage of an indolic substrate by molecular oxygen. Additionally, the use of residual dipolar coupling (RDC) analysis for the conformational analysis of these molecules in solution has been explored. Finally, the absolute configurational assignment of the natural products was established and their biological activities investigated.
573

Ovlivnění kinas uplatňující se v patogenezi Alzheimerovy choroby. / Use of kinase modulation in the Alzheimerʼs disease pathogenesis.

Polzerová, Iveta January 2016 (has links)
Polzerová, I: Use of kinase modulation in the Alzheimer's disease pathogenesis. Diploma thesis, Charles University in Prague, Faculty of Pharmacy in Hradec Králové, Department of Pharmaceutical Botany and Ecology, Hradec Králové 2016, 91 p. Data used in this Diploma Thesis have been taken from foreigner scientific literary sources. It provides the summary of the not yet explored natural compounds from marine organisms with kinase inhibitory activity. The first chapter Alzheimer's disease describes a characteristic of the disease, its etiopathogenesis, risk factors and currently available treatment. At the beginning of the second chapter are mentioned new perspective approaches to treatment of Alzheimer's disease. Most of this chapter deals with kinases as potential therapeutic targets in the treatment of Alzheimer's disease. In the chapter, physiologic and pathophysiologic functions of GSK-3β and CK-1δ are described in the organism, and also, other kinases are mentioned which are involved in the pathogenesis of the disease. Next part dedicates analytical methods suitable for testing activity and inhibition of kinases in vitro and in silico, also deals with summary of the synthetic kinase inhibitors and characterizes an their properties. In this chapter is also described main part of this work - the...
574

The total synthesis of chamuvarinin

Morris, Joanne Charleen January 2013 (has links)
In 2004, the polyketide natural product, chamuvarinin (72) was isolated by Laurens et al. from the roots of Uvaria chamae, a member of the Annonaceae plant family. This unique tetrahydropyran containing acetogenin displayed potent levels of cytotoxic activity against the KB 3-1 cell line with an ED50 value of 0.8 nM. Upon initial isolation the relative and absolute stereochemical assignment of chamuvarinin (72) was unable to be readily achieved through ¹H and ¹³C NMR analysis. The initial synthetic route described herein has enabled the relative and absolute stereochemical determination of chamuvarinin (72) through the first total synthesis completed in 20 longest linear steps in 1.5% overall yield. A revised synthetic strategy towards chamuvarinin (72) was completed in 17 longest linear steps in 2.2% overall yield. The revised route facilitated the assembly of non-natural chamuvarinin-like analogues and their trypanocidal and cytotoxic activities have been assessed. The synthesis of these analogues has formed the basis of a more focussed study through the design and synthesis of simplified triazole (295), isoxazole (325) and butenolide triazole (305) analogues as potential Trypanosoma brucei (causative agent in African Sleeping sickness) inhibitors.
575

Adhésifs naturels à base de tannin, tannin/lignine et lignine/gluten pour la fabrication de panneaux de bois / Natural Adesives from Tannin, Tannin/Lignin and Tannin/Gluten for the Wood Panel Process

Navarrete Fuentes, Paola Jeannette 08 December 2011 (has links)
Lors de cette étude, différentes recherches ont été effectuées sur l'utilisation de divers matériaux naturels comme source de matière premières pour la fabrication de colles vertes pour l'industrie de panneau. Dans ce contexte, le travail a consisté à : (i) Evaluer le potentiel de différents tannins en provenance de déchets d'écorces et développer des colles à base de tanins avec différents durcisseurs.(ii) Evaluer le potentiel de lignines de différentes origines et développer des colles à base de tannin de mimosa et de lignine. (iii) Développer des colles à base de tannin et de protéine de gluten.(iv) Evaluer les émissions de formaldéhyde et d'autres composés organiques volatiles (COV) à partir de panneaux de particules fabriqués avec les colles naturelles mises au point précédemment.Les techniques d'analyses thermomécaniques, de spectroscopie CP-MAS 13C NMR, de matrix-assisted laser desorption/ionization mass spectrometry (MALDI-TOF) et de temps de gel ont été utilisées comme méthodes de travail pour l'évaluation et la caractérisation de ces colles. Les essais de cohésion interne pour l'évaluation de la résistance mécanique de la colle selon la norme EN -312 ont également été effectués.En ce qui concerne les émissions de formaldéhyde et des autres COV à partir de panneaux contentant des colles vertes, le recours à des techniques normalisées par chromatographie en phase gazeuse associée à un spectromètre de masse (GC-MS) et par chromatographie en phase liquide (HPLC) ont été privilégiées. / This study deals with some researches carried out about the use of various natural materials as a source of raw material for the manufacturing of green adhesives for the industry of panel. In this context, work consisted in:(i) Evaluation of the potential of various tannins coming from barks wastes and development of adhesives containing tannins and various hardeners.(ii) Evaluation of the lignin potential from various origins and development of adhesives containing tannin from mimosa and lignin.(iii) Development of adhesives containing tannin and gluten protein.(iv) Evaluation of formaldehyde and other volatile organic compounds (VOC) from particleboards manufactures with the natural adhesives previously developed.Thermomechanical analyses, spectroscopy CP-MAS 13C NRM, matrix- assisted laser desorption/ionization mass spectroscometry (MALDI-TOF) and gelling time techniques were performed for evaluation and characterization of these adhesives. Internal bond test for the evaluation of adhesives mechanical resistance according to the standard EN-312 were also carried out.Concerning formaldehyde and other VOC emissions from panels with green adhesives, the recourse to standardized techniques which are gas chromatography associated with a mass spectrometer (GC-MS) and high performance liquid chromatography (HPLC) were privileged.
576

Avaliação da atividade do óleo da semente de Pentaclethra macroloba (Willd.) Kuntze em relação à citotoxicidade, genotoxicidade e expressão gênica em célula de eucariotos

Cunha, Camila Lehnhardt Pires January 2019 (has links)
Orientador: Edson Luis Maistro / Resumo: Das sementes de Pentaclethra macroloba (Willd.) Kuntze, popularmente conhecida como Pracaxi, é possível a extração de um óleo que vem sendo utilizado no Brasil e em outros países para fins terapêuticos e cosméticos. Este vegetal é endêmico da região amazônica e frequentemente utilizado pela população ribeirinha como agente cicatrizante tópico, aplicado principalmente em parturientes e em picadas de serpentes, devido à sua ação antiofídica. Apesar do uso popular desse óleo, na literatura encontram-se poucos estudos avaliando seu potencial citotóxico e genotóxico. Frente a esta lacuna científica, o objetivo deste estudo foi investigar os efeitos deste óleo em células humanas HepG2/C3A in vitro, sob os aspectos de citotoxicidade, genotoxicidade, influência sobre o ciclo celular, apoptose e expressão de genes do metabolismo de xenobióticos e outras vias de sinalização celulares. Os testes do cometa e do micronúcleo foram utilizados na avaliação da genotoxicidade e mutagênese, citometria de fluxo na avaliação dos efeitos sobre o ciclo celular e apoptose, bem como a avaliação da expressão de alguns genes envolvidos nesses processos. Os resultados obtidos revelaram que o óleo não reduz a viabilidade celular nas concentrações de 31, 125 e 500 µg/mL. Nos ensaios do cometa e do micronúcleo, o óleo não apresentou efeitos genotóxico nas concentrações testadas. Além disso, a citometria de fluxo revelou que o óleo não induz apoptose nas células. A análise da expressão gênica revelou que, d... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: From the Pentaclethra macroloba (Willd.) Kuntze seeds, popularly known as Pracaxi, it is possible to extract an oil that is being used in Brazil and in other countries for therapeutic and cosmetic purposes. This plant is endemic to the Amazon region and is frequently used by the riverine population as a topical healing agent, applied mainly to parturients and snake bites due to its antiofidic action. Despite the popular use of this oil, there are few studies in the literature evaluating its cytotoxic and genotoxic potential. The objective of this study was to investigate the effects of this oil on human HepG2 / C3A cells in vitro, under the aspects of cytotoxicity, genotoxicity, influence on the cell cycle, apoptosis and expression of xenobiotic and other metabolism genes cellular signaling pathways. The comet and micronucleus tests were used in the evaluation of genotoxicity and mutagenesis, flow cytometry in the evaluation of effects on the cell cycle and apoptosis, as well as the evaluation of the expression of some genes involved in these processes. The results showed that the oil did not reduce cell viability at concentrations of 31, 125 and 500 μg / mL. In the comet and micronucleus tests, the oil had no genotoxic effects at the concentrations tested. In addition, flow cytometry revealed that the oil does not induce apoptosis in cells. Analysis of gene expression revealed that of all genes tested, those that underwent stimulation were responsible for the metabolism of x... (Complete abstract click electronic access below) / Doutor
577

Análise metabolômica aplicada à quimiotaxonomia de espécies do gênero Vernonia sensu lato (Vernonieae) / Metabolomics analysis applied to chemotaxonomic study of species from Vernonia sensu lato (Vernonieae)

Gallon, Marília Elias 31 May 2017 (has links)
Vernonia sensu lato é um dos maiores e mais complexos gêneros da tribo Vernonineae. A tribo pertence a família Asteraceae, a qual representa cerca de 10% da flora mundial e é considerada uma das maiores famílias dentre as plantas superiores. As espécies da tribo Vernonineae apresentam distribuição pantropical e são caracterizadas pela presença de lactonas sesquiterpênicas e flavonoides (principalmente flavonas e flavonóis). Ao longo dos anos, diversas classificações têm sido propostas para o gênero Vernonia s.l., porém ainda não há um consenso entre os pesquisadores. Nas classificações mais antigas, o gênero Vernonia s.l. inclui cerca de 1000 espécies (sensu Baker), distribuídas em seções e subseções; em uma divisão mais atual, essas espécies foram segregadas em vários novos gêneros e o gênero Vernonia, nas Américas, foi consideravelmente reduzido (sensu Robinson), ficando restrito a espécies distribuídas principalmente na América do Norte. Neste estudo, foram realizadas análises metabolômicas e estatísticas de espécies do gênero Vernonia s.l., pertencentes às subtribos Vernoniinae, Lepidaploinae e Rolandrinae, com o intuito de verificar se a abordagem metabolômica pode ser utilizada como uma ferramenta quimiotaxonômica e auxiliar nas classificações taxonômicas do gênero. A partir das impressões digitais metabólicas obtidas por UHPLC-UV-MS, foram realizadas análises estatísticas não-supervisionadas (HCA e PCA) e supervisionadas (OPLS-DA). A análise por HCA permitiu a identificação de quatro grupos principais, os quais sugerem que as espécies apresentaram tendência em se agruparem de acordo com os gêneros criados por Robinson. Além disso, observou-se que as espécies dos gêneros Stenocephalum, Stilpnopappus e Rolandra (Grupo 1) estão relacionadas às espécies do gênero Vernonanthura (Grupo 2), enquanto que as espécies dos gêneros Chrysolaena, Cyrtocymura e Echinocoryne (Grupo 3) estão relacionadas às espécies dos gêneros Lessingianthus e Lepidaploa (Grupo 4), indicando que as subtribos Vernoniinae e Lepidaploinae são parafiléticas. Diversos metabólitos foram identificados nas espécies analisadas, destacando-se os ácidos clorogênicos, os flavonoides e as lactonas sesquiterpênicas. Através da análise por OPLS-DA foi possível determinar os metabólitos responsáveis pela separação entre os grupos obtidos na análise por HCA. As espécies do Grupo 1 foram caracterizadas pela ausência de ácido 3-O-cafeoilquínico e 3,5-di-O-cafeoilquínico; o Grupo 2 foi caracterizado pela ausência de quercetina e presença de kaempherol 3-O-rutinosídeo; o Grupo 3 foi o único grupo no qual não foi identificado o flavonoide 7,3?,5?-trihidroxi- 4?-metoxi-3-O-glicosilflavona e as espécies do Grupo 4 caracterizaram-se por apresentarem baixa prevalência de flavonas. Dessa maneira, as análises metabolômicas em conjunto com análises estatísticas multivariadas auxiliaram no esclarecimento da classificação taxonômica das espécies do gênero Vernonia s.l. e permitiram a identificação de potenciais marcadores quimiotaxonômicos / Vernonia sensu lato is one of the largest and more complex genus of the tribe Vernonineae. The tribe belongs to Asteraceae, one of the largest families of flowering plants. Vernonineae is distributed widely in tropical and subtropical regions of America, Africa and Asia and it is chemically characterized by the presence of sesquiterpene lactones and flavonoids (flavones and flavonols). Over the years, several taxonomic classifications have been proposed for the genus Vernonia s.l., however there has been no consensus among the researches. According to the traditional classification, the genus Vernonia s.l. comprises more than 1000 species and it is divided into sections and subsections (sensu Baker). In a recent classification, these species have been segregated into new genera, while the genus Vernonia sensu stricto was restricted to 22 species distributed mainly in North America (sensu Robinson). In this study, species belonging to the subtribes Vernoniinea, Lepidaploinae and Rolandrinae were analysed, employing UHPLC-UV(DAD)-MS(Orbitrap), followed by multivariate analyses. Data mining was performed using unsupervised (HCA and PCA) and supervised statistical analysis (OPLS-DA). The HCA showed segregation into four main groups. Comparing the HCA with the taxonomical classifications, we observed that the groups of the dendogram were in accordance with the genera created by Robinson. The species of the genera Stenocephalum, Stilpnopappus and Rolandra (Group 1) are more related with the species of the genus Vernonanthura (Group 2), while the genera Cyrtocymura, Chrysolaena and Echinocoryne (Group 3) are chemically more similar to the genera Lessingianthus and Lepidaploa (Group 4). These findings indicate that the subtribes Vernoniinae and Lepidaploinae are paraphyletic groups. Several metabolites were identified, highlighting chlorogenic acids, flavonoids and sesquiterpene lactones. ). According to OPLS-DA loading plot, it was possible to determine which variables are important for the discrimination among the groups. The species of the Group 1 were characterized by the absence of 3-O-caffeoylquinic acid and 3,5-di-O-caffeoylquinic acid. Group 2 was characterized by the absence of quercetin (flavonol with free OH) and by the presence of kaempherol 3-O-rutinoside. Group 3 was the only group that do not show the flavonoid 7,3?,5?-trihydroxy-4?- methoxy-3-O-glycosylflavone. The species of the Group 4, especially the species of the genus Lessingianthus, were characterized by the low prevalence of flavones. Therefore, untarget metabolomic approach associated with mutivariate analysis allowed the identification of potential chemotaxonomic markers, helping in the taxonomical classifications
578

Estudos de metabolismo in vitro de produtos naturais: biotransformação microbiana da piplartina / In vitro metabolism studies of natural products: microbial biotransformation of piplartine

Silva Junior, Eduardo Afonso da 25 March 2013 (has links)
A piplartina é um alcaloide natural conhecido por apresentar diversas atividades biológicas, onde se destaca a ação anticancerígena. Esse produto natural apresentou atividade seletiva frente a vários tipos de células cancerígenas, sendo assim considerado promissor para o desenvolvimento de fármacos. O conhecimento do metabolismo de produtos naturais bioativos é uma importante e necessária etapa para avaliar a eficácia e segurança dessas substâncias. Os micro-organismos são amplamente utilizados em estudos de metabolismo, uma vez que catalisam reações quimio-, régio-, e estereoespecíficas, que muitas vezes são semelhantes às catalisadas pelos seres humanos. Nesse contexto, esse trabalho teve o objetivo de estudar o metabolismo microbiano da piplartina pelos fungos endofíticos Papulaspora immersa SS13 e Penicillium crustosum VR4, de solo Mucor rouxii NRRL 1894, e de coleção comercial Cunninghamella echinulata ATCC 8688a e Beauveria bassiana ATCC 7159. Os experimentos de biotransformação foram monitorados por UPLC-DAD-MS e UPLC-DAD-MS/MS. Todos os fungos utilizados biotransformaram a piplartina, sendo que 14 substâncias majoritárias foram identificadas como produtos de biotransformação nos experimentos em pequena escala. A piplartina e seus derivados apresentaram fragmentações características em IES-EM/EM que foram explicadas utilizando cálculos computacionais. O estudo dessas fragmentações permitiu a identificação e proposição das alterações estruturais que ocorreram nos metabólitos formados. Os fungos P. crustosum VR4 e B. bassiana ATCC 7159 foram selecionados para realizar os experimentos de biotransformação em escala ampliada, pois foram capazes de formar a maior diversidade de derivados da piplartina. Cinco substâncias foram isoladas e identificadas por RMN de 1H, RMN de 13C, HMQC, HMBC, COSY e HRESIMS. Essas substâncias não tinham sido obtidas por biotransformação microbiana anteriormente, sendo que uma ainda não foi descrita na literatura. Foram identificados principalmente produtos formados a partir de reações semelhantes às do metabolismo humano de fase I, como reduções, hidroxilações e hidrólises. Dessa forma, podemos concluir que as culturas microbianas são uma ferramenta útil para estudos preliminares de metabolismo, e para obter padrões de metabólitos que podem ser formados pelo metabolismo humano. / Piplartine is a natural alkaloid recognized by its biological properties, especially the anticancer activity. This natural product showed selective activity against several cancer cells lines, thus being considered a promising hit for drug development. Studies of bioactive natural products metabolism are an important and necessary step for the evaluation of their efficacy and safety. Microorganisms have been widely employed in metabolism studies, since they may catalyze chemo-, regio- and stereospecific reactions that are similar to human metabolism. This work aimed to study the microbial metabolism of piplartine by different fungal strains: the endophytes Penicillium crustosum VR4 and Papulaspora immersa SS13, the soil strain Mucor rouxii NRRL 1894, and the commercial collection strains Cunninghamella echinulata ATCC 8688a and Beauveria bassiana ATCC 7159. Biotransformation experiments were monitored by UPLC-DAD-MS and UPLC-DADMS/ MS. All the screened fungi were able to biotransform piplartine, and 14 compounds were identified as major biotransformation products in the small scale experiments. Piplartine and its derivatives showed characteristics fragmentations on ESI-MS/MS, which were explained using computer calculations. These fragmentation studies allowed the identification and structural proposition of piplartine metabolites. The fungi P. crustosum VR4 and B. bassiana ATCC 7159 were selected to perform the large scale biotransformation experiments, since they were capable to produce a large diversity of piplartine derivatives. Five compounds were isolated and identified by 1H NMR, 13C NMR, HMQC, HMBC, COSY and HRESIMS data. The isolated products had never been previously identified by microbial biotransformation, and one of them was found to be novel in the literature. All the identified and isolated compounds have been produced by reactions similar to those that occur in phase I of human metabolism, such as reduction, hydroxylation and hydrolysis reactions. Thus, we can conclude that the microbial cultures are useful tools for preliminary metabolism studies, and to obtain chemical standards similar to those produced by human metabolism
579

Estudo farmacognóstico e farmacológico de Leonurus japonicus Houtt / Pharmacognostic and pharmacological study of Leonurus japonicus Houtt

Melo, Elisângela Severina de 11 October 2006 (has links)
L. japonicus, o popular \"rubim\", pertence à família Lamiaceae. O presente trabalho tem como objetivo contribuir e complementar trabalho realizado anteriormente sobre a mesma espécie, em relação à caracterização farmacobotânica, aspectos químicos e farmacológicos, incluindo atividade antiúlcera, antioxidante e antimicrobiana. A droga, constituída de folhas e caule, foi caracterizada macro e microscopicamente. O extrato hidroetanólico 70% liofilizado (EHEL), preparado com as partes aéreas, obtido através de percolação, apresentou na triagem fitoquímica presença de flavonóides, taninos, saponinas e 0,06% de óleos essenciais. Os taninos presentes na droga vegetal e no extrato foram quantificados e os teores foram respectivamente de 0,06% e de 0,35%. O teor de flavonóides na droga vegetal foi de 0,76% e no EHEL, de 2,3%. O extrato foi fracionado por solventes de polaridades diferentes como clorofórmio, acetato de etila, etanol 50% e etanol. Foi determinado o perfil cromatográfico para o extrato e frações. O extrato apresentou atividade antiúlcera extremamente significativa, no modelo de indução por etanol acidificado, administrado na dose de 400 mg/kg, por via oral, reduzindo índice de Lesão, Área Total de Lesão e Área Relativa de Lesão, sendo mais evidente no próprio extrato e nas frações clorofórmica e acetato e etila, comparativamente ao controle. Não houve inibição de crescimento de Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Campylobacter coli em uma concentração de até 2.000 µg/mL, verificado através da determinação da concentração mínima inibitória pelo método de difusão em placa. O extrato não apresentou resultado significativo em relação a atividade antioxidante testada através do método que reduz o radical 2,2\'-difenil-1-picrilhidrazil (DPPH), e após o equilíbrio da reação, permite calcular a quantidade de antioxidante gasta para reduzir 50% do DPPH. / L. japonicus, popularly known as \"rubim\", belongs to the Lamiaceae family. The objective of the present study is to contribute and complement previous investigations on the same species, in relation to pharmacobotanical characterization, chemical and pharmacological aspects, including antiulcer, antioxidant e antibiotic activities. The drug, formed of leaves and stalk, was macro e microscopically qualified. Flavonoids, tannins, saponins and 0.06% of essential oils are present in the lyophilized 70% hydroalcoholic extract (HE), obtained through percolation. Tannins are present at 0,06% in the vegetable drug and at 0,35% in the extract. The content of flavonoids in the drug was at 0,76% and in the extract (HE), at 2,3%. The extract was fractioned by solvents of different polarities as chloroform, ethyl acetate, absolute ethanol and 50% ethanol. The chromatographic profile of the extract and fractions was determined. The extract, orally administered at the dose of 400 mg/kg, presented extremely significant antiulcer activity in the acidified ethanol induction model, by reduction of the Index of Lesion, Total Area of Lesion and Relative Area of Lesion. The values of the extract and of chloroformic and ethyl acetate fractions were most evident, in relation to control. There was no inhibition of growth of Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Campylobacter coli at a concentration up to 2.000 µg/mL, verified through the the minimum inhibitory concentration by the plate diffusion method. The extract didn\'t present significant result in relation to antioxidant activity tested through the method that reduces the radical 2,2\'-Diphenyl-1-picrylhydrazyl (DPPH), and after the balance of the reaction, it allows to calculate the amount of antioxidant necessary to reduce 50% of DPPH.
580

Potencial metabólico de fungos endofíticos de plantas do gênero Anthurium da Ilha de Alcatrazes / Metabolic potential of endophytic fungi of plants of the genus Anthurium from Alcatrazes Island

Sartori, Sergio Birello 07 October 2016 (has links)
Fungos endofíticos estão presentes em plantas de diversos ambientes e produzem compostos com amplas propriedades químicas e aplicações, tanto na área médico-farmacológica quanto na agronômica. Entretanto, ainda há muito a ser investigado sobre seu potencial biotecnológico, principalmente em locais pouco explorados. As ilhas apresentam um ambiente particular e altamente vulnerável, tornando-as locais promissores na busca de organismos pouco comuns ou ainda endêmicos. Sendo assim, neste trabalho foi realizado o isolamento e estudo químico e biológico de fungos endofíticos isolados de 2 espécies plantas do gênero Anthurium da Ilha de Alcatrazes-SP. Para isto, fragmentos foliares das plantas A. loefgrenii (HRCB 46467) e A. alctrazense (HRCB 46465 - endêmica da ilha) foram inoculados em 10 meios de cultivo com diferentes composições, resultando no isolamento de 106 fungos endofíticos. Por meio de análises químicas por MALDI-TOF-MS e ensaio biológico contra fitopatógenos, foram selecionados 3 fungos para estudo. Estes foram identificados por técnicas morfológicas e moleculares como sendo Penicillium citrinum (P2MSF2F3), Penicillium simplicissimum (P210-4F2) e Aureobasidium melanogenum (P7AF2F3). No estudo dos metabólitos secundários de P. citrinum foi isolado o composto citrinina, o qual apresentou atividade inibitória do crescimento micelial dos fitopatógenos Colletotrichum gloeosporioides (MIC= 125 μg mL-1), Colletotrichum lindemuthianum (MIC= 0,48 μg mL-1), Phomopsis sojae (MIC= 250 μg mL-1) e Fusarium oxysporum f. sp. phaseoli (MIC= 125 μg mL-1). Outras frações obtidas do meio metabólico de P. citrinum (fração F3a3 e citrinina) apresentaram atividade inibitória (100% de inibição) à formas promastigotas de Leishmania infantum. No estudo dos metabólitos secundários de P. simplicissimum foi obtida a fração F2b, ativa contra L. infantum (100% de inibição), da qual foram isolados os compostos andrastina A e penicisoquinolina, sendo o primeiro relato de sua produção por esta espécie, além de outros 5 compostos ainda não identificados. No estudo dos metabólitos secundários de A. melanogenum foi isolado o composto metil-orselinato, relatado pela primeira vez para este fungo. Do mesmo fungo foi obtida a fração F1d2l ativa contra L. infantum (100% inibição), da qual foram isolados 2 compostos ainda não identificados. Este é o primeiro relato de fungos isolados de antúrios da ilha de Alcatrazes, bem como do estudo de seus metabólitos secundários. Este trabalho apresenta contribuição no conhecimento sobre fungos endofíticos e seu potencial metabólico, com aplicações nas áreas agronômica e médico-farmacológica. / Endophytic fungi are present in plants in various environments and produce compounds with wide chemical properties and applications, both in the medical and in agronomic field. However, much remains to be investigated about their biotechnological potential, especially in unexplored places. Islands have a particular and highly vulnerable environment, making them promising sites in search of unusual or endemic organisms. Thus, this work represents the isolation and chemical and biological study of endophytic fungi isolated from 2 species of plants of the genus Anthurium of Alcatrazes island-SP. For this, leaf fragments from plants A. loefgrenii (HRCB 46467) and A. alcatrazense (HRCB 46465 - endemic plant from the Island) were inoculated onto 10 culture media with different composition, resulting in the isolation of 106 endophytic fungi. Three strains were selected to be studied through chemical analysis by MALDI-TOF-MS and bioassay against phytopathogens. These were identified by morphological and molecular techniques as Penicillium citrinum (P2MSF2F3), Penicillium simplicissimum (P210-4F2) and Aureobasidium melanogenum (P7AF2F3). In the study of secondary metabolites of P. citrinum it was isolated the compound citrinin, which showed inibitory activity against the plant pathogens Colletotrichum gloeosporioides (MIC= 125 μg mL-1), Colletotrichum lindemuthianum (MIC= 0.48 μg mL-1), Phomopsis sojae (MIC= 250 μg mL-1) and Fusarium oxysporum f. sp. phaseoli (MIC= 125 μg mL-1). Other fraction obtained from the metabolic extract of P. citrinum (F3a3 fraction and citrinin), showed inibitory activity (100% inibition) to Leishmania infantum promastigotes. In the study of secondary metabolites of P. simplicissimum it was obtained F2b fraction, active against L. infantum (100% inhibition), which were isolated andrastin A and penicisoquinoline compounds, the first report of its production for this species, as well 5 unidentified compounds. In the study of secondary metabolites from A. melanogenum was isolated the methyl-orsellinate compound, first reported for this fungus. From the same strain was obtained F1d2l fraction, active against L. infantum (100% inhibition), from which were isolated 2 unidentified compounds. This is the first report of fungi isolated from Alcatrazes Island anthuriums and the study of their secondary metabolites. This study presents contribution to knowledge of endophytic fungi and their metabolic potential with applications in the medical and agronomic fields.

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