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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.
1

Avaliação de técnicas cromatográficas acopladas a espectrometria de massas para análise de morfolina em manga / Evaluation of chromatographic techniques coupled to mass spectrometry for morpholine analysis in mango

Souza, Patricia Regina de 15 April 2016 (has links)
A constante preocupação com o aumento do uso de agrotóxicos nas lavouras e os riscos gerados pelos resíduos destes compostos fazem com que os órgãos responsáveis pela fiscalização de alimentos no Brasil controlem a presença dessas substâncias nos produtos que chegam à mesa do consumidor. Atualmente, um dos grandes problemas na produção de alimentos é a utilização de substâncias proibidas em lavouras, muitas das quais não possuem estudos nem limites máximos de resíduos (LMR) estabelecidos, assim como a utilização de substâncias já registradas, mas em quantidades ou métodos de manejo incorretos. Ambos os casos podem resultar em sérios problemas à saúde humana. O objetivo deste estudo foi a avaliação da determinação de morfolina em amostras de manga utilizando técnicas como a Extração em Fase Sólida e a Cromatografia Gasosa acoplada à Espectrometria de Massas (SPE-GC-MS), assim como a Microextração em Sorvente Empacotado e Cromatografia Gasosa acoplada à Espectrometria de Massas (MEPS-GC-MS). Um segundo objetivo deste estudo consistiu em desenvolver, validar e avaliar uma metodologia analítica capaz de identificar quantitativamente a morfolina em amostras de manga por Cromatografia Líquida de Ultra Eficiência acoplada a Espectrometria de Massas em tandem (UHPLC-MS/MS). Para análise por GC-MS fez-se necessária a etapa de derivatização do analito, de forma que o mesmo aumentasse sua volatilidade e diminuísse a polaridade. A comparação entre as técnicas SPE e MEPS não foi possível devido ao efeito de matriz causado pela contaminação do liner e da coluna cromatográfica. Já a metodologia validada por UHPLC-MS/MS seguiu os critérios exigidos pelo Manual de Garantia da Qualidade Analítica, do Ministério da Agricultura Pecuária e Abastecimento (MAPA). O método foi aplicado em mangas de diferentes variedades obtidas no comércio local. Não foram encontrados resíduos de morfolina em nenhuma das amostras investigadas, de acordo com a metodologia proposta. Os resultados apresentados neste trabalho estabelecem metodologias eficientes, rápidas e de baixo custo na determinação de morfolina em amostras de manga. / The recurrent increasing of the use of pesticides on crops and the consequent risks due the exposure to chemical residues have urged the food regulation agencies to control the levels of these substances in products that reach consumer\'s table. A major problem nowadays for the production of food is the use of banned substances in crops and the extrapolation of the limit dosages of substances, which may result in serious problems to human health. Furthermore, many of these substances commonly used in crops still lack substantial information about the maximum residue levels (MRLs). The aim of this study was the evaluation of morpholine levels in mango samples using distinct techniques such as Solid Phase Extraction followed by Gas Chromatography coupled to Mass Spectrometry (SPE-GC-MS) and Microextraction by Packed Sorbent followed by Gas Chromatography Mass Spectrometry (MEPS-GC-MS). Another main goal of this work is the development, validation and evaluation of an analytical methodology to identify and quantitfy the presence of morpholine in mango samples, using Ultra-High Performance Liquid Chromatography coupled to tandem Mass Spectrometry (UHPLC-MS/MS). For the analysis of samples by GC-MS, it was required an initial step of derivatization of the analyte, in order to increase its volatility and reduce polarity. The comparison between SPE and MEPS techniques could not be performed due to matrix effects caused by contamination of the liner and the chromatographic column. On the other hand, the validated methodology for UHPLC-MS/MS presented herein followed all requirements proposed by the Analytical Quality Assurance Manual, accordingly to the Ministry of Agriculture, Livestock and Food Supply from Brazil. This method was applied in mango sample belonging to a wide variety of species found in the city of São Carlos, SP. Nevertheless, no significant levels of morpholine residues were found in any of the samples. In this work, we established a methodology efficient, fast and low cost for the determination of morpholine in mangos.
2

Avaliação de técnicas cromatográficas acopladas a espectrometria de massas para análise de morfolina em manga / Evaluation of chromatographic techniques coupled to mass spectrometry for morpholine analysis in mango

Patricia Regina de Souza 15 April 2016 (has links)
A constante preocupação com o aumento do uso de agrotóxicos nas lavouras e os riscos gerados pelos resíduos destes compostos fazem com que os órgãos responsáveis pela fiscalização de alimentos no Brasil controlem a presença dessas substâncias nos produtos que chegam à mesa do consumidor. Atualmente, um dos grandes problemas na produção de alimentos é a utilização de substâncias proibidas em lavouras, muitas das quais não possuem estudos nem limites máximos de resíduos (LMR) estabelecidos, assim como a utilização de substâncias já registradas, mas em quantidades ou métodos de manejo incorretos. Ambos os casos podem resultar em sérios problemas à saúde humana. O objetivo deste estudo foi a avaliação da determinação de morfolina em amostras de manga utilizando técnicas como a Extração em Fase Sólida e a Cromatografia Gasosa acoplada à Espectrometria de Massas (SPE-GC-MS), assim como a Microextração em Sorvente Empacotado e Cromatografia Gasosa acoplada à Espectrometria de Massas (MEPS-GC-MS). Um segundo objetivo deste estudo consistiu em desenvolver, validar e avaliar uma metodologia analítica capaz de identificar quantitativamente a morfolina em amostras de manga por Cromatografia Líquida de Ultra Eficiência acoplada a Espectrometria de Massas em tandem (UHPLC-MS/MS). Para análise por GC-MS fez-se necessária a etapa de derivatização do analito, de forma que o mesmo aumentasse sua volatilidade e diminuísse a polaridade. A comparação entre as técnicas SPE e MEPS não foi possível devido ao efeito de matriz causado pela contaminação do liner e da coluna cromatográfica. Já a metodologia validada por UHPLC-MS/MS seguiu os critérios exigidos pelo Manual de Garantia da Qualidade Analítica, do Ministério da Agricultura Pecuária e Abastecimento (MAPA). O método foi aplicado em mangas de diferentes variedades obtidas no comércio local. Não foram encontrados resíduos de morfolina em nenhuma das amostras investigadas, de acordo com a metodologia proposta. Os resultados apresentados neste trabalho estabelecem metodologias eficientes, rápidas e de baixo custo na determinação de morfolina em amostras de manga. / The recurrent increasing of the use of pesticides on crops and the consequent risks due the exposure to chemical residues have urged the food regulation agencies to control the levels of these substances in products that reach consumer\'s table. A major problem nowadays for the production of food is the use of banned substances in crops and the extrapolation of the limit dosages of substances, which may result in serious problems to human health. Furthermore, many of these substances commonly used in crops still lack substantial information about the maximum residue levels (MRLs). The aim of this study was the evaluation of morpholine levels in mango samples using distinct techniques such as Solid Phase Extraction followed by Gas Chromatography coupled to Mass Spectrometry (SPE-GC-MS) and Microextraction by Packed Sorbent followed by Gas Chromatography Mass Spectrometry (MEPS-GC-MS). Another main goal of this work is the development, validation and evaluation of an analytical methodology to identify and quantitfy the presence of morpholine in mango samples, using Ultra-High Performance Liquid Chromatography coupled to tandem Mass Spectrometry (UHPLC-MS/MS). For the analysis of samples by GC-MS, it was required an initial step of derivatization of the analyte, in order to increase its volatility and reduce polarity. The comparison between SPE and MEPS techniques could not be performed due to matrix effects caused by contamination of the liner and the chromatographic column. On the other hand, the validated methodology for UHPLC-MS/MS presented herein followed all requirements proposed by the Analytical Quality Assurance Manual, accordingly to the Ministry of Agriculture, Livestock and Food Supply from Brazil. This method was applied in mango sample belonging to a wide variety of species found in the city of São Carlos, SP. Nevertheless, no significant levels of morpholine residues were found in any of the samples. In this work, we established a methodology efficient, fast and low cost for the determination of morpholine in mangos.
3

Contribution à l'étude phytochimique et à la valorisation biologique du latex de Hura crepitans L. / Contribution to the phytochemical study and biological valuation of the latex of Hura crepitans L.

Trinel, Manon 16 November 2018 (has links)
Une collaboration entre les chercheurs du laboratoire Pharma-Dev et de l'Institut de Recherche en Santé Digestive a été mise en place depuis plusieurs années avec pour objectif le criblage thérapeutique de nouvelles molécules naturelles issues de la biodiversité végétale. Dans ce contexte, le travail présenté dans ce manuscrit est consacré à l'étude phytochimique du latex de Hura crepitans L. (Euphorbiaceae) et à la valorisation biologique de ses constituants sur des lignées cancéreuses colorectales humaines. La richesse en structures diterpéniques originales de la famille des Euphorbiaceae et le rôle de ces noyaux structuraux dans l'activation de Protéines Kinases C (PKC) impliquées dans la carcinogenèse colorectale, font de H. crepitans une espèce au potentiel thérapeutique important. Au cours de ce travail, une approche déréplicative par UHPLC-MS/MS a permis de mettre en évidence la présence de cérébrosides et une richesse notable en diterpènes de type daphnane chez H. crepitans. Au total, 33 daphnanes dont 25 nouvelles structures ont été détectées. Le fractionnement du latex a permis l'isolement de 7 daphnanes mono-estérifiés (D1) et de 6 dérivés di-estérifiés. L'évaluation biologique a révélé une activité cytostatique des D1 spécifique sur la lignée cancéreuse Caco-2 comparée à d'autres lignées intestinales normales ou cancéreuses. Cette activité est inhibée par les cérébrosides. Le D1 majoritaire, la huratoxine, a montré une activité cytostatique dès 1 µg/ml et comparativement plus spécifique que le 5-Fluoro-Uracile, cytotoxique utilisé comme référence. De plus, nous avons montré que les effets cytostatiques de la huratoxine et de l'ester de phorbol TPA sont corrélés à la régulation de signaux clés de la carcinogenèse colorectale, GSK3ß et AKT notamment, et à des changements morphologiques. Finalement, nous avons pu identifier une isoenzyme PKC comme cible potentielle de ces composés naturels. / A collaboration between the researchers of the laboratory Pharma-Dev and the Research institute in Digestive Health has been established since several years with as main objective the therapeutic screening of new natural molecules from the plant biodiversity. In this context, the work presented in this manuscript deals with the phytochemical study of the latex of Hura crepitans L. (Euphorbiaceae) and the biological valuation of its constituents on human colorectal cancerous cell lines. The wealth in original diterpene like structures within the family of Euphorbiaceae and the role of these structural cores in the activation of Proteins Kinases C (PKC) involved in the colorectal carcinogenesis, make of H. crepitans a species with a promising therapeutic potential. In the course of this work, a dereplicative approach by UHPLC-MS/MS allowed to highlight the presence of cerebrosides and a notable wealth in daphnane type diterpene in H. crepitans. This led to the annotation of 33 daphnanes including 25 new structures. Therefore, 7 mono-esterified daphnanes (D1) and 6 di-esterified derivatives could be isolated. The biological evaluation revealed, for D1, a specific cytostatic activity on the cancerous cell line Caco-2 when compared to other non-cancerous or cancerous intestinal cell lines. This activity is inhibited by cerebrosides. The main D1, huratoxine, is cytostatic from 1 µg/ml and was showed to be more specific than 5-Fluoro-Uracile, a cytotoxic drug used as reference. Furthermore, we demonstrated that the cytostatic effects of huratoxine and phorbol ester TPA are correlated to the regulation of key signals of the colorectal carcinogenesis, particularly GSK3ß and AKT, and in cells morphological changes. Finally, we were able to identify a PKC isoenzyme as a potential target of these natural products.
4

Vliv stresového faktoru sucha na obsah glykoalkaloidů brambor (Solanum tuberosum L.) / Effect of drought stress factor on glycoalkaloid contents in potato (Solanum tuberosum L.)

Matoušková, Vendula January 2016 (has links)
Potatoes are an important and irreplaceable crop. This kind of crop is very important not only for it is use but also for a nutrition composition. There are also a prominent source of vitamins, minerals and antioxidants. Outside substances beneficial to health and potatoes contain harmful substances. These substances are foreign or naturally occurring, which include toxic glycoalkaloids. Glycoalkaloids are secondary metabolites of plants. Glycoalkaloids in potatoes have protective function it can increase the synthesis for example in case of pest infestations, mechanical damage or in case of to much light and heat. The potatoes were found several glycoalkaloides. Main, which constitutes 95 % of their content, are alpha-chaconine and alpha-solanine. Their toxicity is inhibition of acetylcholinesterase and breaking the cell membranes. The potato tuber is their content is distributed unevenly. The quantity of glycoalkaloids is affected by manny factors as for example place, year, kind, the way how the crops are grown and storage. In Czech Republic the maximum allowed limit of glycoalkaloides in potatoes were made by legislation on 200 mg/kg fresh potato matter. In the commonly grown varieties of the amount is far below the hygienic limit. The methods for isolation of glycoalkaloids in potatoes are mainly chromatographic. The most commonly used HPLC (high performance liquid chromatography). In performed experiment was determined the content of majority glycoalkaloid alpha- chaconinu and alpha-solaninu at four different kinds -Milva, Marabel, Laura and Valfi. Drought stress has been studied for their content, assuming their accumulation in comparison with the other two variants - irrigation watering and drip irrigation. The glycoalkaloides content were messured by the UHPLC/MS/MS. The obtained results concluded that the content of glycoalkaloids is the variety dependent. Drought stress can probably increase their content. In our experiment, it positively did not. Important is the choice of kind in case if expectation a hot and dry year of growing. Kinds Milva and Marabel are very good in these conditions. In the case of general principles for cultivation, storage and cooking, the glykoalkaloids does not vision a risk for the consumer.
5

Studium množství antioxidantů v extraktech z Melissa Officinalis / Study of the amount of antioxidants in extracts from Melissa officinalis

Bartoš, Karel January 2021 (has links)
This diploma thesis deals with the determination of selected antioxidants, namely rosmarinic acid, caffeic acid, cinnamic acid and t-4-hydroxycinnamic acid in aqueous and ethanolic extracts from Melissa officinalis. The aim of the work was to find out whether the above- mentioned antioxidants were present in the extracts prepared at home. A new UHPLC method with UV and MS detection was developed to monitor the content of rosmarinic acid, caffeic acid, cinnamic acid and t-4-hydroxycinnamic acid in the extracts. A BEH C18 column (2,1 mm × 100 mm, particle size 1,7 µm) was selected for separation, the mobile phase consisted of methanol (component A) and 0.1% aqueous formic acid solution at pH 2.6 (component B), the ratio of components being changed according to the gradient program. The method was validated and repeatability, limits of detection and limits of quantification, linearity, yield and robustness were determined after optimization. Analysis of 20 aqueous and 20 ethanolic extracts was performer differing in extraction time, type of solvent and lighting conditions. Based on the comparison of retention time and MS detection, the presence of 3 of 4 selected phenolic acids was confirmed, namely rosmarinic acid, caffeic acid and cinnamic acid in ethanolic extracts. Unfortunately, the presence of...
6

Metabolômica como ferramenta na análise quimiotaxonômica do gênero Catasetum (ORCHIDACEAE) / Metabolomics as a tool for chemotaxonomic analysis of the genus Catasetum (Orchidaceae)

Bandeira, Karen Dayane de Oliveira 31 March 2017 (has links)
A família Orchidaceae é a maior família entre as monocotiledôneas e representa uma das maiores famílias de plantas floríferas com um número estimado de cerca de 30 mil espécies. A complexidade taxonômica de um dos gêneros dentro dessa família, o Catasetum, tem despertado muito interesse por parte dos cultivadores e pesquisadores em Orchidaceae, especialmente devido aos novos táxons que estão sendo descobertos no gênero. Visando aprimorar a classificação de espécies do gênero, uma ferramenta a ser utilizada é a análise dos constituintes químicos do metabolismo dessas plantas, onde fica evidenciada a necessidade de estudos utilizando métodos analíticos mais sensíveis, rápidas e seletivas, como a análise metabolômica. A obtenção da impressão digital metabólica é a obtenção detalhada dos metabólitos do organismo sob determinada condição, produzindo um cromatograma que é característico daquela planta, como uma impressão digital. Através disso, é possível determinar diferenças metabólicas em amostras, por meio de ferramentas estatísticas. Para o refinamento dos dados, é necessário o uso de softwares específicos que extraem as informações úteis para as análises. Foram analisadas 42 espécies distintas do gênero Catasetum e algumas duplicatas, totalizando 51 amostras por GC-MS e UHPLC-MS(ESI-Orbitrap). As \"impressões digitais\" metabólicas foram processadas nos softwares MetAlignTM e MSClust, e as matrizes geradas foram analisadas por análise de componentes principais (PCA), análise de cluster hierárquico (HCA) e análise discriminante ortogonal por mínimos quadrados parciais (OPLS-DA). Os métodos utilizados para as análises tanto por GC-MS quanto por UHPLC-MS resultaram em dados satisfatórios para análise metabolômica, gerando 57 substâncias voláteis identificadas a partir da fragrância das flores, sendo acetato de nerila, sabineno, ?-mirceno, ?-pineno e ?-pineno as mais frequentes. Os resultados das análises metabolômicas apresentaram proximidade com a filogenia, principalmente em níveis mais específicos. Os grupos gerados pelas análises, de modo geral, foram coerentes quanto à semelhança metabólica entre as espécies que os compõem, sugerindo a possibilidade do uso de impressões digitais metabólicas como uma boa ferramenta para análise quimiotaxonômica / The Orchidaceae family is the largest family among monocotyledons and represents one of the largest families of flowering plants with an estimated 30,000 species. The taxonomic complexity of one of the genera within this family, the Catasetum, has aroused much interest from growers and researchers in Orchidaceae, especially due to the new taxa being discovered in the genus. Aiming to improve the classification of species of the genus, a tool to be used is the analysis of the chemical constituents of the metabolism of these plants, where it is evidenced the need for studies using analytical methodologies more sensitive, fast and effective, such as the metabolomics analysis. Obtaining the metabolic fingerprint is the detailed obtaining of the metabolites of the organism under certain condition, producing a chromatogram that is characteristic of that plant, like a fingerprint. Through this, it is possible to determine metabolic differences in samples, through statistical tools. For the refinement of the data, it is necessary to use specific softwares that extract the useful information from analyzes data. The information generated can be used with different applications. A total of 51 samples were analyzed by GC-MS and UHPLC-MS (ESI-Orbitrap), 42 different species of the genus Catasetum and some duplicates. Metabolic \"fingerprints\" were processed in the MetAlignTM and MSClust softwares, and the generated matrices were analyzed by Principal Component Analysis (PCA), hierarchical cluster analysis (HCA) and partial least squares orthogonal discriminant analysis (OPLS-DA). The methods used for analysis by both GC-MS and UHPLC-MS resulted in satisfactory data for metabolomics analysis, generating 57 volatile substances identified from the flower fragrance, being neryl acetate, sabinene, ?-myrcene, ?-pinene and ?-pinene the most frequent. The results of the metabolic analyzes showed proximity to the phylogeny, mainly in more specific levels. The groups generated by the analyzes, in general, were coherent regarding the metabolic similarity between the species that compose them, suggesting the possibility of the use of metabolic fingerprints as a good tool for chemotaxonomic analysis
7

Avaliação da estabilidade dos compostos bioativos de polpas de frutas nativas submetidas ao processo de irradiação / Evaluation of the stability of bioactive compounds in native fruit pulp exposed to irradiation process

Castelucci, Ana Carolina Leme 02 July 2015 (has links)
O Brasil é um dos principais produtores de frutas, porém esta produção está pautada em frutas na maioria das vezes exóticas. Existe uma diversidade de frutas nativas brasileiras ainda desconhecidas e pouco exploradas. Tendo em vista a grande importância da Myrtaceae no que diz respeito à conservação da Mata Atlântica; o potencial econômico e nutricional da produção de polpa de frutas nativas; e considerando que o processamento de alimentos pode exercer efeitos sobre o nível de nutrientes, particularmente no que tange ao teor de compostos bioativos e sua atividade antioxidante, este trabalho teve como objetivo gerar conhecimento sobre a composição e capacidade antioxidante das polpas de frutas, com o intuito de ampliar seu consumo, potencial de comercialização e agregar valor as mesmas, bem como, avaliar o efeito da radiação gama nas propriedades bioativas, durante o período de armazenamento refrigerado das polpas e, por fim, a identificação e quantificação dos compostos fenólicos. As polpas de uvaia (Eugenia pyriformis Camb.), cambuci (Campomanesia phaea), feijoa (Acca sellowiana), grumixama (Eugenia brasiliensis) e cereja do rio grande (Eugenia involucrata), foram divididas em 5 lotes, 4 deles foram submetidos ao tratamento de irradiação (0, 2, 4, e 6 kGy) e 1 lote a pasteurização (85°C/5min.). Os resultados demonstraram que as polpas possuem quantidades expressivas de compostos com atividade antioxidante, sendo que, a polpa de uvaia destacou-se pelos teores de ácido ascórbico, que variaram de 89,99 mg.100 g-1 na pasteurizada a 64,74 mg.100 g-1 a 6 kGy, e pelos carotenoides, que variaram de 24,7 ?g.g-1 no controle a 15,94 ?g.g-1 a 4 kGy. Na feijoa destacam-se os flavonoides no controle, 10,21 mg de ác. gálico.mL-1, nas irradiadas com 2; 4 e 6 kGy, 9,75; 11,58 e 12,79 mg de ác. gálico.mL-1, respectivamente, e na pasteurizada 12,64 mg de ác. gálico.mL-1. As antocianinas foram encontradas em maiores quantidades nas polpas de grumixama (pasteurizadas, 106,01 mg eq. cianidina-3-glicosideo.L-1, irradiadas a 2, 4 e 6 kGy, 52,93; 32,36 e 48,64, respectivamente e no controle 59,75) e cereja do rio grande (pasteurizadas 136,33 mg eq. cianidina-3-glicosideo.L-1, controle 77,11 mg eq. cianidina-3-glicosideo.L-1 e nas irradiadas 74,91; 77,7 e 69,47 mg eq. cianidina-3-glicosideo.L-1, respectivamente a 2, 4 e 6 kGy). Na polpa de cambuci não foram encontrados teores de flavonoides e antocianinas e apresentaram valores relativamente baixos dos outros compostos estudados. O composto fenólico majoritariamente encontrado na polpa de uvaia foi o ácido gálico, na feijoa os ácidos elágico e quínico, no cambuci, o ácido quínico, na grumixama o ácido elágico e a quercetina e na cereja do rio grande o ácido quínico e a rutina. Apesar da radiação gama ser um eficiente método de conservação e poder ser utilizada sem prejuízo dos compostos bioativos, nas condições estudadas, as doses entre 2 e 6 kGy, não foram efetivas para evitar as perdas dos compostos bioativos de interesse, no período de armazenamento, apresentando resultados inferiores em relação à pasteurização quanto às antocianinas, compostos fenólicos totais e a atividade antioxidante, medida por ABTS e DPPH / Brazil is a major producer of exotic native fruits. There is a diversity of native fruits still unknown and slightly researched. Taking into consideration the great importance of Myrtaceae regarding the conservation of the Atlantic Forest; the economic and nutritive potential of the production of native fruit pulp; and considering that the food processing may affect the level of nutrients, particularly with regard to the bioactive compound content and its antioxidant activity, the purpose of this study is to generate knowledge on the composition and the antioxidant capability of Myrtaceae pulps. The study aims at enlarging the consumption of Myrtaceae pulps, their marketing potential and their value-added, as well as at evaluating the effect of gamma radiation on bioactive properties during the cold storage period of pulps, and finally, the identification and quantification of the phenolic compounds. The pulps of uvaia (Eugenia pyriformis Camb.), cambuci (Campomanesia phaea), feijoa (Acca sellowiana), grumixama (Eugenia brasiliensis) and cereja do rio grande (Eugenia involucrata) were divided into 5 batches, 4 of them were exposed to irradiation (0, 2, 4, e 6 kGy) and one batch pasteurization (85°C/5min.) treatments. The results showed that the pulps have an expressive quantity of compounds with antioxidant activity. Uvaia pulp stood out by the ascorbic acid contents, which decreased from 89,99 mg.100 g-1 in pasteurization to 64,74 mg.100 g-1 by 6 kGy, and by the carotenoids, which varied from 24,7 ?g.g-1 in the control sample to 15,94 ?g.g-1 by 4 kGy. Feijoa presented high levels of flavonoids in the control sample, 10,21 mg of gallic acid.mL-1, in irradiation 2; 4 and 6 kGy, 9,75; 11,58 e 12,79 mg of gallic acid.mL-1, respectively, and in pasteurization 12,64 mg of gallic acid.mL-1. The anthocyanins were found in major quantities in the grumixama pulps (in pasteurization, 106,01 mg eq. cianidina-3-glicosideo.L-1, irradiated by 2, 4 e 6 kGy, 52,93; 32,36 e 48,64, respectively and in the control sample 59,75) and cereja do rio grande (in pasteurization 136,33 mg equ. cianidina-3-glicosideo.L-1, in the control sample 77,11 mg equ. cianidina-3-glicosideo.L-1 and irradiated 74,91; 77,7 and 69,47 mg equ. cianidina-3-glicosideo.L-1, respectively by 2, 4 e 6 kGy). Flavoniods and anthocyanins were not found in cambuci pulps. Also, there were low values of the others researched compounds in cambuci pulps. The phenolic compound majorly found in the uvaia pulp was the gallic acid, in the feijoa was the ellagic and quinic acids, in cambuci was the quinic acid, in the grumixama was the ellagic acid and quercetin, and in the cereja do rio grande was the quinic acid and the rutin. Although the gamma radiation revealed to be an efficient conservation method and may be used without prejudice of bioactive compounds, based on the conditions researched, the doses between 2 and 6 kGy were not effective to prevent losses of bioactive compounds of interest in the cold storage period, presenting lower results in relation to the pasteurization treatment as anthocyanins, total of phenolic compounds and the antioxidant activity measured by ABTS and DPPH
8

Etude physico-chimique et valorisation de composés bioactifs de Parinari macrophylla Sabine (Chrysobalanaceae) / Physicochemical study and valorization of bioactive compounds of Parinari macrophylla Sabine (Chrysobalanaceae)

Balde, Mamadou 31 August 2018 (has links)
Le diabète de type 2 est souvent associé à un stress oxydant pouvant entrainer plusieurs complications métaboliques. Au Sénégal, en plus du traitement médicamenteux, les plantes médicinales restent encore très utilisées dans la prise en charge de cette pathologie. Le but de ce travail a été de contribuer à la valorisation de la biodiversité sénégalaise et plus particulièrement d’approfondir les connaissances phytochimiques de Parinari macrophylla Sabine, utilisée traditionnellement pour le traitement du diabète. Pour cela, l’activité anti-radicalaire totale et au niveau moléculaire des feuilles et écorces a été déterminée par les méthodes TEAC, ORAC et HPLC - ABTS•+ online. De plus un screening phytochimique (réactions de précipitation, CCM) a été réalisé et a permis de mettre en évidence plusieurs groupes chimiques de composés tels que des flavonoïdes, des tanins, des terpènes, des anthracènes, des saponosides, des hétérosides cardiotoniques et des alcaloïdes. Pour l’identification des composés actifs, la RMN et l’approche par réseau moléculaire (UHPLC-MS), ont permis d’identifier l’acide chlorogénique, l’hyperoside, la procyanidine B2 et d’autres procyanidines. L’étude in vitro réalisée sur un modèle cellulaire RINm5F a montré une faible activité anti-radicalaire des extraits de plante vis-à-vis d’un stress induit à l’HX-XO. Toutefois les composés identifiés dans cette étude sont connus pour leurs effets antioxydants et inhibiteurs sur les enzymes digestives responsables du métabolisme du glucose. Cela pourrait justifier l’utilisation de cette plante dans le traitement du diabète de type 2 par les tradithérapeutes Sénégalais. / Type 2 diabetes is often associated with oxidative stress that can lead to several metabolic complications. In Senegal, in addition to drug treatment, medicinal plants are still widely used in the treatment of this pathology. The aim of this work was to contribute to the enhancement of Senegalese biodiversity and more particularly to improve the phytochemical properties of Parinari macrophylla Sabine, traditionally used for the treatment of diabetes. For this, the total antiradical activity and at the molecular level of leaves and bark has been determined by the TEAC, ORAC and HPLC - ABTS-+ online methods. In addition, a phytochemical screening (precipitation reactions, CCM) was carried out and revealed several chemical groups of compounds such as flavonoids, tannins, terpenes, anthracenes, saponosides, cardiotonic heterosides and alkaloids. For the identification of active compounds, NMR and the molecular network approach (UHPLC-MS), identified chlorogenic acid, hyperoside, procyanidin B2 and other procyanidins. The in vitro study carried out on a RINm5F cellular model showed a low anti-radical activity of plant extracts against HX-XO-induced stress. However, the compounds identified in this study are known for their antioxidant and inhibitory effects on digestive enzymes responsible for glucose metabolism. This could justify the use of this plant in the treatment of type 2 diabetes by Senegalese traditional therapists.
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Determinação mutirresíduo de agrotóxicos em pimentão utilizando método QuEChERS modificado e UHPLC-MS/MS / Multirresidue determination of pesticides in sweet Pepper by modified QuEChERS method and UHPLC-MS/MS

Kemmerich, Magali 28 February 2013 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / In recent years, the indiscriminate use of pesticides and non-adoption of good agricultural practices have been evidenced by the results of analysis of pesticide residues in food, such as sweet pepper, one of Brazilian record holders with active ingredients that are banned or above the recommended limits. Thus, the present study aimed to develop and validate a rapid method for the determination of 83 pesticides in sweet pepper using modified QuEChERS method and Ultra-high Performance Liquid Chromatography coupled to tandem Mass Spectrometry (UHPLC-MS/MS). In the sample preparation extraction/partition procedures, and different sorbents for clean-up were tested, such as diatomaceous earth and polymeric sorbent. It was used the 24 factorial design for optimization of the method of extraction, which consisted of the extraction of 10.0 g sweet pepper with 10.0 mL of acetonitrile. In the partition step 1.5 g of NaCl, 4.0 g MgSO4 were added, carrying out shaking and centrifugation. It was carried out the clean-up step of 1.0 ml of extract with 40.0 mg of PSA and 150.0 mg of MgSO4, followed by shaking and centrifugation. The extract was filtered, diluted and analyzed by UHPLC-MS/MS. Most compounds showed linear range (r2 ≥ 0.99).The matrix effect was compensed by using analytical curves prepared in blank matrix-matched. The accuracy of the method was verified by testing recovery at four concentration levels, yielding values between 70.0 and 120.0% for most compounds evaluated. Values of LODm and LOQm were 3 or 7.5 μg kg-1 and 10 or 25 μg kg-1, respectively. RSD values lower than 20% ensured good precision of the method. The method was performed on 20 samples of sweet pepper, in which residues of acetamiprid, azoxystrobin, boscalid, carbendazim, chlorpyrifos ethyl, clothianidin, difenoconazole, fenpropathrin, pyraclostrobin and pyrimethanil were quantified in concentrations ranging from 10 to 294 μg kg-1. The proposed modified QuEChERS method for the determination of 81 from 83 pesticide residues in sweet pepper using UHPLC-MS/MS shown to be effective and can be applied in routine analysis. / Nos últimos anos, o uso indiscriminado de agrotóxicos e a não adoção das boas práticas agrícolas têm sido evidenciados pelos resultados de análises de resíduos de agrotóxicos em alimentos, como o pimentão, um dos recordistas brasileiros com princípios ativos proibidos ou acima dos limites recomendados. Assim, o presente trabalho teve como objetivo desenvolver e validar um método rápido para a determinação de 83 agrotóxicos em pimentão, utilizando método QuEChERS modificado e Cromatografia Líquida de Ultra Eficiência acoplada à Espectrometria de Massas em série (UHPLC-MS/MS). Na etapa de preparo de amostra testou-se procedimentos de extração/partição, além de diferentes sorventes para a etapa de limpeza, como terra diatomácea e sorvente polimérico. Utilizou-se o planejamento fatorial 24 para otimização do método de extração, o qual foi constituído da extração de 10,0 g de pimentão com 10,0 mL de acetonitrila. Na etapa de partição adicionou-se 1,5 g de NaCl e 4,0 g de MgSO4, seguindo-se agitação e centrifugação. Realizou-se a etapa de limpeza de 1,0 mL do extrato com 40,0 mg de PSA e 150,0 mg de MgSO4, seguido de agitação e centrifugação. O extrato foi filtrado, diluído e analisado por UHPLC-MS/MS. A maioria dos compostos apresentou faixa linear (r2≥ 0,99). O efeito matriz foi compensado utilizando-se curvas analíticas preparadas no extrato branco da matriz. A exatidão do método foi verificada com ensaios de recuperação em quatro níveis de concentração, obtendose valores entre 70,0 e 120,0% para a maioria dos compostos avaliados. Valores de LODm e LOQm foram de 3 ou 7,5 μg kg-1 e 10 ou 25 μg kg-1, respetivamente.Valores de RSD inferiores a 20% garantiram a boa precisão do método. A aplicação do método foi realizada em 20 amostras de pimentão, nas quais resíduos de acetamiprido, azoxistrobina, boscalida, carbendazim, clorpirifós etílico, clotianidina, difenoconazol, fempropatrina, piraclostrobina e pirimetanil foram quantificados, em concentrações que variaram de 10 a 294 μg kg-1. O método QuEChERS modificado proposto para a determinação de resíduos de 81 dos 83 agrotóxicos em pimentão utilizando UHPLC-MS/MS mostrou ser eficaz, podendo ser aplicado em análises de rotina.
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Avaliação da técnica de extração sortiva em disco rotatório (RDSE) para determinação multirresíduo de agrotóxicos em água por UHPLC-MS/MS / Evaluation of the rotating disk sorptive extraction (RDSE) technique for multirresidue determination of pesticides in water by UHPLC-MS/MS

Donato, Filipe Fagan 24 February 2017 (has links)
The use of pesticides in agriculture and urban areas has always been associated with advantages and disadvantages. As benefits, the increase of the productivity of crops and the control of vectors that cause diseases can be highlighted. However, excessive use of these substances has been causing human health damage as well as environmental degradation, especially regarding to water resources. In the present work, a method for the determination of 62 pesticides residues in surface water using rotating disk sorptive extraction (RDSE) as sample preparation and determination by ultra-high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS) was optimized and validated. Several parameters were evaluated during the development of the extraction method: time and rotational disk velocity in the extraction step, types and amounts of sorbents, sample pH, ionic strength, time and velocity of the rotating disk in the desorption step of the analytes and different desorption solvents. The best results were obtained using 50 mL of acidified sample at pH 2.0 and 2.5 g of NaCl. The velocity of rotation disk in the extraction stage was 1600 rpm in a time of 80 min. Inside the disk cavity the polymeric sorbent Oasis® HLB (20 mg) used. The desorption step of the analytes was performed with 3 mL of methanol for 60 min using a rotation velocity of 1600 rpm. The analytical curves showed linearity between 0.05 or 0.1 to 2 μg L-1, with r2 values greater than 0.99 for all compounds. The method LOQ values ranged from 0.05 to 0.1 μg L-1. The method showed suitable accuracy and precision, with recoveries between 70.1 and 119.9% and RSD ≤20% for the spiked levels at 0.05; 0.1; 0.5 and 2 μg L-1. The validated method was applied to 11 surface water samples from different river basins of the Rio Grande do Sul state. Only one sample presented no pesticide residues. The other samples presented residues of at least one of the following pesticides: atrazine, azoxystrobin, clomazone, difenoconazole, epoxiconazole, propoxur, simazine and tebuconazole. From the six hydrographic basins, all presented pesticides residues and the concentrations ranged between 0.06 and 0.35 μg L-1. Therefore, the results indicate that the proposed method is suitable for the analysis of pesticide residues in surface waters, allowing the preparation of several samples simultaneously with low material consumption. / O uso de agrotóxicos tanto na agricultura quanto na área urbana, sempre esteve associado a vantagens e desvantagens. Pode-se destacar como benefícios o aumento da produtividade das lavouras e o controle de vetores causadores de doenças. No entanto, a utilização excessiva destas substâncias vem causando malefícios à saúde humana e ao meio ambiente, principalmente no que diz respeito aos recursos hídricos. No presente trabalho, um método para a determinação de resíduos de 62 agrotóxicos em águas superficiais, utilizando extração sortiva em disco rotatório (RDSE) para o preparo de amostra e determinação por cromatografia líquida de ultra-alta eficiência acoplada à espectrometria de massas em série (UHPLC-MS/MS) foi otimizado e validado. Na otimização do método de extração foram avaliados diversos parâmetros como: diferentes tempos e velocidades de rotação do disco na etapa de extração, tipos e quantidades de sorventes, pH da amostra, força iônica, tempo e velocidade de rotação do disco na etapa de dessorção dos analitos e diferentes solventes de dessorção. Os melhores resultados foram obtidos utilizando 50 mL de amostra acidificada em pH 2 e adicionando 2,5 g de NaCl. A velocidade de rotação do disco na etapa de extração foi de 1600 rpm por um tempo de 80 min. Na cavidade do disco foi utilizado o sorvente polimérico Oasis® HLB (20 mg). A dessorção dos analitos foi realizada com 3 mL de metanol por 60 min usando uma velocidade de rotação de 1600 rpm. As curvas analíticas apresentaram linearidade entre 0,05 ou 0,1 a 2 μg L-1, com valores de r2 maiores que 0,99 para todos os compostos. O limite de quantificação do método variou entre 0,05 e 0,1 μg L-1. O método apresentou exatidão e precisão adequadas, com recuperações entre 70,1 e 119,9% e RSD ≤20% para níveis de fortificação 0,05; 0,1; 0,5 e 2,0 μg L-1. O método validado foi aplicado em 11 amostras de água superficiais de diferentes bacias hidrográficas do estado do Rio Grande do Sul. Apenas uma amostra não apresentou resíduos de agrotóxicos. As demais apresentaram resíduos de pelo menos um dos seguintes agrotóxicos: atrazina, azoxistrobina, clomazona, difenoconazol, epoxziconazol, propoxur, simazina e tebuconazol. Das seis bacias hidrográficas amostradas todas apresentaram resíduos de agrotóxicos e as concentrações variaram entre 0,06 e 0,35 μg L-1. Os resultados indicam que o método proposto é adequado para análise de resíduos de agrotóxicos em águas superficiais, permitindo o preparo de várias amostras simultaneamente com baixo consumo de material.

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