Preparação e caracterização de casearinas de Casearia sylvestris como padrão fitoquímico
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Data
2010-03-05
Autores
Passareli, Fernando [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Tendo em vista o pequeno acervo de padrões de referência disponíveis para uso no controle de qualidade de fitoterápicos preparados a partir de espécies nativas brasileiras, este trabalho tem como objetivos preparar e caracterizar padrões de alta pureza de casearinas a partir de Casearia sylvestris, uma planta nativa da flora brasileira, que há muito tempo vem sendo usada pela população. A estratégia utilizada para o isolamento das casearinas consistiu no fracionamento do extrato etanólico das folhas por extração em fase sólida utilizando sílica e carvão ativo, cromatografia em coluna em fase normal, além de desenvolvimento de método em CLAE preparativo em fase reversa no modo isocrático e reciclante. Para as análises por CLAE preparativo no modo isocrático, inicialmente, alguns parâmetros como resolução, carga e volume de injeção foram otimizados em coluna analítica e posteriormente foi feita a transferência de escala para coluna preparativa utilizando fator de escalonamento de 21,2. A transferência foi adequada, resultando no isolamento de 10,5 mg da casearina J, 30,0 mg da casearina X e 3,0 mg da casearina Z. Em modo reciclante, foram isolados 60,0 mg da caseargrewiina F. As análises de pureza dessas substâncias foram feitas através de CLAE- DAD, calculando-se primeiramente a pureza de pico, que foi de 100% para as três casearinas analisadas e, posteriormente, a pureza cromatográfica, pelo método de normalização de área, sendo de 85,5, 97,2, e 98,6% para as casearinas J, X e caseargrewiina F, respectivamente. As análises por CLAE-DAD-EM foram importantes para confirmar o resultado de pureza de pico, assim como para obter os dados de massas dos contaminantes presentes nessas amostras. O grau de pureza por DSC não pôde ser obtido, devido à ausência do pico referente à fusão das casearinas, inferindo que as substâncias...
Taking into account the few library of reference standards available for the use in quality control of phytotherapic agents from Brazilian native species, the aim of this work was to prepare and characterize high purity standards of casearins from Casearia sylvestris, a native plant of the Brazilian flora that has been used traditionally by population for a long time as remedy. The strategy to isolate the casearins was to fraction at the ethanolic extract from leaves by solid phase extraction using silica and active charcoal, column chromatography (normal phase) and, additionally, the method development in preparative HPLC (reverse phase) using isocratic e recycling mode. For the analyses by preparative HPLC using isocratic mode, firstly of all some parameters like resolution, amount of sample and volume injection were optimized in analytical column and then the scale-up to preparative column was carried out using a scale factor of 21.2. The scale-up was appropriate, leading to the isolation of 10.5 mg of the casearin J, 30.0 mg of the casearin X and 3.0 mg of the casearin Z. In recycling mode, 60.0 mg of the caseargrewiin F were isolated. The purity analyses of these substances were carried out by HPLC-DAD, firstly measuring the peak purity, wich was 100.0% for the three analyzed casearins, and then, the chromatographic purity, by the area normalization method, wich was 85.5, 97.2 and 98.6% for the casearins J, X and caseargrewiin F, respectively. The HPLC-DAD-MS analyses were important to confirm the peak purity results as well as to obtain the mass data of contaminants wich are usually present in these samples. The measurement of the purity degree by DSC method was not possible due to the absence of fusion peak, thus it suggests an amorphous state for these substances. From the TG/DTG/DTA curves, it was possible to suggest the absence of volatile... ((Complete abstract click electronic access below)
Taking into account the few library of reference standards available for the use in quality control of phytotherapic agents from Brazilian native species, the aim of this work was to prepare and characterize high purity standards of casearins from Casearia sylvestris, a native plant of the Brazilian flora that has been used traditionally by population for a long time as remedy. The strategy to isolate the casearins was to fraction at the ethanolic extract from leaves by solid phase extraction using silica and active charcoal, column chromatography (normal phase) and, additionally, the method development in preparative HPLC (reverse phase) using isocratic e recycling mode. For the analyses by preparative HPLC using isocratic mode, firstly of all some parameters like resolution, amount of sample and volume injection were optimized in analytical column and then the scale-up to preparative column was carried out using a scale factor of 21.2. The scale-up was appropriate, leading to the isolation of 10.5 mg of the casearin J, 30.0 mg of the casearin X and 3.0 mg of the casearin Z. In recycling mode, 60.0 mg of the caseargrewiin F were isolated. The purity analyses of these substances were carried out by HPLC-DAD, firstly measuring the peak purity, wich was 100.0% for the three analyzed casearins, and then, the chromatographic purity, by the area normalization method, wich was 85.5, 97.2 and 98.6% for the casearins J, X and caseargrewiin F, respectively. The HPLC-DAD-MS analyses were important to confirm the peak purity results as well as to obtain the mass data of contaminants wich are usually present in these samples. The measurement of the purity degree by DSC method was not possible due to the absence of fusion peak, thus it suggests an amorphous state for these substances. From the TG/DTG/DTA curves, it was possible to suggest the absence of volatile... ((Complete abstract click electronic access below)
Descrição
Palavras-chave
Produtos naturais, Padrão de referência, Casearia sylvestris, Diterpenos clerodânicos, Natural products, Standard reference, Casearia sylvestris, Clerodane diterpenes
Como citar
PASSARELI, Fernando. Preparação e caracterização de casearinas de Casearia sylvestris como padrão fitoquímico. 2010. 183 f. Dissertação (mestrado) - Universidade Estadual Paulista, Instituto de Química, 2010.