Submitted by LUNA MARES LOPES DE OLIVEIRA (DINTER) null (lunamares@saolucas.edu.br) on 2017-01-27T02:26:31Z No. of bitstreams: 1 CAPITULO TESE - LUNA MARES LOPES DE OLIVEIRA.pdf: 792305 bytes, checksum: 7e19ae8eb4ac1ad2447d7290d4746ef9 (MD5) / Approved for entry into archive by LUIZA DE MENEZES ROMANETTO (luizamenezes@reitoria.unesp.br) on 2017-01-31T13:11:06Z (GMT) No. of bitstreams: 1 oliveira_lml_dr_araca.pdf: 792305 bytes, checksum: 7e19ae8eb4ac1ad2447d7290d4746ef9 (MD5) / Made available in DSpace on 2017-01-31T13:11:06Z (GMT). No. of bitstreams: 1 oliveira_lml_dr_araca.pdf: 792305 bytes, checksum: 7e19ae8eb4ac1ad2447d7290d4746ef9 (MD5) Previous issue date: 2016-01-19 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / As propriedades antimicrobianas da romã são atribuídas aos compostos fenólicos, mais especificamente aos taninos hidrolisáveis (THs) galotaninos (ácido gálico) e elagitaninos (ácido elágico), substâncias naturais de defesa da planta. Os objetivos deste estudo foram avaliar os níveis de ácido elágico e fenóis totais, rendimento dos métodos de extração e o potencial inibitório sobre Candida albicans de extratos de partes da Punica granatum. Amostras em triplicata de cascas, sementes e folhas desidratadas, trituradas, pulverizadas, foram submetidas a dois métodos de extração: soxhlet tendo como solventes etanol e metanol e percolação tendo como solvente o etanol. Após a obtenção dos extratos, foram determinados os teores de ácido elágico por cromatografia liquida de alta eficiência e fenóis totais expressos em ácido gálico pelo método espectrofotométrico. A atividade antifúngica dos extratos foi avaliada pelo método de difusão em disco, seguindo-se as normas do National Committee for Clinical and Laboratory Standards (NCCLS document M2-A8, 2003a.). As maiores concentrações de fenóis totais e de ácido elágico foram encontradas nas folhas e na casca da romã. Verificou-se maior eficiência de rendimento por meio da percolação. Os resultados de difusão em disco revelaram maior sensibilidade da cepa de C. albicans aos extratos etanólicos da casca por ambos os métodos de extração. O método percolação alcoólica a 70% e 25ºC e a casca da romã apresentaram a maior eficiência de extração e de atividade anti-fúngica contra uma cepa clínica de C. albicans. / The antimicrobial properties of pomegranate are attributed to the phenolic compounds, more specifically the hydrolyzable tannins (THs) galotaninos (gallic acid) and elagitaninos (ellagic acid), natural plant defense substances. The objectives of this study were to evaluate the levels of ellagic acid and total phenols, yield of the extraction methods and the inhibitory potential against Candida albicans of extracts from parts of Punica granatum. Samples of dried, peels, seeds and leaves were used in triplicates and the extracts were obtained by Soxhlet system and percolation using respectively ethanol, methanol and ethanol solvents. After obtaining the extracts, the ellagic acid contents were determined by high performance liquid chromatography (HPLC) and total phenols expressed in gallic acid by the spectrophotometric method. The antimicrobial activity was evaluated by the disc diffusion method, following the standards of the National Committee for Clinical and Laboratory Standards (NCCLS document M2-A8, 2003a.). The highest concentrations of THs were found in leaves and pomegranate peel. Greater yield efficiency was verified by percolation. The results of diffusion on disc revealed higher sensitivity of the C. albicans strain to the ethanolic extracts of peels by both methods of extraction, presenting inhibition halos of approximately 10 mm. The alcoholic percolation method at 70% and 25ºC and the pomegranate peel showed the highest extraction efficiency and antifungal activity against a clinical strain of C. albicans. / FAPESP: 2014/08643-2 / CAPES: 88881.030445/2013-1

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Les polyphénols et les phénols sont des molécules organiques largement présentes dans le règne végétal et souvent évaluées pour leur potentiel pharmacologique. Ces travaux de thèse concernent la synthèse totale de gallotannins, une classe importante de polyphénols, et l’hémisynthèse de la norbergénine, un C-arylglucoside naturel. Les gallotannins font partie des tannins hydrolysables dont la biosynthèse conduit à des structures chimiques caractérisées par la présence, sur un cœur glucopyranose, de plusieurs unités galloyle liées les unes aux autres par des liaisons méta-depside. Aucune synthèse chimique de ces composés n’ayant été décrite à ce jour, nous avons réalisé la synthèse totale de gallotannins naturels et de leurs anomères non naturels porteurs de motifs di- ou tri-galloyle depside. Ces travaux ont également permis d’étudier l’équilibre méta-para de ces motifs en solution. Quant à l’hémisynthèse de la norbergénine, elle a été réalisée avec succès en une seule étape à partir de la bergénine, un C-arylglucoside commercial, par réaction de O-déméthylation oxydante au SIBX (version stabilisée commerciale du iodane_λ5 IBX). Cette réaction chimiosélective a également été appliquée à des 2-méthoxyphénols et a notamment permis l’obtention de l’hydroxytyrosol à partir de l’alcool homovanillique. / Polyphenols and phenols are organic molecules widely found in the plant kingdom and very often evaluated for their pharmacological potential. This thesis work describes the total synthesis of gallotannins, an important class of polyphenols, and the hemisynthesis of norbergenin, a natural C-arylglucoside. The gallotannins belong to the hydrolysable tannins whose biosynthesis leads to chemical structures characterized by the presence, on a glucopyranose core, of several galloyl units linked ones to the others by meta-depside bonds. No chemical synthesis of these compounds have been reported to date, so we completed the total synthesis of several naturally occurring meta-depsidic gallotannins and their non natural anomers that contain di- or tri-galloyl motifs. This work also allowed the study of the meta-para equilibrium of these motifs in solution. For the norbergenin hemisynthesis, it was successfully achieved in a one step reaction from bergenin, a commercial C-arylglucoside, by a SIBX-mediated oxidative O-demethylation (SIBX = commercially available stabilized version of the λ5 _iodane IBX). This chemoselective reaction was also applied to 2-methoxyphenols and notably allowed the hemisynthesis of hydroxytyrosol from homovanillyl alcohol.

Thesis (M.S.)--Miami University, Dept. of Chemistry and Biochemistry, 2008. / Title from first page of PDF document. Includes bibliographical references.