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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

Estudo químico e das atividades citotóxica, antioxidante e antifúngica de Prunus myrtifolia L. (Urban.) (ROSACEAE) /

Santos, Luciana de Ávila. January 2005 (has links)
Orientador: Dulce Helena Siqueira Silva / Resumo: O presente trabalho descreve o estudo químico das folhas e galhos de Prunus myrtifolia (L.) Urban (Rosaceae), exemplar coletado na Fazenda Campininha em São Paulo, SP. A química do gênero Prunus é determinada pela ocorrência de glicosídeos cianogênicos , terpenóides, flavonóides e outras substâncias fenólicas. Os extratos obtidos a partir de folhas e galhos de P. myrtifolia foram fracionados através de técnicas cromatográficas diversas que forneceram 31 substâncias, sendo 3 consideradas inéditas. Suas estruturas foram determinadas através de dados espectrométricos (RMN, EM, UV, entre outros), bem como através da utilização de técnicas hifenadas tais como CLAE-UV e CLAE-EM. O fracionamento cromatográfico guiado por testes químicos demonstrou o potencial de atividade antioxidante de flavonóides e arilpropanóides isolados de folhas e galhos de P. myrtifolia. A mistura de esteróides estigmasterol e sitosterol apresentou atividade antifúngica moderada frente a fungos fitopatógenos do gênero Cladosporium enquanto que os glicosídeos cianogênicos prunasina e durrina, além do ácido prunasínico apresentaram atividade antifúngica contra Cândida krusei e C. Albicans. A atividade citotóxica para Sacharomyces cerevisea apresentada pelos extratos brutos não foi mais observada após os procedimentos de fracionamento cromatográfico. Entretanto, a mistura de triterpenos pentacíclicos triidroxilados obtida a partir do extrato etanólico de galhos, apresentou atividade antitumoral para células de câncer de cólon, de mama e do sistema nervoso central humano. Os resultados obtidos com esse estudo químico corroboram dados da literatura sobre Prunus e Rosaceae e poderão contribuir com estudos de quimiossistemática. / Abstract: This work reports the results from chemical study of leaves and branches of Prunus myrtifolia (L.) Urban. (Rosaceae), collected at Fazenda Campininha, São Paulo. The chemistry of genus Prunus is determined by occurrence of cyanogenic glicosides, terpenoids, flavonoids and other phenolic compounds. Ethanolic extracts obtained from leaves and branches of Prunus myrtifolia were fractionated through chromatographic methods that led to the isolation of 28 compounds wich were previously descibed and 3 additional new compounds. Their structures were determined by spectrscopic data (NMR, MS, UV, etc), and also by the use of hyphenated technics (HPLC_UV and HPLC-MS). The fractionation guided by chemical and biological assays demonstrated the atioxidant activity of 6 flavonoids, arilpropanoid derivatives and other isolates from leaves and branches of P. myrtifolia. The mixture of steroids stigmasterol and sitosterol obtained showed moderate activity against phytopatogenic fungus of genus Cladosporium and the cyanogenic glycosides prunasin and dhurrin, and prunasinic acid showed antifungal activity against human Candida pathogens. The cytotoxic activity against Sacharomyces cereviseae presented for crude ethanol extracts were not observed anymore after the chromatograpic frationation procedures, although the trihydroxylated triterpenoids obtained from branches ethanol extract inhibited growth of colon, breast and CNS human cancer cells. Additionally, the results obtained with this work corroborate chemical data about genus Prunus and Rosaceae and therefore contribute with chemosystematic studies. / Doutor
2

Estudo químico e das atividades citotóxica, antioxidante e antifúngica de Prunus myrtifolia L. (Urban.) (ROSACEAE)

Santos, Luciana de Ávila [UNESP] January 2005 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:35:09Z (GMT). No. of bitstreams: 0 Previous issue date: 2005Bitstream added on 2014-06-13T19:05:25Z : No. of bitstreams: 1 santos_la_dr_araiq.pdf: 1408996 bytes, checksum: 5871577900c69d41b11bdee03b41554a (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / O presente trabalho descreve o estudo químico das folhas e galhos de Prunus myrtifolia (L.) Urban (Rosaceae), exemplar coletado na Fazenda Campininha em São Paulo, SP. A química do gênero Prunus é determinada pela ocorrência de glicosídeos cianogênicos , terpenóides, flavonóides e outras substâncias fenólicas. Os extratos obtidos a partir de folhas e galhos de P. myrtifolia foram fracionados através de técnicas cromatográficas diversas que forneceram 31 substâncias, sendo 3 consideradas inéditas. Suas estruturas foram determinadas através de dados espectrométricos (RMN, EM, UV, entre outros), bem como através da utilização de técnicas hifenadas tais como CLAE-UV e CLAE-EM. O fracionamento cromatográfico guiado por testes químicos demonstrou o potencial de atividade antioxidante de flavonóides e arilpropanóides isolados de folhas e galhos de P. myrtifolia. A mistura de esteróides estigmasterol e sitosterol apresentou atividade antifúngica moderada frente a fungos fitopatógenos do gênero Cladosporium enquanto que os glicosídeos cianogênicos prunasina e durrina, além do ácido prunasínico apresentaram atividade antifúngica contra Cândida krusei e C. Albicans. A atividade citotóxica para Sacharomyces cerevisea apresentada pelos extratos brutos não foi mais observada após os procedimentos de fracionamento cromatográfico. Entretanto, a mistura de triterpenos pentacíclicos triidroxilados obtida a partir do extrato etanólico de galhos, apresentou atividade antitumoral para células de câncer de cólon, de mama e do sistema nervoso central humano. Os resultados obtidos com esse estudo químico corroboram dados da literatura sobre Prunus e Rosaceae e poderão contribuir com estudos de quimiossistemática. / This work reports the results from chemical study of leaves and branches of Prunus myrtifolia (L.) Urban. (Rosaceae), collected at Fazenda Campininha, São Paulo. The chemistry of genus Prunus is determined by occurrence of cyanogenic glicosides, terpenoids, flavonoids and other phenolic compounds. Ethanolic extracts obtained from leaves and branches of Prunus myrtifolia were fractionated through chromatographic methods that led to the isolation of 28 compounds wich were previously descibed and 3 additional new compounds. Their structures were determined by spectrscopic data (NMR, MS, UV, etc), and also by the use of hyphenated technics (HPLC_UV and HPLC-MS). The fractionation guided by chemical and biological assays demonstrated the atioxidant activity of 6 flavonoids, arilpropanoid derivatives and other isolates from leaves and branches of P. myrtifolia. The mixture of steroids stigmasterol and sitosterol obtained showed moderate activity against phytopatogenic fungus of genus Cladosporium and the cyanogenic glycosides prunasin and dhurrin, and prunasinic acid showed antifungal activity against human Candida pathogens. The cytotoxic activity against Sacharomyces cereviseae presented for crude ethanol extracts were not observed anymore after the chromatograpic frationation procedures, although the trihydroxylated triterpenoids obtained from branches ethanol extract inhibited growth of colon, breast and CNS human cancer cells. Additionally, the results obtained with this work corroborate chemical data about genus Prunus and Rosaceae and therefore contribute with chemosystematic studies.
3

Herbivory by leaf-miners on Florida scrub oaks

Cornelissen, Tatiana 01 June 2006 (has links)
This study investigated effects of plant quality and natural enemies on the abundance and survivorship of several leaf miner species on Florida scrub oaks over several ecological scales. Three oak species (Quercus laevis, Q. geminata, and Q. myrtifolia) and four leafminer species (Acrocercops albinatella, Brachys tesselatus, Stilbosis quadripustulatus, and Cameraria sp. nova) were the main focus of five separate studies, addressing effects of bottom-up and top-down factors at regional, local, and individual scales. At the regional scale, it was observed that Cameraria sp. nova was aggregated into sites, and sites closer to each other exhibited similar densities of mines than sites farther apart. None of the bottom-up and top-down factors studied were spatially structured, but did influence the variation in Cameraria abundance over the range of the host plant Q. myrtifolia. At the local scale, all leaf miners studied were aggregated between and within plants, and variation in bottom-up factors among individual plants explained variation in abundance for some of the leaf miners studied. Intra-specific competition was identified as an important factor influencing mine survivorship, but inter-specific competition among leaf miners and gall-formers did not shape the community structure of oak herbivores. Experimental manipulation of bottom-up and top-down factors via fertilization and natural enemy removal showed that bottom-up effects were important determinants of leaf miner abundance, as fertilized plants supported 2 to 5-fold more herbivores than control plants. The removal of natural enemies, on the other hand, did not significantly impact the abundance and/or the survivorship of leaf miners and other guilds studied. At individual scales, it was demonstrated that two leaf miner species responded to random variations in leaf morphology, by increasing in abundance in individual host plants with more asymmetric leaves and/or higher levels of fluctuating as ymmetry. These results offered support for the plant stress hypothesis and differences in host plant quality were again partially responsible for the results found.
4

Compostos fenólicos e terpenos de Myrcia hiemalis e Myrcia myrtifolia (Myrtaceae)

Silva, Paulo Daniel January 2012 (has links)
203 f. / Submitted by Ana Hilda Fonseca (anahilda@ufba.br) on 2013-09-19T13:05:20Z No. of bitstreams: 1 UFBA - IQ - Tese - Paulo Daniel Silva.pdf: 13955578 bytes, checksum: 5f9c22ad7cc2b63b83b624f9648290cf (MD5) / Approved for entry into archive by Ana Hilda Fonseca(anahilda@ufba.br) on 2013-09-19T13:08:20Z (GMT) No. of bitstreams: 1 UFBA - IQ - Tese - Paulo Daniel Silva.pdf: 13955578 bytes, checksum: 5f9c22ad7cc2b63b83b624f9648290cf (MD5) / Made available in DSpace on 2013-09-19T13:08:20Z (GMT). No. of bitstreams: 1 UFBA - IQ - Tese - Paulo Daniel Silva.pdf: 13955578 bytes, checksum: 5f9c22ad7cc2b63b83b624f9648290cf (MD5) Previous issue date: 2012 / CNPq, FAPESB, FINEP e CAPES / Neste trabalho é descrita a investigação dos constituintes químicos não-voláteis das fases hexânica e diclorometânica obtidas das folhas de Myrcia hiemalis e da fase diclorometânica obtida das folhas de Myrcia myrtifolia. O fracionamento da fase diclorometânica de M. hiemalis resultou no isolamento de dez compostos: 7-hidróxi-6,8- dimetil-5-metóxi-isoflavona (1-h), 5-hidróxi-6,8-dimetil-7-metoxiflavanona (2-h), 6,8-dimetil- 5,7-dimetoxiflavanona (3-h), 2,7-di-hidróxi-6,8-dimetil-5-metoxiflavanona (4-h), 2’,4’-di- hidróxi-3’,5’-dimetil-4,6’-dimetoxichalcona (5-h), 2’-hidróxi-3’,5’-dimetil-4’,6’- dimetoxichalcona (6-h), 2’,6’-di-hidróxi-3’,5’-dimetil-4’-metoxichalcona (7-h), eudesm-4(15)- eno-7,11-diol (8-h), 2,3,21-tri-hidroxitaraxastan-28,20-olídeo (9-h) e ácido cinâmico (10-h). Da fase hexânica de M. hiemalis foram isoladas duas substâncias, -tocoferol (11- h) e acetato de geranilgeranila (12-h), enquanto que da fase diclorometânica de M. myrtifolia foram isoladas dez substâncias, quercetina (13-m), 2’-hidróxi-2,3’-dimetil-4’,6’- dimetoxipropiofenona (14-m), 2’-hidróxi-3’-metil-4’,6’-dimetoxibutirofenona (15-m), ácido betulínico (16-m), ácido betulônico (17-m), betulinaldeído (18-m), betulona (19-m), ácido oleanólico (20-m), ácido ursólico (21-m) e estigmasterol (22-m). Não foram encontrados relatos na literatura sobre o isolamento dos compostos 5-h, 7-h e 9-h. Os constituintes químicos das fases foram isolados e purificados por sucessivas colunas cromatográficas e cromatografia em camada delgada preparativa, bem como, foram utilizadas técnicas de filtração e recristalização. As estruturas das substâncias foram determinadas através das análises de diversas técnicas de RMN de 1H e 13C. / Salvador

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