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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

ContribuiÃÃo ao conhecimento quÃmico de Croton pedicellatus Kunth / Contribution to the knowledge of chemical Croton pedicellatus Kunth

Elton Luz Lopes 10 September 2012 (has links)
Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / O presente trabalho descreve o primeiro estudo quÃmico das folhas de Croton pedicellatus Kunth.(Euphorbiaceae), um arbusto, nativo da AmÃrica do Sul, popularmente conhecido como velame, nome dado a vÃrias espÃcies de Croton. O extrato etanÃlico das folhas foi submetido a procedimentos clÃssicos de cromatografia, incluindo Cromatografia LÃquida de Alta EficiÃncia (CLAE), resultando no isolamento, de 15 metabÃlitos secundÃrios: dois sesquiterpenos conhecidos como blumenol A e roseosÃdeo; cinco diterpenos clerodanos furÃnicos: 12,20:15,16-diepoxi-3-hidroxi-7,20-dioxocleroda-13(16),14-dien-18,2-olÃdeo; 12,20:15,16-diepoxi-2,8-dihidroxi-3-acetoxi-7,20-dioxocleroda-13(16),14-dien-18-oato de metila; 12,20:15, 16-diepoxi-2-hidroxi-3-acetoxi-7,20-dioxocleroda-13(16),14-dien-18-oato de metila; 12,20:15,16-diepoxi-3,8-dihidroxi-2-acetoxi-7,20-dioxocleroda-13(16),14-dien-18-oato de metila e 12,20:15,16-diepoxi-3-hidroxi-2-acetoxi-7,20-dioxocleroda-13(16), 14-dien-18-oato de metila; seis flavonoides: alpinumisoflavona; canferol; 3-O-glicopiranosilquercetina; 6ââ-O-p-cumaroil-β-icopiranosilcanferol (tilirosÃdeo), 6ââ-O-p-cumaroil-β-galactopiranosilcanferol e 6ââ-O-p-cumaroil-β-galactopiranosil-3â-metoxi canferol, alÃm dos esterÃides β-sitosterol e seu derivado 3-O-glicosilado. A determinaÃÃo estrutural de todos os metabÃlitos secundÃrios isolados foi realizada atravÃs do emprego de tÃcnicas espectromÃtricas como ressonÃncia magnÃtica nuclear de hidrogÃnio-1 e carbono-13 (RMN de 1H e de 13C uni e bidimensionais), espectroscopia na regiÃo do infravermelho (IV), espectrometria de massas de alta resoluÃÃo, obtida com ionizaÃÃo por electrospray e comparaÃÃo com dados da literatura. / The present work describes for the first time the chemical investigation from leaves of Croton pedicellatus Kunth. (Euphorbiaceae), a shrub, native to South America and popularly known as âvelameâ, name given to several Croton species. The ethanol extract from leaves was subjected to classical chromatographic procedures including high performance liquid chromatography (HPLC), resulting in the isolation of 15 secondary metabolites: two sesquiterpenes known as blumenol A and roseosÃdeo; five clerodane furan diterpenes: 12,20:15,16-diepoxy-3-hydroxy-7,20-dioxocleroda-13(16),14-dien-18,2-olide; methyl-12,20: 15,16-diepoxy-2,8-dihydroxy-3-acetoxy-7,20-dioxocleroda-13(16),14-dien-18-oate; methyl-12.20:15,16-diepoxy-2-hydroxy-3-acetoxy-7,20-dioxocleroda-13 (16),14-dien-18-oate; methyl-12,20:15,16-diepoxy-3,8- dihydroxy-2-acetoxy-7,20 -dioxocleroda-13(16),14-dien-18-oate; methyl-12,20:15,16-diepoxy-3-hydroxy-2-acetoxy-7,20-dioxocleroda-13(16),14-dien-18-oate, and six flavonoids: alpinumisoflavone, kaempferol, quercetin-3-glucoside, Kaempferol-3-β-D-(6-trans-p-coumaroyl)glucopyranoside (tiliroside), kaempferol-3-β-D-(6-trans-pcoumaroyl)galactopyranoside and kaempferol-3â-methoxy-3-β-D-(6-trans-pcoumaroyl)glucopyranoside, besides the steroids β-sitosterol and its derivative 3-glucosylated. The structure determination of all secondary metabolites isolated was performed by spectrometric techniques such as hydrogen-1 and carbon-13 nuclear magnetic resonance (1H NMR and 13C one/two- dimensional), infrared spectrometry (IR), high resolution mass spectrometry and comparison with literature data.

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