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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.
151

ContribuiÃÃo ao conhecimento quÃmico de plantas do nordeste:Andira surinamensis e Piper divaricatum / Contribution to chemical knowledge of plants of northeast: Andira surinamensis e Piper divaricatum

Josà Gustavo Lima de Almeida 12 July 2007 (has links)
nÃo hà / Este trabalho descreve o estudo fitoquÃmico das cascas e do lenho de Andira surinamensis (Leguminosae), bem como a composiÃÃo quÃmica volÃtil dos Ãleos essenciais das folhas e frutos de Piper divaricatum G. Mey (Piperaceae). O estudo fitoquÃmico dos extratos de A. surinamensis, utilizando tÃcnicas clÃssicas de cromatografia em gel de sÃlica, resultou no isolamento de um dÃmero isoflavona inÃdito na literatura, 4â-metoxiisoflavona-(7-O-7ââ)-3âââ,4âââ- metilenodioxiisoflavona (Surinamensina), um triterpeno pentacÃclico comumente conhecido como Lupeol e mais quatro isoflavonas: 5,7-dihidroxi-4â-metoxiisoflavona (biochanina A), 5,4â- dihidroxi-7-metoxiisoflavona (prunetina), 7,3â-dihidroxi-4â-metoxiisoflavona (calicosina) e 5,7,3â-trihidroxi-4â-metoxiisoflavona (pratenseÃna). A determinaÃÃo estrutural dos compostos isolados foram elucidadas por tÃcnicas espectroscÃpicas tais como: espectro de massa, espectro de infravermelho e RessonÃncia MagnÃtica Nuclear de 1H, 13C uni e bidimensionais. A composiÃÃo quÃmica dos Ãleos essenciais das folhas e frutos de Piper divaricatum G. Mey., foram analisadas por CG / EM e CG / DIC. Um total de 24 compostos, representando mais do que 94% da composiÃÃo quÃmica dos Ãleos, foram identificados. Ambos os Ãleos mostraram grande concentraÃÃes de monoterpenos, em especial, o Ãleo das folhas que apresentou 81,1%. Os Ãleos mostraram composiÃÃo quÃmica similares, mas o Ãleo dos frutos pode ser facilmente distinguido do Ãleo das folhas pela exclusiva presenÃa do a-felandrene (4,60%), (E)-muurola- 4(14),5-dieno (9,0%) e do (E)-cariofileno (11,4%). Os maiores constituintes do Ãleo das folhas foram: linalool (23,4%), b-pineno (25,3%) e a-pineno (18,8%), enquanto que os Ãleo frutos apresentaram b-pineno (18.0%), a-pineno (17.6%) e (E)-cariofileno (11.4%), como compostos majoritÃrios. / This work describes the phytochemical investigation of extracts from the branch wood and branch barks of Andira surinamensis (Leguminosae), as well as, the volatile chemical composition of essential oil from leaves and fruits of Piper divaricatum G. Mey (Piperaceae). The phytochemical investigation of A. surinamensis extracts, using classic methods of chromatography on silica gel, yielded a novel isoflavone dimer, 4â-methoxyisoflavone-(7-O- 7ââ)-3âââ,4âââ-methylenedioxyisoflavone (surinamensin), along with the triterpene lupeol and the known isoflavones 5,7-dihydroxy-4\\\'-methoxyisoflavone (biochanin A), 5,4\\\'-dihydroxy-7- methoxyisoflavone (prunetin), 7,3â-dihydroxy-4â-methoxyisoflavone (calycosin) and 5,7,3â- trihydroxy-4â-methoxyisoflavone (pratensein). The structures of all isolated compounds were elucidated by spectroscopic methods, such as MS, IR and particularly 1D and 2D homonuclear and heteronuclear NMR spectroscopy and, comparison with published data for closely related compounds. The chemical composition of the essential oils from leaves and fruits of Piper divaricatum G. Mey., was analyzed by GC/MS and GC-FID. Twenty-four components, representing more than 94.0% of the chemical compositions of the oils, were identified. Both oils showed higher concentrations of monoterpenoids, particularly the oils from leaves (81.1%). The oils showed some compositional similarities but the fruit oil could be easily distinguished from the leaf oil by the exclusive presence of a-phellandrene (4.60%), (E)-muurola-4(14),5-diene (9,0%) and significant content of (E)-caryophyllene (11.4%). The major constituents of the leaf oils were linalool (23.4%), b-pinene (25.3%) and a-pinene (18.8%), while the fruit oils of the fruits contained b-pinene (18.0%) and a-pinene (17.6%) and (E)-caryophyllene (11.4%) as prevalent compounds.
152

Characterisation of oestrogenic properties of Isoflavones derived from Millettia griffoniana Baill.: - Molecular mode of action and tissue selectivity

Ketcha Wanda, Germain Jean Magloire 20 July 2006 (has links)
Six isoflavones derived from Millettia griffoniana namely, 4’-methoxy-7-O-[(E)-3-methyl-7hydroxymethyl-2,6 octadienyl]isoflavone (7-O-DHF), Griffonianone C (Griff C), 7-O-geranylformononetin (7-O-GF), 3’,4’-dihydroxy-7-O-[(E)-3,7-dimethyl-2,6-octadienyl]isoflavone (7-O-GISO), Griffonianone E (Griff E), 4’-O-geranylisoliquiritigenin (4-O-GIQ) were tested for potential oestrogenic activities in three different oestrogen receptor alpha (ERα) dependent assays, namely a recombinant yeast assay, a reporter gene assay based on stably transfected MCF-7 cells (MVLN cells) and the induction of alkaline phosphatase in Ishikawa cells. The oestrogenic activities of isoflavones from Millettia griffoniana could be completely suppressed by the pure oestrogen antagonist, fulvestrant. The expression of Ki-67, proliferating cell nuclear antigen (PCNA) and cyclin D1 (CD1) mRNA used as indicator of cell proliferation in MCF-7 cells was assayed. Based on these in vitro results, Griff C was further tested in vivo. The main objective of this part of the work was to study the mechanistic basis of the oestrogenicity Three different doses of Griff C (2, 10, or 20 mg/kg BW) of Griff C in ovariectomised Wistar rats. 17β-oestradiol (E2: 10 µg/kg BW) was used as positive control. They were treated daily for three consecutive days and sacrificed 24 hours after receiving the last dose. The whole uterus was removed and weight. Liver and vena cava fragments were also collected and stored together with uteri in liquid nitrogen for subsequent real-time PCR to evaluate the effects of Griff C on the regulation of some relevant oestrogen–responsive genes in the uterus, the liver and the vena cava. The role of Griff C in apoptosis or in cell survival, through mediation of the phosphatidylinositol 3 kinase-Akt (PI3K-Akt) signaling pathway, was also investigated. Western blot analysis revealed that Griff C slightly increased the phosphorylation of Akt at its serine 473 residue. In this work, oestrogenic properties of the isoflavones derived from Millettia griffoniana are described using reporter gene assays and the oestrogen-inducible alkaline phosphatase Ishikawa model for the first time. These in vitro data were verified in vivo showing the regulation of the expression of various relevant oestrogen-responsive genes by Griff C. The spectrum of its activity was clearly similar to that of 17β-oestradiol on uterine hepatic and vena cava tissues of ovariectomised rats except for the proliferative response. However Griff C remained 100 to 1000 times less effective than oestradiol. These findings confirmed that some of the biological effects attributed to Millettia griffoniana are closely related to oestrogen-mediated action.

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