DEFAR - Artigos publicados em periódicos
URI permanente para esta coleçãohttp://www.hml.repositorio.ufop.br/handle/123456789/531
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Resultados da Pesquisa
Item Potencial fitotóxico de Pterodon polygalaeflorus Benth (Leguminosae) sobre Acanthospermum australe (Loefl.) O. Kuntze e Senna occidentalis (L.).(2009) Belinelo, Valdenir José; Vieira Filho, Sidney Augusto; Almeida, Marcelo Suzart de; Alves, Dalton Luiz FerreiraO objetivo dessa pesquisa foi sintetizar e caracterizar a atividade alelopática de derivados do ácido 6α,7β–di-hidroxivouacapan-17β–óico, isolado de sementes de Pterodon polygalaeflorus Benth (Leguminosae). A caracterização dos compostos envolveu espectrometria no infravermelho (IV) e ressonância magnética nuclear de hidrogênio e de carbono (RMN de 1H e de 13C) incluindo experimentos em duas dimensões (COSY 1H 1H, HMQC e HMBC). Os efeitos alelopáticos foram avaliados através de bioensaios de germinação de sementes e crescimento radicular, em condições controladas de temperatura (25 °C) e fotoperíodo (12 h claro/12h escuro), durante 72 horas. Concentrações de 1,0, 100,0 e 1000,0 mg.L-1 foram testadas. Senna occidentalis (fedegoso) e Acanthospermum australe (carrapichinho) foram utilizadas como espécies daninhas alvo. Foi observado que o efeito alelopático dos compostos aumentou em função do aumento da concentração, mostrando assim uma relação dose dependente. A tendência geral observada nos resultados foi de aumento da intensidade dos efeitos alelopáticos inibitórios em função do aumento da concentração. A N-Etil-6α-acetoxi-7β- hidroxivouacapan-17β–amida e N,N-Dietil-6α-acetoxi-7β-hidroxivouacapan-17β–amida foram os derivados que apresentaram maior efeito inibidor da germinação e do crescimento radicular do fedegoso e do carrapichinho. Portanto, esses compostos representam grande potencial aleloquimico contra essas ervas daninha.Item Complete assignment of the 1H and 13C NMR spectra of a new polyester sesquiterpene from Austroplenckia populnea.(2000) Vieira Filho, Sidney Augusto; Duarte, Lucienir Pains; Santos, Marcelo Henrique dos; Silva, Grácia Divina de Fátima; Lula, Ivana Silva; Afonso, Robson José de Cássia Franconew polyester sesquiterpene (4-hydroxy-1,2,6,15-tetraacetyl-9-benzoylagarofuran), together with known friedelane triterpenes (friedelin, -friedelinol and 28-hydroxyfriedelin), was isolated from the leaves of Austroplenckia populnea. The structure and relative stereochemistry of the new ester were based on 2D NMR spectroscopic techniques including HMBC, HMQC and NOESY.Item Triterpene esters isolated from leaves of Maytenus salicifolia Reissek.(2007) Miranda, Roqueline Rodrigues Silva de; Silva, Grácia Divina de Fátima; Duarte, Lucienir Pains; Vieira Filho, Sidney AugustoThe triterpene ester (3b)-olean-18-en-3-yl stearate (1), together with (3b)-urs-12-en-3-yl stearate (2), and (3b)-lup-20(29)-en-3-yl stearate (3) were isolated from leaves of Maytenus salicifolia Reissek (Celastraceae). The structure of 1, a new compound, including its configuration, was established by 1H, 13C, and DEPT-135 NMR data, including 2D experiments( HSQC, HMBC, COSY, and NOESY). The molecular mass (692 Da) was confirmed by gas chromatography coupled with mass spectrometry (CG/ MS).Item Total assignment of 1H and 13C NMR spectra of two 3,4-secofriedelanes from Austroplenckia populnea.(2001) Vieira Filho, Sidney Augusto; Duarte, Lucienir Pains; Silva, Grácia Divina de Fátima; Lula, Ivana Silva; Santos, Marcelo Henrique dosTwo new 3,4-secofriedelanes, 3,4-seco-28-hydroxyfriedelan-3-oic acid (1) and 3,4-secofriedelan-3-oic acid (2),were isolated from the leaves of Austroplenckia populnea (Celastraceae).The structureswere established by 2D NMR spectroscopic techniques (COSY, HMQC, HMBC and NOESY).Item Structural determination of 3beta-stearyloxy-urs-12-ene from Maytenus salicifolia by 1D and 2D NMR and quantitative 13C NMR spectroscopy.(2006) Miranda, Roqueline Rodrigues Silva de; Silva, Gracia Divina de Fátima ; Duarte, Lucienir Pains; Fortes, Isabel Cristina Pereira; Vieira Filho, Sidney AugustoSix pentacyclic triterpenoids, 3b-stearyloxy-urs-12-ene (1), friedelin (2), 3b-friedelinol (3), a-amyrin (4), b-amyrin (5), and lupeol (6), have been isolated from the hexane extract of Maytenus salicifolia Reissek (Celastraceae) leaves. The molecular and structural formula as well as the stereochemistry of a new pentacyclic triterpene (1) were determined using data obtained from 1H and 13C NMR spectra, DEPT135 and by 2D HSQC, HMBC, COSY and NOESY experiments. The molecular formula C48H84O2 was established using quantitative 13C NMR, and the molecular weight (692 Da) was confirmed by elemental analysis and mass spectrometry (GC-MS).Item Lupane Pentacyclic triterpenes isolated from stems and branches of Maytenus imbricata (Celastraceae).(2005) Silva, Silvia Ribeiro de Souza e; Silva, Gracia Divina de Fátima ; Barbosa, Luca Cláudio de Almeida ; Duarte, Lucienir Pains; Vieira Filho, Sidney AugustoFour lupane pentacyclic triterpenes were isolated from the hexane extract of stems and branches of Maytenus imbricata Mart.ex Reissek: 3-oxolup-20(30)-en-29-al (1), 30-hydroxylup-20(29)-en-3-one (2), (11α)-11-hydroxylup-20(29)-en-3-one (3), and (3β)-lup-20(30)-ene-3,29-diol (4). The structural identification of 1–4 was achieved by 1H- and 13C-NMR techniques, including 2D experiments (HSQC, HMBC, and NOESY).Item Alelopatia de Arctius minus Bernh, (Asteraceae) na germinação e crescimento radicular de sorgo e pepino.(2008) Belinelo, Valdenir José; Czepak, Márcio Paulo; Vieira Filho, Sidney Augusto; Menezes, Luis Fernando Tavares de; Jamal, Claúdia MasrouahOs objetivos deste trabalho foram identificar e caracterizar a atividade alelopática de extratos obtidos do vegetal Arctium minus (Hill) Bernh (Asteraceae). Foram avaliados a atividade fitotóxica de extratos orgânicos (1 e 100 mg.L-1) e do extrato aquoso (5,00 e 0,05% m/v), sobre a germinação e crescimento radicular de sementes da monocotiledônea Sorghum bicolor L. (sorgo) e da dicotiledônea Cucumis sativus L. (pepino). Os resultados mostraram a presença de atividade alelopática inibitória variável de acordo com a concentração do extrato e com a planta alvo. A intensidade do efeito inibitório induzido foi maior para o extrato etanólico na concentração 100 mg.L-1 para Sorghum bicolor L. Os resultados também indicaram a existência de potencial de utilização do extrato etanólico de Arctium minus (Hill) Bernh como herbicida natural e abriu perspectivas para a pesquisa da(s) substância(s) de maior atividade aleloquímica.Item 3-beta-(Stearyloxy)olean-12-ene from Austroplenckia populnea : structure elucidation by 2D-NMR and quantitative 13C-NMR spectroscopy.(2003) Vieira Filho, Sidney Augusto; Duarte, Lucienir Pains; Silva, Grácia Divina de Fátima; Howarth, O. W.; Lula, Ivana Silva3 -(Stearyloxy)olean-12-ene was isolated from a hexane extract of Austroplenckia populnea Reiss (Celastraceae) leaves. The structure was solved by means of quantitative 13C-NMR, HMBC, HMQC, COSY, NOESY, and NOE difference spectra. The mass spectrum showed an [M 1] ion peak at m/z 693, and the molecular formula C48H84O2 was confirmed by combustion analysis.Item Anti-trypanosomal activity of pentacyclic triterpenes isolated from Austroplenckia populnea (Celastraceae).(2002) Duarte, Lucienir Pains; Vieira Filho, Sidney Augusto; Silva, Grácia Divina de Fátima; Sousa, José Rego de; Pinto, Artur da SilveiraFour pentacyclic triterpenes isolated from Austroplenckia populnea and four compounds of known anti T. cruzi or anti-malarial activity were tested. Of those triterpenes tested 20_-hydroxy-tingenone showed high activity, epikatonic acid was less active, while populnilic and populninic acids were inactive against the trypanosome of the subgenus Schizotrypanum tested. Benzonidazole, nifurtimox, ketoconazole and primaquine presented a remarkable dose-dependent inhibitory effect reaching practically to a total growth inhibition of the parasite at the end of incubation time. The trypanosome tested appear to be a suitable model for preliminary screen for anti T. (S.) cruzi compounds.Item Stereochemistry of 16α-hydroxyfriedelin and 3-oxo-16-methylfriedel-16-ene established by 2D NMR spectroscopy.(2009) Duarte, Lucienir Pains; Miranda, Roqueline Rodrigues Silva de; Rodrigues, Salomão Bento Vasconcelos; Silva, Grácia Divina de Fátima; Vieira Filho, Sidney Augusto; Knupp, Vagner FernandesFriedelin (1), 3β-friedelinol (2), 28-hydroxyfriedelin (3), 16α-hydroxyfriedelin (4), 30-hydroxyfriedelin (5) and 16α,28-dihydroxyfriedelin (6) were isolated through fractionation of the hexane extract obtained from branches of Salacia elliptica. After a week in CDCl3 solution, 16α-hydroxyfriedelin (4) reacted turning into 3-oxo-16- methylfriedel-16-ene (7). This is the first report of a dehydration followed by a Nametkin rearrangement of a pentacyclic triterpene in CDCl3 solution occurring in the NMR tube. These seven pentacyclic triterpenes was identified through NMR spectroscopy and the stereochemistry of compound 4 and 7 was established by 2D NMR (NOESY) spectroscopy and mass spectrometry (GC-MS). It is also the first time that all the 13C-NMR and 2D NMR spectral data are reported for compounds 4 and 7.