Browsing by Author "Lula, Ivana Silva"

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    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 Silva
    3 -(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.
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    Chemical constituents from branches of Maytenus gonoclada (Celastraceae) and evaluation of antimicrobial activity.
    (2011) Silva, Fernando César; Duarte, Lucienir Pains; Silva, Grácia Divina de Fátima; Vieira Filho, Sidney Augusto; Lula, Ivana Silva; Takahashi, Jacqueline Aparecida; Sallum, William S. T.
    Seis triterpenos pentacíclicos isolados dos galhos de Maytenus gonoclada (Celastraceae), incluindo todos os dados de RMN do novo composto 3-oxo-12α,29-diidroxifriedelano são aqui relatados. A estereoquímica do novo friedelano foi estabelecida por dados de RMN bidimensional (HSQC, HMBC e NOESY), e sua massa molecular confirmada por espectrometria de massas (ESI). Testes de atividade antimicrobiana usando método de difusão em disco e de macrodiluição foram realizados contra as bactérias Escherichia coli, Citrobacter freundii e Bacillus cereus, e contra o fungo Candida albicans. O triterpeno 3-oxo-12a-hidroxifriedelano mostrou resultado positivo contra C. albicans.
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    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 Franco
    new 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.
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    Complete assignment of the 1H and 13C NMR spectra of the tetraisoprenylated benzophenone 15-epiclusianone.
    (2001) Santos, Marcelo Henrique dos; Nagem, Tanus Jorge; Braz Filho, Raimundo; Lula, Ivana Silva; Speziali, Nivaldo Lucio
    An NMR study of 15-epiclusianone, 1-benzoyl-6-hydroxy-14,14-dimethyl-3,5,15-tri(3-methyl-2-butenyl)- bicyclo[3.3.1]non-1-ene-4,6-dione (1), a novel tetraisoprenylated benzophenone isolated from pericarp of fruits of Rheedia gardneriana, is described. In addition to conventional 1D NMR techniques, 2D shiftcorrelated NMR experiments [1H 1H-COSY, 1H 13C-HMQC-1J(C,H), 1H 13C-HMBC-nJ(C,H) (n = 2 and 3) and 1H 1H-NOESY] were used for 1H and 13C chemical shift assignments of this natural product. The 1D 13C NMR spectrum of 1 in the solid state was also obtained.
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    Structural and physical–chemical evaluation of bradykinin potentiating peptide and its high soluble supramolecular complex.
    (2010) Sousa, Frederico Barros de; Denadai, Ângelo Márcio Leite; Lula, Ivana Silva; Ianzer, Danielle Alves; Malaspina, Érica Resende; Camargo, Antônio Carlos Martins de; Santos, Robson Augusto Souza dos; Sinisterra, Ruben Dario
    The supramolecular interactions between a Bradykinin Potentiating Peptide (BPP10c) and b-cyclodextrin (bCD) have been investigated by using several techniques. These new properties acquired by the inclusion phenomena are important in developing a strategy for pharmaceutical formulation. The BPP10c structural elucidation and its inclusion complex formed have been investigated using Nuclear Magnetic Resonance techniques. The peptide secondary structure was investigated using infrared spectroscopy in solution, Circular Dichroism and NMR. In addition, the thermodynamic parameters of the inclusion process were also evaluated using Isothermal Titration Calorimetry. The results obtained by these physical– chemical techniques suggested a 1:1 complex formed by interaction between the Tryptophan amino acid residue and the bCD cavity. The peptide secondary structure was not substantially modified for the inclusion process. In addition, the inclusion process proved to be spontaneous (DG8 = -2.53 kcal mol-1), with an enthalpy reduction (DH8 = -3.72 kcal mol-1) and a favored entropic variation (TDS8 = -1.19 kcal mol-1).
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    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 dos
    Two 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).
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    Two epimeric friedelane triterpenes isolated from Maytenus truncata Reiss : 1H and 13C chemical shift assignments.
    (2000) Meléndez Salazar, Gloria Del Carmen; Silva, Grácia Divina de Fátima; Duarte, Lucienir Pains; Lula, Ivana Silva
    An NMR study of 3˛- and 3ˇ-friedelinol is described. In addition to conventional 1D NMR methods, 2D shift-correlated NMR experiments HMQC [(1J(C,H)], HMBC [nJ(C,H); n D 2 and 3] and 2D 1H,1H-NOESY were used for 1H and 13C chemical shift assignments of these triterpenes.