DEFAR - Artigos publicados em periódicos
URI permanente para esta coleçãohttp://www.hml.repositorio.ufop.br/handle/123456789/531
Navegar
16 resultados
Resultados da Pesquisa
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 Flavonol triglycosides of leaves from Maytenus robusta with acetylcholinesterase inhibition.(2017) Sousa, Grasiely Faria de; Aguiar, Mariana Guerra de; Takahashi, Jacqueline Aparecida; Alves, Tânia Maria de Almeida; Kohlhoff, Markus; Vieira Filho, Sidney Augusto; Silva, Grácia Divina de Fátima; Duarte, Lucienir PainsAlthough Maytenus robusta aqueous infusions of leaves are used in Brazilian traditional medicine for stomach disease treatment, only a few chemical studies of this species are found in literature. The phytochemical investigation of methanol extract from M. robusta leaves yielded the known compound kaempferol (3) and two new flavonol glycosides: kaempferol-3-O-b-D-glucopyranosyl-(1 !3)-a-Lrhamnopyranosyl-( 1 ! 2)-b-D-glucopyranoside (1) and quercetin-3-O-b-D-glucopyranosyl-(1 !3)-a-Lrhamnopyranosyl-( 1 ! 2)-b-D-glucopyranoside (2). The chemical structures of 1 and 2 were elucidated by 1D/2D NMR, ESI–MS and ESI–MS2 spectral data. It is the first time flavonoids have been reported from M. robusta. Flavonols 1 and 2 showed 66% and 80% acetylcholinesterase (AChE) inhibition, compared to 93% of the standard eserine, by the Ellman’s method. These substances are one of the few active flavonols linked to a trisaccharide chain in the literature presenting this activity, and contribute to the screening for new types of natural AChE inhibitors.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 Constituents of fruit pulp of Maytenus salicifolia and complete 1D/2D NMR data of 3beta-hydroxy-D-B-friedo-olean-5-ene.(2010) Valladão, Frederico Nunes; Miranda, Roqueline Rodrigues Silva de; Oliveira, Gabriela Soares de; Silva, Grácia Divina de Fátima; Duarte, Lucienir Pains; Vieira Filho, Sidney AugustoA mixture of long-chain hydrocarbons constituted by nonacosane (29C, 7.5%), hentriacontane (31C, 48.3%), and tritriacontane (33C, 30.1%), the ester 1 -acetyloxymethylpentacosa-20 -enyl 10-hydroxydecanoate (2), -amyrin (3), friedelin (4), and lupeol (5), and 3 -hydroxy-D:B-friedo-olean-5-ene (6) were identified as constituents of fruits of Maytenus salicifolia Reissek (Celastraceae). The structural formula and the stereochemistry of compound 6 were established by the data obtained through 1H and 13C NMR spectroscopy, including DEPT-135 and 2D (HMQC, HMBC, and NOESY) experiments. By analysis of the spectral data, it was possible to correct seven chemical shift assignments of compound 6, which were erroneous attributed and published in the scientific literature.Item Antigiardial activity of the hexane extract of Maytenus gonoclada mart.(2012) Silva, Fernando César; Busatti, Haendel Gonçalves Nogueira Oliveira; Gomes, Maria Aparecida; Duarte, Lucienir Pains; Silva, Grácia Divina de Fátima; Vieira Filho, Sidney AugustoPlants of the Maytenus genus have been used in folk medicine in Brazil for treatment of gastrointestinal motility disturbances such as diarrhea. The present study was performed to evaluate antigiardial activity of the hexane extract and triterpenes isolated from the branches of Maytenus gonoclada Mart. (Celastraceae). The hexane extract and triterpenes were examined for antigiardial activity using the colorimetric method against Giardia lamblia (ATCC 30888). The hexane extract exhibited antigiardial activity. This result may partly explain and support the use of plants of the Maytenus genus for the treatment of diarrhea in folk medicine in Brazil.Item Pentacyclic triterpenes from branches of Maytenus robusta and in vitro cytotoxic property against 4T1 cancer cells.(2014) Sousa, Grasiely Faria de; Soares, Daniel Crístian Ferreira; Mussel, Wagner da Nova; Pompeu, Nana Flora Elias; Silva, Grácia Divina de Fátima; Vieira Filho, Sidney Augusto; Duarte, Lucienir PainsDois novos friedelanos, 1 e 2, e cinco triterpenos pentacíclicos conhecidos foram isolados dos galhos de Maytenus robusta. Suas estruturas químicas foram identificadas como 3,16-dioxo-29- hidroxifriedelano (1), 3-oxo-16b,29-di-hidroxifriedelano (2), 3-oxofriedelano (3), 3b-friedelinol (4), 3,16-dioxofriedelano (5), 3-oxo-29-hidroxifriedelano (6) e 3,16-dioxo-12a-hidroxifriedelano (7). A estrutura e estereoquímica dos triterpenos 1 e 2 foram estabelecidas por infravermelho (IR), ressonância magnética nuclear (NMR) 1D/2D, espectrometria de massas de alta resolução com ionização química à pressão atmosférica (HR-APCIMS) e difração de raios X de pó. A atividade citotóxica in vitro dos triterpenos 1 a 6 foi avaliada frente a células de câncer de mama murino. Os triterpenos 1 e 2 apresentaram atividade citotóxica contra células 4T1 em baixa concentração.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.Item Antioxidant activity of Maytenus imbricata Mart., Celastraceae.(2009) Silva, Grácia Divina de Fátima; Souza, Silvia Ribeiro de; Barbosa, Luiz Cláudio de Almeida; Duarte, Lucienir Pains; Ribeiro, Sônia Machado Rocha; Queiroz, José Humberto de; Vieira Filho, Sidney Augusto; Oliveira, Márcio L. R.A atividade antioxidante, poder redutor (RP) e a atividade coletora de radicais livres (FRS) usando 2,2-difenil- 1-picrilhidrazil (DPPH), e a concentração de substâncias fenólicas totais dos extratos e substâncias isoladas das folhas, caules e raízes de Maytenus imbricata Mart. (Celastraceae) foram avaliados. Alguns extratos, a mistura de compostos fenólicos e epicatequina mostraram alto poder redutor e atividade antioxidante (DPPH) em comparação com o padrão butilhidroxianisol (BHA) e ácido gálhico (GA) utilizados no ensaio. O extrato acetato de etila das folhas mosraram alto teor de substâncias fenólicas e alto poder redutor e atividade antioxidante em relação aos outros extratos. Este fato indica haver alguma relação entre a concentração de substâncias fenólicas e o poder redutor. O solvente usado no processo de extração influencia a composição química dos extratos e, consequentemente, as atividades redutoras e antioxidantes.Item Four Brazilian Maytenus salicifolia Reissek (Celastraceae) groups studied by TLC and UV/Vis spectrophotometry.(2009) Valladão, Frederico Nunes; Miranda, Roqueline Rodrigues Silva de; Vale, Fernando Henrique Aguiar; Valladao, Sara Araujo; Silva, Grácia Divina de Fátima; Duarte, Lucienir Pains; Okano, Rita Maria de Carvalho; Messias, Maria Cristina Teixeira Braga; Vieira Filho, Sidney AugustoA grande variedade de angiospermas apontou a necessidade do desenvolvimento de sistemas de classificação botânica apoiada pela fitoquímica, bioquímica e outras. Recentemente, técnicas de análise utilizadas para o isolamento e caracterização de metabólitos secundários vêm sendo empregadas como métodos auxiliares rápidos e eficientes para identificação e classificação de espécies vegetais. M. salicifolia é popularmente conhecida no Brasil, como “cafezinho”. O chá obtido a partir de folhas frescas é usado topicamente para aliviar pruridos e sintomas alergiformes. Este trabalho apresenta a utilização do CCD em sílica gel e espectrofotometria no UV / Vis como métodos auxiliares na identificação botânica de M. salicifolia. Os resultados demonstraram que este processo pode ser usado na diferenciação de plantas do mesmo gênero, assim como detectar variações químicas entre indivíduos de uma mesma espécie.