Browsing by Autor "David Gutierrez-Yapu"

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    Antiprotozoal activity of Betulinic acid derivatives
    (Elsevier BV, 2009) Dafne B Domínguez-Carmona; Fabiola Escalante‐Erosa; Karlina García‐Sosa; Grace Ruiz-Pinell; David Gutierrez-Yapu; Manuel Jesús Chan-Bacab; Alberto Giménez-Turba; Luis M. Peña-Rodrı́guez
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    Drimanes from Drimys brasiliensis with leishmanicidal and antimalarial activity
    (Instituto Oswaldo Cruz, Ministério da Saúde, 2013) Vanessa D. Claudino; Kesia Caroline da Silva; Valdir Cechinel Filho; Rosendo A. Yunes; Franco Delle Monachè; Alberto Giménez; Efraín Salamanca; David Gutierrez-Yapu; Ângela Malheiros
    This paper evaluates CHCl3 and CH3OH extracts of the stem bark, branches and leaves of Drimys brasiliensis and drimane sesquiterpenes isolated from the stem bark against strains of Leishmania amazonensis and Leishmania braziliensis promastigotes and Plasmodium falciparum trophozoites. All of the extracts and compounds were tested in cell lines in comparison with reference standards and cell viability was determined by the XTT method. The CHCl3 and CH3OH extracts from the stem bark and branches yielded promising results against two strains of Leishmania, with 50% inhibitory concentrations (IC50 ) values ranging from 39-100 µg/mL. The CHCl3 extract of the stem bark returned IC50 values of 39 and 40.6 µg/mL for L. amazonensis and L. braziliensis, respectively. The drimanes were relatively effective: 1-β-(p-coumaroyloxy)-polygodial produced IC50 values of 5.55 and 2.52 µM for L. amazonensis and L. braziliensis, respectively, compared with 1-β-(p-methoxycinnamoyl)-polygodial, which produced respective IC50 values of 15.85 and 17.80 µM. The CHCl3 extract demonstrated activity (IC50 of 3.0 µg/mL) against P. falciparum. The IC50 values of 1-β-(p-cumaroyloxyl)-polygodial and 1-β-(p-methoxycinnamoyl)-polygodial were 1.01 and 4.87 µM, respectively, for the trophozoite strain. Therefore, the results suggest that D. brasiliensis is a promising plant from which to obtain new and effective antiparasitic agents.
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    Evaluation of Antileishmanial Activity of Selected Brazilian Plants and Identification of the Active Principles
    (Hindawi Publishing Corporation, 2013) Valdir Cechinel Filho; Christiane Meyre‐Silva; Rivaldo Niero; Luísa Nathália Bolda Mariano; Fabiana Gomes do Nascimento; Ingrid Vicente Farias; Vanessa Fátima Gazoni; Bruna dos Santos Silva; Alberto Giménez; David Gutierrez-Yapu
    This study evaluated extracts, fractions, and isolated compounds from some selected Brazilian medicinal plants against strains of promastigotes of Leishmania amazonensis and L. brasiliensis in vitro. The cell viability was determined, comparing the results with reference standards. The dichloromethane fractions of the roots, stems, and leaves of Allamanda schottii showed IC50 values between 14.0 and 2.0 μ g/mL. Plumericin was the main active compound, with IC50 of 0.3 and 0.04 μ g/mL against the two species of Leishmania analyzed. The hexane extract of Eugenia umbelliflora fruits showed IC50 of 14.3 and 5.7 μ g/mL against L. amazonensis and L. brasiliensis, respectively. The methanolic extracts of the seeds of Garcinia achachairu and guttiferone A presented IC50 values of 35.9 and 10.4 μ g/mL, against L. amazonensis, respectively. The ethanolic extracts of the stem barks of Rapanea ferruginea and the isolated compound, myrsinoic acid B, presented activity against L. brasiliensis with IC50 of 24.1 and 6.1 μ g/mL. Chloroform fraction of Solanum sisymbriifolium exhibited IC50 of 33.8 and 20.5 μ g/mL, and cilistol A was the main active principle, with IC50 of 6.6 and 3.1 μ g/mL against L. amazonensis and L. brasiliensis, respectively. It is concluded that the analyzed plants are promising as new and effective antiparasitic agents.
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    <i>In vitro</i> Antiprotozoal Activity and Chemical Composition of <i>Ambrosia tenuifolia</i> and <i>A. scabra</i> Essential Oils
    (SAGE Publishing, 2008) Valeria P. Sülsen; Silvia I. Cazorla; Fernanda M. Frank; Paola M. R. Di Leo Lira; Claudia Anesini; David Gutierrez-Yapu; Alberto Giménez-Turba; Arnaldo L. Bandoni; Emilio L. Malchiodi; Liliana Muschietti
    The in vitro antimalarial, trypanocidal and leishmanicidal activities and the chemical composition of Ambrosia tenuifolia and A. scabra essential oils were investigated. The oils, obtained by hydrodistillation of the aerial parts, showed significant antimalarial activity against the chloroquine sensitive (F32) and the chloroquine resistant (W2) strains of Plasmodium falciparum with 50% inhibitory concentration (IC 50 ) values ranged from 2.8 to 7 μg/mL. Against Trypanosoma cruzi epimastigotes, only A. tenuifolia exerted slight activity (IC 50 = 59.7 μg/mL). None of the essential oils showed toxicity towards Leishmania mexicana. Cytotoxicity for murine T-lymphocytes was compared with the parasiticidal activity by using the selectivity index (SI) ratio. The chemical composition of A. tenuifolia and A. scabra essential oils was analyzed by GC-FID-MS. Thirty-eight and twenty-four compounds were identified in A. tenuifolia and A. scabra, respectively. The major constituents of A. tenuifolia oil were germacrene D (22.9%) and bicyclogermacrene (14.2%), while the oil of A. scabra contained limonene (22.0%), caryophyllene oxide (13.8%) and ( E)-caryophyllene (13.5%). This is the first time that the antiprotozoal activity of both oils and the chemical composition of A. scabra essential oil have been reported.
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    Metabolites from roots of Colubrina greggii var. yucatanensis and evaluation of their antiprotozoan, cytotoxic and antiproliferative activities
    (Brazilian Chemical Society, 2011) Dafne B Domínguez-Carmona; Fabiola Escalante‐Erosa; Karlina García‐Sosa; Grace Ruiz-Pinell; David Gutierrez-Yapu; Manuel Jesús Chan-Bacab; Rosa Moo‐Puc; Nigel C. Veitch; Alberto Giménez-Turba; Luis M. Peña-Rodrı́guez
    A purificao do extrato da raiz de Colubrina greggii var. yucatanensis levou ao isolamento e identificao do cido 3-O-acetil ceantico, um novo triterpeno natural, juntamente com os metablitos j descritos: cido ceantico, cido cenotnico, cido betulnico, discarina B e crisofanena. Os produtos naturais e os derivados semi-sintticos ster de acetil dimetil ceanotato, dimetil ceanotato e peracetato de crisofanena mostraram moderada a baixa atividade leishmanicida e tripanocida. Nenhum dos metablitos mostrou ser citotxicos ou ter atividade antiproliferativa. Os resultados tambm sugerem que o cido betulnico contribui para a atividade antiplasmdica inicialmente detectada na raiz do extrato bruto de C. greggii var. yucatanensis