DEFAR - Departamento de Farmácia

URI permanente desta comunidadehttp://www.hml.repositorio.ufop.br/handle/123456789/530

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2014 - 201932020 - 20211

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Autor: search.filters.author.Brandão, Geraldo CélioAssunto: search.filters.subject.Plasmodium falciparum

Resultados da Pesquisa

Agora exibindo 1 - 4 de 4
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    Extraction and fractionation effects on antiplasmodial activity and phytochemical composition of Palicourea hoffmannseggiana
    (2021) Ohashi, Leticia Hiromi; Gontijo, Douglas da Costa; Nascimento, Maria Fernanda Alves do; Margalho, Luciano Ferreira; Brandão, Geraldo Célio; Oliveira, Alaíde Braga de
    The present study on Palicourea hoffmannseggiana, which was collected at Marapanim, state of Pará, Brazil, comprises the preparation of different stem and leaf extracts and fractions. Ethanol, hydroethanol, and water extracts were prepared by several methods and evaluated for in vitro activity against resistant Plasmodium falciparum (W2 strain), disclosing a low parasite growth inhibition effect ( < 50 %). Dereplication by UPLC-DAD-ESI −MS of the leaf ethanol extract showed the presence of two known alkaloids, lyalosidic and strictosidinic acids, along with a sinapoyl ester of lyalosidic acid, with m/z 719.33 [M +H] + , which is possibly a new monoterpene indole alkaloid representative. Sequential liquid-liquid acid-base alkaloid separations from the leaf ethanol extract as well as directly from leaf powder afforded fractions of increased parasite growth inhibition, reaching up to 92.5±0.7%. The most bioactive fractions were shown to contain the β-carboline alkaloids harmane and 4-methyl-β-carboline, along with N-methyl-tryptamine and N-acetyl-tryptamine, while monoterpene indole alkaloids were detected in inactive fractions of these processes. The present results demonstrate that these preliminary fractionation methods can lead to significantly active fractions supporting an adequate scale-up to carrying out the isolation of anti-plasmodial compounds.
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    Bioprospection for antiplasmodial activity, and identification of bioactive metabolites of native plants species from the Mata Atlântica biome, Brazil.
    (2019) Gontijo, Douglas da Costa; Leite, João Paulo Viana; Nascimento, Maria Fernanda Alves do; Brandão, Geraldo Célio; Oliveira, Alaíde Braga de
    A total of 33 extracts of eleven different plants species from Mata Atlântica biome, Brazil, and different fractions of the bioactive extracts were evaluated against chloroquine-resistant Plasmodium falciparum W2 strain by PfLDH method and cytotoxicity to HepG2 cells by the MTT assay, and chemically characterized by LC-DAD-ESI-MS/MS analysis. The results allowed the identification of Alchornea glandulosa, Miconia latecrenata, and Psychotria suterella as the most active plant species. Different flavonoids and tannins in Alchornea glandulosa and Miconia latecrenata besides alkaloids in Psychotria suterella were identified. Bioguided fractionation of A. glandulosa and M. latecrenata leaves extracts led to fractions exhibiting high parasite growth inhibition. Seven known alkaloids were identified in the P. suterella extract, and of these, only 5-carboxystrictosidine had been assayed for antiplasmodial activity what points to this species as the most promising among the eleven one assayed.
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    In vitro antiplasmodial activity and identification, using tandem LC-MS, of alkaloids from Aspidosperma excelsum, a plant used to treat malaria in Amazonia.
    (2019) Nascimento, Myrth Soares do; Pina, Nayla di Paula Vieira; Silva, Andressa Santa Brigida da; Gomes, Luís Fabio dos Santos; Vasconcellos, Flávio de; Brandão, Geraldo Célio; Nascimento, Maria Fernanda Alves do; Oliveira, Alaide Braga de; Barbosa, Wagner Luiz Ramos
    Ethnopharmacological relevance: Aspidosperma excelsum Benth. (Apocynaceae), a native tree in the Brazilian Amazonia, is traditionally used to treat various diseases, including malaria. Aim of study: To investigate the chemical constitution, antiplasmodial activity and cytotoxicity of samples obtained from A. excelsum trunk bark by different procedures aiming to evaluate their potential as an antimalarial phytomedicine. Materials and methods: A hydroethanolic extract and alkaloid extracts were prepared and assayed for antiplasmodial activity and cytotoxicity against chloroquine-resistant Plasmodium falciparum (W2 strain) and HepG2 cells, respectively. Taking into account the known occurrence and antimalarial activity of Aspidosperma monoterpene indole alkaloids (MIA), acid-base extractions were carried out and the fractions were assayed for antiplasmodial activity and cytotoxicity. All the samples were analysed by hyphenated chromatographic techniques, such as UPLC-DAD-ESI-MS/MS and HRMS (HPLC-MS MicroTOF), comparing their chemical composition to the literature data. Results: The hydroethanolic extract disclosed a moderate in vitro activity against chloroquine-resistant Plasmodium falciparum (W2 strain) with IC50 23.68 ± 3.08 µg/mL), low cytotoxicity to HepG2 cells (> 250 µg/ mL) and good SI (> 10.56). A total of 20 known monoterpene indole alkaloids were identified, seven of which are here firstly described for A. excelsum. Known highly active alkaloids, namely demethylaspidospermine, aspidocarpine, and ochrolifuanine are present in active alkaloid fractions and might contribute to their observed antiplasmodial effect. An alkaloid fraction (Ae-Alk2), obtained directly from trunk bark by extraction with dil. aqueous HCl, pointed out for its activity (IC50 8.75 ± 2.26 µg/mL, CC50 185.14 ± 1.97 µg/mL, SI 21.16) and should be highlighted as the most promising out of the assayed samples. Conclusion: The present results represent a preliminary support to the alleged antimalarial use of A. excelsum trunk bark and allowed to highlight alkaloid fractions as promising phytomedicines.
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    7-Chloroquinolinotriazoles : synthesis by the azide-alkyne cycloaddition click chemistry, antimalarial activity, cytotoxicity and SAR studies.
    (2014) Pereira, Guilherme Rocha; Brandão, Geraldo Célio; Arantes, Lucas Micquéias; Oliveira Junior, Haliton Alves de; Paula, Renata Cristina de; Nascimento, Maria Fernanda Alves do; Santos, Fábio Mendes dos; Rocha, Ramon Kleber da; Lopes, Júlio César Dias; Oliveira, Alaíde Braga de
    Twenty-seven 7-chloroquinolinotriazole derivatives with different substituents in the triazole moiety were synthesized via copper-catalyzed cycloaddition (CuAAC) click chemistry between 4-azido-7- chloroquinoline and several alkynes. All the synthetic compounds were evaluated for their in vitro activity against Plasmodium falciparum (W2) and cytotoxicity to Hep G2A16 cells. All the products disclosed low cytotoxicity (CC50 > 100 mM) and five of them have shown moderate antimalarial activity (IC50 from 9.6 to 40.9 mM). As chloroquine analogs it was expected that these compounds might inhibit the heme polymerization and SAR studies were performed aiming to explain their antimalarial profile. New structural variations can be designed on the basis of the results obtained.