DEFAR - Artigos publicados em periódicos

URI permanente para esta coleçãohttp://www.hml.repositorio.ufop.br/handle/123456789/531

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2017 - 20192

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Assunto: search.filters.subject.Click chemistry

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    IR780-polymer conjugates for stable near-infrared labeling of biodegradable polyester-based nanocarriers.
    (2019) Oliveira, Maria Alice de; Machado, Marina Guimarães Carvalho; Silva, Sabrina Emanuelle Dias; Nascimento, Thais Leite; Lima, Eliana Martins; Lana, Gwenaelle Elza Nathalie Pound; Mosqueira, Vanessa Carla Furtado
    Near-infrared dyes are useful to monitor nanocarriers in vitro and in vivo and can serve as photosensitizers in cancer photodynamic therapy. However, strategies need to be developed to guarantee that the dye photophysical properties and loading within the drug delivery system remain stable for reliable tracking within biological systems. This work reports the facile chemical conjugation of the carbocyanine heptamethine near-infrared dye IR780 to polylactide for stable fluorescent labeling of biodegradable polyester nanocarriers. “Clickable” polylactide was synthesized via organocatalyzed ring opening polymerization of D,L-lactide with a cyclooctyne initiator. IR780 was derivatized and conjugated to polylactide via a one-pot copper-free azide-alkyne cycloaddition reaction. The synthetic strategy developed was effective to promote conjugation of the near-infrared fluorescent dye to polylactide, as confirmed by high performance liquid chromatography. Nanoparticles containing the dye–polymer conjugate were prepared by nanoprecipitation and characterized. Asymmetric flow field-flow fractionation with light scattering and fluorescence detection revealed that the near-infrared fluorescence of the nanoparticles remained stable and was not transferred to serum proteins. In contrast, significant transfer of the dye to serum proteins was evidenced when the dye was merely encapsulated in similar nanoparticles through physical entrapment. Confocal microscopy and fluorescence tomography imaging showed that the polymer-dye conjugate confers fluorescence properties to the NP suitable for further in vitro and in vivo pre-clinical studies.
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    Synthesis by click reactions and antiplasmodial activity of Lupeol 1,2,3-Triazole derivatives.
    (2017) Borgati, Tatiane Freitas; Pereira, Guilherme Rocha; Brandão, Geraldo Célio; Santos, Juliana de Oliveira; Fernandes, Dayane Aparecida Morais; Paula, Renata Cristina de; Nascimento, Maria Fernanda Alves do; Soares, Luciana Ferreira; Lopes, Júlio César Dias; Souza Filho, José Dias de; Oliveira, Alaíde Braga de
    Lupeol, a triterpene frequently found in Asteraceae plant species, showed moderate to low activity in different strains of Plasmodium falciparum, the most virulent malaria etiological agents. In this work, lupeol was isolated from Parahancornia fasciculata, a plant that is used to treat malaria in the Amazonia region. In the search of more activity lupeol derivatives, five new 1,2,3-triazole hybrid molecules were synthetized by copper-catalyzed azide-alkyne cycloaddition. The antiplasmodial activity of the semi-synthetic compounds were evaluated by the lactate dehydrogenase assay; the lupeol propargyl ether was the only one to disclosing increased activity (half maximal inhibitory concentration-IC50-62.0 ± 1.92 μmol L-1) in relation to lupeol (IC50 117.00 μmol L-1). Therefore, this work revealed a new class of interesting lupeol derivatives that can be obtained by linking electron donors to the hydroxy group at C-3.