998 resultados para Tuberculosis activity
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Pós-graduação em Biotecnologia - IQ
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Despite the resistance developed by the Mycobacterium tuberculosis (MTb) strains, isoniazid (INK) has been recognized as one of the best drug for treatment of Tuberculosis (Tb). The coordination of INH to ruthenium metal centers was investigated as a strategy to enhance the activity of this drug against the sensitive and resistant strains of MTb. The complexes trans-[Ru(NH3)(4)(L)(INH)](2+) (L = SO2 or NH3) were isolated and their chemical and antituberculosis properties studied. The minimal inhibitory concentration (MIC) data show that [Ru(NH3)(5)(INH)](2+) was active in both resistant and sensitive strains, whereas free INK (non-coordinated) showed to be active only against the sensitive strain. The coordination of INH to the metal center in both [Ru(NH3)(5)(INH)](2+) and trans-[Ru(NH3)(4)(SO2)(INH)](2+) complexes led to a shift in the INH oxidation potential to less positive values compared to free INH. Despite, the ease of oxidation of INH did not lead to an increase in the in vitro INH activity against MTb, it might have provided sensitivity toward resistant strains. Furthermore, ruthenium complexes with chemical structures analogous to those described above were synthesized using the oxidation products of INK as ligands (namely, isonicotinic acid and isonicotinamide). These last compounds were not active against any strains of MTb. Moreover, according to DFT calculations the formation of the acyl radical, a proposed intermediate in the INH oxidation, is favored in the [Ru(NH3)(5)(INH)](2+) complex by 50.7 kcal mol(-1) with respect to the free INH. This result suggests that the stabilization of the acyl radical promoted by the metal center would be a more important feature than the oxidation potential of the INH for the antituberculosis activity against resistant strains. (C) 2015 Elsevier B.V. All rights reserved.
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In the search for new therapeutic tools against tuberculosis and to further address the therapeutic potential of pyridine-2-thiol 1-oxide (Hmpo) metal complexes, two new octahedral [M(III)(mpo)3] complexes, with M = Ga or Bi, were synthesized and characterized in the solid state and in solution. Attempts to crystallize [Ga(III)(mpo)3] in CH2Cl2 led to single crystals of the reaction product [GaCl(mpo)2], where the gallium(III) ion is in a square basis pyramidal environment, trans-coordinated at the basis to two pyridine-2-thiolato 1-oxide anions acting as bidentate ligands through their oxygen and sulfur atoms. The biological activity of the new [M(III)(mpo)3] complexes together with that of the previously reported Fe(III) analogous compound and the pyridine-2-thiol 1-oxide sodium salt (Na mpo) was evaluated on Mycobacterium tuberculosis. The compounds showed excellent activity, both in the standard strain H37Rv ATCC 27294 (pan-susceptible) and in five clinical isolates that are resistant to the standard first-line anti-tuberculosis drugs isoniazid and rifampicin. These pyridine-2-thiol 1-oxide derivatives are promising compounds for the treatment of resistant tuberculosis.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Background- The evaluation of the effects of new compounds and nonconventional anti-tuberculous drugs have grown and become increas-ingly more popular in recent years. Studies have shown anti-tuberculous activity for Ruthenium complexes, including organometallic com-pounds containing phosphine ligands such as picolinic acid generating great expectations and hopes. Methods- The Representational Difference Analysis (RDA) was applied in order to gain insight about differences in expression of Mycobacte-rium tuberculosis H37Rv exposed to [Ru(dppb)(pic)(bypy)] PF6 (SCAR1) and isoniazid (INH). Total RNA was extracted from the bacillus not exposed and exposed to SCAR1 and INH separately at concentration of MIC for 12 hours at 35°C. RDA was carried out and differentially expressed products were sequenced. Results- RDA-sequencing identified, for both compounds, orthologs that encode hypothetical and predict proteins. One related cell wall syn-thesis gene, identified by RDA, and genes related to INH target as inhA, katG and ahpC had their expression confirmed and quantified by real-time PCR. The gene encoding the cell wall associated hydrolase was induced 4.627 and 1.189, inhA 0.983 and 1.027, katG 1.111 and 1.345 and ahpC 1.063 and 1.039 fold after exposure to SCAR1 and INH respectively, compared to not exposed growth. Conclusion- The RDA brings, for the first time, directions to study related genes with metabolic pathways of SCAR1. RDA and Real-Time PCR highlight the idea that one of the SCAR1 interaction, in M tuberculosis may be in the cell wall biosynthesis considering the differential expression of a cell wall hydrolase and warrants further investigation.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)