RESUMEN
The combinatorial chemistry has been an important tool for the development of new strategies against the Mycobacterium tuberculosis. Therefore, we evaluated the antimycobacterial activity of two coordinated metal complexes (Cu(II) and Co(II)) and a free ligand, including in the intramacrophage environment. The complexes were more active than the free ligand, indicating that the complexation favoured the antimicrobial activity. None of the compounds showed cytotoxic effect at the concentration of 200 µg ml-1 and both complexes showed intracellular antimicrobial activity, with results as effective as rifampicin. In this study, it was possible to identify complexes containing benzohydroxamate associated with transition metal ions (Cu2+ and Co2+ ), which were able to inhibit the growth of M. tuberculosis, including in persistence stage. In addition, the docking analysis allows inferring a possible interaction of the metal complexes with the enzyme urease, which has been reported as crucial for the bacillus survival in the intraphagosomal environment. Thus, these set of results demonstrate the potential of these metals in the development of new drugs against M. tuberculosis. SIGNIFICANCE AND IMPACT OF THE STUDY: In this study, it was possible to identify complexes containing benzohydroxamate associated with transition metals (Cu2+ and Co2+ ), which were able to inhibit the growth of Mycobacterium tuberculosis, including in the persistence stage. In this context, cobalt and copper can be scaffolds for new drugs against M. tuberculosis.
Asunto(s)
Antituberculosos/farmacología , Cobalto/farmacología , Cobre/farmacología , Macrófagos/microbiología , Mycobacterium tuberculosis/efectos de los fármacos , Antituberculosos/química , Cobalto/química , Cobre/química , Humanos , Ácidos Hidroxámicos/química , Pruebas de Sensibilidad Microbiana , Simulación del Acoplamiento Molecular , Mycobacterium tuberculosis/crecimiento & desarrolloRESUMEN
In recent times, however, due to the emergence of bacterial strains with resistance to conventional antibiotics, silver has again gained attention as an alternative for developing new efficient bactericides, including the use of silver nanoparticles (AgNPs). However, the improper disposal of these items after use may cause toxicological effects on organisms in the environment. To evaluate the potential environmental hazard of nanosilver-coated dressings, the nematode Caenorhabditis elegans was chosen as a test organism. The assays were conducted in 24-well plates that contain four different sizes of coated dressing to obtain different concentrations. L1 and L4 C. elegans larval stages were exposed to these nanosilver concentrations. Dressing cutouts were arranged between two layers of agar for 3 days and Escherichia coli (OP 50 strain) was added as food source for the worms. After the exposure period, growth, reproduction, fertility, silver concentration in the medium and the concentration of reactive oxygen species (ROS) in the worms were evaluated. Scanning and transmission electron microscopy analyses were performed on the coated dressings, as well as analyses of zeta potential, ionic release and antibacterial power in two bacterial strains (Pseudomonas aeruginosa and Staphylococcus aureus). It was verified the antibacterial power of the coated dressing, in both bacteria strains tested. Characterization of the coated dressing indicated heterogeneous nanoparticles, as well as distinct zeta potentials for the medium in water and saline medium (0.9% NaCl). L1 larval worms exposed to nanosilver-coated dressing showed a high ROS concentration and reductions in growth, fertility and reproduction. Worms exposed to the coated dressing during the L4 stage showed almost no response. Overall, the obtained results indicate the potential environmental hazard of nanosilver-coated dressings.