ABSTRACT
Candida spp. cause invasive fungal infections. One species, Candida glabrata, may present intrinsic resistance to conventional antifungal agents, thereby increasing mortality rates in hospitalized patients. In this context, metal complexes present an alternative for the development of new antifungal drugs owing to their biological and pharmacological activities demonstrated in studies in the last decades. Accordingly, in this study we have synthesized and characterized two new Co(II) complexes with thiocarbamoyl-pyrazoline ligands to assess their antimicrobial, mutagenic, and cytotoxic potential. For antimicrobial activity, the broth microdilution method was performed against ATCC strains of Candida spp. and fluconazole dose-dependent isolates of C. glabrata obtained from urine samples. The Ames test was used to assess mutagenic potential. The reduction method of the MTS reagent (3 [4,5-dimethylthiazol-2-yl]-5-[3-carboxymethoxyphenyl]-2-[4-sulfophenyl]-2H-tetrazolium) was performed with HeLa, SiHa, and Vero cells to determine cytotoxicity. Both complexes exhibited fungistatic and fungicidal activity for the yeasts used in the study, demonstrating greater potential for C. glabrata ATCC 2001 and the C. glabrata CG66 isolate with a Minimum Inhibitory Concentration MIC from 3.90 to 7.81 µg mL-1 and fungicidal action from 7.81 to 15.62 µg mL-1. The complexes inhibited and degraded biofilms by up to 90% and did not present mutagenic and cytotoxic potential at the concentrations evaluated for MIC. Thus, the complexes examined herein suggest promising alternatives for the development of new antifungal drugs.
Subject(s)
Antifungal Agents/chemistry , Antifungal Agents/pharmacology , Cobalt/chemistry , Coordination Complexes/chemistry , Pyrazoles/chemistry , Thiocarbamates/chemistry , Animals , Biofilms/drug effects , Candida glabrata/drug effects , Chlorocebus aethiops , Coordination Complexes/pharmacology , Crystallography, X-Ray , HeLa Cells , Humans , Ligands , Microbial Sensitivity Tests , Molecular Structure , Spectrum Analysis/methods , Vero CellsABSTRACT
In this study, we describe the synthetic approach, crystallographic structure, luminescent behavior and elucidation of the channels of the energy conversion in heteronuclear coordination polymers with emission in the visible (Eu(3+) and organic ligand) and near-infrared (Nd(3+)) range. The [(Nd0.9Eu0.1)2(dipc)3(H2O)3]n·nH2O, [(Nd0.7Eu0.3)2(dipc)3(H2O)3]n·nH2O, [(Nd0.5Eu0.5)2(dipc)3(H2O)3]n·nH2O, [(Nd0.3Eu0.7)2(dipc)3(H2O)3]n·nH2O, [(Nd0.1Eu0.9)2(dipc)3(H2O)3]n·nH2O, [Eu2(dipc)3(H2O)3]n·nH2O and [Nd2(dipc)3(H2O)3]n·nH2O materials are obtained by hydrothermal conditions from pyridine-2,6-dicarboxylic acid (H2dipc) and Ln2O3 oxide (Ln = Eu and Nd). The fine structures in the emission spectrum and spectral profile are used to investigate the ion responsible for the emission characteristics of a material (6), based on coordination polyhedron. The heteronuclear systems show emission in the dual spectral range (NIR-VIS) tuned for blue or red. The tuning of emission on the red (Eu(3+)) or blue (organic ligand) range may be performed by controlling the stoichiometric ratio of the lanthanide ions and by controlling the excitation wavelength. Nd(3+) ions display self-absorption of emission to dipc ligand, resulting in interference on the emission band profile ranging from 400 to 600 nm. The energetic process of energy transfer is operated by a cascade of energy transfer, from dipc ligand mainly to Eu(3+) ions and finishing on the Nd(3+) ion. The efficient sensitization to Nd(3+) by Eu(3+) ions is due to the presence of many resonant energy levels and the short distance between these ions.
