Synthesis, characterization and biological studies of a cobalt(III) complex of sulfathiazole.

The emergence of old and new antibiotic resistance created in the last decades revealed a substantial medical need for new classes of antimicrobial agents. The antimicrobial activity of sulfa drugs is often enhanced by complexation with metal ions, which is in concordance with the well-known importance of metal ions in biological systems. Besides, sulfonamides and its derivatives constitute an important class of drugs, with several types of pharmacological agents possessing antibacterial, anti-carbonic anhydrase, diuretic, hypoglycemic, antithyroid, antiviral and anticancer activities, among others. The purpose of this work has been the obtainment, characterization and determination of biological properties (antibacterial, antifungal, mutagenicity and phytotoxicity) of a new Co(III)-sulfathiazole complex: Costz, besides of its interaction with bovine serum albumin (BSA). The reaction between sodium sulfathiazole (Nastz) and cobalt(II) chloride in the presence of H2O2 leads to a brown solid, [CoIII(stz)2OH(H2O)3], (Costz). The structure of this compound has been examined by means of elemental analyses, FT-IR, 1H NMR, UV-Visible spectrometric methods and thermal studies. The Co(III) ion, which exhibits a distorted octahedral environment, could coordinate with the N thiazolic atom of sulfathiazolate. The complex quenched partially the native fluorescence of bovine serum albumin (BSA), suggesting a specific interaction with the protein. The Costz complex showed, in vitro, a moderate antifungal activity against Aspergillus fumigatus and A. flavus. As antibacterial, Costz displayed, in vitro, enhanced activity respective to the ligand against Pseudomonas aeruginosa. Costz did not show mutagenic properties with the Ames test. In the Allium cepa test the complex showed cytotoxic properties but not genotoxic ones. These results may be auspicious, however, further biological studies are needed to consider the complex Costz as a possible drug in the future.

Synthesis, characterization, microbiological evaluation, genotoxicity and synergism tests of new nano silver complexes with sulfamoxole: X-ray diffraction of [Ag2(SMX)2]·DMSO.

The synthesis and microbiological evaluation of two new Ag(I) complexes with sulfamoxole (SMX), [Ag2(SMX)2]·H2O and [Ag4(SCN)3(SMX)]·H2O are described. Both were characterized by elemental analysis, thermogravimetry, powder and single crystal X-ray diffraction, NMR, Raman and experimental and theoretical IR spectroscopies. Their antibacterial and antifungal properties were evaluated by agar and broth dilution assays, respectively. In addition, synergism tests for Pseudomonas aeruginosa were performed, and genotoxicity studies were carried out employing the Allium cepa test. Both complexes displayed good activity against Escherichia coli, Staphylococcus aureus, P. aeruginosa, and 10 fungi strains, with lower minimum inhibitory concentrations (MICs) than that of free SMX in all cases. The nanometrical crystallite particle size determined from XRPD, DLS and TEM might explain the good microbiological activity in spite of the low solubility of both complexes. The fractional inhibitory concentration (FIC) calculated from the P. aeruginosa test data indicated that the activity of the complexes is not due to synergism of the free components in the concentration ratios studied. Moreover, none of the complexes displayed cytotoxic effects on onions in the concentration range tested, and chromosome aberrations were not observed.

Antibacterial, antifungal, phytotoxic, and genotoxic properties of two complexes of Ag(I) with sulfachloropyridazine (SCP): X-ray diffraction of [Ag(SCP)]n.

We report the synthesis, characterization, antibacterial and antifungal activities, phytotoxicity, and genotoxicity of two new complexes of silver(I) with sulfachloropyridazine (SCP), one of which is heteroleptic with SCP and SCN(-) ligands (Ag-SCP-SCN), the other of which is homoleptic (Ag-SCP); furthermore, the crystal structure of the homoleptic complex is disclosed. The heterocyclic N atom nearest to the Cl atom and the N(sulfonamide) atom could be coordination sites for the silver ion in the Ag-SCP-SCN complex. The Ag-SCP complex is a polymeric compound with metal-metal bonds, and the heterocyclic and sulfonamide N atoms are points of coordination for Ag(I) . Both complexes showed activity against all the tested bacteria, and in the cases of Escherichia coli and Pseudomonas aeruginosa, the action was better than that of SCP. In all cases, both silver-SCP complexes showed better antifungal activity than SCP, which was inactive against the tested fungi. Notably, the activity against P. aeruginosa, a nosocomial multidrug-resistant pathogen, was better than that of the reference antibiotic cefotaxim. Both silver-sulfa complexes displayed moderate activity against the tested yeast, especially for C. neoformans, which is an important fact considering the incidence of cryptococcosis, mainly in immune-deficient patients. No chromosomal aberrations were observed with the Allium cepa test, which is auspicious for further study of these complexes as potential drugs.

Synthesis, characterization and antimicrobial properties of a Co(II)-phthalylsulfathiazolate complex.

The reaction between phthalylsulfathiazole (H(2)PST), in alkaline aqueous solution, and cobalt(II) nitrate led to a pink solid, [Co(PST)(H(2)O)(4)] (1), which was characterized by elemental and thermogravimetric analysis; FT-IR, Raman and diffuse reflectance spectra. Spectroscopic data reveal that the ligand would be doubly deprotonated and that the Co(II) ion environment is a distorted octahedral one. (1) showed antibacterial activity similar to the ligand.