Norfloxacin Zn(II)-based complexes: acid base ionization constant determination, DNA and albumin binding properties and the biological effect against Trypanosoma cruzi
| Autor: | D. G. J. Batista, Ligiane R. Gouvea, Maria de Nazaré Correia Soeiro, Darliane A. Martins, Paulo J.S. Barbeira, Letícia R. Teixeira, Sonia R.W. Louro |
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| Rok vydání: | 2013 |
| Předmět: |
Stereochemistry
Trypanosoma cruzi Antiprotozoal Agents Medicinal chemistry Fluorescence General Biochemistry Genetics and Molecular Biology Fluorescence spectroscopy Acid dissociation constant Biomaterials Structure-Activity Relationship chemistry.chemical_compound Parasitic Sensitivity Tests Organometallic Compounds Animals Bovine serum albumin Binding Sites Quenching (fluorescence) Dose-Response Relationship Drug biology Metals and Alloys Tryptophan Serum Albumin Bovine DNA Hydrogen-Ion Concentration Ligand (biochemistry) Zinc chemistry biology.protein Cattle Titration General Agricultural and Biological Sciences Norfloxacin |
| Zdroj: | BioMetals. 26:813-825 |
| ISSN: | 1572-8773 0966-0844 |
| DOI: | 10.1007/s10534-013-9661-z |
| Popis: | Zn(II) complexes with norfloxacin (NOR) in the absence or in the presence of 1,10-phenanthroline (phen) were obtained and characterized. In both complexes, the ligand NOR was coordinated through a keto and a carboxyl oxygen. Tetrahedral and octahedral geometries were proposed for [ZnCl2(NOR)]·H2O (1) and [ZnCl2(NOR)(phen)]·2H2O (2), respectively. Since the biological activity of the chemicals depends on the pH value, pH titrations of the Zn(II) complexes were performed. UV spectroscopic studies of the interaction of the complexes with calf-thymus DNA (CT DNA) have suggested that they can bind to CT DNA with moderate affinity in an intercalative mode. The interactions between the Zn(II) complexes and bovine serum albumin (BSA) were investigated by steady-state and time-resolved fluorescence spectroscopy at pH 7.4. The experimental data showed static quenching of BSA fluorescence, indicating that both complexes bind to BSA. A modified Stern–Volmer plot for the quenching by complex 2 demonstrated preferential binding near one of the two tryptophan residues of BSA. The binding constants obtained (K b ) showed that BSA had a two orders of magnitude higher affinity for complex 2 than for 1. The results also showed that the affinity of both complexes for BSA was much higher than for DNA. This preferential interaction with protein sites could be important to their biological mechanisms of action. The analysis in vitro of the Zn(II) complexes and corresponding ligand were assayed against Trypanosoma cruzi, the causative agent of Chagas disease and the data showed that complex 2 was the most active against bloodstream trypomastigotes. |
| Databáze: | OpenAIRE |
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