Solution and biological behaviour of enrofloxacin metalloantibiotics: A route to counteract bacterial resistance (original) (raw)
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Mixed ligand complexes of metals (Fe(III), Co(II), Cu(II), Ni(II) and Zn(II)) with the Schiff bases of L1 and HL2 (L1 - obtained through the condensation of 4-aminoantipyrine with furfuraldehyde and HL2 – derived from 2-aminophenol and vanillin) were synthesized. They were characterized using analytical and spectral techniques. Cyclic voltammogram of complexes in DMSO solution at 300 K was recorded and their salient features were summarized. The X-band ESR spectrum of the copper complex in DMSO solution at 300 and 77 K was recorded. All the synthesized metal complexes were screened for their in vitro antimicrobial activity against of bacteria and fungi by disc diffusion method. Comparative study of inhibition values of the Schiff bases and their complexes indicate that the complexes exhibit higher antimicrobial activity than the free ligands. The interaction of metal complexes with CT-DNA was investigated by UV-Vis., cyclic voltammetry, viscosity and thermal denaturation studies. The nuclease activities of the complexes were assayed on pUC19 DNA using gel electrophoreses in the presence of H2O2. All the metal complexes cleave the pUC19 DNA in presence of H2O2. The solvatochromic behaviour of complexes was discussed using UV-Vis., spectrophotometry in various solvents. Superoxide dismutase activity of these complexes has also been studied.
The Scope of Metal Complexes in Drug Design - a Review
INDIAN DRUGS, 2012
A significantly rising interest in the design of metal compounds as drugs and diagnostic agents is currently observed in the area of scientific inquiry, appropriately termed medicinal inorganic chemistry. Investigations in this area focus mostly on the speciation of metal species in biological media based on possible interactions of these metal ions with diverse biomolecules, in an effort to contribute to future development of new therapeutics or diagnostic agents. Metallopharmaceuticals used as anticancer agents, metal-mediated antibiotics, antibacterials, antivirals, antiparasitics, antiarthritics, antidiabetics and radio-sensitizing agents appear in therapeutic medicinal inorganic chemistry. The medicinal uses and applications of metals and metal complexes are of increasing clinical and commercial importance.
Antimicrobial Agents Based on Metal Complexes: Present Situation and Future Prospects
International Journal of Biomaterials
The rise in antimicrobial resistance is a cause of serious concern since the ages. Therefore, a dire need to explore new antimicrobial entities that can combat against the increasing threat of antibiotic resistance is realized. Studies have shown that the activity of the strongest antibiotics has reduced drastically against many microbes such as microfungi and bacteria (Gram-positive and Gram-negative). A ray of hope, however, was witnessed in early 1940s with the development of new drug discovery and use of metal complexes as antibiotics. Many new metal-based drugs were developed from the metal complexes which are potentially active against a number of ailments such as cancer, malaria, and neurodegenerative diseases. Therefore, this review is an attempt to describe the present scenario and future development of metal complexes as antibiotics against wide array of microbes.
Metal Complexes as a Promising Source for New Antibiotics
There is a dire need for new classes of antimicrobial compounds to combat the growing threat of widespread antibiotic resistance. With a currently very scarce drug pipeline, consisting mostly of derivatives of known antibiotics, new classes of antibiotics are urgently required. Antibiotic compounds are notorious for not having very “drug-like” chemical structures. Metal complexes are currently in clinical development for the treatment of cancer, malaria and neurodegenerative diseases. However, only little attention has been paid to their application as potential antimicrobial compounds. We report the evaluation of 906 metal-containing compounds that have been screened by the Community for Open Antimicrobial Drug Discovery (CO-ADD) for antimicrobial activity. Metal-bearing compounds display a significantly higher hit-rate (9.9%) when compared to the purely organic molecules (0.87%) in the CO-ADD database. Out of 906 compounds, 88 show activity against at least one of the tested strai...
Macrocyclic ligands are polydentate ligands containing donor atoms either incorporated or attached to cyclic backbone and showed significance in various biological studies. Tetraaza macrocyclic complexes of transition metals, Ni(II), Cu(II), Fe(III), and Mn(II) were synthesized in methanolic media using template method. These complexes were non-hygroscopic and consist of crystalline solids. Structural identification of these complexes was done using analytical techniques UV-Vis and IR Spectroscopy. The antibacterial activities of macrocyclic complexes (1-6) were screened against both Gram-negative bacteria (Escherichia coli and Vibrio cholerae) and Gram-positive bacteria (Bacillus subtilis and Staphylococcus aureus). In the present study we have reported that these synthesized complexes showed slight antibacterial activity except macrocyclic complex (6) which showed moderate antibacterial activity.
Objective: The appearance of resistant bacteria reduces the efficiency of antimicrobial therapies, thereby increasing the need for more efficient drugs for infections treatment. Many studies have shown an enhance in antimicrobial activity after the interaction of many agents with metal ions. Complexes of the metal ions with ligands which are polydentate have been the theme of demanding research as they have interesting spectral, magnetic properties and a miscellaneous spectrum of biological activities. Methods: New isoniazid based compounds and their transition metal complexes (cobalt (II), copper (II), nickel (II) and zinc (II)) were produced using microwave synthesis technique. The All compounds which were synthesized (free ligand and their metal complexes) were fully characterized by many spectroscopic techniques (FT-IR spectra, UV/visible electronic spectra, mass spectra and 13 C NMR and 1 H NMR spectra). In addition, CHN, XRFA, AAS merged with other spectroscopic data were utilized to allocate the precise ligand to metal ratio and geometry. The synthesized ligands and their complexes were tested for in vitro antimicrobial activity against Candida albicans (ATCC 10231), Aspergillus niger (ATCC 16404), Escherichia coli (ATCC 25922), and Staphylococcus aureus (ATCC 29213) by using agar-well diffusion. Results: Based on analytical and spectroscopic findings, the ligands proceed as a coordinate and monoanionic tridentate throughout phenolic oxygen, azomethine nitrogen, and carbonyl oxygen. New complexes of n-isonicotinamido-2-hydroxy-5-methoxy benzalaldimine with Cu(II), Co(II) and Zn(II), having a formula of the type [M (L) 2 ].nH 2 O, (M = Co(II), n = 1.5; Zn(II), n = 0; Cu(II), n = 6) and with Ni(II), featuring a formula of the type [M (L) (H 2 O)] (ac).nH 2 O, (M = Ni(II), n = 0, ac = CH 3 COO¯) were obtained. Accordingly, octahedral geometries were determined to Zinc(II), Cobalt(II) and Copper(II) complexes and geometry of the tetrahedral was allocate to the Ni(II) complex. Conclusion: Biological findings indicate that complexation may increase or decrease the antimicrobial activity of some complexes. This could be endorsed to an increase of complexes lipophilicity in comparison to the parent ligand.