Metalloantibiotics and antibiotic mimics - an overview
ABSTRACT The metal cores of metalloantibiotics offer a unique prospect to probe their structure and function at functional groups that can readily be distinguished from the surrounding environment. Metalloantibiotics interact with DNA, RNA, proteins, receptors and lipids, making them very unique and specific. Metal contamination potentially contributes to the maintenance and spread of antibiotic resistance factors. Certain metal ions binding with antibiotics (bleomycin, histatin, and bacitracin) and the Alzheimer’s disease-related β-amyloid peptide exhibited specific biological activities and chemical reactivities. Bismuth-fluoroquinolone complexes have the potential to be developed as drugs against H. pylori related ailments. Antibiotics metal complexes as well as mixed antibiotics metal complexes were found more effective as chemotherapy agents than their parent antibiotics. The addition of vitamin C markedly enhanced the activities of both pomegranates/Fe (II) and pomegranates /Cu (II) combinations against S. aureus.
- SourceAvailable from: Ahlam Abdulghani[Show abstract] [Hide abstract]
ABSTRACT: UV-visible and atomic spectrophotometry and HPLC techniques were applied for the determination of tetracycline (TC) in pharmaceutical preparations via complexation of the drug with Au(III) and Hg(II) ions in solutions. The mole ratio of TC to metal ions was 1 : 1. Maximum peak absorption at λ 425 and 320 nm for the two ions, respectively, was optimized at heating temperature 75°C for 15 minutes at pH = 4 followed by the extraction with ethyl acetate. The percentage of extraction and stability constants for the two complexes was 95.247, 95.335% and 2.518 × 10(4), 1.162 × 10(5) M(-1), respectively. HPLC method was applied without extraction process. The analytical data obtained from direct calibration curves of UV-visible absorption, FAAS, and HPLC for Au(III) complexes were recovery (100.78, 104.85, and 101.777%, resp.); detection limits (0.7403, 0.0997, and 2.647 μ g/ml, resp.); linearity (5-70, 5-30, and 10-150 μ g/ml, resp.), and correlation coefficient (0.9991, 0.9967, and 0.9986, resp.). The analytical data obtained from direct calibration curves for Hg(II) complexes by UV-visible spectrophotometry and HPLC were recovery (100.95 and 102.000%, resp.); detection limits (0.5867 and 2.532 μ g/ml, resp.); linearity (5-70 and 10-150 μ g/ml, resp.); and correlation coefficients (0.9989 and 0.9997, resp.).International Journal of Analytical Chemistry 01/2013; 2013:305124. · 0.90 Impact Factor
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ABSTRACT: Biological synthesis of nanoparticles is a growing innovative approach that is relatively cheaper and more environmentally friendly than current physicochemical processes. Among various microorganisms, fungi have been found to be comparatively more efficient in the synthesis of nanomaterials. In this research work, extracellular mycosynthesis of silver nanoparticles (AgNPs) was probed by reacting the precursor salt of silver nitrate (AgNO3) with culture filtrate of Aspergillus flavus. Initially, the mycosynthesis was regularly monitored by ultraviolet-visible spectroscopy, which showed AgNP peaks of around 400-470 nm. X-ray diffraction spectra revealed peaks of different intensities with respect to angle of diffractions (2θ) corresponding to varying configurations of AgNPs. Transmission electron micrographs further confirmed the formation of AgNPs in size ranging from 5-30 nm. Combined and individual antibacterial activities of the five conventional antibiotics and AgNPs were investigated against eight different multidrug-resistant bacterial species using the Kirby-Bauer disk-diffusion method. The decreasing order of antibacterial activity (zone of inhibition in mm) of antibiotics, AgNPs, and their conjugates against bacterial group (average) was; ciprofloxacin + AgNPs (23) . imipenem + AgNPs (21) > gentamycin + AgNPs (19) > vancomycin + AgNPs (16) > AgNPs (15) . imipenem (14) > trimethoprim + AgNPs (14) > ciprofloxacin (13) > gentamycin (11) > vancomycin (4) > trimethoprim (0). Overall, the synergistic effect of antibiotics and nanoparticles resulted in a 0.2-7.0 (average, 2.8) fold-area increase in antibacterial activity, which clearly revealed that nanoparticles can be effectively used in combination with antibiotics in order to improve their efficacy against various pathogenic microbes.International Journal of Nanomedicine 01/2013; 8:3187-95. · 4.20 Impact Factor