scholarly journals Antibacterial Co(II), Cu(II), Ni(II) and Zn(II) Complexes of Thiadiazoles Schiff Bases

2001 ◽  
Vol 8 (2) ◽  
pp. 95-101 ◽  
Author(s):  
Zahid H. Chohan ◽  
Maimoon F. Jaffery ◽  
Claudiu T. Supuran

Schiff bases were obtained by condensation of 2-amino-l,3,4-thiadiazole with 5-substituted-salicylaldehydes which were further used to obtain complexes of the type [M(L)2]Cl2, where M=Co(II), Cu(II), Ni(II) or Zn(II). The new compounds described here have been characterized by physical, spectral and analytical data, and have been screened for antibacterial activity against several bacterial strains such as Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa. The antibacterial potency of these Schiff bases increased upon chelation/complexation, against the tested bacterial species, opening new aproaches in the fight against antibiotic resistant strains.

1998 ◽  
Vol 5 (5) ◽  
pp. 267-274 ◽  
Author(s):  
Zahid H. Chohan ◽  
Marapaka Praveen ◽  
Syed K. A. Sherazi

Biologically active complexes of Co(II), Ni(II), Cu(II) and Zn(II) with novel ONO, NNO and SNO donor pyrazinoylhydrazine-derived compounds have been prepared and characterized on the basis of analytical data and various physicochemical studies. Distorted octahedral structures for all the complexes have been proposed. The synthesized ligands and their complexes have been screened for their antibacterial activity against bacterial species Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Klebsiella pneumonae. The activity data show the metal complexes to be more active than the parent free ligands against one or more bacterial species.


2002 ◽  
Vol 8 (5) ◽  
pp. 263-267 ◽  
Author(s):  
Zahid H. Chohan ◽  
Humayun Pervez ◽  
Abdul Rauf ◽  
Claudiu T. Supuran

A condensation reaction of 2-amino-1,3,4-thiadiazole with 2-pyrrolecarboxaldehyde to form tridentate NNN donor Schiff base has been performed. The prepared Schiff base was further used for the formation of metal complexes having stoichiometry [M(L)2]Xn , where M=Cu(II) or Zn(II), L=N-(2-pyrrolylmethylene)-2-amino-1,3,4-thiadiazole, X=SO42− , NO3− , C2O42− or CH3CO2− and n=1 or 2. The new compounds described here have been characterized by their physical, spectral and analytical data, and have been screened against several bacterial strains such as Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa. The antibacterial potency of the Schiff base increased upon chelation/complexation, having the same metal ion (cation) but different anions opening up a novel approach in finding new ways to fight against antibiotic resistant strains.


2001 ◽  
Vol 8 (3) ◽  
pp. 137-143 ◽  
Author(s):  
Zahid H. Chohan ◽  
Asifa Munawar ◽  
Claudiu T. Supuran

Some novel transition metal [Co(II), Cu(II), Ni(II) and Zn(II)] complexes of substituted pyridine Schiff-bases have been prepared and characterized by physical, spectral and analytical data. The synthesized Schiff-bases act as deprotonated tridentate for the complexation reaction with Co(II), Ni(II) and Zn(II) ions. The new compounds, possessing the general formula [M(L)2] where [M=Co(II), Cu(II), Ni(II) and Zn(II) and HL=HL1, HL2, HL3 and HL4] show an octahedral geometry. In order to evaluate the effect of metal ions upon chelation, the Schiff bases and their complexes have been screened for antibacterial activity against the strains such as Escherichia coli,Staphylococcus aureus, and Pseudomonas aeruginosa. The complexed Schiff bases have shown to be more antibacterial against one more bacterial species as compared to uncomplexed Schiff-bases.


2000 ◽  
Vol 7 (5) ◽  
pp. 265-269 ◽  
Author(s):  
Zahid H. Chohan ◽  
Maimoon F. Jaffery

Some Co(II), Cu(II), Ni(II) and Zn(II) complexes of antibacterial drug cephradine have been prepared and characterized by their physical, spectral and analytical data. Cephradine acts as bidentate and the complexes have compositions, [M(L)2X2] where [M = Co(II), Ni(II) and Zn(II), L = cephradine and X = Cl2] showing octahedral geometry, and [M(L)2] where [M = Cu(II), L = cephradine] showing square planar geometry. In order to evaluate the effect of metal ions upon chelation, eephradine and its complexes have been screened for their antibacterial activity against bacterial strains, Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa.


2002 ◽  
Vol 8 (6) ◽  
pp. 323-327 ◽  
Author(s):  
Zahid H. Chohan

Co(II) and Ni(II) complexes Schiff base, N-(2-thienylmethylene)-2-aminothiadiazole have been prepared and characterized by their physical, spectral and analytical data. The title Schiff-base acts as NNS donor tridentate during the complexation reaction with these metal ions having a composition, [M(L)2]Xn where M=Co(II) or Ni(II), L=, X=NO3− , SO42− , C2O42− or CH3CO2− and n=1 or 2 and show an octahedral geometry. In order to evaluate the effect anions upon chelation, the Schiff-base and its new complexes have been screened for their antibacterial activity against bacterial strains e.g., Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa.


2011 ◽  
Vol 8 (1) ◽  
pp. 212-216 ◽  
Author(s):  
Mohamed N. Ibrahim ◽  
Salaheddin A. I. Sharif ◽  
Ahmad N. EL-Tajory ◽  
Asma A. Elamari

Schiff basesp-hydroxybenzylidene-2-carboxyaniline,p-nitrobenz-ylidene-2-carboxyaniline,p-(N, N-dimethyl)aminobenzylidene-2-carboxyaniline,N-(4-hydroxybezylidene)-benzene-1,2-diamine,N--(4-nitrobezylidene)benzene-1,2-diamine,N-(4-(N, N-dimethylaminobezylidene)benzene-1,2-diamine,N-(4-(N,N-dimethylamino)benzylidene)naphthalen-1-amine,N-(4-nitrobenzylidene)naphthalen-1-amine,N--(4-chlorobenzylidene)naphthalen-1-amine,sodium-4-(4-(N,N-dimethyl amino)benzylideneamino)naphthalene-1-sulfonate,sodium -4-(4-nitrobenzylidene-amino)naphthalene-1-sulfonate and sodium-4-(4-chlorobenzylideneamino) naphthalene-1-sulfonate obtained by condensation of aniline and naphthyl-amine derivatives with some aromatic aldehydes were characterized by physical and spectral methods. The biological activity of these products were as antibacterial agents against three species of human pathogenic bacteria such asEscherichia coli, Staphylococcus aureusandKlebsiella sp. Nearly 50% of these compounds showed reasonable activity against the bacterial species investigated and we found that the antibacterial activity is dependent on the molecular structure of the compounds.


2018 ◽  
Vol 42 (10) ◽  
pp. 512-514
Author(s):  
Rui-bo Xu ◽  
Xiao-tian Yang ◽  
Hai-nan Li ◽  
Peng-cheng Zhao ◽  
Jiao-jiao Li ◽  
...  

Two new bis-Schiff bases containing a piperazine ring, N,N‘-bis(4-chlorobenzylidene)- and N,N‘-bis(4-cyanobenzylidene)-1,4-bis(3-aminopropyl)piperazine, were prepared by the reaction of N,N‘-bis(3-aminopropyl)piperazine with 4-chloro- and 4-cyanobenzaldehyde, respectively. The dichloro compound was fully identified by X-ray crystallography and it exhibited good antibacterial activity against Escherichia coli, Staphylococcus aureus and Bacillus subtilis.


2021 ◽  
Vol 5 (1) ◽  
pp. 1-9
Author(s):  
Antonio Carlos Pereira de Menezes Filho ◽  
Matheus Vinícius Abadia Ventura ◽  
Carlos Frederico de Souza Castro

Tibouchina granulosa is a species that blooms annually in several regions of Brazil. This species is still little explored in terms of phytocompounds in all organs of this plant, especially the floral organ. Flowers of T. granulosa were collected in the municipality of Rio Verde, Goiás, Brazil, in 2021. The hydroethanolic floral extract was prepared by maceration and qualitative phytochemical (colorimetric reactions and salt formation) and antibacterial analyzes performed and the results expressed in millimeters of inhibition at different concentrations in mg mL-1. Several phytochemical classes were observed with positive results, especially for alkaloids, phenolics, oxylates, saponins, carbohydrates and tannins. As for the bacterial assay, potential antibacterial activity was observed for all bacterial strains tested, except for Salmonella serovar Thyphymurium and serovar Enteritidis. Expressive inhibitions were observed for Enterococcus faecalis > Pseudomonas aeruginosa > Staphylococcus aureus and Escherichia coli at the highest concentrations between 100-50 mg mL-1. The floral extract of Tibouchina granulosa showed phytotherapeutic potential with the presence of several phytochemical groups and expressive antibacterial activity.


Author(s):  
Haribhai Rabari ◽  
Hetal Vankar ◽  
Beenkumar Prajapati

The emergence of multidrug microbial resistance is the main challenges that the modern scientists have so far been facing in the recent era. In this respect, new series of drug classes having potential to give antimicrobial effect have been synthesized. A new series of 5- substituted-1,10 b-dihydroimidazole[1,2-c]quinazoline derivatives 8a-e have been synthesized and screened for antibacterial activity and antifungal activity. Synthesized derivatives were characterized by IR, MASS and 1H-NMR spectroscopy. Synthesized compounds show good activity, which was comparable to the standard drug and it can be useful for the further clinical study. Antibacterial activity was evaluated against four different pathogenic bacterial strains like Staphylococcus aureus, Enterococcus faecalis, Escherichia coli and Pseudo-monas aeruginosa. Among the screened compounds, 8e show good antibacterial activity against Staphylococcus aureus and Escherichia coli with MIC of 50 and 100 μg/ml respectively. Antifungal activity was evaluated  against two strains of fungi. Among the synthesized derivates, compound 8c was emerged out as the potent antifungal compound against Candida albicans and Aspergillus niger with MIC of 25 μg/ml and 75μg/ml respectively. Compound 8e also shows good antifungal activity with MIC of 50 μg/ml against both Candida albicans and Aspergillus niger. The overall results of this study indicated that  synthesized quinazoline derivatives had the potential to act as an antibacterial and antifungal agent, hence further investigation is warranted.


2014 ◽  
Vol 875-877 ◽  
pp. 87-90 ◽  
Author(s):  
Chutimon Satirapipathkul ◽  
Tanakan Chatdum

The film-forming potential of isolate of seed polysaccharide fromCassia fistulawas investigated. Increasing the glycerol concentration in the film increased elongation at break, film solubility and water vapor permeability but decreased tensile strength (TS). The film impregnated with the acetone extract ofAtractylodes lanceawas assessed for inhibition ofEscherichia coliandStaphylococcus aureus. The obtained results showed that the films exhibited antibacterial activity against both bacterial strains. Disc-diffusion assay revealed that the film resulted in a larger inhibition zone around the film onStaphylococcus aureusthan it did onEscherichia coliat the same extract concentrations (0.1 to 0.9 wt %). It can be seen that the film has satisfactory physical and antibacterial properties.


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