scholarly journals Novel Zinc(II) Complexes of Heterocyclic Ligands as Antimicrobial Agents: Synthesis, Characterisation, and Antimicrobial Studies

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Ramesh S. Yamgar ◽  
Y. Nivid ◽  
Satish Nalawade ◽  
Mustapha Mandewale ◽  
R. G. Atram ◽  
...  

The synthesis and antimicrobial activity of novel Zn(II) metal complexes derived from three novel heterocyclic Schiff base ligands 8-[(Z)-{[3-(N-methylamino)propyl]imino}methyl]-7-hydroxy-4-methyl-2H-chromen-2-one, 2-[(E)-{[4-(1H-1,2,4-triazol-1-ylmethyl)phenyl]imino}methyl]phenol, and (4S)-4-{4-[(E)-(2-hydroxybenzylidene)amino]benzyl}-1,3-oxazolidin-2-one have been described. These Schiff base ligands and metal complexes are characterised by spectroscopic techniques. According to these data, we propose an octahedral geometry to all the metal complexes. Antimicrobial activity of the Schiff base ligand and its metal complexes was studied against Gram negative bacteria:E. coliandPseudomonas fluorescens, Gram positive bacteria:Staphylococcus aureus,and also against fungi, that is,C. albicansandA. niger. Some of the metal complexes show significant antifungal activity (MIC < 0.2 μg/mL). The “in vitro” data has identified [Zn(NMAPIMHMC)2]·2H2O, [Zn(TMPIMP)2]·2H2O, and [Zn(HBABO)2]·2H2O as potential therapeutic antifungal agents againstC. albicansandA. niger.

2010 ◽  
Vol 2010 ◽  
pp. 1-7 ◽  
Author(s):  
Ramasamy Jayarajan ◽  
Gnanasambandam Vasuki ◽  
Pillutla Sambasiva Rao

Synthesis, characterization, and antimicrobial activity of tridentate Schiffbase ligands containing pyrazolone moiety (3a and 3b) and their transition metal complexes of VO(II), Cu(II), Fe(III), and Co(II) 4a–h have been investigated. The complexes show enhanced antibacterial activity against S. aureus, E. coli, and S. typhi and antifungal activity against C. albicans, Rhizopus sp., and A. niger compared to the ligands.


2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
K. R. Joshi ◽  
A. J. Rojivadiya ◽  
J. H. Pandya

Two new series of copper(II) and nickel(II) complexes with two new Schiff base ligands 2-((2,4-dimethylphenylimino)methyl)-6-methoxy-4-nitrophenol and 2-((3,4-difluorophenylimino)methyl)-6-methoxy-4-nitrophenol have been prepared. The Schiff base ligands were synthesized by the condensation of 2-hydroxy-3-methoxy-5-nitrobenzaldehyde with 2,4-dimethylaniline or 3,4-difluoroaniline. The ligands and their metal complexes have been characterized by IR, 1H NMR, mass and electronic spectra and TG analysis. The Schiff base ligands and their metal complexes were tested for antimicrobial activity against Gram positive bacteria Staphylococcus aureus, and Streptococcus pyogenes and Gram negative bacteria Escherichia coli, and Pseudomonas aeruginosa and fungus Candida albicans, Aspergillus niger, and Aspergillus clavatus using Broth Dilution Method.


2012 ◽  
Vol 9 (3) ◽  
pp. 1113-1121 ◽  
Author(s):  
A. P. Mishra ◽  
A. Tiwari ◽  
S. K. Gupta ◽  
Rajendra Jain

Some new Schiff base metal complexes of Co(II), Ni(II) and Cu(II) derived from 3-chloro-4-fluoroaniline (HL1) and 4-fluoroaniline (HL2) with 2-thiophenecarboxaldehyde have been synthesized and characterized by elemental analysis, FT-IR, FAB-mass, molar conductance, electronic spectra, ESR and magnetic susceptibility. The complexes exhibit coordination number 4 or 6. The complexes are colored and stable in air. Analytical data revealed that all the complexes exhibited 1:2 (metal: ligand) ratio. FAB-mass data show degradation pattern of the complexes. The Schiff base and metal complexes show a good activity against the bacteria;B. subtilis,E. coliandS. aureusand fungiA. niger,A. flavusandC. albicans. The antimicrobial results also indicate that the metal complexes are better antimicrobial agents as compared to the Schiff bases.


Author(s):  
Abu- Safieh Rana ◽  
Muhi- Eldeen Zuhair ◽  
Alsarahni Aseel ◽  
Al-Kaissi Elham

A new series of 7-methoxy-2-[4-(t-amino-1-yl)oxy]-naphthalene derivatives; 7-methoxy-2-{[4-(2-methylpiperidine)but-2-yn-1-yl]oxy}-naphthalene (RZ2), 7-methoxy-2-{[4-(2,6-dimethylpiperidine)but-2-yn-1-yl]oxy}-naphthalene (RZ3), 7-methoxy-2{[4-(piperidine)but-2-yn-1-yl]oxy}-naphthalene (RZ4), 7-methoxy-2-{[4-(pyrrolidine)but-2-yn-1-yl]oxy}-naphthalene (RZ5), 7-methoxy-2-{[4-(N-methylpiperazine)but-2-yn-1-yl]oxy}-naphthalene (RZ6), 7-methoxy -2-{[4-(hexamethyleneimine)but-2-yn-1-yl]oxy}-naphthalene (RZ7) were synthesized and screened in vitro as potential antimicrobial agents. Antimicrobial activity were evaluated by measuring the minimum inhibitory and bactericidal/fungicidal concentration (MIC, MBC and MFC). RZ2, RZ5, RZ6 and RZ7 showed the highest antimicrobial activity against S. aureus with MIC value 62.5 µg/ml, compounds RZ2, RZ4, RZ5, and RZ7 have the highest antimicrobial activity against B. subtilis with MIC vale 62.5 µg/ml, RZ3, RZ6 have the same antimicrobial activity with MIC value 125µg/ml, compounds. RZ4, RZ5, RZ6 and RZ7 have the highest antimicrobial activity against E. coli with MIC value 125 µg/ml, all compounds have the same MIC value against P. aeruginosa (125 µg/ml). RZ2, RZ4, RZ5, RZ6, RZ7 showed the highest antifungal activity with MIC of 62.5 µg/ml. In conclusion, the synthesized compounds showed good antimicrobial activity and promising potency against gram positive bacteria, gram negative bacteria and fungi.


2019 ◽  
Vol 15 (1) ◽  
pp. 114-119 ◽  
Author(s):  
Rakesh Kumar ◽  
Shailendra Patil

Background:Diseases caused by microbial infections are very common worldwide. Although the search of innovative antimicrobial agents is the current focus for the researchers, the treatment of infectious diseases remains an important public health issue and a challenging problem in front of medicinal chemist.Methods:A series of 2-(4-hydroxyphenyl)-3-(4-(4-nitrophenyl) thiazol-2-yl)thiazolidin-4-one derivatives (T1-T10) was designed and synthesized. All the titled compounds were evaluated for their antimicrobial potential. Antimicrobial activity was performed by tube dilution methods against Gram negative Escherichia coli MTCC 443 (E. Coli), Gram positive bacteria: Staphylococcus aureus MTCC 3160 (S. aureus) and Bacillus subtilis MTCC 441 (B. Subtilis), and fungal strains: Aspergillus niger MTCC 281 (A. niger) and Candida albicans MTCC 227 (C. albicans).Results:Among the synthesized derivatives, compounds 2, 4 and 10 were found to be most active antimicrobial agents.Conclusion:In conclusion, a series of 2-(phenyl)-3-(4-(phenyl)thiazol-2-yl)thiazolidin-4-ones have been designed and synthesized. All the titled compounds were evaluated for their in vitro antimicrobial activity against five representative microorganisms. The results of antimicrobial study indicated that the presence of nitro and chloro groups in aromatic ring improved antibacterial activity, whereas the presence of hydroxy group improved antifungal activity of substituted 4-thiazolidinone derivatives.


2012 ◽  
Vol 9 (4) ◽  
pp. 2516-2523 ◽  
Author(s):  
Matangi Sunitha ◽  
Pragathi Jogi ◽  
Bathini Ushaiah ◽  
C. Gyana Kumari

Metal complexes of Ni(II), Co(II), Cu(II), Mn(II) and Zn(II) VO(IV) with a Schiff base derived from 3-Ethoxy Salicylaldehyde and 2-(2-amino-phenyl)1-H-Benzimidazol(2-[(Z)-{(2-(1H-benzimidazole-2yl)phenyl] imino} methyl]-6-ethoxy phenol-BMEP) were synthesized successfully. The resulting complexes were characterized by elemental analysis, magnetic moment measurements, conductivity measurements, IR, UV-VIS, 1H NMR, mass spectra and ESR spectral studies. According to these data, we propose an octahedral geometry to all the metal complexes. Antimicrobial activity of the ligand and its metal complexes were studied against two gram negative bacteria:E. coli, Pseudomonas flourescenceand two gram positive bacteria:Bacillus subitilis, Staphylococcus aureus. The activity data show that the metal complexes are more potent than the free ligand.


Author(s):  
Fatimah A. Abdulsayid ◽  
Hamad M. Adress Hasan ◽  
Roaa A. Bouagila

Four metal complexes of Co(II), Pb(II),  Ni(II) and Fe(II) ions with a Schiff base derived from (3-methoxy-4-hydroxy-benzaldehyde with leucine) have been synthesized and characterized using several physical techniques, in particular; molar conductance measurements, colour, melting point,  infrared and electronic spectra. The molar conductance values reveal a non-electrolytic nature. The infrared spectral data display the coordination behaviour of the Schiff base toward Co(ll) ,pb(ll) ,Ni(ll) and Fe(ll) ions. The electronic absorption spectra of the Schiff base and its complexes show π→π* (phenyl ring) and, n→π* (HC=N) and the expected geometrical structure for the prepared complexes. The Schiff base and its complexes were tested for antimicrobial activity against gram-positive bacteria; Staphylococcus aurous; E. Coli and Klebsiella, in addition Rizopus as fungal. The effect of the Schiff base leucine complex on bacteria was recorded only against Staphylococcus aureus and Escherichia coli.


2009 ◽  
Vol 6 (3) ◽  
pp. 615-624 ◽  
Author(s):  
K. Siddappa ◽  
K. Mallikarjun ◽  
Tukaram Reddy ◽  
M. Mallikarjun ◽  
C. V. Reddy ◽  
...  

A new complexes of the type ML, MʹL and M″L [where M=Cu(II), Co(II), Ni(II) and Mn(II), Mʹ=Fe(III) and M″=Zn(II), Cd(II) and Hg(II) and L=N1-[(1E)-1-(2-hydroxyphenyl)ethylidene]-2-oxo-2H-chromene- 3-carbohydrazide (HL)] Schiff base have been synthesized and characterized by elemental analysis, magnetic susceptibility, molar conductance, IR,1H NMR, UV-Visible and ESR data. The studies indicate the HL acts as doubly monodentate bridge for metal ions and form mononuclear complexes. The complexes Ni(II), Co(II), Cu(II) Mn(II) and Fe(III) complexes are found to be octahedral, where as Zn(II), Cd(II) and Hg(II) complexes are four coordinated with tetrahedral geometry. The synthesized ligand and its metal complexes were screened for their antimicrobial activity.


Author(s):  
AMAL M ALOSAIMI ◽  
INES EL MANNOUBI ◽  
SAMI A ZABIN

Objective: This work aimed at synthesizing tridentates asymmetrical Schiff base ligands containing sulfur atom and using them for preparing metal complexes with the iron triad metals. The prepared compounds were assayed in vitro for antimicrobial potential and in vivo molluscicidal activity. Methods: The unsymmetrical tridentate Schiff bases (SL1, SL2, and SL3) were prepared using 2-aminothiophenol as primary amine and condensed with 2-carboxybenzaldehyde, 2-hydroxy-1-naphthaldehyde, and 7-formyl-8-hydroxyquinoline. These ligands were used in preparing metal complexes with iron triad metals. The synthesized Schiff base ligands and their corresponding metal complexes were characterized and their proposed structures were confirmed using different physical and spectroscopic analytical techniques. All ligands and their corresponding metal complexes were assayed against different bacterial and fungal strains using the agar disk-diffusion technique. The molluscicidal activity was performed according to the standard reported methods as cited in the literature and by observing the toxicity and lethal dose according to the WHO guidelines. Results: The synthesized ligands behave as tridentate (NOS) ligands and form mononuclear complexes with the general formula [M(SL)2] with an octahedral geometry around the central metal ion. Metal complexes were non-electrolytic in nature. The in vitro antibacterial and antifungal examination results showed weak activity of the ligands, and there was enhanced activity with the complexes. The in vivo molluscicidal activity of the tested compounds showed good activity. Conclusion: The targeted compounds were prepared successfully, characterized, and showed some biological activity but lower than the standard reference drugs.


Molecules ◽  
2020 ◽  
Vol 25 (12) ◽  
pp. 2766 ◽  
Author(s):  
Heba E. Hashem ◽  
Abd El-Galil E. Amr ◽  
Eman S. Nossier ◽  
Elsayed A. Elsayed ◽  
Eman M. Azmy

To develop new antimicrobial agents, a series of novel thiourea derivatives incorporated with different moieties 2–13 was designed and synthesized and their biological activities were evaluated. Compounds 7a, 7b and 8 exhibited excellent antimicrobial activity against all Gram-positive and Gram-negative bacteria, and the fungal Aspergillus flavus with minimum inhibitory concentration (MIC) values ranged from 0.95 ± 0.22 to 3.25 ± 1.00 μg/mL. Furthermore, cytotoxicity studies against MCF-7 cells revealed that compounds 7a and 7b were the most potent with IC50 values of 10.17 ± 0.65 and 11.59 ± 0.59 μM, respectively. On the other hand, the tested compounds were less toxic against normal kidney epithelial cell lines (Vero cells). The in vitro enzyme inhibition assay of 8 displayed excellent inhibitory activity against Escherichia coli DNA B gyrase and moderate one against E. coli Topoisomerase IV (IC50 = 0.33 ± 1.25 and 19.72 ± 1.00 µM, respectively) in comparison with novobiocin (IC50 values 0.28 ± 1.45 and 10.65 ± 1.02 µM, respectively). Finally, the molecular docking was done to position compound 8 into the E. coli DNA B and Topoisomerase IV active pockets to explore the probable binding conformation. In summary, compound 8 may serve as a potential dual E. coli DNA B and Topoisomerase IV inhibitor.


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