Synthesis, molecular modeling, and docking studies of a new pyridazinone-acid hydrazone ligand, and its nano metal complexes. Spectroscopy, thermal analysis, electrical properties, DNA cleavage, antitumor, and antimicrobial activities

2021 ◽  
pp. 131947
Author(s):  
Maha S.A. Abdelrahman ◽  
Fouz M. Omar ◽  
Akila A. Saleh ◽  
Mosad A. El-ghamry
2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
K. Savithri ◽  
B. C. Vasantha Kumar ◽  
H. K. Vivek ◽  
H. D. Revanasiddappa

A bidentate (N- and O-) imine-based ligand (L1) and its metal complexes of types [CuII(L1)2] (C1), [CuII(L1)(Phen)] (C2), [CoIII(L1)2] (C3), and [CoIII(L1)(Phen)] (C4) (L1 = 2-((E)-(6-fluorobenzo[d]thiazol-2-ylimino)methyl)-4-chlorophenol and phen = 1,10-phenanthroline) were synthesized as potential chemotherapeutic drug candidates. The prepared complexes were structurally characterized by spectral techniques (NMR, FT-IR, LC-MS, EPR, and electronic absorption), thermogravimetric analysis (TGA/DTA), magnetic moment, and CHNO elemental analysis. Spectroscopic studies suggested the distorted octahedral structure for all complexes. In vitro bioassay studies include binding and nuclease activities of the ligand and its complexes with target calf thymus- (CT-) DNA were carried out by employing UV-Vis, fluorescence spectroscopy, viscosity, and gel electrophoresis techniques. The extent of binding propensity was determined quantitatively by Kb and Ksv values which revealed a higher binding affinity for C2 and C4 as compared to C1 and C3. In addition, the scavenging superoxide anion free radical (O∙-2) activity of metal complexes was determined by nitroblue tetrazolium (NBT) light reduction assay. Molecular docking studies with DNA and SOD enzyme were also carried out on these compounds. The antimicrobial study has shown that all the compounds are potential antibacterial agents against Gram-negative bacterial strains and better antifungal agents with respect to standard drugs used.


2019 ◽  
Vol 2019 ◽  
pp. 1-14 ◽  
Author(s):  
Dorian Polo-Cerón

This paper reports the synthesis and detailed characterisation of copper(II) and nickel(II) complexes with tridentate thiosemicarbazone ligands H2L1 and H2L2 derived from 2-acetylpyrazine. The ligands and their metal complexes were characterised by different physicochemical techniques, including elemental and thermogravimetric analysis; UV-Vis, IR, 1H-NMR, and 13C-NMR spectroscopy; molar conductance measurements; and mass spectrometry. The crystal structure of the H2L1 ligand was determined by single crystal X-ray diffraction studies. The spectral data showed that the thiosemicarbazone behaves as an NNS tridentate ligand through the nitrogen atoms of the azomethine group and pyrazine ring and the sulphur atom of the thioamide group. Elemental and thermal analyses indicated that the obtained metal complexes had a 1 : 1 stoichiometry (metal-ligand). The interactions between these complexes and calf thymus DNA (CT-DNA) were studied by electronic absorption and viscosity measurements. The activities of these compounds against oxidative DNA cleavage were examined by agarose gel electrophoresis. Cu(II) and Ni(II) complexes can wind DNA strands through groove interactions and promote strand breakage of the plasmid pmCherry under oxidative stress conditions. Moreover, all the complexes could interact more strongly with DNA than could with the free ligands. Finally, the antibacterial activities of the ligands and their complexes were determined by in vitro tests against Gram-positive bacterial strains (S. aureus ATCC 25923, L. monocytogenes ATCC 19115, and B. cereus ATCC 10876) and Gram-negative bacterial strains (E. coli ATCC 25922, S. typhimurium ATCC 14028, and K. pneumoniae ATCC BAA-2146) using the broth microdilution method. The metal complexes showed greater antimicrobial activities than the precursor ligands against some of the microorganisms.


2018 ◽  
Vol 10 (2) ◽  
pp. 135-155 ◽  
Author(s):  
Gloria Antobreh ◽  
Istvan Enyedy ◽  
Aina Westrheim Ravna

2013 ◽  
Vol 172 (3) ◽  
pp. 1407-1432 ◽  
Author(s):  
Madhusudana Pulaganti ◽  
Babajan Banaganapalli ◽  
Chaitanya Mulakayala ◽  
Suresh Kumar Chitta ◽  
Anuradha C. M.

2019 ◽  
Vol 35 (6) ◽  
pp. 1722-1730
Author(s):  
Israa A. Alghamdi ◽  
Mohamed Abdelbaset ◽  
Ines El Mannoubi

The purpose of this paper was to synthesis new mixed-ligand Cu(II) and Co(II) metal complexes utilizing bidentate and tridentate donor hydrazones derivatives as primary ligands and o-vanillin as co-ligand. The obtained compounds were characterized by elemental analysis, Infrared, UV-Vis., 1H-NMR, Mass spectra, molar conductance, thermal analysis and atomic absorption spectroscopy (ASS). Spectroscopic analysis results indicated that the hydrazone ligand (L1) behave as tridentate (ONO) and forms metal complexes having distorted square planar geometry. While the ligands (L2, L3 AND L4) behave as bidentate (NO) and forms metal complexes having octahedral geometry around the central metal atoms. The antimicrobial potentials were assessed for the ligand (L2) and its metal complexes only and were screened against six types of bacterial strains and one fungal strain. The antimicrobial activities results of the tested compounds showed enhanced activity of the complexes over their parent ligands.


2021 ◽  
Vol 15 (1) ◽  
pp. 38-52
Author(s):  
Codjo Hountondji ◽  
Jacques H. Poupaert ◽  
Blanche Aguida ◽  
Fulbert K. Agbo Saga ◽  
Joël Pothier ◽  
...  

Background: The majority of scientists, physicians, and healthcare professionals were trained with the paradigm: “antibiotics are for bacteria only !”, because they misunderstood the definition of the ribosome targeting antibiotics. In the context of the current worldwide COVID-19 pandemic, it might be useful to recall as precisely as possible the definition of the word antibiotic and provide evidence that some classes of antibiotics could offer excellent means to counteract viral infections via specific mechanisms. Methods: Molecular modeling and docking studies were used, as well as the tRNAox labeling reaction of the ribosomal protein eL42 in situ on human 80S ribosomes to demonstrate that cycloheximide and its thiosemicarbazone analogues bind to the catalytic Lys-53 residue of the human large subunit ribosomal protein eL42. Results: Comparison of the binding sites for Cycloheximide (CHX) and Sparsomycin (SPS) on the evolutionarily conserved E. coli bL12 and S. cerevisiae eL42 by means of molecular modeling and docking studies showed that: (i) SPS binds in proximity to the catalytic Lys-65 residue of the GANK motif of rp bL12 and to the catalytic Lys-55 residue of the GGQTKP motif of rp eL42; (ii) CHX failed to bind to the GANK motif, while the glutarimide moiety of SPS and CHX was found to make contact with Lys-55 of the GGQTKP motif of rp eL42. Conclusion: In this report, we demonstrate that cycloheximide and its thiosemicarbazone analogues are capable of inhibiting the human 80S ribosomes selectively through their binding to the ε-amino group of the side chain of Lys-53. As a consequence, these small-molecule inhibitors of translation are susceptible to exhibit antiviral activities by preventing the human ribosomes of the SARS-CoV-2 infected cells from synthesizing the viral proteins and enzymes.


2020 ◽  
Vol 32 (4) ◽  
pp. 759-764
Author(s):  
K. Savitha ◽  
S. Vedanayaki

Co(II), Ni(II) and Cu(II) homo binuclear Schiff base metal complexes were synthesized from terephthalaldehyde and 2-amino-4-chlorophenol in methanol using template method. The structure of the ligand and its metal complexes were established by elemental, molar conductance, UV, magnetic moment, IR, 1H & 13C NMR, EPR, mass, thermal and PXRD. Molar conductance values showed that all complexes were non-electrolytic in nature. The IR spectral data provides the coordination of azomethine nitrogen and oxygen with central metal ion. UV, ESR and magnetic moment values suggest square planar geometry for Co(II), Ni(II) and Cu(II) complexes. TGA and DSC analysis data show the thermal stability of the ligand and its metal complexes. The crystalline nature of ligand and its metal complexes were investigated by powder-XRD. The DNA cleavage activities of all the complexes assayed on PUC18 DNA shows nuclease ability.


2018 ◽  
Vol 1154 ◽  
pp. 92-99 ◽  
Author(s):  
Raghavendra P. Bakale ◽  
Ganesh N. Naik ◽  
Shrinath S. Machakanur ◽  
Chandrashekhar V. Mangannavar ◽  
Iranna S. Muchchandi ◽  
...  

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