Synthesis, characterization, antiproliferative of pyrimidine based ligand and its Ni(II) and Pd(II) complexes and effectiveness of electroporation.

In the study, a new Schiff base (ligand) was obtained using 4-aminopyrimidine-2(1H)-one, the starting material, and 2,3,4-trimethoxy benzaldehyde. Ni(II) and Pd(II) complexes were obtained from the reaction of the ligand and NiCl2·6H2O, PdCl2(CH3CN)2 (1:1 ratio). These compounds were characterized using the elemental and mass analysis, 1H, 13C-NMR, FT-IR, UV-Vis, magnetic susceptibility, thermal analysis, and the X-ray diffraction analyses. The antiproliferative activities of the synthesized ligand, Ni(II) and Pd(II) complexes were identified on the HepG2 (human liver cancer cells) cell line and their biocompatibility was tested on the L-929 (fibroblast cells) cell line by the MTT analysis method. Furthermore, the effects of electroporation (EP) on the cytotoxic activities of synthesized compounds were investigated in HepG2 cancer cells. According to the MTT findings of the study, the ligand did not exhibit an antiproliferative activity while its Ni(II) and Pd(II) complexes exhibited an antiproliferative activity. Moreover, it was observed that the antiproliferative activity of the Pd(II) complex was stronger than that of the Ni(II) complex. The combined application of EP + compounds is much more effective than the usage of the compounds alone in the treatment of HepG2 cancer cells. The EP increased the cytotoxicity of the Ni(II) and Pd(II) complexes by 1.66, and 2.54 times, respectively. It was concluded that Ni(II) and Pd(II) complexes may contribute as potential anti-cancer agents for the treatment of hepatocellular carcinoma and yield promising results in the case of being used in ECT.Communicated by Ramaswamy H. Sarma.

Some metal chelates with Schiff base ligand: synthesis, structure elucidation, thermal behavior, XRD evaluation, antioxidant activity, enzyme inhibition, and molecular docking studies.

Schiff bases are well-known compounds for having significant biological properties. In this study, a new Schiff base ligand and its metal complexes were synthesized, and their antioxidant and enzyme inhibitory activities were evaluated. The new Schiff base ligand was synthesized with the condensation reaction of 6-tert-butyl 3-ethyl 2-amino-4,5-dihydrothieno[2,3-c]pyridine-3,6(7H)-dicarboxylate and 2-hydroxybenzaldehyde compounds. Fe(II), Co(II), and Ni(II) metal complexes of the novel Schiff base ligand were synthesized and characterized. The purity and molecular formula of the synthesized compounds were identified with elemental analysis, infrared, ultraviolet-visible, mass spectrophotometry, powder XRD, magnetic and thermal measurements. The Schiff base acted as a three dentate chelate. The analytical and spectroscopic data suggested an octahedral geometry for the complexes. The in vitro antioxidant method studies elucidated a more effective antioxidant character of the Schiff base ligand than its metal complexes but a less effective antioxidant potential than the standard antioxidant compounds. The enzyme inhibition potentials of the synthesized compounds for AChE, BChE, and GST enzymes were determined by in vitro enzyme activity methods. The Schiff base ligand was discovered to be the best inhibitor for the AChE and BChE with the values of 7.13 ± 0.84 µM and 5.75 ± 1.03 µM Ki, respectively. Moreover, the Fe(II) complex displayed the best Ki value as 9.37 ± 1.06 µM for the GST enzyme. Finally, molecular docking studies were carried out to see the structural interactions of the compounds. The metal complexes demonstrated better binding affinities with the AChE, BChE, and GST enzymes than the Schiff base ligand. This study identified a potential Schiff base molecule against both AChE and BChE targets to further investigate for in vivo and safety evaluation.

Synthesis, characterization, powder X-ray diffraction analysis, thermal stability, antioxidant properties and enzyme inhibitions of M(II)-Schiff base ligand complexes.

The Schiff base ligand ((E)-6-methyl-2-(2,3,4-trimethoxybenzylideneamino)-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carbonitrile) and its cobalt(II) and palladium(II) complexes were successfully prepared. The structure of the compounds was elucidated by various techniques (NMR, FT-IR, powder X-ray diffraction, microanalysis, TGA, magnetic susceptibility, mass spectrometry). The Pd(II) complex showed a square planar geometry and the Co(II) complex had an octahedral geometry. ABTS (2,2-azino-bis 3-ethylbenzothiazloine-6-sulphonic acid), DPPH (1,1-diphenyl-2-picrylhydrazyl), FRAP (ferric-reducing antioxidant power) and CUPRAC (cupric reducing antioxidant capacity) in vitro methods were applied to identify the antioxidant features of the synthesized compounds. In addition, glutathione S-transferase and acetyl/butyryl cholinesterase enzymes were examined for possible inhibition capacities of the complexes. According to the enzyme activity measurements, Ru(II) complex inhibited both GST and BChE enzymes, while Fe(II) complex inhibited only AChE enzyme. Furthermore, the antioxidant activities and enzyme inhibitions of the previously synthesized Fe(II) and Ru(II) complexes of the same ligand were examined to make a comparison of the metal complexes.Communicated by Ramaswamy H. Sarma.

Spectroscopic and Structural Characterization, Enzyme Inhibitions, and Antioxidant Effects of New Ru(II) and Ni(II) Complexes of Schiff Base.

The new complex compounds [RuLCl(p-cymene)] ⋅ 3H2 O and [NiL2 (H2 O)2 ] ⋅ 3H2 O (L: 1-{4-[(2-hydroxy-3-methoxybenzylidene)amino]phenyl}ethanone) were prepared and characterized using FT-IR, 1 H- and 13 C-NMR, mass spectroscopy, TGA, elemental analysis, X-ray powder diffraction and magnetic moment techniques. Octahedral geometry for new Ni(II) and Ru(II) complexes was proposed. Thermal decomposition confirmed the existence of lattice and coordinated water molecule in the complexes. To determine the antioxidant properties of Schiff base ligand and its Ni(II), Ru(II) metal complexes, FRAP, CUPRAC, ABTS and DPPH methods of antioxidant assays were used. Moreover, enzyme inhibition of complexes was evaluated against carbonic anhydrase I and II isoenzymes (CA I and CA II) and acetylcholinesterase (AChE). For CA I and CA II, the best inhibition enzymes, was the Ni(II) complex with 62.98±18.41, 86.17±23.62 Ki values, whereas this inhibition effect showed ligand with 24.53±2.66 Ki value for the AChE enzyme.