Antioxidant and Anticancer Potential of the New Cu(II) Complexes Bearing Imine-Phenolate Ligands with Pendant Amine N-Donor Groups

Abstract

Cu(II) complexes bearing NNO-donor Schiff base ligands (2a, b) have been synthesized and characterized. The single crystal X-ray analysis of the 2a complex revealed that a mononuclear and a dinuclear complex co-crystallize in the solid state. The electronic structures of the complexes are optimized by Density Functional Theory (DFT) calculations. The monomeric nature of 2a and 2b species is maintained in solution. Antioxidant activities of the ligands (1a, b) and Cu(II) complexes (2a, b) were determined by in vitro assays such as 1,1-diphenyl-2-picrylhydrazyl free radicals (DPPH.) and 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) radicals (ABTS+). Our results demonstrated that 2a showed better antioxidant activity. MTT assays were performed to assess the toxicity of ligands and Cu(II) complexes in V79 cells. The antiproliferative activity of compounds was tested against two human tumor cell lines: MCF-7 (breast adenocarcinoma) and SW620 (colorectal carcinoma) and on MRC-5 (normal lung fibroblast). All compounds showed high cytotoxicity in the all-cell lines but showed no selectivity for tumor cell lines. Antiproliferative activity by clonogenic assay 2b showed a more significant inhibitory effect on the MCF-7 cell lines than on MRC-5. DNA damage for the 2b compound at 10 µM concentration was about three times higher in MCF-7 cells than in MRC-5 cells.

Copper(II) Complexes with 1-(Isoquinolin-3-yl)heteroalkyl-2-ones: Synthesis, Structure and Evaluation of Anticancer, Antimicrobial and Antioxidant Potential

“…It could be concluded that in the DPPH assay, the coordination of ligands to the copper(II) metal center appears to be beneficial for antiradical potency as was previously reported [ 88 , 89 , 90 ]. In general, no similar correlation was found for complexes C1 – 4 compared with their ligands L1 – 4 in the ABTS analysis.…”

“…The free radical scavenging abilities of the free ligands, L1 , L2 , L3 and L4 , and the corresponding copper(II) complexes, C1 , C2 , C3 and C4 , were analyzed with two colorimetric methods, DPPH (2,2′-diphenyl-1-picrylhydrazyl) and ABTS (2,2′-azinobis(3-ethylbenzothiazoline-6-sulphonic acid) assays, which were previously used to study the antioxidant activities of the Cu(II) complexes [ 88 ]. The results are expressed as IC 50 —the sufficient concentration to obtain 50% of the maximum scavenging activity—and they are shown in Table 5 .…”

“…The DPPH radical scavenging assay of samples was performed with ascorbic acid as a positive control [ 88 ]. Briefly, 100 μL of different concentrations of the complexes, dissolved in DMSO, was mixed with 100 μL of 0.06 mM DPPH methanolic solution and incubated at room temperature in the dark for 30 min.…”

“…The ABTS radical scavenging assay of samples (ligands or complexes) was performed with ascorbic acid as a positive control [ 88 ]. Briefly, 30 μL of different concentrations of the samples, dissolved in DMSO, was mixed with 170 μL of ABTS solution (2 mM ABTS diammonium salt, 3.5 mM potassium persulfate) and completed with water to a final volume of 300 μL.…”

Cytotoxic Cu(II) Complexes with a Novel Quinoline Derivative Ligand: Synthesis, Molecular Docking, and Biological Activity Analysis

“…Imine-based ligands, like quinolines and N-donor metal complexes, have generated significant interest due to their fascinating chemical properties and potential biological uses, including antibacterial, and anticancer effects. , Quinolines are versatile heterocyclic aromatic compounds containing nitrogen and various moieties . They are present in both synthetic and naturally occurring biologically active substances, making them crucial in pharmaceutical research for development of novel drugs .…”