Anticancer, antioxidant, and antimicrobial studies and molecular docking of a new hexanuclear Zn(II) complex, together with its X-ray crystal analysis.

A new hexanuclear Zn(II) complex with the ligand 2,2'-(piperazine-1,4-diyl)bis(ethan-1-amine), [L3Zn6(OH)6][ClO4]6·3MeOH·7H2O, was synthesized. The crystal structure of this complex showed that each Zn atom is in a distorted tetrahedral coordination environment, surrounded by two nitrogen atoms from each ligand and two hydroxide groups, each of which bridges to another Zn atom. The anticancer activities of the ligand and its metal complex against the breast cancer cell line (MCF-7) indicated that the zinc complex had a greater anticancer activity. The free ligand and its metal complex were evaluated for antioxidant activity using the DPPH scavenging method. In addition, the antibacterial activities of both compounds were screened against Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria. The interaction of these compounds with DNA and AChE was also investigated using molecular docking.

Molecular docking and biological activities of Ni(II), Cu(II) and Co(II) complexes with a new potentially hexadentate polyamine ligand; X-ray crystal structure of the Cu(II) complex.

Three new metal complexes have been obtained from the reaction of a new polyamine (L) with Ni(II), Cu(II), and Co(II) ions. The X-ray structural analysis of the Cu(II) complex shows that the copper atom is in a very distorted square pyramidal environment, coordinated by five of the six nitrogen donor atoms of the potentially hexadentate ligand. To evaluate the biological potential of the ligand and the synthesized metal complexes, their binding behavior with DNA was studied by molecular modeling methods. The Molecular docking studies showed that the free ligand and its complexes were bound to the major groove of DNA. The antioxidant activities of the ligand and its metal complexes were also assessed, in vitro, using 2,2-diphenyl-1-picrylhydrazyl. The synthesized compounds were tested for activity against lung carcinoma epithelial cells (A549) using the MTT cell viability assay. A comparative study of the IC50 values indicated that the Cu(II) complex exhibited the highest activity, while the Co(II) and Ni(II) complexes showed more potent antiproliferative activity than the ligand. The antibacterial activities of the synthesized complexes were evaluated using micro-broth dilution and disk diffusion methods. The complexes showed greater antibacterial activity than the free ligand.Communicated by Ramaswamy H. Sarma.

The X-ray crystal structures, molecular docking and biological activities of two novel Cu(II) and Zn(II) complexes with a ligand having a potentially N4O2 donor set and two nitro phenyl rings as pendant arms.

A new ligand (L) containing two nitro phenyl rings as side chains was synthesized. The reaction of this ligand with copper(II) and zinc(II) metal ions gave complexes with different coordination environments. The free ligand and the metal complexes were characterized using a number of spectroscopic methods. The crystal structure of [ZnLBr]ClO4 showed that the Zn(II) ion was in a distorted square pyramidal environment. The crystal structure of [CuL](ClO4)2 showed that the Cu(II) ion is in a tetragonally distorted octahedral environment. Molecular docking studies with DNA indicated that the binding of L, [ZnLBr]ClO4 and [CuL](ClO4)2 involved the major groove of DNA, H-bonds and Vander Waals interactions. In contrast, the molecular docking of L, [ZnLBr]ClO4 and [CuL](ClO4)2 with human glutathione reductase (GR) showed that the dominant interactions of these compounds with GR were H-bonding, vander Waals and hydrophobic interactions. The antioxidant activity of the synthesized complexes was analyzed by the free radical scavenging activity using 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay with [CuL](ClO4)2 showing maximum activity. In addition, in vitro anticancer activity of the complexes against human breast MCF-7 cancer cell line was confirmed through 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium (MTT) assay. All compounds showed a dose-dependent inhibitory effect on the growth of breast cancer cells with the inhibition activity of [CuL](ClO4)2 being more active than the other synthesized compounds. Furthermore, results from the antibacterial activity screening of the compounds against two Gram-positive and Gram-negative pathogenic bacteria by the micro-broth dilution and disk diffusion methods indicated that [CuL](ClO4)2 complex had the strongest antibacterial potential.