Synthesis, spectroscopic and biological activity evaluation of Ni(II), Cu(II) and Zn(II) complexes of schiff base derived from pyridoxal and 4-fluorobenzohydrazide

Abstract

A novel Schiff base ligand, 4-fluoro-N-((3-hydroxy-5-(hydroxymethyl)-2-methylpyridin-4-yl)methylene)benzohydrazide (PLFBH) was synthesized by condensationof pyridoxal and 4-fluorobenzohydrazide. Its complexes with Ni(II), Cu(II), and Zn(II) metal ionswere prepared and characterized by spectroscopic IR, ¹H-NMR, UV, LC-MS, ESR, and powder XRD studies and by elemental analysis and thermal analysis, molar conductance, and magnetic susceptibility measurements. The results indicate the geometry of the complexes to be hexa coordinate distorted octahedral. Based on the electronic absorption and fluorescence emission spectra and viscosity studies, an intercalative mode of binding of the complexes with CT-DNA was suggested, which was also supported by DNA docking studies. The docking studies of metal complexes with DNA were carried out using Autodock 4.2. The in vitro anticancer assay for the Cu(II)-PLFBH complex was performed to assess the ability of the complex to inhibit human cell proliferation on HeLa human cervical carcinoma cells, MCF-7 human breast carcinoma cells, and A549 human lung carcinoma cells. The Cu(II)-PLFBH complex exhibited moderate to good inhibitory effect on the cancer cell lines studied. The complexes showed good cleavageability toward plasmid pBR322 DNA. The metal complexes were found to show good antibacterial activity against gram positive bacteria, Staphylococcus aureus and Bacillus cereus and gram negative bacteria Escherichia coli and Pseudomonas aeruginosa cultures,while the ligand showed marginal activity.

Supplemental data for this article is available online at https://doi.org/10.1080/15257770.2021.1961271 .

GRAPHICAL ABSTRACT

The Ni(II), Cu(II), and Zn(II) complexes of schiff base ligand, 4-fluoro-N-((3-hydroxy-5-(hydroxymethyl)-2-methylpyridin-4-yl)methylene)benzohydrazide (PLFBH) derived from pyridoxal and 4-fluorobenzohydrazide were synthesized and characterized by various spectro-analytical techinques. The results indicate the geometry of the complexes to be hexa coordinate tetragonally distorted octahedral. Their DNA binding, cleavage, in vitro anticancer activity, molecular docking and antibacterial activity studies were carried out. All the metal complexes were found to show moderate to good biological activity.

Keywords:

• Metal complexes
• pyridoxal
• Schiff base
• DNA binding
• DNA cleavage
• anticancer assay
• DNA docking and antibacterial

Acknowledgment

The authors are thankful to Jawaharlal Nehru Technological University Hyderabad, Hyderabad and Osmania University, Hyderabad, India for providing research facilities to carry out this work.

Disclosure statement

The authors declare that there are no conflicts of interest.