Synthesis of Ca(II), Mg(II), and VO(II) tridentate Schiff Base complexes as potential antitumor candidates: Spectroscopic, antioxidant activity, DFT, and DNA docking studies

Abstract

In this work, an imine ligand was created by condensing 2-amino-3-hydroxypyridine with o-vanillin. Schiff base complexes of Ca(II), Mg(II), and VO(II) were developed and characterized through IR, TGA, UV/Vis, and ¹H NMR procedures in conjunction with elemental (CHN) analysis, mass spectrometry, conductivity, magnetic characteristics, and powder X-ray diffraction (XRD). The octahedral forms of the Ca(II) and Mg(II) are verified by spectrophotometric and magnetic susceptibility examinations. All complexes exhibit outstanding antimicrobial properties against a range of bacterial and fungal species, as demonstrated by biological research. The overall sequence of antimicrobial effectiveness was VO(II) > Mg(II) > Ca(II) > H₂D, with the VO(II) complex displaying the greatest antibacterial potency and the widest inhibition zone towards Gram-negative bacteria. In contrast, antifungal assays towards Aspergillus flavus revealed an activity trend of Ca(II) > Mg(II) > VO(II) > H₂D, with the Ca(II) complex displaying the greatest antifungal potency. Moreover, the synthesized complexes exhibited significant cytotoxic potency towards cancer cell lines, particularly HCT-116, with the Ca(II) complex displaying the highest anticancer activity (IC₅₀ = 5.36)when compared to Vinblastine. In addition, these compounds demonstrated remarkable free radical scavenging potential, highlighting their promising antioxidant properties. Theoretically, the equilibrium geometries of the ligand and its metal complexes were optimized via Density Functional Theory (DFT) simulations. Finally, to clarify the potential binding mechanisms of the developed complexes to the active sites of bacterial and human DNA receptors, molecular docking experiments were conducted.