DNA-targeting potential and biomedical applications of selected phenolic Schiff base metal complexes: a molecular...

Metal-based compounds continue to attract considerable attention as bioactive agents due to their versatile coordination behavior and ability to modulate biomolecular structure and function. In this study, a phenolic Schiff base ligand, 2-[(5-methoxy-2-hydroxy-phenylimino)methyl]-4-nitrophenol (MHNP), was utilized to synthesize a series of Ru(III), Zn(II), and VO(II) complexes. The structures of the obtained complexes were elucidated using various spectroscopic techniques, and their stability was evaluated to assess suitability for biological applications. Density functional theory (DFT) calculations were performed to provide molecular-level insight into electronic properties and preferred coordination geometries. The combined experimental and theoretical results indicate that the MHNP ligand coordinates through NOO donor atoms, forming octahedral geometry with Ru(III), tetrahedral geometry with Zn(II), and square pyramidal geometry with VO(II) complexes. DNA interaction studies were conducted to evaluate the binding affinity of the complexes toward double-stranded DNA. The results demonstrate enhanced DNA-binding upon metal coordination, with binding modes dependent on the metal center. Notably, the Ru(III) complex exhibited stronger interactions, suggesting groove-binding or intercalative behavior, while Zn(II) and VO(II) complexes showed moderate but stable binding profiles. Structure-interaction relationships highlight the significant role of metal ions in tuning biomolecular recognition. Additionally, the redox properties of Ru(III) and VO(II), along with the redox-modulating nature of Zn(II), suggest potential antioxidant activity through regulation of reactive oxygen species. Overall, these findings indicate that MHNP-based metal complexes are promising multifunctional candidates for antimicrobial, anticancer, and antioxidant applications, offering a rational basis for the development of metal-based therapeutics.