Synthesis and multi-target biological evaluation of Schiff base metal complexes: tuning anticancer efficacy and enzyme inhibition via metal center variation.

A novel series of Schiff base metal complexes Cu(II), Ni(II), Co(II), and Zn(II) were produced from 4-dimethyl amino benzaldehyde and L-leucine. These generated compounds were investigated for their biological activities comprising of anticancer, DNA binding, antioxidant, anti-diabetic, and anti-inflammatory assay. The outcomes demonstrate that the coordinated metal ion enact a substantial aspect in modulating bioactivity. Among the complexes, Cu(II) revealed the highest cytotoxicity against HeLa cells, exhibited a concentration-dependent decrease in viability, while free ligand remained largely inactive. DNA binding studies revealed moderate to strong interactions with CT-DNA, predominantly through intercalation, following the series: Cu(II) > Ni(II) > Co(II) > Zn(II), correlating by their cytotoxic effects. In antioxidant and anti-inflammatory assays, Cu(II) showed the highest activity, whereas Zn(II) displayed superior α-glucosidase inhibition, indicating promising anti-diabetic potential. Molecular docking further supported these findings, highlighting strong binding interactions of Cu(II) with biomolecular targets and favorable enzyme binding for Zn(II). The study establishes a clear structure-activity relationship governed by the metal center. The Cu(II) complex emerges as a promising multifunctional candidate with notable anticancer and biomolecular interactions, while the Zn(II) complex shows potential for anti-diabetic applications. These findings provide useful insights for the design of metal-based therapeutic agents.