Spectroscopic and computational studies on DNA/BSA binding and cytotoxicity of a new Pd(II)-phen-salicylate complex

A new Pd(II)-phen-salicylate complex i.e. [Pd(phen)(SA)] was synthesized and characterized to evaluate its biological potential. This salicylate based complex is structurally and electronically distinct from previously reported Pd(II)-bpy or Pd(II)-phendione analogues, introducing salicylate in conjugation with 1,10-phenanthroline (phen) for the first time. Spectroscopic studies, supported by computational modeling, revealed that the complex interacts with DNA mainly through stable hydrogen bonds, while also forming hydrogen bonding and van der Waals forces with bovine serum albumin (BSA). MD simulations confirmed the stability of the Pd(II) complex-DNA/BSA adducts over time and provided insight into their dynamic conformational behavior. Binding constants (K_b,DNA = 5.30 × 10⁴ and K_b,BSA = 2.22 × 10⁵) and molecular docking provided insight into the spontaneity and orientation of these interactions. Cytotoxicity assays against human cancer cell lines (K562) demonstrated that the Pd(II) complex exhibits measurable antiproliferative activity (IC₅₀ = 37 µM), with results compared to cisplatin as the reference drug. Overall, these findings highlight the potential of new [Pd(phen)(SA)] complex and suggest its potential as a promising scaffold for the development of new Pd-based therapeutic agents.