Cytotoxic Activity and Molecular Docking Studies of ONNO Type Salophen Schiff Base Metal Complexes

A Schiff base ligand (H₂L) was synthesized through the condensation of 3,5-dibromo-2-hydroxybenzaldehyde with 1,2-phenylenediamine and subsequently complexed with Cu(II), Ni(II), Pt(II), Fe(II), and Pd(II) ions. Synthesized compounds were examined using FT-IR, UV-Vis, NMR, mass, elemental analysis, molar conductivity, and magnetic susceptibility. The H₂L and transition metal complexes were tested for their cytotoxic activity potential against human liver carcinoma (HepG2) and lung adenocarcinoma (A549) cell lines. The cytotoxic activities of compounds were determined based on their IC₅₀ values. The Pt(II) complex exhibited high cytotoxic activity against both HepG2 and A549 cell lines; the IC₅₀ values were obtained as 13.32 and 12.26 µM, respectively. In contrast, the Ni(II) and Fe(II) complexes displayed relatively weaker cytotoxic effects. The geometry of the PtL complex was optimized through density functional theory (DFT) calculations. Molecular docking studies were conducted to elucidate the noncovalent interactions between the optimized PtL complex and the active sites of protein BCL-2 (PDB ID: 6QGK), selected as a putative molecular target relevant to HepG2 cells, using the DFT optimized geometry of PtL.