Novel Ruthenium(II)-8-Hydroxyquinoline Derivative Complexes as Anticancer Candidates

Six novel ruthenium(II) complexes containing halogenated and sulfonated 8-hydroxyquinoline derivatives were synthesized, characterized, and biologically evaluated as potential metallodrugs. Spectroscopic, analytical, electrochemical, and single-crystal X-ray diffraction studies confirmed their structures and properties. The complexes were stable under biological conditions and exhibited lipophilic character (LogP > 0). DNA-binding studies suggested interactions through the minor groove, while BSA assays indicated electrostatic binding via a static quenching mechanism (Kb ≈ 10⁴–10⁵ M⁻¹). Complexes showed remarkable cytotoxicity against MDA-MB-231, MCF-7, A2780, and A549 cancer cell lines (IC₅₀ = 0.14–1.68 μM), displaying selectivity toward A2780 ovarian cancer cells relative to MRC-5 non-cancerous cells. Mechanistic-action studies suggested a possible ROS-mediated cell death, highlighting its potential as a promising candidate for further anticancer drug development.