Iridium(III) Complexes for Lung Cancer Therapy: Recent Advances and Case Studies in DNA Targeting, Antioxidant Activity and Cytotoxicity

ABSTRACT Lung cancer remains a leading cause of cancer‐related mortality, and resistance to platinum‐based chemotherapy necessitates the development of alternative metal‐based therapeutics. In this study, two iridium(III) complexes were synthesized and systematically investigated for their photophysical and biological properties. Spectroscopic characterisation confirmed effective ligand coordination and metal‐to‐ligand charge transfer behaviour. Both complexes exhibited significant interaction with calf thymus DNA, with intrinsic binding constants of 5.01 × 10 4 M −1 and 1.08 × 10 4 M −1 , and showed strong affinity towards human serum albumin (K HSA up to 8.30 × 10 6 M −1 ). Antioxidant activity assessed by the DPPH assay revealed moderate radical scavenging ability. Cytotoxicity studies using an MTT assay demonstrated concentration‐dependent antiproliferative activity against A549 lung cancer cells, with IC 50 values of 57.6 µM and 36.0 µM, while maintaining low toxicity towards normal HEK 293 cells.