Ruthenium(II) complexes of curcumin and β-diketone derivatives: effect of structural modifications on their cytotoxicity

Ruthenium(II) complexes ( Ru1 – Ru3 ) with the general formula Ru(O-O)(PPh 3 ) 2 (bipy)PF 6, bearing two triphenylphosphine (PPh 3 ), bipyridine (bipy) and a series of natural and synthetic β-diketones (O,O) ligands were synthesized and characterized using various analytical techniques. The interaction between the complexes and calf thymus DNA (CT-DNA) was investigated and demonstrated a weak interaction. The cytotoxicity of the complexes was investigated against breast cancer cells (MDA-MB-231 and MCF-7), lung cancer cells (A549), cisplatin-resistant ovarian cancer cells (A2780 cis ), as well as non-tumour lung (MRC-5) and non-tumour breast (MCF-10A) cell lines. All complexes exhibited cytotoxic activity against all the cell lines studied, with half maximal inhibitory concentration (IC 50 ) values ranging from 0.39 to 13 µM. Notably, the three complexes demonstrated selectivity against the A2780 cis cell line, with IC 50 ranging from 0.39 to 0.82 µM. Among them, Ru2 exhibited the highest cytotoxicity, with an IC 50 value of 0.39 µM. Consequently, this new class of complexes shows good selectivity towards cisplatin-resistant ovarian cancer cells and it is promising for further investigation as anti-cancer agents.