Microwave-Assisted Synthesis, Characterisation, and DNA-Binding Properties of RuII Complexes Coordinated by Norfloxacin as Potential Tumour Inhibitors

Three novel norfloxacin-based ruthenium(ii) complexes, [Ru(bpy)(2)(NFLX)]Cl2H(2)O (1), [Ru(phen)(2)(NFLX)]Cl2H(2)O (2), and [Ru(dmbpy)(2)(NFLX)]Cl2H(2)O (3) (bpy=2,2-bipyridine, phen=1,10-phenanthroline, dmbpy=4,4-dimethyl-2,2-bipyridine, and NFLX=norfloxacin), were synthesised and characterised with electrospray ionisation mass spectrometry and H-1 and C-13 NMR spectroscopy. The antitumour properties were evaluated by MTT assay, and the data revealed that 2 can inhibit the growth of human lung adenocarcinoma A549 efficiently. Furthermore, the DNA-binding behaviours of these complexes were investigated by a multiple spectroscopy assay and viscosity study. The results indicated that these complexes interact with calf thymus DNA through electrostatic interactions with a strong binding affinity in the order 2>3>1. Therefore, these results suggested that 2 might be a suitable anticancer agent due to its excellent DNA-binding abilities.