Ruthenium(II)/(III) complexes of 4-hydroxy-pyridine-2,6-dicarboxylic acid with PPh3/AsPh3 as co-ligand: Impact of oxidation state and co-ligands on anticancer activity in vitroElectronic supplementary information (ESI) available: 1H NMR spectrum of the complex [RuII-hpa-P] (Fig. S1). Cyclic voltammetric response of [RuII-hpa-P] (Fig. S2). X-Ray crystal structure and atom numbering scheme for [RuIII-hpa-As] (Fig. S3). Hydrogen-bonding distances and angles (Table S1). Plot of (af)/(bf) vs. [DNA] f

• Main Authors: Kamatchi, Thangavel Sathiya, Chitrapriya, Nataraj, Lee, Hyosun, Fronczek, Chris F, Fronczek, Frank R, Natarajan, Karuppannan
• Format: Article
• Language: English
• ISSN: 1477-9226; 1477-9234
• DOI: 10.1039/c1dt11273b

With the aim to develop more efficient, less toxic, target specific metal drugs and evaluate their anticancer properties in terms of oxidation state and co-ligand sphere, a sequence of Ru II , Ru III complexes bearing 4-hydroxy-pyridine-2,6-dicarboxylic acid and PPh 3 /AsPh 3 were synthesized and structurally characterized. Biological studies such as DNA binding, antioxidant assays and cytotoxic activity were carried out and their anticancer activities were evaluated. Interactions of the complexes with calf thymus DNA revealed that the triphenylphosphine complexes could bind more strongly than the triphenylarsine complexes. The free radical scavenging ability, assessed by a series of in vitro antioxidant assays involving DPPH radical, hydroxyl radical, nitric oxide radical, superoxide anion radical, hydrogen peroxide and metal chelating assay, showed that the Ru III complexes possess excellent radical scavenging properties compared to those of Ru II . Cytotoxicity studies using three cancer lines viz HeLa, HepG2, HEp-2 and a normal cell line NIH 3T3 showed that Ru II complexes exhibited substantial cytotoxic specificity towards cancer cells. Furthermore, the Ru II complexes were found to be superior to Ru III complexes in inhibiting the growth of cancer cells. We investigate the effects of oxidation states of ruthenium and the size of the ligands present in the complexes on DNA binding, antioxidant activity and cytotoxicity.