DNA-binding, antioxidant activity, and bioactivity studies of ruthenium(II) complexes containing amino substituents

Abstract

Two new Ru(II) complexes, [Ru(dmp)₂(dadppz)](ClO₄)₂ (1) and [Ru(dip)₂(dadppz)](ClO₄)₂ (2), were synthesized and characterized by elemental analysis, ES-MS, and ¹H NMR. DNA-binding behaviors were investigated by absorption titration and luminescence spectra. The DNA-binding constants were 3.1 (± 0.2) × 10⁴ and 3.0 (± 0.2) × 10⁵ M⁻¹ for 1 and 2. The antioxidant activity of these complexes against hydroxyl radical () was explored. The cytotoxicities in vitro towards A549, BEL-7402, MG-63, and SKBR-3 cells were studied by 3-(4,5dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method. Complex 1 shows high cytotoxicity, but 2 is not cytotoxic towards the selected cell lines. Apoptosis and cell cycle distribution were studied by flow cytometry. The cellular uptake showed that complexes can enter into the cytoplasm. JC-1 was used as a fluorescence probe in detecting the mitochondrial membrane potential and results indicate that the mitochondrial membrane potential decreases.

Keywords:

• Ruthenium(II) complexes
• DNA-binding
• Antioxidant activity
• Bioactivity

Acknowledgments

This work was financially supported by the National Nature Science Foundation of China (No. 31070858) and Guangdong Pharmaceutical University.