Synthesis, DNA-binding, and antitumor activity of polypyridyl-ruthenium(II) complexes [Ru(L)₂(DClPIP)] (L = bpy, phen; DClPIP = 2-(2,4-dichlorophenyl)-1H-imidazo[4,5-f][1, 10]phenanthroline)

Abstract

Two new ruthenium(II) complexes, [Ru(bpy)₂(DClPIP)](ClO₄)₂ (1) and [Ru(phen)₂(DClPIP)](ClO₄)₂ (2) (bpy = 2,2′-bipyridine, phen = 1,10-phenanthroline, and DClPIP = 2-(2,4-dichlorophenyl)-1H-imidazo[4,5-f][1, 10]phenanthroline), have been prepared in high yield by using microwave-assisted synthesis technology. The anticancer activity of the two ruthenium(II) complexes against A549, C6, CNE-1 and MDA-MB-231 cell lines has been evaluated by MTT assay and results showed that 2 exhibited higher antitumor activity than 1 toward all the selected tumor cell lines. Besides, A549 cell line was sensitive to both ruthenium(II) complexes, especially to 2 (IC₅₀ = 8.01 ± 0.36 μM). Meanwhile, 2 showed low toxicity against MCF-10A human normal cells. Furthermore, the DNA-binding properties of the two new ruthenium(II) complexes with CT-DNA have been investigated by electronic absorption titration, luminescence spectra, circular dichroism spectra and viscosity measurements. The results suggested that 1 and 2 were able to interact with CT-DNA via intercalative mode with a strong binding affinity in the order 2 > 1. All of these results suggested that anticancer activity of both ruthenium(II) complexes could be closely related to their interaction with DNA.

Graphical Abstract

Keywords:

• Ruthenium(II) polypyridyl complexes
• microwave-assisted synthesis
• antitumor activity
• DNA-binding

Disclosure statement

Shouhai Guan and Tao Pan contributed equally to the work. No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the National Nature Science Foundation of China [grant number 81572926, 81703349]; the Provincial Major Scientific Research Projects in Universities of Guangdong Province [grant number 2014KZDXM053]; the Science and Technology Project of Guangdong Province [grant number 2014A020212312, 2017zc0213]; the Innovation Projects in Universities of Guangdong Province [grant number 2015cxqx151]; the Tradition Chinese Medicine Bureau of Guangdong Province [grant number 20151265]; the Innovation Team Projects in Universities of Guangdong Province [grant number 2016KCXTD018]; the Major Project of the Education Department of Guangdong Province [grant number 2017KZDXM051]; and the Technology Plan of Guangdong Province-Social Development Project [grant number 2017A020215021].