Evaluation of DNA-binding, radical scavenging and cytotoxic activity of five coordinated Cd(ii) complexes containing 2-acetylpyridine-N4-substituted thiosemicarbazone

Abstract

A series of new five coordinated Cd(II) complexes of the type [Cd(Lⁿ)Cl₂] (n = 1–3) have been isolated and characterized using analytical, spectral and structural methods. The single crystal X-ray structure of one of the complexes [Cd(L²)Cl₂] (2) has been determined and a distorted square pyramidal geometry has been found, in which Cd(II) is coordinated with two nitrogens, one sulfur and two chlorine atoms. The interactions of the complexes with calf thymus DNA (CT-DNA) have been explored by absorption, competitive, thermal denaturation and viscometric methods, which revealed that the compounds could interact with CT-DNA through groove binding. Investigation of the antioxidant properties showed that the Cd(II) complexes have a strong radical scavenging tendency against DPPH˙, OH˙ and NO˙ radicals. Further, the cytotoxic effect of the compounds examined on a human breast cancer cell line (MCF-7) showed that the complexes exhibited substantial cytotoxic activity.