Synthesis and crystal structure determination of cobalt(II) mixed-ligand complex containing 1,10-phenanthroline and 5-(2-carboxybenzyloxy)isophthalic acid: Their biological evaluation viz. DNA/protein binding profile, pBR322 DNA cleavage activity

•New Co(II)-based complex was synthesized and characterized.•In vitro DNA binding studies revealed the electrostatic mode of binding.•Complex 1 shows efficient pBR322 DNA cleavage induced by ROS.•Complex 1 recognizes minor groove.

New metal-based cancer chemotherapeutic agent Co(II) complex of the type{[Co(Me2Phen)(o-cbiaH)(H2O)2]·H2O} (1) was synthesized from ligand 5-(2-carboxybenzyloxy)isophthalic acid (o-cbiaH3) and thoroughly characterized by spectroscopic and single crystal X-ray diffraction method. Complex 1 crystallizes in a slightly distorted octahedral CoN2O4 coordination environment. In vitro DNA binding studies of ligand and complex 1 with CT DNA were carried out by using biophysical techniques viz electronic absorption and fluorescence spectral studies which indicated that 1 binds to DNA more avidly as compared to ligand via electrostatic binding mode. Complex 1 shows significant DNA photo cleavage activity through the formation of hydroxyl radicals via photo-redox pathway. The affinity of 1 towards HSA was also investigated by the fluorescence spectroscopic technique and 3D scan measurements revealing that 1 quench the fluorescence intensity of HSA more strongly than o-cbiaH3. Furthermore, magnetic drug targeting shows the accumulation of complex 1 in the target site under the influence of an externally applied magnetic force.

Graphical abstractNew mononuclear cobalt(II) Schiff base complex was designed and synthesized, targeting DNA using carrier protein HSA.Figure optionsDownload full-size imageDownload as PowerPoint slide