Synthesis and characterization of the Zn(II) and Cu(II) piperidinyl isoeuxanthone complexes: DNA-binding and cytotoxic activity

Two new complexes, Zn(II) complex (1) and Cu(II) complex (2) with piperidinyl isoeuxanthone (1-hydroxy-6-(2-(1-piperidinyl)ethoxy)xanthone) have been synthesized and characterized. The interactions of them with calf thymus DNA (ct DNA) were investigated by absorption spectroscopy, fluorescence spectroscopy, ethidium bromide (EB) displacement experiments, circular dichroism (CD) spectroscopy and viscosity measurements. Experimental results indicated intercalative interaction with DNA for the complexes and the binding affinity of complex 2 is higher than that of 1. Moreover, the two complexes had potent cytotoxic activities toward three human cell lines, lung adenocarcinoma (GLC-82), esophagus squamous cancer (ECA109) and human gastric cancer (SGC7901) cells. The result of inhibitory effect in vitro is consistent with the result of DNA-binding studies.