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

Two new complexes ZnL(2)x2H(2)O (1) and CuL(2)x2H(2)O (2) (HL=1-hydroxy-6-(2-(1-piperidinyl)ethoxy)xanthone) have been synthesized and characterized. Their interactions with calf thymus DNA (ct DNA) were investigated by absorption spectroscopy, fluorescence spectroscopy, ethidium bromide (EB) displacement experiments, circular dichroism spectroscopy and viscosity measurements. Experimental results suggested that there were intercalative interactions of the complexes with DNA. The binding affinity of complex 2 was higher than that of 1. In addition, the cytotoxic effects of both complexes were evaluated with lung adenocarcinoma (GLC-82), esophagus squamous cancer (ECA109) and human gastric cancer (SGC7901) cells using MTT assay. Both were potent exhibiting significant cytotoxicity in vitro.