Redox mechanism of anticancer drug idarubicin and in-situ evaluation of interaction with DNA using an electrochemical biosensor.

Idarubicin (IDA), 4-demethoxydaunorubicin, is an anthracycline derivative and widely used treatment of leukemia. The electrochemical behavior of IDA was examined at a glassy carbon electrode (GCE) in different aqueous supporting electrolyte using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The oxidation process of IDA was found to be pH dependent and irreversible proceeding with a transfer of 1 proton and 1 electron under the diffusion controlled mechanism. The electroactive center is the hydroxyl group on the aromatic ring which produces a final quinonic product. The diffusion coefficient of IDA was calculated to be DIDA=7.47×10(-6) cm(2) s(-1) in pH=4.3 0.1 M acetate buffer. The interaction of IDA and double stranded deoxyribonucleic acid (ds-DNA) was investigated using electrochemical ds-DNA biosensor and incubation solution by means of DPV. The DNA damage was detected following the changes in the oxidation peaks of guanosine and adenosine residues. The results obtained showed that IDA interacts with DNA which causes the change in the DNA morphological structure. In addition to these polynucleotides, PolyG and PolyA, biosensors were also used to confirm the interaction between ds-DNA and IDA. However, no oxidation peaks of the purine base oxidation products, 8-oxoGua and 2,8-oxoAde, were observed.