Voltammetric studies of the interaction of nogalamycin antitumor drug with DNA

The interaction of nogalamycin (NOM), an anthracycline antitumor drug, with calf thymus DNA has been studied by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The variations in the cyclic voltammetric behaviour of NOM on addition of DNA have been carried out. The experimental results reveal that the reduced form (H2NOM)(red), of NOM is bound more strongly to DNA than the oxidised form (NOM)(ox), The calibration graph for the determination of DNA was obtained by the decrease in the DPV peak current of NOM in the presence of DNA. Furthermore, the results are compared with the similar type of interaction behaviours of daunomycin (DAM), adriamycin (ADM) and 4 ' -deoxyadriamycin (DADM), mainly from the viewpoint of the influence of chemical structure. Binding constants were determined from voltammetric data, i.e. changes in limiting current with addition of DNA. In comparison with DAM, ADM and DADM, nogalamycin displayed high binding affinity to DNA (K = 4.44 x 10(5) M-1), and the binding affinity increases in the sequence: DAM < DADM < ADM < NOM. The results show also that, a slight change in chemical structure causes significant changes in the binding affinity to DNA and consequently in clinical properties. (C) 2001 Elsevier Science B.V. All rights reserved.