Spectroscopic studies on the interaction of gamma-cyclodextrin daunorubicin inclusion complex with herring sperm DNA

The interaction of daunorubicin (DNR) with herring sperm DNA in cyclomaltooctaose (gamma-cyclodextrin, abbrev. gamma-CD) supramolecular system was studied by UV-vis absorption spectroscopy, fluorescence spectroscopy and viscosity method. On the condition of physiological pH, the results indicate that DNR prefers to form the 1:1 inclusion complex with gamma-CD. These results are further supported by infrared spectrometry (IR), and X-ray diffraction (XRD). An inclusion constant (K) for the formation of gamma-CD-DNR inclusion complex has been evaluated to be 9412.39 L mol(-1) from the absorbance changes. It is observed that the interaction mode between gamma-CD-DNR and DNA are a mixed binding, which contains partial intercalation and groove binding. The binding ratio of gamma-CD-DNR with DNA is n(gamma-CD-DNR):n(DNA) = 10:1, binding constant is K(295.15K)(circle minus) = 2.44 x 10(5) L mol(-1), enthalpy and entropy work as driven force in this action. Crown Copyright (C) 2010 Published by Elsevier Ltd. All rights reserved