The comparison of the interaction between Epirubicin hydrochloride and Mitoxantron hydrochloride with calf thymus DNA by fluorescence spectroscopy and thermodynamic parameters

The interaction of calf thymus DNA with the Epirubicin hydrochloride and Mitoxantron hydrochloride under physiological condition was investigated by fluorescence spectroscopy. Epirubicin hydrochloride and Mitoxantron hydrochloride were purchased from sigma chemical co. The fluorescence spectroscopy was recorded on a Hittachi model F-2500 spectrophotometer (Japan). Regular decrease in fluorescence intensity of Mitoxantron hydrochloride is observed with increasing concentration of DNA, which means that DNA quenching the intrinsic fluorescence of Mitoxantron hydrochloride and also regular decrease in fluorescence intensity of DNA is observed with increasing concentration of Epirubicin hydrochloride. The binding force between a biomacromolecule and a small molecule mainly contains van der waals forces, hydrogen bonds, electrostatic force, and hydrophobic interaction. When ΔH < 0 or ΔH ≈ 0, ΔS > 0, the main binding force is electrostatic force; when ΔH < 0, ΔS < 0, the main binding force is van der waals force or hydrogen bond; when ΔH > 0, ΔS > 0, the main acting force is hydrophobic force. thermodynamic parameters obtained from vant hoff plot showed that vander walls and hydrogen bonding plays a major role in binding between Epirubicin hydrochloride and Mitoxantron hydrochloride with ct-DNA. All these results suggested that the binding mode of Epirubicin hydrochloride and Mitoxantron hydrochloride should be intercalate with the base pairs of ct-DNA.

Keywords:

Epirubicin hydrochloride , Fluorescence spectroscopy , Thermodynamic parameters , Mitoxantron hydrochloride , Calf thymus DNA