Binding of flavanone with $\beta $-CD/ctDNA: a spectroscopic investigation

The inclusion complexation of flavanone with b-cyclodextrin was studied by ultraviolet absorption, steady state fluorescence, time-resolved fluorescence, and 2D ROESY nuclear magnetic resonance spectroscopic techniques. A 1:1 stoichiometric ratio was determined for the inclusion of flavanone with b-cyclodextrin. The Stern--Volmer constant for the accessible fraction of the binding of flavanone with b-cyclodextrin, and the binding constant for the flavanone--b-cyclodextrin complex are reported. The flavanone--b-cyclodextrin inclusion complex was characterized by 2D ROESY NMR spectroscopy. The binding of flavanone with ctDNA and the effect of b-cyclodextrin on the binding of flavanone to ctDNA were studied by absorption and fluorescence techniques. Binding constants are reported for the binding of flavanone with ctDNA and flavanone--b-cyclodextrin with ctDNA. The mode of binding of flavanone to DNA and formation of inclusion complex with b-cyclodextrin are proposed, supported by molecular modeling. The studies imply that b-cyclodextrin acts as carrier of flavanone for binding with DNA.