Binding of flavanone with β-CD/ctDNA: a spectroscopic investigation

The inclusion complexation of flavanone with β -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 β -cyclodextrin. The Stern–Volmer constant for the accessible fraction of the binding of flavanone with β -cyclodextrin, and the binding constant for the flavanone– β - cyclodextrin complex are reported. The flavanone– β -cyclodextrin inclusion complex was characterized by 2D ROESY NMR spectroscopy. The binding of flavanone with ctDNA and the effect of β -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– β -cyclodextrin with ctDNA. The mode of binding of flavanone to DNA and formation of inclusion complex with β -cyclodextrin are proposed, supported by molecular modeling. The studies imply that β -cyclodextrin acts as carrier of flavanone for binding with DNA.