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

Authors: CHANDRASEKARAN SOWRIRAJAN, SAMEENA YOUSUF, MUTHU VIJAYAN ENOCH ISRAEL VIJAYARAJ

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

Keywords: Flavanone, \beta-cyclodextrin, fluorescence, ctDNA binding, 2D ROESY

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