Microcalorimetric and spectrographic studies on host–guest interactions of α-, β-, γ- and Mβ-cyclodextrin with resveratrol

Abstract

Thermal effects of inclusion processes of α-, β-, γ- and Mβ-cyclodextrin with resveratrol (RES) in aqueous solutions were determined by isothermal titration calorimetry (ITC) with nanowatt sensitivity at the temperature of 298.15 K. Standard enthalpy changes, stoichiometry and equilibrium constants of the inclusion complexes were derived from the direct calorimetric data utilizing nonlinear simulation. The thermodynamic parameters were discussed in the light of weak interactions between the host and the guest molecules combining with UV spectral message. The results indicate that all of the complexes formed in the aqueous solutions are in 1:1 stoichiometry. The binding processes of α-, β- and Mβ-cyclodextrin with the guest are mainly driven by enthalpy, while that of γ-cyclodextrin with the drug is driven by both enthalpy and entropy.