Complexation of morin with three kinds of cyclodextrin. A thermodynamic and reactivity study

Abstract

Properties of inclusion complexes between morin (M) and β-cyclodextrin (βCD), 2-hydroxypropyl-β-cyclodextrin (HPβCD) and Heptakis (2,6-O-di methyl) β-cyclodextrin (DMβCD) such as aqueous solubility and the association constants of this complex have been determined. The water solubility of morin was increased by inclusion with cyclodextrins. The phase-solubility diagrams drawn from UV spectral measurements are of the AL-type. Also ORACFL studies were done. An increase in the antioxidant reactivity is observed when morin form inclusion complex with the three cyclodextrin studied. Finally, thermodynamics studies of cyclodextrin complexes indicated that for DMβCD the inclusion is primarily enthalpy-driven process meanwhile βCD and HPβCD are entropy-driven processes. This is corroborated by the different inclusion geometries obtained by 2D-NMR. © 2007 Elsevier B.V. All rights reserved.