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

Properties of inclusion complexes between morin (M) and beta-cyclodextrin (beta CD), 2-hydroxypropyl-beta-cyclodextrin (HP beta CD) and Heptakis (2,6-O-di methyl) beta-cycloclextrin (DM beta CD) 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 A(L)-type. Also ORAC(FL). 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 DM beta CD the inclusion is primarily enthalpy-driven process meanwhile beta CD and HP beta CD are entropy-driven processes. This is corroborated by the different inclusion geometries obtained by 2D-NMR. (C) 2007 Elsevier B.V. All rights reserved.