Molecular modelling study for chiral separation of equol enantiomers by β-cyclodextrin

The intermolecular forces responsible for complexation of equol, a chiral molecule, with beta-cyclodextrin are determined using a molecular modelling study. The differential interactions between each enantiomer and the chiral host give rise to different configurations for the corresponding inclusion complexes which give rise to enantiodifferentiation. The van der Waals term is the main contributor to the total potential; however, the electrostatic term influences the enantioselectivity significantly since it establishes a difference between the most stable position of R- and S-equol and hence between their energies. A statistical analysis of the minimized energies is carried out to determine that R-equol is more retained than S-equol. (C) 1999 Elsevier Science B.V. All rights reserved.