H-1-NMR NOE and molecular modelling to characterize thymol and carvacrol beta-cyclodextrin complexes

In this study the structural conformations of the complexes between beta-cyclodextrin and the geometrical isorners, thymol and carvacrol, were investigated using H-1-NMR and molecular modelling techniques. The NOE experiments were performed in aqueous solutions and showed the presence of only one complex with a well-defined orientation either for thymol or for carvacrol. Molecular modelling investigations were useful to clarify the structural conformation of the supramolecular edifice. To develop graphic simulations closer to the experimental conditions, the studies were performed in dynamic at 300 K with and without evaluating the dielectric constant, D. The best agreement of H-1-NMR NOE findings with the theoretical data was obtained after the evaluation of the dielectric constant parameter and these results confirmed the inclusion of thymol and carvacrol inside the beta CD hydrophobic cavity.