Reversed phase High Performance Liquid Chromatography used for the physicochemical and thermodynamic characterization of piceatannol/β-cyclodextrin complex

Piceatannol is one of resveratrol derivatives having health promoting potential. However, its low water-solubility and bioavailability could limit its use in both food and pharmaceutical fields. The aim of this work is the study of piceatannol complexation by beta-cyclodextrin (beta-CD) in aqueous media. The complex formed could improve the bioavailability, the solubility and the stability of piceatannol. The method used was based on RP-HPLC in which, beta-CD was added to methanol/water mixtures mobile phases. The apparent formation constant of piceatannol/beta-cyclodextrin complex was determined. Within the concentration interval studied (0-4 mM), whenever the concentration of beta-CD increased, retention time of piceatannol decreased; indicating an enhancement of solubility due to the formation of the piceatannol/beta-CD complex. The formation constants (K-F) of the piceatannol/beta-CD complex varied significantly with both the methanol concentration in the water-methanol mixture and the temperature. Moreover, in all the physicochemical conditions tested, the stoichiometry of piceatannol/beta-CD complex was 1:1. Finally, the thermodynamic parameters were determined: Delta G degrees = -13.123 kJ mol(-1), Delta H degrees = -33. 265 kJ mol(-1) and Delta S degrees = -67.559 J mol(-1) K-1. (C) 2013 Elsevier B.V. All rights reserved.