Investigation of the inclusion behavior of HP-β-cyclodextrin with polydatin in solution and its analytical application

The inclusion complex of the slight water solubility, polydatin (PD), with hydroxypropyl-p-cyclodextrin (HP-beta-CD) was investigated for the first time in solution. The effect of HP-beta-CD on the spectral feature of PD was measured using fluorescence technique by varying the concentrations of HP-beta-CD. Meanwhile, the molecular mechanism of the formation of inclusion complex of PD with HP-beta-CD was studied and discussed by molecular modeling. The experimental result clearly indicated that the benzene ring of PD was encapsulated within the HP-beta-CD cavity to form a 1:1 stoichiometry host-guest compound. The apparent formation constants (K) was obtained by the typical double reciprocal plots and phase solubility studies. Due to the remarkable enhancement of the fluorescence intensity of PD, a spectrofluorimetric method was developed for the determination of PD in bulk aqueous solution in the presence of HP-beta-CD. The linear range was 2.00 x 10(-7)-2.00 x 10(-5) mol/L (r = 0.998) with the detection limit 9.50 x 10(-9) mol/L. The present study provided useful information for a more rational determination of PD in serum with recoveries of 97-104%. (C) 2012 Elsevier B.V. All rights reserved.