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–β-cyclodextrin (HP–β-CD) was investigated for the first time in solution. The effect of HP–β-CD on the spectral feature of PD was measured using fluorescence technique by varying the concentrations of HP–β-CD. Meanwhile, the molecular mechanism of the formation of inclusion complex of PD with HP–β-CD was studied and discussed by molecular modeling. The experimental result clearly indicated that the benzene ring of PD was encapsulated within the HP–β-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–β-CD. The linear range was 2.00 × 10−7–2.00 × 10−5 mol/L (r = 0.998) with the detection limit 9.50 × 10−9 mol/L. The present study provided useful information for a more rational determination of PD in serum with recoveries of 97–104%.