Water-soluble inclusion complexes of trans-polydatin by cyclodextrin complexation: Preparation, characterization and bioactivity evaluation

The inclusion complexes of trans-polydatin (PD) with β-CD and γ-CD were prepared. The inclusion complexation behavior, characterization and interactions of PD with CDs were investigated in both the solution and the solid state by means of UV-vis, ESI-MS, NMR, FT-IR, XRD, SEM, TG and DSC. All of the characterization information demonstrated the formation of PD/CDs inclusion complex, and the PD/CDs inclusion complexes exhibited different spectroscopic features and properties from PD. The 1:1 stoichiometry of the complexes was visually proven with the ESI-MS experiment and Job's method. Meanwhile, it was the phenyl group (a and b rings) of the PD molecule that were included in the CDs cavity from the wide side. Moreover, the water solubility of PD/CDs was significantly improved from 0.161 mg/mL to 7.21 mg/mL (PD/β-CD) and 12.02 mg/mL (PD/γ-CD). Consequently, the bioavailability of PD/CDs inclusion complexes were effectively improved over free PD in vitro. The present study provides useful information for the potential application of complexation with PD, a naturally occurring hydrophobic polyphenolic compounds herbal medicine.