Inclusion Complexation of Flavonoids with Cyclodextrin: Molecular Docking and Experimental Study

In our work, the inclusion ability and binding pattern of flavonoids (catechin, iso-liquiritigenin, luteolin, puerarin, rutin, and curcumin) with β-cyclodextrin (β-CD) and curcumin (CUR) with CDs (α-CD, β-CD, γ-CD, dimethyl-β-CD, Hydroxypropyl-β-CD, and glucosyl-β-CD) were studied by molecular docking. The results showed that CUR among the six flavonoids was more likely to form stable inclusion complexes with β-CD, and the HP-β-CD is the most suitable for CUR inclusion among the 6 types of CD. Phase solubility studies showed that CUR with β-CD or HP-β-CD, respectively, could form stable inclusion complexes in a stoichiometric ratio of 1 : 1. The CUR/β-CD and CUR/HP-β-CD inclusion complexes (ICs) were prepared by freeze-drying method. The successful preparation of IC was confirmed by SEM images, FT-IR spectra, and TG-DSC. The results of in vitro release showed that the release of CUR from IC prepared with β-CD or HP-β-CD could be improved significantly, and the release effect of HP-β-CD was better than that of β-CD. The inclusion with CD could be used to improve the solubility and bioavailability of CUR.