Studying on inclusion complexes of Wogonin with β-cyclodextrin and hydroxypropyl-cyclodextrin

The formation of the complexes of Wogonin with β-cyclodextrin (β-CD) and hydroxypropyl-cyclodextrin (HP-β-CD) was studied by fluorescence spectra and nuclear magnetic resonance spectroscopy (NMR). The formation constants (Ks) of complexes were determined by fluorescence method. The results suggested that HP-β-CD was easier to form inclusion with Wogonin than β-CD in solution. In different pH solutions, CDs have different inclusive capacity to Wo. β-CD was most suitable for inclusion of neutral form and HP-β-CD was suitable for acidic form. In addition, the experimental resulted confirmed the existence of 1:1 inclusion complex of Wogonin with CDs.Besides, kinetic studies of DPPH with Wogonin and CDs complexes were done. The results obtained indicated that the complex was the most reactive form. Special configuration of complex has been proposed on NMR technique.

The formation of the complexes of Wogonin with β-cyclodextrin (β-CD) and hydroxypropyl-cyclodextrin (HP-β-CD) was studied by different methods, and special configuration of complex has been proposed.Figure optionsDownload as PowerPoint slideHighlights
► The present study has demonstrated the inclusion complex interaction between Wogonin with β-CD and HP-β-CD.
► Among the CDs examined, β-CD was most suitable for inclusion of neutral form and HP-β-CD was suitable for acidic form.
► The activity of eliminating free radical DPPH
• were inclusion complexes > free Wogonin.
► The fluorescence spectroscopy and 1H NMR data have shown the formation of a stable 1:1 stoichiometri complex.
► Moreover, a mechanism was set up to expound the structure of the inclusion complexes.