An investigation into the preparation, characterization and antioxidant activity of puerarin/cyclodextrin inclusion complexes

The inclusion complexes between puerarin and three cyclodextrins (CDs), namely β-cyclodextrin (β-CD), (2-hydroxy)propyl-β-cyclodextrin (HP-β-CD, DS = 4.2) and methyl-β-cyclodextrin (Me-β-CD, DS = 12.5) were prepared. The effects of the complexation on the stability of puerarin were investigated in both solution and the solid state by methods of phase solubility study, XRD, DSC and SEM. Furthermore, the antioxidant activities of puerarin and puerarin/CDs inclusion complexes were determined by reducing power and 1,1-diphenyl-2-picryl-hydrazyl methods. Results showed that puerarin formed 1:1 stoichiometric inclusion complexes with β-CD, HP-β-CD and Me-β-CD. Additionally, the solubility and thermal stability of puerarin was improved after encapsulating by CDs. Antioxidant activity studies showed that the antioxidant performance of the inclusion complex was better than the native puerarin, and puerarin/Me-β-CD complex was the most effective form. It can be a potentially promising way to develop a new formulation of puerarin for herbal medicine or healthcare products.