Host-guest system of nimbin and beta-cyclodextrin or its derivatives: preparation, characterization, inclusion mode, and solubilization.

The inclusion complexation behavior, characterization, and binding ability of nimbin with beta-cyclodextrin (beta-CD) and its derivatives were investigated in both solution and the solid state by means of XRD, DSC, (1)H and 2D NMR, and UV-vis spectroscopy. The results showed that the water solubility and thermal stability of nimbin were obviously increased in the inclusion complex with cyclodextrins. This satisfactory water solubility and high thermal stability of the nimbin/CD complexes will be potentially useful for their application as herbal medicines or healthcare products.