Inclusion complexes of phosphorylated daidzein derivatives with β-cyclodextrin: Preparation and inclusion behavior study

In the present work the feasibility of β-cyclodextrin in complexation was explored, as a tool for improving the solubility and biological ability of daidzein derivatives. A series of phosphorylated daidzein derivatives featuring different chain lengths were synthesized through a modified Atherton–Todd reaction and their inclusion complexes with βCD were prepared by coprecipitation method. The inclusion complexation behavior was studied by fluorescence, UV, FT-IR, MS and 1H NMR. The results showed that only phosphorylated daidzein derivative carrying small substituent group ((C2H5O)2PO) entered the cavity of βCD and formed 1:1 inclusion complex. The formation constant was 175 (mol/L)−1.

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► Phosphorylated daidzein derivatives featuring different chain lengths were synthesized.
► Their inclusion complexes with CD were prepared by coprecipitation method.
► The inclusion behavior was studied by fluorescence, UV, FT-IR, MS and NMR.
► The results showed that only daidzein derivative 3a entered the cavity of CD.
► 1:1 inclusion was formed and the formation constant was 175 (mol/L)−1.