This study evaluated the effects of epimedium polysaccharide(EPS) on the solubility of icariin and baohuoside Ⅰ so as to preliminary explore its solubilization function and the underlying mechanism. The solubility of these two insoluble flavonoids in water and polysaccharide solutions was compared by high performance liquid chromatography, and the mechanism was investigated by diffe-rential scanning calorimetry(DSC) and critical micelle concentration determination. The results indicated that their solubilization in crude EPS solutions was concentration-dependent. The solubility of icariin and baohuoside Ⅰ in 20 mg·mL~(-1) EPS-1-1 was 9.05 times and 5.76 times that in water, respectively; while their solubility in 20 mg·mL~(-1) EPS-2-1 was 10.55 and 8.39 times that in water, respectively. The change of the DSC thermograms suggested the formation of new complexes from icariin and baohuoside Ⅰ with polysaccharides. The critical micelle concentrations proved the micellar properties of both EPS-1-1 and EPS-2-1. In short, EPS can significantly increase the solubility of icariin and baohuoside Ⅰ, the mechanism of which may be related to the formation of micellar complexes between EPS and insoluble flavonoids.
Keywords: Epimedium; baohuoside Ⅰ; icariin; mechanism; polysaccharide; solubility; solubilization.