Research on flavonoids contents in Fructus sophorae with capillary zone electrophoresis.

Genistin, genistein, kaempferol, quercetin and rutin, five kinds of flavonoids in Fructus sophorae, have been analyzed by capillary zone electrophoresis with internal standard calibration. Buffer pH and concentration, applied voltage, ß-cyclodextrin and ethanol concentration were optimized and the optimum conditions are: 20 mmol/L borax (pH 9.5) with 8 mmol/L ß-cyclodextrin and 5% (v/v) ethanol and at a voltage of 25 kV. The contents of five flavonoids in Fructus Sophorae grown in different area of Dezhou, Shandong Province of China were determined by the developed method and with satisfactory results. The distributions of the studied flavonoids were also investigated.