Analysis of estrogenic compounds in Polygonum cuspidatum by bioassay and high performance liquid chromatography.

The estrogenic activity of traditional Chinese herb-Polygonum cuspidatum Sieb. et Zucc. was investigated by a recombinant yeast screening (YES) assay. Anthraquinones are the main components in the plant, of which emodin is the most abundant one. The ethyl acetate fraction of the ethanol extract of Polygonum cuspidatum was separated on a silica gel TLC plate and seven sub-fractions were collected. The results of bioassay demonstrated that Hzs1 and Hzs6 showed higher estrogenic activities than that of others and the potency of these two compounds were approximately 10(-4) g/L and 10(-3) g/L, respectively. HPLC analysis was performed to determine the activities and the active components. Combining the results of HPLC analysis and estrogenic activity test by YES led to the conclusion that an unknown bioactive compound might exist in the extraction of Polygonum cuspidatum.