Evaluation of quality of Radix Puerariae herbal medicine by isoflavonoids

OBJECTIVES: A high-performance liquid chromatography (HPLC) method was developed to examine five isoflavonoids present in Chinese herbal medicinal products containing Radix Puerariae. METHODS: Five isoflavonids, puerarin, daidzin, genistin, daidzein and genistein, were measured by HPLC. The HPLC system was equipped with an ODS-AM-303 column (250 mm x 4.6 mm i.d., 5 microm) and established gradient system comprising glacial acetic acid/water and glacial acetic acid/acetonitrile. KEY FINDINGS: The developed HPLC system yielded good separation of the five isoflavonoids. Relative coefficients of intraday and interday analysis of variation were less than 5%. The isoflavonoid recovery from Radix Puerariae was 90-113%. Most of the Radix Puerariae products studied contained five isoflavonoids in their HPLC fingerprint. The major component was purarine, then daidzin and daidzein; genistin and genistein were the least abundant. Five Radix Puerariae herbal medicines contained various concentrations of isoflavonoids. Of the 11 scientific extracted formulas of Radix Puerariae tested, ST brands had a greater isoflavonoid content than KA and SC brands. CONCLUSIONS: Separation and quantification of the five isoflavonoids by this HPLC method was suitable to assess the quality of Radix Puerariae herbal medicine products.