Simultaneous Determination of Nine Major Flavonoids in Sophora flavescens by RP-LC

A liquid chromatographic method was applied to determine trifolirhizin, kushenol K, kushenol L, kushenol N, kushenol X, kurarinone, norkurarinone, isokurarinone and kushenol A in the roots of Sophora flavescens, namely Kushen in China. The samples were separated on a YMC-C18 column (250 × 4.6 mm, 5 μm) with a gradient of methanol and 0.3% aqueous acetic acid (v/v) at a flow rate of 0.8 mL min−1 and detected at 295 nm. The complete separation was achieved within 45 min for the nine major flavonoids. All calibration curves expressed good linearity (r 2 > 0.999) within the test range. The recovery of this method was 92.3–106.9%. The assay was successfully applied to the quantification of nine flavonoids in 26 samples of Kushen. The results indicated that this developed LC assay could be readily utilized as a quality control method for the Chinese herb medicine Kushen.