High-performance liquid chromatographic analysis of saponin compounds in Bupleurum falcatum

A mixture of saponin compounds (saikosaponin c, a, and d) in the 70% ethanol extract of a powdered sample of Bupleuri radix are analyzed by an Inertsil ODS-3 C18 column at a flow rate of 1.0 mL/min and detection wavelength of 203 nm. Well resolved chromatograms of saikosaponin c, a, and d are obtained with a gradient elution of acetonitrile-water from 40:60 (v/v) to 50:50 (v/v). The total time required for a single analysis is approximately 20 min. Calibration curves for saikosaponin c, a, and d are linear up to 2.5 mg/mL. The coefficient of variability values for saikosaponins in the extract are below 4%, and the recoveries for saikosaponin c, a, and dare 95.2 ± 1.1, 96.5 ± 0.9, and 96.2 ± 1.0%, respectively. The changes in saikosaponin contents for a two-year growth of Bupleurum falcatum are measured by the established high-performance liquid chromatography method.