Simultaneous determination of five saponins in Bupleuri Radix by HPLC-DAD dual wavelength method

Abstract

Epoxy ether type and isophthalene type saponin are the main saponins of Bupleurum chinense. However,due to the difference of their UV spectrum,there is no quantitative method for simultaneous determination of these two kinds of saponins. In this paper,a dual-wavelength high performance liquid chromatography(HPLC) was developed for simultaneous determination of five saponins in epoxidized ether(saikosaponin a,c,d) and isosorbide type(saikosaponin b1,b2). The mobile phase was eluted with acetonitrile-water(0.1% phosphoric acid) gradient at a column temperature of 30 °C and a flow rate of 1.0 mL·min⁻¹. The detection wavelengths were 208 nm for saikosaponins a,c, and d, and 254 nm for saikosaponins b₁ and b₂. The results showed that the separation of five kinds of saikosaponin was good, with the linear range of 9.70-1 935.00(r=0.999 4),8.20-1 380.00(r=0.999 3),6.90-1 640.00(r=0.999 0),5.25-630.00(r=0.999 4), and 5.15-618.00 mg·L⁻¹(r=0.999 5), respectively. The average recoveries were 97.70%-100.2% and the RSD was less than 3%(n=6). The method is simple,rapid and reproducible. It can be used for the determination of five kinds of saikosaponins in B. chinense.