Qualitative and quantitative simultaneous determination of six marker compounds in soshiho-tang by HPLC-DAD-ESI-MS

Soshiho-tang, one of the herbal prescriptions, has been used in treatment of chronic liver disease. In this study, the efficient high-performance liquid chromatography coupled with diode array detection and electrospray ionization tandem mass spectrometry (HPLC-DAD-ESI-MS) method was developed and validated for simultaneous determination of six marker compounds, namely homogentisic acid, baicalin, glycyrrhizin, saikosaponin A, 6-gingerol and ginsenoside Rg3 in Soshiho-tang. The analysis of six marker compounds was carried out using a C₁₈ column (SHISEIDO S-5 μm, 4.6 mm I.D. × 250 mm) and gradient elution with water ? 0.1% trifluoroacetic acid and acetonitrile. The analytical method was validated for linearity, precision and accuracy. Calibration curve for six marker compounds showed good linear regression (r² > 0.9996). The limits of detection (LOD) and limits of quantification (LOQ) for analytes were ranged from 0.04 to 0.16 μg/mL and 0.12 to 0.47 μg/mL, respectively. The relative standard deviations (RSD%) of the precision test, intra- and inter-day, were less than 0.32% and 0.10%, respectively. All recoveries of the six marker compounds were ranged from 100.05% to 102.25% with RSD less than 0.63%. These results have shown that this developed method was efficient for the quality evaluation of Soshiho-tang.