Simultaneous quantification of marker components in Ojeok-san by HPLC-DAD.

A systematic high-performance liquid chromatography-diode array detection (HPLC-DAD) method was developed for the rapid, accurate, and simultaneous quantification of eight marker compounds, paeoniflorin, 6-gingerol, decursin, glycyrrhizin, cinnamic acid, hesperidin, poncirin and magnolol, in Ojeok-san, a traditional Korean herbal medicine. These compounds were separated in less than 50 min using a Dionex C(18) column with a gradient elution system of water and methanol at a flow rate of 1 ml/min. All calibration curve of standard components showed excellent linearity (R(2) > 0.9922). Limits of detection (LOD) and limits of quantification (LOQ) ranged from 0.01 to 0.11 μg/ml and 0.03 to 0.34 μg/ml, respectively. The relative standard deviations (RSDs) of data of the intra- and inter-day experiments were less than 2.15 and 2.60%, respectively. The accuracy of recovery test ranged from 94.27 to 107.68% with RSD values 0.15-3.61%. The results of validation showed that the HPLC method was stable and very accurate for the quantification of eight marker components in Ojeok-san.