Development and Validation of an HPLC–PDA Method for Quality Control of Jwagwieum, an Herbal Medicine Prescription: Simultaneous Analysis of Nine Marker Compounds

<b>Background/Objectives</b>: Jwagwieum (or Joa-Gui Em; JGE) consists of six herbal medicines, <i>Rehmannia glutinosa</i> (Gaertn.) DC., <i>Dioscorea japonica</i> Thunb., <i>Lycium chinense</i> Mill., <i>Cornus officinalis</i> Siebold & Zucc., <i>Poria cocos</i> Wolf, and <i>Glycyrrhiza uralensis</i> Fisch., and has been widely used to treat kidney-yin deficiency syndrome. In the present study, a high-performance liquid chromatography with photodiode array detector (HPLC-PDA) method for the simultaneous quantification of the nine components, i.e., gallic acid, 5-(hydroxymethyl)furfural, morroniside, loganin, liquiritin apioside, liquiritin, ononin, glycyrrhizin, and allantoin, was developed. <b>Methods</b>: The developed HPLC-PDA assay for quality control of JGE was validated with respect to linearity, limit of detection (LOD), limit of quantification (LOQ), recovery, and precision. <b>Results</b>: In the regression equation of the calibration curve, the coefficient of determination was ≥0.9980, and LOD and LOQ were 0.003-0.071 μg/mL and 0.010-0.216 μg/mL, respectively. Recovery and precision (relative standard deviation) were 96.36-106.95% and <1.20%, respectively. In this analytical method, nine compounds were detected at concentrations of 0.15-3.69 mg/lyophilized gram. <b>Conclusions</b>: The developed and validated analytical method could be used to obtain basic data for the quality control of JGE and related herbal prescriptions.