Quality evaluation of cortex moutan by high performance liquid chromatography coupled with diode array detector and electrospary ionization tandem mass spectrometry.

An high performance liquid chromatography (HPLC) coupled with diode array detector (DAD) and electrospray ionization tandem mass spectrometry (ESI/MS(n)) method was developed for quality evaluation of Cortex Moutan through identification of common constituents based on chromatographic fingerprints and determination of key pharmacological compounds. The representative chromatographic fingerprints of Cortex Moutan were obtained by analyzing 10 batches of samples under the optimized HPLC conditions and the results showed that the chromatographic profiles of the analyzed samples were very similar. Total of nineteen common peaks were detected and seventeen of them were identified rapidly by their characteristic UV profile and the information of molecular structure provided by ESI/MS(n) experiments. Simultaneously, five key pharmacological compounds, namely gallic acid, oxypaeoniflorin, paeoniflorin, benzoylpaeoniflorin and paeonol, were determined by the validated HPLC-DAD method. The linear calibration curves were acquired with correlation coefficients higher than 0.999. The precisions of intra-day and inter-day were not exceeding 3.1%, and the recoveries of five analytes were from 92.86 to 99.35%. This developed method that combined the chromatographic fingerprints and quantification assay ensured the phytoequivalence and pharmacological effects of Cortex Moutan and was successfully applied to the quality control of Cortex Moutan.