Quality evaluation of Polygonum multiflorum in China based on HPLC analysis of hydrophilic bioactive compounds and chemometrics

Polygonum multiflorum is one of the most commonly used Chinese medicines. In this study, an effective pressurized water extraction and HPLC method was developed for first simultaneous determination of 8 hydrophilic compounds, including gallic acid, Hypaphorine, Catechin, Proanthocyanidin B1, Epicatechin, Proanthocyanidin B2, Emodin-8-O-β-d-glucopyranoside, stilbene glycosides, in P. multiflorum. The analysis was performed on a Zorbax SB-AQ column with gradient elution of 0.05% phosphoric acid aqueous solution and acetonitrile in 45 min. All calibration curves showed good linearity (R(2)>0.9994) within test ranges. The LOD and LOQ were lower than 0.2 and 1.0 μg/mL on column, respectively. RSD for intra- and inter-day of 8 analytes were less than 4.1% and 4.0%, respectively, and the overall recovery was 96.0-100.7%. The validated method was successfully applied to quantification of 8 hydrophilic compounds in samples of P. multiflorum from different locations of China. Chemometrics such as principal component analysis (PCA) and hierarchical clustering analysis (HCA) were used to evaluate homogeneity of P. multiflorum in China, which suggested that their quality homogeneity was good.