Identification and determination of the major constituents in traditional Chinese medicinal plant Polygonum multiflorum thunb by HPLC coupled with PAD and ESI/MS.

An HPLC-PAD-MS method has been developed for the qualitative and quantitative analysis of the major chemical constituents in Polygonum multiflorum Thunb. Chromatographic separation was conducted on an Alltima C18 column using water:acetonitrile:acetic acid as the mobile phase. Altogether nine compounds of various classes, including stilbene glucosides, anthraquinone glucosides and anthraquinone derivates, were identified by online ESI/MS. Their identities were ascertained by comparison with data derived from the literature and/or standard compounds. Five components were quantified by HPLC-PAD and the method was fully validated. All the linear regressions were acquired with R2 > 0.99 and the quantification limits (with a signal-to-noise ratio of 3) ranged from 0.63 and 1.57 ng. Repeatability was evaluated by intra- and inter-day assays and RSD value was within 2.47%. Recovery studies for the quantified compounds were found to be within the range 96.32-102.53% with RSD less than 2.35%. The overall procedure is rapid and reproducible and is considered suitable for qualitative and quantitative analysis of a large number of samples.