Rapid discrimination of Notopterygium incisum and Notopterygium franchetii based on characteristic compound profiles detected by UHPLC-QTOF-MS/MS coupled with multivariate analysis.

Introduction The herbs Notopterygium incisum (NI) and N. franchetii (NF) are referred to as "Qianghuo" in the Chinese Pharmacopeia and are popular for treatment of certain conditions, including headaches, rheumatoid arthritis and the common cold. Recently, several adulterations of NI and NF have been found in the Chinese herbal market. Objective The aim of this study was to rapidly identify the unique characteristic compounds of NI and NF, to discriminate Qianghuo from its adulterations. Methodology Twenty-four batches of NI and NF samples with different origins were collected and extracted with methanol. The extracts were analysed using ultrahigh-performance liquid chromatography-quadrupole time-of-flight tandem mass spectrometry (UHPLC-QTOF-MS/MS). Principal component analysis (PCA) and orthogonal partial squared discriminant analysis (OPLS-DA) were then used to distinguish between NI and NF and to identify their potential characteristic markers. Results Fifty compounds were identified or tentatively characterised according to the retention time, m/z value and MS/MS fragment analysis. Six compounds were selected as potential markers of NI and NF by PCA and OPLS-DA. They were successfully applied to authenticate 17 kinds of Chinese patent medicines containing Qianghuo. The markers could not be detected in three of the Chinese patent medicines, indicating that they were counterfeit products. Conclusion The UHPLC-QTOF-MS/MS coupled with the multivariate analysis method could discriminate NI and NF from their adulterations. Moreover, the data clearly demonstrated significant differences in the chemical compositions of NI and NF. Further research is needed to examine the relationship between therapeutic efficacy and the chemical constituents of NI and NF.