Characterization and quantification of the chemical compositions of Scutellariae Barbatae herba and differentiation from its substitute by combining UHPLC–PDA–QTOF–MS/MS with UHPLC–MS/MS

The aim of this study was to investigate the possibility of using the non-official species Scutellaria indica L. as the substitute for the official species Scutellaria barbata D. Don. A sensitive, precise and accurate method was developed to identify their chemical compositions from the crude extracts using UHPLC-PDA-QTOF-MS/MS. 36 peaks were detected and 28 peaks have been tentatively and structurally characterized by comparing their retention times, UV spectra and HR-MS data with those of the reference substances and/or the data of the literatures. Additionally, 5 flavonoids have been quantified by multiple reaction monitoring (MRM) in the negative ionization mode. The results demonstrated that there were 23 common peaks between these two species. However, the other 13 peaks from S. barbata could not be detected in S. indica. Furthermore, the content of 5 flavonoids is significantly different. Scutellarein cannot be detected in S. indica, which was considered as the characteristic component for distinguishing the two species. Our data, therefore, clearly demonstrate that S. indica may not be used as the substitute for S. barbata and further investigation is needed to determine through investigation of their therapeutic efficacy.