Characterization and discrimination of raw and vinegar‐baked Bupleuri radix based on UHPLC‐Q‐TOF‐MS coupled with multivariate statistical analysis

Abstract

Bupleuri Radix is a commonly used herb in clinic, and raw and vinegar-baked Bupleuri Radix are both documented in the Pharmacopoeia of People's Republic of China. According to the theories of traditional Chinese medicine, Bupleuri Radix possesses different therapeutic effects before and after processing. However, the chemical mechanism of this processing is still unknown. In this study, ultra-high-performance liquid chromatography with quadruple time-of-flight mass spectrometry coupled with multivariate statistical analysis including principal component analysis and orthogonal partial least square-discriminant analysis was developed to holistically compare the difference between raw and vinegar-baked Bupleuri Radix for the first time. As a result, 50 peaks in raw and processed Bupleuri Radix were detected, respectively, and a total of 49 peak chemical compounds were identified. Saikosaponin a, saikosaponin d, saikosaponin b , saikosaponin e, saikosaponin c, saikosaponin b , saikosaponin b , 4''-O-acetyl-saikosaponin d, hyperoside and 3',4'-dimethoxy quercetin were explored as potential markers of raw and vinegar-baked Bupleuri Radix. This study has been successfully applied for global analysis of raw and vinegar-processed samples. Furthermore, the underlying hepatoprotective mechanism of Bupleuri Radix was predicted, which was related to the changes of chemical profiling.

Localization of malonyl and acetyl on substituted saikosaponins according to the full‐scan mass spectra and the fragmentation of sodium‐adduct ions in the positive mode

“…Bioanalysis of saikosaponins has also been reported by LC/MS/MS in the biosamples of animals after administration . Besides the determination of saikosaponins with reference standards, characterization and identification of saikosaponins in the absence of reference standards and even the unknowns in the extracts of Bupleurum species have been reported according to the mass fragmentation in the negative mode using LC/MS n . In these reports, substituted saikosaponins, with malonyl and acetyl moieties in most cases, were characterized by sequential loss of substituents, such as CO 2 and C 3 H 2 O 3 for malonyl and C 2 H 2 O for acetyl, and sugar units in the MS n spectra in the negative mode .…”

A rapid classification and identification method applied to the analysis of glycosides in Bupleuri radix and liquorice by ultra high performance liquid chromatography coupled with quadrupole time‐of‐flight mass spectrometry

“…In the positive‐ion mode, the fragment ion information was m/z 781 [M+H] + , m/z 763 [M+H‐H 2 O] + , m/z 619 [M+H‐C 6 H 10 O 5 ] + , m/z 473 [M+H‐C 6 H 10 O 5 ‐C 6 H 10 O 4 ] + , m/z 441 [M+H‐C 6 H 10 O 5 ‐C 6 H 10 O 4 ‐CH 3 OH] + , and m/z 455 [M+H‐C 6 H 10 O 5 ‐C 6 H 10 O 4 ‐H 2 O] + . According to the above rule, the compound was determined to be saikosaponins (type 1) on the basis of CF at m/z 619 [M+H‐C 6 H 10 O 5 ] + , while the fragment ion at m/z 441 [M+H‐C 6 H 10 O 5 ‐C 6 H 10 O 4 ‐CH 3 OH] + indicated the loss of CH 3 OH (CNL of type 1), based on the fragment peaks and the literature, it was speculated to be saikosaponin D . The possible fragment pathway is shown in Figure .…”

“…For type II compounds, the DNL was CH 2 CO (42 Da), resulting from an acetyl group in the structure; however, type III tended to produce C 3 H 2 O 3 (86 Da) on the basis of malonyl group. In short, all saikosaponins were able to be identified rapidly by CF and NL (CNL and DNL) [20][21][22][23][24][25].…”

“…Aglycons were produced because of the sequential loss of Glc and Fuc, then, the aglycon lost CH 3 OH (32 Da) and, typically, a molecule of water. In the positive-ion mode, 3 OH] + indicated the loss of CH 3 OH (CNL of type 1), based on the fragment peaks and the literature, it was speculated to be saikosaponin D [20][21][22]. The possible fragment pathway is shown in Figure 3.…”

Z0 ion from saikosaponins with 16 α‐OH and Y0‐H2O from saikosaponins with 16 β‐OH may underlie their different dissociation patterns of [aglycone − H2O + H]+

“…To improve the quality control of Radix Bupleuri and its pharmaceutical preparations, the characterization and identification of saikosaponins in herbs have been reported based on their fragmentation patterns using liquid chromatography/mass spectrometry (LC/MS) in combination with their UV absorption and retention time (t R ) . In these reports, the types and linkage sequences of sugars in the glycosyl part on the saikosaponins were clarified clearly by multi‐stage mass spectrometry (MS n ) in the negative ion mode.…”