A Strategy for Identification and Structural Characterization of Compounds from Plantago asiatica L. by Liquid Chromatography-Mass Spectrometry Combined with Ion Mobility Spectrometry

Abstract

Plantago asiatica L. (PAL) as a medicinal and edible plant is rich in chemical compounds, which makes the systematic and comprehensive characterization of its components challenging. In this study, an integrated strategy based on three-dimensional separation including AB-8 macroporous resin column chromatography, ultra-high performance liquid chromatography–quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF MS), and ultra-high performance liquid chromatography-mass spectrometry with ion-mobility spectrometry (UHPLC-IM-MS) was established and used to separate and identify the structures of compounds from PAL. The extracts of PAL were firstly separated into three parts by AB-8 macroporous resin and further separated and identified by UHPLC-Q-TOF MS and UHPLC-IM-MS, respectively. Additionally, UHPLC-IM-MS was used to identify isomers and coeluting compounds, so that the product ions appearing at the same retention time (RT)can clearly distinguish where the parent ion belongs by their different drift times. UNIFI software was used for data processing and structure identification. A total of 86 compounds, including triterpenes, iridoids, phenylethanoid glycosides, guanidine derivatives, organic acids, and fatty acids, were identified by using MS information and fragment ion information provided by UHPLC-Q-TOF MS and UHPLC-IM-MS. In particular, a pair of isoforms of plantagoside from PAL were detected and identified by UHPLC-IM-MS combined with the theoretical calculation method for the first time. In conclusion, the AB-8 macroporous resin column chromatography can separate the main compounds of PAL and enrich the trace compounds. Combining UHPLC-IM-MS and UHPLC-Q-TOF MS can obtain not only more fragments but also their unique drift times and RT, which is more conducive to the identification of complex systems, especially isomers. This proposed strategy can provide an effective method to separate and identify chemical components, and distinguish isomers in the complex system of traditional Chinese medicine (TCM).

Phytochemical Profiling by UPLC‐ESI‐QTOF‐MS of Kalaharia uncinata (Schinz) Moldenke, Widely Used in Traditional Medicine in DR Congo

“…Thus, based on LC/MS data, compound 1 was tentatively identified as caffeic acid-O-deoxyhexosylhexoside. (44 Da) and cleavage of a hexose (hex) moiety (162 Da), corresponding to the fragmentation behavior of iridoids [19][20][21] (S4, Supplementary Information). The mass spectrum observed in the AcOEt fraction exhibited fragment ions at m/z 193 [MÀ Hhex-H 2 O] À and 149 [MÀ H-hex-H 2 OÀ CO 2 ] À , that matched with geniposidic acid or secologanic acid.…”

“…The fragmentation patterns of verbascoside, [39] are presented in S7 (Supplementary information). According to their different Rt and references, [20,62] compound 11 which eluted first was identified as acteoside and compound 13 which eluted second as isoverbascoside. [20,54,55] The observed fragments do not correspond with those provided in literature.…”

“…Compound 3 ( m/z 373.1135 [M−H] − ) detected in all extracts, eluted at Rt 3.94 and corresponded to a molecular formula C 16 H 22 O 10 . It was characterized by losses of H 2 O (18 Da), CO 2 (44 Da) and cleavage of a hexose (hex) moiety (162 Da), corresponding to the fragmentation behavior of iridoids [19–21] (S4, Supplementary Information). The mass spectrum observed in the AcOEt fraction exhibited fragment ions at m/z 193 [M−H‐hex‐H 2 O] − and 149 [M−H‐hex‐H 2 O−CO 2 ] − , that matched with geniposidic acid or secologanic acid [19,22–24] .…”

Rapid chemical characterization of Danggui Buxue decoction using processed Astragali Radix and Angelicae Sinensis Radix based on diagnostic ion and molecular network

“…In recent years, studies on the chemical composition of TCM had combined multilevel high‐resolution MS and online energy‐resolved MS to distinguish isomers with the same fragment ions and some differences in fragment relative abundance using different compounds with different on‐line collision energy (OCE) (Tang et al, 2021). Alternatively, MS with offline NMR, 1D‐NMR, and 2D‐NMR, and ion mobility MS could also be used to identify substances without reference standards (Gao et al, 2022; Nöst et al, 2021; Wang et al, 2016). It was obvious that the combination of multiple techniques could identify more compounds.…”

Study of phytochemical compounds of Plantago major leaves grown in Kazakhstan

“…Previous studies of the phytochemical composition of other Plantago species revealed similar components to those found in Plantago major, such as phenol, benzofuran, Diglycerol, various kinds of acids etc. (Jamilah et al 2012;Gao et al 2022).…”