Direct Flavonoid-Focused Chemical Comparison among Three Epimedium Plants by Online Liquid Extraction–High Performance Liquid Chromatography–Tandem Mass Spectrometry

Abstract

It is usually a tedious task to profile the chemical composition of a given herbal medicine (HM) using high performance liquid chromatography–tandem mass spectrometry (LC–MS/MS) due to the time-consuming sample preparation and laborious post-acquisition data processing procedures. Even worse, some labile compounds may face degradation risks when exposed to organic solvents for a relatively long period. As one of the most popular HMs, the promising therapeutic benefits of Epimedii Herba (Chinese name: Yinyanghuo) are well defined; however, the chemical profile, and in particular those flavonoids that have been claimed to be responsible for the efficacy, remains largely unknown. Attempts are devoted here to achieve direct LC–MS measurement and efficient post-acquisition data processing, and chemome comparison among three original sources of Epimedii Herba, such as Epimedium sagittatum (Esa), E. pubescens (Epu), and E. koreanum (Eko) was employed to illustrate the strategy utility. A home-made online liquid extraction (OLE) module was introduced at the front of the analytical column to comprehensively transfer the compounds from raw materials onto the LC–MS instrument. A mass defect filtering approach was programmed to efficiently mine the massive LC–MS dataset after which a miniature database was built involving all chemical information of flavonoids from the genus Epimedium to draw a pentagonal frame to rapidly capture potential quasi-molecular ions (mainly [M–H]−). A total of 99 flavonoids (66 in Esa, 84 in Eko, and 66 in Epu) were captured, and structurally annotated by summarizing the mass fragmentation pathways from the mass spectrometric data of authentic compounds and an in-house data library as well. Noteworthily, neutral loss of 144 Da was firstly assigned to the neutral cleavage of rhamnosyl residues. Significant species-differences didn’t occur among their chemical patterns. The current study proposed a robust strategy enabling rapid chemical profiling of, but not limited to, HMs.

Rapid characterization of chemical constituents in Naoling Pian by LC‐MS combined with data processing techniques

“…Taking peak 105 as an example, in the ESI + mode, the quasi‐molecular ion peak of m/z 839.2977 [M+H] + can be detected in the low collision energy mass spectrum with the retention time of 9.94 min. At the same time, high collision energy mass spectrometry showed that the main fragment ions were 677.2443 [M+H‐glc] + , 531.1879 [M+H‐glc‐rha] + , 369.1356 [M+H‐glc‐rha‐glc] + , it can be inferred that the compound may be Epimedin A1 [26–28]. This idea led to the characterization of 8 flavonoid glycosides, whose structures and the identification process, fragmentation pathway of Epimedin A1 based on QI are displayed in Figure 3.…”

Phytochemical Profile and Antioxidant Activities of Coleus amboinicus Lour. Cultivated in Indonesia and Poland

“…On the other hand, most of the detected compounds are not available for procurement and are present in minor amounts, which makes the isolation cost-inefficient. To overcome this, while still being able to use the data for relative comparisons between phytochemical profiles, one can use various approaches, such as fragmentation patterns [ 35 , 36 , 37 , 38 , 39 , 40 ], supported by a library search (used mainly in the present paper) or coupling (offline) to NMR spectroscopy [ 41 ]. The latter provides much more accurate structural information but is also less affordable and more laborious.…”

“…The LC–MS approach used in this study was based on the m / z -retention time pairs and normalized signals values to calculate the multivariate correlations and discrimination, an approach often used to compare plant samples within a taxon along with more advanced techniques [ 35 , 37 , 38 , 39 , 40 ], which allows compensating the lack of most phytochemical standards. Nonetheless, for absolute values, the standard-based quantification is advantageous.…”

Integrated strategy facilitates rapid in‐depth chemome characterization of traditional Chinese medicine prescriptions: Shengbai oral liquid as a case

“…Epimedii Folium was rich in flavonoids featured with isopentenyl substitution. After applying the empirical rules and referring to the information archived in the literature [24], a total of 70 flavonoids (Table S1) were tentatively characterized. In particular, four identities were justified by matching chromatographic and spectrometric information with authentic compounds, such as epimedium A, epimedin B, epimedin C, and baohuoside I.…”

“…After the harvest of a massive MS/MS dataset, the heavy workload subsequently turns to extracting valid information at the meanwhile of omitting the redundant information. In the past years, some meaningful post‐acquisition data processing strategies [22] have been proposed, such as neutral loss filtering [23], mass defect filtering [24], diagnostic fragment ion filtering [25], molecular weight imprinting [20] and mass tree filtering [26]. However, these approaches are still time‐consuming.…”