Integrated Strategy Drives Direct Infusion-Tandem Mass Spectrometry as an Eligible Tool for Shotgun Pseudo-Targeted Metabolomics of Medicinal Plants.

Direct infusion (DI) has an extraordinary high-throughput advantage. Pseudo-targeted metabolomics (PTM) has been demonstrated integrating the merits of both nontargeted and targeted metabolomics. Herein, we attempted to implant DI into the PTM concept to configure a new strategy allowing shotgun PTM. First, a versatile MS/MSALL program was applied to acquire MS1 and MS2 spectra. Second, online energy-resolved MS (online ER-MS) was conducted to obtain breakdown graph as well as optimal collision energy (OCE) for each ion transition paired by precursor ion and the dominant product ion. Third, selected reaction monitoring (SRM) was responsible to output a quantitative dataset with a constant length. Moreover, breakdown graph also served as orthogonal structural evidence when matching MS2 spectra between DI-MS/MS and an in-house library to strengthen structural annotation confidence. To evaluate and illustrate the utility of the new strategy toward shotgun PTM of medicinal plants, in-depth chemome comparison was conducted within three Cistanche species, all of which are edible medicinal plants and playing essential roles for turning the deserts into the oases. A total of 185 variables participated in the quantitative measurement program. Each diagnostic ion pair was featured with an OCE. Significant species differences occurred, and echinacoside, acteoside, isoacteoside, 2'-acetyl-acteoside, tubuloside B, mannitol, sucrose, betaine, malate, as well as choline were found to be confirmative chemical markers offering primary contributions toward the species discrimination. After cross-validation with LC-MS/MS, DI-MS/MS fortified with the new strategy is an eligible tool for shotgun PTM, beyond Cistanche plants.

[Rapid chemome profiling of Cistanche salsa using DI-MS/MS~(ALL)].

The current study aims to rapidly and comprehensively profile the chemical composition of Cistanche salsa using direct infusion coupled with MS/MS~(ALL)(DI-MS/MS~(ALL)). The C. salsa extract was directly imported into electrospray ionization(ESI) source of quadrupole time-of-flight(Q-TOF) mass spectrometer with an infusion pump at a flow rate of 10 µL·min~(-1). Acquisition program was applied under negative ionization polarity to collect one MS~1 spectrum(m/z 50-1 200), followed by 1 150 MS~2 spectra with precursor isolation window(m/z 1) amongst mass range m/z 50-1 200. After each MS~2 spectrum was matched to its precursor ion, putative identification was conducted through matching mass spectral data with literature and database. A total of 31 components were identified from C. salsa, including 9 phenylethanoid glycosides, 2 iridoids, 4 saccharides, 9 organic acids, and 7 other compounds, similar to those from C. tubulosa and C. deserticola. In conclusion, DI-MS/MS~(ALL), a facile and reliable analytical tool, can be employed for qualitative analysis of chemical constituents in C. salsa. The research offers a promising strategy to achieve rapid chemome profiling of herbal medicine and provides an alternative source of Cistanches Herba.

[Rapid chemome profiling of chemical components of Lonicerae Japonicae Flos using DI-MS/MS~(ALL)].

A new method of MS/MS~(ALL) was designed to sequentially record a MS~2 spectrum at each unit mass window through gas phase fractionation concept, so as to offer an opportunity for universal MS~2 spectral recording with direct infusion(DI). As a proof-of-concept, DI-MS/MS~(ALL) was applied for rapid chemome profiling of a famous herbal medicine named Lonicerae Japonicae Flos. After each MS~2 spectrum was correlated to its precursor ion, the structural annotation was conducted by applying well-defined mass cracking rules, matching the mass spectral data with literatures and referring to those accessible databases. As a result, a total of 54 components were identified from Lonicerae Japonicae Flos extract, including 21 phenolic acids, 13 flavonoids, 12 iridoids, 4 triterpenoids and 4 other compounds. Therefore, DI-MS/MS~(ALL) is a powerful tool for comprehensive, rapid qualitative analysis of chemical profiles of traditional Chinese medicine and other chemical components of complex systems.

[Chemome profiling and comparison of three Orobanche medicinal plants].

Several Orobanche medicinal plants sometimes served as alternative sources of Cistanches Herba, attributing to the benefits such as tonifying kidney, strengthening tendons and bones. Among them, O. coerulescens, O. cernua and O. pycnostachya have been widely utilized in northern China for treatments of pains in the loins and knees, impotence, and spermatorrhea. However, their chemical profiles haven't been elucidated. In the present study, UHPLC-IT-TOF-MS was implemented to conduct in-depth chemome profiling of O. coerulescens, O. cernua and O. pycnostachya, aiming to achieve a comprehensive chemical characterization and to provide pronounced information for the quality control and clinical applications. An ACE Ultra-Core 2.5 Super C_(18)(3.0 mm×150 mm, 2.5 µm) column was deployed for chromatographic separations, and high-resolution MS~n spectra were recorded by IT-TOF-MS. Forty-eight components, in total, were observed, and thirty-eight ones were structurally annotated according to proposing mass fragmentation patterns, matching with relevant databases. Particularly, nine ones were confirmed by reference compounds. Overall, the chemical compositions of O. coerulescens and O. cernua are quite similar, and differences occur between O. pycnostachya and the prior two ones; primary chemical family is phenylethanoid glycosides, and several lignan glycosides as well as iridoid glycosides are also observed; the primary components include acteoside, isoacteoside, crenatoside and 2'-acetylacteoside, etc.

Serially coupled column liquid chromatography: An alternative separation tool.

Despite the rapid development of liquid chromatography (LC) in recent decades, it remains a challenge to achieve the desired chromatographic separation of complex matrices using a single column. Multi-column LC techniques, particularly serially coupled column LC (SCC-LC), have emerged as a promising solution to overcome this challenge. While more attention has been focused on heart-cutting or comprehensive two-dimensional LC, reviews specifically focusing on SCC-LC, which offers advantages in terms of precision and facile instrumentation, are scarce. Here, our concerns are devoted to the progress summary regarding the instrumentation and applications of SCC-LC. Emphasis is placed on column selection aiming to enlarge peak capacity, selectivity, or both through the optimization of combination types (e.g. RPLC-RPLC, -RPLC-HILIC, and achiral-chiral LC), connection devices (e.g. zero dead volume connector, tubing, and T-type connector), elution program (i.e. isocratic or gradient) and detectors (e.g. mass spectrometer, ultraviolet detector, and fluorescence detector). The application of SCC-LC in pharmaceutical, biological, environmental, and food fields is also reviewed, and future perspectives and potential directions for SCC-LC are discussed. We envision that the review can give meaningful information to analytical scientists when facing heavy chromatographic separation tasks for complicated matrices.

MS/MS fingerprint comparison between adjacent generations enables substructure identification: Flavonoid glycosides as cases.

MS/MS spectrum matching currently serves as a favored means to identify the concerned metabolites attributing to the accessibility of several famous databases. However, the rule that takes the entire structure into account frequently leads to "0 hit" when inquiring MS/MS (usually MS2) spectrum in the databases. Conjugation plays an important role for the high-level structural diversity of metabolites in all organisms, and a given conjugate usually consists of two or more substructures. If MS3 spectra participate in database retrieval, the structural annotation potential of those databases should be dramatically expanded via identifying substructures. Attributing to the ubiquitous distribution pattern, flavonoid glycosides were deployed as the representative family to justify whether the primary fragment ion termed as Y0+, resulted from neutral loss of glycosyl residue(s), generated identical MS3 spectrum with MS2 spectrum of the aglycone cation namely [A+H]+. Because of owning unique ability to measure MS/MS spectrum with the exactly desired exciting energy, linear ion trap chamber of Qtrap-MS was responsible for generating the desired MS3 and MS2 spectra. When taking both m/z and ion intensity features into consideration, the findings included: 1) glycosides sharing identical aglycones produced the same MS3 spectra for Y0+; 2) different MS3 spectra for Y0+ occurred amongst glycosides bearing distinct, even isomeric, aglycones; 3) isomeric aglycones generated different MS2 spectra; and 4) MS3 spectra for Y0+ agreed with MS2 spectra of [A+H]+ when comparing paired glycoside and aglycone. Together, fingerprint comparison between MS3 and MS2 spectra could structurally annotate the substructures and further advance MS/MS spectrum matching towards the identification of, but not limited to, aglycones for flavonoid glycosides.

Two-dimensional code enables visibly mapping herbal medicine chemome: an application in Ganoderma lucidum.

BACKGROUND: Chemical profile provides the pronounced evidence for herbal medicine (HM) authentication; however, the chemome is extremely sophisticated. Fortunately, two-dimensional (2D) code, as a quick response means, is conceptually able to store abundant information, exactly fulfilling the chemical information storage demands of HMs. METHODS: We here attempted to denote both MS[Formula: see text] and MS[Formula: see text] dataset of HM with a single 2D-code chart. Measurement of Ganoderma lucidum that is one of the most famous HMs with LC-MS/MS was employed to illustrate the "coding-decoding" workflow for the conversion amongst MS/MS dataset, 2D-code, and chemical profile, and to evaluate the applicability as well. After data acquisition, and m/z value of each deprotonated molecular signal was divided into integer and decimal portions, corresponding to x and y coordinates of 2D-plot, respectively. On the other side, m/z values of all its fragment ions were exactly assigned to serial x values sharing an identical y value being equal to the precursor ion. 2D-code was thereafter produced by plotting these defined dots at a 2D-chart. Regarding a given 2D-code map, the entire chart (x coordinate: 0-600; y coordinate: 0-600) was fragmented into two regions by the line of y=x. MS[Formula: see text] spectral signals always located below the line, whereas all fragment ions lay at the left zone. After extracting information from the edges of each square frame, m/z values of both precursor ion and fragment ions could be harvested and putatively deciphered to a compound through applying some empirical mass fragmentation rules. RESULTS: The entire code of Ganoderma lucidum fruit bodies therefore corresponded exactly to a compound set. The elution program, even the employment of direct infusion, couldn't significantly impact the code, and dramatical differences occurred between different species and amongst different parts of Ganoderma lucidum as well. Not only ganoderic acid cluster but also certain primary metabolites served as the diagnostic compounds towards species differentiation. CONCLUSION: 2D-code might be a meaningful, practical visual way for rapid HM recognition because it is convenient to achieve the conversion amongst MS/MS dataset, 2D-barcode plot, and the chemome.

Quality structural annotation for the metabolites of chlorogenic acid in rat.

Chlorogenic acid (CA) serves as a principal contributor for the health benefit spectrum of tea; however, its metabolism pattern hasn't been completely clarified. We attempted here to profile CA metabolism through fortifying isomer identification ability onto LC-MS/MS. Online energy-resolved MS was applied to configure full collision energy ramp-MS2 spectrum. Quantum structural calculation was undetaken to pursue the relationships between chemical structures and optimal collision energy/the maximum relative ion intensity. Thirty-seven metabolites were captured in biological matrices. Plausible structures were configured by applying the empirical mass fragmentation rules to m/z values and the summarized relationships were utilized to drive the plausible structures to confidence-enhanced identities. Hydrolysis, glucuronidation, sulfation, acyl migration, oxidation, and hydrogenation occupied primary metabolism channels. Together, the current study disclosed in depth the metabolism profile of CA and moreover, suggested a versatile analytical route for quality metabolite identification.

Rapid tryptic peptide mapping of human serum albumin using DI-MS/MSALL.

In recent decades, proteinic drugs, in particular monoclonal antibodies, are taking the leading role of small molecule drugs, and peptide mapping relying on liquid chromatography-tandem mass spectrometry (LC-MS/MS) is an emerging approach to substitute the role of a ligand-binding assay for the quality control of the proteinic drugs. However, such LC-MS/MS approaches extensively suffer from time-intensive measurements, leading to a limited throughput. To achieve accelerated measurements, here, the potential of DI-MS/MSALL towards tryptic peptide mapping was evaluated through comparing with well-defined LC-MS/MS means, and human serum albumin (HSA) was employed as the representative protein for applicability illustration. Among the 55 tryptic peptides theoretically suggested by Skyline software, 47 were successfully captured by DI-MS/MSALL through acquiring the desired MS2 spectra, in comparison to 51 detected by LC-MS/MS. DI-MS/MSALL measurements merely took 5 min, which was dramatically superior to the LC-MS/MS assay. Noteworthily, different from fruitful multi-charged MS1 signals for LC-MS/MS, most quasi-molecular ions received lower charged states. DI-MS/MSALL also possessed advantages such as lower solvent consumption and facile instrumentation; however, more sample was consumed. In conclusion, DI-MS/MSALL is eligible to act as an alternative analytical tool for LC-MS/MS towards the peptide mapping of proteinic drugs, particularly when a heavy measurement workload.

Widely quasi-quantitative analysis enables temporal bile acids-targeted metabolomics in rat after oral administration of ursodeoxycholic acid.

Bile acid (BA) pool homeostasis can be disturbed when cholestasis, and ursodeoxycholic acid (UDCA) treatment is able to rectify the perturbed pool. Efforts were made here to propose a strategy enabling BAs-focused widely quantitative metabolomics and subsequently to lucubrate BA pool fluctuation trajectory in rats after dosing UDCA. A so-called universal metabolome standard (UMS) sample containing numerous natural BAs was constructed by involving various available BAs-enriched matrices. In-depth chemical characterization was conducted for UMS to capture as many BAs as possible. Diverse survey experiments were performed on Qtrap-MS to search BAs, and IT-TOF-MS was deployed to provide high-resolution m/z values for both precursor and fragment ion species. After structural annotation for 120 BAs, in total, online energy-resolved MS was subsequently programmed to pursue superior parameters for certain BAs, particularly BAs bearing two conjugated moieties. UMS was serially diluted to generate calibration sample set, and the regressive calibration curves, 120 ones in total, were responsible for converting each analyte response to quasi-content (1/dilution fold). The validated widely quasi-quantitative program was then applied to profile BA pool shift trajectories against time in UDCA- and vehicle-treated rats. Mild variations were observed for the quantitative pattern of BA pool from vehicle group, whereas UDCA could significantly shape BAs sub-metabolome. Significant increments occurred for the contents of not only the downstream BAs, but some upstream molecules in BA metabolic network. The shift levels of BAs were primarily governed by their distances away from UDCA. Fourteen differential BAs were involved for absolute quantitation to generate the concentration vs. time patterns, and dramatic upgradation occurred for most BAs, consolidating the variations transmitted from large-scale quasi-quantitative metabolomics. Above all, current study revealed the quasi-quantitative details of BA pool fluctuation initiated by UDCA-treatment, and more importantly, provided a promising approach for temporal BAs-targeted metabolomics.

Integrated strategy for widely targeted metabolome characterization of Peucedani Radix.

Herbal medicines (HMs) are widely recognized as extremely complicated matrices, resulting in a great challenge for the existing analytical approaches to characterize the widely targeted metabolome. The primary obstacles include high-level structural diversity, broad concentration range, large polarity span, insufficient authentic compounds and frequent occurrences of isomers, even enantiomers. Here, we aimed to propose an integrated strategy being able to circumvent the technical barriers, and a well-known HM namely Peucedani Radix was employed to illustrate and justify the applicability. Regarding qualitative analysis, the hydrophilic metabolites were detected with HILIC-predictive multiple-reaction monitoring mode, and structurally identified by matching predefined identities with authentic compounds or information archived in relevant databases. After RPLC-MS/MS measurement, full collision energy ramp-MS2 spectrum in combination with quantum structural calculation was applied to confirmatively identify those less polar components, mainly angular-type pyranocoumarins (APs). For quantitative analysis, achiral-chiral RPLC/HILIC was configured for chromatographic separations because the analytes spanned a large polarity range and involved many enantiomers. A quasi-content concept was employed for comprehensively relative quantitation through constructing a so-called universal metabolome standard (UMS) sample and building calibration curves by assaying serial diluted UMS solutions. Consequently, high-confidence structural annotation and relatively quantitative analysis were achieved for 103 compounds, in total. After multivariate statistical analysis, some APs, e.g., (3'S)-praeruptorin A, (3'S)-praeruptorin B, (3'S)-praeruptorin E, as well as several primary metabolites were screened out as the prominent contributors for inter-batch variations. Together, current study shows a promising strategy enabling widely targeted metabolomics of, but not limited to, HMs.

Online pressurized liquid extraction enables directly chemical analysis of herbal medicines: A mini review.

Extraction is responsible for transferring components from solid materials into solvent. Tedious extraction procedures are usually involved in liquid chromatography-based chemical analysis of herbal medicines (HMs), resulting in extensive consumptions of organic solvents, time, energy, and materials, as well as the significant chemical degradation risks for those labile compounds. Fortunately, an emerging online pressurized liquid extraction (OLE, also known as online liquid extraction) technique has been developed for the achievement of directly chemical analysis for solid matrices in recent years, and in a short period, this versatile technique has been widely applied for the chemical analysis of HMs. In the present mini-review, we aim to briefly summarize the principles, the instrumentation, along with the application progress of this robust and flexible extraction technique in the latest six years, and the emerging challenges and future prospects are discussed as well. Special attention is paid onto the hyphenation of the versatile OLE module with LC-MS instrument. The described information is expected to introduce a promising OLE approach and to provide the guidance for the achievement of directly chemical analysis of, but not limited to, HMs.