Homolog-focused profiling of ginsenosides based on the integration of step-wise formate anion-to-deprotonated ion transition screening and scheduled multiple reaction monitoring

Enhanced profiling and quantification of ginsenosides from mountain-cultivated ginseng and comparison with garden-cultivated ginseng

Panax ginseng can be generally divided into mountain-cultivated ginseng (MCG) and garden-cultivated ginseng (GCG). The market price of MCG is significantly higher than that of GCG. However, the chemical compositions of MCG and the differences from GCG remained unclear. In this study, an integrated strategy combing an offline two-dimensional liquid chromatography separation, LTQ-orbitrap dual mode acquisition, and Q-trap full quantification/quasi-quantification was proposed to explore and compare the chemical compositions of MCG. Consequently, 559 ginsenosides were characterized, among which 437 ginsenosides were in-depth characterized with α-chain and β-chain annotated. Subsequently, enhanced quantification of 213 ginsenosides was conducted in 57 batches of MCG and GCG. Ginsenosides were found more abundant in MCG than GCG. In addition, 25-year-old MCG could be distinctly differentiated from 15/20-year-old MCG. This strategy facilitated the enhanced profiling and comparison of ginsenosides, improved the quality control tactics of MCG and provided a reference approach for other ginseng related products.

Comparison of two methods for ginsenosides quantitation

The present study provides a comparison of two liquid chromatography-tandem mass spectrometry methods for ginsenosides analysis. The two methods have the same liquid chromatography separation procedure, and both use tandem mass spectrometry detection. However, one method uses multiple reaction monitoring transitions commonly recommended in the literature starting with [M + Na]⁺ as the molecular ions and with detection of specific fragment ions from the molecules M, while the other is an original method using [M + Cs]⁺ as molecular ions and Cs⁺ as fragment ion. The method using [M + Cs]⁺ as molecular ion has a very high sensitivity allowing the measurement of concentrations in the injecting solutions as low as 4 ng/ml with peaks at this concentration showing signal to noise ratio of 20 or higher. The procedures were utilized for the measurement of eight ginsenosides (Rb1, Rb2, Rc, Rd, Re, Rf (S), Rg1, and Rg2), although the method using [M + Cs]⁺ has the potential for measuring other ginsenosides. As an application, the ginsenosides were measured in several types of ginseng root, several dietary supplements containing ginseng extracts, four energy drinks, and a sample of ashwagandha.

Advances and challenges in ginseng research from 2011 to 2020: the phytochemistry, quality control, metabolism, and biosynthesis

Covering: 2011 to the end of 2020Panax species (Araliaceae), particularly P. ginseng, P. quinquefolius, and P. notoginseng, have a long history of medicinal use because of their remarkable tonifying effects, and currently serve as crucial sources for various healthcare products, functional foods, and cosmetics, aside from their vast clinical preparations. The huge market demand on a global scale prompts the continuous prosperity in ginseng research concerning the discovery of new compounds, precise quality control, ADME (absorption/disposition/metabolism/excretion), and biosynthesis pathways. Benefitting from the ongoing rapid development of analytical technologies, e.g. multi-dimensional chromatography (MDC), personalized mass spectrometry (MS) scan strategies, and multi-omics, highly recognized progress has been made in driving ginseng analysis towards "systematicness, integrity, personalization, and intelligentization". Herein, we review the advances in the phytochemistry, quality control, metabolism, and biosynthesis pathway of ginseng over the past decade (2011-2020), with 410 citations. Emphasis is placed on the introduction of new compounds isolated (saponins and polysaccharides), and the emerging novel analytical technologies and analytical strategies that favor ginseng's authentic use and global consumption. Perspectives on the challenges and future trends in ginseng analysis are also presented.

Identification and characterization of quinoline alkaloids from the root bark of Dictamnus dasycarpus and their metabolites in rat plasma, urine and feces by UPLC/Qtrap-MS and UPLC/Q-TOF-MS

Quinoline alkaloids are the main bioactive and potentially toxic constituents in the root bark of Dictamnus dasycarpus Turcz. (BXP), a widely used traditional Chinese medicine for the treatment of skin inflammation, eczema and rubella. However, the comprehensive analysis of the chemical components and metabolites of quinoline alkaloids remain unclear. In this study, an integrated strategy by combining UPLC/Q-TOF-MS and UPLC/Qtrap-MS was established to comprehensively profile the quinoline alkaloids from BXP and their metabolites in rat plasma, urine and feces. Q-TOF-MS (MS^E mode), Qtrap-MS (EMS, MIM, pMRM and NL mode) were performed for acquiring more precursor ions and clearer precursor product ions. A step-by-step manner based on the diagnostic fragment ions (DFIs), in-house database, ClogP value and dipole moment (μ) was proposed to overcome the complexities due to the similar fragmentation behaviors of the quinoline alkaloids. As a result, a total of 73 quinoline alkaloids were unambiguously or tentatively identified. Among them, 4 furoquinolines, 10 dihydrofuroquinolines, 2 pyranoquinolinones, 4 dihydropyranoquinolinones and 9 quinol-2-ones were characterized in BXP for the first time. Moreover, a total of 98 BXP-related constituents (including 57 prototypes and 41 metabolites) were detected in rat plasma, urine and feces. The metabolic pathways included phase I reactions (O-demethylation, hydroxylation and 2,3-olefinic epoxidation) and phase II reactions (conjugation with glucuronide, sulfate and N-acetylcysteine). In conclusion, the integrated strategy with the proposed stepwise manner is suitable for rapid identifying and characterizing more extensive quinoline alkaloids of BXP in vitro and in vivo. Moreover, the results will be helpful for revealing the pharmacological effective substances or toxic substances of BXP and provide a solid basis for further research.

Insight into chemical basis of traditional Chinese medicine based on the state-of-the-art techniques of liquid chromatography-mass spectrometry

Traditional Chinese medicine (TCM) has been an indispensable source of drugs for curing various human diseases. However, the inherent chemical diversity and complexity of TCM restricted the safety and efficacy of its usage. Over the past few decades, the combination of liquid chromatography with mass spectrometry has contributed greatly to the TCM qualitative analysis. And novel approaches have been continuously introduced to improve the analytical performance, including both the data acquisition methods to generate a large and informative dataset, and the data post-processing tools to extract the structure-related MS information. Furthermore, the fast-developing computer techniques and big data analytics have markedly enriched the data processing tools, bringing benefits of high efficiency and accuracy. To provide an up-to-date review of the latest techniques on the TCM qualitative analysis, multiple data-independent acquisition methods and data-dependent acquisition methods (precursor ion list, dynamic exclusion, mass tag, precursor ion scan, neutral loss scan, and multiple reaction monitoring) and post-processing techniques (mass defect filtering, diagnostic ion filtering, neutral loss filtering, mass spectral trees similarity filter, molecular networking, statistical analysis, database matching, etc.) were summarized and categorized. Applications of each technique and integrated analytical strategies were highlighted, discussion and future perspectives were proposed as well.

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

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.

Application of Identification and Evaluation Techniques for Ethnobotanical Medicinal Plant of Genus Panax: A Review

Genus Panax, as worldwide medicinal plants, has a medical history for thousands of years. Most of the entire genus are traditional ethnobotanical medicine in China, Myanmar, Thailand, Vietnam and Laos, which have given rise to international attention and use. This paper reviewed more than 210 articles and related books on the research of Panax medicinal plants and their Chinese patent medicines published in the last 30 years. The purpose was to review and summarize the species classification, geographical distribution, and ethnic minorities medicinal records of the genus Panax, and further to review the analytical tools and data analysis methods for the authentication and quality assessment of Panax medicinal materials and Chinese patent medicines. Five main technologies applied in the identification and evaluation of Panax have been introduced and summarized. Chromatography was the most widely used one. Further research and development of molecular identification technology had the potential to become a mainstream identification technology. In addition, some novel, controversial, and worthy methods including electronic noses, electronic eyes, and DNA barcoding were also introduced. At the same time, more than 80% of the researches were carried out by a combination of chemometric pattern-recognition technologies and multi-analysis technologies. All the technologies and methods applied can provide strong support and guarantee for the identification and evaluation of genus Panax, and also conduce to excellent reference value for the development and in-depth research of new technologies in Panax.

An integrated multiple reaction monitoring strategy based on predicted precursor ions and characteristic product ions for global profiling Rubiaceae-type cyclopeptides in three Rubiaspecies

Complexity and diversity of natural compounds make it a challenge for globally profiling constituents in multiple species plants, especially for minor new compounds. Rubiaceae-type cyclopeptides (RAs) are one kind of active constituents and characteristic components in Rubia plants, particularly Rubia cordifolia (RC), which is one kind of traditional Chinese medicines. In this study, a new multiple reaction monitoring strategy (PPCP-MRM) based on predicted precursor ions and characteristic product ions was developed to globally profile RAs in RC and its two main adulterants, including Rubia alata (also named Jinjiancao in Chinese) (RAJ) and Rubia podantha (RP). Moreover, characteristic components of these species have been found by targeted relative quantitative analysis of RAs by LC-MS. In total, 39 RAs have been structurally annotated based on fragment ions in MS² data, including 19 new compounds. In addition, 7 RAs as the chemical markers were found to distinguish these three Rubia species. The results indicated that this PPCP-MRM integrated strategy is a powerful tool for comprehensive analysis of RAs and screening chemical markers for Rubia species discrimination, which would be useful for distinguishing Rubia adulterants. Furthermore, this developed strategy could also be a useful tool for analysis of other cyclopeptides.

Phytochemical analysis of Panax species: a review

Panax species have gained numerous attentions because of their various biological effects on cardiovascular, kidney, reproductive diseases known for a long time. Recently, advanced analytical methods including thin layer chromatography, high-performance thin layer chromatography, gas chromatography, high-performance liquid chromatography, ultra-high performance liquid chromatography with tandem ultraviolet, diode array detector, evaporative light scattering detector, and mass detector, two-dimensional high-performance liquid chromatography, high speed counter-current chromatography, high speed centrifugal partition chromatography, micellar electrokinetic chromatography, high-performance anion-exchange chromatography, ambient ionization mass spectrometry, molecularly imprinted polymer, enzyme immunoassay, ¹H-NMR, and infrared spectroscopy have been used to identify and evaluate chemical constituents in Panax species. Moreover, Soxhlet extraction, heat reflux extraction, ultrasonic extraction, solid phase extraction, microwave-assisted extraction, pressurized liquid extraction, enzyme-assisted extraction, acceleration solvent extraction, matrix solid phase dispersion extraction, and pulsed electric field are discussed. In this review, a total of 219 articles published from 1980 to 2018 are investigated. Panax species including P. notoginseng, P. quinquefolius, sand P. ginseng in the raw and processed forms from different parts, geographical origins, and growing times are studied. Furthermore, the potential biomarkers are screened through the previous articles. It is expected that the review can provide a fundamental for further studies.

A novel neutral loss/product ion scan-incorporated integral approach for the untargeted characterization and comparison of the carboxyl-free ginsenosides from Panax ginseng, Panax quinquefolius, and Panax notoginseng

Differentiated composition in precursor ions for different subclasses of ginsenosides in the negative electrospray-ionization mode has been reported, which lays a foundation for the sorted and untargeted identification of ginsenosides. Carboxyl-free ginsenosides simultaneously from Panax ginseng, P. quinquefolius, and P. notoginseng, were comprehensively characterized and statistically compared. A neutral loss/product ion scan (NL-PIS) incorporated untargeted profiling approach, coupled to ultra-high performance liquid chromatography, was developed on a linear ion-trap/Orbitrap mass spectrometer for characterizing carboxyl-free ginsenosides. It incorporated in-source fragmentation (ISF) full scan-MS¹, mass tag-MS², and product ion scan-MS³. Sixty batches of ginseng samples were analyzed by metabolomics workflows for the discovery of ginsenoside markers. Using formic acid (FA) as the additive, carboxyl-free ginsenosides (protopanaxadiol-type, protopanaxatriol-type, and octillol-type) gave predominant FA-adducts, while rich deprotonated molecules were observed for carboxyl-containing ginsenosides (oleanolic acid-type and malonylated) when source-induced dissociation (SID) was set at 0 V. Based on the NL transition [M+FA‒H]^- > [M-H]^- and the characteristic sapogenin product ions, a NL-PIS approach was established. It took advantage of the efficient full-information acquisition of ISF-MS¹ (SID: 50 V), the high specificity of mass tag (NL: 46.0055 Da)-induced MS² fragmentation, and the substructure fragmentation of product ion scan-MS³. We could characterize 216 carboxyl-free ginsenosides, and 21 thereof were potentially diagnostic for the species differentiation. Conclusively, sorted and untargeted characterization of the carboxyl-free ginsenosides was achieved by the established NL-PIS approach. In contrast to the conventional NL or PIS-based survey scan strategies, the high-accuracy MSⁿ data obtained can enable more reliable identification of ginsenosides.

An enhanced strategy integrating offline two-dimensional separation and step-wise precursor ion list-based raster-mass defect filter: Characterization of indole alkaloids in five botanical origins of Uncariae Ramulus Cum Unicis as an exemplary application

Comprehensive chemical profiling is of great significance for understanding the therapeutic material basis and quality control of herbal medicines, which is challenging due to its inherent chemical diversity and complexity, as well as wide concentration range. In this study, we introduced an enhanced strategy integrating offline two-dimensional (2D) separation and the step-wise precursor ion list-based raster-mass defect filter (step-wise PIL-based raster-MDF) scan by tandem LTQ-Orbitrap mass spectrometer. A comprehensive analysis of indole alkaloids in five botanical origins of Uncariae Ramulus Cum Unicis (Gou-Teng) was used as an exemplary application. A positively charged reversed phase (PR) × conventional RP LC system in different pH conditions was constructed with the orthogonality of 74%. A theoretical step-wise PIL among 310-950 Da with the step-size of 2 Da was developed to selectively trigger fragmentations and extend the coverage of potential indole alkaloids. Simultaneously, by defining parent mass width (PMW) of the step-wise PIL to ±55 mDa, a raster-MDF screening was achieved in the acquisition process. Additionally, subtype classification and structural elucidation were facilitated by a four-step interpretation strategy. As a result, a total of 1227 indole alkaloids were efficiently exposed and characterized from five botanical origins of Gou-Teng, which showed high chemical diversity. A systematic comparison among five species was first performed and only 66 indole alkaloids were common. For method validation, three new alkaloid N-oxides were isolated and unambiguously identified by NMR. The present study provides a novel data-dependent acquisition method with improved target coverage and high selectivity. The integrated strategy is practical to efficiently expose and comprehensively characterize complex components in herbal medicines.

Untargeted metabolite analysis-based UHPLC-Q-TOF-MS reveals significant enrichment of p-hydroxybenzyl dimers of citric acids in fresh beige-scape Gastrodia elata (Wutianma)

In order to comprehensively elucidate the chemical biosynthesis process of the beige-scape Gastrodia elata Blume (Wutianma) as a traditional herbal medicines, the untargeted analysis-based UHPLC-PDA-ESI-Q-TOF-MS reveals the metabolites ranging from the skeletons to novel dimers of citric acids in fresh and dried immature/mature stem tubers. Interestingly, two novel types of dimers for citric acids with the anhydride groups at sn-1 and/or sn-5 were discovered in fresh samples. Moreover, the classical mono- versus novel di-mers, and the aglycons versus the glycosides could be easily discriminated by signature fragmentation patterns and some novel adduct ions. The heat map of contents demonstrated more p-hydroxybenzyl metabolites than gastroxyl ones were determined in fresh Wutianma revealing a significant specificity with the lack of the sufficient gastrodin and gastroxyl products in biosynthetic pathway.

An enhanced targeted identification strategy for the selective identification of flavonoid O-glycosides from Carthamus tinctorius by integrating offline two-dimensional liquid chromatography/linear ion-trap-Orbitrap mass spectrometry, high-resolution diagnostic product ions/neutral loss filtering and liquid chromatography-solid phase extraction-nuclear magnetic resonance

Targeted identification of potentially bioactive molecules from herbal medicines is often stymied by the insufficient chromatographic separation, ubiquitous matrix interference, and pervasive isomerism. An enhanced targeted identification strategy is presented and validated by the selective identification of flavonoid O-glycosides (FOGs) from Carthamus tinctorius. It consists of four steps: (i) enhanced separation and detection by offline two-dimensional liquid chromatography/LTQ-Orbitrap MS (offline 2D-LC/LTQ-Orbitrap MS) using collision-induced dissociation (CID) and high-energy C-trap dissociation (HCD); (ii) improved identification of the major aglycones by acid hydrolysis and LC-SPE-NMR; (iii) simplified spectral elucidation by high-resolution diagnostic product ions/neutral loss filtering; and (iv) more convincing structural identification by matching an in-house library. An offline 2D-LC system configuring an Acchrom XAmide column and a BEH Shield RP-18 UPLC^® column enabled much better separation of the easily co-eluting components. Combined use of CID and HCD could produce complementary fragmentation information. The intensity ratios of the aglycone ion species ([Y₀-H]^-/Y₀^- and [Y₀-2H]^-/Y₀^-) in the HCD-MS² spectra were found diagnostic for discriminating the aglycone subtypes and characterizing the glycosylation patterns. Five aglycone structures (kaempferol, 6-hydroxykaempferol, 6-methoxykaempferol, carthamidin, and isocarthamidin) were identified based on the ¹H-NMR data recorded by LC-SPE-NMR. Of the 107 characterized flavonoids, 80 FOGs were first reported from C. tinctorius. Unknown aglycones, pentose, and novel acyl substituents were discovered. A new compound thereof was isolated and fully identified, which could partially validate the MS-oriented identification. This integral strategy can improve the potency, efficiency, and accuracy in the detection of new compounds from medicinal herbs and other natural sources.

An Integrated Strategy for Global Qualitative and Quantitative Profiling of Traditional Chinese Medicine Formulas: Baoyuan Decoction as a Case

Clarification of the chemical composition of traditional Chinese medicine formulas (TCMFs) is a challenge due to the variety of structures and the complexity of plant matrices. Herein, an integrated strategy was developed by hyphenating ultra-performance liquid chromatography (UPLC), quadrupole time-of-flight (Q-TOF), hybrid triple quadrupole-linear ion trap mass spectrometry (Qtrap-MS), and the novel post-acquisition data processing software UNIFI to achieve automatic, rapid, accurate, and comprehensive qualitative and quantitative analysis of the chemical components in TCMFs. As a proof-of-concept, the chemical profiling of Baoyuan decoction (BYD), which is an ancient TCMF that is clinically used for the treatment of coronary heart disease that consists of Ginseng Radix et Rhizoma, Astragali Radix, Glycyrrhizae Radix et Rhizoma Praeparata Cum Melle, and Cinnamomi Cortex, was performed. As many as 236 compounds were plausibly or unambiguously identified, and 175 compounds were quantified or relatively quantified by the scheduled multiple reaction monitoring (sMRM) method. The findings demonstrate that the strategy integrating the rapidity of UNIFI software, the efficiency of UPLC, the accuracy of Q-TOF-MS, and the sensitivity and quantitation ability of Qtrap-MS provides a method for the efficient and comprehensive chemome characterization and quality control of complex TCMFs.

MRM-based strategy for the homolog-focused detection of minor ginsenosides from notoginseng total saponins by ultra-performance liquid chromatography coupled with hybrid triple quadrupole-linear ion trap mass spectrometry

A validated MRM-based strategy was established for targeted detection of minor ginsenosides from NGTS by using a LC-Q-Trap/MS.

Potential of hyphenated ultra-high performance liquid chromatography-scheduled multiple reaction monitoring algorithm for large-scale quantitative analysis of traditional Chinese medicines

The combination of a core–shell ADME column with a sMRM algorithm offers the potential for large-scale quantitative analysis of the components in TCMs by providing not only high quality quantitative signals but also reliable MS² spectra.