Intelligent chemical profiling of 73 edible flowers by liquid chromatography-high resolution mass spectrometry combined with HRMS database and their authentication based on large-scale fingerprints.

A commercial high-resolution MS database "TCM-PCDL" was innovatively introduced to automatically identify multi-components in 73 edible flowers rapidly and accurately by liquid chromatography-high resolution mass spectrometry, which can be time-consuming and labor-intensive in traditional manual method. The database encompasses over 2565 natural products with various energy levels. Unknown compounds can be identified through direct matching and scoring MS2 spectra with database. A total of 870 compounds were identified from 73 flowers, with polyphenols constituting up to 75%. Focusing on polyphenols, a high performance liquid chromatography (HPLC) method was developed to generate fingerprints from 510 batches, establishing an "HPLC database" that enabled accurate authentication using similarity scores and rankings. This method demonstrated an accuracy rate of 100% when applied to 30 unknown samples. For flowers prone to confusion, additional statistical analysis methods could be employed as aids in authentication. This study provides valuable insights for large-scale sample chemical profiling and authentication.

Comprehensive HRMS Screening and Risk Assessments of Aristolochic Acid Analogues in Asari Radix et Rhizoma and Related Commercial Health Products.

Aristolochic acid analogues (AAAs) are well-known toxins. We performed the first comprehensive screening on AAAs in Asari Radix et Rhizoma (underground part of Asarum heterotropoides Schmidt), the only Aristolochiaceae plant widely used in clinical practice. LC-HRMS revealed 70 trace AAAs using polygonal mass defect filtering and precursor ion list strategies, 38 of which were newly discovered in A. heterotropoides. UHPLC-QTrap-MS/MS was then utilized for quantitative/semiquantitative analysis of 26 abundant compounds. Seventeen AAAs were detected from 91 batches of A. heterotropoides and 20 AAAs from 166 consumable products. For 141 Asari-containing proprietary products, aristolactam I and aristolactam II-glucoside exhibited the widest distribution, present in 98% products. AA IVa was the most abundant, detected in 91%. Notably, 60% of the products contained AA I (0.03-0.79 ppm). The safety was assessed using linear extrapolation, permitted daily exposure, cumulative amount, and the margin of exposure. It is recommended that AA I content be limited to 3 ppm.

Integrated UPLC/Q-TOF-MS/MS Analysis and Network Pharmacology to Reveal the Neuroprotective Mechanisms and Potential Pharmacological Ingredients of Aurantii Fructus Immaturus and Aurantii Fructus.

Aurantii Fructus (AF) and Aurantii Fructus Immaturus (AFI) have been used for thousands of years as traditional Chinese medicine (TCM) with sedative effects. Modern studies have shown that Citrus plants also have protective effects on the nervous system. However, the effective substances and mechanisms of action in Citrus TCMs still remain unclear. In order to explore the pharmacodynamic profiles of identified substances and the action mechanism of these herbs, a comprehensive approach combining ultra-high-performance liquid chromatography with quadrupole time-of-flight mass spectrometry (UPLC/Q-TOF-MS/MS) analysis and network pharmacology was employed. Firstly, UNIFI 2.1.1 software was used to identify the chemical characteristics of AF and AFI. Secondly, the SwissTargetPrediction database was used to predict the targets of chemical components in AF and AFI. Targets for neuroprotection were also collected from GeneCards: The Human Gene Database (GeneCards-Human Genes|Gene Database|Gene Search). The networks between targets and compounds or diseases were then constructed using Cytoscape 3.9.1. Finally, the Annotation, Visualization and Integrated Discovery Database (DAVID) (DAVID Functional Annotation Bioinformatics Microarray Analysis) was used for GO and pathway enrichment analysis. The results showed that 50 of 188 compounds in AF and AFI may have neuroprotective biological activities. These activities are associated with the regulatory effects of related components on 146 important signaling pathways, derived from the KEGG (KEGG: Kyoto Encyclopedia of Genes and Genomes), such as neurodegeneration (hsa05022), the Alzheimer's disease pathway (hsa05010), the NF-kappa B signaling pathway (hsa04064), the hypoxia-inducible factor (HIF)-1 signaling pathway (hsa04066), apoptosis (hsa04210), the epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor resistance signaling pathway (hsa01521), and others, by targeting 108 proteins, including xanthine dehydrogenase (XDH), glutamate ionotropic receptor NMDA type subunit 2B (GRIN2B), and glucose-6-phosphate dehydrogenase (G6PD), among others. These targets are thought to be related to inflammation, neural function and cell growth.

Systematical targeted multicomponent characterization and comparison of Arnebiae Radix and its three confusing species by offline two-dimensional liquid chromatography/LTQ-Orbitrap mass spectrometry.

Arnebiae Radix, commonly known as "Zicao," can be easily confused with other compounding species, posing challenges for its clinical use. Here, we developed a comprehensive strategy to systematically characterize the diverse components across Arnebiae Radix and its three confusing species. First, an offline two-dimensional liquid chromatography (2D-LC) system integrating hydrophilic interaction chromatography (HILIC) and reverse phase (RP) separations was established, enabling effective separation and detection of more trace constituents. Second, a polygonal mass defect filtering (MDF) workflow was implemented to screen target ions and generate a precursor ion list (PIL) to guide multistage mass (MSn) data acquisition. Third, a three-step characterization strategy utilizing diagnostic ions and neutral losses was developed for rapid determination of molecular formulas, structure classes, and compound identification. This approach enabled systematic characterization of Arnebiae Radix and its three confusing species, with 437 components characterized including 112 shikonins, 22 shikonfurans, 144 phenolic acids, 131 glycosides, 18 flavonoids, and 10 other compounds. Additionally, 361, 230, 340, and 328 components were identified from RZC, YZC, DZC, and ZZC, respectively, with 142 common components and 30 characteristic components that may serve as potential markers for distinguishing the four species. In summary, this is the first comprehensive characterization and comparison of the phytochemical profiles of Arnebiae Radix and its three confusing species, advancing our understanding of this herbal medicine for quality control.

Species discrimination of multiple botanical origins of Fritillaria species based on infrared spectroscopy, thin layer chromatography-image analysis and untargeted metabolomics.

BACKGROUND: Fritillaria Bulbus (FB), a precious medicinal herb renowned for its heat-clearing, lung-moistening, cough-relieving and phlegm-eliminating effects. In pursuit of profits, unscrupulous merchants have engaged in the substitution or adulteration of valuable varieties with cheaper alternatives. It is, therefore, urgent to develop effective technical approaches to identify FBs from adulterants. METHODS: This paper employed infrared spectroscopy (IR), thin layer chromatography-image analysis (TLC-IA), and untargeted metabolomics techniques to discriminate ten species of FBs. RESULTS: Five species of FBs were successfully differentiated using mid-infrared spectroscopy. Furthermore, the power of TLC-IA technology allowed the differentiation of five species of FBs and two origins of FCBs (Fritillariae Cirrhosae Bulbus). Remarkably, through the application of untargeted metabolomics technique, the precise discrimination of five species of FBs, as well as three origins of FCBs were accomplished. Moreover, a comprehensive identification of 101 markers that reliably distinguished diverse FBs was achieved through the employment of untargeted metabolomics technique. CONCLUSION: The investigation presented powerful means of detection for assuring the quality control of Fritillaria herbs.

Characterization of natural peptides in Pheretima by integrating proteogenomics and label-free peptidomics.

Pheretima, also called "earthworms", is a well-known animal-derived traditional Chinese medicine that is extensively used in over 50 Chinese patent medicines (CPMs) in Chinese Pharmacopoeia (2020 edition). However, its zoological origin is unclear, both in the herbal market and CPMs. In this study, a strategy for integrating in-house annotated protein databases constructed from close evolutionary relationship-sourced RNA sequencing data from public archival resources and various sequencing algorithms (restricted search, open search, and de novo) was developed to characterize the phenotype of natural peptides of three major commercial species of Pheretima, including Pheretima aspergillum (PA), Pheretima vulgaris (PV), and Metaphire magna (MM). We identified 10,477 natural peptides in the PA, 7,451 in PV, and 5,896 in MM samples. Five specific signature peptides were screened and then validated using synthetic peptides; these demonstrated robust specificity for the authentication of PA, PV, and MM. Finally, all marker peptides were successfully applied to identify the zoological origins of Brain Heart capsules and Xiaohuoluo pills, revealing the inconsistent Pheretima species used in these CPMs. In conclusion, our integrated strategy could be used for the in-depth characterization of natural peptides of other animal-derived traditional Chinese medicines, especially non-model species with poorly annotated protein databases.

Characterization of the natural peptidome of four leeches by integrated proteogenomics and pseudotargeted peptidomics.

Animal-derived drugs are an indispensable part of folk medicine worldwide. However, their chemical constituents are poorly approached, which leads to the low level of the quality standard system of animal-derived drugs and further causes a chaotic market. Natural peptides are ubiquitous throughout the organism, especially in animal-derived drugs. Thus, in this study, we used multi-source leeches, including Hirudo nipponica (HN), Whitmania pigra (WP), Whitmania acranulata (WA), and Poecilobdella manillensis (PM), as a model. A strategy integrating proteogenomics and novel pseudotargeted peptidomics was developed to characterize the natural peptide phenotype and screen for signature peptides of four leech species. First, natural peptides were sequenced against an in-house annotated protein database of closely related species constructed from RNA-seq data from the Sequence Read Archive (SRA) website, which is an open-sourced public archive resource. Second, a novel pseudotargeted peptidomics integrating peptide ion pair extraction and retention time transfer was established to achieve high coverage and quantitative accuracy of the natural peptides and to screen for signature peptides for species authentication. In all, 2323 natural peptides were identified from four leech species whose databases were poorly annotated. The strategy was shown to significantly improve peptide identification. In addition, 36 of 167 differential peptides screened by pseudotargeted proteomics were identified, and about one-third of them came from the leucine-rich repeat domain (LRR) proteins, which are widely distributed in organisms. Furthermore, six signature peptides were screened with good specificity and stability, and four of them were validated by synthetic standards. Finally, a dynamic multiple reaction monitoring (dMRM) method based on these signature peptides was established and revealed that one-half of the commercial samples and all of the Tongxinluo capsules were derived from WP. All in all, the strategy developed in this study was effective for natural peptide characterization and signature peptide screening, which could also be applied to other animal-derived drugs, especially for modelless species that are less studied in protein database annotation.

Systematical characterization of gypenosides in Gynostemma pentaphyllum and the chemical composition variation of different origins.

Gynostemma pentaphyllum (Thunb.) Makino is an herbaceous plant of Cucurbitaceae family, which has been widely used as an herbal tea and traditional Chinese medicine. Since its saponins are similar to ginsenosides and have a wide range of activities, it has attracted wide interest. However, there are still a large number of unknown saponins that have not been isolated, especially some trace gypenosides. In the present study, a HILIC × RP offline two-dimensional liquid separation combined with a multimode data acquisition was developed for the systematical characterization of gypenosides. On top of the negative mode information, considering that saponins are prone to in-source fragmentations in positive ion mode, a precursor ion list data acquisition method was used for the targeted acquisition of multistage positive data. Reference herbal drug was taken as a golden sample to probe the chemical composition of G. pentaphyllum. The mixed sample of commercially available samples were also analyzed in parallel. Furthermore, the chemical compositions of commercially available samples from different sources were compared. In total, 1108 saponins were characterized, among which 588 were accurately characterized, with 574 identified in the reference herbal drug and 700 in the mixed commercially available samples. The commercially available samples showed great composition variation. These findings clarified the material basis and provided clues for quality control of G. pentaphyllum.

A Scientometric Study to a Critical Review on Promising Anticancer and Neuroprotective Compounds: Citrus Flavonoids.

Flavonoids derived from citrus plants are favored by phytomedicinal researchers due to their wide range of biological activities, and relevant studies have been sustained for 67 years (since the first paper published in 1955). In terms of a scientometric and critical review, the scientometrics of related papers, chemical structures, and pharmacological action of citrus flavonoids were comprehensively summarized. The modern pharmacological effects of citrus flavonoids are primarily focused on their anticancer activities (such as breast cancer, gastric cancer, lung cancer, and liver cancer), neuroprotective effects (such as anti-Alzheimer's disease, Parkinson's disease), and metabolic diseases. Furthermore, the therapeutic mechanism of cancers (including inducing apoptosis, inhibiting cell proliferation, and inhibiting cancer metastasis), neuroprotective effects (including antioxidant and anti-inflammatory), and metabolic diseases (such as non-alcoholic fatty liver disease, type 2 diabetes mellitus) were summarized and discussed. We anticipate that this review could provide an essential reference for anti-cancer and neuroprotective research of citrus flavonoids and provide researchers with a comprehensive understanding of citrus flavonoids.

The content and distribution of 18 phenolic compounds in 462 batches of edible flowers from 73 species commercially available in China.

Phenolic compounds are widely distributed in plant flowers. The present study systematically analyzed 18 phenolic compounds, represented by 4 monocaffeoylquinic acids, 4 dicaffeoylquinic acids, 5 flavones and 5 other phenolic acids, in 73 species (462 batches of samples) of edible flowers by a new established and validated HPLC-UV (high-performance liquid chromatography ultraviolet) (327/217 nm) method. Among all the species analyzed, 59 species were demonstrated to contain at least one or more quantifiable phenolic compounds, especially in families of Composite, Rosaceae and Caprifoliaceae. 3-Caffeoylquinic acid was found to be the most ubiquitous phenolic compound (in 193 batches of 73 species with the content between 0.061 and 65.10 mg/g), followed by rutin and isoquercitrin. While sinapic acid, 1-Caffeoylquinic acid and 1,3-dicaffeoylquinic acid (only in 5 batches of 1 specie with the content between 0.069 and 0.12 mg/g) were the least ones both in ubiquity and concentration. Additionally, the distribution and abundances of phenolic compounds were compared between these flowers, which would be valuable for auxiliary authentication or other usages. This research covered almost all edible and medicinal flowers in the Chinese market with 18 phenolic compounds therein quantified, which delivered a bird view of phenolic compounds in a broad perspective of edible flowers.

Comprehensive quality evaluation of Aconiti Lateralis Radix Praeparata based on pseudotargeted metabolomics and simultaneous determination of fifteen components, and development of new processed products of black slices with less toxicity.

Aconiti Lateralis Radix Praeparata is one of the most famous traditional Chinese medicines possessing a variety of pharmacological activities on top of the toxicities. Due to the heterogeneity and non-standardization of the processing procedures, the subtypes and contents of the differential compounds between different processed products still remained indistinct, causing great risk in their proper use. In order to achieve the comparison and quality evaluation of different processed products of Aconiti Lateralis Radix Praeparata and develop new processed products with less toxicity, a quantification and pseudotargeted metabolomics method was developed based on the dynamic MRM mode of triple quadrupole (QqQ) mass spectrometry, and multivariate statistical analysis methods were applied to compare different processed products. Method validation results indicated good specificity, linearity, repeatability, precision, stability and recovery of the established quantification method and good linearity, precision and stability of the pseudotargeted metabolomics method. Differential compounds of different processed products were screened out and further confirmed by the quantification results. At last, the processing procedures were optimized to obtain new processed products of "Heishunpian" (black slices) with less toxicity, in which the contents of the toxic diester-type diterpenoid alkaloids were reduced from 106.98 µg/g to 0.85-12.96 µg/g. This study provided a valuable reference for the establishment of comprehensive quality evaluation methods of herbal medicines and a scientific basis for the optimization of processing procedures of Aconiti Lateralis Radix Praeparata.

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 ß-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.

Advances in the chemical constituents, pharmacological properties and clinical applications of TCM formula Yupingfeng San.

Yupingfeng San (YPFS) is a famous and commonly used traditional Chinese medicine (TCM) formula for the treatment of chronic obstructive pulmonary disease, asthma, respiratory tract infections, and pneumonia in China. It is composed of three Chinese herbs, including Astragali Radix, Atractylodis Macrocephalae Rhizoma and Saposhnikoviae Radix. In this review, the relevant references on YPFS were searched in the Web of Science, PubMed, China National Knowledge Infrastructure (CNKI), and other databases. Literatures published from 2000 to 2022 were screened and summarized. The constituents in YPFS could be classified into nine groups according to their structures, including flavonoids, saponins, essential oils, coumarins, lactones, amino acids, organic acids, saccharides, chromones and others. The importance of chemical constituents in YPFS were demonstrated for specific pathological processes including immunoregulatory, anti-inflammatory, anti-tumor and pulmonary diseases. This article systematically reviewed the up-to-date information on its chemical compositions, pharmacology and safety, that could be used as essential data and reference for clinical applications of YPFS.

Integration of offline two-dimensional chromatography and mass defect filtering-based precursor ion list data acquisition for targeted characterization of diterpenoid alkaloids in the lateral roots of Aconitum carmichaelii.

The hyphenated technique of offline two-dimensional (2D) chromatography with high resolution mass spectrometry (MS) was an efficient tool for separation and characterization of components in complex systems such as herbal medicines, especially those co-eluting components or isomers. In this study, we constructed the ultra-performance convergence chromatography (UPC2) × reversed phase (RP) chromatographic separation system and developed a mass defect filtering (MDF)-based precursor ion list (PIL) acquisition method to improve the selectivity and sensitivity of this technique, and the systematic characterization of diterpenoid alkaloids in the lateral roots of Aconitum carmichaelii (namely "Fuzi" in Chinese) was used as an example. The constructed offline 2D separation system showed a good orthogonality of 0.77. Besides, the in-house databases for known and predicted C19- and C20-diterpenoid alkaloids were established by molecular design in Compound Discoverer software for MS data matching and filtering, and two MDF windows were further constructed to screen out more potential diterpenoid alkaloids with novel structures and to obtain the PIL (mass range: even values between 298 and 1020 Da, parent mass width: ±100 mDa) for data acquisition by calculating the m/z values of potential ions using mass range and corresponding mass defect in the MDF windows. In addition, an integrative structure interpretation strategy was developed by integrating elemental composition analysis, ring double bond analysis, neutral loss filtering, diagnostic ion filtering and database matching, etc. As a result, a total of 659 components in the lateral roots of A. carmichaelii were exposed and characterized, including 526 potential new compounds. This strategy showed significant advantages in improving the coverage and selectivity of screening, and could also be applied in systematic characterization of components in other herbal medicines.

Application of Analytical Technologies in the Discrimination and Authentication of Herbs from Fritillaria: A Review.

Medicinal plants of Fritillaria are widely distributed in numerous countries around the world and possess excellent antitussive and expectorant effects. In particular, Fritillariae Bulbus (FB) as a precious traditional medicine has thousands of years of medical history in China. Herbs of Fritillaria have a high market value and demand while limited by harsh growing circumstances and scarce wild resources. As a consequence, fraudulent behaviors are regularly engaged by the unscrupulous merchants in an attempt to reap greater profits. It is of an urgent need to evaluate the quality of Fritillaria herbs and their products using various analytical instruments and techniques. This review has scrutinized approximately 160 articles from 1995 to 2022 published on the investigation of Fritillaria herbs and related herbal products. The botanical classification of genus Fritillaria, types of counterfeits, technologies applied for differentiating Fritillaria species were comprehensively summarized and discussed in the current review. Molecular and chromatographic identification were the dominant technologies in the authentication of Fritillaria herbs. Additionally, we brought some potential and promising technologies and analytical strategies into attention, which are worthy attempting in the future researches. This review could conduce to excellent reference value for further investigations of the authenticity assessment of Fritillaria species.

Electrostimulation of fibroblast proliferation by an electrospun poly (lactide-co-glycolide)/polydopamine/chitosan membrane in a humid environment.

Exogenous electrical stimulation (ES) facilitates skin wound healing and accelerates cell proliferation. Scaffolds fabricated with electrically-conductive materials combined with ES further promote cellular activity. Here, an electrospun membrane made of poly (lactide-co-glycolide) (PLGA) coated with chitosan (CS) via polydopamine (PDA) serving as a linker was developed and evaluated in vitro for the proliferation and migration of fibroblast cells involved in skin wound repair. PLGA/PDA/CS exhibited multiple optimal characteristics for cell proliferation and dressing materials including good mechanical properties, low cytotoxicity, a super-hydrophilic surface, and an excellent swelling ratio suitable for the absorption of wound exudates. Because of ionic charges, wet PLGA/PDA/CS had an electrical conductivity of 2.85 × 10-3 S/cm, which was comparable to the highest electrical conductivities observed with natural skin. Upon intermittent ES of 100 mV, PLGA/PDA/CS increased fibroblast proliferation 2 and 1.3 times compared to PLGA and PLGA/PDA, respectively. These results demonstrate the potential of PLGA/PDA/CS as a biodegradable polymeric surface for the ES of cells involved in skin wound healing. It also shows that polymers with low electrical conductivity in dry conditions can become suitable for the ES of humid wounds where ionic conductivity is occurring.

Novel triterpenoids from Alisma plantago-aquatica with influence on LDL uptake in HepG2 cells by inhibiting PCSK9.

BACKGROUND: Proprotein convertase subtilisin/kexin type 9 (PCSK9) has been regarded as an effective and exciting target in the treatment of atherosclerotic cardiovascular disease since 2003. Only two monoclonal antibodies have been approved in the market which, however, were also criticized for their high cost to $9000 per dose and delivery route. Exploration of natural new effective and cheaper small molecule alternatives with effective PCSK9 inhibition is feasible and desired. PURPOSE: The aim of the study was to explore natural small molecules with anti-hyperlipidemia activity through PCSK9 from Alisma plantago-aquatica. METHOD: A targeted isolation of triterpenoids from A. plantago-aquatica by LC-Orbitrap-QDa was conducted. The isolates were evaluated for their DiI-LDL uptake promoting activity with fluorescence intensity assayed in High-content Imaging System and PCSK9 inhibitory activity by Human PCSK9 Kit or western blot. The LDL uptake and PCSK9 level of target component in different concentrations and their mRNA level were further verified by corresponding kit, qPCR and western blot. RESULTS: Six novel triterpenoids, including three unusual nor-triterpenoids (1-3) and three protostane-type triterpenoids (4-6), along with thirty-four known ones, were isolated from A. plantago-aquatica. Compound 2 had the lowest number of carbon atoms than previous reported nor-PTs in this plant. The 17 triterpenoids showed relatively remarkable activities in promoting LDL uptake with relevant structure-activity relationships. And 6 triterpenoids may improve LDL uptake in HepG2 cells by inhibiting PCSK9, especially for alisol G (28) with PCSK9 inhibition reaching to 55.6%, which demonstrated to increase LDLR mRNA or protein, and simultaneously reduce PCSK9 mRNA or protein significantly. CONCLUSION: The protostane triterpenoids may serve as a new source for PCSK9 inhibitors.

Deep chemical identification of phytoecdysteroids in Achyranthes bidentata Blume by UHPLC coupled with linear ion trap-Orbitrap mass spectrometry and targeted isolation.

Achyranthes bidentata Blume is widely used as a traditional Chinese medicine with the effects of nourishing the liver and kidneys and strengthening muscles and bones. In this work, a rapid and simple strategy was developed for characterizing phytoecdysteroids by ultra-high-performance liquid chromatography coupled with liner ion trap-Orbitrap mass spectrometry using electrospray ionization in the negative mode. As a result, 47 phytoecdysteroids were unambiguously or tentatively characterized. Among them, seven known compounds were identified according to the reference standards along with molecular formula, retention time and fragmentation patterns, while others were mostly potential new compounds. Through targeted isolation, the structures of three new compounds were determined by NMR spectra, which were consistent with LC-MS characterization. The present study provides an efficient method to deeply characterize phytoecdysteroids.

Systematic screening and structural characterization of dipeptides using offline 2D LC-LTQ-Orbitrap MS: A case study of Cordyceps sinensis.

Cordyceps sinensis (C. sinensis) is a widely used and highly valuable traditional Chinese medicine. Several dipeptides have been detected in C. sinensis, but current scientific knowledge of its chemical makeup remains limited. In this study, an improved approach that integrates offline two-dimensional liquid chromatography (2D LC) separation, precursor ion list, library screening, and diagnostic ion filtering was established to systematically screen and characterize dipeptides in C. sinensis. Offline 2D LC integrating hydrophilic interaction LC and reverse phase separations was established to eliminate interference and identify the target dipeptides. A library containing the potential 400 dipeptides was created, and a precursor ion list with all theoretical precursor ions was adopted to trigger the MS/MS scan with high sensitivity. To identify dipeptides, the type and connection sequence of amino acids were determined according to the product ions. Ile and Leu residues were differentiated for the first time according to the characteristic ion at m/z 69.07. Ultimately, 170 dipeptides were identified or tentatively characterized from C. sinensis, and most are reported for the first time in this species herein. In addition, the identified dipeptides were also applied for discrimination among the three Cordyceps species, and 11 markers were identified. The obtained results provide a deeper understanding of the chemical basis of C. sinensis.

Systematical characterization and comparison of saponins in Achyranthes bidentata Blume and its three analogous species.

INTRODUCTION: Achyranthes bidentata Blume (AB) has been used for a long time and is recorded in the Chinese Pharmacopoeia 2020 edition. It is commonly confused with Achyranthes aspera Linn (AA), Cyathula officinalis Kuan (CO) and Cyathula capitata (Wall.) Moq. (CC), belonging to the Achyranthes and Cyathula genera of the Amaranthaceae family. It is of great significance to recognize and distinguish chemical components of AB, AA, CO and CC. OBJECTIVE: The purpose of this study was to develop an analytical method for in-depth characterization and comparison of saponins in AB, AA, CO and CC. METHODS: The extracts of AB, AA, CO and CC were analyzed by an RP × RP (C18 × Phenyl-Hexyl) 2D LC system, eluted by acidic × ion pair mobile phases and detected by high resolution mass spectrometry. Fragmentation patterns of saponins were elucidated and proposed according to reference compounds or literature reports. RESULTS: As a result, 839 saponins consisting of 81, 415, 99 and 392 components corresponding to AB, AA, CO and CC, respectively, were characterized, including 594 potentially new saponins. Meanwhile, 29 kinds of aglycones were elucidated, among which 25 were new ones. Besides, 14, 91, 37 and 174 characteristic potential quality markers with MS intensities exceeding 10,000 were found in AB, AA, CO and CC, respectively. CONCLUSION: This comprehensive study not only expands our knowledge of the types of saponins in Achyranthes and Cyathula, but also reveals the differences among four kinds of analogous herbs (AB, AA, CO and CC), which facilitates the quality control of these herbal medicines in the future.