Global metabolite profiling and diagnostic ion filtering strategy by LC-QTOF MS for rapid identification of raw and processed pieces of Rheum palmatum L

Comprehensive identification strategy for rapid profiling of chemical constituents using ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry with Rhubarb as an example

In this study, the collision induced dissociation tandem mass spectrometry (CID-MS/MS) fragmentation pathway of chemical components in rhubarb was wholly explored using 34 standards by UHPLC-QTOF-MS/MS in negative ion mode. In consequently, the diagnostic product ions for speedy screening and categorization of chemical components in rhubarb were ascertained based on their MS/MS splitting decomposition patterns and intensity analysis. According to these findings, a fresh two-step data mining strategy had set up. The initial key step involves the use of characteristic product ions and neutral loss to screen for different types of substituents and basic skeletons of compounds. The subsequent key step is to screen and classify different types of compounds based on their characteristic product ions. This method can be utilized for rapid research, classification, and identification of compounds in rhubarb. A total of 356 compounds were rapidly identified or tentatively characterized in three rhubarb species extracts, including 150 acylglucoside, 125 anthraquinone, 65 flavanols and 15 other compounds. This study manifests that the analytical strategy is feasible for the analysis of complex natural products in rhubarb.

The phytochemistry and pharmacology of three Rheum species: A comprehensive review with future perspectives

BACKGROUND

Rheum palmatum, R. tanguticum, and R. officinale, integral species of the genus Rheum, are widely used across global temperate and subtropical regions. These species are incorporated in functional foods, medicines, and cosmetics, recognized for their substantial bioactive components.

PURPOSE

This review aims to synthesize developments from 2014 to 2023 concerning the botanical characteristics, ethnopharmacology, nutritional values, chemical compositions, pharmacological activities, mechanisms of action, and toxicity of these species.

METHODS

Data on the three Rheum species were gathered from a comprehensive review of peer-reviewed articles, patents, and clinical trials accessed through PubMed, Google Scholar, Web of Science, and CNKI.

RESULTS

The aerial parts are nutritionally rich, providing essential amino acids, fatty acids, and minerals, suitable for use as health foods or supplements. Studies have identified 143 chemical compounds, including anthraquinones, anthrones, flavonoids, and chromones, which contribute to their broad pharmacological properties such as laxative, anti-diarrheal, neuroprotective, hepatoprotective, cardiovascular, antidiabetic, antitumor, anti-inflammatory, antiviral, and antibacterial effects. Notably, the materials science approach has enhanced understanding of their medicinal capabilities through the evaluation of bioactive compounds in different therapeutic contexts.

CONCLUSION

As medicinal and economically significant herb species, Rheum species provide both edible aerial parts and medicinal underground components that offer substantial health benefits. These characteristics present new opportunities for developing nutritional ingredients and therapeutic products, bolstering the food and pharmaceutical industries.

The water extract of Rheum palmatum has antioxidative properties and inhibits ROS production in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Rheum palmatum (RP) is a widely used traditional herb, which possesses antioxidant properties, inhibits ROS production and reduces fever.

AIM OF THE STUDY

The aim of this study was to examine the antioxidative properties of the water extract of RP on oxidative-stressed mice.

MATERIALS & METHODS

Forty mice were administered with DL-homocysteine (DL-Hcy) to induce oxidative stress and were divided into four groups: 1) CK: NaCl and water; 2) DL-Hcy: DL-Hcy and water; 3) DL-Hcy+50RP: DL-Hcy with 50 mg kg-1 body weight (BW) d-1 RP; and 4) DL-Hcy+150RP: DL-Hcy with 150 mg kg-1 BW d-1 RP. Rhein (0.3 mg g-1 dry matter) was the main active ingredient in RP.

RESULTS

When compared with Dl-Hcy mice, the mice with supplementary RP mitigated oxidative stress by reducing the liver concentrations of superoxide dismutase (SOD) by 27% and glutathione peroxidase (GSH-Px) by 32%, and the reactive oxygen species (ROS) in the kidney and spleen. These responses were more pronounced in DL-Hcy+150RP than DL-Hcy+50RP mice. RP also exhibited therapeutic effects on liver steatosis, chronic kidney nephritis and intestinal villus width shortening caused by oxidative stress, and concomitantly decreased the serum glucose concentration (RP vs. DL-HCY, 2.3 vs. 4.1 mmol L-1).

CONCLUSION

It was concluded that RP possesses antioxidant and therapeutic properties that can mitigate lesions on organs and prevent diabetes in oxidative-stressed mice. This study highlights the potential of RP as a medicinal supplement for animals in the future.

Chemical Profiling of Shen-Wu-Yi-Shen Tablets Using UPLC-Q-TOF-MS/MS and Its Quality Evaluation Based on UPLC-DAD Combined with Multivariate Statistical Analysis

Shen-Wu-Yi-Shen tablets (SWYST) is a traditional Chinese medicine prescription used for treating chronic kidney disease (CKD). This study aims to characterize the constituents in SWYST and evaluate the quality based on the quantification of multiple bioactive components. SWYST samples were analyzed with ultra-high-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) and a data-processing strategy. As a result, 215 compounds in SWYST were unambiguously identified or tentatively characterized, including 14 potential new compounds. Meanwhile, strategies based on characteristic fragments for rapid identification were summarized, indicating that the qualitative method is accurate and feasible. Notably, the glucose esters of laccaic acid D-type anthraquinone were first found and their fragmentation patterns were described by comparing that of O-glycoside isomers. Besides, based on comparisons of the cleavage ways of mono-acyl glucose with different acyl groups or acylation sites, differences in fragmentation pathways between 1,2-di-O-acyl glucose and 1,6-di-O-acyl glucose were proposed for the first time and verified by reference substances. In addition, a validated UPLC-DAD was established for the determination of 11 major bioactive components related to treatment of CKD (albiflorin, paeoniflorin, 2,3,5,4'-tetrahydroxy-stilbene-2-O-β-d-glucoside (TSG), 1-O-galloyl-2-O-cinnamoyl-β-d-glucose, emodin-8-O-β-d-glucoside, chrysophanol-O-β-d-glucoside, aloe-emodin, rhein, emodin, chrysophanol and physcion). Moreover, TSG and 1-O-galloyl-2-O-cinnamoyl-β-d-glucose were found as the quality markers related to the origins of SWYST based on multivariate statistical analysis. Conclusively, the findings in this work provide a feasible reference for further studies on quality research and mechanisms of action in treating CKD.

The chemical composition, protective effect of Rheum officinale leaf juice and its mechanism against dextran sulfate sodium-induced ulcerative colitis

BACKGROUND

Rhubarb is widely distributed and cultivated worldwide, and its leaves presented antioxidant activity and could be used as food additive. However, the chemical ingredients, and protective effect of Rheum officinale leaf juice (JROL) on dextran sulfate sodium (DSS)-induced ulcerative colitis (UC) are still unclear.

PURPOSE

This paper sought to the characterization and functional properties of JROL, and explore the underlying mechanism on UC mice.

METHODS

UPLC-ESI-Q-TOF/MS and other analytical instruments were employed to determine the chemical ingredients of JROL. After inducing UC model using 3% DSS, multiple biological methods were used to evaluate its protective effect and the potential mechanism.

RESULTS

JROL is rich in proximate compositions and minerals and has high nutritional value, and contains reducing sugars, polysaccharides and pectin. Fifteen compounds were identified using UPLC-ESI-Q-TOF/MS. Among them, rutin has the highest content (2.22 %) in UPLC analysis. JROL presented protective effect on DSS-induced UC, and alleviated morphological alterations and ultra-structural feature of tissue, and the polysaccharides and flavonoids may contribute to its protective effect. JROL inhibited NF-κB/NLRP3 signaling pathway to alleviate inflammatory response, oxidative stress and intestinal injury by decreasing the expression of p-p65, p-IκBα, NLRP3, ASC, etc.. Moreover, it up-regulated the expression of tight junction proteins, and re-balanced the disturbance of gut microbiota to regulate the inflammatory response. Finally, a correlation among the inflammatory response, NF-κB/NLRP3 pathway and gut microbiota was established. Moreover, JROL presented the safety in the acute toxicity test.

CONCLUSION

JROL could be used as a potential new source for treating UC.

Traditional method of rhubarb processing optimized by combining flavor analysis with anthraquinone content determination

Introduction

Rhubarb is a popular food that relieves constipation and aids with weight loss. The traditional method of preparation, includes steaming and sun-drying rhubarb nine times (SDR-9) to reduce its toxicity and increase efficacy.

Methods

Flavor analysis includes odor analysis by gas chromatography-ion mobility spectrometry and taste characterization using an electronic tongue.

Results

Odor analysis of the samples prepared through SDR-9 identified 61 volatile compounds, including aldehydes, esters, alcohols, ketones, acids, alkenes, and furans. Of these, 13 volatile components were the key substances associated with odor. This enabled the process to be divided into two stages: 1-5 times of steaming and sun-drying and 6-9 times. In the second stage, SDR-6 and SDR-9 were grouped together in terms of odor. Analysis using electronic tongue revealed that the most prominent taste was bitterness. A radar map indicated that the bitterness response was the highest for raw rhubarb, whereas that for processed (steamed and sun-dried) rhubarb decreased. Orthogonal partial least squares discriminant analysis (OPLS-DA) clustering results for SDR-6 and SDR-9 samples indicated that their tastes were similar. Anthraquinones were analyzed via high-performance liquid chromatography; moreover, analysis of the taste and components of the SDR samples revealed a significant correlation.

Discussion

These results indicate that there are similarities between SDR-6 and SDR-9 in terms of smell, taste, and composition, indicating that the steaming and sun-drying cycles can be conducted six times instead of nine.

Exploration of plant metabolomics variation and absorption characteristics of water-extracted Rheum tanguticum and ethanol-extracted Rheum tanguticum by UHPLC-Q-TOF-MS/MS

BACKGROUND AND OBJECTIVE

The herb Rheum tanguticum (RT), a member of the Polygonaceae family, is listed in the Chinese Pharmacopoeia and has been widely used to treat cardiovascular and gastrointestinal disease. The research aimed to identify the different substances from two kinds of RT extraction methods and the in vivo biotransformation of RT components.

METHODS

In this study, by using ultrahigh-performance liquid chromatography coupled with quadrupole-time-of-flight tandem mass spectrometry (UHPLC-Q-TOF-MS/MS), we have investigated the metabolomic variation and the in vivo metabolism of RT. A post-acquisition data processing software, PeakView, was applied to an accurate qualitative analysis of the chemical components in RT.

RESULTS

Through plant metabolomics analysis, 24 related, differentially expressed metabolites of RT water extract and alcohol extract were obtained. Combined with novel identification strategies and systematic in vivo metabolism analysis, a total of 101 compounds were discovered or tentatively identified in rat serum (including 15 prototype compounds and 86 metabolites).

CONCLUSION

In this study, a combination of extraction methods, liquid chromatography-mass spectrometry (LC-MS) technology, and in vivo animal metabolism studies have been established for the screening, identification, and research of chemical active components of natural medicines. LC-MS analysis combined with plant metabolomics was used to study the differential metabolites between different extraction methods of RT. Based on UHPLC-Q-TOF-MS/MS technology, the composition and metabolism of rat plasma before and after RT administration were analysed in vivo, and 15 prototype components and 86 metabolites were detected.

Bidirectional regulation effect of rhubarb as laxative and astringent by metabolomics studies

ETHNOPHARMACOLOGICAL RELEVANCE

Rhubarb, a prominent traditional Chinese medicine, has been employed as a potent laxative for centuries and garnered particular popularity among the youth owing to its notable efficacy in weight management. Historical records indicated that rhubarb initially exhibited robust laxative properties, but extended and consistent usage may lead to an astringent response in the later stage of long-term use. In contrast, steamed pieces of rhubarb (SR), preparing through the process of steaming with wine, have demonstrated a gentle laxative effect with no reported adverse effects.

AIM OF THE STUDY

Our study was designed to explore the intricate mechanisms underlying laxative and astringent properties of rhubarb through metabolomics research.

MATERIALS AND METHODS

In this investigation, we employed a serum metabolomics approach utilizing the UPLC-Q-Extractive-Orbitrap-MS method to delve into the contrasting laxative and astringent effects of rhubarb, as well as to unravel the mechanisms of underpinning its bidirectional regulatory influence. To commence, we assessed alterations in Evacuation Index (EI) values, intestinal hormone levels, and colon histopathology in mice to gauge rhubarb's laxative and astringent effects. Subsequently, metabolomics methodology was employed for cluster analysis through Principal Component Analysis (PCA) and biomarker identification via Orthogonal Partial Least Squares-Discriminant Analysis (OPLS-DA). Then, we delved into the distinctions in characteristic biomarkers, metabolic pathways, their association with pathological changes, and correlation heatmap for biomarkers between raw pieces of rhubarb (RR) and SR to gain insights into the potential mechanisms behind rhubarb's bidirectional regulatory effects.

RESULTS

Our findings revealed that RR exhibited a laxative effect in the early stage and transitioned to an astringent effect in the later stage, as indicated by the EI values. In contrast, SR consistently demonstrated a mild laxative effect. Biochemical indexes and histopathological assessments unveiled that RR triggered its astringent effect by inhibiting secretion of motilin (MTL), promoting secretion of vasoactive intestinal peptide (VIP) and epinephrine (EPI), and inducing onset of inflammation. Furthermore, serum metabolomics analysis identified 59 discriminative biomarkers modulated by RR and SR. Through comprehensive analysis, we elucidated the in vivo transformation relationships among multiple endogenous metabolites. Notably, our results underscored the down-regulation of certain phosphatidylcholines (PCs), amino acids, acylcarnitines, and up-regulation of lysophosphatidylcholines (LysoPCs) played pivotal roles in the onset of gut dysfunction, intestinal inflammation, gut barrier damage, and gastrointestinal motility disorder upon prolonging RR administration, ultimately contributing to its astringent effect. Additionally, our correlation analysis elucidated that anthraquinones, stilbenes, and phenylbutanones were the pharmacodynamic material basis responsible for inducing the astringent effect of RR.

CONCLUSION

This study provides valuable insights into the bidirectional regulatory effects of rhubarb and sheds light on its underlying mechanisms through a comprehensive metabolomics approach.

Anthraquinone Removal from Cassia obtusifolia Seed Water Extract Using Baking, Stir-Frying, and Adsorption Treatments: Effects on the Chemical Composition, Physicochemical Properties of Polysaccharides, and Antioxidant Activities of the Water Extract

Safety issues of the controversial anthraquinones from Cassia obtusifolia seed water extracts (CWEs) limit its application. This work aimed to remove the anthraquinones of CWEs by baking treatment (BT), stir-frying treatment (ST), and adsorption treatment (AT). Effects of these treatments on the chemical composition, physicochemical properties of polysaccharides, and antioxidant activities of CWEs were analyzed and compared. Results indicated that AT exhibited the best removal effect on the total anthraquinone among the three treatments. After AT, the contents of rhein, emodin, aloe-emodin, and aurantio-obtusin of the CWE were below the limit of detection. In addition, AT increased the contents of neutral sugars in CWEs in comparison to BT and ST. None of the treatments had an obvious influence on the structural characteristics of polysaccharides. However, AT decreased the antioxidant activity of CWEs due to their lower anthraquinone content. In summary, AT was considered as an efficient and simple method to remove anthraquinones, while retaining the features of polysaccharides.

Screening and characterization of xenobiotics in rat bio-samples after oral administration of Shen-Wu-Yi-Shen tablet using UPLC-Q-TOF-MS/MS combined with a targeted and non-targeted strategy

Shen-Wu-Yi-Shen tablet (SWYST), a well-known traditional Chinese medicine prescription (TCMP), has been effectively used for treating chronic kidney disease (CKD) in clinically. However, an in-depth study of in vivo metabolism of SWYST is lacking. In this study, a targeted and non-targeted strategy based on ultra-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry (UPLC-Q-TOF-MS/MS) was developed to screen and characterize SWYST-related xenobiotics in rats. Based on the in-house library, a chemical database of SWYST including 215 constituents was constructed through "find by formula" and further verified by characteristic fragmentations or the literatures. Then the constructed chemical database was applied for the targeted screening of prototypes. As for metabolites, the non-targeted screening was achieved combined the peak picking using the function "find by auto-MS/MS" and peak filtration of the prototypes and endogenous components, while the targeted screening was performed using Metabolite ID according to the possible metabolic reactions. Furthermore, the potential metabolites were preliminarily identified by comparison of the parent compounds or references to the literatures. As a result, 201 exogenous components (87 prototypes and 121 metabolites) were characterized in rats after administration of SWYST, including 55 (17 prototypes and 38 metabolites) in plasma, 151 (52 prototypes and 99 metabolites) in urine, and 121 (74 prototypes and 47 metabolites) in feces. Finally, their possible metabolic pathways were summarized, and the metabolic reactions mainly involved phase I reactions (hydroxylation, deoxygenation, hydrogenation, methylation, oxidation, hydrolysis and esterification) and phase II reactions (glucuronidation and sulfation). The findings of this research reveal the potential active ingredients of SWYST, providing an important material basis for the pharmacokinetics and pharmacodynamics of SWYST.

Metabolic profile and dynamic characteristic of rhubarb during the vitro biotransformation by human gut microbiota

Rhubarb is a popular food in the world with laxative effects and steamed pieces of rhubarb (SP) have been widely applied to treatment of constipation in China due to its safety and effectiveness. In the study, metabolism in vitro was conducted to study influence of gut microbiota between raw pieces of rhubarb (RP) and SP. The results showed obvious classifications in metabolic profile between RP and SP were revealed by chemometric analysis, and prompted gut microbiota affected metabolism of rhubarb. Furthermore, 16 characteristic components were identified to distinguish the differences in metabolism. Finally, quantitative analysis of 14 components were verified the regulation of gut microbiota on rhubarb and discovered concentration of components affected the rate of metabolism. The study indicated regulation by gut microbiota could be probably responsible for differences of laxative effects between RP and SP, providing new perspective for exploring mechanisms of effectiveness in clinical application for SP.

High Value-Added Application of Two Renewable Sources as Healthy Food: The Nutritional Properties, Chemical Compositions, Antioxidant, and Antiinflammatory Activities of the Stalks of Rheum officinale Baill. and Rheum tanguticum Maxim. ex Regel

Rhubarb plants (Rheum officinale and R. tanguticum) have edible stalks. In this work, we aimed to compare the nutritional properties, chemical compositions, and bioactivities of R. officinale (SRO) and R. tanguticum (SRT) stalks and to analyze the composition–function relationship. Results showed that the two stalks were good sources of fiber, as well as minerals. They contained abundant essential amino acids and essential fatty acids to regulate the immunity and prevent some chronic diseases; the contents of polyunsaturated fatty acids were 2,244.32 mg/100 g and 2,844.69 mg/100 g, respectively. The antioxidant activity were also proved. Metabolomics showed that SRO and SRT contained abundant phenolic acids. Due to the higher concentrations of flavones, SRT has better antiinflammatory activities than SRO by inhibiting NF-κB signaling pathway. Rhubarb stalks exhibited good safety in acute toxicity and cytotoxicity tests. This work indicated that the two stalks have nutritional value, safety, and bioactivities, and could be used as sources of nutritional ingredients for regulating the immunity of body in food industry.

An efficient approach to probe the bioactive transdermal components of traditional Chinese herbal patches by UHPLC-MS: Gutong patch as a case

BACKGROUND

Traditional Chinese herbal patches (TCHPs) characterized by good patient adherence and few side effects have been widely used in the clinic. However, their bioactive transdermal components, which are key to the quality and efficacy, have rarely been investigated.

PURPOSE

Establishing an approach to probe the bioactive transdermal components of TCHPs, using Gutong patch (GTP) as a case study.

STUDY DESIGN AND METHODS

GTP constituents were identified using ultrahigh-pressure liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-MS). The identified GTP constituents were transferred to an ultrahigh-pressure liquid chromatography coupled with triple quadrupole mass spectrometry (UHPLC-QqQ-MS/MS) method in a dynamic multiple reaction monitoring (dMRM) mode for sensitively targeted analysis of transdermal components present at low concentrations. The ex vivo transdermal components were rapidly probed using a percutaneous permeation model and the release kinetics of marker components was assessed to evaluate the release behavior of GTP. The in vivo transdermal components were then studied in a rat model of arthritis and the changes in concentration of 15 representative bioactive transdermal components with time were well revealed.

RESULTS

A total of 120 phytochemical constituents have been identified in GTP extracts and 61 ex vivo transdermal components were targetedly detected. The release kinetics of GTP were evaluated by eight marker components and fitted to a zero-order kinetic model. In vivo, 62 and 40 transdermal components were observed in the skin and subcutaneous tissues of arthritic rats, respectively. The concentration-time changes of 15 representative transdermal components with documented bioactivities have been successfully exhibited after GTP administration.

CONCLUSION

We established a feasible approach to probe the bioactive transdermal components of TCHPs efficiently. The integration of mass spectrometry profiling and targeted detection in dMRM mode enabled a comprehensive investigation of phytochemical constituents and their transdermal delivery, thus addressing the challenge of direct probing of diverse transdermal components present at low concentrations. This approach could be used to rapidly probe the bioactive components and understand the mechanism of TCHPs.

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.

Study on Hepatotoxicity of Rhubarb Based on Metabolomics and Network Pharmacology

Background

Rhubarb, as a traditional Chinese medicine, is the preferred drug for the treatment of stagnation and constipation in clinical practice. It has been reported that rhubarb possesses hepatotoxicity, but its mechanism in vivo is still unclear.

Methods

In this study, the chemical components in rhubarb were identified based on UPLC-Q-TOF/MS combined with data postprocessing technology. The metabolic biomarkers obtained through metabolomics technology were related to rhubarb-induced hepatotoxicity. Furthermore, the potential targets of rhubarb-induced hepatotoxicity were obtained by network pharmacology involving the above components and metabolites. Meanwhile, GO gene enrichment analysis and KEGG pathway analysis were performed on the common targets.

Results

Twenty-eight components in rhubarb were identified based on UPLC-Q-TOF/MS, and 242 targets related to rhubarb ingredients were predicted. Nine metabolic biomarkers obtained through metabolomics technology were closely related to rhubarb-induced hepatotoxicity, and 282 targets of metabolites were predicted. Among them, the levels of 4 metabolites, namely dynorphin B (10–13), cervonoyl ethanolamide, lysoPE (18:2), and 3-hydroxyphenyl 2-hydroxybenzoate, significantly increased, while the levels of 5 metabolites, namely dopamine, biopterin, choline, coenzyme Q9 and P1, P4-bis (5ʹ-uridyl) tetraphosphate significantly decreased. In addition, 166 potential targets of rhubarb-induced hepatotoxicity were obtained by network pharmacology. The KEGG pathway analysis was performed on the common targets to obtain 46 associated signaling pathways.

Conclusion

These data suggested that rhubarb may cause liver toxicity due to its action on dopamine D1 receptor (DRD1), dopamine D2 receptor (DRD2), phosphodiesterase 4B (PDE4B), vanilloid receptor (TRPV1); transient receptor potential cation channel subfamily M member 8 (TRPM8), prostanoid EP2 receptor (PTGER2), acetylcholinesterase (ACHE), muscarinic acetylcholine receptor M3 (CHRM3) through the cAMP signaling pathway, cholinergic synapses, and inflammatory mediators to regulate TRP channels. Metabolomics technology and network pharmacology were integrated to explore rhubarb hepatotoxicity to promote the reasonable clinical application of rhubarb.

Quality evaluation of rhubarb based on qualitative analysis of the HPLC fingerprint and UFLC-Q-TOF-MS/MS combined with quantitative analysis of eight anthraquinone glycosides by QAMS

Rhubarb is one of the most ancient and important herbal medicines, but its current quality evaluation (QE) methods have some limitations. In this study, a new method was developed for the comprehensive QE of rhubarb. First, fingerprints of 28 batches of three species of rhubarb samples were determined by HPLC, the reference fingerprint was established and the common peaks were assigned. Second, the components of common peaks in the fingerprints were identified by ultrafast liquid chromatography quadrupole time-of-flight mass spectrometry. Finally, a method for the simultaneous determination of the contents of eight anthraquinone glycosides in rhubarb using quantitative analysis of multiple components by a single marker (QAMS) was established, and the contents of these eight components in 28 batches of rhubarb determined by QAMS and the external standard method were compared. The results showed that there were 31 common peaks in the rhubarb fingerprint. The components of these 31 common peaks were identified, and 20 of them were unambiguously confirmed by reference substances, including eight anthraquinone glycosides. The contents of eight anthraquinone glycosides in the 28 batches of rhubarb determined by QAMS and the external standard method were not significantly different. In conclusion, the method established in this study can be used for the comprehensive QE of rhubarb and can also provide a reference for the QE of other herbal medicines.

Multi-marker scans coupled to high-resolution mass spectrometry strategy for global profiling combined with structure recognition of unknown trace chlorogenic acids in Lonicera Flos

Deep investigation, profiling of chemical diversity of constituent compounds and discovery of novel structures is a great challenge. A novel comprehensive and effective approach to mine trace unknown compounds combined with structure recognition in complex matrix is developed, in order to profiling potential Chlorogenic acids (CGAs) in Lonicera Flos (LFs): using multiple neutral loss/precursor ion (NL/PI) markers scans combined with high resolution mass spectrometry (HRMS). The workflow included (i) Fragmentation rules deduced by Q-orbitrap and selection of multiple NL/PI markers. (ii) Multiple NL/PI marker scans and grouping of peaks that had responses on two or more channels. (iii) Alignment of peaks in Full-MS scan and multiple NL/PI scans. (iv) The precursor ions list was introduced to mine novel CGAs according to simulated molecular formula. (v) Identification and structure recognition with the aid of HRMS. The procedure proved to be valid to screen and identify 51 CGAs from Lonicera Flos (LFs) with 16 categories, especially dihydroxyphenyl and glucoside for the first time. Its application could also be extended for global profiling of other complicated chemical systems, such as Chinese medicinal formulas.

A Network Pharmacology Approach to Investigate the Anticancer Mechanism and Potential Active Ingredients of Rheum palmatum L. Against Lung Cancer via Induction of Apoptosis

Rheum palmatum L. (RPL) is a known traditional herbal medicine with the functions of “heat-clearing and damp-drying” in traditional Chinese medicine. Its anti-cancer effect against lung cancer has been confirmed previously, but the related mechanisms and active substances for its action has been little studied. This study adopted the network pharmacology, built the network map of drug ingredients and disease targets (DDN), and discussed the effective components of RPL and its possible mechanisms. All constituents of RPL were collected through database search and literature mining, and the potential active constituents were screened. The inverse pharmacophore matching model was used to predict the targets of active ingredients, and the method was supplemented by database retrieval and literature mining. Compounds-target data were inputted into Cytoscape software to build the DDN of RPL, and functional annotation analysis and pathway enrichment analysis were carried out. Finally, 20 active compounds were screened, which acted on 817 targets. A total of 22,418 lung cancer-related targets were collected, and 761 overlapped with drug targets. By bioinformatics annotation of these overlapping genes, a total of 235 gene ontology (GO) functional annotation analyses and 46 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were obtained. It was found that the enrichment of GO and KEGG was associated with apoptosis, suggesting RPL plays an anti-lung cancer role via inducing cell apoptosis. Subsequent cell experiment results showed RPL and its active constituents inhibited the proliferation of A549 cells and reduced clone formation rate of A549 cells via induction of apoptosis. In this study, the pharmacodynamic basis and mechanism of RPL against lung cancer were studied from the perspective of systematic pharmacology, which would be beneficial for further elucidating the anticancer effect of RPL on lung cancer.

Chemical characterisation and quantification of the major constituents in the Chinese herbal formula Jian-Pi-Yi-Shen pill by UPLC-Q-TOF-MS/MS and HPLC-QQQ-MS/MS

INTRODUCTION

Jian-Pi-Yi-Shen pill (JPYSP) is a Chinese medicine formula developed for the treatment of anaemic patients with chronic kidney disease (CKD).

OBJECTIVE

To investigate the chemical profile of JPYSP in the treatment of renal anaemia.

METHODS

A method coupling ultra-performance liquid chromatography with quadrupole time-of-flight tandem mass spectrometry (UPLC-Q-TOF-MS/MS) was established to characterise the chemical constituents present in JPYSP. Subsequently, a high-performance liquid chromatography method coupled with triple-quadrupole tandem mass spectrometry (HPLC-QQQ-MS/MS) was developed to quantify the major constituents from the identified compounds related to the treatment of CKD and anaemia.

RESULTS

A total of 71 compounds were tentatively identified from JPYSP, including saponins, flavonoids, sesquiterpenoids, coumarins, phenylpropanoids, anthranones, anthraquinones, tannins, phenolic acids and others. Amongst them, 12 compounds (i.e. astragaloside IV, calycosin, calycosin 7-O-glucoside, salvianolic acid A, rosmarinic acid, rhein, liquiritin, formononetin, atractylenolide I, dioscin, tanshinone IIA, and acteoside) were further quantified simultaneously by HPLC-QQQ-MS/MS.

CONCLUSION

The newly developed approach is suitable for the chemical profiling analysis and quality control of JPYSP, and could lead to additional pharmacodynamic studies involving the components of JPYSP.

What we already know about rhubarb: a comprehensive review

Rhubarb (also named Rhei or Dahuang), one of the most ancient and important herbs in traditional Chinese medicine (TCM), belongs to the Rheum L. genus from the Polygonaceae family, and its application can be traced back to 270 BC in "Shen Nong Ben Cao Jing". Rhubarb has long been used as an antibacterial, anti-inflammatory, anti-fibrotic and anticancer medicine in China. However, for a variety of reasons, such as origin, variety and processing methods, there are differences in the effective components of rhubarb, which eventually lead to decreased quality and poor efficacy. Additionally, although some papers have reviewed the relationship between the active ingredients of rhubarb and pharmacologic actions, most studies have concentrated on one or several aspects, although there has been great progress in rhubarb research in recent years. Therefore, this review aims to summarize recent studies on the geographic distribution, taxonomic identification, pharmacology, clinical applications and safety issues related to rhubarb and provide insights into the further development and application of rhubarb in the future.

Comparison of Chemometric Problems in Food Analysis Using Non-Linear Methods

Food analysis is a challenging analytical problem, often addressed using sophisticated laboratory methods that produce large data sets. Linear and non-linear multivariate methods can be used to process these types of datasets and to answer questions such as whether product origin is accurately labeled or whether a product is safe to eat. In this review, we present the application of non-linear methods such as artificial neural networks, support vector machines, self-organizing maps, and multi-layer artificial neural networks in the field of chemometrics related to food analysis. We discuss criteria to determine when non-linear methods are better suited for use instead of traditional methods. The principles of algorithms are described, and examples are presented for solving the problems of exploratory analysis, classification, and prediction.

Exploring the Therapeutic Composition and Mechanism of Jiang-Suan-Chu-Bi Recipe on Gouty Arthritis Using an Integrated Approach Based on Chemical Profile, Network Pharmacology and Experimental Support Using Molecular Cell Biology

Background

Gouty arthritis is a common metabolic disease caused by long-term purine metabolic disorder and elevated serum uric acid. Jiang-Suan-Chu-Bi recipe (JSCBR), a traditional Chinese herbal formula prescribed according to utilization frequency and cluster analysis, has been clinically validated remedy for gouty arthritis. However, its therapeutic composition and mechanism remains unclear.

Methods

In the present study, a simple, rapid, and sensitive ultraperformance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-MS)-based chemical profiling was firstly established for comprehensively identifying the major constituents in JSCBR. A phytochemistry-based network pharmacology analysis was further performed to explore the potential therapeutic targets and pathways involved in JSCBR bioactivity. Finally, THP-1 cell model was used to verify the prediction results of network pharmacology by western blot analysis.

Results

A total of 139 compounds containing phenolic acids, flavonoids, triterpenoid saponins, alkaloids, amino acids, fatty acids, anthraquinones, terpenes, coumarins, and other miscellaneous compounds were identified, respectively. 175 disease genes, 51 potential target nodes, 80 compounds, and 11 related pathways based on network pharmacology analysis were achieved. Among these pathways and genes, NOD-like receptor signaling pathway may play an important role in the curative effect of JSCBR on gouty arthritis by regulation of NRLP3/ASC/CASP1/IL1B. The results of cellular and molecular experiments showed that JSCBR can effectively reduce the protein expression of ASC, caspase-1, IL-1β, and NRLP3 in monosodium urate-induced THP-1 cells, which indicated that JSCBR mediated inflammation in gouty arthritis by inhibiting the activation of NOD-like receptor signaling pathway.

Conclusion

Thus, the integrated approaches adopted in the present study could contribute to simplifying the complex system and providing directions for further research of JSCBR.

Rapid characterization of the chemical constituents of Sanhua decoction by UHPLC coupled with Fourier transform ion cyclotron resonance mass spectrometry

Sanhua decoction, a famous Chinese herbal formula has been widely used for the treatment of stroke. In our study, a rapid, swift and straightforward analytical method with the help of UHPLC-FT-ICR-MS/MS was successfully developed for the first time to separate and identify the chemical constituents of Sanhua decoction. Chromatography was performed on a Universal XB C₁₈ column (150 mm × 2.1 mm, 1.8 μm) using a mobile phase containing 0.1% formic acid–water (A) and acetonitrile (B). A total of 137 compounds in Sanhua decoction were identified or tentatively characterized. The findings revealed the fact that Sanhua decoction mainly contains flavonoids (in Aurantii fructus immaturus and Rheum palmatum L.), anthraquinones (in Rheum palmatum L.), coumarins (in Notopterygii Rhizoma Et Radix), phenylpropanoid glycosides, alkaloids and lignans (in Magnoliae Officmalis Cortex), which made up the key ingredients existing in Sanhua decoction. This study is hoped to be meaningful for the characterization of components in other traditional Chinese medicines, and lay the foundation for research on the pharmacology of Sanhua decoction.

Sanhua decoction, a famous Chinese herbal formula has been widely used for the treatment of stroke.

An integrated strategy based on characteristic fragment filter supplemented by multivariate statistical analysis in multi-stage mass spectrometry chromatograms for the large-scale detection and identification of natural plant-derived components in rat: The rhubarb case

An integrated strategy based on characteristic fragment filter (CFF) supplemented by multivariate statistical analysis (MSA) for MSⁿ chromatograms [(CFF)s MSA] was proposed for the large-scale detection of natural plant-derived ingredients in vivo. To prove the practicability of this [(CFF)s MSA] strategy, rhubarb was taken as an example. First, representative authentic standards of homologous components contained in rhubarb were chosen, from which the fragmentation rules and chemical characteristic fragments (CCFs) were proposed. Second, the metabolic pathways of the representative compounds were deciphered, and the metabolic characteristic fragments (MCFs) of each family of compounds were acquired. Third, combined with CCFs and MCFs, a CFF method was established. Finally, MSA was used to supplement the xenobiotics missed by the CFF method. In our research, 274 compounds were detected in rhubarb, and 298 ingredients were identified in vivo after oral administration. The results demonstrated that this integrated strategy could comprehensively screen for plant-derived compounds in vivo.

Protic Ionic Liquids as Efficient Solvents in Microwave-Assisted Extraction of Rhein and Emodin from Rheum palmatum L

Rheum palmatum L. (R. palmatum L.) is a traditional Chinese herb and food, in which rhein and emodin are the main bioactive components. The extraction of the two compounds from R. palmatum L. is, thus, of great importance. In this work, protic ionic liquids (PILs) were applied in the microwave-assisted extraction (MAE) of rhein and emodin from R. palmatum L., which avoids the toxicity of organic solvents. The results of the present study indicate that PILs possessing higher polarity exhibit higher extraction ability due to their stronger absorption ability for microwave irradiation. Compared with conventional solvents, such as methanol, trichloromethane, and deep eutectic solvents (DESs), the PIL, 1-butyl-3-himidazolium methanesulfonate ([BHim]MeSO3) reported herein is more efficient. The selected extraction conditions of liquid-solid ratio, microwave irradiation time, microwave irradiation power, and PIL concentration were 40 g·g-1, 50 s, 280 W, and 80%, respectively. Under the selected conditions, the extraction yields of rhein and emodin were 7.8 and 4.0 mg·g-1, respectively. These results suggest that PILs are efficient extraction solvents for the separation of active components from natural products.

Application of multifold characteristic ion filtering combined with statistical analysis for comprehensive profiling of chemical constituents in anti-renal interstitial fibrosis I decoction by ultra-high performance liquid chromatography coupled with hybrid quadrupole-orbitrap high resolution mass spectrometry

A Chinese herbal formula of Anti-Renal Interstitial Fibrosis I Decoction (ARIF I) is composed of Eucommia ulmoides Oliv., Scutellaria baicalensis Georgi, and Rheum. officinale Baill., and it has been used for the treatment of chronic kidney disease for many years. However, the comprehensive chemical analysis of the formulated ARIF I has yet to be clarified. In this study, an ultra-high performance liquid chromatography coupled with hybrid quadrupole-orbitrap high resolution mass spectrometry (UHPLC/Q-orbitrap HRMS) method executed in full scan/data-dependent MS² (full MS/dd-MS²) mode has been established in negative ion mode to analyze the major chemical constituents in ARIF I as well as in its three constituent herbs. To rapidly and efficient identify these compounds, we employed a combination of statistical analysis of the MS² data and fragmentation pathway method to screen for elementary characteristic ions and sub-characteristic ions. Then, we applied multifold characteristic ion filtering to comprehensively profile ARIF I extract chemical constituents with diverse structures. A total of 360 compounds, including anthraquinones, sennosides, galloyl glucoside derivatives, catechin and its derivatives, flavonoids, iridoids, phenylpropanoids, lignan, organic acid, and other compounds were rapidly identified or tentatively characterized by multifold characteristic ion filtering based on their accurate mass spectra (within 5 ppm error) and structure types or by comparison with reference standards. All the ARIF I compounds were also detected in the individual constituent herbs. This study provides a basis for further pharmacokinetic studies of ARIF I and may help in the discovery of new chemical drugs to treat chronic kidney disease. This study also provides a more efficient approach for the screening of appropriate characteristic ions, and a practical strategy for the detection of the types of compounds identified in this study in other herbal medicines.

A Study on Tissue-Specific Metabolite Variations in Polygonum cuspidatum by High-Resolution Mass Spectrometry-Based Metabolic Profiling

Polygonum cuspidatum Sieb. et Zucc. is a traditional Chinese herbal medicine widely used to treat tussis, hepatitis and arthralgia. This study identified and quantitatively described the bioactive compounds in different P. cuspidatum tissues. Metabolic profiles of root, stem, leaf, flower, rhizome and seed were determined using high-resolution mass spectrometry in combination with multivariate analyses. In total, 53 metabolites, 8 reported for the first time in this species, were putatively identified and classified mainly as stilbenes, anthraquinones and flavonoids. A principal component analysis, cluster analysis and heatmap were used to depict the correlations between specimens and the relative abundance levels of these compounds in different plant tissues. An orthogonal partial least square discriminant analysis found that 13 metabolites showed distinct differences among the six plant tissues, making them potential discriminative tissue-identification markers. This study will provide guidance in comparing, selecting and exploiting the medicinal uses of different P. cuspidatum tissues.

HPLC-PDA Combined with Chemometrics for Quantitation of Active Components and Quality Assessment of Raw and Processed Fruits of Xanthium strumarium L

As a valuable herbal medicine, the fruits of Xanthium strumarium L. (Xanthii Fructus) have been widely used in raw and processed forms to achieve different therapeutic effects in practice. In this study, a comprehensive strategy was proposed for evaluating the active components in 30 batches of raw and processed Xanthii Fructus (RXF and PXF) samples, based on high-performance liquid chromatography coupled with photodiode array detection (HPLC-PDA). Twelve common peaks were detected and eight compounds of caffeoylquinic acids were simultaneously quantified in RXF and PXF. All the analytes were detected with satisfactory linearity (R² > 0.9991) over wide concentration ranges. Simultaneously, the chemically latent information was revealed by hierarchical cluster analysis (HCA) and principal component analysis (PCA). The results suggest that there were significant differences between RXF and PXF from different regions in terms of the content of eight caffeoylquinic acids. Potential chemical markers for XF were found during processing by chemometrics.

Seeing the unseen of Chinese herbal medicine processing (Paozhi): advances in new perspectives

Processing (Paozhi) represents a unique Chinese pharmaceutic technique to facilitate the use of Chinese herbal medicines (CHMs) for a specific clinical need in the guidance of Traditional Chinese Medicine (TCM) theory. Traditionally, most CHMs require a proper processing to meet the needs of specific clinical syndromes before being prescribed by TCM practitioners. During processing, significant changes in chemical profiles occur, which inevitably influence the associated pharmacological properties of a CHM. However, although processing is formed in a long-term practice, the underlying mechanisms remain unclear for most CHMs. The deepening understanding of the mechanism of processing would provide scientific basis for standardization of processing. This review introduced the role of processing in TCM and several typical methods of processing. We also summarized the up-to-date efforts on the mechanistic study of CHM processing. The processing mechanisms mainly include the following aspects: (i) directly reducing contents of toxic constituents; (ii) structural transformation of constituents; (iii) improving solubility of constituents; (iv) physically changing the existing form of constituents; (v) and influence by excipients. These progress may give new insights into future researches.

Natural deep eutectic solvents as new green solvents to extract anthraquinones from Rheum palmatum L

Natural deep eutectic solvents (NADESs) are efficient in extracting natural products. However, traditional organic solvents are toxic in the extraction of anthraquinones from Rheum palmatum L. To solve this problem, we applied natural deep eutectic solvent ultrasound-assisted extraction in this study for the extraction of total anthraquinones from R. palmatum L. Principal component analysis revealed that the selected NADES which consisted of lactic acid, glucose and water (LGH), was highly efficient in extracting anthraquinones from R. palmatum L. The ratio of lactic acid/glucose and the addition of water in LGH were investigated via a single-factor experiment. With a lactic acid/glucose ratio of 5 : 1 (mol/mol), and 10% of water (v/v), LGH had a high extraction yield to anthraquinones. Optimized by response surface methodology (RSM), the optimized extraction conditions of extraction time, extraction temperature and solvent-to-solid ratio of 1.5 h, 82 °C and 26 mL g⁻¹, respectively. Under optimum conditions, the extraction yields of aloe-emodin, rhein, emodin, chrysophanol, physcion and total anthraquinones were 2.60 ± 0.01, 5.78 ± 0.02, 2.21 ± 0.02, 5.87 ± 0.02, 8.81 ± 0.01 and 25.27 ± 0.07 mg g⁻¹, respectively. The enrichment and separation of five anthraquinones in LGH extraction solution were efficiently achieved using DM130 macroporous resin, with purities of 90.98%, 96.67%, 92.37%, 95.80% and 91.61% as indicated by HPLC, and recovery yields of 84.08%, 79.51%, 84.96%, 81.83% and 78.35%, respectively. LGH was environmentally friendly and highly efficient in extracting anthraquinones from R. palmatum L., and NADESs showed potential for the extraction of effective components from natural products.

Natural deep eutectic solvents ultrasound-assisted extraction (NADES-UAE) was applied to extract total anthraquinones from Rheum palmatum L.

Analysis of Chemical Variations between Crude and Salt-Processed Anemarrhenae rhizoma Using Ultra-High-Performance Liquid Chromatography-Mass Spectrometry Methods

The present study was designed to systematically investigate the chemical profile differences between crude Anemarrhenae rhizoma (CAR) and salt-processed Anemarrhenae rhizoma (SAR). Ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-MS), coupled with multivariate statistical analysis was used for the discrimination of chemical profiles and the identification of the differentiation of the chemical constitutions of CAR and SAR. In addition, seven main constituents of CAR and SAR were simultaneously determined by ultra-high-performance liquid chromatography-quadrupole mass spectrometry (UHPLC-MS) for analyzing the content variations. A total of 24 components were found to be the main contributors to the significant difference between CAR and SAR. The structures of the marker compounds were identified based on their chromatographic behaviors, intact precursor ions, and characteristic MS fragmentation patterns. The potential structural transformation mechanism of furostanol saponins during salt processing was explored. The results may provide a scientific foundation for deeply elucidating the processing mechanism of Anemarrhenae rhizoma.

Bioassay guided screening, optimization and characterization of antioxidant compounds from high altitude wild edible plants of Ladakh

Seven edible plants including three unexplored species of high altitude (Ladakh) region were screened for antioxidant activity by bioassay guided fractionation method. The objective of the study was to dereplicate the complex phytochemical matrix of a plant in reference to antioxidant activity in vitro. The screening result showed that ethylacetate fraction of Nepeta longibracteata possesses maximum antioxidant activity, comparable to that of green tea. It also exhibited significant protecting effect against oxidative stress induced by t-BHP in human RBCs. Phytochemical profiling of the most active fraction by nontargeted RP-HPLC-MS and MS/MS technique showed that rosmarinic acid and methylrosmarinate constituted nearly 51 % of the total metabolites apart from twelve other major chemotypes.

Nontargeted diagnostic ion network analysis (NINA): A software to streamline the analytical workflow for untargeted characterization of natural medicines

The characterization of herbal prescriptions serves as a foundation for quality control and regulation of herbal medicines. Previously, the characterization of herbal chemicals from natural medicines often relied on the analysis of signature fragment ions from the acquired tandem mass spectrometry (MS/MS) spectra with prior knowledge of the herbal species present in the herbal prescriptions of interest. Nevertheless, such an approach is often limited to target components, and it risks missing the critical components that we have no prior knowledge of. We previously reported a "diagnostic ion-guided network bridging" strategy. It is a generally applicable and robust approach to analyze unknown substances from complex mixtures in an untargeted manner. In this study, we have developed a standalone software named "Nontargeted Diagnostic Ion Network Analysis (NINA)" with a graphical user interface based on a strategy for post-acquisition data analysis. NINA allows one to rapidly determine the nontargeted diagnostic ions (NIs) by summarizing all of the fragment ions shared by the precursors from the acquired MS/MS spectra. A NI-guided network using bridging components that possess two or more NIs can then be established via NINA. With such a network, we could sequentially identify the structures of all the NIs once a single compound has been identified de novo. The structures of NIs can then be used as "priori" knowledge to narrow the candidates containing the sub-structure of the corresponding NI from the database hits. Subsequently, we applied the NINA software to the characterization of a model herbal prescription, Re-Du-Ning injection, and rapidly identified 56 herbal chemicals from the prescription using an ultra-performance liquid chromatography quadrupole time-of-flight system in the negative mode with no knowledge of the herbal species or herbal chemicals in the mixture. Therefore, we believe the applications of NINA will greatly facilitate the characterization of complex mixtures, such as natural medicines, especially when no advance information is available. In addition to herbal medicines, the NINA-based workflow will also benefit many other fields, such as environmental analysis, nutritional science, and forensic analysis.

HPLC-TOF-MS and HPLC-MS/MS combined with multivariate analysis for the characterization and discrimination of phenolic profiles in nonfumigated and sulfur-fumigated rhubarb

Sulfur fumigation has recently been used during the postharvest handling of rhubarb to reduce the drying duration and control pests. However, a few reports question the effect of sulfur fumigation on the bioactive components of rhubarb, which is crucial for the quality evaluation of the herbal medicine. The bottleneck limiting the study comes from the complex compounds that exist in herb samples with diverse structural features, wide concentration range and the difficulty to obtain all the reference standards. In this study, an integrated strategy based on the highly effective separation and analysis by liquid chromatography coupled with diode-array detection and time-of-flight/triple-quadruple tandem mass spectrometry combined with multivariate analysis was established. 68 phenolic compounds that exist in nonfumigated and sulfur-fumigated herb samples of rhubarb were tentatively assigned based on their retention behavior, UV spectra, accurate molecular weight, and mass spectral fragments. Qualitative and semiquantitative comparison revealed a serious reduction of the majority of phenolic compounds in sulfur-fumigated rhubarb. Furthermore, multivariate analysis was applied to holistically discriminate nonfumigated from sulfur-fumigated rhubarb and explore the characteristic chemical markers. The established approach was specific and rapid for characterizing and screening sulfur-fumigated rhubarb among commercial samples and could be applied for the quality assessment of other sulfur-fumigated herbs.

Types, principle, and characteristics of tandem high-resolution mass spectrometry and its applications

We review the principle and functional characteristics of different types or models for THRMS and provide a brief description of its applications in medical research, food safety, and environmental protection fields.