Sinapine detection in radish taproot using surface desorption atmospheric pressure chemical ionization mass spectrometry

Revealing the potential bioactive components and mechanism of Qianhua Gout Capsules in the treatment of gouty arthritis through network pharmacology, molecular docking and pharmacodynamic study strategies

Recent clinical studies have confirmed the effectiveness of Qianhua Gout Capsules (QGC) in the treatment of gouty arthritis (GA). However, the specific regulatory targets and mechanisms of action of QGC are still unclear. To address this gap, we utilized network pharmacology, molecular docking, and pharmacodynamic approaches to investigate the bioactive components and associated mechanisms of QGC in the treatment of GA. By employing UPLC-Q Exactive-MS, we identified the compounds present in QGC, with active ingredients defined as those with oral bioavailability ≥30 % and drug similarity ≥0.18. Subsequently, the targets of these active compounds were determined using the TCMSP database, while GA-related targets were identified from DisGeNET, GeneCards, TTD, OMIM, and DrugBank databases. Further analysis including PPI analysis, GO analysis, and KEGG pathway enrichment was conducted on the targets. Validation of the predicted results was performed using a GA rat model, evaluating pathological changes, inflammatory markers, and pathway protein expression. Our results revealed a total of 130 components, 44 active components, 16 potential shared targets, GO-enriched terms, and 47 signaling pathways related to disease targets. Key active ingredients included quercetin, kaempferol, β-sitosterol, luteolin, and wogonin. The PPI analysis highlighted five targets (PPARG, IL-6, MMP-9, IL-1β, CXCL-8) with the highest connectivity, predominantly enriched in the IL-17 signaling pathway. Molecular docking experiments demonstrated strong binding of CXCL8, IL-1β, IL-6, MMP9, and PPARG targets with the top five active compounds. Furthermore, animal experiments confirmed the efficacy of QGC in treating GA in rats, showing reductions in TNF-α, IL-6, and MDA levels, and increases in SOD levels in serum. In synovial tissues, QGC treatment upregulated CXCL8 and PPARG expression, while downregulating IL-1β, MMP9, and IL-6 expression. In conclusion, this study applied a network pharmacology approach to uncover the composition of QGC, predict its pharmacological interactions, and demonstrate its in vivo efficacy, providing insights into the anti-GA mechanisms of QGC. These findings pave the way for future investigations into the therapeutic mechanisms underlying QGC's effectiveness in the treatment of GA.

Dual ambient plasma source ionization mass spectrometry for the rapid detection of trace sterols in urban water: Rapid detection of trace sterols in urban water

A direct analytical method based on dual ambient plasma ion source tandem mass spectrometry was used for the simultaneous determination of four sterols in the environment. This technology has very high sensitivity and the method detects the four sterols in methanol-water (1:3) solutions with limits of detection (LOD) and limits of quantification (LOQ) ranging from 1.2 ng/L to 6.9 ng/L and 7.6 ng/L to 10.0 ng/L, respectively. The method was also used to test water quality at three locations within the city and successfully detected all four sterols at very low concentrations. The dual plasma source tandem mass spectrometry technique is extremely simple, rapid, sensitive and highly efficient compared to other traditional methods, providing a useful screening tool for sterols in water.

Development of a miniature protein mass spectrometer capable of analyzing native proteins

Current miniature mass spectrometers were usually designed for the detection of small and medium size molecules, including volatile (semi-volatile) compounds, drugs and lipids. In this study, a miniature protein mass spectrometer was developed in this work, which could serve as a biosensor for the rapid identification of proteins as well as their conformations. A linear ion trap with a field radius of 2.5 mm was designed to extend mass range of the instrument to over 6500 Th. Mass resolution and sensitivity of the instrument were also optimized for protein ions by increasing the buffer gas pressure and using a high-gain Faraday detector. It is then demonstrated that the mass spectra of native proteins, such as IgG1, could be acquired by coupling the instrument with a soft electrospray ionization source. As a proof-of-concept demonstration, results suggest that the current instrument could be used to identify target proteins and probe/distinguish their conformations in solutions.

Evaluation of the phytotoxicity of nano-particles on mung beans by internal extractive electrospray ionization mass spectrometry

The wide application of nano-particles (NPs) has raised a serious concern over their impact on plants. However, evaluation of the effects of NPs on plant metabolism by direct detection of chemicals inside solid tissues presents a challenge. In this study, we report on a direct ionization method in mass spectrometry, internal extractive electrospray ionization (iEESI), for the direct evaluation of phytotoxicity of three different NPs (including CdTe quantum dots (CdTe QDs), gold nano-particles (Au NPs), and silver nano-particles (Ag NPs)) both on surfaces and inside solid tissues from the mung bean seeds (Vigna radiata) that were cultured in aqueous solutions of three NPs at 50 μg mL^-1. The results showed that NPs could stimulate the biological accumulation of trigonelline and the decomposition of polysaccharides/oligosaccharides to glucose and maltose within 21 h of culture. To the best of our knowledge, this is the first study to apply internal extractive electrospray ionization mass spectrometry (iEESI-MS) for the direct measurement of solid tissue samples to evaluate the phytotoxicity of NPs on mung bean sprouts. Our study lays a solid foundation for further examination of other NPs-induced damaging effects such as apoptosis/necrosis, helping us to understand the phytotoxicity of NPs on plants.

Sinapine Thiocyanate Ameliorates Vascular Endothelial Dysfunction in Hypertension by Inhibiting Activation of the NLRP3 Inflammasome

The increase of blood pressure is accompanied by the changes in the morphology and function of vascular endothelial cells. Vascular endothelial injury and hypertension actually interact as both cause and effect. A large number of studies have proved that inflammation plays a significant role in the occurrence and development of hypertension, but the potential mechanism between inflammation and hypertensive endothelial injury is still ambiguous. The purpose of this study was to explore the association between the activation of NLRP3 inflammasome and hypertensive endothelial damage, and to demonstrate the protective effect of sinapine thiocyanate (ST) on endothelia in hypertension. The expression of NLRP3 gene was silenced by tail vein injection of adeno-associated virus (AAVs) in spontaneously hypertensive rats (SHRs), indicating that activation of NLRP3 inflammasome accelerated hypertensive endothelial injury. ST not only protected vascular endothelial function in SHRs by inhibiting the activation of NLRP3 inflammasome and the expression of related inflammatory mediators, but also improved AngII-induced huvec injury. In summary, our results show that alleviative NLRP3 inflammasome activation attenuates hypertensive endothelial damage and ST ameliorates vascular endothelial dysfunction in hypertension via inhibiting activation of the NLRP3 inflammasome.

A cationic conjugated polymer and graphene oxide: Application to amplified fluorescence detection of sinapine

An amplified fluorescence strategy is described for the detection of sinapine (SP) by using a cationic conjugated polymer (PFP) and graphene oxide (GO). It is observed that the fluorescein (FAM)-labeled single-stranded DNA (FAM-DNA) is absorbed on the surface of GO if SP is absent. This causes that fluorescence resonance energy transfer (FRET) from PFP to FAM is inefficient when adding PFP into FAM-DNA/GO complex. If SP is added to FAM-DNA/GO complex, FAM-DNA is desorbed from GO surface due to the competitive binding of SP and FAM-DNA toward GO. In this case, FAM-DNA is close to PFP in the presence of PFP through strong electrostatic interaction, leading to the occurrence of efficient FRET. Based on the above phenomenon, we demonstrate a method to amplify fluorescence signal of traditional GO-based SP assay by introducing PFP. In comparison to the use of single GO, the combination of PFP with GO-based strategy displays high turn-on ratio and enhanced sensitivity with a limit of detection as low as 7.3 ng mL^-1 for SP detection. Satisfactory results in practical samples are also obtained by the recovery experiments, demonstrating the potential application of cationic conjugated polymer in plant-derived small molecule.

Molecular differentiation of five Cinnamomum camphora chemotypes using desorption atmospheric pressure chemical ionization mass spectrometry of raw leaves

Five chemotypes, the isoborneol-type, camphora-type, cineole-type, linalool-type and borneol-type of Cinnamomum camphora (L.) Presl have been identified at the molecular level based on the multivariate analysis of mass spectral fingerprints recorded from a total of 750 raw leaf samples (i.e., 150 leaves equally collected for each chemotype) using desorption atmospheric pressure chemical ionization mass spectrometry (DAPCI-MS). Both volatile and semi-volatile metabolites of the fresh leaves of C. camphora were simultaneously detected by DAPCI-MS without any sample pretreatment, reducing the analysis time from half a day using conventional methods (e.g., GC-MS) down to 30 s. The pattern recognition results obtained using principal component analysis (PCA) was cross-checked by cluster analysis (CA), showing that the difference visualized by the DAPCI-MS spectral fingerprints was validated with 100% accuracy. The study demonstrates that DAPCI-MS meets the challenging requirements for accurate differentiation of all the five chemotypes of C. camphora leaves, motivating more advanced application of DAPCI-MS in plant science and forestry studies.

Graphene oxide-based fluorescent sensor for sensitive turn-on detection of sinapine

Sinapine (SP) has attracted extensive attention in food and medical field because it is a crucial component in many plants with unique physiological activities. Here, we reported a fluorescent sensor based on the unique properties of graphene oxide (GO) for rapid, sensitive detection of SP concentration. In this strategy, GO has stronger affinity toward SP and can be also served as a quencher for DNA fluorescence probe. The fluorescence can make a recovery by the addition of SP, which can competitively desorb probe from the surface of GO, and the SP can thus be monitored by recording the fluorescence change. Because of the low background assays and high quenching ability offered by GO, the developed method provides a great potential for plant-derived molecules research.

Applications of DART-MS for food quality and safety assurance in food supply chain

Direct analysis in real time (DART) represents a new generation of ion source which is used for rapid ionization of small molecules under ambient conditions. The combination of DART and various mass spectrometers allows analyzing multiple food samples with simple or no sample treatment, or in conjunction with prevailing protocolized sample preparation methods. Abundant applications by DART-MS have been reviewed in this paper. The DART-MS strategy applied to food supply chain (FSC), including production, processing, and storage and transportation, provides a comprehensive solution to various food components, contaminants, authenticity, and traceability. Additionally, typical applications available in food analysis by other ambient ionization mass spectrometers were summarized, and fundamentals mainly including mechanisms, devices, and parameters were discussed as well. © 2015 Wiley Periodicals, Inc. Mass Spec Rev. 36:161-187, 2017.

Differential diagnosis of human lung tumors using surface desorption atmospheric pressure chemical ionization imaging mass spectrometry

Differential diagnosis of human lung cancer in untreated tissue is achieved by DAPCI-MSI combined with multivariate statistical analysis.

In situ Identification of Labile Precursor Compounds and their Short-lived Intermediates in Plants using in vivo Nanospray High-resolution Mass Spectrometry

INTRODUCTION

Many secondary metabolites in plants are labile compounds which under environmental stress, are difficult to detect and track due to the lack of rapid in situ identification techniques, making plant metabolomics research difficult. Therefore, developing a reliable analytical method for rapid in situ identification of labile compounds and their short-lived intermediates in plants is of great importance.

OBJECTIVE

To develop under atmospheric pressure, a rapid in situ method for effective identification of labile compounds and their short-lived intermediates in fresh plants.

METHODOLOGY

An in vivo nanospray high-resolution mass spectrometry (HR-MS) method was used for rapid capture of labile compounds and their short-lived intermediates in plants. A quartz capillary was partially inserted into fresh plant tissues, and the liquid flowed out through the capillary tube owing to the capillary effect. A high direct current (d.c.) voltage was applied to the plant to generate a spray of charged droplets from the tip of the capillary carrying bioactive molecules toward the inlet of mass spectrometer for full-scan and MS/MS analysis.

RESULTS

Many labile compounds and short-lived intermediates were identified via this method: including glucosinolates and their short-lived intermediates (existing for only 10 s) in Raphanus sativus roots, alliin and its conversion intermediate (existing for 20 s) in Allium sativum and labile precursor compound chlorogenic acid in Malus pumila Mill.

CONCLUSION

The method is an effective approach for in situ identification of internal labile compounds and their short-lived intermediates in fresh plants and it can be used as an auxiliary tool to explore the degradation mechanisms of new labile plant compounds. Copyright © 2016 John Wiley & Sons, Ltd.

Molecular Ionization-Desorption Analysis Source (MIDAS) for Mass Spectrometry: Thin-Layer Chromatography

Molecular ionization-desorption analysis source (MIDAS), which is a desorption atmospheric pressure chemical ionization (DAPCI) type source, for mass spectrometry has been developed as a multi-functional platform for the direct sampling of surfaces. In this article, its utility for the analysis of thin-layer chromatography (TLC) plates is highlighted. Amino acids, which are difficult to visualize without staining reagents or charring, were detected and identified directly from a TLC plate. To demonstrate the full potential of MIDAS, all active ingredients from an analgesic tablet, separated on a TLC plate, were successfully detected using both positive and negative ion modes. The identity of each of the compounds was confirmed from their mass spectra and compared against standards. Post separation, the chemical signal (blue permanent marker) as reference marks placed at the origin and solvent front were used to calculate retention factor (Rf) values from the resulting ion chromatogram. The quantitative capabilities of the device were exhibited by scanning caffeine spots on a TLC plate of increasing sample amount. A linear curve based on peak are, R2 = 0.994, was generated for seven spots ranging from 50 to 1000 ng of caffeine per spot.

Plasma-based ambient ionization mass spectrometry in bioanalytical sciences

Plasma-based ambient ionization mass spectrometry techniques are gaining growing interest due to their specific features, such as the need for little or no sample preparation, its high analysis speed, and the ambient experimental conditions. Samples can be analyzed in gas, liquid, or solid forms. These techniques allow for a wide range of applications, like warfare agent detection, chemical reaction control, mass spectrometry imaging, polymer identification, and food safety monitoring, as well as applications in biomedical science, e.g., drug and pharmaceutical analysis, medical diagnostics, biochemical analysis, etc. Until now, the main drawback of plasma-based techniques is their quantitative aspect, but a lot of efforts have been done to improve this obstacle.

Mass spectrometry imaging for visualizing organic analytes in food

The demand for rapid chemical imaging of food products steadily increases. Mass spectrometry (MS) is featured by excellent molecular specificity of analysis and is, therefore, a very attractive method for chemical profiling. MS for food imaging has increased significantly over the past decade, aided by the emergence of various ambient ionization techniques that allow direct and rapid analysis in ambient environment. In this article, the current status of food imaging with MSI is reviewed. The described approaches include matrix-assisted laser desorption/ionization (MALDI), but emphasize desorption atmospheric pressure photoionization (DAPPI), electrospray-assisted laser desorption/ionization (ELDI), probe electrospray ionization (PESI), surface desorption atmospheric pressure chemical ionization (SDAPCI), and laser ablation flowing atmospheric pressure afterglow (LA-FAPA). The methods are compared with regard to spatial resolution; analysis speed and time; limit of detection; and technical aspects. The performance of each method is illustrated with the description of a related application. Specific requirements in food imaging are discussed.

Characterization of a Direct Sample Analysis (DSA) Ambient Ionization Source

Water cluster ion intensity and distribution is affected by source conditions in direct sample analysis (DSA) ionization. Parameters investigated in this paper include source nozzle diameter, gas flow rate, and source positions relative to the mass spectrometer inlet. Schlieren photography was used to image the gas flow profile exiting the nozzle. Smaller nozzle diameters and higher flow rates produced clusters of the type [H + (H(2)O)(n)](+) with greater n and higher intensity than larger nozzles and lower gas flow rates. At high gas flow rates, the gas flow profile widened compared with the original nozzle diameter. At lower flow rates, the amount of expansion was reduced, which suggests that lowering the flow rate may allow for improvements in sampling spatial resolution.

Plasma-based ambient mass spectrometry techniques: The current status and future prospective

Plasma-based ambient mass spectrometry is emerging as a frontier technology for direct analysis of sample that employs low-energy plasma as the ionization reagent. The versatile sources of ambient mass spectrometry (MS) can be classified according to the plasma formation approaches; namely, corona discharge, glow discharge, dielectric barrier discharge, and microwave-induced discharge. These techniques allow pretreatment-free detection of samples, ranging from biological materials (e.g., flies, bacteria, plants, tissues, peptides, metabolites, and lipids) to pharmaceuticals, food-stuffs, polymers, chemical warfare reagents, and daily-use chemicals. In most cases, plasma-based ambient MS performs well as a qualitative tool and as an analyzer for semi-quantitation. Herein, we provide an overview of the key concepts, mechanisms, and applications of plasma-based ambient MS techniques, and discuss the challenges and outlook.

Microwave induced plasma desorption ionization (MIPDI) mass spectrometry for qualitative and quantitative analysis of preservatives in cosmetics

The quantitative and qualitative behaviors of the MIPDI source were systematically studied for the first time in this work.

Paper-based analytical device with colorimetric assay application to the determination of phenolic acids and recognition of Fe3+

A paper-based analytical device is described for colorimetric detection of phenolic acids and recognition of Fe³⁺.

Emerging capabilities of mass spectrometry for natural products

Covering up to the end of 2013 A brief history of mass spectrometry in natural products research serves to identify themes which have driven progress in this area of application and in mass spectrometry itself. This account covers six decades of ionization methods, starting with traditional electron ionization and progressing through today's ambient ionization methods. Corresponding developments in mass analyzers are indicated, ranging from sector magnetic fields, through hybrid quadrupole mass filters to miniature ion traps. Current capabilities of mass spectrometry in natural products studies include direct in situ analysis, mass spectrometry imaging, and the study of biosynthetic pathways using metabolomic information. The survey concludes with a discussion of new experiments and capabilities including ion soft landing, preparative mass spectrometry, and accelerated ionic reactions in confined volumes.

Document authentication at molecular levels using desorption atmospheric pressure chemical ionization mass spectrometry imaging

Molecular images of documents were obtained by sequentially scanning the surface of the document using desorption atmospheric pressure chemical ionization mass spectrometry (DAPCI-MS), which was operated in either a gasless, solvent-free or methanol vapor-assisted mode. The decay process of the ink used for handwriting was monitored by following the signal intensities recorded by DAPCI-MS. Handwritings made using four types of inks on four kinds of paper surfaces were tested. By studying the dynamic decay of the inks, DAPCI-MS imaging differentiated a 10-min old from two 4 h old samples. Non-destructive forensic analysis of forged signatures either handwritten or computer-assisted was achieved according to the difference of the contour in DAPCI images, which was attributed to the strength personalized by different writers. Distinction of the order of writing/stamping on documents and detection of illegal printings were accomplished with a spatial resolution of about 140 µm. A Matlab® written program was developed to facilitate the visualization of the similarity between signature images obtained by DAPCI-MS. The experimental results show that DAPCI-MS imaging provides rich information at the molecular level and thus can be used for the reliable document analysis in forensic applications.

Phenolic composition analysis and gene expression in developing seeds of yellow- and black-seeded Brassica napus

Breeders have focused on yellow-seeded Brassica napus (rapeseed) for its better quality compared with the black-seeded variety. Moreover, flavonoids have been associated with this kind of rapeseed. In this study, we applied lipid chromatography-electrospray ionization mass spectrometry (LC-ESI-MS(n)) to compare flavonoids in developing seeds of natural black-seeded B. napus and yellow-seeded introgression lines selected from progenies of B. napus-Sinapis alba somatic hybrids. Aside from the most abundant phenolic compounds (sinapine and sinapic acid) and 1, 2-disinapoylglucose, 16 different flavonoids were identified and quantified, including (-)-epicatechin, five monocharged oligomers of (-)-epicatechin ([DP 2](-), [DP 3](-), [DP 4] [DP 2](-) B2 and [DP 2](-) B5), quercetin, kaempferol, isorhamnetin-dihexoside, kaempferol-sinapoyl-trihexoside, isorhamnetin-sinapoyl-trihexoside, isorhamnetin-hexoside-sulfate, and isorhamnetin-3-O-glucoside. Most of the flavonoids accumulated with seed development, whereas some rapidly decreased during maturation. The content of these flavonoids were lower in the yellow-seeded materials than in the black seeds. In addition, variations of insoluble procyanidin oligomers and soluble phenolic acids were observed among both rapeseed varieties. Transcriptome changes of genes participating in the flavonoid pathway were discovered by quantitative reverse transcription polymerase chain reaction analysis. Consistent with flavonoid changes identified by high performance liquid chromatography analysis, the expression of most genes in the flavonoid biosynthetic pathway was also downregulated.

Differential analysis of camphor wood products by desorption atmospheric pressure chemical ionization mass spectrometry

In the course of this study, desorption atmospheric pressure chemical ionization mass spectrometry (DAPCI-MS) was applied to readily acquire the mass spectral fingerprints of camphor wood and other wood samples under ambient conditions. Characteristic natural analytes, such as camphor and geraniol, were successfully detected in their protonated form and then identified by tandem mass spectrometry (MS(n)). Further principal component analysis (PCA) and cluster analysis (CA) of the mass spectrometric results allow a confident discrimination of camphor wood products from inferior/fake ones. These experimental findings demonstrate that DAPCI-MS is a valuable tool for differential analysis of untreated camphor wood products with sufficient sensitivity and high throughput.