Jianqiu Lu

Rapid screening and identification of target constituents using full scan-parent ions list-dynamic exclusion acquisition coupled to diagnostic product ions analysis on a hybrid LTQ-Orbitrap mass spectrometer

A highly sensitive and effective strategy for rapid screening and identification of target constituents has been developed using full scan-parent ions list-dynamic exclusion (FS-PIL-DE) acquisition coupled to diagnostic product ions (DPIs) analysis on a hybrid LTQ-Orbitrap mass spectrometer. The FS-PIL-DE was adopted as a survey scan to trigger the MS/MS acquisition of all the predictable constituents contained in traditional Chinese medicines. Additionally, DPIs analysis can provide a criterion to judge the target constituents detected into certain chemical families. Results from analyzing polymethoxylated flavonoids (PMFs) in the leaves of Citrus reticulata Blanco demonstrated that FS-PIL-DE was capable of targeting a greater number of constituents than FS, FS-PIL and FS-DE, thereby increasing the coverage of constituent screening. As a result, 135 PMFs including 81 polymethoxyflavones, 54 polymethoxyflavanones or polymethoxychalcones were identified preliminarily. And this was the first time to systematically report the presence of PMFs in the leaves of Citrus reticulata Blanco, especially for polymethoxylated flavanones and chalcones, most of which were new compounds. The results indicated that the developed FS-PIL-DE coupled to DPIs analysis methodology could be employed as a rapid, effective technique to screen and identify target constituents from TCMs extracts and other organic matter mixtures whose compounds contained can also be classified into families based on the common carbon skeletons.

Profiling and identification of the metabolites of baicalin and study on their tissue distribution in rats by ultra-high-performance liquid chromatography with linear ion trap-Orbitrap mass spectrometer

Baicalin (baicalein 7-O-glucuronide), which is one of the major bioactive constituents isolated from Scutellariae Radix, possesses many biological activities, such as antiallergic, antioxidation, and anti-inflammatory activities. In the present study, an efficient strategy was established using ultra-high-performance liquid chromatography coupled with linear ion trap-Orbitrap mass spectrometer (UPLC-LTQ-Orbitrap MS) to profile the in vivo metabolic fate of baicalin in rat plasma, urine, and various tissues. A combination of post-acquisition mining methods including extracted ion chromatogram (EIC) and multiple mass defect filters (MMDF) was adopted to identify the common and uncommon baicalin metabolites from the full mass scan data sets. Their structures were elucidated based on the accurate mass measurement, relevant drug biotransformation knowledge, the characteristic collision induced fragmentation pattern of baicalin metabolites, and bibliography data. Based on the proposed strategy, a total of 32 metabolites were observed and characterized. The corresponding reactions in vivo such as methylation, hydrolysis, hydroxylation, methoxylation, glucuronide conjugation, sulfate conjugation, and their composite reactions, were all discovered in the study. The results demonstrated that the rat liver and kidney are the most important organs for the baicalin metabolites presence. Six metabolites might play an important role in exerting pharmacological effects of baicalin in vivo. The newly discovered baicalin metabolites significantly expanded our understanding on its pharmacological effects, and could be targets for future studies on the important chemical constituents from herbal medicines.

A strategy for comprehensive identification of sequential constituents using ultra-high-performance liquid chromatography coupled with linear ion trap–Orbitrap mass spectrometer, application study on chlorogenic acids in Flos Lonicerae Japonicae

The analytical methodologies for evaluation of multi-component system in traditional Chinese medicines (TCMs) have been inadequate or unacceptable. As a result, the unclarity of multi-component hinders the sufficient interpretation of their bioactivities. In this paper, an ultra-high-performance liquid chromatography coupled with linear ion trap-Orbitrap (UPLC-LTQ-Orbitrap)-based strategy focused on the comprehensive identification of TCM sequential constituents was developed. The strategy was characterized by molecular design, multiple ion monitoring (MIM), targeted database hits and mass spectral trees similarity filter (MTSF), and even more isomerism discrimination. It was successfully applied in the HRMS data-acquisition and processing of chlorogenic acids (CGAs) in Flos Lonicerae Japonicae (FLJ), and a total of 115 chromatographic peaks attributed to 18 categories were characterized, allowing a comprehensive revelation of CGAs in FLJ for the first time. This demonstrated that MIM based on molecular design could improve the efficiency to trigger MS/MS fragmentation reactions. Targeted database hits and MTSF searching greatly facilitated the processing of extremely large information data. Besides, the introduction of diagnostic product ions (DPIs) discrimination, ClogP analysis, and molecular simulation, raised the efficiency and accuracy to characterize sequential constituents especially position and geometric isomers. In conclusion, the results expanded our understanding on CGAs in FLJ, and the strategy could be exemplary for future research on the comprehensive identification of sequential constituents in TCMs. Meanwhile, it may propose a novel idea for analyzing sequential constituents, and is promising for quality control and evaluation of TCMs.

Rapid Identification of Polymethoxylated Flavonoids in Traditional Chinese Medicines with a Practical Strategy of Stepwise Mass Defect Filtering Coupled to Diagnostic Product Ions Analysis based on a Hybrid LTQ‐Orbitrap Mass Spectrometer

INTRODUCTION The methodology of stepwise mass defect filtering (MDF) approach coupled to diagnostic product ions (DPIs) analysis on a hybrid linear trap quadrupole (LTQ)/orbitrap mass spectrometer was the first to be established to screen and identify structural analogues from complex herbal extracts. OBJECTIVE To develop an analytical methodology that could be adopted to screen and identify structural analogues in traditional Chinese medicines (TCMs) rapidly and accurately. METHODS Taking polymethoxylated flavonoids (PMFs) in the leaves of Citrus reticulata Blanco as an example, high-resolution mass data were acquired by high-performance liquid chromatography (HPLC) coupled with a LTQ/orbitrap mass spectrometer. The stepwise MDF with multiple mass defect windows or mass windows enabled the original data to be analysed much faster and more accurately by reducing the potential interferences of matrix ions. Additionally, analysis of DPIs could provide a criterion to classify the target constituents detected into certain chemical families. RESULTS In total, 81 PMFs, including 50 polymethoxyflavones and 31 polymethoxyflavanones or polymethoxychalcones, were screened and identified from the original data and preliminarily identified. CONCLUSION The analytical methodology developed could be used as a rapid, effective technique to screen and identify compounds from TCM extracts and other organic matter mixtures with compounds that can also be classified into families based on the common carbon skeletons.

Identification of the metabolites of Ixerin Z from Ixeris sonchifolia Hance in rats by HPLC–LTQ-Orbitrap mass spectrometry

Ixerin Z, one of major sesquiterpene lactones from Ixeris sonchifolia Hance, was considered to be a major active compound because of their special structure and activity. However, studies on Ixerin Z metabolism have rarely been reported. This study is the first to investigate the in vivo metabolism of Ixerin Z following intravenously administered of Ixerin Z by HPLC-LTQ-Orbitrap mass spectrometry and multiple mass defect filters (MMDF) technique. A total of 41 metabolites as well as parent drug after using two MMDF filter templates were unambiguously or tentatively identified based on accurate mass measurements, fragmentation patterns, and chromatographic retention times. The metabolic pathways of Ixerin Z were also proposed for the first time. The results demonstrated that Ixerin Z underwent extensive metabolic reaction including hydrogenation, hydroxylation, hydrolysis, methylation, cysteine conjugation, glutathione (GSH) conjugation, sulfate conjugation, N-acetylcysteine conjugation, and glucuronidation. In conclusion, our study provided an insight into the metabolism of Ixerin Z.

Rapid identification of polyphenols in Kudiezi injection with a practical technique of mass defect filter based on high-performance liquid chromatography coupled with linear ion trap/orbitrap mass spectrometry

In the present study, a practical approach of mass defect filter (MDF), a data-mining technique, was developed and evaluated for the rapid classification of complicated peaks into well-known chemical families based on the exact mass acquired by high-resolution mass spectrometry. The full-scan mass data of Kudiezi injection was acquired by high-performance liquid chromatography coupled with a linear ion trap-orbitrap mass spectrometer system (HPLC-LTQ-Orbitrap) that features high resolution, mass accuracy and sensitivity. To screen the polyphenols including chlorogenic acids (CGAs) and flavonoids in the injection, the MDF approach was employed to rapidly screen them from the complex system. First, two filtering templates and several filters were set to remove the interference ions of a complex matrix by MetWorks 1.3 Software. Then, the filtered target peaks were characterized according to their accurate mass data and MSn fragment ions. Utilizing the proposed approach, 14 CGAs and 16 flavonoids could be screened and identified. The results of rapid screening and detection showed that the developed MDF approach based on high-resolution mass spectrometry would be adaptable to the analysis of a complex system of traditional Chinese medicines.

Profiling and identification of (-)-epicatechin metabolites in rats using ultra-high performance liquid chromatography coupled with linear trap-Orbitrap mass spectrometer.

(-)-Epicatechin (EC), an optical antipode of (+)-catechin (C), possesses many potential significant health benefits. However, the in vivo metabolic pathway of EC has not been clarified yet. In this study, an efficient strategy based on ultra-high performance liquid chromatography coupled with a linear ion trap-Orbitrap mass spectrometer was developed to profile and characterize EC metabolites in rat urine, faeces, plasma, and various tissues. Meanwhile, post-acquisition data-mining methods including high-resolution extracted ion chromatogram (HREIC), multiple mass defect filters (MMDFs), and diagnostic product ions (DPIs) were utilized to screen and identify EC metabolites from HR-ESI-MS1 to ESI-MSn stage. Finally, a total of 67 metabolites (including parent drug) were tentatively identified based on standard substances, chromatographic retention times, accurate mass measurement, and relevant drug biotransformation knowledge. The results demonstrated that EC underwent multiple in vivo metabolic reactions including methylation, dehydration, hydrogenation, glucosylation, sulfonation, glucuronidation, ring-cleavage, and their composite reactions. Among them, methylation, dehydration, glucosylation, and their composite reactions were observed only occurring on EC when compared with C. Meanwhile, the distribution of these detected metabolites in various tissues including heart, liver, spleen, lung, kidney, and brain were respectively studied. The results demonstrated that liver and kidney were the most important organs for EC and its metabolites elimination. In conclusion, the newly discovered EC metabolites significantly expanded the understanding on its pharmacological effects and built the foundation for further toxicity and safety studies. Copyright

HPLC-LTQ-orbitrap MSn profiling method to comprehensively characterize multiple chemical constituents in xiao-er-qing-jie granules

In the present study, a method based on high performance liquid chromatography coupled with linear ion trap-orbitrap mass spectrometry (HPLC-LTQ-orbitrap) was developed for a comprehensive study of the multiple chemical constituents in xiao-er-qing-jie (XEQJ) granules, which are regularly used as a traditional Chinese medicine (TCM) for the treatment of children with high fever, sore throat, and lusterless complexion. Seven major categories of constituents preliminarily isolated from the component herbs were rapidly characterized using HPLC-LTQ-orbitrap. The fragmentation patterns of these compounds with different skeletons were clearly elaborated in the electrospray ionization (ESI) collision induced dissociation (CID)-MS/MS experiments. Based on the accurate mass measurement (<5 ppm), MS/MS fragmentation patterns, diagnostic product ions, and different chromatographic behaviors, 91 compounds were unambiguously identified or tentatively characterized, including 33 phenylethanoid glycosides, 13 phenolic acids, 11 flavonoids, 10 alkaloids, 9 lignans, 9 iridoid glycosides, and 6 saponins. Among them, 2 compounds were potential new ones from Forsythiae Fructus and 24 were unambiguously confirmed by comparing with their respective reference standards. The results demonstrated that our established method was useful and efficient to screen and identify targeted constituents from TCM extracts and other organic matter mixtures whose constituent compounds can also be classified into families on the basis of common carbon skeletons.

Simultaneous screening and identifying four categories of particular flavonoids in the leaves of Murraya exotica L. by HPLC-DAD-ESI-MS-MS.

Polymethoxylated flavonoids (PMFs), the particular flavonoid subclass in which all or almost all hydroxyls are capped by methylation, have high oral bioavailability and various activities. A sensitive high-performance liquid chromatography-diode array detection-electrospray ionization tandem mass spectrometry (HPLC-DAD-ESI-MS-MS) method was established to screen and identify the PMFs in the leaves of Murraya exotica. Eight PMF standards, including two polymethoxylated flavones, two polymethoxylated flavanones, two polymethoxylated chalcones and two PMF glycosides, were first to be analyzed in positive mode by collision-induced dissociation MS-MS. On the basis of the ESI-MS, characterizations were deduced, and in the results of the extracted ion chromatogram MS-MS experiment, 26 PMFs, including 18 flavones, five flavanones or chalcones and three PMF glycosides, were screened out from the complex extract of the leaves of M. exotica. Among them, 24 PMFs were hydroxylated polymethoxyflavonoids, whereas the rest were all permethoxylated PMFs. This was the first systematic report on the presence of PMFs in the leaves of M. exotica. The results indicated that the established analytical method could be adopted as a rapid, effective technique for the structural characterization of PMFs from the complex extracts of traditional Chinese medicines.

Identification of Metabolites of 6'-Hydroxy-3,4,5,2',4'-pentamethoxychalcone in Rats by a Combination of Ultra-High-Performance Liquid Chromatography with Linear Ion Trap-Orbitrap Mass Spectrometry Based on Multiple Data Processing Techniques.

In this study, an efficient strategy was established using ultra-high-performance liquid chromatography coupled with linear ion trap-Orbitrap mass spectrometry (UHPLC-LTQ-Orbitrap MS) to profile the in vivo metabolic fate of 6′-hydroxy-3,4,5,2′,4′-pentamethoxychalcone (PTC) in rat urine and feces. The UHPLC-LTQ-Orbitrap method combines the high trapping capacity and MSn scanning function of the linear ion trap along with accurate mass measurements within 5 ppm and a resolving power of up to 30,000 over a wider dynamic range compared to many other mass spectrometers. In order to reduce the potential interferences of endogenous substances, the post-acquisition processing method including high-resolution extracted ion chromatogram (HREIC) and multiple mass defect filters (MMDF) were developed for metabolite detection. As a result, a total of 60 and 35 metabolites were detected in the urine and feces, respectively. The corresponding in vivo reactions such as methylation, hydroxylation, hydrogenation, decarbonylation, demethylation, dehydration, methylation, demethoxylation, sulfate conjugation, glucuronide conjugation, and their composite reactions were all detected in this study. The result on PTC metabolites significantly expanded the understanding of its pharmacological effects, and could be targets for future studies on the important chemical constituents from herbal medicines.