Identification of new trace triterpenoid saponins from the roots of Panax notoginseng by high-performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry

Study of novel ginsenoside metabolites targeting HSP70 as anti-prostate cancer drugs

Ginsenoside 20 (R)-25-methoxy-dammarane-3 β, twelve β, 20 triol (AD-1) is a promising new drug for the treatment of prostate cancer, but its bioavailability is low. This study investigated the effects of the main metabolites PD and M6 of AD-1 on prostate cancer cell PC3. The in vitro experimental results showed that the IC50 values of PC3 cells treated with PD and M6 were 65.61 and 11.72, respectively. Both PD and M6 inhibited the migration of PC3 cells, and the cell cycle was blocked in the G1 phase. The apoptosis rates of cells following M6 treatment at concentrations of 7.5, 15, and 30 μM were 13.4 %, 17.5 %, and 41.4 %, respectively, which stimulated the expression of apoptosis protein and significantly increased intracellular ROS levels. In xenograft models, PD and M6 have been reported to significantly inhibit tumor growth. We used a genome-wide mRNA expression profile to study the effects of PD and M6 on gene expression in PC3 cancer cells. PD and M6 induced downregulation of HSP70 subtypes HSPA1A and HSPA1B. RT-PCR confirmed that the significant down-regulation of HSP70 subtype expressions was consistent with the results of Transcriptome analysis. Moreover, M6 significantly downregulated the expression of AR, which was further proved by Western blot analysis. In summary, our research findings provide a scientific basis for interpreting the significant activity of AD-1 in prostate cancer, and for the research and development of PD and M6 as novel HSP70 inhibitors.

Panaxadiol as a major metabolite of AD-1 can significantly inhibit the proliferation and migration of breast cancer cells: In vitro and in vivo study

Previous studies have shown that 20 (R)-25-methoxyl-dammarane-3β, 12β, 20 triol (AD-1) can inhibit various cancer cell lines. This study aimed to explore the effect and mechanism of AD-1 metabolite M2 (Panaxadiol; PD) on breast cancer cells of nude mice. Five AD-1 metabolites were isolated and identified using various chromatographic techniques. PD was the main component. In vitro results showed that PD could inhibit the proliferation and migration of MDA-MB-231 cells by inducing G1-phase arrest. In addition, PD down-regulated the expression of Cyclin D1, cdk2, cdk4, cdk6, P-p38, and MMP9, and up-regulated p21 and p27. In vivo results showed that PD could effectively reduce the volume, weight, and migration of breast cancer Transcriptomics analyzed 491 differentially expressed genes by GO and KEGG enrichment. RT-PCR verification confirmed that the significant down-regulation of MMP9 was consistent with transcriptomics results. In further research showed that PD regulated the protein expression of P-p38 and MMP9 in MAPK pathway. In summary, in vivo and in vitro studies showed that PD significantly inhibit the occurrence and development of breast cancer, possibly through the MAPK pathway.

Integrative omic and transgenic analyses reveal the positive effect of ultraviolet-B irradiation on salvianolic acid biosynthesis through upregulation of SmNAC1

Salvianolic acids (SalAs), a group of secondary metabolites in Salvia miltiorrhiza, are widely used for treating cerebrovascular diseases. Their biosynthesis is modulated by a variety of abiotic factors, including ultraviolet-B (UV-B) irradiation; however, the underlying mechanisms remain largely unknown. Here, an integrated metabolomic, proteomic, and transcriptomic approach coupled with transgenic analyses was employed to dissect the mechanisms underlying UV-B irradiation-induced SalA biosynthesis. Results of metabolomics showed that 28 metabolites, including 12 SalAs, were elevated in leaves of UV-B-treated S. miltiorrhiza. Meanwhile, the contents of several phytohormones, including jasmonic acid and salicylic acid, which positively modulate the biosynthesis of SalAs, also increased in UV-B-treated S. miltiorrhiza. Consistently, 20 core biosynthetic enzymes and numerous transcription factors that are involved in SalA biosynthesis were elevated in treated samples as indicated by a comprehensive proteomic analysis. Correlation and gene expression analyses demonstrated that the NAC1 gene, encoding a NAC transcriptional factor, was positively involved in UV-B-induced SalA biosynthesis. Accordingly, overexpression and RNA interference of NAC1 increased and decreased SalA contents, respectively, through regulation of key biosynthetic enzymes. Furthermore, ChIP-qPCR and Dual-LUC assays showed that NAC1 could directly bind to the CATGTG and CATGTC motifs present in the promoters of the SalA biosynthesis-related genes PAL3 and TAT3, respectively, and activate their expression. Our results collectively demonstrate that NAC1 plays a crucial role in UV-B irradiation-induced SalA biosynthesis. Taken together, our findings provide mechanistic insights into the UV-B-induced SalA biosynthesis in S. miltiorrhiza, and shed light on a great potential for the development of SalA-abundant varieties through genetic engineering.

Antithrombotic effect and action mechanism of Salvia miltiorrhiza and Panax notoginseng herbal pair on the zebrafish

Background

Salvia miltiorrhiza (Danshen, DS) and Panax notoginseng (Sanqi, SQ) are famous traditional Chinese herbs, and their herbal pair (DS–SQ) has been popular used as anti-thrombotic medicines. However, there is still a lack of sufficient scientific evidence to illustrate the optimum combination ratio of these two herbs as well as its action mechanisms. The purpose of this study is to investigate the anti-thrombotic effects of DS–SQ on zebrafish and explore its possible action mechanism.

Methods

Firstly, the chemical components in DS–SQ extract were analyzed by LC–ESI–MS/MS. Then, a phenylhydrazine (PHZ)-induced zebrafish thrombosis model was developed for evaluating the anti-thrombotic effects of DS–SQ extracts with different combination ratios and their nine pure compounds. Followed, Real-time quantitative PCR (RT-qPCR) assays were performed to investigate the potential antithrombotic mechanisms of DS–SQ.

Results

Thirty-three components were tentatively identified by LC–MS analysis. DS–SQ at the ratio of 10:1 presented the best anti-thrombotic effect, and rosmarinic acid, lithospermic acid and salvianolic acid B of DS showed good anti-thrombotic activity on zebrafish thrombosis model. The RT-qPCR assays indicated that DS–SQ (10:1) could cure the PHZ-induced thrombosis by downregulating the expression of PKCα, PKCβ, fga, fgb, fgg and vWF in zebrafish.

Conclusions

DS–SQ with the combination ratio of 10:1 showed optimum anti-thrombotic effect on PHZ-induced zebrafish thrombosis model, which provided a reference for reasonable clinical applications of DS–SQ herbal pair.

Phytochemical analysis of Panax species: a review

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

New perspective on the metabolism of AD-1 in vivo: Characterization of a series of dammarane-type derivatives with novel metabolic sites and anticancer mechanisms of active oleanane-type metabolites

20(R)-25-methoxyl-dammarane-3β,12β,20-triol (AD-1, CN Patent: 201010107476.7) is a novel derivative of dammarane-type ginsenoside. AD-1 has been shown to inhibit cancer cell proliferation without significant host toxicity in vivo, and has excellent development potential as a new anti-cancer agent. This study was designed systematically to explore the metabolic pathway of ginseng sapogenins. The metabolism of drugs in the body is a complex biotransformation process where drugs are structurally modified to different molecules (metabolites) through various metabolizing enzymes. The compounds responsible for the effects of orally administered ginseng are believed to be metabolites produced in the gastrointestinal tract, so understanding the metabolism of the drug candidate can help to optimize its pharmacokinetics. In this study, faeces samples were collected and extracted after oral administration of AD-1. The 16 metabolites of AD-1 were isolated and identified for the first time with various chromatographic techniques, including semi-preparative high performance liquid chromatography, nuclear magnetic resonance spectroscopy, and mass spectrometry; of these 16 metabolites, 10 were novel compounds. We first discovered the biotransformation of dammarane-type sapogenins into oleanane-type sapogenins in rats and found a series of metabolites that changed, mainly at C-25 and C-29. This study provides new ideas for the metabolic pathway of ginseng sapogenins. The isolated compounds were screened for their effect on the viability and proliferation against cancer cell lines (Human A549, MCF-7, HELA, HO-8901 and U87). The discovery of novel active metabolites 3β,12β,21α,22β-Hydroxy-24-norolean-12-ene (M6) may lead to a new or improved drug candidate. For one, M6 could inhibit the growth of all the tested cancer cells. Among the tested cell lines, M6 exhibited the most remarkable inhibitory effect on ovarian cancer HO-8901 cells, with IC50 value of 2.086 μM. On this basis, we studied the anticancer mechanisms of M6. The results indicated that the pro-apoptotic feature of M6 acts via a mitochondrial pathway. Our results indicated that M6 exhibited a higher inhibitory effect on cancer-cell proliferation than AD-1 by inducing cell apoptosis. Our work provides data for future investigations on the metabolic mechanism of AD-1 in vivo and the potential for future research on developing a new drug.

Metabolomics data fusion between near infrared spectroscopy and high-resolution mass spectrometry: A synergetic approach to boost performance or induce confusion

In general, data fusion can improve the classification performance of the model, but little attention is paid to the influence of the data fusion on the spatial distribution of the modeling samples. In this paper, the effect of data fusion on sample spatial distribution was studied through integrating NIR data and UHPLC-HRMS data for sulfur-fumigated Chinese herb medicine. Twelve samples collected from four different geographical origins were sulfur fumigated in the lab, and then metabolomics analysis was conducted using NIR and UHPLC-LTQ-Orbitrap mass spectrometer. First of all, the discriminating power of each technique was respectively examined based on PCA analysis. Secondly, combining NIR and UHPLC-HRMS data sets together with or without variable selection was parallelly compared. The results demonstrated that the discriminable ability was remarkably improved after data fusion, indicating data fusion could visualize variable selection and enhance group separation. Samples in the margin between two classes of samples may increase the experience error but has positive effect on the separation direction. Besides, an interesting feature extraction could obtain better discriminable effect than common data fusion. This study firstly provided a new path to employ a comprehensive analytical approach for discriminating SF Chinese herb medicines to simultaneously benefit from the advantages of several technologies.

A Bioactive Chemical Markers Based Strategy for Quality Assessment of Botanical Drugs: Xuesaitong Injection as a Case Study

Current chemical markers based quality assessment methods largely fail to reflect intrinsic chemical complexity and multiple mechanisms of action of botanical drugs (BD). The development of novel quality markers is greatly needed. Here we propose bioactive chemical markers (BCM), defined as a group of chemo-markers that exhibit similar pharmacological activities comparable to the whole BD, which can therefore be used to effectively assess the quality of BD. As a proof-of-concept, a BCM-based strategy was developed and applied to Xuesaitong Injection (XST) for assessing the efficacy and consistency of different batches. Firstly, systemic characterization of chemical profile of XST revealed a total number of 97 compounds. Secondly, notoginsenoside R₁, ginsenoside Rg₁, Re, Rb₁ and Rd were identified as BCM of XST on treating cardiovascular and cerebrovascular diseases according to Adjusted Efficacy Score following an in vivo validation. Analytical method for quantification of BCM was then developed to ensure the efficacy of XST. Finally, chemical fingerprinting was developed and used to evaluate the batch-to-batch consistency. Our present case study on XST demonstrates that BCM-based strategy offers a rational approach for quality assessment of BD and provides a workflow for chemistry, manufacturing, and controls (CMC) study of BD required by regulatory authority.

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

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

Analysis of the Constituents in "Zhu She Yong Xue Shuan Tong" by Ultra High Performance Liquid Chromatography with Quadrupole Time-of-Flight Mass Spectrometry Combined with Preparative High Performance Liquid Chromatography

“Zhu She Yong Xue Shuan Tong” lyophilized powder (ZSYXST), consists of a series of saponins extracted from Panax notoginseng, which has been widely used in China for the treatment of strokes. In this study, an ultra-high performance liquid chromatography with quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF/MS) combined with preparative high performance liquid chromatography (PHPLC) method was developed to rapidly identify both major and minor saponins in ZSYXST. Some high content components were removed through PHPLC in order to increase the sensitivity of the trace saponins. Then, specific characteristic fragment ions in both positive and negative mode were utilized to determine the types of aglycone, saccharide, as well as the saccharide chain linkages. As a result, 94 saponins, including 20 pairs of isomers and ten new compounds, which could represent higher than 98% components in ZSYXST, were identified or tentatively identified in commercial ZSYXST samples.

An integrated high resolution mass spectrometric data acquisition method for rapid screening of saponins in Panax notoginseng (Sanqi)

The aim of this study was to develop a convenient method without pretreatments for nontarget discovery of interested compounds. The segment and exposure strategy, coupled with two mass spectrometer data acquisition methods was firstly proposed for screening the saponins in extract of Panax notoginseng (Sanqi) via high-performance liquid chromatography tandem quadrupole time-of-flight mass spectrometry (HPLC-QTOF/MS). By gradually removing certain major or moderate interference compounds, the developed segment and exposure strategy could significantly improve the detection efficiency for trace compounds. Moreover, the newly developed five-point screening approach based on a modified mass defect filter strategy and the visual isotopic ion technique was verified to be efficient and reliable in picking out the interested precursor ions. In total, 234 ginsenosides including 67 potential new ones were characterized or tentatively identified from the extract of Sanqi. Particularly, some unusual compounds containing the branched glycosyl group or new substituted acyl groups were firstly reported. The proposed integrated strategy held a strong promise for analyses of the complex mixtures.

Determination of the triterpene glycosides in sea cucumbers by liquid chromatography with evaporative light scattering and mass spectrometry detection

Holothurian triterpene glycosides possess various kinds of biological activities, including antifungal, cytotoxic, hemolytic, cytostatic, and immunomodulatory effects. In this study, a rapid extraction method of triterpene glycosides from sea cucumbers using a small column of C18 solid phase was first developed. Furthermore, a novel high-performance liquid chromatography method coupled with evaporative light scattering detection and electrospray ionization mass spectrometry was established for the determination of each triterpene glycosides from different sea cucumbers. Simultaneous separation of all kind of triterpene glycoside were achieved on a C18 column. A gradient of aqueous acetonitrile was applied, and the method was validated. The liquid chromatography method was applied to the online mass detection to identify the triterpene glycosides in the purified extraction of eight kinds of pulverized sea cucumber from the market of Qingdao, China. The negative mode of [M-H](-)/[M-Na](-) exclusively shown signals corresponding to the triterpene glycosides previously reported and the MS(2) product ions of those ions indicate the specific structure of each triterpene glycoside.

Saponins in the genus Panax L. (Araliaceae): a systematic review of their chemical diversity

The Panax genus is a crucial source of natural medicines that has benefited human health for a long time. Three valuable medicinal herbs, namely Panax ginseng, Panax quinquefolius, and Panax notoginseng, have received considerable interest due to their extensive application in clinical therapy, healthcare products, and as foods and food additives world-wide. Panax species are known to contain abundant levels of saponins, also dubbed ginsenosides, which refer to a series of dammarane or oleanane type triterpenoid glycosides. These saponins exhibit modulatory effects to the central nervous system and beneficial effects to patients suffering from cardiovascular diseases, and also have anti-diabetic and anti-tumor properties. To the end of 2012, at least 289 saponins were reported from eleven different Panax species. This comprehensive review describes the advances in the phytochemistry of the genus Panax for the period 1963-2012, based on the 134 cited references. The reported saponins can be classified into protopanaxadiol, protopanaxatriol, octillol, oleanolic acid, C17 side-chain varied, and miscellaneous subtypes, according to structural differences in sapogenins. The investigational history of Panax is also reviewed, with special attention being paid to the structural features of the six different subtypes, together with their (1)H and (13)C NMR spectroscopic characteristics which are useful for determining their structures and absolute configuration.

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.

Discrimination of white ginseng origins using multivariate statistical analysis of data sets

Background

White ginseng (Panax ginseng Meyer) is commonly distributed as a health food in food markets. However, there is no practical method for distinguishing Korean white ginseng (KWG) from Chinese white ginseng (CWG), except for relying on the traceability system in the market.

Methods

Ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry combined with orthogonal partial least squares discrimination analysis (OPLS-DA) was employed to discriminate between KWG and CWG.

Results

The origins of white ginsengs in two test sets (1.0 μL and 0.2 μL injections) could be successfully discriminated by the OPLS-DA analysis. From OPLS-DA S-plots, KWG exhibited tentative markers derived from ginsenoside Rf and notoginsenoside R3 isomer, whereas CWG exhibited tentative markers derived from ginsenoside Ro and chikusetsusaponin Iva.

Conclusion

Results suggest that ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry coupled with OPLS-DA is an efficient tool for identifying the difference between the geographical origins of white ginsengs.

Determination of platycodin D and platycodin D3 in rat plasma using liquid chromatography-tandem mass spectrometry

Platycodon grandiflorum has long been used as a traditional oriental medicine for respiratory disorder. Platycodin D (PD) is known as the main component isolated from the root of PG. A simple and rapid liquid chromatography-tandem mass spectrometry (LC-MS/MS) method has been developed and validated for the quantitation of PD in rat plasma. Quantitation was performed on a triple quadrupole mass spectrometer employing electrospray ionization and multiple reaction monitoring in positive ion mode. The total chromatographic run time was 4.0 min, and the calibration curves of PD were linear over the concentration range of 50-10,000 ng/mL in rat plasma. The coefficient of variation and relative error at five QC levels were 1.0 to 8.8% and 0.7 to 8.7%, respectively. After a single oral administration of 500 mg/kg and a single intravenous administration of 25 mg/kg of 3% PD extract (a PG extract including 3% of PD), platycodin D and platycodin D3 were detected and pharmacokinetic parameters were estimated. The oral bioavailability of platycodin D and platycodin D3 was 0.29% and 1.35% in rats at 500 mg/kg of 3% PD extract of PG, respectively. The present method can be applied to pharmacokinetic analysis of platycodins and platycosides of the PG.

Recent methodology in ginseng analysis

As much as the popularity of ginseng in herbal prescriptions or remedies, ginseng has become the focus of research in many scientific fields. Analytical methodologies for ginseng, referred to as ginseng analysis hereafter, have been developed for bioactive component discovery, phytochemical profiling, quality control, and pharmacokinetic studies. This review summarizes the most recent advances in ginseng analysis in the past half-decade including emerging techniques and analytical trends. Ginseng analysis includes all of the leading analytical tools and serves as a representative model for the analytical research of herbal medicines.

Chemical Diversity of Panax ginseng, Panax quinquifolium, and Panax notoginseng

The major commercial ginsengs are Panax ginseng Meyer (Korean ginseng), P. quinquifolium L. (American ginseng), and P. notoginseng (Burk.) FH Chen (Notoginseng). P. ginseng is the most commonly used as an adaptogenic agent and has been shown to enhance physical performance, promote vitality, increase resistance to stress and aging, and have immunomodulatory activity. These ginsengs contain saponins, which can be classified as dammarane-type, ocotillol-type and oleanane-type oligoglycosides, and polysaccharides as main constituents. Dammarane ginsenosides are transformed into compounds such as the ginsenosides Rg3, Rg5, and Rk1 by steaming and heating and are metabolized into metabolites such as compound K, ginsenoside Rh1, protoand panaxatriol by intestinal microflora. These metabolites are nonpolar, pharmacologically active and easily absorbed from the gastrointestinal tract. However, the activities metabolizing these constituents into bioactive compounds differ significantly among individuals because all individuals possess characteristic indigenous strains of intestinal bacteria. To overcome this difference, ginsengs fermented with enzymes or microbes have been developed.

Nontargeted metabolomics approach for age differentiation and structure interpretation of age-dependent key constituents in hairy roots of Panax ginseng

The age of the ginseng plant has been considered as an important criterion to determine the quality of this species. For age differentiation and structure interpretation of age-dependent key constituents of Panax ginseng, hairy root (fine root) extracts aged from four to six years were analyzed using a nontargeted approach with ultraperformance liquid chromatography/quadrupole time-of-flight mass spectrometry (UPLC-QTOFMS). Various classification methods were used to determine an optimal method to best describe ginseng age by selecting influential metabolites of different ages. Through the metabolite selection process, several age-dependent key constituents having the potential to be biomarkers were determined, and their structures were identified according to tandem mass spectrometry and accurate mass spectrometry by comparing them with an in-house ginsenoside library and with literature data. This proposed method applied to the hairy roots of P. ginseng showed an improved efficiency of age differentiation when compared to previous results on the main roots and increases the possibility of the identification of key metabolites that can be used as biomarker candidates for quality assurance in ginseng.

A strategy for efficient discovery of new natural compounds by integrating orthogonal column chromatography and liquid chromatography/mass spectrometry analysis: Its application in Panax ginseng, Panax quinquefolium and Panax notoginseng to characterize 437 potential new ginsenosides

To discover new natural compounds from herbal medicines tends to be more and more difficult. In this paper, a strategy integrating orthogonal column chromatography and liquid chromatography/mass spectrometry (LC/MS) analysis was proposed, and was applied for rapid discovery of new ginsenosides from Panax ginseng (PG), Panax quinquefolium (PQ), and Panax notoginseng (PN). The ginsenosides extracts were fractionated by MCI gel×silica gel orthogonal column chromatography. The fractions were then separated on a C(18) HPLC column, eluted with a three-component mobile phase (CH(3)CN/CH(3)OH/3mM CH(3)COONH(4)H(2)O), and detected by electrospray ionization tandem mass spectrometry. The structures of unknown ginsenosides were elucidated by analyzing negative and positive ion mass spectra, which provided complementary information on the sapogenins and oligosaccharide chains, respectively. A total of 623 comprising 437 potential new ginsenosides were characterized from the ethanol extracts of PG, PQ and PN. New acylations, diversified saccharide chains and C-17 side chains constituted novelty of the newly identified ginsenosides. An interpretation guideline was proposed for structural characterization of unknown ginsenosides by LC/MS. To confirm reliability of this strategy, two targeted unknown trace ginsenosides were obtained in pure form by LC/MS-guided isolation. Based on extensive NMR spectroscopic analysis and other techniques, they were identified as 3-O-[6-O-(E)-butenoyl-β-D-glucopyranosyl(1,2)-β-D-glucopyranosyl]-20(S)-protopanaxadiol-20-O-β-D-glucopyranosyl(1,6)-β-D-glucopyranoside (named ginsenoside IV) and 3-O-β-D-glucopyranosyl(1,2)-β-D-glucopyranosyl-3β,12β,20(S),24(R)-tetra hydroxy-dammar-25-ene-20-O-β-D-glucopyranosyl(1,6)-β-D-glucopyranoside (ginsenoside V), respectively. The fully established structures were consistent with the MS-oriented structural elucidation. This study expanded our understanding on ginsenosides of Panax species, and the proposed strategy was proved efficient and reliable in the discovery of new minor compounds from herbal extracts.

Target separation of a new anti-tumor saponin and metabolic profiling of leaves of Panax notoginseng by liquid chromatography with eletrospray ionization quadrupole time-of-flight mass spectrometry

A method coupling high-performance liquid chromatography (HPLC) with quadrupole time-of-flight mass spectrometers (QTOF-MS) using an eletrospray ionization (ESI) source was firstly developed for detection, characterization and guiding target separation of variants of protopanaxdiol saponin from leaves of Panax notoginseng. Under the guidance of LC-QTOF-MS, a new trace saponin was probed according to the precise elemental compositions of molecular ions and the fragmentation behavior, and then separated from the ethanol extract of the plant by a set of chromatographic methods. It was further confirmed by NMR experiments as 3-O-β-D-glucopyranoside-3β,l2β,23β-triol-20-ene-dammar (Pn-1). The cytotoxic assay showed that Pn-1 had relatively stronger anti-tumor effects against three tumor cell lines (NCI-H460, HepG2 and SGC-7901) than Rg₃, an approved clinical agent for cancer therapy. Meanwhile, based on accurate mass measurements within 5 ppm for each molecular ions and subsequent product ions, 48 saponins, including 40 protopanaxadiol saponins, 7 protopanaxatriol saponins and 1 oleanane saponin were identified. It is noted that the knowledge of the presence of abundant protopanaxadiol saponins in leaves of P. notoginseng may provide tools for a full understanding of the chemical diversity of secondary metabolites from the different parts of P. notoginseng. From the points of time consuming and accurate mass measurement capability, the LC-QTOF-MS is a highly powerful tool for screening and guiding target separation of new compounds in herbal extract, and thus benefits the speed of new drug discovery progress.

Structure characterization and identification steroidal saponins from Ophiopogon japonicus Ker-Gawler (Liliaceae) by high-performance liquid chromatography with ion trap mass spectrometry

INTRODUCTION

Steroidal saponins are the main active constituents in Ophiopogon japonicus Ker-Gawler (Liliaceae). However, because of their high polarity, non-chromophores and low content in plants, steroidal saponins are difficult to be isolated from O. japonicus by conventional phytochemical methods.

OBJECTIVE

To develop a sensitive and rapid approach towards the structural analysis of steroidal saponins using HPLC/ESI-MS(n).

METHODOLOGY

The fragmentation behaviors of six known steroidal saponins in negative ESI-MS(n) were used to deduce their mass spectral fragmentation mechanisms. By using HPLC/ESI-MS(n) , the important structural information on aglycone types, sugar types and saccharide sequences can be obtained.

RESULTS

According to the HPLC retention behaviour, the molecular structural characteristics provided by multistage mass spectrometry spectra and the literature, a total of 8 steroidal saponins were tentatively identified or characterized in O. japonicus rapidly.

CONCLUSION

This work has shown that HPLC-ESI-MS(n) may be used as an effective and rapid method for the characterization and identification of steroidal saponins from O. japonicus.

Isolation and analysis of ginseng: advances and challenges

Ginseng occupies a prominent position in the list of best-selling natural products in the world. Because of its complex constituents, multidisciplinary techniques are needed to validate the analytical methods that support ginseng's use worldwide. In the past decade, rapid development of technology has advanced many aspects of ginseng research. The aim of this review is to illustrate the recent advances in the isolation and analysis of ginseng, and to highlight new applications and challenges. Emphasis is placed on recent trends and emerging techniques.

Rapid separation and identification of major constituents in Pseudolarix kaempferi by ultra-performance liquid chromatography coupled with electrospray and quadrupole time-of-flight tandem mass spectrometry

A rapid and reliable method based on ultra-performance liquid chromatography (UPLC) coupled with photodiode-array detection (PDA) and electrospray ionization quadrupole time-of-flight tandem mass spectrometry (ESI-Q-TOF-MS/MS) has been developed for separation and identification of major constituents in extracts of root bark of Pseudolarix kaempferi Gordon (PKG). Identification of the constituents was carried out by interpretation of their retention times, UV absorption spectra, MS and MS/MS spectra, as well as the data provided by authentic standards and literatures. A total of 20 components were separated in only 8.0 min on a small particle size C18 column (1.7 microm). These components included nine diterpene acids, seven glycosides and four triterpenoids, among which pseudolaric acid C-O-beta-D-glucopyranoside and pseudolaric acid C2-O-beta-D-glucopyranoside were separated and identified for the first time in this study. Furthermore, the fragmentation patterns of the three types of compounds were elucidated for the first time. This established UPLC-PDA/Q-TOF-MS/MS method is reliable and effective for the separation and identification of the 20 compounds and will be useful for quality control of the crude materials of Pseudolarix kaempferi Gordon and their related preparations.

Rapid differentiation of isobaric and positional isomers of structurally related glycosides from Phytolacca bogotensis

Through the action of glycosyltransferases, a plant can biosynthetically assemble small different aglycons or 'templates' to various polysaccharides to produce numerous glycoconjugates differing in the type of the attached aglycon, the anomeric configuration of C-1 of the glycosylating sugar, the type of sugar and the different position of attachments of the sugar unit present in the polysaccharide chain. The position of attachments and the anomeric configuration of the different sugar present in the polysaccharide create the opportunity to generate molecules with either the same or very close molecular weights, which have relative structural similarity--forming isobaric and positional isomers. Although isomeric differentiation was once considered outside of the domain of mass spectrometry, this task can now be resolved using tandem mass spectrometry. In a standardized purified glycoconjugate fraction (SPT01) from Phytolacca bogotensis, we report conventional electrospray ionization mass spectrometry and collision-induced dissociation (CID) MS/MS parameters which favored the formation of characteristic product ions. This allowed us to suggest the type of sugar linkages present in a specific glycoconjugate. Ten new glycoconjugate are described from this plant and another twelve known saponins were structurally characterized using the automatic MSn acquisition mode. The differentiation of two pairs of positional isomers and four isobaric glycosides and the production of a library of 30 glycosides present in P. bogotensis were accomplished.