Structural analysis of platycosides in Platycodi Radix by liquid chromatography/electrospray ionization-tandem mass spectrometry

Chromosome-Scale Genome Assembly and Triterpenoid Saponin Biosynthesis in Korean Bellflower (Platycodon grandiflorum)

Platycodon grandiflorum belongs to the Campanulaceae family and is an important medicinal and food plant in East Asia. However, on the whole, the genome evolution of P. grandiflorum and the molecular basis of its major biochemical pathways are poorly understood. We reported a chromosome-scale genome assembly of P. grandiflorum based on a hybrid method using Oxford Nanopore Technologies, Illumina sequences, and high-throughput chromosome conformation capture (Hi-C) analysis. The assembled genome was finalized as 574 Mb, containing 41,355 protein-coding genes, and the genome completeness was assessed as 97.6% using a Benchmarking Universal Single-Copy Orthologs analysis. The P. grandiflorum genome comprises nine pseudo-chromosomes with 56.9% repeat sequences, and the transcriptome analysis revealed an expansion of the 14 beta-amylin genes related to triterpenoid saponin biosynthesis. Our findings provide an understanding of P. grandiflorum genome evolution and enable genomic-assisted breeding for the mass production of important components such as triterpenoid saponins.

Ultra-high-performance liquid chromatography quadrupole time-of-flight tandem mass spectrometry coupled with three-step data post-processing techniques for comprehensive profiling of the multiple components in Fufang Xianzhuli Ye

INTRODUCTION

Fufang Xianzhuli (FXZL) Ye, a classical formula of traditional Chinese medicine, is composed of Succus Bambusae, Houttuyniae herba, Pinelliae Rhizoma, Zingiberis Rhizoma Recens, Eriobotryae Folium, Platycodonis Radix, and peppermint oil. For many years, FXZL has been primarily utilised in China to treat cough and phlegm. The chemical composition of FXZL has not been reported, which seriously affects the safety of the clinical application.

OBJECTIVE

To establish a systematic method for rapidly classifying and recognising the chemical constituents in the FXZL for the safety of the clinical application.

METHODS

An ultra-high performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry coupled with a three-step data post-processing strategy was developed to screen the chemical constituents of FXZL.

RESULTS

In this experiment, the diagnostic ions in FXZL were classified into six main compounds. A total of 106 compounds were unambiguously identified in FXZL based on their retention times, accurate masses, and tandem mass spectrometry data. These include 11 chlorogenic acids, three flavonoids, eight sesquiterpenoids, six organic acids, 65 triterpenoid saponins, and 13 other compounds.

CONCLUSION

The chemical composition of FXZL was identified and summarised, providing useful information for quality control and a basis for further exploration of its active ingredients in vivo.

UPLC-ESI-MS/MS profiling of the underground parts of common Iris species in relation to their anti-virulence activities against Staphylococcusaureus

ETHNOPHARMACOLOGICAL RELEVANCE

The use of plant extracts and their phytochemicals as candidates for targeting the microbial resistance inhibition is increasingly focused in last decades. In Mongolian traditional medicine, Irises were long used for the treatment of bacterial infections. Irises have been used since the Ancient Egyptians.

AIM OF THE STUDY

Chemical composition and virulence inhibition potential of both polar (PF) and non-polar fractions (NPF) of three common Iris species (I. confusa, I. pseudacorus and I. germanica) were explored.

MATERIAL AND METHODS

Secondary metabolites profiling was characterized by the UPLC-HRMS/MS technique. Multi-variate data analysis was performed using Metaboanalyst 3.0. Anti-virulence inhibitory activity was evaluated via anti-haemolytic assay and Quantitative biofilm inhibition assay.

RESULTS

I. pseudacorus PF exhibited the most potent effect against S. aureus haemolytic activity. All the tested fractions from all species, except I. pseudacorus NPF, have no significant inhibition on the biofilm formation of methicillin resistant and sensitive (MRSA and MSSA) S. aureus. I. pseudacorus NPF showed potent biofilm inhibitory potential of 71.4 and 85.8% against biofilm formation of MRSA and MSSA, respectively. Metabolite profiling of the investigated species revealed ninety and forty-five metabolites detected in the PFs and NPFs, respectively. Nigricin-type, tectorigenin-type isoflavonids and xanthones allowed the discrimination of I. pseudacorus PF from the other species, highlighting the importance of those metabolites in exerting its promising activity. On the other hand, triterpene acids, iridals, triacylglycerols and ceramides represented the metabolites detected in highest abundance in I. pseudacorus NPF.

CONCLUSIONS

This is the sole map represents the secondary metabolites profiling of the PFs and NPFs of common Iris species correlating them with the potent explored Staphylococcus aureus anti-virulence activity.

Comprehensive characterization of the chemical constituents in Platycodon grandiflorum by an integrated liquid chromatography-mass spectrometry strategy

Platycodon grandiflorum (PG), as a well-known medicine food homology species, possess various pharmacological effects and health benefits. Aiming to facilitate in-depth and global characterization of the chemical compositions of PG, a profiling method based on ultra-high performance liquid chromatography coupled with ion mobility quadrupole time-of-flight mass spectrometry (UPLC/IM-QTOF-MS) was conducted. Consequently, as many as 187 compounds were plausibly or unambiguously identified. Most importantly, phospholipids (PLs) were first observed and identified in PG. Due to their widely confirmed bioactivities, an analysis scheme was developed by hydrophilic interaction liquid chromatography and electrospray ionization tandem mass spectrometry combined with the online Paternò-Büchi reaction (HILIC-PB-MS/MS). The fatty acyl chains and C=C locations of 180 PLs molecular species, which fell into four classes, were unprecedently characterized. This exposure strategy of multi-type constituents greatly enriches the chemical profiling of PG, and helps promoting the further development of therapeutic agents and nutraceutical products from PG.

Components study on antitussive effect and holistic mechanism of Platycodonis Radix based on spectrum-effect relationship and metabonomics analysis

The antitussive effect of Platycodonis Radix is closely related to the components in saponins fraction of Platycodonis Radix extract (SFPRE); however, these active components and their holistic mechanism remain unknown. Hence, a new method by integrating spectrum-effect relationship analysis with metabolomics analysis was applied to study the active components and their holistic mechanism simultaneously. For spectrum-effect relationship analysis, chemical fingerprints of ten batches of SFPRE were developed using UHPLC-LTQ-Orbitrap MSn; antitussive effect were evaluated using a classic mice-cough model induced by ammonia liquor. Spectrum-effect relationship was analyzed by partial least squares regression (PLSR) analysis. For metabolomics analysis, the altered metabolites related to cough in serum were identified by UHPLC-Q-TOF/MS and orthogonal partial least squares-discriminant analysis (OPLS-DA); metabolic pathway analysis was depended on MetaboAnalyst 4.0, KEGG database, METLIN database and HMDB database. Our findings showed that 10 identified components of Polygalacin D (peak 26), Deapio-platycodin D (peak 21), Platycodin D (peak 23), β-Gentiotriosyl platycodigenin (peak 37), Platycoside G3 (peak 17), Platycoside C (peak 25), Platycodin D3 (peak 16), 3-O-β-D-glucopyranosyl platycodigenin (peak 33), Platycoside F (peak 19) and 3″-O-acetyl platycodin D3 (peak 15), and 2 unidentified components (peak 45 and 44) possessed antitussive effects. The metabolomics analysis result showed that 19 metabolites were potential biomarkers related to the cough, 16 of which could be restored to normal levels by SFPRE. These biomarkers were involved in arachidonic acid metabolism, linoleic acid metabolism and glycerophospholipid metabolism. The current study may facilitate the development of antitussive medicines with fewer side-effects based on Platycodonis Radix.

A strategy to comprehensively and quickly identify the chemical constituents in Platycodi Radix by ultra-performance liquid chromatography coupled with traveling wave ion mobility quadrupole time-of-flight mass spectrometry

Quick identification of the complex composition of traditional Chinese medicine only through liquid-mass spectrometry technology is difficult. Especially the identification of isomers and co-eluting compounds is even more difficult. In this study, an approach of multidimensional data modes based on ultra-performance liquid chromatography coupled with traveling wave ion mobility quadrupole time-of-flight mass spectrometry was proposed to quickly and comprehensively identify the compounds in Platycodi Radix. First, data-independent acquisition, high-definition acquisition, and tandem mass spectrometry acquisition modes were used to acquire integrated multidimensional mass spectral data. Second, summarize the diagnostic ions of compounds according to the fragmentation pathway of references. Third, unknown compounds and isomers were identified via the UNIFI™ software with an in-house library. Finally, a total of 87 compounds were identified, seven compounds were explicitly identified by comparing the retention time and fragment ions with the references. Fourteen compounds were first detected in the Platycodi Radix, four of them tentatively were identified by comparing with previous literature, eight compounds were observed and reported for the first time by comparing typical fragmentation pathway with the known standard substances in this paper. This research strategy has a certain potential for the analysis of complex components of other traditional Chinese medicine.

Metabolite identification and pharmacokinetic study of platycodi radix (Jiegeng) in vivo

The secondary platycosides, 3-O-β-d-glucopyranosylplatycodigenin and 3-O-β-d-glucopyranosylplatyconic acid, were qualitatively and quantitatively analyzed in vivo for the first time.

Screening of Intestinal Bacterial Metabolites of Platycodin D Using Ultra-Performance Liquid Chromatography/Quadrupole Time-of-Flight Mass Spectrometry

Platycodin D (PD), a bioactive triterpenoid saponin isolated from Platycodi Radix (PR), possesses a vast range of biological activities. Although the pharmacological activities and pharmacokinetics of PD have been well demonstrated, information regarding the intestinal metabolisms of PD is very limited. In this study, human and rat fecal microflora were prepared and anaerobically incubated with PD at 37[Formula: see text]C for 48[Formula: see text]h, respectively. A highly sensitive and specific ultra performance liquid chromatography/quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF/MS) was developed for the analysis of PD and related metabolites in the reaction samples. A Liquid-liquid extraction method was used for sample pretreatment and the chromatographic separation was performed on a 1.7 [Formula: see text]m particle size Syncronis C[Formula: see text] column using gradient elution system. Finally, a total of seven metabolites were detected and tentatively identified, such as the demethylation metabolite (M1), deoxidation metabolites (M3, M7) and hydrolysis at the C-28 oligosaccharide metabolites (M5, M6), which were first discovered in this experiment. The results indicate that hydrolysis, demethylation, dehydroxylation, and acetylation were the major metabolic pathways of PDin vitro. Additionally, four bacterial strains from human feces including Enterococcus sp.41, Bacillus sp.46, Escherichia sp.49 A and Escherichia sp.64 were detected and further identified with 16S rRNA gene sequencing due to their relatively strong metabolic capacity toward PD. The present study provides important information about the metabolism of PD, which will help elucidate the impact of intestinal bacteria on this active component.

Pharmacokinetics, intestinal absorption and microbial metabolism of single platycodin D in comparison to Platycodi radix extract

Background:

Platycodi radix, the dried root of Platycodon grandiflorum A. DC, has been widely used as food and herb medicine for treating cough, cold and other respiratory ailments, and platycodin D (PD) is one of the most important compounds in Platycodi Radix.

Objective:

The purpose of this study was to compare the pharmacokinetic characteristics, intestinal absorption and microbial metabolism of PD in monomer with that in Platycodi radix extract (PRE).

Materials and Methods:

In the pharmacokinetic study, the concentrations of PD in rat plasma were determined by ultra-performance liquid chromatography-tandem mass spectrometry and the main pharmacokinetic parameters were calculated by data analysis software (DAS). Besides, in vitro Caco-2 cells and fecal lysate were performed to investigate the intestinal absorption and metabolism, respectively.

Results:

The results from pharmacokinetics showed that the area under the curve, the peak concentration the time to reach peak concentration and mean residence time of PD in PRE were enhanced significantly compared with that in single PD. Caco-2 cells transport study indicated that the absorption of PD both in monomer and in PRE were poor owning that the permeability of PD were <1/10⁶ cm/s. The hydrolysis degree of PD in PRE was significantly lower than that in monomer PD in fecal lysate, which might be illustrated by the other ingredients in PRE influenced the hydrolysis of PD via gut microbiota.

Conclusion:

These findings indicated that the difference of microbial metabolism, not apparent absorption in intestine for PD between in monomer and in PRE contributed to their pharmacokinetic difference.

Effects of Gancao on pharmacokinetic profiles of platycodin D and deapio-platycodin D in Jiegeng

ETHNOPHARMACOLOGICAL RELEVANCE

Jiegeng (Radix Platycodi), the dried root of Platycodon grandiflorum A. DC (Campanulaceae), has been used to treat cough, sore throat, bronchitis, and bronchial asthma for thousands of years. It is commonly prescribed with Gancao (Radix et Rhizoma Glycyrrhizae) as a herbal combination in traditional Chinese medicine (TCM) to produce synergistic effects.

AIM OF THE STUDY

To elucidate the herbaceous compatibility of Jiegeng and Gancao, we investigated the comparative pharmacokinetics, intestinal absorption, and microbial metabolism of platycodin D (PD) and deapio-platycodin D (DPD), the platycodins contained in Jiegeng.

MATERIALS AND METHODS

In the comparative pharmacokinetic study, the concentrations of PD and DPD in Jiegeng extract (JE) and the Jiegeng-Gancao herb pair (JGHP) were determined in rat plasma using liquid chromatography-tandem mass spectrometry (LC-MS/MS). In addition, the main pharmacokinetic parameters were calculated using data analysis software (DAS). Furthermore, in vitro studies using Caco-2 cells and fecal lysates were performed to contradistinguish the intestinal absorption and microbial metabolism of PD and DPD in JE from those in JGHP.

RESULTS

The peak concentration (Cmax) and area under the plasma concentration curve (AUC) of PD in rats orally administrated JGHP significantly increased compared to that in rats treated with JE. In addition, the time to reach peak concentration (Tmax) and half-life (t1/2) of PD and DPD in combination with JGHP were all prolonged compared with those of JE. There was no significant difference in the absorption of PD between JE and JGHP in Caco-2 cells. However, the hydrolysis of both PD and DPD in JGHP were weaker than that in JE after a 2-h incubation in fecal lysate which might be responsible for the different pharmacokinetic profiles of the platycodins in JE and JGHP.

CONCLUSION

In this study, we discovered that Gancao might influence the pharmacokinetic profiles of PD and DPD in Jiegeng. Furthermore, the difference in profiles may be attributable to the inequable microbial metabolism rather than intestinal absorption of the platycodins in JE and JGHP. The results of this study elucidated the pharmacokinetic compatibility and rationale for the use of JGHP.

An HPLC-MS/MS method for the quantitative determination of platycodin D in rat plasma and its application to the pharmacokinetics of Platycodi Radix extract

AIMS

To develop an HPLC-MS/MS method for the quantification of platycodin D (PD) in rat plasma, and to acquire the main pharmacokinetic parameters of PD after oral administration of pure PD or of Platycodi Radix extract (PRE) containing PD.

METHOD

Plasma samples were pretreated with solid-phase extraction using an Oasis® HLB SPE cartridge. Madecassoside was used as the internal standard (IS). Chromatographic separation was achieved on an ODS column (100 mm × 2.1 mm i.d., 3.5 μm) with a mobile phase consisting of acetonitrile/water (30 : 70, V/V) containing 0.1 mmol·L(-1) ammonium acetate at a flow rate of 0.25 mL·min(-1). The detection was performed on a triple quadruple tandem mass spectrometer using an electrospray ionization (ESI) source with a chromatographic run time of 3.0 min. The detection was operated by multiple reaction monitoring (MRM) of the transitions of m/z 1 223.6→469.2 for PD and of m/z 973.6→469.2 for madecassoside (IS), respectively.

RESULTS

The calibration curve was linear from 5 to 2 000 ng·mL(-1) (r(2) >0.99) with a lower limit of quantification (LLOQ) of 5 ng·mL(-1). The intra- and inter-day precision (relative standard deviation, RSD) values were below 15% and the accuracy (relative error, RE) was from -15% to +15% at three quality control (QC) levels. Plasma concentrations of PD were determined for 24 h after i.v. administration of PD, and oral administration of PD and PRE, respectively. The absolute oral bioavailability of PD in rats was found to be (0.48 ± 0.19)% when administered PD, and to be (1.81 ± 0.89)% when administered PRE.

CONCLUSION

The developed HPLC-MS/MS method was successfully applied to assess the pharmacokinetic parameters and oral bioavailability of PD in rats after administration of PD and Platycodi Radix extract.

Platycosides from the Roots of Platycodon grandiflorum and Their Health Benefits

The extracts and pure saponins from the roots of Platycodon grandiflorum (PG) are reported to have a wide range of health benefits. Platycosides (saponins) from the roots of PG are characterized by a structure containing a triterpenoid aglycone and two sugar chains. Saponins are of commercial significance, and their applications are increasing with increasing evidence of their health benefits. The biological effects of saponins include cytotoxic effects against cancer cells, neuroprotective activity, antiviral activity, and cholesterol lowering effects. Saponins with commercial value range from crude plant extracts, which can be used for their foaming properties, to high purity saponins such as platycodin D, which can be used for its health applications (e.g., as a vaccine adjuvant). This review reveals that platycosides have many health benefits and have the potential to be used as a remedy against many of the major health hazards (e.g., cancer, obesity, alzheimer's) faced by populations around the world. Methods of platycoside purification and analysis are also covered in this review.

Chemical profile- and pharmacokinetics-based investigation of the synergistic property of platycodonis radix in traditional Chinese medicine formula Shengxian decoction

ETHNOPHARMACOLOGICAL RELEVANCE

To investigate the synergistic property of Platycodonis radix (PG) in a classic traditional Chinese medicine (TCM) prescription Shengxian decoction (SXT) by combining chemical profile with pharmacokinetic analysis strategy. The synergized prescription consisted of Astragali radix, Anemarrhenae rhizoma, Bupleuri radix, and Cimicifuage rhizoma.

MATERIALS AND METHODS

Ultra-performance liquid chromatography/quadruple time-of-flight mass spectrometry (UPLC-Q-TOF/MS) was employed to investigate the chemical fingerprints of SXT and decreased SXT (SXT that removed Platycodonis radix, SXT-PG). A reliable LC-MS/MS method was developed to examine the pharmacokinetics of 9 marker compounds (including formononetin, calycosin-7-O-β-d-glucoside, ononin, caffeic acid, isoferulic acid, mangiferin, timosaponin E1, timosaponin B-II and timosaponin B) following oral administration of SXT and SXT-PG in rats. Both in vitro chemical profiles and in vivo pharmacokinetic parameters differences between SXT and SXT-PG were conducted.

RESULTS

By using UPLC-Q-TOF/MS method, a total of 25 compounds identified from SXT, including 13 triterpenoids, 5 caffeinic derivatives, 4 isoflavonoids and 3 xanthone glycosides. Comparing the chemical fingerprints between SXT and decreased SXT did not reveal significant difference in the chemical profile of other four TCMs. The improved pharmacokinetic profiles of mangiferin, timosaponin E1, timosaponin B-II and timosaponin B were found in SXT group, suggesting the quicker distribution and more effective absorption, when compared with those in the SXT-PG group.

CONCLUSIONS

These results indicated that PG did not increase the dissolution of synergized prescription when co-decocting, but guided the synergized prescription to target location, reflecting the courier role of PG, which was in line with the clinical principle of TCM. It also established a useful method for TCM synergistic property research.

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.

Glycosylated platycosides: identification by enzymatic hydrolysis and structural determination by LC-MS/MS

In this study, enzymatic hydrolysis and chemometric methods were utilized to discriminate glycosylated platycosides in the extract of Platycodi Radix by LC-MS. Laminarinase, whose enzymatic activity was evaluated using gentiobiose and laminaritriose, was a suitable enzyme to identify the glycosylated platycosides. The laminarinase produced deapi-platycodin D and platycodin D from the isolated deapi-platycoside E and platycoside E through the loss of two glucose units by enzymatic reaction, respectively. After hydrolyzing a crude extract by laminarinase, the reconstructed total ion chromatogram generated by a chemometric technique sorted peaks of deglycosylated platycosides easily. Structural information of the glycosylated isomers was revealed through fragment ions generated by the sodiated C0β ion corresponding to reduced disaccharides in the positive MS(4) spectra. Characteristic fragment ions of Glc-(1→6)-Glc moieties were observed through ring cleavages of (0,2)A0β, (0,3)A0β, and (0,4)A0β, whereas Glc-(1→3)-Glc moieties produced only (0,3)A0β ions. Lithium-adducted platycosides allowed more detailed structural analysis of glycosidic bond cleavage corresponding to Y1β and B1β in addition to ring cleavage.

Bioactivity-integrated ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry for the identification of nuclear factor-κB inhibitors and β2 adrenergic receptor agonists in Chinese medicinal preparation Chuanbeipipa dropping pills

A simple and dual-target method based on ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry combined with dual-bioactive [nuclear factor-κB (NF-κB) and β2 -adrenergic receptor] luciferase reporter assay systems was developed to rapidly characterize the chemical structure of various bioactive compounds of TCM preparations. Chuanbeipipa dropping pills, a traditional Chinese medicine preparation used for the clinical therapy of chronic obstructive lung disease and cough caused by bronchial catarrh, was analyzed with this method. Potential anti-inflammatory and spasmolytic constituents were screened using NF-κB and β2 -adrenergic receptor activity luciferase reporter assay systems and simultaneously identified according to the time-of-flight mass spectrometry data. One β2-adrenergic receptor agonist (ephedrine) and two structural types of NF-κB inhibitors (platycosides derivatives and ursolic acid derivatives) were characterized. Platycodin D3 and E were considered new NF-κB inhibitors. Further cytokine and chemokine detection confirmed the anti-inflammatory effects of the potential NF-κB inhibitors. Compared with conventional fingerprints, activity-integrated fingerprints that contain both chemical and bioactive details offer a more comprehensive understanding of the chemical makeup of plant materials. This strategy clearly demonstrated that multiple bioactivity-integrated fingerprinting is a powerful tool for the improved screening and identification of potential multi-target lead compounds in complex herbal medicines.

Enzymatic transformation of platycosides and one-step separation of platycodin D by high-speed countercurrent chromatography

Platycosides, the saponins found in the roots of Platycodon grandiflorum (Platycodi Radix), are typically composed of oleanane triterpenes with two side chains. In platycosides, platycodin D, a glucose unit at C-3, is a major component, which has several pharmacological activities. Because of the high demand for this compound, we attempted to enzymatically convert platycodin D(3) and platycoside E, having two and three glucose units at C-3, respectively, into platycodin D. In this study, we tested the ability of several glycosidases to transform platycosides, or more specifically, the ability to transform platycoside E and platycodin D(3) into platycodin D. To obtain pure platycodin D on a preparative scale, high-speed countercurrent chromatography with a solvent system of ethyl acetate/n-butanol/water (1.2:1:2, v/v/v) was used for the separation of the enzymatically transformed product. Approximately 39.4 mg of platycodin D (99.8% purity) was obtained from 200 mg of the product in a one-step separation. The results strongly support the advantage of enzymatic transformation of the platycosides for the efficient enrichment of platycodin D in the complicated extract of the medicinal plant.

O-glycoside sequence of pentacyclic triterpene saponins from Phytolacca bogotensis using HPLC-ESI/multi-stage tandem mass spectrometry

INTRODUCTION

The lack of pharmacopoeial methodologies for the quality control of plants used for therapeutic purposes is a huge problem that impacts directly upon public health. In the case of saponins, their great structural complexity, weak glycoside bonds and high polarity hinder their identification by conventional techniques.

OBJECTIVE

To apply high-performance liquid chromatography-electrospray tandem mass spectrometry (HPLC-ESI/MS(n)) to identify the O-glycoside sequence of saponins from the roots of Phytolacca bogotensis.

METHODOLOGY

Saponins were isolated by preparative HPLC and characterised by NMR spectroscopic experiments. Collision-induced dissociation (CID) of isolated saponins was performed producing typical degradation reactions that can be associated with several glycosidic bonds as empirical criteria. A method using solid-phase extraction (SPE) and HPLC/ESI-MS(n) for the characterisation of saponins and identification of novel molecules is described.

RESULTS

Three saponins reported for the first time in P. bogotensis were isolated and characterised by NMR spectroscopy. Characteristic cross ring cleavage reactions have been used as empirical criteria for the characterisation of the glycosidic bonds most frequently reported for Phytolacca saponins. One new saponin was proposed on the basis of empirical criteria, and other five saponins were identified for the first time for P. bogotensis using HPLC-ESI/MS(n).

CONCLUSION

Electrospray ionisation in combination with tandem mass spectrometry has been established as a powerful tool for the profiling of saponins from roots of P. bogotensis. CID proved to be a useful tool for the characterisation and identification of known and novel saponins from the plant family Phytolaccaceae and can be used for quality control purposes of crude plant extracts.

Isolation and tandem mass fragmentations of an anti-inflammatory compound from Aralia elata

One-step isolation of a saponin from Aralia elata was undertaken using high-speed countercurrent chromatography coupled with evaporative light scattering detection. A triterpenoid saponin, elatoside F, was purified with 96.8% purity using a two-phase-system comprising chloroform-methanol-water-isopropanol. The yield was 35.0 mg from 348.2 mg of the enriched saponin fraction. In vitro anti-inflammatory study demonstrated that elatoside F inhibited lipopolysaccharide-induced nitric oxide production, as well as nuclear factor kappaB activation, in a dose-dependent manner. Two types of mass ionization technique were compared on elatoside F to investigate characteristic fragmentation patterns. MALDI-TOF tandem mass spectrometric fragmentation patterns of sodiated ions provided structural information on glycosidic cleavages and on extensive cross-ring cleavages. Electrospray ionization multiple-stage tandem mass fragmentation of both sodiated and lithiated ions could provide information on glycosidic cleavages. All observed tandem mass fragmentation spectra provided valuable elatoside F structural information when unknown samples from crude extracts are under screening by mass spectrometry.