Search

Lonicera macranthoides (LM) and L. japonica (LJ) are medicinal plants widely used in treating viral diseases, such as COVID-19. Although the two species are morphologically similar, their secondary metabolite profiles are significantly different. Here, metabolomics analysis showed that LM contained ~86.01 mg/g hederagenin-based saponins, 2000-fold higher than LJ. To gain molecular insights into its secondary metabolite production, a chromosome-level genome of LM was constructed, comprising 9 pseudo-chromosomes with 40 097 protein-encoding genes. Genome evolution analysis showed that LM and LJ were diverged 1.30-2.27 million years ago (MYA). The two plant species experienced a common whole-genome duplication event that occurred ∼53.9-55.2 MYA before speciation. Genes involved in hederagenin-based saponin biosynthesis were arranged in clusters on the chromosomes of LM and they were more highly expressed in LM than in LJ. Among them, oleanolic acid synthase (OAS) and UDP-glycosyltransferase 73 (UGT73) families were much more highly expressed in LM than in LJ. Specifically, LmOAS1 was identified to effectively catalyse the C-28 oxidation of β-Amyrin to form oleanolic acid, the precursor of hederagenin-based saponin. LmUGT73P1 was identified to catalyse cauloside A to produce α-hederin. We further identified the key amino acid residues of LmOAS1 and LmUGT73P1 for their enzymatic activities. Additionally, comparing with collinear genes in LJ, LmOAS1 and LmUGT73P1 had an interesting phenomenon of 'neighbourhood replication' in LM genome. Collectively, the genomic resource and candidate genes reported here set the foundation to fully reveal the genome evolution of the Lonicera genus and hederagenin-based saponin biosynthetic pathway., (© 2023 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.)

After ingestion of ginseng, the bioavailability of its parent compounds is low and enteric microbiota plays an important role in parent compound biotransformation to their metabolites. Diet type can influence the enteric microbiota profile. When human subjects on different diets ingest ginseng, their different gut microbiota profiles may influence the metabolism of ginseng parent compounds. In this study, the effects of different diet type on gut microbiota metabolism of American ginseng saponins were investigated. We recruited six healthy adults who regularly consumed different diet types. These subjects received 7 days' oral American ginseng, and their biological samples were collected for LC-Q-TOF-MS analysis. We observed significant ginsenoside Rb 1 (a major parent compound) and compound K (a major active metabolite) level differences in the samples from the subjects consuming different diets. Subjects on an Asian diet had much higher Rb 1 levels but much lower compound K levels compared with those on a Western diet. Since compound K possesses much better cancer chemoprevention potential, our data suggested that consumers on a Western diet should obtain better cancer prevention effects with American ginseng intake compared with those on an Asian diet. Ginseng compound levels could be enhanced or reduced via gut microbiota manipulation for clinical utility., (Copyright © 2016 John Wiley & Sons, Ltd.)

The root and rhizome of Panax notoginseng (PNG) are used as folk medicine. Recent studies have reported PNG to possess immunomodulatory, cardioprotective, hepatoprotective, anti-diabetic and anticancer activities among a host of other pharmacological effects. The main active constituents responsible for these pharmacological effects are saponins. It has also been proven that the chemical constituents of steamed PNG differs from the raw form. Traditional methods of separating individual components in crude extracts are usually tedious, almost irreproducible and time-consuming. In this study, an automated multi-step preparative separation system, known as Sepbox afforded a quick, reproducible and fast separation of saponins from PNG. With Sepbox, a total of 11 saponins of high purity were obtained in a short period of time. The separated compounds were identified as notoginsenosides R1, T5, ginsenosides Rb1, Rg1, Rg2, Rh1, Rh4, Rd, 20 (S) -Rg3 and a mixture of ginsenosides Rk1 and Rg5., (Copyright © 2016 Elsevier B.V. All rights reserved.)

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., (Copyright © 2015 Elsevier B.V. All rights reserved.)

In this work, a rapid and simple method based on matrix solid-phase dispersion (MSPD) and ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was developed. Guge Fengtong preparation (GGFT), a traditional Chinese herbal medicine, was investigated for validation, and eight major constituents were determined including four saponins (protodioscin, protogracillin, pseudoprotodioscin and dioscin) and four gingerols (6-gingerol, 8-gingerol, 10-gingerol and 6-shogaol). Response surface methodology and desirability function were employed to optimize the extraction conditions, such as dispersant, dispersant/sample ratio, solvent concentration, and elution volume, of MSPD. Results showed that MSPD using C18 (1.75 g) as the dispersant material and methanol (89%, v/v) as the eluting solvent (12.00 mL) resulted in a high extraction efficiency. MSPD extraction had the advantages of combining extraction and clean-up in a single step, was less time consuming and required lower solvent volumes compared with conventional methods. Quantification of chemical compounds from GGFT preparations were performed using UPLC-MS/MS in multiple-reaction monitoring mode. The proposed method afforded a low limit of detection ranging from 0.02 to 0.40 ng for saponins and gingerols. For all the analytes, recoveries ranged from 80.9% to 103% and repeatabilities were acceptable with relative standard deviations of less than 6.81%. The proposed MSPD-UPLC-MS/MS method was successfully utilized to analyze five batches of GGFTs, and the results demonstrated that this method is simple, efficient and has potential to be applied for the quality control of herbal preparations.

As one of the most commonly used medicinal plants, ginseng has been an attractive model herb for study. A wide range of analytical methods has been used to characterize its constituents. However, less effort has been devoted to the rare ginseng saponins, especially their isomers and sugar linkages. In this study, we used segmental monitoring and diagnostic ion filtering to characterize ginseng saponins by rapid liquid chromatography with time-of-flight mass spectrometry (LC-TOF-MS). By using selected diagnostic ions, specific groups of ginseng saponins were readily extracted from the complicated matrix. 20(R) and 20(S) stereo-saponins were differentiated using the peak abundance ratio of [M-H(2)O+H](+) to [M-2H(2)O+H](+). The fragmentation behavior of ginsenosides was first reported in negative ion mode by MS/MS with high-energy collision-induced dissociation, producing rules to determine sugar numbers, positions and linkages. Using the rules, we identified and compared the nontarget ginseng saponin profiling of raw and steamed American ginseng roots and berries. We characterized 70 saponins in the samples. Our strategy can be extended to screen and characterize other rare ginseng saponins and their metabolites., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Oleanane-type triterpene saponins (OTS) are major active ingredients in Glycyrrhiza uralensis. In this work, a rapid-resolution liquid chromatography with time-of-flight mass spectrometry (RRLC/TOF-MS) method has been developed to characterize and identify OTS from G. uralensis. The major diagnostic ions and fragmentation pathways from thirteen OTS have been characterized for the first time. At a low fragmentor voltage of 120  V in positive ion mode, the precursor ion [M + H](+) or/and [M + Na](+) was obtained for accurate determination of molecular formula. When the fragmentor voltage was increased to 425  V, abundant characteristic fragment ions were observed for structural characterization. Neutral losses of sugar moieties, such as glucuronic acid (GlcA, 176  Da), glucose (Glc, 162  Da) and rhamnose (Rha, 146 Da), were commonly observed in the MS spectra for prediction of the sugar number and sequences. Other typical losses included AcOH (60  Da), CH(2)O (30  Da), 2 × H(2)O (2 × 18  Da) and HCOOH (46  Da) from [Aglycone + H-H(2)O](+) (named [B](+)), corresponding to the presence of a C(22)-acetyl group, C(24)-hydroxyl group, C(22)-hydroxyl group or C(30)-carboxyl group on the aglycone moiety, respectively. In particular, characteristic ring cleavages of the aglycone moieties on A- and B-rings were observed. Based on the fragmentation patterns of reference compounds, nineteen OTS have been identified in an extract of G. uralensis, thirteen of which were unambiguously identified and the other six were tentatively assigned., (2010 John Wiley & Sons, Ltd.)

A rapid-resolution liquid chromatography (RRLC) method coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry (Q-TOF MS/MS) has been developed for analysis of oleanane-type triterpenoid saponins in Achyranthes bidentata. Collision-induced dissociation techniques were used to fragment the precursor molecular ions and the resulting product ions. A retro-Diels-Alder rearrangement from the oleanane aglycone skeleton in the MS/MS process yielded characteristic fragment ions in positive ion mode. These characteristic ions were helpful in predicting the aglycone structure. Losses of monosaccharide sequences, presence of sugar-chain fragment ions, and cleavage of CO(2) were observed for important information on sugar types and attachment sequences. Fragmentation rules of three major groups of saponins from A. bidentata were summarized, and the possible fragmentation pathways were proposed. A total of 22 compounds including both the target and unknown oleanane-type triterpenoid saponins were rapidly screened and predicted in the herbal extract by the developed method. The RRLC-Q-TOF MS/MS method has provided a powerful approach for rapid separation, target screening and structural elucidation of oleanane-type saponins, and also opened perspectives for similar studies on other herbal medicines., (Copyright © 2010 John Wiley & Sons, Ltd.)

Investigation of characteristic constituents of the roots of Glycyrrhiza uralensis Fischer led to isolation of four new triterpene glucuronides, namely uralsaponins C-F (1-4), an artificial product, namely the methyl ester of glycyrrhizin (5), as well as six known triterpene glucuronides (6-11). These new compounds were identified by 1D and 2D NMR spectroscopic analysis. The cytotoxicity of the selected compounds and their aglycones were evaluated against HeLa and MCF-7 cancer cell lines, and the preliminary structure-activity relationship was also elucidated.

Asperosaponin VI (also named akebia saponin D) is a typical bioactive triterpenoid saponin isolated from the rhizome of Dipsacus asper Wall (Dipsacaceae). In this work, a sensitive high-performance liquid chromatography-electrospray ionization-mass spectrometry (HPLC-ESI-MS) assay has been established for determination of asperosaponin VI in rat plasma. With losartan as the internal standard (IS), plasma samples were prepared by protein precipitation with methanol. Chromatographic separation was performed on a C(18) column with a mobile phase of 10 mm ammonium acetate buffer containing 0.05% formic acid-methanol (32 : 68, v/v). The analysis was performed on an ESI in the selected ion monitoring mode using target ions at m/z 951.4 for asperosaponin VI and m/z 423.2 for the IS. The calibration curve was linear over the range 3-1000 ng/mL and the lower limit of quantification was 3.0 ng/mL. The intra- and inter-assay variability values were less than 9.5 and 7.8%, respectively. The accuracies determined at the concentrations of 3.0, 100.0, 300.0 and 1000 ng/mL for asperosaponin VI were within +/-15.0%. The validated method was successfully applied to a pharmacokinetic study in rats after oral administration of asperosaponin VI., (2009 John Wiley & Sons, Ltd.)

A high-performance liquid chromatography coupled with electrospray ionization time-of-flight mass spectrometry (HPLC-ESI-TOF-MS) method has been developed for qualitative and quantitative analysis of isoflavonoids and saponins, as well as for the quality control of Radix Astragali and its preparations. The selectivity, reproducibility and sensitivity are compared with HPLC with diode array detection (DAD) and evaporative light scattering detection (ELSD). Limits of detection and quantification fell in ranges of 9-40 and 23-103 ng/mL for 13 analytes with a injection of 10 microL samples, and all calibration curves showed good linear regression (r(2)>0.9938) within the test range. The assay was successfully utilized to analyze the 13 marker components in 20 samples of Radix Astragali products. The quantitative results demonstrated that samples from different localities and manufacturers showed different quality. Advantages, in comparison with conventional HPLC-DAD-ELSD, are that reliable identification of target compounds could be achieved by accurate mass measurements (<3 ppm) along with characteristic retention time, extracted ions chromatograms using a narrow mass window for quantification ensure that the chromatographic peaks are free from background or co-elutes interference, and the great enhancement in selectivity and sensitivity allows identification and quantification of low levels of constituents in complex Radix Astragali matrixes.

A liquid chromatography-electrospray ionization-mass spectrometry method has been developed and validated for identification and quantification of four major bioactive saponins in rat plasma after oral administration of extraction of saponins from Flos Lonicerae, i.e., macranthoidin B, macranthoidin A, dipsacoside B, and macranthoside B. Plasma samples were extracted with solid-phase extraction, separated on a Shim-pack CLC-ODS column and detected by MS in negative selective ion monitoring mode. Calibration curves offered linear ranges of two orders of magnitude with r(2)>0.999. The method showed the low limit quantification of 7.72, 6.06, 7.16, and 1.43 ng/mL for macranthoidin B, macranthoidin A, dipsacoside B, and macranthoside B, respectively. The inter- and intra-CV precision (R.S.D.) were all within 10% and accuracy (% bias) ranged from -10 to 10%. The overall recovery was more than 70%. This developed method was subsequently successfully applied to pharmacokinetic profiles of the four saponins in rats. After oral administration of extraction of saponins in rats, the concentration-time course was found to be the double peaks of curve.

A novel fast high-performance liquid chromatography (HPLC) method coupled with diode array detection (DAD) and time-of-flight mass spectrometry (TOF/MS) was developed for qualitative and quantitative analysis of Radix Astragali products. The potential of fast HPLC on 1.8-microm particles was compared with the performance of HPLC on conventional 5-microm particles columns. Significant advantages of fast HPLC include high-speed chromatographic separation, four times faster than HPLC with conventional columns, and great enhancement in sensitivity with limits of detection low to 0.001 ng. With dynamic adjustment of fragmentor voltage in TOF/MS, an efficient transmission of the ions was achieved to obtain the best sensitivity and abundant fragmentation. By accurate mass measurements within 5 ppm error for each molecular ion and subsequent fragment ions, a reliable identification and differentiation of six major saponins including two groups of isomers and twelve main isoflavonoids was described here for the first time. For quantitative analysis by fast HPLC-TOF/MS, linearity of response over two orders of magnitude was demonstrated (r(2)>0.99) for all analytes. Intra-day reproducibility was below 3% RSD and inter-day values were below 5% RSD. A good correlation (slope=1.1108, r(2)=0.9853) was observed for accuracy test. It is concluded that the fast and sensitive HPLC-DAD-TOF/MS is powerful in qualitative and quantitative analysis of complex herbal medicines in terms of time savings, sensitivity, selectivity, precision, accuracy as well as increasing sample throughout and lowering solvent consumption.

A novel rapid resolution liquid chromatography (RRLC) method coupled with diode-array detection (DAD) and time-of-flight mass spectrometry (TOFMS) in both positive and negative modes has been developed for quick and sensitive identification of the major compounds in Danggui Buxue Tang (DBT) preparation. Significant advantages of the use of RRLC with 1.8-microm porous particles include the much higher speed of chromatographic separation and great enhancement in sensitivity, compared with the conventional high-performance liquid chromatography (HPLC). With dynamic adjustment of the key role as fragmentor voltage in TOFMS, an efficient transmission of the ions was achieved to obtain the best sensitivity for providing the molecular formula for each analyte, and abundant fragment ions for structural information. The structural characterization of the major compounds in DBT was elucidated with authentic standards by DAD-TOF/MS, including phenolic acids, phthalides, saponins and isoflavonoids. The targets were rapidly screened from the complicated DBT matrix using a narrow mass window of 0.01 Da to restructure extracted ion chromatograms. By accurate mass measurements within 3 ppm error for each molecular ion and subsequent fragment ions, ten phenolic acids and phthalides including three groups of isomers, thirteen major saponins with a 20,24-epoxy-9,19-cyclolanostane-3,6,16,25-tetrol skeleton, sixteen isoflavonoids, corresponding glycosides, malonylglycosides, and acetylglycosides were identified in DBT preparation. The appropriate fragmentation pathways for them were also proposed based on definite elemental composition of the fragment ions., (Copyright (c) 2008 John Wiley & Sons, Ltd.)

A sensitive and reliable high-performance liquid chromatography-mass spectrometry (HPLC-MS) was developed and validated for simultaneous quantification of five main bioactive components, i.e., calycosin-7-O-beta-D-glucoside, ononin, astragaloside IV, astragaloside I and ferulic acid in rat plasma after oral administration of Danggui Buxue Tang (DBT) extract. Plasma samples were extracted with solid-phase extraction (SPE) separated on an Inertsil ZORBAX C(18) column and detected by MS with electrospray ionization (ESI) interface in negative selective ion monitoring (SIM) mode. Calibration curves offered linear ranges of two orders of magnitude with r(2)>0.99. The method had the lower limit quantification of 0.55, 0.46, 1.07, 1.12 and 4.6 ng/mL for calycosin-7-O-beta-D-glucoside, ononin, astragaloside IV, astragaloside I and ferulic acid, respectively, with precision less than 10%. The RSD of intra- and inter-day variations ranged from 2.10% to 6.19% and 2.37% to 6.72%. This developed method was subsequently applied to pharmacokinetic studies of the five compounds in rats successfully.

A herb-combined prescription, mainly derived from roots of Salvia miltiorrhiza and Panax notoginseng, has been widely used for improving coronary or cerebral circulation in China as well as in Western countries. Multiple commercially available preparations, known as Fufang Danshen preparations (FDPs), produced by various manufacturers with the raw materials from different sources, pose a serious challenge to the quality control of this herb medicine. Previous pharmacological studies identify three types of bioactive components correlated with the clinical effect of those herb preparations. Those mainly include four phenolic acids, four saponins and four diterpenoid quinones. In this report, by using high performance liquid chromatography (HPLC) coupled with diode array and evaporative light scattering detectors (DAD-ELSD), we developed an improved quality control method for those herb medicines. A simultaneous separation and quantification of the 12 components was performed on a C(18) column, in which the mobile phase consisted of (A) 0.1% aqueous formic acid and (B) acetonitrile using a gradient elution. The optimum detection wavelength was set at 281 nm, the drift tube temperature of ELSD was set at 113 degrees C, the nitrogen flow rate at 3.1L/min, and the gain=4. All calibration curves showed good linear regression (r(2)>0.9927) within test ranges. The method developed showed good precision and accuracy with overall intra- and inter-day variations of 0.64-4.79% and 0.69-4.96%, respectively, and the overall recoveries of 93.50-107.69% for the 12 compounds analyzed. This method was successfully applied to quantify the twelve components in ten commercial samples from three formulas by seven independent manufacturers. This readily available, low-cost and reliable HPLC-DAD-ELSD method improved the quality control of traditional Chinese medicinal preparations consisting of complex compounds with different structures such as FDPs.

A method, HPLC coupled with diode-array and evaporative light scattering detectors (HPLC-DAD-ELSD), was newly developed to evaluate the quality of Flos Lonicerae (FL) and Flos Lonicerae Japonicae (FLJ), through a simultaneous determination of multiple types of bioactive components. By employing DAD, the detection wavelengths were set at 240 nm for the determination of iridoids, 330 nm for phenolic acids, and 360 nm for flavonoids, respectively. While ELSD, connected in series after DAD, was applied to the determination of saponins. This assay was fully validated with respect to precision, repeatability, and accuracy. Moreover, principal component analysis (PCA) was used for the similarity evaluation of different samples, and it was proven straightforward and reliable to differentiate FL and FLJ samples from different origins. For PCA, two principal components have been extracted. Principal component 1 (PC1) influences the separation between different sample sets, capturing 54.598% variance, while principal component 2 (PC2) affects differentiation within sample sets, capturing 12.579% variance. In conclusion, simultaneous quantification of bioactive components by HPLC-DAD-ELSD coupled with PCA would be a well-acceptable strategy to differentiate the sources and to comprehensively control the quality of the medicinal plants FL and FLJ.

A simple, rapid, and reliable method, namely high-performance liquid chromatography coupled with diode array and evaporative light scattering detectors (HPLC-DAD-ELSD), was developed to simultaneously determine twelve major flavonoids and five main saponins in different parts of the medicinal plant Huang-qi (Radix Astragali). The DAD wavelength was set at 280 nm for the UV detection of flavonoids, while the drift tube temperature was set at 105 degrees C and the nebulizing gas flow rate at 2.7 L/min for ELSD detection of saponins. The method was fully validated with respect to linearity (r2 >0.998), sensitivity, precision, and accuracy (recovery rate between 93.3 and 104.2%). The analytical results of different parts of the medicinal plant Huang-qi revealed that the levels of total flavonoids or saponins in individual parts can vary considerably and the concentration of each compound in different parts is also significantly different. The aerial parts (stems and leaves) contain even higher total contents of flavonoids (although of different kinds) than the commonly used roots of the plants. In addition, the concentration of total flavonoids and saponins in the extract of the fibrous roots was surprisingly highest among all parts of Astragalus species. All of these findings provide clear evidence and scientific support for utilization of different parts of the medicinal plant Huang-qi and also for reduction in waste of plant resources.

A method, high-performance liquid chromatography coupled with diode array and evaporative light scattering detectors (HPLC-DAD-ELSD), was developed to evaluate the quality of Radix Astragali through a simultaneous determination of six major active isoflavonoids and four main saponins. The wavelength at 280 nm was chosen to determine six isoflavonoids: calycosin-7-O-beta-D-glucoside (1), ononin (2), (6alphaR, 11alphaR)-9,10-dimethoxypterocarpan-3-O-beta-D-glucoside (3), (3R)-2'-hydroxy-3',4'-dimethoxyisoflavan-7-O-beta-D-glucoside (4), calycosin (5), and formononetin (6); and ELSD connected after DAD was employed to determine four saponins: astragaloside IV (7), astragaloside II (8), astragaloside I (9), and acetylastragaloside I (10). This assay was fully validated with respect to precision, repeatability and accuracy. The proposed method was successfully applied to quantify the ten components in eleven samples from different localities in China; significant variations were demonstrated in the content of these compounds in the samples from different areas. This simple, rapid, low-cost and reliable HPLC-DAD-ELSD method is suitable for routine quantitative analysis and quality control of traditional Chinese medicines (TCMs) consisting of bioactive multi-components with different structures such as Radix Astragali.

American ginseng is a commonly consumed herbal medicine in the United States and other countries. Ginseng saponins are considered to be its active constituents. We have previously demonstrated in an in vitro experiment that human enteric microbiota metabolize ginseng parent compounds into their metabolites. In this study, we analyzed American ginseng saponins and their metabolites in human plasma, urine and feces samples by liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (LC-Q-TOF-MS). Six healthy male volunteers ingested 1 g of American ginseng twice a day for 7 days. On day 7, biological samples were obtained and pretreated with solid phase extraction. The ginseng constituents and their metabolites were characterized, including 5 ginseng metabolites in plasma, 10 in urine, and 26 in feces. For the plasma, urine and feces samples, the levels of ginsenoside Rb 1 (a major parent compound) were 8.6, 56.8 and 57.7 ng/mL, respectively, and the levels of compound K (a major metabolite) were 58.4 ng/mL, 109.8 ng/mL and 10.06 μg/mL, respectively. It suggested that compound K had a remarkably high level in all three samples. Moreover, in human feces, ginsenoside Rk 1 and Rg 5 , Rk 3 and Rh 4 , Rg 6 and F 4 were detected as the products of dehydration. Further studies are needed to evaluate the pharmacological activities of the identified ginseng metabolites. [ABSTRACT FROM AUTHOR]

Abstract: American ginseng is a widely used natural product. Ginseng products are usually taken orally, and human intestinal microflora may metabolize ginsenosides. Existing publications report the metabolite fates of ginsenosides. However, investigations on the comprehensive metabolic profile of American ginseng extract are absent because of the chemical complexity and limitation of analytical methods. In this work, we studied the biotransformation and metabolic profile of American ginseng extract by human intestinal microflora. Human fecal microflora was prepared from a healthy Chinese man and then anaerobically incubated with American ginseng sample at 37°C for 24h. A rapid and simple liquid–liquid extraction method was used for sample pretreatment. A highly sensitive and selective liquid chromatography/quadrupole time-of-flight mass spectrometry (LC–Q-TOF-MS) method was used to characterize ginsenosides and related metabolites in the reaction samples. The LC–Q-TOF-MS provides superior data quality and advanced analytical capabilities for profiling, identifying, and characterizing complex metabolites in matrix-based biological samples. A total of 25 metabolites were detected, 13 of which were undoubtedly assigned by comparison with reference compounds, and 12 others were tentatively identified. The three most abundant metabolites are 20S-ginsenoside Rg3, ginsenoside F2 and compound K. The main metabolic pathways of ginseng saponins are deglycosylation reactions by intestinal microflora through stepwise cleavage of sugar moieties. Subsequent dehydration reactions also occur. Protopanaxadiol- and oleanane-type triterpenoids are easy to metabolize. The intestinal microbiota may play an important role in mediating the metabolism bioactivity of American ginseng. [Copyright &y& Elsevier]

Abstract: Various analytical technologies have been developed for quantitative determination of marker compounds in herbal medicines (HMs). One important issue is matrix effects that must be addressed in method validation for different detections. Unlike biological fluids, blank matrix samples for calibration are usually unavailable for HMs. In this work, practical approaches for minimizing matrix effects in HMs analysis were proposed. The matrix effects in quantitative analysis of five saponins from Panax notoginseng were assessed using high-performance liquid chromatography (HPLC). Matrix components were found to interfere with the ionization of target analytes when mass spectrometry (MS) detection were employed. To compensate the matrix signal suppression/enhancement, two matrix-matched methods, standard addition method with the target-knockout extract and standard superposition method with a HM extract were developed and tested in this work. The results showed that the standard superposition method is simple and practical for overcoming matrix effects for quantitative analysis of HMs. Moreover, the interference components were observed to interfere with light scattering of target analytes when evaporative light scattering detection (ELSD) was utilized for quantitative analysis of HMs but was not indicated when Ultraviolet detection (UV) were employed. Thus, the issue of interference effects should be addressed and minimized for quantitative HPLC–ELSD and HPLC–MS methodologies for quality control of HMs. [Copyright &y& Elsevier]