Separation and Quantification of Selected Sapogenins Extracted from Nettle, White Dead-Nettle, Common Soapwort and Washnut.

Saponins are an important group of secondary metabolites naturally occurring in plants with important properties like: antibacterial, antiviral and antifungal. Moreover, they are widely used in the cosmetic industry and household chemistry. The sapogenins are saponin hydrolyses products, frequently used to facilitate saponin detection. In the present study, an improved methodology for isolation and separation of five sapogenins extracted from nettle (Urtica dioica L.), white dead-nettle (Lamium album L.), common soapwort (Saponaria officinalis L.) and washnut (Sapindus mukorossi Gaertn.) was developed using ultra-high-performance liquid chromatography with an evaporative light-scattering detector (UHPLC-ELSD). Based on quantitative analysis, the highest content of hederagenin (999.1 ± 6.3 µg/g) and oleanolic acid (386.5 ± 27.7 µg/g) was found in washnut extracts. Good recoveries (71% ± 6 up to 99% ± 8) were achieved for four investigated targets, while just 22.2% ± 0.5 was obtained for the fifth one. Moreover, hederagenin and oleanolic acid of whose highest amount was detected in washnut (999.1 ± 6.3 µg/g and 386.5 ± 27.7 µg/g, respectively) were subject to another approach. Consequently, liquid chromatography coupled mass spectrometry (LC/MS) with multiple reaction monitoring mode (MRM) was used as an additional technique for fast and simultaneous identification of the mentioned targets.

Qualitatively and quantitatively investigating the metabolism of 20(S)-protopanaxadiol-type ginsenosides by gut microbiota of different species.

Ginsenosides Rb1, Rb2, Rb3 and Rc, four major protopanaxadiol (PPD)-type ginsenosides, can be metabolized by gut microbiota. The composition of gut microbiota varies in different species. Existing publications have reported the metabolite fates of ginsenosides by gut microbiota from single species. However, their microbiota-related metabolic species differences have not been evaluated yet. In current study, in vitro anaerobic incubations of PPD-type ginsenosides with gut microbiota from humans, rabbits and rats were conducted. The metabolites of each ginsenoside were then identified by LC-MS. A total of 15 metabolites from the four ginsenosides were identified. The major metabolic pathways were stepwise removals of the C-20 and C-3 sugar moieties to obtain aglycone PPD. The results showed that the hydrolysis rate of C-20 terminal ß-D-glucopyranosyl was significantly higher than those of α-L-arabinopyranosyl, ß-D-xylopyranosyl and α-L-arabinofuranosyl in different species. The activity of ß-glucosidase, the metabolic rates of parent compounds and the formation rates of their metabolites were significantly higher in gut microbiota from rabbits than from humans and rats. Our research draws researchers' attention to the species differences of microbiota-related drug metabolism.

Spirostanol Sapogenins and Saponins from Convallaria majalis L. Structural Characterization by 2D NMR, Theoretical GIAO DFT Calculations and Molecular Modeling.

Two new spirostanol sapogenins (5ß-spirost-25(27)-en-1ß,2ß,3ß,5ß-tetrol 3 and its 25,27-dihydro derivative, (25S)-spirostan-1ß,2ß,3ß,5ß-tetrol 4) and four new saponins were isolated from the roots and rhizomes of Convallaria majalis L. together with known sapogenins (isolated from Liliaceae): 5ß-spirost-25(27)-en-1ß,3ß-diol 1, (25S)-spirostan-1ß,3ß-diol 2, 5ß-spirost-25(27)-en-1ß,3ß,4ß,5ß-tetrol 5, (25S)-spirostan-1ß,3ß,4ß,5ß-tetrol 6, 5ß-spirost-25(27)-en-1ß,2ß,3ß,4ß,5ß-pentol 7 and (25S)-spirostan-1ß,2ß,3ß,4ß,5ß-pentol 8. New steroidal saponins were found to be pentahydroxy 5-O-glycosides; 5ß-spirost-25(27)-en-1ß,2ß,3ß,4ß,5ß-pentol 5-O-ß-galactopyranoside 9, 5ß-spirost-25(27)-en-1ß,2ß,3ß,4ß,5ß-pentol 5-O-ß-arabinonoside 11, 5ß-(25S)-spirostan-1ß,2ß,3ß,4ß,5ß-pentol 5-O-galactoside 10 and 5ß-(25S)-spirostan-1ß,2ß,3ß,4ß,5ß-pentol 5-O-arabinoside 12 were isolated for the first time. The structures of those compounds were determined by NMR spectroscopy, including 2D COSY, HMBC, HSQC, NOESY, ROESY experiments, theoretical calculations of shielding constants by GIAO DFT, and mass spectrometry (FAB/LSI HR MS). An attempt was made to test biological activity, particularly as potential chemotherapeutic agents, using in silico methods. A set of 12 compounds was docked to the PDB structures of HER2 receptor and tubulin. The results indicated that diols have a higher affinity to the analyzed targets than tetrols and pentols. Two compounds (25S)-spirosten-1ß,3ß-diol 1 and 5ß-spirost-25(27)-en-1ß,2ß,3ß,4ß,5ß-pentol 5-O-galactoside 9 were selected for further evaluation of biological activity.

Highly selective monitoring of in-source fragmentation sapogenin product ions in positive mode enabling group-target ginsenosides profiling and simultaneous identification of seven Panax herbal medicines.

In-source fragmentation of ginsenosides in the positive ESI mode (pISF-G) frequently occurs, which results in little fragment information useful for the structural elucidation. We are aimed to unveil the genesic mechanism and explore its potential significance in quality control of Ginseng and the related compound formulae. By applying six high-resolution mass spectrometers from Agilent, Waters, and Thermo Fisher, we could primarily demonstrate the susceptibility of pISF-G. The ion clusters in the positive full-scan MS1 spectra were generated from the protonated sapogenins by successive elimination of H2O, and showed specificity for ginsenoside classification. Selective ion monitoring (SIM) of the sapogenin product ions could delineate group-target ginsenoside profiles from Ginseng. A high-selectivity characteristic chromatogram (CC) was elaborated for Ginseng, on the Vion™ IMS-QTOF mass spectrometer by IM (ion mobility) separation and quadrupole filtering of four sapogenin fragments (m/z 407.37/CCS 206.24 Å2; m/z 423.36/CCS 211.26 Å2; m/z 439.36/CCS 209.60 Å2; m/z 457.37/CCS 217.81 Å2). Chemometric analysis, based on the CC data of seven Ginseng drugs (P. ginseng, P. quinquefolius, P. notoginseng, Red ginseng, leaf of P. ginseng, P. japonicus, and P. japonicus var. major), disclosed 35 marker compounds. We could readily discriminate among P. ginseng, P. quinquefolius, and P. notoginseng, in 15 different compound formulae by identifying these marker compounds on both the Vion IMS-QTOF and QTrap 4500 mass spectrometers. Conclusively, SIM of the pISF-G sapogenin product ions renders a new concept of CC enabling the group-target profiling of ginsenosides and authentication of Ginseng and the related compound formulae.

[Determination of five protopanaxadiol ginsenosides in ginseng by solid-phase extraction-ultra performance liquid chromatography].

A new method based on solid-phase extraction-ultraperformance liquid chromatography (SPE-UPLC) was developed for the determination of five protopanaxadiol ginsenosides in ginseng. The ginsenosides were extracted from ground ginseng samples using water-saturated n-butanol and purified on a hydrophilic solid-phase extraction column. Chromatographic separation was achieved on an ACQUITY UPLC BEH Shield RP18 column (100 mm×2.1 mm, 1.7 µm) by linear gradient elution using an acetonitrile/water mobile phase. Five protopanaxadiol ginsenosides were detected by a photodiode array detector, and they showed a strong positive linear correlation (r2>0.999) in the range of 5-500 µg/mL. In addition, the instrument precision ranged between 0.95% and 2.62% (n=6), with the sample stability between 0.90% and 2.15% (n=8) within 22 h. Intra- and inter-day repeatabilities were 5.35%-6.47% (n=6) and 5.56%-6.34% (n=8), respectively. Sample recoveries and the corresponding relative standard deviations (RSDs) were 87.16%-101.92% and 1.54%-4.01% (n=6), respectively. Hydrophilic chromatography materials were used in SPE, and the extract was directly loaded and purified without pretreatment. Besides, with the use of UPLC, the analysis time was greatly shortened. The developed method is simple and rapid, with high throughput, thus being suitable for the quantitative analysis of the five protopanaxadiol ginsenosides in ginsengs.

[Study on transformation rules of terrestrosin D in course of Tribuli Fructus stir-frying based on simulated processing technology].

The contents of terrestrosin D and hecogenin from Tribuli Fructus were determined before and after stir-frying. The results showed that the content of terrestrosin D was decreased significantly,and the content of hecogenin was increased significantly after such processing. In order to verify the inference that terrestrosin D was converted to hecogenin by stir-frying,the quantitative variation rules of terrestrosin D and hecogenin were studied by simulated processing technology,and the simulated processing product of terrestrosin D was qualitatively characterized by ultra performance liquid chromatography/time of flight mass spectrometry( UPLC-TOF/MS) to clarify its transformation process during stir-frying. The results showed that the content of terrestrosin D was decreased significantly at first and then a platform stage appeared with the prolongation of processing time at a certain temperature. Raising the stir-frying temperature could further decrease the content of terrestrosin D and delay the time that the platform stage appeared. When the processing was simulated at higher temperatures( 220 ℃ and 240 ℃),the content of hecogenin was increased gradually with the increase of processing temperature and the prolongation of processing time. In the process of stir-frying,the deglycosylation reaction of terrestrosin D to hecogenin was not completed in one step. The deglycosylation reaction occurred first at the end of the sugar chain,and then other glycosyl units in the sugar chain were sequentially removed from the outside to the inside to finally form the hecogenin. This study provides a basis for further revealing the detoxification mechanism of stir-fried Tribuli Fructus.

Transcriptome analysis of 1- and 3-year-old Panax notoginseng roots and functional characterization of saponin biosynthetic genes DS and CYP716A47-like.

MAIN CONCLUSION: Transcriptome analysis revealed high expression of saponin biosynthetic genes may account for highly accumulated saponins in 3-year-old Panax notoginseng roots and DS and CYP716A47 - like were functionally verified by transgenic tobacco. Panax notoginseng is a well-known traditional medical herb that contains bioactive compounds known as saponins. Three major dammarene-type triterpene saponins including R1, Rb1, and Rg1 were found to be highly accumulated in the roots of 3-year-old plants when compared to those of 1-year-old plants. However, the underlying cellular mechanism is poorly understood. In this study, transcriptome analysis revealed that most genes involved in saponin biosynthesis in P. notoginseng roots augmented during their growth periods. The analysis of the KEGG pathway indicated that the primary metabolism, cell growth, and differentiation were less active in the roots of 3-year-old plant; however, secondary metabolisms were enhanced, thus providing molecular evidence for the harvesting of P. notoginseng roots in the 3rd year of growth. Furthermore, the functional role of DS and CYP716A47-like, two of the candidate genes involved in saponin biosynthesis isolated from P. notoginseng, were verified via overexpression in cultivated tobacco. Approximately, 0.325 µg g-1 of dammarenediol-II and 0.320 µg g-1 of protopanaxadiol were recorded in the dry leaves of transgenic tobacco overexpressed with DS and both DS and CYP716A47-like, respectively. This study provides insights into the molecular mechanisms for saponin accumulation in P. notoginseng roots during its growth period and paves a promising way to produce dammarenediol-II and protopanaxadiol via transgenic techniques.

Pharmacokinetic interaction of calcitriol with 20(S)-protopanaxadiol in mice: Determined by LC/MS analysis.

The physiological and anti-cancer functions of vitamin D3 are accomplished primarily via 1α,25-dihydroxyvitamin D3 (calcitriol), whereas 20(S)-protopanaxadiol (aPPD) is a ginsenoside, which is isolated from Panax ginseng, with potential anti-cancer benefits. In the present study, we report a pharmacokinetic (PK) herb-nutrient interaction between calcitriol and aPPD in mice. A liquid chromatography mass spectrometry (LC/MS) method was developed using 4-phenyl-1,2,4-triazoline-3,5-dione derivatizing agent and we subsequently used the method to quantitate calcitriol in mouse serum. The limit of quantitation was 0.01 ng/ml which is approximately 100 fold lower than the previously reported assay from our laboratory. Calcitriol PK parameters were determined in non-tumor-bearing or C4-2 human prostate tumor-bearing nude mice following oral co-administration of calcitriol either alone or in combination with aPPD. Mice were pretreated with oral aPPD (70 mg/kg) or vehicle control twice daily for seven consecutive days, followed by a single oral dose of 4 µg/kg calcitriol alone or in combination with aPPD. Our PK results demonstrated that co-administration of calcitriol with aPPD (following pre-treatment with vehicle for seven days) resulted in a 35% increase in the area under the curve (AUC0-24 h) and a 41% increase in the maximum serum concentration (Cmax) compared to the calcitriol only group. aPPD therefore significantly increased calcitriol serum exposure. We also saw a reduction in the time required to reach Cmax. In contrast, calcitriol PK in mice co-administered with calcitriol and aPPD as well as those pretreated seven consecutive days with aPPD was no different than that determined for the mice that received vehicle for seven days as pre-treatment. Co-administration of calcitriol with aPPD therefore could increase health benefits of vitamin D3, however any increased risk of hypercalcemia, resulting from this combination approach, requires further investigation. Lastly, we surmise that a cytochrome P450 inhibition-based mechanism may contribute to the observed PK interaction.

Efficient Biotransformation of Astragaloside IV to Cycloastragenol by Bacillus sp. LG-502.

Cycloastragenol (CA), an exclusive telomerase activator, was derived from the Astragali Radix which is widely distributed in Turkey. Until now, there is no report to produce CA with effective and environment-friendly methods. Biotransformation is considered to be a promising technology. Thus, the present study was aimed to establish a biotransformation technology that could efficiently produce CA. In this paper, a microorganism, LG-502, was used to successfully transform astragaloside IV (ASI) to CA by analysis of thin layer chromatography (TLC) and high-performance liquid chromatography (HPLC). The phylogenetic analysis of the 16S rRNA indicated that this strain belongs to Bacillus sp. Three metabolites were separated during the fermentation and characterized to be cyclogaleginoside B, CA, and 20R, 24S-epoxy-6α, 16ß, 25-trihydroxy-9, 19-cycloartan-3-one based on NMR and MS spectroscopic analyses. The conversion rate of ASI and yield rate of CA were achieved as high as 89 and 84%, respectively, under optimized conditions. Enzymatic analysis showed that the glycosidases were mainly located inside the bacterial body, and the activities of glucosidases were much higher than the xylosidases under the experimental conditions. This study provides a feasible, effective, and eco-friendly way to prepare CA from ASI, which might greatly contribute to the applications of ASI.

A Metabolomic Approach for the Discrimination of Red Ginseng Root Parts and Targeted Validation.

Ginsenosides are used as existing markers of red ginseng (RG) quality, and ginsenoside ratios are also indicative of the different components of red ginseng. For the analysis and classification of ginsenoside content, red ginseng was separated into three parts, namely, main roots, lateral roots, and fine roots, and each extract was subjected to ultra-performance liquid chromatography quadruple time-of-flight mass spectrometry (UPLC-QToF-MS) with multivariate statistical analysis. Principal component analysis (PCA) showed a clear discrimination between the extracts of main roots and fine roots and suggested discrimination markers (four for the main roots and five for the fine roots). The fine root markers were identified as ginsenoside. We identified two markers for the main roots of red ginseng in this study. Moreover, the contents of 22 ginsenosides were analyzed in all three components of red ginseng. Fine roots have the highest protopanaxadiol (PPD)/protopanaxatriol (PPT) ratio. The PPD group of ginsenosides, which is quantitatively dominant in fine roots, clearly distinguishes the main roots from the other parts.

Combination of HPLC-MS and QAMS as a new analytical approach for determination of saponins in ginseng containing products.

Conventional liquid chromatographic methods coupled with ultraviolet detection with low-wavelength range are lacking selectivity and sensitivity to determine both polar and less polar ginsenosides. Also the lack of standard substances for such quality control methods is leading to development of the approaches using single standard for quantitative analysis of multi-component system (QAMS). The objective of present study was to establish and compare for the first time liquid chromatography-ultraviolet detection and liquid chromatography-mass spectrometry QAMS methods for the simultaneous determination of protopanaxatriol-type and protopanaxadiol-type ginsenosides in a variety of ginseng products. Sixteen polar and less polar ginsenosides were separated on a reversed-phase C18-column (150mm×2.0mm, 2.2µm) with a mobile phase consisting of 0.1% formic acid in water and acetonitrile. Components were then detected by means of ultraviolet and mass spectrometry detection. Characteristic sapogenin fragmentation signals with m/z 423 and 425 for two major groups of ginseng saponins allowed their simultaneous determination in a single chromatographic run, while the use of ultraviolet detection tends to give overvalued results. Structural correlation between the relative response factors and saponin structure was demonstrated. The method was linear (R2 >0.999) and sensitive (LODs, 0.01-0.03mg/mL) within the concentration range tested. Concentrations of individual ginsenosides and several quality control parameters were determined in ginseng root extracts and commercial ginseng products of different types (root slices, tablets and tea samples), and results showed that ginsenoside content can be successfully measured by means of QAMS approach.

Optimization of a cytochrome P450 oxidation system for enhancing protopanaxadiol production in Saccharomyces cerevisiae.

Ginsenosides, the major bioactive components of Panax ginseng, are regarded as promising high-value pharmaceutical compounds. In ginseng, ginsenosides are produced from their precursor protopanaxadiol. Recently, an artificial biosynthetic pathway of protopanaxadiol was built in Saccharomyces cerevisiae by introducing a P. ginseng dammarenediol-II synthase, a P. ginseng cytochrome P450-type protopanaxadiol synthase (PPDS), and a Arabidopsis thaliana NADPH-cytochrome P450 reductase (ATR1). In this engineered yeast strain, however, the low metabolic flux through PPDS resulted in a low productivity of protopanaxadiol. Moreover, health of the yeast cells was significantly affected by reactive oxygen species released by the pool coupling between PPDS and ATR1. To overcome the obstacles in protopanaxadiol production, PPDS was modified through transmembrane domain truncation and self-sufficient PPDS-ATR1 fusion construction in this study. The fusion enzymes conferred approximately 4.5-fold increase in catalytic activity, and 71.1% increase in protopanaxadiol production compared with PPDS and ATR1 co-expression. Our in vivo experiment indicated that the engineered yeast carrying fusion protein effectively converted 96.8% of dammarenediol-II into protopanaxadiol. Protopanaxadiol production in a 5 L bioreactor in fed-batch fermentation reached 1436.6 mg/L. Our study not only improved protopanaxadiol production in yeast, but also provided a generic method to improve activities of plant cytochrome P450 monooxygenases. This method is promising to be applied to other P450 systems in yeast. Biotechnol. Bioeng. 2016;113: 1787-1795. © 2016 Wiley Periodicals, Inc.

A new triterpenoid saponin from Clinopodium chinense (Benth.) O. Kuntze.

A new triterpene saponin, 3ß,16ß,23α,28ß,30ß-pentahydroxyl-olean-11,13(18)-dien-3ß-yl-[ß-D-glucopyranosyl-(1→2)]-[ß-D-glucopyranosyl-(1→3)]-ß-D-fucopyranoside, was named Clinoposaponin D (1), together with six known triterpene saponins, buddlejasaponin IVb (2), buddlejasaponin IVa (3), buddlejasaponin IV (4), clinopodisides D (5), 11α,16ß,23,28-Tetrahydroxyolean-12-en-3ß-yl-[ß-D-glucopyranosyl-(1→2)]-[ß-D-glucopyranosyl-(1→3)]-ß-D-fucopyranoside (6) and prosaikogenin A (7), and two known triterpenes, saikogenin A (8) and saikogenin F (9) were isolated from Clinopodium chinense (Benth.) O. Kuntze. Their structures were elucidated on the basis of 1D, 2D NMR and MS analysis. Meanwhile, the effects of all compounds on rabbit platelet aggregation and thrombin time (TT) were investigated in vitro. Compounds 4 and 7 had significant promoting effects on platelet aggregation with EC50 value at 53.4 and 12.2 µM, respectively. In addition, the highest concentration (200 µM) of compounds 2 and 9 shortened TT by 20.6 and 25.1%, respectively.

Fast Centrifugal Partition Chromatography Fractionation of Concentrated Agave (Agave salmiana) Sap to Obtain Saponins with Apoptotic Effect on Colon Cancer Cells.

Separation of potentially bioactive components from foods and plant extracts is one of the main challenges for their study. Centrifugal partition chromatography has been a successful technique for the screening and identification of molecules with bioactive potential, such as steroidal saponins. Agave is a source of steroidal saponins with anticancer potential, though the activity of these compounds in concentrated agave sap has not been yet explored. In this study, fast centrifugal partition chromatography (FCPC) was used coupled with in vitro tests on HT-29 cells as a screening procedure to identify apoptotic saponins from an acetonic extract of concentrated agave sap. The three most bioactive fractions obtained by FCPC at partition coefficients between 0.23 and 0.4 contained steroidal saponins, predominantly magueyoside b. Flow cytometry analysis determined that the fraction rich in kammogenin and manogenin glycosides induced apoptosis, but when gentrogenin and hecogenin glycosides were also found in the fraction, a necrotic effect was observed. In conclusion, this study provides the evidence that steroidal saponins in concentrated agave sap were potential inductors of apoptosis and that it was possible to separate them using fast centrifugal partition chromatography.

Two new dammarane-type triterpene sapogenins from Chinese red ginseng.

Two new dammarane-type triterpene sapogenins were isolated from the Chinese red ginseng. The new sapogenins were named as 24,26-dihydroxy-panaxdiol (1) and 24-hydroxy-panaxdiol (2). Their structures were elucidated by the combined analysis of NMR and mass spectrometry as 20(S),25(R)-epoxydammarane-3ß,12ß,24ß,26-tetraol (1) and 20(S),25-epoxydammarane-3ß,12ß,24α-triol (2). The complete signal assignments of the two compounds were carried out by 2D NMR spectral and NOE differential spectroscopy analysis.

Ginseng Saponins in Different Parts of Panax vietnamensis.

Chemical and pharmacological studies of Panax vietnamensis (Vietnamese ginseng; VG) have been reported since its discovery in 1973. However, the content of each saponin in different parts of VG has not been reported. In this study, 17 ginsenosides in the different underground parts of P. vietnamensis were analyzed by HPLC/evaporative light scattering detector (ELSD). Their contents in the dried rhizome, radix, and fine roots were 195, 156, and 139 mg/g, respectively, which were extremely high compared to other Panax species. The content of protopanaxatriol (PPT)-type saponins were not much different among underground parts; however, the content of protopanaxadiol (PPD)- and ocotillol (OCT)-type saponins were greatly different. It is noteworthy that the ginsenoside pattern in the fine roots is different from other underground parts. In particular, despite the content of PPD-type saponins being the highest in the fine roots, which is similar to other Panax species, the total content of saponins was the lowest in the fine roots, which is different from other Panax species. The ratios of PPT : PPD : OCT-type saponins were 1 : 1.7 : 7.8, 1 : 1.6 : 5.5, and 1 : 4.8 : 3.3 for the rhizome, radix, and fine roots, respectively. OCT-type saponins accounted for 36-75% of total saponins and contributed mostly to the difference in the total saponin content of each part.

Saponins, Esculeosides B-1 and B-2, in Tomato Juice and Sapogenol, Esculeogenin B1.

It has been shown that commercial tomato juice packaged in 900 g plastic bottles contains rare, naturally occurring steroidal solanocapsine-type tomato glycosides in which the saponins consist of esculeosides B-1 (2) and B-2 (3) in 0.041% as major components lacking esculeoside A. We suggest that these saponins are derived from esculeoside A (1) when the juice in plastic bottles is prepared by treatment with boiling water, similar to the process used in preparing canned tomatoes. Herein, the obtained tomato saponins (2) and (3) provided sapogenols esculeogenin B1 (4) and B2 (5), respectively, by acid hydrolysis. The former was identical to esculeogenin B previously reported, and the latter was a new sapogenol characterized to be (5α,22S,23S,25S)-22,26-epimino-16ß,23-epoxy-3ß,23,27-trihydroxycholestane.

Metabolic profiles of 20(S)-protopanaxadiol in rats after oral administration using ultra-performance liquid chromatography/quadrupole time-of-flight tandem mass spectrometry.

RATIONALE: 20(S)-Protopanaxadiol (PPD), a dammarane-type triterpenoid sapogenin, acts as the pharmacophore of ginsenosides which are considered as the principal bioactive components in Chinese ginseng. To fully understand the mechanism of action of PPD, it is important to study its metabolic profiles in vivo. METHODS: Plasma, urine, fece and bile were collected after administration of PPD formulated in 0.5% aqueous Tween-80 to rats (150 mg/kg). Samples were analyzed by using a sensitive and reliable method based on ultra-performance liquid chromatography/quadrupole time-of-flight tandem mass spectrometry (UPLC/Q-TOF-MS/MS) in both positive and negative ion mode. The chemical structures of metabolites were elucidated by comparing the retention time, accurate molecular mass, and fragmentation patterns of analytes with those of PPD. RESULTS: In total 29 metabolites, including 10 new metabolites (M20-M29), were tentatively identified and characterized. Among them, two metabolites (M3 and M4) were unambiguously identified by matching their retention times and fragmentation patterns with their standards. Principal metabolites, namely, 20, 24-oxide metabolites (M3 and M4), 26/27-carboxylic acid derivatives (M22 and M23) and a glucuronidated product (M28), were found in the rat plasma. CONCLUSIONS: The results showed that phase I metabolites are monooxygenation, dioxygenation and oxidative dehydrogenation metabolites, and phase II metabolic pathways were demonstrated to be cysteine conjugation and glucuronidation. The newly identified metabolites are useful to understand the mechanism of elimination of PPD and, in turn, its effectiveness and toxicity.

Characterization of metabolites of 20(S)-protopanaxadiol in rats using ultra-performance liquid chromatography/quadrupole-time-of-flight mass spectrometry.

In this study, ultra-performance liquid chromatography (UPLC)/quadrupole-time-of-flight mass spectrometry (QTOF-MS) was applied to the rapid analysis of 20(S)-protopanaxadiol (PPD) metabolites in rats after oral administration, enabling the structural characterization of 23 metabolites in plasma, bile, urine, and feces. 16 of these, including M1-M5, M9, and M11-M15, have not been previously reported. The results also indicated that demethylation, dehydration, dehydrogenation, oxidation, deoxidation, and glucuronidation were the major metabolic reactions of PPD in vivo. This study provides important information about the metabolism of PPD which will be helpful for fully understanding its mechanism of action. Furthermore, structural modification of PPD in vivo may aid in obtaining new chemical derivatives for pharmacological screening.

Glaucogenin E, a new C21 steroid from Cynanchum stauntonii.

Glaucogenin E (1), a new C(21) steroid sapogenin, along with three known ones (2-4) were isolated from the rhizomes of Cynanchum stauntonii (Decne.) Schltr. ex Levl. Their structures were established mainly by the spectroscopic analysis, including 2D NMR. All the isolated compounds were evaluated for their cytotoxicity against human cancer cell lines HeLa, Bel-7402, SGC-7901 and BGC-823.