Development and validation of an UHPLC–MS/MS approach for simultaneous quantification of five bioactive saponins in rat plasma: Application to a comparative pharmacokinetic study of aqueous extracts of raw and salt-processed Achyranthes bidentata

Chemical Profiling of Shen-Wu-Yi-Shen Tablets Using UPLC-Q-TOF-MS/MS and Its Quality Evaluation Based on UPLC-DAD Combined with Multivariate Statistical Analysis

Shen-Wu-Yi-Shen tablets (SWYST) is a traditional Chinese medicine prescription used for treating chronic kidney disease (CKD). This study aims to characterize the constituents in SWYST and evaluate the quality based on the quantification of multiple bioactive components. SWYST samples were analyzed with ultra-high-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) and a data-processing strategy. As a result, 215 compounds in SWYST were unambiguously identified or tentatively characterized, including 14 potential new compounds. Meanwhile, strategies based on characteristic fragments for rapid identification were summarized, indicating that the qualitative method is accurate and feasible. Notably, the glucose esters of laccaic acid D-type anthraquinone were first found and their fragmentation patterns were described by comparing that of O-glycoside isomers. Besides, based on comparisons of the cleavage ways of mono-acyl glucose with different acyl groups or acylation sites, differences in fragmentation pathways between 1,2-di-O-acyl glucose and 1,6-di-O-acyl glucose were proposed for the first time and verified by reference substances. In addition, a validated UPLC-DAD was established for the determination of 11 major bioactive components related to treatment of CKD (albiflorin, paeoniflorin, 2,3,5,4'-tetrahydroxy-stilbene-2-O-β-d-glucoside (TSG), 1-O-galloyl-2-O-cinnamoyl-β-d-glucose, emodin-8-O-β-d-glucoside, chrysophanol-O-β-d-glucoside, aloe-emodin, rhein, emodin, chrysophanol and physcion). Moreover, TSG and 1-O-galloyl-2-O-cinnamoyl-β-d-glucose were found as the quality markers related to the origins of SWYST based on multivariate statistical analysis. Conclusively, the findings in this work provide a feasible reference for further studies on quality research and mechanisms of action in treating CKD.

Characterization of the Components and Metabolites of Achyranthes Bidentata in the Plasma and Brain Tissue of Rats Based on Ultrahigh Performance Liquid Chromatography-High-Resolution Mass Spectrometry (UHPLC-HR-MS)

BACKGROUND

Achyranthes bidentata (AR) is a traditional Chinese herb used for the treatment of hypertension and cerebral ischemia, but its pharmacological effects are not known.

AIM OF STUDY

We aimed to detect and accurately identify the components and metabolites of AR in the plasma and brain tissue of Sprague Dawley rats.

METHODS

We employed ultrahigh performance liquid chromatography-high-resolution mass spectrometry (UHPLC-HR-MS) to detect AR components in the plasma and brain tissue of rats. The absorption and metabolites in the plasma and brain tissue of normal control rats and rats that underwent middle cerebral artery occlusion (MCAO) were characterized and compared.

RESULTS

A total of 281 compounds, including alkaloids, flavonoids, terpenoids, phenylpropanes, sugars and glycosides, steroids, triterpenes, amino acids, and peptides, was identified in samples of Achyranthes bidentata (TCM-AR). Four types of absorbable prototype components and 48 kinds of metabolites were identified in rats in the normal control plasma group which were given AR (AR plasma group), and five kinds of metabolites were identified in rats of the normal control brain tissue group which were given AR (AR brain group). Three absorbed prototype components and 13 metabolites were identified in the plasma of rats which underwent MCAO and were given AR (MCAO + AR plasma group). Six absorbed prototype components and two metabolites were identified in the brain tissue of rats who underwent MCAO and were administered AR (MCAO + AR brain group). These results showed that, after the oral administration of AR, the number of identified components in plasma was more than that in brain tissue. The number of prototype components in the AR plasma group was higher than that in the MCAO + AR plasma group, which may indicate that metabolite absorption in rats undergoing MCAO was worse. The number of prototype components in the MCAO + AR brain group was higher than that in the AR brain group, indicating that the blood-brain barrier was destroyed after MCAO, resulting in more compounds entering brain tissue.

CONCLUSIONS

UHPLC-HR-MS was used to rapidly analyze the components and metabolites of AR in the blood and brain of rats under normal and pathologic conditions, and to comprehensively characterize the components of TCM-AR. We also analyzed and compared the absorbable components and metabolites of normal rats under cerebral ischemia-reperfusion injury to explore the potential mechanism of action. This method could be applied to various Chinese herbs and disease models, which could promote TCM modernization.

Comprehensive metabolic profiles of Achyranthes bidentate in rat serum via ultra-high performance liquid chromatography time-of-flight mass spectrometry and their correlation with osteoinductive activity

The osteoinductive effect of crude and salt-processed Achyranthes bidentata is associated with the serum metabolites. Grey relationship analysis between the serum metabolites and osteoinductive effect will help to clarify the bioactive serum metabolites. First, an ultra-high performance liquid chromatography time-of-flight mass spectrometry method was used to develop serum metabolic fingerprint of rats after oral administration of crude and salt-processed Achyranthes bidentata. The MS¹ and MS² data of serum metabolites were scanned in the range of m/z 100-1500 and 50-1200, respectively. The chemical structures of the metabolites were thoroughly elucidated. Two prototypes and twelve metabolites have been identified. Second, osteoblasts were cultured with the drug-containing serum at different time points. The osteoinductive effect of crude and salt-processed Achyranthes bidentata was evaluated by detecting the proliferation rate and alkaline phosphatase activity of osteoblasts. Third, grey correlation analysis was utilized to elucidate the spectral-effect relationship between serum metabolic fingerprints and osteoinductive effect. Finally, the correlation coefficients of ten metabolites, i.e., oleanolic acid, poststerone-M1, chikusetsusaponin V-M1, oleanolic acid-M2, oleanolic acid-M4, spinacoside D-M1, chikusetsusaponin I-M1, betavulgaroside IV-M2, chikusetsusaponin IVa and achyranthoside IV-M1 were above 0.7. Collectively, our work will provide helpful knowledge for the future research on Achyranthes bidentata.

Salt processing: A unique and classic technology for Chinese medicine processing

Traditional Chinese medicine (TCM) processing is the summary of long-term clinical experience, processing can change the property, taste and meridian of TCM, achieve the purpose of reducing toxicity and increasing efficiency, to ensure the safety of clinical medication. This paper summarizes the research advance of salt processing in recent years from the aspects of the types of excipients, salt processing methods, salt processing purpose and the influence of salt process on the chemical composition, pharmacodynamic effect and in vivo behavior of TCM, and analyzes and discusses the shortcomings of the current research, so as to provide ideas for the further research and development of salt processing of TCM. The literatures were classified and summarized by consulting the scientific database (such as SciFinder Scholar, CNKI, Google Scholar, Baidu Scholar, etc.), Chinese herbal classics and Chinese Pharmacopoeia and so on. The results show that salt processing is helpful to introduce drugs into the kidney channel and enhance the effect of nourishing Yin and falling fire. The pharmacological effect, chemical composition and in vivo behavior of TCM will change after salt processing. In the future, we should strengthen the research on standardizing the dosage of excipients, the quality standard after processing, the relationship between the change of chemical composition after salt processing and the enhancement of pharmacological efficacy, so as to deeply explain the principle of salt processing, and further improve and optimize the salt making process. By combing the influence of the of salt processing of TCM and analyzed the current problems, we hope to provide guidance for the in-depth study of the salt processing mechanism of TCM and the inheritance and innovation of TCM processing technology.

Optimized ultra-high-performance liquid chromatography tandem mass spectrometry method for detecting compositional changes in Eucommia ulmoides and Achyranthes bidentata paired decoctions in vitro and in vivo

Rationale

The bark of Eucommia ulmoides and the roots of Achyranthes bidentata are commonly used in traditional Chinese medicine, and their pairing appears in many traditional Chinese medicine formulas as a recognized compatible unit. However, the changes and interactions of the main components of these two formulas when paired remain unclear, and there is currently no standard or method for their quality control and assessment of pharmacological effects.

Methods

An optimized ultra-high-performance liquid chromatography triple-quadrupole mass spectrometry (UHPLC-MS/MS) method was established for the simultaneous identification of 10 components in E. ulmoides and A. bidentata using in vitro and in vivo models. Tributyltin methacrylate was the internal standard solution, and the blood samples were treated by an organic solvent precipitation method. Gradient elution was conducted on a C18 column at 25 °C with 0.1% formic acid water:acetonitrile as the mobile phase at a flow rate of 0.5 mL min−1. Dynamic multiple response monitoring was performed in negative-ion mode using an Agilent Jet Stream electrospray ionization ion source.

Results

In negative-ion detection mode, eucommiol exhibited a good response, and the isomers ginsenoside Ro and achyranthoside C could also be well separated. The developed method accurately detected the five components with a low blood content. Compared to controls, the levels of ginsenoside Ro, chikusetsusaponin Ⅳa, and achyranthoside C increased; the contents of geniposidic acid and pinoresinol diglucoside were unchanged; and the levels of eucommiol, geniposide, β-ecdysterone, genipin, and achyranthoside D decreased in vitro. In vivo, the contents of geniposidic acid, geniposide, pinoresinol diglucoside, and β-ecdysterone were reduced; the contents of eucommiol and ginsenoside Ro were unchanged; and those of achyranthoside D, chikusetsusaponin Ⅳa, and achyranthoside C increased compared to the corresponding levels in the internal control.

Conclusions

A method for the quality control of the E. ulmoides-A. bidentata drug pair was established for the first time and the main components in 10 drug pairs could be determined simultaneously in vitro and in vivo. These findings show that the E. ulmoides and A. bidentata drug pair cause a compositional change, providing new ideas for the development of this combination to improve clinical efficacy.

A Multi-Omics Analysis Reveals Anti-Osteoporosis Mechanism of Four Components from Crude and Salt-Processed Achyranthes bidentata Blume in Ovariectomized Rats

The root of Achyranthes bidentata Blume (AB) is a well-known traditional Chinese medicine for treating osteoporosis. Plenty of studies focused on the pharmacological mechanism of the whole extract; however, the contribution of different components to the anti-osteoporosis effect remains unknown. The aim of this study is to explore the anti-osteoporosis mechanism of different components of crude and salt-processed AB under the guidance of network pharmacology, metabolomics, and microbiomics. First, network pharmacology analysis was applied to constructing the compound-target-disease network of AB to provide a holistic view. Second, the anti-osteoporosis effects of the four components were evaluated in female Wistar rats. The subjects were divided into a normal group, a model group, a 17α-estradiol (E2)-treated group, a polysaccharide-component-treated groups, and a polysaccharide-knockout-component-treated groups. All the serum, urine, and feces samples of the six groups were collected after 16 weeks of treatment. Biochemical and microcomputed tomography (μCT) parameters were also acquired. Coupled with orthogonal partial least-squares discrimination analysis, one dimensional nuclear magnetic resonance (NMR) was used to monitor serum metabolic alterations. A total of twenty-two biomarkers, including lipids, amino acids, polyunsaturated fatty acids, glucose, and so on were identified for the different components-treated groups. Through pathway analysis, it is indicated that glyoxylate and dicarboxylate metabolism, glycine, serine, and threonine metabolism, alanine, aspartate, and glutamate metabolism, d-glutamine, and d-glutamate metabolism were the major intervened pathways. Levels of these biomarkers shifted away from the model group and were restored to normal after treatment with the four components. In addition, 16S rDNA sequencing demonstrated that the abundance of Anaerofilum, Rothia, and Turicibacter bacteria was positively correlated with an anti-osteoporosis effect, whereas the abundance of Oscillospira was negatively correlated. The osteoprotective effect of the polysaccharide components of crude and salt-processed AB is related to the regulation of the abundance of these gut microbiota.

Global identification and quantitative analysis of representative components of Xin-Nao-Kang Capsule, a traditional Chinese medicinal formula, by UHPLC-Q-TOF-MS and UHPLC-TQ-MS

Xin-Nao-Kang Capsule (XNKC), a well-known traditional Chinese medicine (TCM), is widely used for the treatment of angina pectoris, cerebral arteriosclerosis and coronary artery disease in China. However, the chemical components have not been holistically explored. In this study, a total of 173 chemical components including 48 flavonoids, 8 lactones, 35 acids, 12 phenanthraquinones, 8 monoterpene glycosides, 32 triterpenoids and 30 other compounds were identified, among which 37 were unambiguously characterized in comparison with their corresponding authentic standards using ultra-high performance liquid chromatography coupled with quadruple time-of-flight tandem mass spectrometry (UHPLC-Q-TOF-MS). To further elucidate the major representative constitutes of XNKC, a high performance liquid chromatography coupled with triple quadrupole tandem mass spectrometry (UHPLC-TQ-MS) method was used for simultaneous quantitative analysis of 34 major representative constitutes in ten batches of XNKC samples, which was validated in terms of linearity, precision, accuracy, repeatability and recovery. Meanwhile, the results of chemometric analysis indicated that puerarin and salvianolic acid B might be the most potential quantitative markers for quality control of XNKC. Taken together, the chemical constitutes of XNKC were systematically identified and a reliable quantitative method coupled with chemometric analysis was successfully employed for evaluating the holistic quality of XNKC. This study will provide a robust foundation for the holistic quality assessment of XNKC.

Exploration of the mechanism of Zisheng Shenqi decoction against gout arthritis using network pharmacology

BACKGROUND

In this study, the network pharmacological methods were used to predict the target of effective components of compounds in Zisheng Shenqi Decoction (ZSD, or Nourishing Kidney Qi Decoction) in the treatment of gouty arthritis (GA).

METHOD

The main effective components and corresponding key targets of herbs in the ZSD were discerned through the Traditional Chinese Medicine Systems Pharmacology Database and Analysis (TCMSP), Bioinformatics Analysis Tool for Molecular mechanism of Traditional Chinese Medicine (BATMAN-TCM) database. UniProt database and Swiss Target Prediction (STP) database was used to rectify and unify the target names and supply the target information. The targets related to GA were obtained by using GeneCards database. After we discovered the potential common targets between ZSD and GA, the interaction network diagram of "ZSD-component-GA-target" was constructed by Cytoscape software (Version 3.7.1). Subsequently, the Protein-protein interaction (PPI) network of ZSD effective components-targets and GA-related targets was constructed by Search Tool for the Retrieval of Interacting Genes Database (STRING). Bioconductor package "org.Hs.eg.db" and "cluster profiler" package were installed in R software (Version 3.6.0) which used for Gene Ontology analysis and KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway enrichment analysis.

RESULTS

146 components and 613 targets of 11 herbal medicines in the ZSD were got from TCMSP database and BATMAN-TCM database. 987 targets of GA were obtained from GeneCards database. After intersected and removed duplications, 132 common targets between ZSD and GA were screened out by Cytoscape software (Version 3.7.1). These common targets derived from 81 effective components of 146 components, such as quercetin, stigmasterol and kaempferol. They were closely related to anti-inflammatory, analgesic and anti oxidative stress and the principal targets comprised of Purinergic receptor P2X, ligand-gated ion channel 7 (P2x7R), Nod-like receptor protein 3 (NLRP3) and IL-1β. GO enrichment analysis and KEGG pathway enrichment analysis by R software (Version 3.6.0) showed that the key target genes had close relationship with oxidative stress, reactive oxygen species (ROS) metabolic process and leukocyte migration in aspects of biological process, cell components and molecular function. It also indicated that ZSD could decrease inflammatory reaction, alleviate ROS accumulation and attenuate pain by regulating P2 × 7R and NOD like receptor signaling pathway of inflammatory reaction.

CONCLUSION

A total of 81 effective components and 132 common target genes between ZSD and GA were screened by network pharmacology. The PPI network, GO enrichment analysis and KEGG pathway enrichment analysis suggested that ZSD can exerte anti-inflammatory and analgesic effects on the treatment of GA by reducing decreasing inflammatory reaction, alleviating ROS accumulation, and attenuating pain. The possible molecular mechanism of it mainly involved multiple components, multiple targets and multiple signaling pathways, which provided a comprehensive understanding for further study. In general, the network pharmacological method applied in this study provides an alternative strategy for the mechanism of ZSD in the treatment of GA.

Raw and salt-processed Achyranthes bidentata attenuate LPS-induced acute kidney injury by inhibiting ROS and apoptosis via an estrogen-like pathway

BACKGROUND

Traditional Chinese medicine suggests that Radix Achyranthis Bidentatae nourishes and protects the kidneys, the effect of which is enhanced following a salt treatment. Raw and salt-processed Achyranthes bidentata are produced via different processing techniques from the same crude Achyranthes root. The anti-inflammatory and immunomodulatory properties of this plant have been verified earlier. However, there is a scarcity of experimental evidence for the renal-protective effects.

AIM

The purpose of present study is to compare the protective effects of raw and salt-processed Achyranthes on lipopolysaccharide (LPS) - induced acute kidney injury in mice and chemically characterize their extracts.

METHOD

The monomer components of raw and salt-processed Achyranthes extracts were analyzed using high performance liquid chromatography (HPLC). The aggregation and distribution of 2-Deoxy-D-glucose (2-DG) near infrared fluorescence probe in mice was examined with a small animal imaging systems. The pathological and morphological changes of kidneys were observed by H&E staining, and the serum urea nitrogen (BUN) and serum creatinine (Scr) levels were used to evaluate the renal function. The levels of cytokines in serum were detected by cytometric bead array. Flow cytometry assay was performed to assess the apoptosis and reactive oxygen species (ROS) in the kidney cells, and cell surface marker expression including CD45⁺, F4/80⁺, and Ly-6G⁺. The estrogenic activities of the raw and salt-processed Achyranthes were observed by uterine weight gain test in sexually immature mice. Western blot was used to detect the protein expression levels in the kidney.

RESULTS

Chemical analysis showed that the salt-processed Achyranthes contained more ginsenoside Ro and chikusetsusaponin Ⅳa than the raw Achyranthes, but there was no difference in the contents of β-ecdysterone, 25R-inokosterone, and 25S-inokosterone.in vivo near-infrared fluorescence imaging showed a significant reduced inflammation in the AKI mice. Histological studies showed that the raw and salt-processed Achyranthes markedly decreased the inflammatory infiltration, swelling and vacuolar degeneration in renal tissues and the Scr and BUN. Importantly, the raw and salt-processed Achyranthes extracts demonstrated different degrees of inhibition on the LPS-induced AKI, with salt-processed Achyranthes showing better inhibition. Results of flow cytometry showed a significant inhibition of IFN-γ, TNF-α, and IL-2, and promoted IL-10, along with reduced macrophages (CD45 + F4/80+), neutrophils (CD45+ Ly-6G+) and phagocytes. Furthermore, the extracts reduced the accumulation of ROS and apoptosis in the kidney, and also regulated the expression of apoptosis marker proteins TLR4, Bcl-2, Bax, cleaved caspase 3 and cleaved caspase 9 levels. Notably, they increased ERα, ERβ, and GPR30 in the renal tissues of AKI mice and LPS non-treated mice. In the subsequent experiments, it was found that the raw and salt-processed Achyranthes extracts increased the uterine coefficient in sexually immature mice, improved the LPS-induced decrease in NRK52e cell viability, and reduced the apoptosis, which could be antagonized by ICI182, 780 (estrogen receptor-unspecific antagonist, Faslodex).

CONCLUSIONS

The renal-protective effect of raw and salt-processed Achyranthes was exhibited through antiapoptotic and antioxidant mechanisms via an estrogen-like pathway, along with a modulation of the inflammatory response by regulating immune cells. Ginsenoside Ro and Chikusetsu saponin IVa were found to be the key factors to enhance the protective effect of salt-processed Achyranthes.

Simultaneous Quantitation of Five Bioactive Ingredients in Raw and Processed Fallopia multiflora by Employing UHPLC-Q-TOF-MS

Fallopia multiflora is used for treatment of premature graying hair and blood deficiency. In this study, a quantitative method was developed for determination of five bioactive components (emodin, 2,3,5,4′-tetrahydroxy-stilbene- 2-Ο-β-d-glucoside, emodin-8-O-β-d-glucopyranoside, ω-hydroxyemodin and kaempferol) in raw and processed F. multiflora by using ultra-high performance liquid chromatography (UHPLC)-quadrupole time-of-flight mass spectrometry-based method. The sample handling procedure was optimized. Chromatographic separation was carried out on a Thermo Syncronis AQ-C18 UHPLC column with mobile phase consisting of 0.01% aqueous formic acid and acetonitrile. The method was interrogated in terms of linearity, precision, stability and recovery tests. All calibration curves displayed good linearity (R2 > 0.9992). The limit of detection and limit of quantification of these components ranged from 0.01 to 0.03 μg/mL and from 0.03 to 0.07 μg/mL, respectively. The average recoveries of these components were from 98.2 to 102.9% with relative standard deviation values from 0.8 to 2.9% for F. multiflora. The developed method can be applied to quality control of raw and processed F. multiflora.

Integrated metallomic and metabolomic profiling of plasma and tissues provides deep insights into the protective effect of raw and salt-processed Achyranthes bidentata Blume extract in ovariectomia rats

ETHNOPHARMACOLOGICAL RELEVANCE

Achyranthes bidentata Blume (AB) is a well-known traditional Chinese medicine for treating osteoporosis and bone fracture. In the current, researches on pharmacological mechanism of AB mostly focused on molecular pathways, knowledge about its metabolic signatures is largely unclear. This study aims to develop an integrative metabolomics and metallomic approach for deciphering the biochemical basis of anti-osteoporosis effects of raw and salt-processed AB.

METHOD

Gas chromatography-mass spectrometry (GC-MS) and inductively coupled plasma mass spectrometry (ICP-MS) were combined for metabolomic and metallomic profiling of rats serum, liver and kidney derived from the sham group, model group, E2, raw and salt-processed AB treated groups. Meanwhile, micro-CT and biomechanical analysis were carried out to ensure the success of the osteoporosis model and to validate the anti-osteoporosis effect of raw and salt-processed AB. Partial least squares discriminant analysis (PLS-DA) was employed to screen potential biomarkers and the MetaboAnalyst and KEGG PATHWAY Database were used to investigate the metabolic pathway.

RESULTS

Raw and salt-processed AB protected the rats against osteoporosis, as evidenced by the restoration of the alkaline phosphatase activity, osteocalcin concentration, urine calcium/creatinine ratio and urine phosphorus/creatinine ratio. The combination of PCA and PLS-DA revealed deviations in ninety-four differential biomarkers between raw AB treated group and model group. The identified biomarkers were primarily engaged in the metabolic pathways including galactose metabolism, urea cycle, arginine and proline metabolism, alanine metabolism, lactose degradation, ammonia recycling and glycine and serine metabolism. The levels of these biomarkers showed significant alterations and a tendency to be restored to normal values in raw and salt-processed AB treated osteoporosis rats. Of note, the levels of trace elements, such as Zn, Se, Mn, Cu and Fe, were elevated after raw and salt-processed AB treatment. Finally, a correlation network diagram was constructed to show the biomarkers perturbed by raw and salt-processed AB.

CONCLUSION

Our findings indicate that raw and salt-processed AB has positive effects on osteoporosis rats. Meanwhile, metabolomic and metallomic method coupled with metabolites enrichment analysis and pattern recognition serves as a useful tool for revealing the action mechanism of traditional Chinese medicine.

Influence Factors of the Pharmacokinetics of Herbal Resourced Compounds in Clinical Practice

Herbal medicines have been used to prevent and cure diseases in eastern countries for thousands of years. In recent decades, these phytotherapies are becoming more and more popular in the West. As being nature-derived is the essential attribute of herbal medicines, people believe that taking them for diseases treatment is safe enough and has no side-effects. However, the efficacy of herbal resourced compounds (HRC) depends on the multiple constituents absorbed in the body and their pharmacokinetics. Thus, many factors will influence the clinical practice of HRC, i.e., their absorption, distribution, metabolism, and excretion (ADME). Among these factors, herb-drug interaction has been widely discussed, as these compounds may share the same drug-metabolizing enzymes and drug transporters. Meanwhile there are many other potential factors that can also change the ADME of HRC, including herb pretreatment, herb-herb interactions, pathological status, gender, age of patient, and chemical and physical modification of certain ingredients. With the aim of ensuring the efficacy of HRC and minimizing their clinical risks, this review provides and discusses the influence factors and artificial improvement of the pharmacokinetics of HRC.

Oleanane-Type Saponins Biosynthesis in Panax notoginseng via Transformation of β-Amyrin Synthase Gene from Panax japonicus

Oleanane-type saponins considered as the main medicinal ingredients in Panax japonicus are not found in Panax notoginseng. β-Amyrin synthase (βAS) was recognized as the first key enzyme in the biosynthetic branch of oleanane-type saponins. In this study, βAS gene from P. japonicus ( PjβAS) was transferred into P. notoginseng cells. Along with PjβAS expression in the transgenic cells, the expression levels of several key enzyme genes related to triterpenoid saponins biosynthesis and the content of P. notoginseng saponins were also increased. Two oleanane-type saponins, chikusetsusaponin IV and chikusetsusaponin IVa, contained in P. japonicus were first discovered in transgenic P. notoginseng cells. This study successfully constructed a biosynthetic pathway of oleanane-type saponins in P. notoginseng by introducing just one gene into the species. On the basis of this discovery and previous studies, the common biosynthetic pathway of triterpenoid saponins in Panax genus may be unified to some extent.

A liquid chromatography-tandem mass spectrometry approach for study the tissue distributions of five components of crude and salt-processed Radix Achyranthes in rats

This study developed a robust and reliable approach using liquid chromatography- tandem mass spectrometry for the simultaneous determination of five saponins in rat tissues: β-ecdysterone, chikusetsusaponin IV, ginsenoside Ro, 25S-inokosterone and chikusetsusaponin IVa. This is the first report on a comparative tissue distribution study of crude and salt-processed Radix Achyranthes in rats. After one-step protein precipitation by acetonitrile, the tissue samples were sent to LC-MS/MS for multiple reaction monitoring. The retention times of the five saponins and internal standard were 1.77, 3.14, 3.01, 1.83, 3.26 and 4.77 min. The standard curves showed good linear regression (r²  > 0.9991) in the range of 10.3-1562.5 ng/mL. The intra- and inter-day accuracy and precision were within 15% of the nominal concentration. The recoveries of the five saponins were 92.0-99.9%. Finally, this approach was successfully applied to tissue distribution analysis of the five saponins after oral administration of crude and salt-processed Radix Achyranthes in rats. The largest concentration of the five saponins was observed in kidney after salt-processing, which indicated that processing could enhance the bioavailability.