Simultaneous determination of six isoflavonoids in commercial Radix Astragali by HPLC-UV

Investigation of facile spectroscopic approaches for rapid calycosin determination in invitro biological samples and pharmaceuticals; application to the content uniformity of capsules

Calycosin, the major bioactive isoflavonoid inAstragali Radix and an important anti-viral drug with a variety of pharmacological actions, is being determined by five different spectroscopic methods. Two spectrophotometric methods have been investigated including measuring the absorption spectra at λ^max = 270 nm and the first derivative spectra at λ = 288 nm for methods I and II, respectively. For the first time; the native fluorescence of calycosin is measured without adding any reagents. The fluorescence intensity was measured at 340 nm after excitation at 282 nm in method III. The fourth method involves the direct measuring of a first derivative spectrofluorimetric emission peak at 292 nm. In method V synchronous fluorescence spectra were recorded in methanol at Δλ = 70 nm. The linear range for the fluorescence-based methods was 0.05-1.0 µg/mL and for the UV-based methods was 0.5-10.0 µg/mL. The methods were validated per International Council of Harmonization (ICHQ2R1) guidelines. The limits of detection were found to be down to 0.11 and 0.12 µg/mL for the spectrophotometric methods, and 15.0, 18.0,16.0 ng/ mL, for the spectrofluorimetric approaches respectively, representing the high sensitivity. Accordingly, this permitted the quantitation of calycosin in spiked human plasma samples with satisfactory percentage recoveries (94.50.-102.50 %). The methods were utilized for calycosin analysis in different matrices including plasma and capsules with high precision and accuracy.

Exposure assessment and risk-based limit levels evaluation of ochratoxin A in Astragali Radix in China

Ochratoxin A (OTA) is a mycotoxin found in a variety of foods and herbal medicines, and several governmental bodies around the world have set maximum allowable levels of OTA in different foods and herbal medicines. This study aims to evaluate the health risk of OTA in Astragali Radix (AR) in China, and to evaluate the effects of different limit levels on the risk control of OTA in AR. The concentrations of OTA in 187 samples of AR were investigated, and 61 (32.6%) samples were positive. The mean, 50th and 95th percentile values of OTA in positive samples were 56.2, 5.1 and 304.5 μg/kg, respectively. A margin of exposure (MOE) approach was applied to assess the risk. Considering other food sources, long-term consumers have a relatively high risk of OTA exposure due to the ingestion of AR. Theoretical limit levels of OTA in AR were evaluated from two dimensions by weighing the costs and the benefits. The results indicated that the limit levels that might be applied to the management of OTA contamination in AR in China could be screened out through risk-based evaluation of limit levels.

Nutritional Characterization and Untargeted Metabolomics of Oyster Mushroom Produced Using Astragalus membranaceus var. mongolicus Stems and Leaves as Substrates

Astragalus membranaceus var. mongolicus (AMM) is an edible and medicinal material and is commonly used in East Asia. According to the pharmacopeia of China, the dried root of AMM is medicinal. However, the aerial parts of AMM are always directly discarded after harvest. The stems and leaves are also rich in active compounds, including saponins, flavonoids, terpenoids, and polysaccharides. To rationally use resources, waste products from AMM stems and leaves are useful substrates for edible fungus cultivation. Here, oyster mushroom (Pleurotus ostreatus var. florida) was cultivated on a basal substrate supplemented with AMM stems and leaves (AMM group). The nutritional and chemical composition of the fruiting body were analyzed by metabolomics and chemometrics. Our results showed that AMM addition to the substrate affected the fresh weight, moisture, fat, protein, and element concentrations, and amino acid composition of oyster mushroom. Moreover, 2,156 metabolites were detected and annotated based on the metabolomics data, of which 680 were identified as differentially expressed metabolites. Many active phytometabolites previously identified in AMM herbs were also detected in the metabolomics of oyster mushroom from AMM group, including 46 terpenoids, 21 flavonoids, 17 alkaloids, 14 phenylpropanoids, and 3 fatty acids. In summary, our results imply that oyster mushroom cultured with AMM stems and leaves might have very high nutritional therapy health care value.

Quantification by LC-MS/MS of astragaloside IV and isoflavones in Astragali radix can be more accurate by using standard addition

INTRODUCTION

Astragali radix (AR), the root of Astragalus, is an important medical herb widely used in traditional Chinese medicine. Bioactive components include isoflavones and a unique class of triterpenoid saponins (named astragalosides).

OBJECTIVES

Accurate measurement of bioactive components, especially astragaloside IV, is necessary for confirming AR authenticity, quality control and future medical research.

METHODOLOGY

Liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) is a suitable technique but suffers from ion suppression effects due to sample matrix. This can be corrected by using isotopic labelled internal standards, but these are not available for many phytochemicals. We explored the use of standard addition to circumvent this issue.

RESULTS

LC-MS/MS and liquid chromatography coupled with ultraviolet (LC-UV) detection provided linear calibration curves (R² > 0.99). LC-MS/MS provided superior selectivity and detection limits below 10 ng/mL, which was 2-3 magnitudes lower than LC-UV detection. Precision and accuracy were overall improved by using LC-MS/MS with diluted sample extracts, resulting in an inter series coefficient of variation (CV) of 12% or less and mean recovery estimates in the 85-115% range. LC-MS/MS quantification by standard addition resulted in significantly higher concentrations of astragaloside IV measured in the samples. Concentrations calculated by standard addition were unaffected by large variation in signal response caused by matrix effects, independent of variation in slope of the standard addition curves.

CONCLUSION

Sample dilution was helpful but not sufficient for reducing effects of ion suppression. We have shown that LC-MS/MS quantification by standard addition can be a powerful approach for accurate measurement of phytochemicals in the absence of isotopic labelled internal standards.

An integrated strategy for evaluation of sulfur-fumigated edible herb Astragali Radix based on UPLC-MS/MS platforms and pharmacological analysis

Astragali Radix is an edible herb that has been employed in Traditional Chinese medicine (TCM) and has recently been recognized by various countries; however, it is also one of the most extensively sulfur-fumigated TCM components. This study designed a UPLC-QTOF-MS/MS-guided isolation approach to generate sulfur-containing derivatives, and a novel sulfur-containing marker, namely, astragaloside sulfate, was characterized based on 1D and 2D NMR, which were derived from the main component of Astragali Radix, namely, astragaloside. Pharmacological experiments also showed that the activity of astragaloside decreased after it was converted into sulfate. Moreover, a rapid assay for the determination of astragaloside sulfate content by UPLC-QTRAP-MS/MS was established to evaluate samples that were non-fumigated and sulfur-fumigated at different levels. The method was applied to determine the content of JGS in the different batches of commercial samples. This research reveals that the practical procedure-based typical sulfur-containing indicator can be utilized for quality assurance of sulfur-fumigated and non-fumigated Astragali Radix.

Chemical Authentication of Botanical Ingredients: A Review of Commercial Herbal Products

Chemical methods are the most important and widely used traditional plant identification techniques recommended by national and international pharmacopoeias. We have reviewed the successful use of different chemical methods for the botanical authentication of 2,386 commercial herbal products, sold in 37 countries spread over six continents. The majority of the analyzed products were reported to be authentic (73%) but more than a quarter proved to be adulterated (27%). At a national level, the number of products and the adulteration proportions varied very widely. Yet, the adulteration reported for the four countries, from which more than 100 commercial products were purchased and their botanical ingredients chemically authenticated, was 37% (United Kingdom), 31% (Italy), 27% (United States), and 21% (China). Simple or hyphenated chemical analytical techniques have identified the total absence of labeled botanical ingredients, substitution with closely related or unrelated species, the use of biological filler material, and the hidden presence of regulated, forbidden or allergenic species. Additionally, affecting the safety and efficacy of the commercial herbal products, other low quality aspects were reported: considerable variability of the labeled metabolic profile and/or phytochemical content, significant product-to-product variation of botanical ingredients or even between batches by the same manufacturer, and misleading quality and quantity label claims. Choosing an appropriate chemical technique can be the only possibility for assessing the botanical authenticity of samples which have lost their diagnostic microscopic characteristics or were processed so that DNA cannot be adequately recovered.

Integrated metabolomics and transcriptomics study of traditional herb Astragalus membranaceus Bge. var. mongolicus (Bge.) Hsiao reveals global metabolic profile and novel phytochemical ingredients

BACKGROUND

Astragalus membranaceus Bge. var. mongolicus (Bge.) Hsiao is one of the most common herbs widely used in South and East Asia, to enhance people's health and reinforce vital energy. Despite its prevalence, however, the knowledge about phytochemical compositions and metabolite biosynthesis in Astragalus membranaceus Bge. var. mongolicus (Bge.) Hsiao is very limited.

RESULTS

An integrated metabolomics and transcriptomics analysis using state-of-the-art UPLC-Q-Orbitrap mass spectrometer and advanced bioinformatics pipeline were conducted to study global metabolic profiles and phytochemical ingredients/biosynthesis in Astragalus membranaceus Bge. var. mongolicus (Bge.) Hsiao. A total of 5435 metabolites were detected, from which 2190 were annotated, representing an order of magnitude increase over previously known. Metabolic profiling of Astragalus membranaceus Bge. var. mongolicus (Bge.) Hsiao tissues found contents and synthetic enzymes for phytochemicals were significantly higher in leaf and stem in general, whereas the contents of the main bioactive ingredients were significantly enriched in root, underlying the value of root in herbal remedies. Using integrated metabolomics and transcriptomics data, we illustrated the complete pathways of phenylpropanoid biosynthesis, flavonoid biosynthesis, and isoflavonoid biosynthesis, in which some were first reported in the herb. More importantly, we discovered novel flavonoid derivatives using informatics method for neutral loss scan, in addition to inferring their likely synthesis pathways in Astragalus membranaceus Bge. var. mongolicus (Bge.) Hsiao.

CONCLUSIONS

The current study represents the most comprehensive metabolomics and transcriptomics analysis on traditional herb Astragalus membranaceus Bge. var. mongolicus (Bge.) Hsiao. We demonstrated our integrated metabolomics and transcriptomics approach offers great potentials in discovering novel metabolite structure and associated synthesis pathways. This study provides novel insights into the phytochemical ingredients, metabolite biosynthesis, and complex metabolic network in herbs, highlighting the rich natural resource and nutritional value of traditional herbal plants.

UV-B Radiation Largely Promoted the Transformation of Primary Metabolites to Phenols in Astragalus mongholicus Seedlings

: Ultraviolet-B (UV-B) radiation (280-320 nm) may induce photobiological stress in plants, activate the plant defense system, and induce changes of metabolites. In our previous work, we found that between the two Astragalus varieties prescribed by the Chinese Pharmacopoeia, Astragalus mongholicus has better tolerance to UV-B. Thus, it is necessary to study the metabolic strategy of Astragalus under UV-B radiation further. In the present study, we used untargeted gas chromatography-mass spectrometry (GC-MS) and targeted liquid chromatography-mass spectrometry (LC-MS techniques) to investigate the profiles of primary and secondary metabolic. The profiles revealed the metabolic response of Astragalus to UV-B radiation. We then used real-time polymerase chain reaction (RT-PCR) to obtain the transcription level of relevant genes under UV-B radiation (UV-B supplemented in the field, λmax = 313 nm, 30 W, lamp-leaf distance = 60 cm, 40 min·day-1), which annotated the responsive mechanism of phenolic metabolism in roots. Our results indicated that supplemental UV-B radiation induced a stronger shift from carbon assimilation to carbon accumulation. The flux through the phenylpropanoids pathway increased due to the mobilization of carbon reserves. The response of metabolism was observed to be significantly tissue-specific upon the UV-B radiation treatment. Among phenolic compounds, C6C1 carbon compounds (phenolic acids in leaves) and C6C3C6 carbon compounds (flavones in leaves and isoflavones in roots) increased at the expense of C6C3 carbon compounds. Verification experiments show that the response of phenolics in roots to UV-B is activated by upregulation of relevant genes rather than phenylalanine. Overall, this study reveals the tissues-specific alteration and mechanism of primary and secondary metabolic strategy in response to UV-B radiation.

Quality assessment of Astragali Radix from different production areas by simultaneous determination of thirteen major compounds using tandem UV/charged aerosol detector

To identify more chemical markers for improving the quality standard and evaluate producing areas differentiation of Astragali Radix (AR), a simple, low-cost and reliable chromatography method based on a high performance liquid chromatography (HPLC) coupled with ultraviolet (UV) detector and charged aerosol detector (CAD) for separation of 13 major chemical components, including 8 flavonoids and 5 astragalosides in AR extract, was developed. The contents of 13 compounds in total of 27 herb samples, collected from different cultivating regions, were determined and compared. Moreover, chemometric analysis techniques with principal component constituent analysis (PCA) and cluster analysis (CA) were performed to discriminate the samples from different producing areas. As a result, an obvious linkage between the content of components and collecting areas was found. Results showed that the content of astragaloside III and astragaloside IV could be used to differentiate samples collected from Northeast China, Inner Mongolia and Shanxi Province, suggesting that they should be added as the chemical marker for further investigation on the pharmacological actions and the quality control of AR.

Nuclear magnetic resonance based metabolomic differentiation of different Astragali Radix

Astragali Radix (AR) is one of the most popular herbal medicines in traditional Chinese medicine (TCM). Wild AR is believed to be of high quality, and substitution with cultivated AR is frequently encountered in the market. In the present study, two types of ARs (wild and cultivated) from Astragalus membranaceus (Fisch.) Bge. and A. membranaceus var. mongholicus (Bge.) Hsiao, growing in different regions of China, were analyzed by NMR profiling coupled with multivariate analysis. Results showed that both could be differentiated successfully and cultivation patterns or growing years might have greater impact on the metabolite compositions than the variety; the metabolites responsible for the separation were identified. In addition, three extraction methods were compared and the method (M1) was used for further analysis. In M1, the extraction solvent composed of water, methanol, and chloroform in the ratio of 1 : 1 : 2 was used to obtain the aqueous methanol (upper layer) and chloroform (lower layer) fractions, respectively, showing the best separation. The differential metabolites among different methods were also revealed. Moreover, the sucrose/glucose ratio could be used as a simple index to differentiate wild and cultivated AR. Meanwhile, the changes of correlation pattern among the differential metabolites of the two varieties were found. The work demonstrated that NMR-based non-targeted profiling approach, combined with multivariate statistical analysis, can be used as a powerful tool for differentiating AR of different cultivation types or growing years.

The Different Resistance of Two Astragalus Plants to UV-B Stress is Tightly Associated with the Organ-specific Isoflavone Metabolism

In this work, the changes in isoflavone levels and the expression of genes involved in their biosynthesis were studied in two Astragalus by UPLC-MS and real-time PCR after 10 days of UV-B treatment (λ_max  = 313 nm, 804 J m^-2 ). Isoflavones were significantly induced by UV-B irradiation. The influence might be activated by the regulation of these target genes. Our results indicate that (1) the resistance of Astragalus membranaceus might not be as good as Astragalus mongholicus in the enhanced UV-B radiation environment; (2) the enhanced accumulation of calycosin and calycosin-7-glucoside with UV-B treatment in roots of A. mongholicus might be derived from formononetin which is synthesized in the leaves; (3) the glycosylation process could be stimulated and activated by the enhanced UV-B radiation in both A. mongholicus and A. membranaceus. In other words, glycosylation of isoflavones might play a crucial role for two Astragalus plants in response to UV-B stress. Overall, this study offered a feasible elicitation strategy to understand the accumulation pattern of isoflavone in A. mongholicus and A. membranaceus, and also provided a reference for the changes in isoflavone levels of Astragalus in UV-B enhanced environment in the future.

Quantification of isoflavonoids and triterpene saponins in Astragali Radix, the root of Astragalus membranaceus, via reverse-phase high-performance liquid chromatography coupled with integrated pulsed amperometric detection

Astragali Radix, the root of Astragalus membranaceus Bunge, is one of the most frequently used crude drugs in Asian medicine. We developed a quantification method for 6 components (calycosin, formononetin, astragaloside I-IV) of Astragali Radix and Hwanggi-gyeji-omul-tang (HGOT) using reverse-phase high-performance liquid chromatography coupled with integrated pulsed amperometric detection (RP-HPLC-IPAD). The plants were extracted in 80% ethanol for 2h. All target components were detected with good sensitivity using sodium hydroxide (as a post-column eluent). The limit of detection (S/N=3) and limit of quantification (S/N=10) of the target components ranged from 0.10-1.00ng and from 0.30-3.00ng, respectively. The coefficients of linear regression ranged from 0.9993-1.0000, all interday and intraday precision values were <3.64%, and the average recovery ranged from 99.00-102.97% for Astragali Radix and 97.73-102.57% for HGOT. This method exhibited good selectivity, sensitivity, and reproducibility and can be used directly without any pretreatment steps. Our method will therefore be useful as a quality control measure for Astragali Radix.

System Pharmacology-Based Dissection of the Synergistic Mechanism of Huangqi and Huanglian for Diabetes Mellitus

The rapidly increasing diabetes mellitus (DM) is becoming a major global public health issue. Traditional Chinese medicine (TCM) has a long history of the treatment of DM with good efficacy. Huangqi and Huanglian are one of the most frequently prescribed herbs for DM, and the combination of them occurs frequently in antidiabetic formulae. However, the synergistic mechanism of Huangqi (Radix Astragali) and Huanglian (Rhizoma Coptidis) has not been clearly elucidated. To address this problem, a feasible system pharmacology model based on chemical, pharmacokinetic and pharmacological data was developed via network construction approach to clarify the synergistic mechanisms of these two herbs. Forty-three active ingredients of Huangqi (mainly astragalosides and isoflavonoids) and Huanglian (primarily isoquinoline alkaloids) possessing favorable pharmacokinetic profiles and biological activities were selected, interacting with 50 DM-related targets to provide potential synergistic therapeutic actions. Systematic analysis of the constructed networks revealed that these targets such as GLUT2, NOS2, PTP1B, and IGF1R were mainly involved in PI3K-Akt signaling pathway, insulin resistance, insulin signaling pathway, and HIF-1 signaling pathway, and were mainly located in retina, pancreatic islet, smooth muscle, immunity-related organ tissues, and whole blood. The contribution index of every active ingredient also indicated five compounds, including berberine (BBR), astragaloside IV (AIV), quercetin, palmatine, and astragalus polysaccharides, as the principal components of this herb combination. These results successfully explained the polypharmcological and synergistic mechanisms underlying the efficiency of Huangqi and Huanglian for the treatment of DM and its complications.

Metabolic profiling of the traditional Chinese medicine formulation Yu Ping Feng San for the identification of constituents relevant for effects on expression of TNF-α, IFN-γ, IL-1β and IL-4 in U937 cells

Yu Ping Feng San (YPFS) is a classical TCM formulation which has been traditionally used for treatment of immune system related diseases such as chronic bronchitis, allergic rhinitis and asthma. The formula is a mixture of Radix Saposhnikoviae (Fangfeng), Radix Astragali (Huangqi), and Rhizoma Atractylodis macrocephalae (Baizhu). TLC- and LC-DAD-ESI-MS/MS methods have been developed for the analysis of the metabolic profiles of the single herbs and of the formula. Decoctions and ASE extracts were analyzed in order to trace components of the individual herbs in YPFS. Nine constituents of Radix Saposhnikoviae, ten constituents of Radix Astragali and five constituents of Rhizoma Atractylodis macrocephalae have been assigned in the chemical profiles of the formula, which now allow the standardisation of YPFS. The pharmacological testing showed that all extracts significantly inhibited expression of TNF-α, IFN-γ, and IL-1β in U937 cells, while the inhibition of IL-4 was consistently low. Compared to conventional analyses which are focused on a limited set of compounds, metabolomics approaches, together with novel data processing tools, enable a more holistic comparison of the herbal extracts. In order to identify the constituents which are relevant for the immunomodulatory effects of the formula, metabolomics studies (PCA, OPLS-DA) have been performed using UPLC/QTOF MS data.

Calycosin and Formononetin Induce Endothelium-Dependent Vasodilation by the Activation of Large-Conductance Ca2+-Activated K+ Channels (BKCa)

Calycosin and formononetin are two structurally similar isoflavonoids that have been shown to induce vasodilation in aorta and conduit arteries, but study of their actions on endothelial functions is lacking. Here, we demonstrated that both isoflavonoids relaxed rat mesenteric resistance arteries in a concentration-dependent manner, which was reduced by endothelial disruption and nitric oxide synthase (NOS) inhibition, indicating the involvement of both endothelium and vascular smooth muscle. In addition, the endothelium-dependent vasodilation, but not the endothelium-independent vasodilation, was blocked by BK_Ca inhibitor iberiotoxin (IbTX). Using human umbilical vein endothelial cells (HUVECs) as a model, we showed calycosin and formononetin induced dose-dependent outwardly rectifying K⁺ currents using whole cell patch clamp. These currents were blocked by tetraethylammonium chloride (TEACl), charybdotoxin (ChTX), or IbTX, but not apamin. We further demonstrated that both isoflavonoids significantly increased nitric oxide (NO) production and upregulated the activities and expressions of endothelial NOS (eNOS) and neuronal NOS (nNOS). These results suggested that calycosin and formononetin act as endothelial BK_Ca activators for mediating endothelium-dependent vasodilation through enhancing endothelium hyperpolarization and NO production. Since activation of BK_Ca plays a role in improving behavioral and cognitive disorders, we suggested that these two isoflavonoids could provide beneficial effects to cognitive disorders through vascular regulation.

Simultaneous determination of six active metabolites in Astragalus mongholicus (Fisch.) Bge. under salt stress by ultra-pressure liquid chromatography with tandem mass spectrometry

Astragalus membranaceus Bge. var. mongholicus (Bge.) Hsiao (A. mongholicus, family Leguminosae) is one of the most important traditional Chinese herbs because it contains lots of bioactive metabolites, which have beneficial and pharmacological effects on health. Simultaneously, it has been proved to be a salt-tolerant plant-one of the potential species to control the soil salinization. Therefore, a sensitive and specific ultra-pressure liquid chromatography coupled with tandem mass spectrometric (UPLC-MS/MS) method was developed and validated for the simultaneous determination of six main bioactive metabolites, astragaloside IV, cycloastragenol, calycosin-7-O-β-d-glucoside, calycosin, ononin and formononetin in different organs of A. mongholicus. The detection was accomplished by multiple-reaction monitoring (MRM) scanning via electrospray ionization source operating in the positive ionization mode. Calibration curves offered linear ranges of two orders of magnitude with R(2) > 0.99. The method was fully validated for the linearity, intra-day and inter day precisions, accuracy, recovery, matrix effect and stability. Then this method was successfully applied to detect the content of major bioactive metabolites in different plant organs of A. mongholicus under salt stress. Significant variations in the content of six bioactive metabolites were observed after been processed by different levels of salinity in different part of plant. The results support for further exploration of the salt-tolerant mechanisms in A. mongholicus and its possibility as the species that control the soil salinization. Meanwhile, we established a UPLC-MS/MS assay of the trace components in seedling of A. mongholicus in this study.

Global transcriptome analysis profiles metabolic pathways in traditional herb Astragalus membranaceus Bge. var. mongolicus (Bge.) Hsiao

BACKGROUND

Astragalus membranaceus Bge. var. mongolicus (Bge.) Hsiao (A. mongolicus, family Leguminosae) is one of the most important traditional Chinese herbs. Among many secondary metabolites it produces, the effective bioactive constituents include isoflavonoids and triterpene saponins. The genomic resources regarding the biosynthesis of these metabolites in A. mongolicus are limited. Although roots are the primary material harvested for medical use, the biosynthesis of the bioactive compounds and its regulation in A. mongolicus are not well understood. Therefore, a global transcriptome analysis on A. mongolicus tissues was performed to identify the genes essential for the metabolism and to profile their expression patterns in greater details.

RESULTS

RNA-sequencing was performed for three different A. mongolicus tissues: leaf, stem, and root, using the Illumina Hiseq2000 platform. A total of 159.5 million raw sequence reads were generated, and assembled into 186,324 unigenes with an N50 of 1,524bp. Among them, 129,966 unigenes (~69.7%) were annotated using four public databases (Swiss-Prot, TrEMBL, CDD, Pfam), and 90,202, 63,946, and 78,326 unigenes were found to express in leaves, roots, and stems, respectively. A total of 8,025 transcription factors (TFs) were identified, in which the four largest families, bHLH, MYB, C3H, and WRKY, were implicated in regulation of tissue development, metabolisms, stress response, etc. Unigenes associated with secondary metabolism, especially those with isolavonoids and triterpene saponins biosynthesis were characterized and profiled. Most genes involved in the isoflavonoids biosynthesis had the lowest expression in the leaves, and the highest in the stems. For triterpene saponin biosynthesis, we found the genes in MVA and non-MVA pathways were differentially expressed among three examined tissues, indicating the parallel but compartmentally separated biosynthesis pathways of IPP and DMAPP in A. mongolicus. The first committed enzyme in triterpene saponin biosynthesis from A. mongolicus, cycloartenol synthase (AmCAS), which belongs to the oxidosqualene cyclase family, was cloned by us to study the astragalosides biosynthesis. Further co-expression analysis indicated the candidate CYP450s and glycosyltransferases (GTs) in the cascade of triterpene saponins biosynthesis. The presence of the large CYP450 families in A. mongolicus was further compared with those from Medicago truncatula and Arabidopsis thaliana, and the diversity and phylegenetic relationships of the CYP450 families were established.

CONCLUSION

A transcriptome study was performed for A. mongolicus tissues to construct and profile their metabolic pathways, especially for the important bioactive molecules. The results revealed a comprehensive profile for metabolic activities among tissues, pointing to the equal importance of leaf, stem, and root in A. mongolicus for the production of bioactive compounds. This work provides valuable resources for bioengineering and in vitro synthesis of the natural compounds for medical research and for potential drug development.

HPLC-DAD-ELSD Combined Pharmacodynamics and Serum Medicinal Chemistry for Quality Assessment of Huangqi Granule

Objective

To more scientifically and reasonably control the quality of Huangqi Granules, preliminary studies on the pharmacodynamics and serum pharmacochemistry of this medicine were performed. DPPH and MTT experiments showed that water extracts of Huangqi Granules had good antioxidant activity and increased immunity. Timed blood samples collected 5 min, 15 min, and 30 min after oral administration of a set amount of Huangqi Granules were collected and tested using UPLC-ESI-MS/MS. As a result, calycosin-7-O-β-D-glucoside, ononin, calycosin, astragaloside IV, and formononetin were found to exist in rat blood after dosing, indicating that the five chemical compounds might have pharmacological activity, and based on this result, they were designated biomarkers for quality control of Huangqi Granules. Consequently, a simple, rapid and efficient method was developed in the present study for the simultaneous determination of the five characteristic compounds in Huangqi Granules using HPLC-DAD-ELSD.

Materials and Methods

The separation was performed using an Agilent Hypersil ODS column (4.6 × 250 mm, 5 μm) at 30 ℃. The mobile phase was composed of water (solvent A) and acetonitrile (solvent B) with a flow rate of 1 mL/min. The drift tube temperature of the ELSD system was set to 85 ℃, and the nitrogen pressure was 3.5 bar.

Results

All five characteristic compounds had good linear behavior with r2 values greater than 0.9972. The recoveries varied from 96.31% to 101.22%. Subsequently, the developed method was applied to evaluate the quality of Huangqi Granules from different batches, and hierarchical clustering analysis (HCA) was used to analyze the classification of the samples based on the values of the five compounds.

Conclusion

The established HPLC method combined with HCA proved to be effective to evaluate the quality of Huangqi Granules.

Accumulation of flavonoids and related gene expressions in different organs of Astragalus membranaceus Bge

Astragalus membranaceus is one of the important medicinal plant in China and Korea. It is used to increase metabolism and digestion, enhance the immune system, and promote the healing of wounds and injuries. In the present study, we used quantitative real-time PCR to investigate the expression of genes related to the biosynthesis of flavonoids, in addition to high-performance liquid chromatography to assess calycosin and calycosin-7-O-β-D-glucoside accumulation, in the different plant organs of A. membranaceus. The transcript levels of all genes (AmPAL, AmC4H, Am4CL, AmCHS, AmCHR, AmCHI, AmIFS, AmI3'H, and AmUCGT) involved in calycosin and calycosin-7-O-β-D-glucoside biosynthesis were the highest in the flower. Calycosin content was ordered as follows: leaf (145.56 μg/g dry weight [DW]) > stem (18.3 μg/g DW) > root (1.64 μg/g DW) > flower (0.09 μg/g DW), whereas calycosin-7-O-β-D-glucoside content was ordered as follows: root (4.88 μg/g DW) > stem (3.86 μg/g DW) > leaf (2.0 μg/g DW) > flower (not detected). All genes exhibited the highest transcription levels in the flower, whereas calycosin and its glycoside content were the highest in the leaf and root, respectively. Our results indicate that the enhancement of calycosin-7-O-β-D-glucoside in the roots may originate from high calycosin accumulation in the stem and leaf. Thus, the mechanisms regulating calycosin and calycosin-7-O-β-D-glucoside content differ in the different organs of A. membranaceus. The results are expected to provide baseline information from which the mechanism of flavonoid biosynthesis in the different organs of A. membranaceus may be elucidated.

A network-based analysis of the types of coronary artery disease from traditional Chinese medicine perspective: potential for therapeutics and drug discovery

ETHNOPHARMACOLOGICAL RELEVANCE

Coronary heart disease (CAD) is one of the most dangerous threats to human health due to its high incidence and high mortality. CAD has several major types, such as blood stasis and qi deficiency according to the syndromes of diagnosis in traditional Chinese medicine (TCM), which are treated with different herbs or compound prescriptions. However, up to now a deep analysis of the relationship between CAD and its types both at molecular or systems levels is still unavailable, which greatly limits the combination of TCMs with Western drugs to form an integrative/alternative medicine for treatment of the complex disease.

MATERIALS AND METHODS

In this review, we attempt to decipher the underlying mechanisms of major types of CAD by connecting the drugs, targets and diseases to obtain the compound-target-disease associations for reconstructing the biologically-meaningful networks based on systems pharmacology method.

RESULTS

The results indicate that the herbs for eliminating blood stasis have pharmacological activity of dilating blood vessel, improving the microcirculation, reducing blood viscosity and regulating blood lipid, while qi-enhancing herbs have the potential for enhancing energy metabolism and anti-inflammation.

CONCLUSIONS

A systematic exploration of types of CAD may bring out the best between research on drug molecules and TCM phenotypic information, so as to accelerate development of network-based drug discovery as well as to facilitate the therapy of this disease.

Isoflavone production in Cyclopia subternata Vogel (honeybush) suspension cultures grown in shake flasks and stirred-tank bioreactor

Suspension cultures of the endemic South-African plant Cyclopia subternata were established for the first time and evaluated for the presence of isoflavones. The influence of light, as well as medium supplementation strategies with phenylalanine, casein hydrolysate and coconut water on biomass growth and isoflavone production were examined. The highest levels of 7-O-β-glucosides of calycosin, pseudobaptigenin and formononetin (275.57, 125.37 and 147.28 mg/100 g DW, respectively) were recorded for cultures grown in the absence of light, whereas coconut water substantially promoted biomass growth. Cell suspensions were subsequently grown in the 2-l stirred-tank bioreactor. Maximum productivity of 7-O-β-glucosides of calycosin, pseudobaptigenin and formononetin (0.96, 0.44 and 0.22 mg l⁻¹ day⁻¹, respectively) in bioreactor-cultivated cells was obtained for biomass grown in the dark and supplemented with coconut water. The results indicate that C. subternata suspension cultures can be utilised for the production of the specified isoflavone derivatives absent in the intact plant.

Chinese herbal medicine Huangqi type formulations for nephrotic syndrome

BACKGROUND

Patients with primary nephrotic syndrome mostly need immunosuppression to achieve remission, but many of them either relapse after immunosuppression therapy or resistant to it. On the other hand, immunosuppression therapy could increase the adverse effect. Huangqi and Huangqi type formulations have been used to treat nephrotic syndrome for years in China, however the effects and safety of these formulations have not been systematically reviewed. This is an update of a review first published in 2008.

OBJECTIVES

To assess the benefits and harms of Huangqi and Huangqi type formulations in treating nephrotic syndrome in any age group, either as sole agents or in addition to other drug therapies.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, Chinese Biomedicine Database (CBM), CNKI, VIP and reference lists of articles. There was no language restriction.Date of search: April 2011.

SELECTION CRITERIA

All randomised controlled trials (RCTs) assessing the use of Huangqi or Huangqi type formulations in treating nephrotic syndrome in adults and children, either as sole agents or in addition to other drug therapies.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed study quality and extracted data. For dichotomous outcomes results were expressed as relative risk (RR) and 95% confidence intervals (CI). Continuous outcomes were expressed as mean difference (MD) with 95% CI.

MAIN RESULTS

Nine studies were identified. One was judged to be at high risk of bias for random sequence, the rest were judged to be at low risk of bias. All studies had high risk of bias for allocation concealment and performance bias; unclear risk for detection bias and low risk for attrition bias. Two studies had unclear risk reporting bias and the rest had low risk. No other potential threats to validity were found. Compared to control interventions, Huangqi type formulations had a positive effect on plasma albumin (MD 6.41 g/dL, 95% Cl 4.24 to 8.59), urine albumin excretion (-0.57 g/24 h, 95% CI -1.04 to -0.10), cholesterol (MD -1.70 mmol/L, 95% Cl -2.60 to -1.13) and triglycerides (-0.33 mmol/L, 95% CI -0.63 to -0.03); and more patients showed improvement at three months (RR 0.41, 95% CI 0.20 to 0.84). There was no significant difference between Huangqi type formulations and control interventions for complete (RR 1.59, 95% CI 0.29 to 8.65) or partial remission (RR 1.22, 95% CI 0.57 to 2.58). While some formulations showed improvement in the number of patients achieving complete or partial remission, the number of studies (usually one per formulation), and the number patients (ranging from 38 to 78) were small. Relapse was reported at varying time points, ranging from three months to three years, and therefore these results were not pooled. Complications of nephrotic syndrome and adverse events were only reported by two studies; Only one study reported complications of nephrotic syndrome (infection) and another reported adverse reactions to treatment (Cushing's syndrome, steroid withdrawal syndrome, respiratory tract infection, and upper gastrointestinal haemorrhage). Both studies reported those treated with Huangqi type formulations had significantly less complications or adverse reactions.

AUTHORS' CONCLUSIONS

Huangqi and Huangqi type formulations may have some positive effects in treating nephrotic syndrome by increasing plasma albumin and reducing urine albumin excretion, blood cholesterol and triglycerides, and decreasing the number who don't show improvement at three months. Some formulations showed an increase in the number of patients achieving complete or partial remission, however study and participant numbers were small.

Quantification of six bioactive compounds in Zhenqi Fuzheng preparation by high-performance liquid chromatography coupled with diode array detector and evaporative light scattering detector

A simple and accurate high-performance liquid chromatography (HPLC) coupled with diode array detector (DAD) and evaporative light scattering detector (ELSD) was established for the determination of six bioactive compounds in Zhenqi Fuzheng preparation (ZFP). The monitoring wavelengths were 254, 275 and 328 nm. Under the optimum conditions, good separation was achieved, and the assay was fully validated in respect of precision, repeatability and accuracy. The proposed method was successfully applied to quantify the six ingredients in 31 batches of ZFP samples and evaluate the variation by hierarchical cluster analysis (HCA), which demonstrated significant variations on the content of these compounds in the samples from different manufacturers with different preparation procedures. The developed HPLC method can be used as a valid analytical method to evaluate the intrinsic quality of this preparation.

Study of the relationship between genetics and geography in determining the quality of Astragali Radix

Astragali Radix (AR), prepared from the roots of Astragalus membranaceus (FISCH. ex LINK) BUNGE or its variey, A. membranaceus (FISCH. ex LINK) BUNGE var. mongholicus (BUNGE) HSIAO., is one of the most used and valuable traditional Chinese medicines (TCMs). Historically, Hunyuan, Shanxi Province in China is the geo-authentic producing area of AR and crude AR from here called "geo-authentic." According to tradition, geo-authentic TCMs define both authenticity and quality. However, no scientific investigation has ever determined whether the superior quality of Hunyuan AR is due to the genetic characteristics or to the local environment. In our study, seeds of 30 AR samples representing the two varieties from different regions were cultivated in Hunyuan under the same conditions. A method, using ultra-performance liquid chromatography coupled with photodiode array detector and evaporative light scattering detectors, was developed to evaluate the quality through a simultaneous determination of four major isoflavonoids and four major saponins. The two AR varieties were successfully distinguished by principal component analysis while samples of the same species with different seeds origins could not be distinguished. A genetic study demonstrated that the internal transcribed spacer sequences of the nuclear ribosomal DNA in A. membranaceus var. mongholicus samples from different geographical regions were highly conservative. These results indicate that the content of active components in AR depends on the interaction of genotype and environment. At the varietal level, genetic properties appear to be more important for pharmaceutical quality than environmental factors, while on the intraspecific level environmental factors might be more important than genetic properties.

Comparative chemical analysis of Radix Astragali and Radix Hedysari by HPLC

Radix Astragali and Radix Hedysari, two famous traditional Chinese medicines (TCM), were considered to possess the same efficacy in TCM traditionally. However, modern pharmacological and phytochemical investigations showed that they were different in efficacy and chemical constituents to some degree. In this study, the principal constituents of the two drugs, isoflavonoids and saponins, were comparatively analysed using HPLC-UV and HPLC-ELSD methods. The results showed that there were some common compounds, especially flavonoids, in both drugs, while the differences in the types and contents of their chemical constituents, especially in saponins, were also obvious. The similarities and differences of the chemicals may be responsible, at least partially, for the similarities and differences in their efficacies or bioactivities.

Brazilian red propolis: unreported substances, antioxidant and antimicrobial activities

BACKGROUND

Chloroform, ethyl acetate and methanol extracts of a sample of red propolis from the state of Alagoas (northeast Brazil) were analyzed by gas chromatography-mass spectrometry and high-performance liquid chromatography-diode array detection-electrospray ionization-mass spectrometry. Antimicrobial and antioxidant activities were also obtained.

RESULTS

The propolis sample contained low content of narigenin-8-C-hexoside, this being the first report of a C-glycoside in propolis. The main constituent found was characterized as 3,4,2',3'-tetrahydroxychalcone. Other important constituents were the chalcone isoliquiritigenin, the isoflavans (3S)-vestitol, (3S)-7-O-methylvestitol, the pterocarpan medicarpin, the phenylpropenes trans-anethol, methyl eugenol, elimicin, methoxyeugenol and cis-asarone, and the triterpenic alcohols lupeol and α- and β- amyrins. The methanol extract exhibited high antioxidant activities by 2,2-diphenyl-1-picrylhydrazyl and β-carotene/linoleic acid assay methods, and antimicrobial activity toward Gram-positive and Gram-negative bacteria.

CONCLUSION

Structures are suggested for new substances never before seen in any kind of propolis. This is the first report of 3,4,2',3'-tetrahydroxychalcone and a flavone C-glycoside in a propolis sample.

Ultraviolet irradiation induces accumulation of isoflavonoids and transcription of genes of enzymes involved in the calycosin-7-O-β-d-glucoside pathway in Astragalus membranaceus Bge. var. mongholicus (Bge.) Hsiao

Isoflavonoids are a group of phenolic secondary metabolites found almost exclusively in leguminous plants. Formononetin, calycosin and calycosin-7-O-β-d-glucoside (CG) are isoflavonoid products in the CG pathway. Accumulation of the three isoflavonoids plus daidzein and expression of six genes of enzymes involved in the CG pathway were studied in Astragalus membranaceus Bge. var. mongholicus (Bge.) Hsiao with ultraviolet (UV) irradiation. Our results showed that (1) main isoflavonoids in roots, stems and leaves were CG, daidzein and calycosin, respectively; they accumulated significantly under the induction of UV irradiation during 8 days but their content declined later; (2) expression of six genes of enzymes involved in the CG pathway was inhibited slightly at early stage but the expression was increased greatly afterward; (3) chalcone synthase, chalcone reductase and chalcone isomerase were expressed to their individual maximum level within shorter hours than were cinnamate 4-hydroxylase, isoflavone synthase (IFS) and isoflavone 3'-hydroxylase and (4) more calycosin but less daidzein accumulated in leaves. IFS was highly expressed in leaves, which might lead to high accumulation of the common precursor of daidzein and 2,7-dihydroxy-4'-O-methoxy-isoflavanone, the latter of which would be converted to formononetin, calycosin and CG via a series of reactions. Little daidzein accumulated in leaves, which suggested that rather than be converted to daidzein, the 2,7,4'-trihydroxyisoflavanone was probably more easily caught by 2-hydroxyisoflavanone 4'-O-methyltransferase and hence provided more precursors for formononetin. The findings were discussed in terms of the influence of UV irradiation in the accumulation of isoflavonoids.

Detection and identification of diterpenoid alkaloids, isoflavonoids and saponins in Qifu decoction and rat plasma by liquid chromatography-time-of-flight mass spectrometry

A liquid chromatography-time-of-flight mass spectrometric (LC-TOFMS) method has been developed for analysis of components in Qifu decoction (QFD), a traditional Chinese medical formula consisting of Radix Astragali and Acontium carmichaeli, and in rat plasma after oral administration. Based on accurate mass measurements within 3 ppm error for each molecular ion and subsequent fragment ions of TOFMS, as well as matching of empirical molecular formulae with those of published components in the in-house chemical library, a total of 44 major components including 21 diterpenoid alkaloids, 12 flavonoids and 11 saponins were identified in QFD. After oral administration of QFD, 22 components in rat plasma were detected and identified by comparing and contrasting the constituents measured in QFD with those in the plasma samples. The results provided valuable chemical information for further pharmacology and active mechanism research on QFD. LC-TOFMS was also applied for the comparison of relative peak area of major active components between QFD and the single herb extracts. The concentration ratios of major saponins detected in the crude herb Radix Astragali were found to be different from those in QFD. The experimental data indicated that the decocting process could result in differences in the amounts of active components.

Comparison of the immunoregulatory function of different constituents in radix astragali and radix hedysari

Radix Astragali (RA), known as “Huangqi” in China, is one of the most popular herbal medicines known worldwide to reinforce “Qi”. RA is traditionally prepared from the dried roots of Astragalus membranaceus (MJHQ) and A. membranaceus var. mongholicus (MGHQ). Radix Hedysari is named “Hongqi” (HQ), which is similar to RA. We assessed and compared the chemical constituents and bioactivity of RA and HQ. Different constituents were extracted into five major parts and were analyzed using different methods. Comparison of the immunological effects of extracts was done by using two immunological models. Results showed that flavonoids and saponins present in RA and HQ were not only structurally significantly different but also different in their immunological effect. Amino acids extract (AE) in MGHQ shows immunological effect while AE in MJHQ and HQ did not. Polysaccharides comprised the major constituents in RA and HQ. All polysaccharides extract (PE) of the three herbs showed similar levels of immunological effect in both immunological assays.

Determination of nine active components in Radix Hedysari and Radix Astragali using capillary HPLC with diode array detection and MS detection

A capillary HPLC (cHPLC) coupled with diode array detection (DAD) and MS method was developed for the simultaneously qualitative and quantitative determination of nine components, namely vanillic acid, calycosin-7-O-beta-D-glucoside, (6alphaR,11alphaR)-9,10-dimethoxypterocarpan-3-O-beta-D-glucoside, ononin, calycosin, (3R)-2'-hydroxy-3',4'-dimethoxyisoflavan-7-O-beta-D-glucoside, isoliquiritigenin, formononetin, (3R)-8,2'-dihydroxy-7,4'-dimethoxyisoflavan, in Radix Hedysari (Hongqi) and Radix Astragali (Huangqi). Simultaneous separation of these nine compounds was achieved on a Zorbax C18 microcolumn (5 microm, 150 x 0.3 mm). The mobile phase consisted of (A) 0.3% aqueous formic acid and (B) ACN with a gradient elution. The identification of nine compounds in both Hongqi and Huangqi was confirmed by TOF-MS. All calibration curves showed good linearity (R(2) >0.998) within test ranges. This method showed good repeatability for the quantification of these nine components in Hongqi and Huangqi with intra- and inter-day variations of less than 1.89 and 3.13%, respectively. The validated method was successfully applied to quantify nine investigated components in eighteen samples of Hongqi and Huangqi. Hierarchical cluster analysis of 18 samples was performed using the peak area of nine analytes on cHPLC chromatograms. The result showed that Hongqi and Huangqi are significantly different, though the two species of Astragalus are very similar.

Chinese herbal medicine Huangqi type formulations for nephrotic syndrome

BACKGROUND

At present, there is a lack of safe and effective drugs for nephrotic syndrome (NS). Huangqi type formulations have been used to treat nephrotic syndrome for years in China, however the effects and safety of these formulations have not been systematically reviewed.

OBJECTIVES

To assess the benefits and harms of Huangqi and Huangqi type formulations in treating NS in any age group, either as sole agents or in addition to other drug therapies.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, Chinese Biomedicine Database (CBM), CNKI, VIP and reference lists of articles. There was no language restriction. Date of most recent search: June 2006.

SELECTION CRITERIA

All randomised controlled trials (RCTs) assessing the use of Huangqi or Huangqi type formulations in treating NS in adults and children, either as sole agents or in addition to other drug therapies.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed study quality and extracted data. For dichotomous outcomes (remission, side effects and Inefficacy rate), results were expressed as relative risk (RR) and 95% confidence intervals (CI). Continuous outcomes (triglycerides cholesterol, plasma albumin) results were expressed as mean difference (WMD) with 95% CI.

MAIN RESULTS

Three studies were identified (n = 128), all comparing Huangqi type formulations with placebo. Huangqi injection had a positive effect on plasma albumin (WMD 6.90, 95% Cl 3.60 to 10.20) and cholesterol (WMD 2.13, 95% Cl -2.97 to -1.29). Huangqi and red Chinese date reduced some adverse reactions (Cushing's syndrome: RR 0.55, 95% Cl 0.32 to 0.94; hormone reduced syndrome: RR 0.58, 95% Cl 0.39 to 0.85, respiratory tract infection: RR 0.27, 95% Cl 0.08 to 0.88), but no benefit on reducing relapse. Huangqi and Danggui had a positive effect on cholesterol (WMD -0.85, 95% Cl -1.70 to 0.00).

AUTHORS' CONCLUSIONS

Huangqi type formulations may have some positive effects in treating NS by increasing plasma albumin and reducing blood cholesterol, Cushing's syndrome, hormone reduced syndrome and respiratory tract infection. However, limited by the lack of high quality clinical studies, we are unable to recommend Huangqi type formulations for NS. Large, properly randomised, placebo-controlled, double-blind studies are required.

Simultaneous determination of 15 marker constituents in various radix Astragali preparations by solid-phase extraction and high-performance liquid chromatography

An improved quality control method was developed to simultaneously determine 15 major constituents (eight flavonoids and seven saponins) in various radix Astragali preparations, using SPE for pretreatment of samples, HPLC with diode-array and evaporative light scattering detectors (DAD-ELSD) for quantification in one run, and HPLC-ESI-TOF/MS for definite identification of compounds in preparations. Optimum separations were obtained with a ZORBAX C(18) column, using a gradient elution with 0.3% aqueous formic acid and ACN. This established method was fully validated with respect to linearity, precision, repeatability, and accuracy, and was successfully applied to quantify the 15 compounds in 19 commercial samples, including 3 dosage forms, i. e., oral solution, injection, concentrated granule, and its processed products of radix Astragali. The results demonstrated that many factors might result in significant differences in quality of the final preparations, including crude drugs, pretreatment processes, manufacturing procedure, storage conditions, etc. Then the developed method provided a reasonable and powerful manner to ensure the efficacy, safety, and batch-to-batch uniformity of radix Astragali products by standardizing each procedure, and thus should be proposed as quality control for the clinical use and modernization of herbal preparations.

Application of high-performance liquid chromatography-electrospray ionization time-of-flight mass spectrometry for analysis and quality control of Radix Astragali and its preparations

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.