Identification of major α-glucosidase inhibitors in Radix Astragali and its human microsomal metabolites using ultrafiltration HPLC–DAD–MSn

Neuropharmacological effects of calycosin: a translational review of molecular mechanisms and therapeutic applications

Calycosin, a naturally occurring isoflavonoid found predominantly in Astragalus membranaceus, exhibits significant therapeutic potential in various neurological conditions. Its multifaceted bioactive properties-antioxidant, anti-inflammatory, and anti-apoptotic-position it as a promising candidate for neuroprotection and neuroregeneration. This review explores calycosin's mechanisms of action, including its modulation of key signaling pathways such as HMGB1/TLR4/NF-κB (high mobility group box 1/toll-like receptor 4/nuclear factor kappa B), phosphatidylinositol-3-kinase (PI3 K)/Akt, ERK1/2 (extracellular signal-regulated kinase 1/2), and Hsp90/Akt/p38. In cerebral ischemia/reperfusion injury, calycosin reduces oxidative stress markers like ROS (reactive oxygen species) and MDA (malondialdehyde), enhances antioxidant enzymes (SOD (superoxide dismutase) and GPX (glutathione peroxidase)), and downregulates pro-inflammatory cytokines (TNF-α, IL-1β) through the HMGB1/TLR4/NF-κB pathway. It also inhibits autophagy via the STAT3/FOXO3a pathway and apoptosis by modulating Bax and Bcl-2 expression. In neuro-oncology, calycosin inhibits glioblastoma cell migration and invasion by modulating the TGF-β-mediated mesenchymal properties and suppressing the c-Met and CXCL10 signaling pathways. Additionally, it enhances the efficacy of temozolomide in glioma treatment through apoptotic pathways involving caspase-3 and caspase-9. Calycosin shows promise in Alzheimer's disease by reducing β-amyloid production and tau hyperphosphorylation via the GSK-3β pathway and improving mitochondrial function through the peroxisome proliferator-activated receptor gamma coactivator 1-Alpha (PGC-1α)/mitochondrial transcription factor A (TFAM) signaling pathway. In Parkinson's disease, calycosin mitigates oxidative stress, prevents dopaminergic neuronal death, and reduces neuroinflammation by inhibiting the TLR/NF-κB and MAPK pathways. It has also shown therapeutic potential in meningitis and even neuroprotective effects against hyperbilirubinemia-induced nerve injury. Despite these promising findings, further research, including detailed mechanistic studies and clinical trials, is needed to fully understand calycosin's therapeutic mechanisms and validate its potential in human subjects. Developing advanced delivery systems and exploring synergistic therapeutic strategies could further enhance its clinical application and effectiveness.

Affinity Ultrafiltration Mass Spectrometry for Screening Active Ingredients in Traditional Chinese Medicine: A Review of the Past Decade (2014-2024)

Discovering targets in natural products is a critical and challenging task in new drug development. Rapid and efficient screening of active ingredients from complex systems like traditional Chinese medicine (TCM) is now crucial in drug research. Affinity ultrafiltration (AUF) technology is widely used to screen active ingredients in natural medicines. AUF-liquid chromatography-mass spectrometry (AUF-LC-MS) leverages the affinity between natural medicine extracts and targets to isolate active ingredients from complex matrices, employing LC-MS for detection and activity assessment. This review discusses the developments in employing AUF-LC-MS to analyze TCM and TCM compound preparations over the last decade. This review succinctly presents the advantages and limitations of AUF-LC-MS, illustrating its benefits through the example of screening for active ingredients in natural pharmaceuticals.

Astragali radix (Huangqi): a time-honored nourishing herbal medicine

Astragali radix (AR, namded Huangqi in Chinese) is the dried root of Astragalus membranaceus (Fisch.) Bge. var. mongholicus (Bge.) Hsiao or Astragalus membranaceus (Fisch.) Bge. As a widely used ethnomedicine, the biological activities of AR include immunomodulatory, anti-hyperglycemic, anti-oxidant, anti-aging, anti-inflammatory, anti-viral, anti-tumor, cardioprotective, and anti-diabetic effects, with minimum side effects. Currently, it is known that polysaccharides, saponins, and flavonoids are the indispensable components of AR. In this review, we will elaborate the research advancements of AR on ethnobotany, ethnopharmacological practices, phytochemicals, pharmacological activities, clinical uses, quality control, production developments, and toxicology. The information is expected to assist clinicians and scientists in developing useful therapeutic medicines with minimal systemic side effects.

Screening and identification of neuraminidase inhibitors from Baphicacanthus cusia by a combination of affinity ultrafiltration, HPLC-MS/MS, molecular docking, and fluorescent techniques

Natural products provide a new opportunity for the discovery of neuraminidase (NA)inhibitors. In this study, an affinity ultrafiltration (AUF) coupled with HPLC-MS/MS method was firstly developed and optimized for screening of NA inhibitors from natural products. The critical factors influencing the interaction of enzyme-ligand (including sample concentration, enzyme concentration, incubation time and temperature, pH of the buffer, and dissociation solvents and time) were investigated and optimized by a one-factor-at-a-time design. The method was then applied to discover NA inhibitory compounds in stems and leaves of Baphicacanthus cusia. As a result, five active alkaloids were screened out and identifiedas 2,4(1H,3H)-quinazolinedione (1), 4(3H)-quinazolinone (2), 2(3H)-benzoxazolone (3), tryptanthrin (4), and indirubin (5) through analysis of their DAD profiles, MS/MS fragments, and comparison with reference substances. These active compounds were further evaluated for their NA inhibitory activity using a fluorescence-based NA inhibition assay. The result from the fluorescent assay revealed that all the five compounds(1-5) showed pronounced NA inhibitory activities with IC50values of 98.98, 64.69, 40.16, 69.44, and 144.73 μM, respectively. Finally, molecular docking of these five alkaloids with NA showed that hydrogen bond and π-cation interactions dominated within the binding sites with binding energies ranging between -5.7 to -7.9 kcal/mol, which was supported by the results of the AUF and the fluorescence-based enzyme assay. The developed AUF method is simple and efficient for screening potential NA inhibitors from stems and leaves of B. cusia.

Recent updates in anti-glycation strategies: selection of natural products and lactic acid bacteria as potential inhibitors based on the multi-pathway anti-glycation targets

The prevalence of high-sugar diets and unhealthy habits exacerbates the production of advanced glycation end products (AGEs) in the body. When AGEs excessively accumulate in the body, they accelerate the aging process while directly or indirectly causing other complications that can seriously damage the body. Prevention of glycation damage is gaining increasing attention; however, a systematic strategy to combat glycation and specific glycation inhibitors is still lacking. By analyzing the process of glycation damage, we suggest that glycation damage can be mitigated by the inhibition of AGEs production, binding to proteins, and binding to receptors for advanced glycation end products, as well as the attenuation of downstream linkage reactions. This review summarizes the process of glycation damage. According to each step of the process, the review presents the corresponding anti-glycation strategies. Based on recent anti-glycation studies, we support the fabrication of glycation inhibitors by using natural plant products and fermentation products of lactic acid bacteria that partially exhibit anti-glycation properties. This review summarizes the mechanisms by which these dietary ingredients perform anti-glycation functions, providing relevant research evidence. We hope that this review will support and assist subsequent investigations in the development of anti-glycation inhibitors.

Design, synthesis, biological evaluation, and docking study of chromone-based phenylhydrazone and benzoylhydrazone derivatives as antidiabetic agents targeting α-glucosidase

To develop novel α-glucosidase inhibitors, a series of chromone-based phenylhydrazone and benzoylhydrazone derivatives were designed, synthesized, and evaluated their inhibitory effects on α-glucosidase. The target compounds were characterized using ¹H NMR, ¹³C NMR, and high-resolution mass spectra. Some of the compounds showed a varying degree of α-glucosidase inhibitory activity with IC₅₀ values ranging from 6.59 ± 0.09 to 158.55 ± 0.87 μM. Among them, compound 5c (IC₅₀ = 6.59 ± 0.09 μM) was the most potent inhibitor by comparison with positive control acarbose (IC₅₀ = 685.11 ± 7.46 μM). Enzyme kinetic, fluorescence analysis, circular dichroism spectra, and molecular docking techniques were employed to explain the underlying molecular mechanisms of 5c inhibition on α-glucosidase. In vivo sucrose-loading test showed that 5c could suppress the rise of blood glucose levels after loading sucrose in normal Kunming mice. The cytotoxicity assay indicated that 5c exhibited low cytotoxicity.

Chemical Characterization, α-Glucosidase, α-Amylase and Lipase Inhibitory Properties of the Australian Honey Bee Propolis

The use of functional foods and nutraceuticals as a complementary therapy for the prevention and management of type 2 diabetes and obesity has steadily increased over the past few decades. With the aim of exploring the therapeutic potentials of Australian propolis, this study reports the chemical and biological investigation of a propolis sample collected in the Queensland state of Australia which exhibited a potent activity in an in vitro α-glucosidase inhibitory screening. The chemical investigation of the propolis resulted in the identification of six known prenylated flavonoids including propolins C, D, F, G, H, and solophenol D. These compounds potently inhibited the α-glucosidase and two other enzymes associated with diabetes and obesity, α-amylase, and lipase on in vitro and in silico assays. These findings suggest that this propolis is a potential source for the development of a functional food to prevent type 2 diabetes and obesity. The chemical analysis revealed that this propolis possessed a chemical fingerprint relatively similar to the Pacific propolis found in Okinawa (South of Japan), Taiwan, and the Solomon Islands. This is the first time the Pacific propolis has been identified in Australia.

Pharmaceutical Values of Calycosin: One Type of Flavonoid Isolated from Astragalus

Astragalus is a popular Materia Medica in China, and it could be applied in the treatment of various diseases. It contains a variety of chemically active ingredients, such as saponins, flavonoids, and polysaccharides. Plant-derived bioactive chemicals are considered natural, safe, and beneficial. Among the infinite plant-identified and isolated molecules, flavonoids have been reported to have positive effects on human health. Calycosin is the most important active flavonoid substance identified predominantly within this medicinal plant. In recent years, calycosin has been reported to have anticancer, antioxidative, immune-modulatory, and estrogenic-like properties. This review collected recent relevant literatures on calycosin and summarized its potential pharmaceutical properties and working mechanism involved, which provided solid basis for future clinical research.

Rapid and comprehensive profiling of α-glucosidase inhibitors in Buddleja Flos by ultrafiltration HPLC-QTOF-MS/MS with diagnostic ions filtering strategy

Buddleja Flos is used as yellow rice colorant and a well-known traditional Chinese medicine. But its biochemical profiling is still lack due to complex matrix. Here, ultrafiltration high-performance liquid chromatograph-quadrupole time-of-flight tandem mass spectrometry (HPLC-QTOF-MS/MS) with diagnostic ions filtering strategy was proposed for rapid and comprehensive investigation of its α-glucosidase inhibitors. As a result, 33 bioactive compounds (13 phenylethanoid glycosides and 20 flavonoids) were successfully screened and identified. In addition, α-glucosidase inhibitory activities of twenty-two references were verified. Six flavonoid aglycones (4, 28, and 30-33) showed excellent α-glucosidase inhibitory activities (IC₅₀, from 5.11 ± 0.85 to 32.49 ± 9.76 μg/mL), much higher than that of acarbose (IC₅₀, 195.49 ± 10.05 μg/mL). Five flavonoid-monoglycosides (7, 12, 13, 20, and 22) presented moderate inhibitory activities with IC₅₀ from 160.98 ± 23.19 to 249.37 ± 35.83 μg/mL. Results showcased the high efficiency of proposed strategy in profiling of bioactive compounds from natural products.

Construction of Fe3O4@α-glucosidase magnetic nanoparticles for ligand fishing of α-glucosidase inhibitors from a natural tonic Epimedii Folium

Inhibition of α-glucosidase activity is an effective way for treatment of type 2 diabetes mellitus. Epimedii Folium is an important source of α-glucosidase inhibitors (AGIs), however bioactive compounds and pharmacological mechanisms remained unclear. In this study, a novel strategy was established, which harnessed α-glucosidase functionalized magnetic beads to fish out potential AGIs, followed by UPLC-MS/MS analysis for their identification. Furthermore, molecular docking was employed to predict binding patterns between the AGIs and the enzyme, and IC₅₀ values was estimated as well. After response surface methodology optimization, the highest activity of Fe₃O₄@α-glucosidase has been achieved when 1.17 mg/mL of α-glucosidase was immobilized in phosphate buffer (pH 6.81) for 4.22 h. Moreover, eight flavonoids were fished out from the extract of Epimedii Folium, and then identified to be epimedin A, epimedin B, epimedin C, icariin, sagittatoside A, sagittatoside B, 2"-O-rhamnosyl icariside II and baohuoside I. All of them were further confirmed to be AGIs through in vitro inhibitory assay and molecular docking. Among those, baohuoside I and sagittatoside B possessed stronger inhibitory activity than acarbose. The approach has a significant prospect in conveniently screening bioactive compounds that target various receptors, which provided an efficient platform for new drug development from natural products.

Fermentation of Danggui Buxue Tang, an ancient Chinese herbal mixture, together with Lactobacillus plantarum enhances the anti-diabetic functions of herbal product

Background

Danggui Buxue Tang (DBT), an ancient Chinese herbal decoction containing Astragali Radix and Angelicae Sinensis Radix at a ratio of 5: 1, is prescribed for menopausal women. Flavonoids and its flavonoid glycosides are considered as the major active ingredients within the herbal decoction; however, their amount is not controllable during the preparation. Besides, the aglycons within DBT are believed to have better gut absorption and pharmacological efficacy.

Methods

The herbal extract of DBT was fermented with Lactobacillus plantarum. The amounts of flavonoid glucosides and its aglycones in the fermented product were analyzed by using UPLC-MS/MS. In addition, in vitro assays were employed to evaluate the efficacy of the fermented DBT in regulating the activities of α-glucosidase, α-amylase and lipase, as well as their antioxidant capacity (DPPH and T-AOC assays) and anti-glycation property (BSA-methylglyoxal, BSA-fructose, and arginine-methylglyoxal models).

Results

The fermentation of DBT with L. plantarum drove a completed conversion of calycosin-7-O-β-D-glucoside and ononin to calycosin and formononetin, respectively. The chemical transformation could be probably mediated by β-glycosidase within the fermented product. Several in vitro assays corresponding to anti-diabetic functions were compared between parental DBT against its fermented product, which included the activities against α-glucosidase, α-amylase and lipase, as well as anti-oxidation and anti-glycation. The fermented DBT showed increased activities in inhibiting α-glycosidase, suppressing DPPH radical-scavenging and anti-glycation, as compared to the original herbal product.

Conclusion

These results suggested that DBT being fermented with the probiotic L. plantarum could pave a new direction for fermentation of herbal extract, as to strengthen its pharmacological properties in providing health benefits.

Simultaneous UPLC-TQ-MS/MS determination of six active components in rat plasma: application in the pharmacokinetic study of Cyclocarya paliurus leaves

Background

Cyclocarya paliurus (Batal.) Ijinskaja (CP) is a monotypic genus plant, also called sweet tea tree that belongs to the Juglandaceae family, which is mainly distributed in the subtropical highlands in China. Our previous work has verified that CP leaves exhibit a potent hyperglycemic effect by inhibiting pancreatic β cell apoptosis through the regulation of MPAK and Akt signaling pathways. However, the components that contribute to this potential health benefit remain undiscovered.

Method

A sensitive, reliable, and validated ultra-performance liquid chromatography coupled with triple-quadrupole tandem mass spectrometry (UPLC–TQ-MS/MS) method was developed to simultaneously determine the presence of six active components (neochlorogenic acid, chlorogenic acid, quercetin-3-O-glucuronide, kaempferol-3-O-rhamnoside, quercetin, and kaempferol) in rat plasma after a single oral administration (in a dosage of 10.5 g/kg) of an extract of CP leaves to rats. The separation was performed on a Waters ACQUITY BEH C₁₈ column (50 mm × 2.1 mm, 1.7 μm). The detection was conducted by multiple reaction monitoring (MRM) in negative ionization mode. The two highest abundant MRM transitions without interference were optimized for each analyte. Acetonitrile and formic acid aqueous solution (0.1%) was used as the mobile phase at a flow rate of 0.3 ml/min.

Result

The precision, accuracy, and recovery all satisfied the criteria of international guidance (Bioanalytical Method Validation Guidance for Industry, Food and Drug Administration), and the analytes were stable in plasma for all tested conditions. The main pharmacokinetic parameters were calculated by plasma concentration versus time profiles using the pharmacokinetics program.

Conclusion

The pharmacokinetic parameters of each compound can facilitate future clinical studies.

Aldose Reductase, Protein Glycation Inhibitory and Antioxidant of Peruvian Medicinal Plants: the Case of Tanacetum parthenium L. and Its Constituents

Diabetes complications, including peripheral neuropathy, cataracts, impaired wound healing, vascular damage, arterial wall stiffening and retinopathy diseases, are among the most predominant health problems facing the world's population today. The 22 Peruvian plant extracts were screened for their potential inhibitory activity against rat lens aldose reductase (RLAR) and DPPH radical scavenging. Among them, we have found that Tanacetum parthenium L. (TP) has the RLAR, AGEs and DPPH radical scavenging activities. We used for screening of active components in TP against RLAR and DPPH for the first time by ultrafiltration (UF) and DPPH. Compounds in TP were isolated by Sephadex column chromatography and their structures were established by MS and NMR spectroscopic analyses. Among the isolated compounds, ferulic acid, apigenin, luteolin-7-O-glucoside, luteolin, chrysosplenol, and kaempferol showed potent inhibition with IC50 values of 1.11-3.20 and 6.44-16.23 μM for RLAR and DPPH radical scavenging. Furthermore, these compounds suppressed sorbitol accumulation in rat lenses and ferulic acid, luteolin-7-O-glucoside, and luteolin have AGEs inhibitory activities with IC50 values of 3.43-6.73 μM. In summary, our study provides interesting plants for further study with respect to the treatment and prevention of diabetic complication of Peruvian plant and can provide the scientific base of the traditional uses.

Identification of α-glucosidase inhibitors from cyclocarya paliurus tea leaves using UF-UPLC-Q/TOF-MS/MS and molecular docking

11 potential α-glucosidase inhibitors in leaves of Cyclocarya paliurus were quickly identified by UF-UPLC-Q/TOF-MS/MS, and their inhibitory activities were verified in vitro and in vivo, as well as docked with homology model.

Enzyme immobilized on polyamidoamine-coated magnetic microspheres for α-glucosidase inhibitors screening from Radix Paeoniae Rubra extracts accompanied with molecular modeling

In this study, a method for direct screening and identification of α-glucosidase inhibitors (AGIs) from extracts of natural products was established based on polyamidoamine (PAMAM) coated magnetic microspheres. A facile route to synthesize the magnetic PAMAM was employed and α-glucosidase was successfully covalently attached to its surface through cross linking of glutaraldehyde. Using the enzyme-loaded magnetic microspheres, potential inhibitors were fished out from crude extracts directly, followed by structure confirmation. The inhibitory activities of the screened components were further investigated by the enzyme-loaded magnetic microspheres. The Fe₃O₄ @PAMAM@α-Glu microspheres displayed favorable dispersibility, fast magnetic separation, large enzyme binding amount (42.9 μg•mg^-1) and high enzyme activity. Moreover, the α-glucosidase on the surface of PAMAM coating maintained high storage stability and remarkable reusability. Taking advantage of specific interaction of the α-glucosidase with AGIs, the materials could selectively capture a known AGI (+)-catechin under the interference of an inactive compound salicylic acid, with a binding capacity as high as 15.4%. Additionally, using the Fe₃O₄ @PAMAM@α-Glu microspheres in the inhibition assay, the enzymatic reaction could be stopped by magnetic separation instead of the traditional addition of Na₂CO₃ solution, which not only eliminated the disturbance of termination reagent to the results, but also reused the immobilized α-glucosidase. The screening and inhibitory activity verification of potential ligands in Radix Paeoniae Rubra ("Chi-shao" in Chinese) extracts were achieved by using Fe₃O₄ @PAMAM@α-Glu microspheres, demonstrating practical applicability of our method. Therefore, the magnetic PAMAM-based screening approach could be a feasible and alternative strategy for discovering enzyme inhibitors from natural product extracts.

Metabolite profiling of traditional Chinese medicine formula Dan Zhi Tablet: An integrated strategy based on UPLC-QTOF/MS combined with multivariate statistical analysis

Metabolites derived from traditional Chinese medicine (TCM) are becoming active substances of pharmacologically as well as promising sources for discovering new drugs. However, detection and identification of constituents in vivo remains a challenge for TCM, due to massive endogenous interference and low abundance of metabolites in biological matrix. Traditional Chinese medicine formula Dan Zhi Tablet (DZT), a well-established TCM formula developed based on years of clinical experiences, was widely used to treat cerebral infraction disease. In this study, an integrated strategy based on ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-QTOF/MS) was adopted to comprehensively identify the prototype and metabolite constituents of DZT. The potential constituents were screened by cross orthogonal partial least-squares discriminant analysis (OPLS-DA). Automatic matching analysis was performed on UNIFI platform based on the function of predicting metabolites. Using this strategy, a total of 170 compounds, including 51 prototype constituents and 119 metabolites were unambiguously or tentatively identified in rat plasma. Furthermore, 31 compounds have also been detected in rat cerebrospinal fluid. The metabolism reactions included phase I reactions (hydroxylation, hydrolysis, deglycosylation, hydrogenation, demethylation and dehydroxylation) and phase II reactions (conjugation with glutatione, cysteine, acetylcysteine, glucuronide, sulfate). It is the first systematic metabolic study of DZT in vivo and some metabolites were also reported for the first time, which could provide a scientific basis for explaining the multiple functions of DZT. More importantly, the integrated strategy also shows promising perspectives in the identification of the metabolites in TCM from a complicated biological matrix.

Quality evaluation for Radix Astragali based on fingerprint, indicative components selection and QAMS

Radix Astragali (RA) is one of the most widely used Chinese herbs prescribed in many Chinese formulas to reinforce 'Qi' and treat vital energy deficiency. This study combined fingerprinting with quantitative analysis multi-components by a single marker (QAMS) to improve the quality control standard for RA on the basis of existing quality control methods of traditional Chinese medicinal materials. UPLC-ESI-TOF-MS technique was used to evaluate the quality of RA by fingerprinting and QAMS. Using the anti-inflammatory, anti-oxidation and anti-anoxic activities to screen characteristic components of RA, the calycosin-7-O-β-d-glucoside (CG), ononin, astragaloside IV, astragaloside II, calycosin and astrageloside I significantly inhibited ear edema in mice, the calycosin and CG had good antioxidant activity and the astragaloside I had a significant anti-hypoxia activity. Astragaloside I, astragaloside II, astragaloside IV, ononin, calycosin and CG had significant pharmacological actions. These components were comprehensively used as the indicative components for the quality control of RA. Astragaloside I was used as the internal standard of the relative correction factors of CG (13.45), ononin (0.51), calycosin (12.08), astragaloside IV (0.73) and astragaloside II (0.81). Astragaloside I and CG were used as internal standards of the relative correction factors of the flavonoids and saponins of ononin (1.11), calycosin (0.04), astragaloside IV (0.73) and astragaloside II (0.81). The study combined fingerprinting with QAMS to improve the quality control standard for RA.

Current advances in screening for bioactive components from medicinal plants by affinity ultrafiltration mass spectrometry

INTRODUCTION

Medicinal plants have played an important role in maintaining human health for thousands of years. However, the interactions between the active components in medicinal plants and some certain biological targets during a disease are still unclear in most cases.

OBJECTIVE

To conduct the high-throughput screening for small active molecules that can interact with biological targets, which is of great theoretical significance and practical value.

METHODOLOGY

The ultrafiltration mass spectrometry (UF-LC/MS) is a powerful bio-analytical method by combining affinity ultrafiltration and liquid chromatography-mass spectrometry (LC/MS), which could rapidly screen and identify small active molecules that bind to biological targets of interest at the same time. Compared with other analytical methods, affinity UF-LC/MS has the characteristics of fast, sensitive and high throughput, and is especially suitable for the complicated extracts of medicinal plants.

RESULTS

In this review, the basic principle, characteristics and some most recent challenges in UF-LC/MS have been demonstrated. Meanwhile, the progress and applications of affinity UF-LC/MS in the discovery of the active components from natural medicinal plants and the interactions between small molecules and biological target proteins are also briefly summarised. In addition, the future directions for UF-LC/MS are also prospected.

CONCLUSION

Affinity UF-LC/MS is a powerful tool in studies on the interactions between small active molecules and biological protein targets, especially in the high-throughput screening of active components from the natural medicinal plants.

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.

An ultrafiltration and high performance liquid chromatography coupled with diode array detector and mass spectrometry approach for screening and characterizing thrombin inhibitors from Rhizoma Chuanxiong

Thrombin (THR) plays a significant role in thromboembolic diseases, direct THR inhibitors are a class of important clinical anticoagulant drugs. This study established a THR in-solution based biospecific extraction combined with ultrafiltration and high performance liquid chromatography coupled with diode array detector and mass spectrometry analysis (TUA) method to screen and identify ligands for THR in Rhizoma Chuanxiong. After evaluating the reliability of the present TUA method using positive (argatroban) and negative (adenosine, tirofiban, ticagrelor) control drugs, this method was successfully applied to detect eight potential active compounds in Rhizoma Chuanxiong. Two new THR-targeted compounds isochlorogenic acid C and senkyunolide I with high THR inhibitory activity (IC50 206.48 and 197.23μM, respectively) were identified by liquid chromatography/mass spectrometry and enzyme inhibitory activity test finally. They were reported with direct THR inhibition activity for the first time and their ligand-THR interactions were explored by in silico molecular docking research. In addition, based on the TUA screening result, four compounds gained similar structure with the two hit compounds were also investigated as promising candidates targeting THR with high binding energy (>5.0kcal/mol). These results may prove that the proposed method could effectively screen THR inhibitors in complex mixtures.

Rapid Screening of Potential Phosphodiesterase Inhibitors from the Roots of Ilex pubescens Hook. et Arn. Using a Combination of Ultrafiltration and LC-MS

The cyclic nucleotide phosphodiesterase (PDE) plays an important role in regulating the levels of second messenger molecules cAMP and cGMP. Various PDE inhibitors have been successfully developed into drugs for targeted diseases. In addition, PDE inhibitors can also be found in different foods and natural medicines. In this study, ultrafiltration liquid chromatography-diode-array detector-electrospray ionization-ion-trap-time-of-flight-mass spectrometry (ultrafiltration LC-DAD-ESI-IT-TOF-MS) was applied to screen PDE inhibitors from the roots of Ilex pubescens Hook. et Arn. As a result, 11 major compounds were identified in I. pubescens roots, with nine compounds as potential PDE inhibitors, among which five were further confirmed to be active against PDEI and PDE5A dose-dependently in vitro, with ilexsaponin A1 and ilexsaponin B2 being the strongest. HPLC quantification of these bioactive compounds suggested that they are major components in the plant. The results demonstrate that ultrafiltration LC-DAD-ESI-IT-TOF-MS is an efficient method for rapid screening of PDE inhibitors from natural medicines.

Facilitated Visual Interpretation of Scores in Principal Component Analysis by Bioactivity-Labeling of 1H-NMR Spectra-Metabolomics Investigation and Identification of a New α-Glucosidase Inhibitor in Radix Astragali

Radix Astragali is a component of several traditional medicines used for the treatment of type 2 diabetes in China. Radix Astragali is known to contain isoflavones, which inhibit α-glucosidase in the small intestines, and thus lowers the blood glucose levels. In this study, 21 samples obtained from different regions of China were extracted with ethyl acetate, then the IC50-values were determined, and the crude extracts were analyzed by 1H-NMR spectroscopy. A principal component analysis of the 1H-NMR spectra labeled with their IC50-values, that is, bioactivity-labeled 1H-NMR spectra, showed a clear correlation between spectral profiles and the α-glucosidase inhibitory activity. The loading plot and LC-HRMS/NMR of microfractions indicated that previously unknown long chain ferulates could be partly responsible for the observed antidiabetic activity of Radix Astragali. Subsequent preparative scale isolation revealed a compound not previously reported, linoleyl ferulate (1), showing α-glucosidase inhibitory activity (IC50 0.5 mM) at a level comparable to the previously studied isoflavones. A closely related analogue, hexadecyl ferulate (2), did not show significant inhibitory activity, and the double bonds in the alcohol part of 1 seem to be important structural features for the α-glucosidase inhibitory activity. This proof of concept study demonstrates that bioactivity-labeling of the 1H-NMR spectral data of crude extracts allows global and nonselective identification of individual constituents contributing to the crude extract's bioactivity.

Pterocarpan scaffold: A natural lead molecule with diverse pharmacological properties

Phytoalexins are substances produced by plants that act as potent inhibitors of pathogens. Pterocarpans are biologically active isoflavonoids most commonly found in the family Fabaceae that have the ability to act as phytoalexins. It is made up of a tetracyclic ring system possessing benzofuran-benzopyran. A very great number of pterocarpans have been isolated from natural sources and they are proved to have significant biological activities such as anti-microbial, anti-cancerous, anti-inflammatory and anti-malarial activities. Recently, pterocarpans gained lot of attention because of the broad range of anti-cancer activities in various cancer cell lines such as breast, leukemia, cervical, lung, colon and melanoma. Interestingly, pterocarpans exhibited inhibitory potency against many enzymes such as PTP1B, Neuraminidase, and α-glycosidase. In addition, they were shown to have anti-estrogenic and anti-diabetic activities. This review is a comprehensive inventory of the structures and sources of pterocarpans and it emphasizes on the biological evaluations of pterocarpans from various plant sources and their scope as a lead molecule.

Screening for the bioactive constituents of traditional Chinese medicines—progress and challenges

The search for lead compounds from traditional Chinese medicines (TCMs) may be promising for new drug development.

Pharmaceutical applications of affinity-ultrafiltration mass spectrometry: Recent advances and future prospects

The immunoaffinity of protein with ligand is broadly involved in many bioanalytical methods. Affinity-ultrafiltration mass spectrometry (AUF-MS), a platform based on interaction of protein-ligand affinity, has been developed to fish out interesting molecules from complex matrixes. Here we reviewed the basics of AUF-MS and its recent applications to pharmaceutical field, i.e. target-oriented discovery of lead compounds from combinatorial libraries and natural product extracts, and determination of free drug concentration in biosamples. Selected practical examples were highlighted to illustrate the advances of AUF-MS in pharmaceutical fields. The future prospects were also presented.

Separation of phenolic acids and flavonoids from Trollius chinensis Bunge by high speed counter-current chromatography

In this work, eleven compounds were successfully separated from Trollius chinensis Bunge by using a two-step high-speed counter-current chromatography (HSCCC) method. NRTL-SAC (nonrandom two-liquid segment activity coefficient) method, a newly developed solvent system selection strategy, was applied to screening the suitable biphasic liquid systems. Hexane/ethyl acetate/ethanol/water (3:7:3:7, v/v) solvent system was used in the first step, while the hexane/ethyl acetate/methanol/water (1:2:1:2, 1:4:1:4, 1:9:1:9, v/v) systems were employed in the second step. The chemical structures of the separated compounds were identified by UV, high resolution ESI-MS and MS/MS data. The separated compounds are 3,4-dihydroxyphenylethanol (1), vanillic acid (2), orientin (3), vitexin (4), veratric acid (5), 2″-O-(3‴, 4‴-dimethoxybenzoyl) orientin (6), 2″-O-feruloylorientin (7), 2″-O-feruloylvitexin (8), 2″-O-(2‴-methylbutyryl) vitexin (9), 2″-O-(2‴-methylbutyryl) isoswertiajaponin (10), 2″-O-(2‴-methylbutyryl) isoswertisin (11). The results demonstrate that HSCCC is a powerful tool for the separation of compounds from extremely complex samples.

High-speed counter-current chromatography coupled online to high performance liquid chromatography-diode array detector-mass spectrometry for purification, analysis and identification of target compounds from natural products

A challenge in coupling high-speed counter-current chromatography (HSCCC) online with high performance liquid chromatography (HPLC) for purity analysis was their time incompatibility. Consequently, HSCCC-HPLC was conducted by either controlling HPLC analysis time and HSCCC flow rate or using stop-and-go scheme. For natural products containing compounds with a wide range of polarities, the former would optimize experimental conditions, while the latter required more time. Here, a novel HSCCC-HPLC-diode array detector-mass spectrometry (HSCCC-HPLC-DAD-MS) was developed for undisrupted purification, analysis and identification of multi-compounds from natural products. Two six-port injection valves and a six-port switching valve were used as interface for collecting key HSCCC effluents alternatively for HPLC-DAD-MS analysis and identification. The ethyl acetate extract of Malus doumeri was performed on the hyphenated system to verify its efficacy. Five main flavonoids, 3-hydroxyphloridzin (1), phloridzin (2), 4',6'-dihydroxyhydrochalcone-2'-O-β-D-glucopyranoside (3, first found in M. doumeri), phloretin (4), and chrysin (5), were purified with purities over 99% by extrusion elution and/or stepwise elution mode in two-step HSCCC, and 25mM ammonium acetate solution was selected instead of water to depress emulsification in the first HSCCC. The online system shortened manipulation time largely compared with off-line analysis procedure and stop-and-go scheme. The results indicated that the present method could serve as a simple, rapid and effective way to achieve target compounds with high purity from natural products.

A simple and sensitive detection of glutamic-pyruvic transaminase activity based on fluorescence quenching of bovine serum albumin

It is well known that Cu(ii) can coordinate withl-alanine (Cu–Ala), which can be destroyed through the addition of glutamic-pyruvic transaminase (GPT) since GPT can effectively catalyze the conversion ofl-alanine into keto-acetic acid.