Recent advances in cell membrane chromatography for traditional Chinese medicines analysis

Identification of N-(((1S,3R,5S)-adamantan-1-yl)methyl)-3-((4-chlorophenyl)sulfonyl)benzenesulfonamide as novel Nav1.8 inhibitor with analgesic profile

Chronic pain is a common and challenging clinical problem that significantly impacts patients' quality of life. The sodium channel Nav1.8 plays a crucial role in the occurrence and development of chronic pain, making it one of the key targets for treating chronic pain. In this article, we combined virtual screening with cell membrane chromatography techniques to establish a novel method for rapid high-throughput screening of selective Nav1.8 inhibitors. Using this approach, we identified a small molecule compound 6, which not only demonstrated high affinity and inhibitory activity against Nav1.8 but also exhibited significant inhibitory effects on CFA-induced chronic inflammatory pain. Compared to the positive drug VX-150, compound 6 showed a more prolonged analgesic effect, making it a promising candidate as a Nav1.8 inhibitor with potential clinical applications. This discovery provides a new therapeutic option for the treatment of chronic pain.

Preparation of antimicrobial peptides and their combination with hydrogels for wound healing applications

The problem of drug resistance caused by long-term use of antibiotics has been a concern for many years. As this problem worsens, there are various bacterial-induced infections that have a serious impact on human health. Currently, antimicrobial peptides are good alternatives to antibiotics, which have powerful antimicrobial activity and unique antimicrobial mechanisms. Developing bacterial resistance is not easy. In addition, how to reduce the production cost of antimicrobial peptides and improve the screening efficiency are the problems that must be solved for antimicrobial peptide application. In this study, we employed cell membrane chromatography linked with the one-bead-one-substance approach to screen and prepare the antimicrobial peptide (SALSP), which offers the benefits of fast synthetic screening and easy operation. Meanwhile, the antimicrobial peptide showed great antimicrobial activity and biocompatibility. We prepared a conjugated sodium alginate/gelatin hydrogel wound dressing incorporating antimicrobial peptides to promote wound healing. In conclusion, this research provides solutions for the development and application of antimicrobial peptides.

Deep simulated annealing for the discovery of novel dental anesthetics with local anesthesia and anti-inflammatory properties

Multifunctional therapeutics have emerged as a solution to the constraints imposed by drugs with singular or insufficient therapeutic effects. The primary challenge is to integrate diverse pharmacophores within a single-molecule framework. To address this, we introduced DeepSA, a novel edit-based generative framework that utilizes deep simulated annealing for the modification of articaine, a well-known local anesthetic. DeepSA integrates deep neural networks into metaheuristics, effectively constraining molecular space during compound generation. This framework employs a sophisticated objective function that accounts for scaffold preservation, anti-inflammatory properties, and covalent constraints. Through a sequence of local editing to navigate the molecular space, DeepSA successfully identified AT-17, a derivative exhibiting potent analgesic properties and significant anti-inflammatory activity in various animal models. Mechanistic insights into AT-17 revealed its dual mode of action: selective inhibition of NaV1.7 and 1.8 channels, contributing to its prolonged local anesthetic effects, and suppression of inflammatory mediators via modulation of the NLRP3 inflammasome pathway. These findings not only highlight the efficacy of AT-17 as a multifunctional drug candidate but also highlight the potential of DeepSA in facilitating AI-enhanced drug discovery, particularly within stringent chemical constraints.

Establishment of Polydopamine-Modified HK-2 Cell Membrane Chromatography and Screening of Active Components from Plantago asiatica L

Cell membrane chromatography (CMC) has been widely recognized as a highly efficient technique for in vitro screening of active compounds. Nevertheless, conventional CMC approaches suffer from a restricted repertoire of cell membrane proteins, making them susceptible to oversaturation. Moreover, the binding mechanism between silica gel and proteins primarily relies on intermolecular hydrogen bonding, which is inherently unstable and somewhat hampers the advancement of CMC. Consequently, this investigation aimed to establish a novel CMC column that could augment protein loading, enhance detection throughput, and bolster binding affinity through the introduction of covalent bonding with proteins. This study utilizes polydopamine (PDA)-coated silica gel, which is formed through the self-polymerization of dopamine (DA), as the carrier for the CMC column filler. The objective is to construct the HK-2/SiO2-PDA/CMC model to screen potential therapeutic drugs for gout. To compare the quantity and characteristics of Human Kidney-2 (HK-2) cell membrane proteins immobilized on SiO2-PDA and silica gel, the proteins were immobilized on both surfaces. The results indicate that SiO2-PDA has a notably greater affinity for membrane proteins compared to silica gel, resulting in a significant improvement in detection efficiency. Furthermore, a screening method utilizing HK-2/SiO2-PDA/CMC was utilized to identify seven potential anti-gout compounds derived from Plantago asiatica L. (PAL). The effectiveness of these compounds was further validated using an in vitro cell model of uric acid (UA) reabsorption. In conclusion, this study successfully developed and implemented a novel CMC filler, which has practical implications in the field.

Pseudo-allergic reactions induced by Chinese medicine injections: a review

Traditional Chinese medicine injections (TCMIs) is a new dosage form of Chinese medicine, which plays a unique role in rescuing patients with critical illnesses that are difficult to replace. With the rapid development and widespread application of TCMIs in recent years, their adverse events have emerged and attracted much attention. Among them, pseudo-allergic reactions, i.e., the most significant adverse reactions occurring with the first dose without immunoglobulin E mediated conditions. Currently, studies on the types of TCMIs and antibiotic mechanisms that cause pseudo-allergic reactions are incomplete, and standard models and technical guidelines for assessing TCMIs have not been established. First, this review describes the causes of pseudo-allergic reactions, in which the components and structures responsible for pseudo-allergic reactions are summarized. Second, the mechanisms by which pseudo-allergic reactions are discussed, including direct stimulation of mast cells and complement activation. Then, research models of pseudo-allergic reaction diseases are reviewed, including animal models and cellular models. Finally, the outlook and future challenges for the development of pseudo-allergic reactions in traditional Chinese medicine (TCM) are outlined. This shed new light on the assessment and risk prevention of pseudo-allergic reactions in TCM and the prevention of clinical adverse reactions in TCM.

Rapid screening and identification of superoxide dismutase activators from traditional Chinese medicines based on affinity ultrafiltration mass chromatography combined with molecular docking

In the present study, a comprehensive strategy integrating affinity ultrafiltration high-performance liquid chromatography quadrupole-time-of-flight mass spectrometry (UF-HPLC-Q-TOF-MS), in silico molecular docking and bioassays was established to rapidly screen natural SOD activators from traditional Chinese medicines. As illustrative case studies, Schisandra chinensis, Fructus cnidii and Radix ophiopogonis were chosen to develop and verify the strategy. The HPLC-Q-TOF-MS was used to identify the compounds in comparison with reference standards and literature data. A total of eight compounds, including four biphenyl-cyclooctene ligands from Schisandra chinensis and four coumarins from Fructus cnidii, were found to potentially increase SOD activities. No ligands were found in the extract of Radix ophiopogonis. Then, in silico molecular docking was performed to investigate the binding site and binding affinity of the candidates on SOD. Compared to the nonspecific ligands screened from the extract, the specific ligands presented stronger binding affinities. In addition, the activity and kinetic parameters of the SOD-ligand were investigated through an improved pyrogallol autoxidation method. Gomisin J and xanthotoxin showed a stronger ability to increase SOD activities. The present study indicated that combining UF-HPLC-Q-TOF-MS and in silico molecular docking offers a powerful and meaningful tool to rapidly screen SOD activators from traditional Chinese medicines.

Mollugin activates GLP-1R to improve cognitive dysfunction in type 2 diabetic mice

AIMS

The incidence of diabetic cognitive dysfunction is increasing year by year, and it has gradually become a research hot spot. Studies have shown that glucagon-like peptide-1 receptor (GLP-1R) agonists can improve cognitive dysfunction in diabetic patients. This study focuses on whether small molecule GLP-1R agonists from traditional Chinese medicine (TCM) can improve the diabetic cognitive dysfunction.

MATERIALS AND METHODS

The small molecules from TCM were screened by cell membrane chromatography (CMC) with GLP-1R-HEK293 cell membrane column. MTT assay, flow cytometry, immunofluorescence cytochemistry and other methods were used to determine the effects of mollugin on the apoptosis rate and reactive oxygen species (ROS) level of high glucose (HG)/hydrogen peroxide (H2O2) induced PC12 cells. Real-Time PCR was used to detect mRNA expression in mouse cerebral cortex. Water maze test was further used to confirm the effect of mollugin on cognitive dysfunction in T2DM mice.

KEY FINDINGS

Mollugin bound to GLP-1R, promoted Ca2+ influx, increased insulin secretion and cAMP content in β-TC-6 cells. Mollugin enhanced the cell viability, ameliorated apoptosis, reduced intracellular ROS levels in HG/H2O2-injured PC12 cells. Mollugin reduced the T2DM mice's escape latency, improved neuronal cell damage, decreased the expression of Pik3ca, Akt1 and Mapk1 mRNA in the cerebral cortex tissue.

SIGNIFICANCE

The results suggest that mollugin could improve cognitive dysfunction in T2DM mice through activating GLP-1R/cAMP/PKA signal pathway.

Traditional uses, phytochemistry, pharmacology, and pharmacokinetics of the root bark of Paeonia x suffruticosa andrews: A comprehensive review

ETHNOPHARMACOLOGICAL RELEVANCE

Moutan Cortex (MC), commonly known as "Mu dan pi", refers to the dried root bark of Paeonia x suffruticosa Andrews and is broadly used as a traditional herbal medication in China, Japan, and Korea. For thousands of years, it has been utilized to treat female genital, extravasated blood, cardiovascular, and stagnant blood disorders.

AIM OF THE REVIEW

The purpose of this review article was to summarize information on the traditional uses, phytochemistry, pharmacology and pharmacokinetics of MC, as well as to outline the further research directions for the development of new drugs and the associations between traditional uses and pharmacological effects.

MATERIALS AND METHODS

The information involved in the study was gathered from a variety of electronic resources, including PubMed, Web of Science, ScienceDirect, SciFinder, China Knowledge Resource Integrated Database, and Google Scholar. The date was from 1992 to 2022.

RESULTS

Approximately 163 chemical compounds have been extracted and identified from MC, including monoterpenes, monoterpene glycosides, triterpenes, phenolics, flavonoids, volatile oils, alkaloids, and others. In these categories, the monoterpene glycosides and phenols being the most common. A wide variety of pharmacological effects have been described for MC crude extracts and active molecules, such as antioxidant, anti-inflammatory, antibacterial and antiviral, antitumor, antidiabetic, organ protection, and neuroprotective activities, as well as treating cardiovascular diseases. Pharmacokinetics has been also used in the study of MC, including its crude extracts or chemical constituents, in order to explore the therapeutic mechanism, direct clinically appropriate application and provide new ideas for the exploitation of innovative medicines.

CONCLUSION

Modern pharmacological research has demonstrated that MC, as a significant therapeutic resource, has the ability to heal a wide range of diseases, particularly female genital and cardiovascular problems. These researches propose therapeutic ideas for the development of novel MC medicines. Furthermore, preclinical and clinical study have verified several observed pharmacological properties related with the traditional usages of MC.

Isolation and identification of angiogenesis-promoting components in Huanglian Jiedu decoction using live cell bio-specific extraction

ETHNOPHARMACOLOGICAL RELEVANCE

Huanglian Jiedu Decoction (HLJDD) is a traditional heat-dissipating and detoxicating prescription used in Chinese medicine and has been extensively applied in the clinical treatment of ischemic stroke. Preliminary research confirmed that HLJDD exerts a neuroprotective effect on brain tissue injury caused by cerebral ischemia by promoting angiogenesis. However, the components of HLJDD responsible for its medicinal activity in ischemic injury remain unclear.

AIM OF THE STUDY

The aim of this study was to identify the active components of HLJDD that could promote angiogenesis and investigate its underlying mechanism, as well as Hypoxia-inducible factor-1α (HIF-1α)/Vascular endothelial growth factor (VEGF) signalings in human umbilical vein endothelial cells (HUVECs).

MATERIALS AND METHODS

The specific binding components of HLJDD with HUVECs were isolated and identified through a combination of live cell biospecific extraction, solid-phase extraction, and ultra performance liquid chromatography (UPLC)-Orbitrap Fusion Tribrid mass spectrometry (MS). Their pharmacological activity against oxygen-glucose deprivation-reperfusion (OGD/R) injury and in vitro pro-angiogenesis was validated using Cell Counting Kit-8 (CCK-8) and tube formation analysis, respectively. Finally, we explored the effect of active ingredients on the expression levels of HIF-1α and VEGF using enzyme-linked immunosorbent assay. Molecular docking was used to predict the potential binding of six active components to phosphoinositide 3-kinase (PI3K), serine/threonine-specific protein kinase (AKT) and Von Hippel-Lindau (VHL) proteins, which are involved in the regulation of HIF-1α and are highly associated with angiogenesis.

RESULTS

A total of 13 HUVECs-specific HLJDD components were identified, and 10 of them were shown to protect against OGD/R injury. We were the first to demonstrate that two of these components have a protective role in OGD/R-induced HUVECs injury. Additionally, seven of these 10 components exhibited angiogenesis-promoting activity, and two of these components were shown, for the first time, to promote angiogenesis in HUVECs. These effects might occur through the HIF-1α/VEGF pathway. Molecular docking results showed that all six active ingredients could stably bind to PI3K and AKT proteins, suggesting that these two proteins may be potential targets for six active ingredients.

CONCLUSIONS

The approach employed in this study effectively identified proangiogenic components in HLJDD that might act via PI3K/AKT/HIF-1α/VEGF pathways and other mechanisms involved in angiogenesis. In conclusion, this study was the first to demonstrate four compounds with new bioactivities and could also provide insight into the isolation and discovery of new bioactive compounds existing in Chinese medicine with potential clinical value.

Chitosan-based matrix solid-phase dispersion extraction assisted cell membrane magnetic bead ligand-affinity assay for screening active compounds from Fructus Cnidii

Cell membrane ligand-affinity assay is a useful tool for screening the active compounds from natural products. However, in traditional cell membrane ligand-affinity assays, natural products need to be refluxed, before being analyzed. This process consumes considerable time and energy and cannot be used for screening natural products that contain thermally unstable compounds. Therefore, an efficient analytical method is required. In this study, chitosan-based matrix solid-phase dispersion extraction was combined with cell membrane magnetic bead ligand-affinity assay to form a novel method for identifying the active compounds in Fructus Cnidii such as osthole and imperatorin. When compared with traditional cell membrane ligand-affinity assays, this assay requires less energy, extraction time (7 min), solvent volume (1.2 mL) and fewer natural products (40 mg). This indicates that the chitosan-based matrix solid-phase dispersion extraction assisted cell membrane magnetic beads ligand-affinity assay is an alternative analytical method for studying natural products. This article is protected by copyright. All rights reserved.

Application progress of immobilized biomembrane in the discovery of active compounds of natural products

Natural products (NPs) are an important source of bioactive compounds. Considering their complex matrix effects, the development of suitable methodologies for the fast identification and analysis of active substances from NPs played a significant role in controlling their quality and discovering new drugs. In recent years, the technology of immobilized biomembrane has attracted increasing attention, due to its peculiarities such as multi-target efficiency, accuracy and/or time-saving compared with traditional activity-guided separation and ligand fishing methods. This article first provides a systematic review of the latest advances in screening technologies based on biomembrane in the field of NPs. It includes detailed discussions of these technologies, including cell membrane chromatography, artificial membrane chromatography, cell membrane fishing, living cell fishing methods, and their applications in screening various active molecules from NPs. Their limitations and future development prospects were further discussed.

In situ synthesis and unidirectional insertion of membrane proteins in liposome-immobilized silica stationary phase for rapid preparation of microaffinity chromatography

Cell membrane affinity chromatography has been widely applied in membrane protein (MP)-targeted drug screening and interaction analysis. However, in current methods, the MP sources are derived from cell lines or recombinant protein expression, which are time-consuming for cell culture or purification, and also difficult to ensure the purity and consistent orientation of MPs in the chromatographic stationary phase. In this study, a novel in situ synthesis membrane protein affinity chromatography (iSMAC) method was developed utilizing cell-free protein expression (CFE) and covalent immobilized affinity chromatography, which achieved efficient in situ synthesis and unidirectional insertion of MPs into liposomes in the stationary phase. The advantages of iSMAC are: 1) There is no need to culture cells or prepare recombinant proteins; 2) Specific and purified MPs with stable and controllable content can be obtained within 2 h; 3) MPs maintain the transmembrane structure and a consistent orientation in the chromatographic stationary phase; 4) The flexible and personalized construction of cDNAs makes it possible to analyze drug binding sites. iSMAC was successfully applied to screen PDGFRβ inhibitors from Salvia miltiorrhiza and Schisandra chinensis. Micro columns prepared by in-situ synthesis maintain satisfactory analysis activity within 72 h. Two new PDGFRβ inhibitors, salvianolic acid B and gomisin D, were screened out with K_D values of 13.44 and 7.39 μmol/L, respectively. In vitro experiments confirmed that the two compounds decreased α-SMA and collagen Ӏ mRNA levels raised by TGF-β in HSC-T6 cells through regulating the phosphorylation of p38, AKT and ERK. In vivo, Sal B could also attenuate CCl₄-induced liver fibrosis by downregulating PDGFRβ downstream related protein levels. The iSMAC method can be applied to other general MPs, and provides a practical approach for the rapid preparation of MP-immobilized or other biological solid-phase materials.

Bioactivity-guided isolation of cyclooxygenase-2 inhibitors from Saussurea obvallata (DC.) Edgew. Using affinity solid phase extraction assay

ETHNOPHARMACOLOGICAL RELEVANCE

Saussurea obvallata (DC.) Edgew. is a traditional Tibetan medicine used for the treatment of inflammation-related diseases, but the scientific validation was very limited.

AIM OF THE STUDY

This study aimed to rapid screen and targeted isolate cyclooxygenase-2 (COX-2) inhibitors from S. obvallata extract.

MATERIALS AND METHODS

An efficient ligand-fishing method based on affinity solid phase extraction (A-SPE) combining with HPLC was developed. The identified COX-2 inhibitors were separated using preparative liquid chromatography. In vitro COX-2 inhibition assays were employed to confirm the inhibitory activities of the isolated compounds. In addition, the effect of the isolated compounds on the production of prostaglandin E2 (PGE2) and the expression of COX-2 in LPS-induced RAW 264.7 were evaluated.

RESULTS

A total of four phenylpropanoids, isolariciresinol, syringaresinol, pinoresinol and balanophonin were targeted isolated as COX-2 inhibitors with IC₅₀ values of 36.4 ± 2.6 μM, 23.1 ± 1.8 μM, 3.6 ± 0.3 μM and 12.1 ± 0.9 μM, respectively. The isolated compounds significantly inhibited LPS-induced NO production in a dose-dependent manner. And, the results of the inhibitory effect on the release of PGE₂ and the expression of COX-2 in LPS-induced macrophages were consistent with A-SPE analysis.

CONCLUSION

The present work demonstrated that the developed A-SPE-HPLC method could successfully targeted isolated COX-2 inhibitors from S. obvallata extract. And, the isolation results indicated that the therapeutic effect of S. obvallata on inflammation-related diseases was partly based on the COX-2 active ingredients.

Screening S protein - ACE2 blockers from natural products: Strategies and advances in the discovery of potential inhibitors of COVID-19

The Coronavirus disease, 2019 (COVID-19) is caused by severe acute respiratory syndrome Coronavirus 2 (SARS-CoV-2), which poses a major threat to human life and health. Given its continued development, limiting the spread of COVID-19 in the population remains a challenging task. Currently, multiple therapies are being tried around the world to deal with SARS-CoV-2 infection, and a variety of studies have shown that natural products have a significant effect on COVID-19 patients. The combination of SARS-CoV-2 S protein with Angiotensin converting enzyme II(ACE2) of host cell to promote membrane fusion is an initial critical step for SARS-CoV-2 infection. Therefore, screening natural products that inhibit the binding of SARS-CoV-2 S protein and ACE2 also provides a feasible strategy for the treatment of COVID-19. Establishment of high throughput screening model is an important basis and key technology for screening S protein-ACE2 blockers. Based on this, the molecular structures of SARS-CoV-2 and ACE2 and their processes in the life cycle of SARS-CoV-2 and host cell infection were firstly reviewed in this paper, with emphasis on the methods and techniques of screening S protein-ACE2 blockers, including Virtual Screening (VS), Surface Plasmon Resonance (SPR), Biochromatography, Biotin-avidin with Enzyme-linked Immunosorbent assay and Gene Chip Technology. Furthermore, the technical principle, advantages and disadvantages and application scope were further elaborated. Combined with the application of the above screening technologies in S protein-ACE2 blockers, a variety of natural products, such as flavonoids, terpenoids, phenols, alkaloids, were summarized, which could be used as S protein-ACE2 blockers, in order to provide ideas for the efficient discovery of S protein-ACE2 blockers from natural sources and contribute to the development of broad-spectrum anti coronavirus drugs.

Rapidly identifying bioactive compounds from Zhisou oral liquid by immobilized receptor-based high-performance affinity chromatography

The identification of bioactive compounds in complex matrices remains a major challenge due to the lack of highly efficient and specific methods. This work developed an approach based on high-performance affinity chromatography to identify the potential antitussive compounds from Zhisou oral liquid . The main methods include the synthesis of immobilized beta2-adrenoceptor by a one-step method, the screening and identification of the potential bioactive compounds by the receptor column coupled with mass spectrometry, and the binding mechanism analysis of the compounds to the receptor by the in vivo experiment, injection amount dependent method and molecular simulation. We identified the potential bioactive compounds of Zhisou oral liquid as glycyrrhizic acid, platycodin D, tuberostemonine, and hesperidin. In vivo experiment showed that the combinational utilization of the four compounds was possible to present an equivalent antitussive effect to the formula. The docking results demonstrated that hydrogen bonds and Van der Waals forces were the main forces to drive the binding of the four compounds to beta2-adrenoceptor. We concluded that the four compounds are the effective components in Zhisou oral liquid. The proposed strategy is possible to provide an alternative for the development of highly efficient methods to pursue the bioactive compounds of complex matrices.

Advances and applications of in-tube solid-phase microextraction for analysis of proteins

In-tube solid-phase microextraction (IT-SPME) with capillary column as extraction device is a well-established green extraction technique with a lot of applications in the fields of biomedicine, food and environment. This article reviews the research contributions of IT-SPME for analysis of proteins. The paper first briefly describes the history of IT-SPME. Then, the development and principle of IT-SPME for analysis of proteins are introduced, in which capillary column configurations of IT-SPME and instruments for quantitative analysis of proteins are summarized. Subsequently, the synthesis strategy and recognition principle of different recognition units, including antibodies, aptamers, molecularly imprinted polymers, and boronate affinity materials, are discussed in detail. This part also introduces several rare recognition units, including lectins, restricted access materials, lysine modified with β-cyclodextrin and cell membrane. The development trend and possible future direction of IT-SPME for analysis of proteins are mentioned.

Advances in cell membrane chromatography

Cell membrane chromatography (CMC) is a biomimetic chromatographic method based on the ability of membrane receptors to selectively interact with their ligands in vivo. Using membrane receptors as a stationary phase, the CMC method helps in determining the binding characteristics between ligands and membrane receptors and in efficiently identifying specific target components in a complex sample that produce the cellular biological effects of ligands (drugs, antibodies, enzymes, cytokines, etc.). CMC is an analytical tool for revealing characteristics of ligand-receptor interactions, screening and discovering target substances, and accurately controlling the quality of drugs. Since establishment of CMC in the early 1990s, with the rapid development of cell biology, significant progress has been made in the development of high-expression receptors, engineered cell cultures, and standardized preparations, which allowed in vitro immobilization of cell membrane receptors and miniaturization of binding assays. A variety of CMC models have been established using different membrane receptors as a stationary phase, and many new methods have been developed by combining CMC with high-performance liquid chromatography (HPLC)/mass spectrometry or HPLC-IT-TOF technologies. CMC methods have been widely used to study drug-receptor interactions and to screen complex samples for effective or harmful components.

Characterization of interactions between local anesthetics and histamine H1 receptor by cell membrane chromatography model

Local anesthetic has a wide application in clinical practice. However, angioedema, an adverse reaction caused by local anesthetics, has been reported to be related to histamine H₁ receptor (H₁R). Hence, an effective and practical method for investigating the interaction characteristics between local anesthetics and H₁R is needed. In this work, the competition binding assay and the relative standard method based on H₁R-HEK293/cell membrane chromatography (CMC) were developed to analyze the equilibrium dissociation constant (K_D) values of local anesthetics with H₁R. The activity of drugs toward H₁R was evaluated by intracellular Ca²⁺ imaging assay. Molecular docking was used to verify the interaction modes that occurred at the activate pocket of H₁R protein. Results showed that the local anesthetics can directly occupy histamine binding sites on H₁R, and the K_D values obtained from different CMC methods exhibited positive correlations with each other (p < 0.01). The K_D values of tetracaine, procaine, and lidocaine were much closer to that of histamine than bupivacaine and ropivacaine. This was not only in line with the Ca²⁺ responses in activating H₁R, but also consistent with the same amino acid residues shared with histamine in the H₁R active site. In conclusion, this study provided new insight into the interactions between local anesthetics and H₁R. The H₁R-HEK293/CMC methods developed in this study could be used to evaluate the interaction characteristics of those compounds acting on H₁R.

Screening active components from Rubus amabilis for pancreatic β-cells protection

CONTEXT

Rubus species (Rosaceae) have been used in folk medicine to treat diabetes due to their hypoglycaemic activity.

OBJECTIVE

To screen the active components that act as hypoglycaemic agents in Rubus amabilis Focke and the underlying mechanisms.

MATERIALS AND METHODS

Aqueous stem extract of R. amabilis was incubated with MIN6 β-cells, PBS was used as the blank control. Then the cells were washed, cell membrane-bound components were dissociated and identified by UPLC/MS. Total procyanidins (PCs) in R. amabilis was enriched and the cytotoxicity and anti-proliferation on β-cell were evaluated by MTT assay. PCs at 25, 50, and 75 μg/mL was applied for 24 h to determine its effects on palmitate (PA)-induced apoptosis and GSIS. Western blotting was employed to detect the protein expression of PI3K/Akt/FoxO1 signalling. The antioxidant indices were also measured.

RESULTS

β-Cell membrane-bound components were identified as three procyanidin B dimers and a C trimer. PCs showed no significant cytotoxicity up to a concentrations of 100 μg/mL. PCs treatment reversed the elevated apoptosis rate and impaired GSIS induced by PA. PCs markedly decreased the intracellular ROS and MDA production and increased the SOD activity. Moreover, PCs promoted the phosphorylation of Akt and FoxO1, and regulated Pdx-1 and Bax expression in MIN6 cells. Discussion and conclusion: The active components that act as hypoglycaemic agents in R. amabilis are procyanidins, which protected MIN6 cells against PA-induced apoptosis by activating PI3K/Akt/FoxO1 signalling. These results indicate that β-cell extraction, combined with UPLC/MS, is a valid method for screening antidiabetic components from herbal medicines.

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.

Recent advances in screening active components from natural products based on bioaffinity techniques

Natural products have provided numerous lead compounds for drug discovery. However, the traditional analytical methods cannot detect most of these active components, especially at their usual low concentrations, from complex natural products. Herein, we reviewed the recent technological advances (2015–2019) related to the separation and screening bioactive components from natural resources, especially the emerging screening methods based on the bioaffinity techniques, including biological chromatography, affinity electrophoresis, affinity mass spectroscopy, and the latest magnetic and optical methods. These screening methods are uniquely advanced compared to other traditional methods, and they can fish out the active components from complex natural products because of the affinity between target and components, without tedious separation works. Therefore, these new tools can reduce the time and cost of the drug discovery process and accelerate the development of more effective and better-targeted therapeutic agents.

Covalent Design of Cell Membrane Stationary Phase with Enhanced Stability for Fast Screening P-Glycoprotein Inhibitors

Cell membrane chromatography (CMC) has been widely used for characterizing the interaction between drugs and membrane receptors to screen target components from herbal medicines. However, the column life, stability, and the efficiency cannot meet the needs of high-throughput screening purpose. In this study, a P-glycoprotein immobilized cell membrane stationary phase (P-gp/CMSP) was prepared with a simple and mild two-step aldehyde modification, realizing the covalent bonding between cell membrane and stationary phase. The column life and stability were significantly enhanced compared with the unmodified columns. The P-gp/CMC column was equipped into a comprehensive 2D P-gp/CMC/Capcell-C18/TOFMS system, which actualizes the automated and high-throughput analytical process and rapid identification of complex chemical samples with no data loss. Five compounds with significant retention were screened out and unambiguously identified by the comprehensive 2D analytical system. Baicalin was confirmed as a P-gp inhibitor with ATP depletion inhibition ratio of 83.4%. Moreover, the reversal index of baicalin on DOX significantly increased to 11.13 when its concentration reached 25 μM, revealing that baicalin could effectively reverse the MDR cell model induced by DOX. The integrated system is a practical drug discovery platform and could be applied to other transmembrane protein models.

Stepwise rapid tracking strategy to identify active molecules from Ixeris sonchifolia Hance based on "'affinity mass spectrometry-atomic force microscopy imaging'" technology

In this study, a novel stepwise rapid tracking strategy was reported to identify the active molecules from Ixeris sonchifolia Hance (IsH) in the treatment of coronary heart disease (CHD) based on "affinity mass spectrometry (MS)-atomic force microscopy (AFM) imaging" technology. First, vascular endothelial growth factor receptor 2 (VEGFR2) of the vascular endothelial growth factor (VEGF) signal transduction pathway located on the cell membrane was revealed to be the core target protein in CHD treatment through network pharmacology and bioinformatics. In addition, affinity MS screening based on VEGFR2 identified isochlorogenic acid A and luteolin-7-O-glucuronide as having stronger affinity with VEGFR2. Then, the active molecule was elucidated based on the observation that its actions accompanied the molecular morphological changes by AFM imaging and it could act on the binding pocket of VEGFR2 through molecular docking which further demonstrated the analysis and inference of AFM imaging. The methyl thiazolyl tetrazolium (MTT) assay finally confirmed that the active molecules specifically combined with the potential core target protein to protect the viability of cardiomyocytes, which identified the main potential active molecules in IsH for the treatment of CHD and provided a possible mechanism for the protective role of the drug. The technology established in this study could facilitate the rapid tracing of potential active molecules in traditional Chinese medicine (TCM), which would provide further a reference for research on quality, molecular mechanisms and new drugs.

Development of an immobilized liposome chromatography method for screening and characterizing α-glucosidase-binding compounds

Immobilized liposome chromatography (ILC) is a powerful tool in screening and analyzing membrane-permeable components in natural medicinal herbs. In this study, the stationary phase of a new receptor liposome biomembrane chromatography (RLBC) was employed to screen the active ingredients in seven natural medicinal herbs. As a model system, α-glucosidase was immobilized in porous silica gel by incorporating α-glucosidase into liposome vesicles. Combined with HPLC, this stationary phase can be used to evaluate the interaction of liposome-protein compounds with compounds and drugs. The surface characteristics of the RLBC phase was characterized by Scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR) and Energy dispersive spectrometer (EDS). RLBC was successfully used to screen and analyze permeable compounds in natural medicinal herbs, and screen the extracts from Schisandra chinensis. This method was used to establish that Schisandrin in Schisandra chinensis is an active component. Furthermore, the hypoglycemic effect of Schisandrin was verified in vivo in rats. This study further modeled the relationship between the activity of inhibitor and retention behavior with RLBC with a mathematical equation. RLBC stationary phase combined with HPLC can be used for rapid screening of drug candidates.

Anti-pseudo-allergic capacity of alkaloids screened from Uncaria rhynchophylla

Two alkaloids were screened from Uncaria rhynchophylla (UR) by MRGPRX2-HEK293/CMC model and showed anti-pseudo-allergic effects in vivo and in vitro, which may provide evidence for anti-pseudo-allergic effects and bioactivity development of UR.

Exploring a New Natural Treating Agent for Primary Hypertension: Recent Findings and Forthcoming Perspectives

Primary hypertension describes abnormally-high systolic/diastolic blood pressure in a resting condition caused by various genetic or environmental risk factors. Remarkably, severe complications, such as ischemic cardiovascular disease, stroke, and chronic renal disease have led to primary hypertension becoming a huge burden for almost one-third of the total population. Medication is the major regimen for treating primary hypertension; however, recent medications may have adverse effects that attenuate energy levels. Hence, the search for new hypotensive agents from folk or traditional medicine may be fruitful in the discovery and development of new drugs. This review assembles recent findings for natural antihypertensive agents, extracts, or decoctions published in PubMed, and provides insights into the search for new hypotensive compounds based on blood-pressure regulating mechanisms, including the renin-angiotensin-aldosterone system and the sympathetic/adrenergic receptor/calcium channel system.

Recent applications of immobilized biomaterials in herbal analysis

Immobilization of biomaterials developed rapidly due to the great promise in improving their stability, activity and even selectivity. In this review, the immobilization strategies of biomaterials, including physical adsorption, encapsulation, covalent attachment, cross-linking and affinity linkage, were briefly introduced. Then, the major emphasis was focused on the reported various types of immobilized biomaterials, including proteins, enzymes, cell membrane and artificial membrane, living cells, carbohydrates and bacteria, used in the herbal analysis for bioactive compound screening, drug-target interaction evaluation and chiral separation. In addition, a series of carrier materials applied in biomaterials immobilization, such as magnetic nanoparticles, metal-organic frameworks, silica capillary column, cellulose filter paper, cell membrane chromatography, immobilized artificial membrane chromatography and hollow fiber, were also discussed. Perspectives on further applications of immobilized biomaterials in herbal analysis were finally presented.

Screening potential antagonists of epidermal growth factor receptor from Marsdenia tenacissima via cell membrane chromatography model assisted by HPLC-ESI-IT-TOF-MS

Marsdenia tenacissima, or Tongguanteng in Chinese, is a traditional Chinese herb and has a broad application in clinical practice for its pharmacological effects of treating asthma, pneumonia, tonsillitis, pharyngitis tumors, etc. However, few studies have reported the screening of the active components of this medicine for tumor therapy. In this work, a two-dimensional analytical system was developed to screen antagonists of epidermal growth factor receptor (EGFR) from M. tenacissima. A fraction was retained on the EGFR cell membrane chromatography (CMC) column, separated and identified as tenacissoside G (TG), tenacissoside H (TH) and tenacissoside I (TI) by two-dimensional HPLC-IT-TOF-MS. Molecular docking and 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay were carried out to assess the activity of TS (including TG, TH and TI). Molecular docking results showed that the binding mode of TS on EGFR is similar to that of gefitinib. The MTT assay demonstrated that gefitinib and TS (especially TI) could inhibit the growth of EGFR highly expressed cell lines in a dose-dependent manner in the range of 5-50 μmol/L. In conclusion, the two-dimensional EGFR/CMC-HPLC-IT-TOF-MS system could be a useful approach in drug discovery from traditional Chinese medicines for searching for potential antitumor candidates.

A strategy for screening bioactive components from natural products based on two-dimensional cell membrane chromatography and component-knockout approach

Cell membrane chromatography (CMC) is a bioaffinity chromatographic method used to screen active compounds from natural products. However, since the receptor capacity of CMC column is limited, high content/affinity compounds may cause column overloading and thus lead to ignorance of other positive candidates. For avoiding this effect and comprehensively discovering bioactive components, a strategy based on two-dimensional CMC and component-knockout approach was proposed. As an illustrative case study, red yeast rice (RYR), a rice product with good myocardial protective effect in clinical studies, was selected as the model experimental sample. For discovering its potential cardioprotective compounds, a CMC model with H9c2 rat cardiac myoblasts (H9c2/CMC) with good selectivity, stability and reproducibility was established. By using two-dimensional H9c2/CMC-HPLC coupled with QTOF MS system, three components were firstly screened out. After knocking out high content/affinity compound, another four bioactive compounds were then found. By this two-round screening, column overloading caused by high concentration or infinity compounds was avoided, and trace compounds were enriched. As a result, one pigment and six monacolins from RYR were fished out. The results indicate the proposed strategy might be used to discover active compounds from complex matrix.

Identification of eupatilin and ginkgolide B as p38 ligands from medicinal herbs by surface plasmon resonance biosensor-based active ingredients recognition system

Screening of bioactive ligands for a certain protein target from medicinal herbs is a highly important yet challenging task during drug discovery process. In this study, a surface plasmon resonance biosensor-based active ingredient recognition system (SPR-AIRS) was applied to screen p38 mitogen-activated protein kinase (p38) ligands from herbal extracts. After p38 protein was immobilized on a SPR chip and the suitability of SPR-AIRS was validated, thirty-four p38-related medicinal herbs were selected and pre-screened. Two medicinal herbs having high response signal with p38-immobilized chip, Folium Ginkgo and Herba Artemisiae Scopariae, were injected into SPR system for ligand fishing. Among them, two active compounds, eupatilin (EPT) and ginkgolide B (GKB), were identified as p38 ligands, and then the K_D values of EPT and GKB were measured as 21.68 ± 2.21 and 44.71 ± 1.80 μM, respectively. They can inhibit p38 activities significantly and bind to the ATP binding site on p38. Furthermore, EPT and GKB can inhibit cell proliferation (IC₅₀ = 30.31 ± 6.84 and 42.97 ± 0.83 μM), induce apoptosis and G2/M cell cycle arrest against K562 cell line. This is the first time that EPT and GKB are reported as effective p38 binding ligands. These results prove that SPR-AIRS could be an effective method to screen active compounds acting on a specific protein from complex systems.

Ligand fishing with cellular membrane-coated cellulose filter paper: a new method for screening of potential active compounds from natural products

Ligand fishing is a widely used approach for screening active compounds from natural products. Recently, cell membrane (CM) as affinity ligand has been applied in ligand fishing, including cell membrane chromatography (CMC) and CM-coated magnetic bead. However, these methods possess many weaknesses, including complicated preparation processes and time-consuming operation. In this study, cheap and easily available cellulose filter paper (CFP) was selected as carrier of CM and used to fabricate a novel CM-coated CFP (CMCFP) for the first time. The type of CFP was optimized according to the amount of immobilized protein, and the immobilization of CM onto CFP by the insertion and self-fusion process was verified by confocal imaging. The CMCFP exhibited good selectivity and stability and was used for fishing potentially active compounds from extracts of Angelica dahurica. Three potentially active compounds, including bergapten, pabulenol, and imperatorin, were fished out and identified. The traditional Chinese medicine systems pharmacology database and analysis platform was used to build an active compound-target protein network, and accordingly, the gamma-aminobutyric acid receptor subunit alpha-1 (GABRA1) was deduced as potential target of CM for the active compounds of Angelica dahurica. Molecular docking was performed to evaluate the interaction between active compounds and GABRA1, and bergapten was speculated as a new potentially active compound. Compared with other methods, the fishing assay based on CMCFP was more effective, simpler, and cheaper.

Screening techniques for the identification of bioactive compounds in natural products

Natural products (NPs) have a long history of clinical use and are rich source of bioactive compounds. The development of tools and techniques for identifying and analyzing NP bioactive compounds to ensure their quality and discover new drugs is thus very important and still in demand. Screening techniques have proven highly useful for screening and analyzing active components in complex mixtures, which rely on cell culture, dialysis, ultrafiltration, chromatographic methods and target molecule immobilization, using biological targets to identify the active compounds. The recent progress in biological screening techniques in the field of natural products is reviewed here. This includes a review on the strategy and application of the screening methods, their detailed description and discussion of their existing limitations of the different models along with prospective in future development of screening techniques.

Study on screening potential allergenic proteins from infant milk powders based on human mast cell membrane chromatography and histamine release assays

Cow's milk allergy is mainly observed in infants and young children. Most allergic reactions affect the skin, followed by the gastrointestinal and respiratory systems. Conventional diagnosis is based on positive allergy studies and evaluation of parameters including IgE and IgG1 levels, acute allergic skin response and anaphylactic shock reactions. We developed a cell membrane chromatographic (CMC) method based on human mast cells (HMC-1) for screening potential allergens in infant formula milk powders (IFMP). HMC-1 cell membranes were extracted and mixed with silica to prepare cell membrane chromatography columns (10 mm × 2 mm i.d., 5 µm). Under the conditions of 0.2 mL/min flow rate and 214 nm detection wavelength, human breast milk showed no retention. However, IFMP showed clear retention. The retained fractions were collected and analyzed through matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS). Four major milk proteins, i.e., α-casein, β-casein, α-lactalbumin, and β-lactoglobulin A, were identified. Furthermore, these proteins and β-lactoglobulin B showed clear retention on HMC-1/CMC columns. To test the degranulation effects of the five proteins, histamine and β-hexosaminidase release assays were carried out. All five proteins induced HMC-1 cells to release histamine and β-hexosaminidase. Also, we established a reversed phase liquid chromatographic (RPLC) method for the determination of the five proteins in IFMP and the results showed that 90% proteins in IFMP were α-casein and β-casein. We concluded that cow's milk proteins may be potential allergens and caseins cause more β-casein allergic risk than other proteins. This conclusion was consistent with other studies.

A method for screening active components from Chinese herbs by cell membrane chromatography-offline-high performance liquid chromatography/mass spectrometry and an online statistical tool for data processing

Cell membrane chromatography (CMC) has been successfully applied to screen bioactive compounds from Chinese herbs for many years, and some offline and online two-dimensional (2D) CMC-high performance liquid chromatography (HPLC) hyphenated systems have been established to perform screening assays. However, the requirement of sample preparation steps for the second-dimensional analysis in offline systems and the need for an interface device and technical expertise in the online system limit their extensive use. In the present study, an offline 2D CMC-HPLC analysis combined with the XCMS (various forms of chromatography coupled to mass spectrometry) Online statistical tool for data processing was established. First, our previously reported online 2D screening system was used to analyze three Chinese herbs that were reported to have potential anti-inflammatory effects, and two binding components were identified. By contrast, the proposed offline 2D screening method with XCMS Online analysis was applied, and three more ingredients were discovered in addition to the two compounds revealed by the online system. Then, cross-validation of the three compounds was performed, and they were confirmed to be included in the online data as well, but were not identified there because of their low concentrations and lack of credible statistical approaches. Last, pharmacological experiments showed that these five ingredients could inhibit IL-6 release and IL-6 gene expression on LPS-induced RAW cells in a dose-dependent manner. Compared with previous 2D CMC screening systems, this newly developed offline 2D method needs no sample preparation steps for the second-dimensional analysis, and it is sensitive, efficient, and convenient. It will be applicable in identifying active components from Chinese herbs and practical in discovery of lead compounds derived from herbs.

Comprehensive two-dimensional APTES-decorated MCF7-cell membrane chromatographic system for characterizing potential anti-breast-cancer components from Yuanhu-Baizhi herbal medicine pair

Rhizoma corydalis and Radix Angelicae Dahurica (Yuanhu–Baizhi) herbal medicine pair has been used for thousands of years and has been reported to be potentially active in recent cancer therapy. But the exact active components or fractions remain unclear. In this study, a new comprehensive two-dimensional (2D) 3-aminopropyltriethoxysilane (APTES)-decorated MCF7-cell membrane chromatography (CMC)/capcell-C18 column/time-of-flight mass spectrometry system was established for screening potential active components and clarifying the active fraction of Yuanhu–Baizhi pair. APTES was modified on the surface of silica, which can provide an amino group to covalently link cell membrane fragments with the help of glutaraldehyde in order to improve the stability and column life span of the MCF7 CMC column. The comprehensive 2D MCF7-CMC system showed good separation and identification abilities. Our screen results showed that the retention components are mainly from the alkaloids in Yuanhu (12 compounds) and the coumarins (10 compounds) in Baizhi, revealing the active fractions of Yuanhu–Baizhi herbal medicine pair. Oxoglaucine, protopine, berberine, osthole, isopimpinellin and palmitic acid were selected as typical components to test the effects on cell proliferation and their IC₅₀ were calculated as 38.17 μM, 29.45 μM, 45.42 μM, 132.7 μM, 156.8 μM and 90.5 μM respectively. Cell apoptosis assay showed that the drug efficacy was obtained mainly through inducing cell apoptosis. Furthermore, a synergistic assay results demonstrated that oxoglaucine (representative of alkaloids from Yuanhu) and isopimpinellin (representative of coumarins from Baizhi) showed significant synergistic efficacy with GFT, indicating that these components may act on other membrane receptors. The proposed 2D CMC system could also be equipped with other cells for further applications. Besides, the follow-up in-vitro experimental strategy using cell proliferation assay, cell apoptosis assay and synergistic assay proved to be a practical way to confirm the active fractions of herbal medicine.

Discovery and evaluation of triple inhibitors of VEGFR-2, TIE-2 and EphB4 as anti-angiogenic and anti-cancer agents

Receptor tyrosine kinases (RTKs), especially VEGFR-2, TIE-2, and EphB4, play a crucial role in both angiogenesis and tumorigenesis. Moreover, complexity and heterogeneity of angiogenesis make it difficult to treat such pathological traits with single-target agents. Herein, we developed two classes of multi-target RTK inhibitors (RTKIs) based on the highly conserved ATP-binding pocket of VEGFR-2/TIE-2/EphB4, using previously reported BPS-7 as a lead compound. These multi-target RTKIs exhibited considerable potential as novel anti-angiogenic and anticancer agents. Among them, QDAU5 displayed the most promising potency and selectivity. It significantly suppressed viability of EA.hy926 and proliferation of several cancer cells. Further investigations indicated that QDAU5 showed high affinity to VEGFR-2 and reduced the phosphorylation of VEGFR-2. We identified QDAU5 as a potent multiple RTKs inhibitor exhibiting prominent anti-angiogenic and anticancer potency both in vitro and in vivo. Moreover, quinazolin-4(3H)-one has been identified as an excellent hinge binding moiety for multi-target inhibitors of angiogenic VEGFR-2, Tie-2, and EphB4.