Structure Characterization of Honey-Processed Astragalus Polysaccharides and Its Anti-Inflammatory Activity In Vitro

Chemical Composition and Therapeutic Effects of Several Astragalus Species (Fabaceae)

The review integrates information on the component composition and biological activity of some Astragalus L. (Fabaceae) species from studies reported over the past 5-7 years. The aerial and underground parts of 34 Astragalus species contain triterpene saponins, flavonoids, polysacharides, tannins, free organic acids, higher fatty acids, vitamins, trace elements, and other constituents. Among the Astragalus species, A. membranaceus (Fisch.) Bunge is the best studied in terms of component composition and biological activity. Anti-inflammatory, immunomodulatory, antioxidant, anticancer, cardioprotective, and hepathoprotective activities have been experimentally detected in total bioactive substances, fractions, and individual compounds extracted from various parts of A. membranaceus and A. membranaceus var. mongholicus in vitro and in vivo. The composition and biological effects of other Astragalus species are still poorly understood. The review summarizes the recent advances in studying new compounds extracted from Astragalus species and their biological activities.

Immunogenic cell death inducers for cancer therapy: An emerging focus on natural products

BACKGROUND

Immunogenic cell death (ICD) is a specific form of regulated cell death induced by a variety of stressors. During ICD, the dying cancer cells release damage-associated molecular patterns (DAMPs), which promote dendritic cell maturation and tumor antigen presentation, subsequently triggering a T-cell-mediated anti-tumor immune response. In recent years, a growing number of studies have demonstrated the potential of natural products to induce ICD and enhance tumor cell immunogenicity. Moreover, there is an increasing interest in identifying new ICD inducers from natural products.

PURPOSE

This study aimed to emphasize the potential of natural products and their derivatives as ICD inducers to promote research on using natural products in cancer therapy and provide ideas for future novel immunotherapies based on ICD induction.

METHOD

This review included a thorough search of the PubMed, Web of Science, Scopus, and Google Scholar databases to identify natural products with ICD-inducing capabilities. A comprehensive search for clinical trials on natural ICD inducers was also conducted using ClinicalTrials.gov, as well as the approved patents using the Espacenet and CNKI Patent Database.

RESULTS

Natural compounds that induce ICD can be categorized into several groups, such as polyphenols, flavonoids, terpenoids, and alkaloids. Natural products can induce the release of DAMPs by triggering endoplasmic reticulum stress, activation of autophagy-related pathways, and reactive oxygen species generation, etc. Ultimately, they activate anti-tumor immune response and improve the efficacy of cancer treatments.

CONCLUSION

A growing number of ICD inducers from natural products with promising anti-cancer potential have been identified. The detailed information presented in this review will contribute to the further development of natural ICD inducers and cancer treatment strategies based on ICD-induced responses.

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.

Buyang Huanwu Decoction suppresses ischemic stroke by suppressing glycolysis and cell apoptosis in rat brain microvascular endothelial cells

BACKGROUND

Buyang Huanwu Decoction (BHD) is widely used in Chinese clinical practice for the treatment and prevention of ischemic cerebral vascular diseases. This study was designed to investigate the effects of BHD on ischemic stroke (IS) and its underlying mechanism.

METHODS

The middle cerebral artery occlusion (MCAO) rat model and oxygen-glucose deprivation and reoxygenation (OGD/R) rat brain microvascular endothelial cell (RBMVEC) models were established. Brain infarction size and neurological score were calculated following MCAO surgery. Evans blue was used to measure blood brain barrier (BBB) permeability. Cell counting kit-8 (CCK-8) and TUNEL assays were performed to evaluate the cell viability and apoptosis of RBMVECs. Dual-luciferase reporter assay was used to analyze the transcriptional activities of apoptosis-related genes.

RESULTS

Results showed that higher infarction volume, neurological scores, and BBB permeability in the MCAO group rats were reduced after BHD treatment. Drug serum (DS) treatment had no impact on the normal RBMVECs' cell viability and cell apoptosis. Besides, DS treatment decreased the lactate production, glucose uptake, and extracellular acidification rate in normal and OGD/R-induced RBMVECs. DS treatment downregulated the protein levels of pan-lysine lactylation (kla), histone H3 lysine 18 lactylation (H3K18la), and the transcriptional of apoptotic protease activating factor-1 (Apaf-1) in OGD/R-treated RBMVECs. In addition, Apaf-1 overexpression decreased cell viability and increased apoptosis and glycolysis activity of OGD/R-treated RBMVECs.

CONCLUSION

In summary, BHD inhibited glycolysis and apoptosis via suppressing the pan-kla and H3K18la protein levels and the Apaf-1 transcriptional activity, thus restraining the progression of IS.

Astragalus polysaccharide: implication for intestinal barrier, anti-inflammation, and animal production

Intestine is responsible for nutrients absorption and plays a key role in defending against various dietary allergens, antigens, toxins, and pathogens. Accumulating evidence reported a critical role of intestine in maintaining animal and human health. Since the use of antibiotics as growth promoters in animal feed has been restricted in many countries, alternatives to antibiotics have been globally investigated, and polysaccharides are considered as environmentally friendly and promising alternatives to improve intestinal health, which has become a research hotspot due to its antibiotic substitution effect. Astragalus polysaccharide (APS), a biological macromolecule, is extracted from astragalus and has been reported to exhibit complex biological activities involved in intestinal barrier integrity maintenance, intestinal microbiota regulation, short-chain fatty acids (SCFAs) production, and immune response regulation, which are critical for intestine health. The biological activity of APS is related to its chemical structure. In this review, we outlined the source and structure of APS, highlighted recent findings on the regulation of APS on physical barrier, biochemical barrier, immunological barrier, and immune response as well as the latest progress of APS as an antibiotic substitute in animal production. We hope this review could provide scientific basis and new insights for the application of APS in nutrition, clinical medicine and health by understanding particular effects of APS on intestine health, anti-inflammation, and animal production.

Advances in research on the anti-tumor mechanism of Astragalus polysaccharides

The dry root of the soybean plant Astragalus membranaceus (Fisch) Bge. var. mongholicus (Bge) Hsiao or A. membranaceus (Fisch) Bge, Astragali Radix (AR) has a long medicinal history. Astragalus polysaccharide (APS), the natural macromolecule that exhibits immune regulatory, anti-inflammatory, anti-tumor, and other pharmacological activities, is an important active ingredient extracted from AR. Recently, APS has been increasingly used in cancer therapy owing to its anti-tumor ability as it prevents the progression of prostate, liver, cervical, ovarian, and non-small-cell lung cancer by suppressing tumor cell growth and invasion and enhancing apoptosis. In addition, APS enhances the sensitivity of tumors to antineoplastic agents and improves the body's immunity. This macromolecule has prospects for broad application in tumor therapy through various pathways. In this article, we present the latest progress in the research on the anti-tumor effects of APS and its underlying mechanisms, aiming to provide novel theoretical support and reference for its use in cancer therapy.

Astragali Radix: comprehensive review of its botany, phytochemistry, pharmacology and clinical application

Astragali Radix (A. Radix) is the dried root of Astragalus membranaceus var. mongholicus (Bge) Hsiao or Astragalus membranaceus (Fisch.) Bge., belonging to the family Leguminosae, which is mainly distributed in China. A. Radix has been consumed as a tonic in China for more than 2000 years because of its medicinal effects of invigorating the spleen and replenishing qi. Currently, more than 400 natural compounds have been isolated and identified from A. Radix, mainly including saponins, flavonoids, phenylpropanoids, alkaloids, and others. Modern pharmacological studies have shown that A. Radix has anti-tumor, anti-inflammatory, immunomodulatory, anti-atherosclerotic, cardioprotective, anti-hypertensive, and anti-aging effects. It has been clinically used in the treatment of tumors, cardiovascular diseases, and cerebrovascular complications associated with diabetes with few side effects and high safety. This paper reviewed the progress of research on its chemical constituents, pharmacological effects, clinical applications, developing applications, and toxicology, which provides a basis for the better development and utilization of A. Radix.

Structural elucidation of a non-starch polysaccharides from Lilii Bulbus and its protective effects against corticosterone-induced neurotoxicity in PC12 cells

Lilii Bulbus is a folk medicine for both culinary and medicinal purpose. In traditional medicine theory, Lilii Bulbus is usually used as an complementary therapy for nourishing the heart and lung, clearing heat in the treatment of mental instability and depression. In this study, NLPS-1a (Mw = 2610 Da, DP = 16), a water-soluble non-starch Lilii Bulbus polysaccharides, was isolated and purified. Structural analysis showed that NLPS-1a mainly contained Man and Glc with a molar ratio of 11.137 and 9.427. The glycosidic linkages of NLPS-1a were 1,3-Manp (59.93%), 1,2-Glcp (37.93%), T-Glcp (1.21%) and T-Manp (0.93%), indicating the highly-linear structures. In addition, NLPS-1a could significantly repair the injury of PC12 cells induced by corticosterone (CORT), reduce Lactate dehydrogenase (LDH) leakage and decrease the cell apoptosis in a dose-dependent manner. Above all, the results indicated that NLPS-1a had protective effects against CORT-induced neurotoxicity in PC12 cells, and might be a natural antidepressant, which enriched the study of the metabolic mechanism between herbal polysaccharides and antidepressant.

Structural changes of polysaccharides from Astragulus after honey processing and their bioactivities on human gut microbiota

BACKGROUND

Astragali Radix (also known as Astragulus) is a traditional medicinal and edible homologous plant for tonifying Qi. Honey-processed Astragalus is a dosage form of Astragali Radix processed with honey, which exhibited better efficacy of tonifying Qi than the raw product. Polysaccharides are their main active components.

RESULTS

APS2a and HAPS2a were initially isolated from Astragulus and honey-processed Astragulus. Both of them are highly branched acidic heteropolysaccharides containing ɑ-configuration and β-configuration glycosidic bonds. The molecular weight and the molecular dimension of HAPS2a decreased and the GalA contained in APS2a was converted to Gal in HAPS2a. The α-configuration galactose residue 1,3,4-α-Galp in the backbone of APS2a was converted to the corresponding β-configuration galactose residue 1,3,4-β-Galp in the backbone of HAPS2a and the uronic acid residue T-α-GalpA in the sidechain of APS2a was converted to the corresponding neutral residue T-α-Galp in the side chain of HAPS2a. Bioactivity results showed that HAPS2a had better probiotic effects on Bacteroides ovatus, Bacteroides thetaiotaomicron, Bifidobacterium longum and Lactobacillus rhamnosus strains than APS2a. After degradation, the molecular weights of HAPS2a and APS2a decreased with the changes in their monosaccharide composition. The contents of total short-chain fatty acids (SCFAs) and other organic acids in HAPS2a group were higher than APS2a group.

CONCLUSIONS

Two novel high-molecular-weight polysaccharides named APS2a and HAPS2a had different probiotic activities in vitro, which might be due to their structural differences before and after honey processing. Both of them might be possibly used as an immunopotentiator in healthy foods or dietary supplement. © 2023 Society of Chemical Industry.

Integration of diagnostic ions, molecular network and chemometrics to illustrate the chemical mechanism of Radix Astragali processed with honey

Radix Astragali (RA) is one of the most frequently used traditional Chinese medicine (TCM) in China, and honey-processed RA (HRA) is its common processing product. Thus far, their comprehensive chemical differences are not well understood. In this work, an integrated approach using Ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF-MS) combined with diagnostic ions, molecular network (MN) and chemometrics was established to profile their chemical characterizations and illustrate the chemical mechanism of RA processed with honey. A total of 226 compounds were tentatively identified including 50 flavonoid glycosides, 26 flavonoid aglycone, 56 saponins, 30 organic acids, 18 amino acids, 3 coumarins and 43 other compounds, of which 33 compounds were characterized according to MN. Their chemical differences were further investigated by integrating of multivariate statistical analysis, student's t-test analysis, linear regression analysis and MN. Consequently, multivariate statistical analysis showed that the raw and processed RA were different form each other. Besides, 33 different compounds were found to be significantly altered by student's t-test analysis. Apart from this, linear regression analysis indicated 42 and 120 compounds underwent the significant varieties. The potential chemical reactions induced by honey-processing, such as possible hydrolysis reactions and isomerization reactions, were speculated based on these variations coupled the areas changes of the nodes in MN. This study provided an efficient strategy to illustrate the chemical mechanism of TCM processing.

Structure-activity relationship of low molecular weight Astragalus membranaceus polysaccharides produced by Bacteroides

Astragalus membranaceus polysaccharides (APS) possess significant biological activities, such as anti-tumor, antiviral, and immunomodulatory activities. However, there is still a lack of research on the structure-activity relationship of APS. In this paper, two carbohydrate-active enzymes from Bacteroides in living organisms were used to prepare degradation products. The degradation products were divided into APS-A1, APS-G1, APS-G2, and APS-G3 according to molecular weight. Structural analysis showed that all degradation products had an α-1,4-linked glucose backbone, but APS-A1 and APS-G3 also had branched chains of α-1,6-linked galactose or arabinogalacto-oligosaccharide. In vitro, immunomodulatory activity evaluation results indicated that APS-A1 and APS-G3 had better immunomodulatory activity, while the immunomodulatory activities of APS-G1 and APS-G2 were comparatively weaker. Molecular interaction detection showed that APS-A1 and APS-G3 could bind to toll-like receptors-4 (TLR-4) with a binding constant of 4.6 × 10^-5 and 9.4 × 10^-6, respectively, while APS-G1 and APS-G2 failed to bind to TLR-4. Therefore, the branched chains of galactose or arabinogalacto-oligosaccharide played a crucial role in the immunomodulatory activity of APS.

Effects of different steaming times on the composition, structure and immune activity of Polygonatum Polysaccharide

ETHNOPHARMACOLOGICAL RELEVANCE

As a commonly used traditional Chinese herbal medicine, Polygonati Rhizoma has high medicinal value, it can enhance the immune capacity of the body, regulate the metabolism of blood glucose and lipids, treat weakness of the stomach and intestines and physical fatigue, and so on. There are three plant varieties of Polygonati Rhizoma recorded in Chinese Pharmacopoeia, including Polygonatum sibiricum Red., Polygonatum kingianum Coll. et Hemsl. and Polygonatum cyrtonema Hua, compared with the first two, Polygonatum cyrtonema Hua is less studied. Polygonatum cyrtonema Hua is one of the basal plants of the Chinese herb Polygonati Rhizoma, that strengthens the spleen, moistens the lungs, and benefits the kidneys. Polygonatum polysaccharide is the main active substance of Polygonatum cyrtonema Hua, which has various biological effects of regulating immune system, anti-inflammatory, anti-antidepressant, antioxidant and other effects.

AIM OF THE STUDY

In order to analyze the necessity and scientificity of multiple cycles of steaming during the traditional nine-steaming and nine-drying process of the concoction of Polygonatum, we investigated the changes in the composition and structure of polysaccharides, and explored its immunomodulatory activity and molecular biological mechanism.

METHODS

The structural characterization and molecular weight of polysaccharides were studied by scanning electron microscope (SEM), high-performance size exclusion chromatography-evaporative light scattering detector (HPSEC-ELSD) and Matrix.assisted laser resolutionu ionization time-of-flight mass spectrometry (MALDI-TOF-MS). The composition and proportion of monosaccharides were determined by PMP-HPLC method. A mouse immunosuppression model was established by intraperitoneal injection of cyclophosphamide to compare the immunomodulatory effects and mechanisms of different steaming times of Polygonatum, The changes of body mass and immune organ indices of mice were measured; the secretion levels of interleukin-2 (IL-2), interferon γ (IFN-γ) and the expression levels of immunoglobulin M (IgM) and immunoglobulin A (IgA) in serum were determined by enzyme-linked immunosorbent assay; and then flow cytometry was used to detect T-lymphocyte subpopulations to evaluate the differences of immunomodulatory effects of polysaccharides during the processing and preparation of Polygonatum. Finally, the Illumina MiSeq high-throughput sequencing platform was used to analyze short-chain fatty acids and to investigate the effects of different steaming times of Polygonatum polysaccharides on immune function and intestinal flora in immunosuppressed mice.

RESULTS

The structure of the Polygonatum polysaccharide with different steaming times changed significantly, the relative molecular weight of Polygonatum polysaccharide decreased significantly, and the monosaccharide composition of Polygonatum cyrtonema Hua with different steaming times was the same but the content was different. The immunomodulatory activity of the Polygonatum polysaccharide was enhanced after concoction, which significantly increased the spleen index and thymus index, and increased the expression of IL-2, IFN-γ, IgA and IgM. The CD4+/CD8+ ratio of Polygonatum polysaccharide also increased gradually with different steaming times, indicating enhanced immune function and significant immunomodulatory effect. The content of short-chain fatty acids in the feces of mice in both six steaming six sun-drying of Polygonatum polysaccharides (SYWPP) and nine steaming nine sun-drying of Polygonatum polysaccharides (NYWPP) groups increased significantly, including the content of propionic acid, isobutyric acid, valeric acid, and isovaleric acid, and also had a good effect on the regulation and improvement of microbial community abundance and diversity, SYWPP and NYWPP increased the relative abundance of Bacteroides and the ratio of Bacteroides and Firmicutes (B:F), while SYWPP significantly increased the abundance of Bacteroides, Alistipes and norank_f__Lachnospiraceae, but the effect of raw Polygonatum polysaccharides (RPP) and NYWPP was not significant than SYWPP.

CONCLUSION

Overall, both SYWPP and NYWPP could significantly enhance the immune activity of the organism, improve the imbalance of intestinal flora in immunosuppressed mice, and increase the content of intestinal short chain fatty acids (SCFAs), it is noteworthy that SYWPP has a better effect on the improvement of the immune activity of the organism. These findings can explore the stage of the concoction process of Polygonatum cyrtonema Hua to achieve the best effect, provide a reference basis for the development of quality standards, and at the same time promote the application of new therapeutic agents and health foods in raw and different steaming times of Polygonatum polysaccharide.

Biosynthesis and Pharmacological Activities of Flavonoids, Triterpene Saponins and Polysaccharides Derived from Astragalus membranaceus

Astragalus membranaceus (A. membranaceus), a well-known traditional herbal medicine, has been widely used in ailments for more than 2000 years. The main bioactive compounds including flavonoids, triterpene saponins and polysaccharides obtained from A. membranaceus have shown a wide range of biological activities and pharmacological effects. These bioactive compounds have a significant role in protecting the liver, immunomodulation, anticancer, antidiabetic, antiviral, antiinflammatory, antioxidant and anti-cardiovascular activities. The flavonoids are initially synthesized through the phenylpropanoid pathway, followed by catalysis with corresponding enzymes, while the triterpenoid saponins, especially astragalosides, are synthesized through the universal upstream pathways of mevalonate (MVA) and methylerythritol phosphate (MEP), and the downstream pathway of triterpenoid skeleton formation and modification. Moreover, the Astragalus polysaccharide (APS) possesses multiple pharmacological activities. In this review, we comprehensively discussed the biosynthesis pathway of flavonoids and triterpenoid saponins, and the structural features of polysaccharides in A. membranaceus. We further systematically summarized the pharmacological effects of bioactive ingredients in A. membranaceus, which laid the foundation for the development of clinical candidate agents. Finally, we proposed potential strategies of heterologous biosynthesis to improve the industrialized production and sustainable supply of natural products with pharmacological activities from A. membranaceus, thereby providing an important guide for their future development trend.

Research progress on the mechanisms underlying poultry immune regulation by plant polysaccharides

With the rapid development of poultry industry and the highly intensive production management, there are an increasing number of stress factors in poultry production. Excessive stress will affect their growth and development, immune function, and induce immunosuppression, susceptibility to a variety of diseases, and even death. In recent years, increasing interest has focused on natural components extracted from plants, among which plant polysaccharides have been highlighted because of their various biological activities. Plant polysaccharides are natural immunomodulators that can promote the growth of immune organs, activate immune cells and the complement system, and release cytokines. As a green feed additive, plant polysaccharides can not only relieve stress and enhance the immunity and disease resistance of poultry, but also regulate the balance of intestinal microorganisms and effectively alleviate all kinds of stress faced by poultry. This paper reviews the immunomodulatory effects and molecular mechanisms of different plant polysaccharides (Atractylodes macrocephala Koidz polysaccharide, Astragalus polysaccharides, Taishan Pinus massoniana pollen polysaccharide, and alfalfa polysaccharide) in poultry. Current research results reveal that plant polysaccharides have potential uses as therapeutic agents for poultry immune abnormalities and related diseases.

Astragalus polysaccharide: a review of its immunomodulatory effect

The Astragalus polysaccharide is an important bioactive component derived from the dry root of Astragalus membranaceus. This review aims to provide a comprehensive overview of the research progress on the immunomodulatory effect of Astragalus polysaccharide and provide valuable reference information. We review the immunomodulatory effect of Astragalus polysaccharide on central and peripheral immune organs, including bone marrow, thymus, lymph nodes, spleen, and mucosal tissues. Furthermore, the immunomodulatory effect of Astragalus polysaccharide on a variety of immune cells is summarized. Studies have shown that Astragalus polysaccharide can promote the activities of macrophages, natural killer cells, dendritic cells, T lymphocytes, B lymphocytes and microglia and induce the expression of a variety of cytokines and chemokines. The immunomodulatory effect of Astragalus polysaccharide makes it promising for the treatment of many diseases, including cancer, infection, type 1 diabetes, asthma, and autoimmune disease. Among them, the anticancer effect is the most prominent. In short, Astragalus polysaccharide is a valuable immunomodulatory medicine, but further high-quality studies are warranted to corroborate its clinical efficacy.

Extraction, structure, and activity of polysaccharide from Radix astragali

Radix astragali polysaccharide (RAP) is a water-soluble heteropolysaccharide. It is an immune promoter and regulator, and has antivirus, antitumor, anti-aging, anti-radiation, anti-stress, anti-oxidation and other activitys. The extraction, separation, purification, structure, activity and modification of RAP were summarized. Some extraction methods of RAP had been introduced, and the separation and purification methods of RAP were reviewed, and the structure and activity of RAP were highly discussed. Current derivatization of RAP was outlined. Through the above discussion that the yield of crude polysaccharides from Radix astragali by enzyme-assisted extraction was significantly higher than that by other extraction methods, but each extraction method had different extraction effects under certain conditions, and the activity efficiency of RAP was also different. Therefore, it is particularly important to optimize the extraction method with known better yield for the study of RAP. In addition, the purification and separation of RAP are the key factors affecting the yield and activity of RAP. At the same time, there are still few studies on the derivatiration of Radix astragali polysaccharide, but the researches in this area are very important. RAP also has many important pharmacological effects on human body, but its practical application needs further study. Finally, studies on the structure-activity relationship of RAP still need to be carried out by many scholars. This review would provide some help for further researches on various important applications of RAP.

Structural Characterization and Immunoenhancing Effects of a Polysaccharide from the Soft Coral Lobophytum sarcophytoides

Previous studies on the soft coral Lobophytum sarcophytoides (Lobophytum sp.) are mainly about small molecules, and there has been no systematic research on polysaccharides. In the study, a novel polysaccharide (LCPs-1-A) with immunoenhancing functions was successfully extracted and purified from the soft coral Lobophytum sp. After preliminary analysis, our data indicated that LCPs-1-A was composed of glucose and had a molecular weight of 4.90 × 10⁶ Da. Moreover, our findings showed that LCPs-1-A could promote the proliferation and phagocytosis of RAW264.7 cells, stimulate the production of NO and ROS, and increase the mRNA expression of IL-1β, IL-6, and TNF-α, which indicated that LCPs-1-A had a good immunoenhancing activity. Through further studies, we found that LCPs-1-A might play an immunoenhancing role through the TLR4/NF-κB signaling pathway. Therefore, our results demonstrated that LCPs-1-A might be a natural immunostimulant for use in medical and food industries.

Antiviral Compounds Based on Natural ASTRAGALUS POLYSACCHARIDE (APS): Researches and Foresight in the Strategies for Combating SARS-CoV-2 (COVID-19)

Today, finding natural polymers with desirable properties for use in various industries is one of the critical axes of research in the world. Polysaccharides are a group of natural polymers that have various applications in the pharmaceutical industry. The attachment of monosaccharides forms polysaccharides through glycosidic bonds that are widely found in various sources, including plants. Genus Astragalus belongs to the Fabaceae family. Plants belonging to this genus have different polysaccharides. Astragalus polysaccharides (APS) have attracted a great deal of attention among natural polymers because they are non-toxic, biodegradable, and biocompatible. Currently, APS has great drug potential for curing or treating various diseases. Due to the different biological activities of polysaccharides, including Astragalus, this study has investigated the chemical structure of APS, research report on antiviral, anti-inflammatory, and stimulation of cytokine secretion by these polysaccharides. Also, in this study, the pharmaceutical approaches of APS compounds, as a natural, new and inexpensive source, have been discussed as suitable candidates for use in pharmaceutical formulations and preparation of new drugs to control COVID-19 infection.

Comprehensive analysis of natural polysaccharides from TCMs: a generic approach based on UPLC-MS/MS

Here, we report a new application using liquid chromatography-electrospray mass spectrometry (UHPLC-ESI-MS) using aldononitrile acetate derivatives for simultaneous baseline separation and detection of eight neutral saccharides, two uronic acids, one ketose, and eight alditols within 14 min. The separation was performed on a Cortecs C₁₈ column using acetonitrile (A) and water (B) as the mobile phase with gradient elution. The target components were detected in selected ion monitoring (SIM) mode by mass spectrometry with an electrospray ionization (ESI) source operating in positive ionization mode. A comparison with traditional methods was used to determine the validity of the results. The UHPLC-ESI-MS method was used for quantitative analysis of free carbohydrates in water extracts of Crataegus pinnatifida as well as determination of Polygonatum cyrtonema and Glossy ganoderma monosaccharides in polysaccharides. The results demonstrate that this protocol is a comprehensive and effective technique for qualitative and quantitative analysis of plant polysaccharides from TCMs.

Protective Effects of Honey-Processed Astragalus on Liver Injury and Gut Microbiota in Mice Induced by Chronic Alcohol Intake

Honey-processed Astragalus (HPA) is a mixture of Astragalus and honey, which is a processed product of Chinese medicine. It has the active ingredients of Astragalus and the unique effects of honey. However, the mechanism of HPA for improving alcoholic liver disease (ALD) is not clear. The purpose of this study is to explore the ameliorating effect and mechanism of HPA (4 and 8 g/kg bw) on alcoholic liver injury. Two doses of HPA were orally administered to alcohol-treated mice for four weeks. The results showed that HPA could effectively reduce triglycerides (TG) by 59% and free fat acid (FFA) and total cholesterol (TC) in serum and hepatic were reduced by least 25.9%. HPA could cause a decrease in serum low-density lipoprotein cholesterol (LDL-C) from 0.145 mM to 0.117 mM, and the serum high-density lipoprotein cholesterol (HDL-C) was increased. After alcohol-treated mice were supplemented with HPA, antioxidant markers (superoxide dismutase (SOD), catalase (CAT), glutathione (GSH), and Glutathione peroxidase (GSH-Px)), liver function index (alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP)), proinflammatory cytokines (tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and interleukin-1β (IL-1β)), and liver tissue were all significantly improved. This is related to the fact that HPA can promote the expression of oxidative stress-related genes and inhibit the expression of inflammation-related genes. In addition, HPA could also regulate the disturbance of the intestinal microflora. In general, HPA could significantly improve the accumulation of serum and liver lipids caused by alcohol and the imbalance of intestinal flora in mice. It could also improve liver function, oxidative stress, and inflammation.

Evidence of immunogenic cancer cell death induced by honey-processed Astragalus polysaccharides in vitro and in vivo

Honey-processed Astragalus is a dosage form of Radix Astragalus mixed with honey by a traditional Chinese medicine processing method which improves immune activity. This pharmacological activity of honey-processed Astragalus polysaccharide (HP-APS) might be due to structural changes during the honey roasting process. Previously, we have prepared and characterized HP-APS and preliminarily found its anti-inflammatory effects. However, whether the pharmacodynamic activity of HP-APS induces tumor cell apoptosis and the mechanisms responsible for the immunogenic death (ICD) have not been elucidated. Here, A549, MC38 and B16 cells were used to evaluate the cells viability, apoptosis and cell cycles, respectively. Cellular immunogenic cell death-related molecules calreticulin (CRT), Heat Shock Proteins (HSP)70, major histocompatibility complex I (MHC-I), and co-stimulator molecules CD80/CD86 were determined by flow cytometry. The extracellular ATP release was also detected. B16-OVA and MC38-OVA cells were treated with HP-APS and co-cultivated with OT1 mouse of CD3+T cells for assessment of proliferation, in mice model, and the establishment of C57BL/B6 mouse model bearing B16 cells for assessment of HP-APS the regulation of immune activity in vivo. Our results showed that HP-APS has an inhibitory effect on tumor cell proliferation, which induces tumor cell apoptosis, preventing cells-transforming from G1 phase to S phase in cell cycles. Furthermore, HP-APS could effectively increase the expression of HSP70, CRT, MHC-I, CD86, CD80 and ATP release. T cell proliferation index is significantly improved. CD3 cell proliferation in OT1 mice was significantly increased from the 4th generation to the 5th generation. Moreover, the results have also shown that HP-APS could inhibit tumor growth by increasing immune cell infiltration in the tumor tissues. In the mouse melanoma model with HP-APS treatment, the tumor weight and volume were significantly reduced, and the growth of melanoma was inhibited. CD8⁺ T is significantly increased. The ratio of CD4⁺ T and CD8⁺ T cells numbers are also significantly increased in mouse spleen, but it is less than PD-1 alone treatment separately. Altogether, these findings suggest that HP-APS exerts anti-tumor effects, and that its underlying mechanisms might be associated with the expression of immunogenicity cell death related molecules and the immunomodulatory effects of immune cells.

Ethnopharmacological Survey and Comparative Study of the Healing Activity of Moroccan Thyme Honey and Its Mixture with Selected Essential Oils on Two Types of Wounds on Albino Rabbits

Wound healing consists of several continuous phases involving various cells and chemical intermediates. As a rich source of nutrition elements, honey has proved to have potential benefits in the treatment of various diseases. The present study was designed to investigate the healing effect of a honey mixture with selected essential oils on chemical and thermal wound models in rabbits. Dressing mixtures of Thymus vulgaris honey with three essential oils (Origanum vulgare, Rosmarinus officinalis, and Thymus vulgaris) were prepared and applied daily in the treatment groups. These essential oils were rich in phytochemicals and had significant antibacterial activity against four selected ATCC bacterial strains. Madecasol ointment was used as a standard control. The healing effect of the mixtures was evaluated by measuring wound surface area and comparing healing time. The results showed that the healing rate in the treatment groups was significantly higher than that of the untreated group and standard group. The best healing effect for burns was seen in the mixture of honey and Thymus vulgaris essential oil, which had wound closure rates of 85.21% and 82.14% in thermal- and chemical-induced burns, respectively, and showed the shortest healing time (14 days) in comparison to other groups. Therefore, it can be concluded that honey mixtures have significant beneficial effects on skin wound healing and, thus, they may be used as a healing agent in different types of wounds in humans after specific clinical trials.

Astragalus Polysaccharides Enhance the Immune Response to OVA Antigen in BALB/c Mice

Vaccination has been identified as one of the most effective ways to prevent the transmission of infectious diseases in humans and animals. One of the most critical steps in vaccine development is the selection of a suitable adjuvant. Although various adjuvant candidates have been evaluated in the past few decades, only a limited amount of them are nontoxic and safe for human use. Astragalus polysaccharide (APS), due to its lack of toxicity, has been used as an immunomodulator to enhance immune responses. On the other hand, the immune effects of APS on ovalbumin are yet to be examined. Thus, in this study, we analyzed APS's effects on the immune response to ovalbumin in BALB/c mice. We have also used the classic adjuvant CpG oligodeoxynucleotide as the positive control.

Structural differences of polysaccharides from Astragalus before and after honey processing and their effects on colitis mice

Honey-processed Astragalus is a dosage form of Radix Astragali processed with honey, which exhibits better efficacy of tonifying Qi than the raw product. Polysaccharides are its main water-soluble active components. This work was designed to study the structural differences of homogeneous honey-processed Astragalus polysaccharides (HAPS3a) and Astragalus polysaccharides (APS3a) and their effects on colitis mice. The results showed that HAPS3a (Mw = 2463.5 kDa) and APS3a (Mw = 3373.2 kDa) differed in molecular weight, monosaccharide compositions, glycosidic bonds and degree of branching (DB). Notably, the molar ratios of galactose and galacturonic acid in HAPS3a were 22.66% and 33.24%, while those in APS3a were 11.87% and 49.55%, respectively. The uronic acid residues 1,4-β-GalpA and 1,6-α-GlcpA of the backbone in APS3a were converted into the corresponding neutral residues in HAPS3a after honey processing. The different DB of HAPS3a (15.35%) and APS3a (25.13%) suggested that the chain conformation became smoother. The anti-inflammatory effects on colitis mice revealed that HAPS3a exhibited better effects than APS3a by protecting intestinal mucosa, regulating the expression of cytokines and influencing microbiota diversity. Taken together, the differences in anti-inflammatory activity might be related to structural differences caused by honey processing. Our findings have laid a foundation for the processing mechanism of Astragalus.

Remyelination is enhanced by Astragalus polysaccharides through inducing the differentiation of oligodendrocytes from neural stem cells in cuprizone model of demyelination

Demyelination is the hallmark of multiple sclerosis (MS). Promoting remyelination is an important strategy to treat MS. Our previous study showed that Astragalus polysaccharides (APS), the main bioactive component of Astragalus membranaceus, could prevent demyelination in experimental autoimmune encephalomyelitis mice. To investigate the effects of APS on remyelination and the underlying mechanisms, in this study we set up a cuprizone-induced demyelination model in mice and treated them with APS. It was found that APS relieved the neurobehavioral dysfunctions caused by demyelination, and efficaciously facilitated remyelination in vivo. In order to determine whether the mechanism of enhancing remyelination was associated with the differentiation of neural stem cells (NSCs), biomarkers of NSCs, astrocytes, oligodendrocytes and neurons were measured in the corpus callosum tissues of mice through Real-time PCR, Western blot and immunohistochemistry assays. Data revealed that APS suppressed the stemness of NSCs, reduced the differentiation of NSCs into astrocytes, and promoted the differentiation into oligodendrocytes and neurons. This phenomenon was confirmed in the differentiation model of C17.2 NSCs cultured in vitro. Since Sonic hedgehog signaling pathway has been proven to be crucial to the differentiation of NSCs into oligodendrocytes, we examined expression levels of the key molecules in this pathway in vivo and in vitro, and eventually found APS activated this signaling pathway. Together, our results demonstrated that APS probably activated Sonic hedgehog signaling pathway first, then induced NSCs to differentiate into oligodendrocytes and promoted remyelination, which suggested that APS might be a potential candidate in treating MS.

Recent advances in analytical techniques for the detection of adulteration and authenticity of bee products - A review

Bee products have been considered as functional foods for a long time in China because of their wide range of biological activity. China has the largest number of bee colonies and the highest production of bee products in the world. Major bee products include honey, royal jelly, propolis and bee pollen. In recent years, consumption of bee products in China has been increasing due to an increased public awareness of their nutritional and health benefits. With the development of the Chinese economy and the improvement of people's living standards, high-end and gift-oriented products have become more popular and bee products are one of the options. However, the production of bee products cannot increase rapidly in short term and this is a driver for substantial economic-motivated adulteration. This is compounded by globalisation of supply chains which has also resulted in a rise in bee products fraud. These illicit products are eroding market prices and consumer trust, causing significant damage to the beekeeping industry. In order to provide information or solutions for regulators and consumers, in this article, we review he characteristics of bee products in China and the current situation regarding adulteration and authenticity of bee products. Moreover, advances in analytical techniques for detection of adulteration and authenticity of bee products including sensory techniques, DNA methods, isotope ratio mass spectrometry, spectroscopic techniques and mass spectrometry are reviewed. Finally, the applications and limitations of analytical methods in authentication are critically assessed. Suggestions are also put forward for the future management of China's bee products industry.

Effect of Buyang Huanwu decoction for the rehabilitation of ischemic stroke patients: a meta-analysis of randomized controlled trials

Purpose

Buyang Huanwu decoction (BHD) is a widely used traditional Chinese medicine for the rehabilitation of ischemic stroke patients in China, but its clinical efficacy and safety have not been adequately assessed. In this paper, we conducted a systematic review and meta-analysis to evaluate the efficacy and safety of BHD.

Methods

We searched seven electronic databases from inception to 31 March 2019. The language was limited to Chinese and English. Randomized controlled trials evaluating the efficacy and safety of BHD for the rehabilitation of ischemic stroke patients were included in the meta-analysis. Reviewers independently performed the screening, data extraction, bias assessment, and data analysis. The treatment efficacy was pooled in a meta-analysis using RevMan 5.3 software with a random-effect model. Any disagreement was resolved by discussion among all reviewers. The PRISMA statement was used in the review process.

Results

A total of 11 studies with 1084 patients were included in the meta-analysis. The results suggested that BHD was superior to other treatments in terms of clinical efficacy in symptoms and daily activities (n = 684, RR = 1.12, 95% CI: 0.99 to 1.27), clinical efficacy in TCM symptoms (n = 280, RR = 1.45, 95% CI: 1.03 to 2.03), National Institute of Health stroke scale (n = 192, MD = 1.66, 95% CI: -1.08 to 4.40), and activities of daily living (n = 200, MD = 8.20, 95% CI: -3.95 to 20.35).

Conclusions

The results supported the clinical use of BHD for the rehabilitation of ischemic stroke patients. However, the methodological qualities of the included studies were relatively low, and there were limited reports on adverse events. The clinical efficacy and safety of BHD need to be further confirmed by more well-designed and high-quality randomized controlled trials to warrant the clinical recommendation of BHD for the rehabilitation of ischemic stroke patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12955-021-01728-6.

Structural Characterization and Immune Activity Screening of Polysaccharides With Different Molecular Weights From Astragali Radix

Saccharides are the most abundant substance with the strongest immunological activity in Astragali Radix (AR). However, systematic structure study and immunoactivity screening of polysaccharides with different molecular weights (Mw) in AR have yet to be conducted. In this study, Astragalus polysaccharides (APSs) were divided into three fragments of different Mw values, >2,000 kDa (APS-Ⅰ), about 10 kDa (APS-Ⅱ), and about 300 Da (APS-Ⅲ), by using ultrafiltration for the first time. The structural differences of the three products were determined on the basis of monosaccharide composition, FT-IR spectrum, linkage analysis, and nuclear magnetic resonance analysis. Cellular immune activity experiments in vitro and cyclophosphamide immunosuppression animal model experiments in vivo for nonspecific and specific immunoactivity screening were applied to identify the most immunogenic fragment in APSs. Linkage analysis results showed that APS-Ⅰ, APS-Ⅱ, and APS-Ⅲ have different attachment sites of monosaccharide residues. Immune screening experiments indicated that the Mw of the APSs influenced their activity, and APS-Ⅱ had the strongest immunoenhancing activity among the products. This research may serve as a reference for further study on APSs with different structures and immune activities, and as a guidance for the quality control of APSs and the development of new APS products.

Prebiotic Potential and Anti-Inflammatory Activity of Soluble Polysaccharides Obtained from Soybean Residue

In the present study, we assessed the extraction of low molecular weight soluble polysaccharides (MESP) from soybean by-products using microwave-assisted enzymatic technology and proposed the chemical structure of MESP using Fourier transform-infrared spectroscopy, gas chromatography, and ¹H and ¹³C nuclear magnetic resonance spectrum analysis. The results suggested that MESP mainly comprised arabinose, rhamnose, and glucuronic acid with (1→4) glycosidic linkages in the backbone. Compared with inulin, MESP was found to selectively stimulate the growth of Lactobacillus probiotics. Moreover, the results of in vitro fermentation indicated that MESP significantly increased the concentrations of both acetate and butyrate (p < 0.05). MESP were treated on lipopolysaccharide (LPS)-stimulated RAW264.7 cells to determine the anti-inflammatory effect in vitro. It was observed that MESP inhibited nitric oxide, tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, and IL-10 production. Furthermore, Western blotting results indicated that MESP significantly attenuated LPS-induced downregulation of phosphorylation levels of Janus kinase 2 (JAK2) and signal transducer and activator of transcription 3 (STAT3) in macrophages. The underlying mechanism might involve inhibition of the expression of pro-inflammatory cytokines, presumably via JAK2/STAT3 pathway. Collectively, the results of our study paved way for the production of MESP, which may be potentially used as nutraceutical ingredients for prebiotics and anti-inflammatory agents, from soybean residue.

Pharmacovigilance of herb-drug interactions: A pharmacokinetic study on the combination administration of herbal Kang'ai injection and chemotherapy irinotecan hydrochloride injection by LC-MS/MS

Chinese herbal drugs are often combined with chemotherapy drugs for the treatment of cancers. However, the combination administrations often do not have scientifically sound bases established on full preclinical and clinical investigations. A commonly used anti-colon-cancer herb-drug pair, irinotecan (CPT-11) hydrochloride injection and Kang'ai (KA) injection was taken as an example to investigate the possible pharmacokinetic interactions between Chinese herbal drugs and chemotherapy injections to determine the potential adverse drug reactions (ADRs). Rats were randomly divided into three groups and received 20 mg/kg CPT-11 injection 15 min after administration of 4 mL/kg saline for the CPT-11 single administration group and 4 mL/kg KA injection for the separated co-administration group, respectively. In the pre-mixed co-administration group, rats received a mixture of 20 mg/kg CPT-11 injection and 4 mL/kg KA injection. Blood samples were collected at 10 pre-determined time points between 0 and 24 h. The tissue samples were collected at 5 and 8 min after the injections, respectively. A reliable LC-MS/MS method was established for the simultaneous determination of CPT-11 and its metabolites, SN-38, SN-38 G and APC in the rat plasma and tissue samples, after full confirmation of two injections chemical and stability compatibilities. Compared to the C₀ (5129 ± 757 ng/mL) and AUC_0-t (7858 ± 1307 ng h/mL) of CPT-11 in the CPT-11 single administration group, the C₀ (4574 ± 371 ng/mL) and AUC_0-t (8779 ± 601 ng h/mL) after the separated co-administration remained unchanged, but the pre-mixed co-administration resulted with a significant increased C₀ (29,454 ± 12,080 ng/mL) and AUC_0-t (15,539 ± 5165 ng h/mL) (p < 0.05). Since the exposures of CPT-11 in most tissues in the pre-mixed co-administration group were dramatically lower than the separated co-administration group, the increased CPT-11 plasma concentration may be produced by the delayed tissue distribution because of the encapsulation by the components contained in KA injection, such as polysaccharides. Similar differences were also found in its metabolite, SN-38 G. There are obvious herb-drug interactions between CPT-11 injection and KA injection after the pre-mixed co-administration. The resulting excessive CPT-11 in the plasma may lead to many serious ADRs. Therefore, the full evaluation of herb-drug interactions is necessary and inappropriate combinations should be avoided.

Applications of nuclear magnetic resonance spectroscopy to the evaluation of complex food constituents

Due to a number of unparalleled advantages such as fastness, accuracy, intactness, nuclear magnetic resonance spectroscopy (NMR) has fulfilled a significant role in determining structures and dynamics of various physical, chemical and biological systems in the field of food analysis. This study introduced the principle of NMR, key NMR techniques such as ¹H NMR, DOSY, NOESY, HSQC, etc., and the knowledge of NMR applications on the evaluation of complex food system, especially the interactions of food components. The reviewed research work provides sufficient evidence that NMR spectroscopy has been an invaluable tool and will play an increasingly important role in specific technical support for food assessment. In addition, NMR combined with various other technologies could give a complete picture of the mechanism of the performance of functional food compounds, which are vital for human health and influence the intrinsic food properties during processing, storage and transportation at the molecular level.

A metabonomics and lipidomics based network pharmacology study of qi-tonifying effects of honey-processed Astragalus on spleen qi deficiency rats

Honey-processed Astragalus is a dosage form of radix Astragali processed with honey, which is deemed to contain better qi-tonifying effects in traditional Chinese medicine theroy. Our previous study has demonstrated that honey-processed Astragalus exhibited a better effect on reinforcing qi (vital energy) and immune improvement toward spleen qi deficiency compared with radix Astragali. However, the detailed mechanisms related to qi-tonifying effects of honey-processed Astragalus is still unclear. In this study, we evaluated the qi-tonifying effects of honey-processed Astragalus on spleen qi deficiency rats and predicted the mechanisms by aggregating metabonomics, lipidomics and network pharmacology. The results revealed that body weights, symptom scores, the levels of red blood cell, white blood cell, lymphocyte, spleen and thymus indexes, and three cytokines (TNF-α, IL-6, IFN-γ) in honey-processed Astragalus treated rats were improved in comparison with spleen qi deficiency rats. In parallel, based on the 26 biomarkers screened in metabonomics and lipidomics, we inferred that glycerophospholipid metabolism significantly regulated in pathway analysis was connected with qi-tonifying effects. Moreover, the network pharmacology analysis concluded that the compounds targets of honey-processed Astragalus CDK2, NOS3, MAPK14, PTGS1 and PTGS2 interacted with markers targets PLA2G(s) family and LYPLA1 could be responsible for regulation of glycerophospholipid metabolism to develop qi-tonifying effects. What's more, the above processes were possibly through VEGF signaling and MAPK signaling pathways.

Chemical basis of hawthorn processed with honey protecting against myocardial ischaemia

Hawthorn including many plants from the genus Crataegus (C.) is used for traditional medicines, herbal drugs, and dietary supplements all over the world. In China, C. pinnatifida Bge. var. major N, E. Br, and C. pinnatifida Bge. are two major species that are used as hawthorn. The purpose of this study is to assay the myocardial protection of hawthorn fruit processed with honey (MSZ) and screen the chemical basis of MSZ on this effect. Firstly, ultra-performance liquid chromatography-quadrupole time of flight-mass spectrometry (UPLC/Q-TOF-MS) was used to analyze the chemical constituents of the sliced dry fruit of hawthorn (SZ) and MSZ. Principal component analysis (PCA) was used to differentiate them. Orthogonal partial least squares-discriminate analysis (OPLS-DA) was applied to screen different compounds between SZ and MSZ, and 32 different compounds were selected. Then a pharmacodynamic test to investigate their protective effect against myocardial ischaemia was carried out. The results demonstrated that the protective effect of MSZ was better than that of SZ on the same dose. Finally, the chemical basis for the protective effect provided by MSZ against myocardial ischaemia was speculated based on correlation analysis. Taken together, all these results suggest that phenylpropanoids, organic acids, tannins, and flavonoids might be the chemical basis of MSZ protecting against myocardial ischaemia.

A Review of the Pharmacological Action of Astragalus Polysaccharide

Astragalus membranaceus (A. membranaceus) is a type of traditional Chinese medicine with a long history of clinical application. It is used in the improvement and treatment of various diseases as medicine and food to invigorate the spleen and replenish qi. The main components of A. membranaceus are Astragalus polysaccharide (APS), flavonoids compounds, saponins compounds, alkaloids, etc. APS is the most important natural active component in A. membranaceus, and possesses multiple pharmacological properties. At present, APS possess the huge potential to develop a drug improving or treating different diseases. In this review, we reveal the potential approaches of pre-treating and preparation on APS as much as possible and the study on content of APS and its chemical composition including different monosaccharides. More importantly, this paper summarize pharmacological actions on immune regulation, such as enhancing the immune organ index, promoting the proliferation of immune cells, stimulating the release of cytokines, and affecting the secretion of immunoglobulin and conduction of immune signals; anti-aging; anti-tumor by enhancing immunity, inducing apoptosis of tumor cells and inhibiting the proliferation and transfer of tumor cells; antiviral effects; regulation of blood glucose such as type I diabetes mellitus, type II diabetes mellitus and diabetic complications; lipid-lowering; anti-fibrosis; antimicrobial activities and anti-radiation. It provided theoretical basis for the further research such as its structure and mechanism of action, and clinical application of APS.

Astragalus Polysaccharides/Chitosan Microspheres for Nasal Delivery: Preparation, Optimization, Characterization, and Pharmacodynamics

Chitosan (CTS) constitutes a promising area in treatment of nose-related diseases as a nasal drug delivery carrier. Astragalus polysaccharide (APS) significantly attenuates eosinophils and neutrophil-dominant airway inflammation, and it has a potential pharmaceutical application in the treatment of severe asthma. The purpose of this work was to prepare APS/CTS microspheres intended for nasal drug delivery by the spray-drying method. The characteristics of APS/CTS microspheres were evaluated by a scanning electron microscope, Fourier transform infrared spectroscopy, differential scanning calorimetry, and in vitro drug release. The effect of APS/CTS microspheres on rats with allergic rhinitis (AR) was investigated by eosinophil and neutrophil counts in nasal lavage fluid. Results of SEM showed that microspheres were spherical and wrinkled. In vitro release showed that 67.48-93.76% APS was released from APS/CTS microspheres at pH 6.8 within 24 h. The effects showed that APS/CTS microspheres alleviated allergic symptoms and reduced eosinophils infiltration and the expression of interleukin-4 in the nasal mucosa tissue of rats that had no liver and kidney toxicity by hematoxylin-eosin staining observation. In conclusion, these results indicated that APS/CTS microspheres had excellent characteristics for the treatment of AR.

Structural characterization, antioxidant activity, and immunomodulatory activity of non-starch polysaccharides from Chuanminshen violaceum collected from different regions

Chuanminshen violaceum has been used as an important traditional Chinese medicine and a popular tonic food in China. Polysaccharides are considered the major bioactive components in C. violaceum. In this study, in order well understand the chemical structures and bioactivities of non-starch polysaccharides in C. violaceum (CVPs), the physicochemical structures, antioxidant activities, and immunomodulatory activities of CVPs in C. violaceum collected from different regions of China were investigated and compared. Results showed that the constituent monosaccharides and Fourier transform infrared spectra of CVPs in C. violaceum collected from different regions were similar. However, their molar ratios of constituent monosaccharides, molecular weights, and contents of uronic acids were different. Furthermore, CVPs exerted remarkable antioxidant activities (ABTS and nitric oxide radical scavenging capacities) and immunomodulatory activities (promoted production of nitric oxide, IL-6, and TNF-α from RAW 264.7 macrophages in vitro). Meanwhile, the antioxidant and immunomodulatory activities of CVPs extracted from C. violaceum also varied by cultivated regions. Moreover, results indicated that the antioxidant and immunomodulatory activities of CVPs were closely correlated to their α-1,4-d-galactosiduronic linkages. Results are helpful for better understanding of the structure-bioactivity relationships of CVPs, and beneficial for the improvement of their applications in pharmaceutical and functional food industries.

Analysis of Methanolic Extracts and Crude Polysaccharides from the Leaves of Chuanminshen violaceum and Their Antioxidant Activities

The root of Chuanminshen violaceum is used as an important edible and medicinal plant in China. However, its leaves are generally considered byproducts, and therefore do not have a use. Thus, the phenolic compounds in the methanolic extracts (CVLMs) and the chemical characteristics of crude polysaccharides (CVLPs) from the leaves of C. violaceum and their in vitro antioxidant activities were explored. The results showed that chlorogenic acid and rutin were the major individual phenolic compounds in the leaves, which ranged from 1.22 ± 0.03 to 2.87 ± 0.04 mg/g DW, and from 2.25 ± 0.04 to 4.03 ± 0.05 mg/g DW, respectively. Meanwhile, the extraction yields of CVLPs from the leaves ranged from 4.73% to 5.41%. The CVLPs consisted of mannose, rhamnose, galacturonic acid, glucose, galactose, and arabinose, suggesting the existence of pectic polysaccharides. Furthermore, both CVLMs and CVLPs exhibited strong antioxidant activities. Chlorogenic acid and rutin were major contributors to the antioxidant activities of CVLMs, and the antioxidant activities of CVLPs were closely correlated to their α-1,4-D-galactosiduronic linkages. The results are beneficial for understanding the chemical properties and in vitro antioxidant activities of CVLMs and CVLPs. The leaves of C. violaceum have potential to be developed as natural antioxidants.

Astragalus polysaccharides attenuated inflammation and balanced the gut microflora in mice challenged with Salmonella typhimurium

Salmonella typhimurium (S. t.) is one of the main pathogens that causes acute gastroenteritis. To evaluate the anti-inflammatory mechanism of Astragalus polysaccharide (APS) in vivo and its influence on the intestinal flora, BALB/c mice were infected with S. t. to establish a model of diarrhea. The disease activity index (DAI) scores showed that APS attenuated S. t.-induced weight loss and diarrhea in mice. APS significantly reduced the index of the liver and spleen as well as the ALT and AST levels in serum (P < 0.05). Hematoxylin and eosin (H&E) results indicated that APS significantly increased jejunum villus height and crypt depth and reduced the infiltration of inflammatory cells (P < 0.05). Additionally, APS increased the tight junction (TJ) proteins expression levels of ZO-1, Occludin and Claudin-1 in the jejunum. The results of 16S rDNA showed that APS significantly increased the number of Lactobacillus and Bifidobacterium spp. to normal levels (compared with the control group). In addition, APS significantly decreased the mRNA expression levels of the proinflammatory cytokines TNF-α, IL-1β, IL-6 and IL-17 in the jejunum (P < 0.01) as well as the proteins expression levels of COX-2 and iNOS (P < 0.05). Western blot confirmed that prefeeding with APS inhibited S. t.-induced expression of TLR4 and MyD88 in the jejunum and further inhibited nuclear factor-κB (NF-κB) activation, including the nuclear translocation of the p65 NF-κB subunit and the phosphorylation and degradation of IκB-α. This was the key to APS inhibition of the production of inflammatory factors and inflammatory mediators in the jejunum.

Extraction, Structure, and Pharmacological Activities of Astragalus Polysaccharides

The Astragalus polysaccharides (APS) are important bioactive components of Astragali Radix, the dry root of Astragalus membranaceus, which has been used in traditional Chinese medicine. In this review, the extraction conditions and extraction rates of APS are first compared for water, microwave-assisted, ultrasonic wave, and enzymatic hydrolysis extraction methods. Some studies have also shown that different methods can be combined to improve the extraction rate of APS. Subsequently, the chemical composition and structure of APS are discussed, as related to the extraction and purification method. Most studies have shown that APS is mainly composed of glucose, in addition to rhamnose, galactose, arabinose, xylose, mannose, glucuronic acid, and galacturonic acid. We also reviewed studies on the modification of APS using chemical methods, including sulfated modification using the chlorosulfonic acid–pyridine method, which is commonly used for chemical modification of APS. Finally, the pharmacological activities and mechanisms of action of APS are summarized, with a special focus on its immunoregulatory, antitumor, anti-inflammatory, and antiviral effects. This review will serve as a valuable resource for the research on APS.