Vaccination with Astragalus and Ginseng Polysaccharides Improves Immune Response of Chickens against H5N1 Avian Influenza Virus

Astragalus Polysaccharide improves immunogenicity of influenza vaccine as well as modulate gut microbiota in BALB/c mice

BACKGROUND

Vaccination is the best way to prevent influenza virus infection, and insufficient antibodies make it difficult to resist influenza virus invasion. Astragalus Polysaccharide (APS) has a boosting effect on immunity, so we evaluate the effect of APS as an immune adjuvant for H1N1 influenza vaccines in this study.

METHODS

The mice were immunized twice with influenza A (H1N1) vaccine and APS. Subsequently, the serum antibody levels were assessed using enzyme-linked immunosorbent assay (ELISA). The frequency of peripheral immune T cells was determined by flow cytometry. Following this, the immunized mice were exposed to a lethal dose of the virus, and changes in body weight and survival rates were recorded. Hematoxylin-eosin staining was employed to observe pathological alterations in lung and intestinal tissues. Western blot analysis was conducted to detect the expression of intestinal barrier function proteins (Occludin and Claudin-1). ELISA was utilized to measure the expression level of serum inflammatory cytokine TNF-α. Fresh mouse feces were collected after the initial immunization as well as after viral infection for 16S rRNA analysis aimed at detecting alterations in gut microbiota.

RESULTS

Compared to the Hemagglutinin (HA) group, the APS group demonstrated higher levels of immunoglobulin G (IgG), IgG1, and IgG3, as well as neutralizing antibody levels. Additionally, it increased the frequency of CD8+ cells to enhance resistance against lethal infection. On day 14 post-infection, the high-dose APS group exhibited a higher survival rate (71.40 %) compared to the HA group (14.28 %), along with faster weight recovery. Furthermore, APS was found to ameliorate alveolar damage in lung tissue and rectify intestinal structural disorder. It also upregulated the expression levels of tight junction proteins Occludin and Claudin-1 in intestinal tissue while reducing serum TNF-α expression levels. In addition, populations of Colidextribacter, Peptococcaceae, and Ruminococcaceae were the dominant gut microbiota in the APS group after viral infection.

CONCLUSION

APS has an immune-enhancing effect and is expected to be a novel adjuvant in the H1N1 influenza vaccine.

Isolation, structure, biological activity and application progress of ginseng polysaccharides from the Araliaceae family

Phytopolysaccharides are a class of natural macromolecules with a range of biological activities. Ginseng, red ginseng, American ginseng, and Panax notoginseng are all members of the Araliaceae family. They are known to contain a variety of medicinal properties and are typically rich in a wide range of medicinal values. Polysaccharides represent is one of the principal active ingredients in the aforementioned plants. However, there is a paucity of detailed reports on the separation methods, structural characteristics and comparison of various pharmacological effects of these polysaccharides. This paper presents a review of the latest research reports on ginseng, red ginseng, American ginseng and ginseng polysaccharides. The differences in extraction, separation, purification, structural characterization, and pharmacological activities of the four polysaccharides are compared and clarified. Upon examination of the current research literature, it becomes evident that the extraction and separation processes of the four polysaccharides are highly similar. Modern pharmacological studies have corroborated the multiple biological activities of these polysaccharides. These activities encompass a range of beneficial effects, including antioxidant stress injury, fatigue reduction, tumor inhibition, depression alleviation, regulation of intestinal flora, immunomodulation, diabetes management, central nervous system protection, anti-aging, and improvement of skin health. This paper presents a review of studies on the extraction, purification, characterization, and bioactivities of four natural plant ginseng polysaccharides. Furthermore, the review presents the most recent research findings on their pharmacological activities. The information provides a theoretical basis for the future application of natural plant polysaccharides and offers a new perspective for the in-depth development of the medicinal value of ginseng in the clinical practice of traditional Chinese medicine.

Structural analysis of a soluble polysaccharide GSPA-0.3 from the root of Panax ginseng C. A. Meyer and its adjuvant activity with mechanism investigation

A novel polysaccharide (GSPA-0.3) was isolated and purified from the root of cultivated Panax ginseng C. A. Meyer, and its structure, adjuvant activities, and mechanisms for inducing the maturation of mouse dendritic 2.4 cells (DC2.4) were extensively studied. Fraction GSPA-0.3, mainly composed by the galacturonic acid, galactose, arabinose, glucose, rhamnose, mannose, and xylose, had a molecular weight of 62,722 Da. The main chain of GSPA-0.3 was composed of →3)-α-L-Rhap-(1→, →4)-α-D-GalpA-(1→, and →3, 4)-α-D-GalpA-(1→. Branched chains comprised α-L-Araf-(1→3, 5)-α-L-Araf-(1→5)-α-L-Araf-(1→, α-D-Glcp-(1→6)-α-D-Glcp-(1→6)-α-D-Glcp-(1→, β-D-Galp-(1→4)-β-D-Galp-(1→4)-β-D-Galp-(1→, and α-D-GalpA-(1→ units connected to the C3 position of →3, 4)-α-D-GalpA-(1→. In vivo, GSPA-0.3 was found to stimulate the production of IgG, IgG1, and IgG2a; increase the splenocyte proliferation index; and promote the expression of GATA-3, T-bet, IFN-γ, and IL-4 in H1N1 vaccine-immunized mice. Moreover, GSPA-0.3 significantly increased the levels of neutralizing antibodies in the mice, and its adjuvant activity was found to be superior to aluminum adjuvant (Alum adjuvant). Mechanistic investigations showed that GSPA-0.3 activated the TLR4-dependent pathway by upregulating the expressions of TLR4, MyD88, TRAF-6, and NF-κB proteins and gens. The results presented herein suggested that GSPA-0.3 could significantly promote the efficacy of the H1N1 vaccine by modulating Th1/Th2 response via the TLR4-MyD88-NF-κB signaling pathway.

Synergism of fermented feed and ginseng polysaccharide on growth performance, intestinal development, and immunity of Xuefeng black-bone chickens

Microbial fermented feed (MF) is considered a valuable strategy to bring advantages to livestock and is widely practiced. Oral supplementation of Ginseng polysaccharide (Gps) eliminated weight loss in chickens following vaccination. This study investigated the effects of the combined use of Gps and MF on growth performance and immune indices in Xuefeng black-bone chickens. A total of 400 Xuefeng black-bone chickens at the age of 1 day were randomly assigned to four groups. Normal feed group (Control group), ginseng polysaccharide (200 mg/kg) group (Gps group), microbially fermented feed (completely replace the normal feed) group (MF group), and microbially fermented feed and add ginseng polysaccharide just before use (MF + Gps group). Each group contained 5 pens per treatment and 20 birds per pen. The body weight and average daily gain in the Gps, MF, and MF + Gps groups increased significantly (P < 0.01), while the feed conversion ratio decreased significantly (P < 0.01). The combined use of MF and Gps showed a synergistic effect. There was no significant difference in villus height (cecal) between the experimental group and the Con group. The crypt depth of the three experimental groups exhibited a significantly lower value compared to the Control group (P < 0.05). The V/C ratio of the Gps group and MF + Gps was significantly increased (P < 0.05), but there was no significant difference in the MF group. Moreover, the diarrhea rate of the Gps and the MF + Gps groups was lower than that of the Con group, while that of the MF + Gps group decreased the mortality rate (P < 0.05). The serum tumor necrosis factor-alpha (TNF-α) and interleukin 6 (IL-6) levels in the MF, Gps, and MF + Gps groups decreased significantly (P < 0.01), the serum immunoglobulin G (IgG) levels increased significantly (P < 0.01), while the combination of MF and Gps had a synergistic effect. The combined use of Gps and MF not only further improved growth performance and immune parameters, but also reduced the diarrhea rate and mortality.

Antiviral activities of ginseng and its potential and putative benefits against monkeypox virus: A mini review

Due to the Covid-19 pandemic more than 6 million people have died, and it has bought unprecedented challenges to our lives. The recent outbreak of monkeypox virus (MPXV) has brought out new tensions among the scientific community. Currently, there is no specific treatment protocol for MPXV. Several antivirals, vaccinia immune globulin (VIG) and smallpox vaccines have been used to treat MPXV. Ginseng, one of the more famous among traditional medicines, has been used for infectious disease for thousands of years. It has shown promising antiviral effects. Ginseng could be used as a potential adaptogenic agent to help prevent infection by MPXV along with other drugs and vaccines. In this mini review, we explore the possible use of ginseng in MPXV prevention based on its antiviral activity.

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.

Effects of dietary Glycyrrhiza polysaccharide on growth performance, blood parameters and immunity in weaned piglets

The purpose of this study was to evaluate the effects of dietary Glycyrrhiza polysaccharide (GCP) on growth performance, blood parameters and immunity in weaned piglets. A total of 240 (10.33 ± 0.62 kg body weight) 35-day-old (Duroc × Landrace × White) weaned piglets were randomly assigned to four dietary treatments, with six replicate pens per treatment and 10 piglets per pen (five males and five females). The dietary treatments continued for 21 days and comprised a basal diet supplemented with 0 (control group), 500, 1000 and 2000 mg/kg GCP. The results showed that the inclusion of 1000 and 2000 mg/kg GCP increased the average daily gain and decreased the feed conversion rate compared with the control group (p < 0.05). The piglets treated with 500 and 1000 mg/kg GCP had a lower diarrhoeal incidence than the control group (p < 0.05). Moreover, supplementation with 1000 mg/kg GCP increased the counts of white blood cells, neutrophils, red blood cells, and platelets, and elevated alkaline phosphatase, total protein, globulin, glucose, triglyceride, immunoglobulin A, immunoglobulin G, and total antioxidant capacity levels (p < 0.05), and decreased malondialdehyde content compare with the control group (p < 0.05). In addition, relative to the control group, piglets fed 500 and 1000 mg/kg GCP had significantly lower expression of interleukin-6 mRNA in spleen (p < 0.05). Our results indicate that dietary supplementation with GCP can improve growth performance, blood parameters and immunity in weaned piglets. Our study suggests that adding 1000 mg/kg GCP to the diet had the most beneficial effect.

Advances in Research on Antiviral Activities of Sulfated Polysaccharides from Seaweeds

In recent years, various viral diseases have suddenly erupted, resulting in widespread infection and death. A variety of biological activities from marine natural products have gradually attracted the attention of people. Seaweeds have a wide range of sources, huge output, and high economic benefits. This is very promising in the pharmaceutical industry. In particular, sulfated polysaccharides derived from seaweeds, considered a potential source of bioactive compounds for drug development, have shown antiviral activity against a broad spectrum of viruses, mainly including common DNA viruses and RNA viruses. In addition, sulfated polysaccharides can also improve the body’s immunity. This review focuses on recent advances in antiviral research on the sulfated polysaccharides from seaweeds, including carrageenan, galactan, fucoidan, alginate, ulvan, p-KG03, naviculan, and calcium spirulan. We hope that this review will provide new ideas for the development of COVID-19 therapeutics and vaccines.

Advances in the Prophylaxis of Respiratory Infections by the Nasal and the Oromucosal Route: Relevance to the Fight with the SARS-CoV-2 Pandemic

In this time of COVID-19 pandemic, the strategies for prevention of the infection are a primary concern. Looking more globally on the subject and acknowledging the high degree of misuse of protective face masks from the population, we focused this review on alternative pharmaceutical developments eligible for self-defense against respiratory infections. In particular, the attention herein is directed to the nasal and oromucosal formulations intended to boost the local immunity, neutralize or mechanically "trap" the pathogens at the site of entry (nose or mouth). The current work presents a critical review of the contemporary methods of immune- and chemoprophylaxis and their suitability and applicability in topical mucosal dosage forms for SARS-CoV-2 prophylaxis.

Multi-level fingerprinting and cardiomyocyte protection evaluation for comparing polysaccharides from six Panax herbal medicines

The role of polysaccharides in quality control of ginseng is underestimated. Large-scale comparison on the polysaccharides of Panax ginseng (PG), P. quinquefolius (PQ), P. notoginseng (PN), Red ginseng (RG), P. japonicus (ZJS), and P. japonicus var. major (ZZS), was performed by both chemical and biological approaches. Holistic fingerprinting at polysaccharide and the hydrolyzed oligosaccharide and monosaccharide levels utilized various chromatography methods, while OGD and OGD/R models on H9c2 cells were introduced to evaluate the protective effects on cell viability and mitochondrial function. Polysaccharides from six ginseng species exhibited remarkable content difference (RG > PG/ZZS/ZJS/PQ > PN), but weak differentiations in molecular weight distribution and oligosaccharide profiles, while Glc and GalA were richer for monosaccharide compositions of PG and RG polysaccharides, respectively. RG polysaccharides (25/50/100 μg/mL) showed significant cardiomyocyte protection by regulating mitochondrial functions. These new evidences may provide support for the supplementary role of polysaccharides in quality control of ginseng.

Polysaccharides derived from Chinese medicinal herbs: A promising choice of vaccine adjuvants

Adjuvants have been used in vaccines for a long time to promote the body's immune response, reducing vaccine dosage and production costs. Although many vaccine adjuvants are developed, the use in human vaccines is limited because of either limited action or side effects. Therefore, the development of new vaccine adjuvants is required. Many studies have found that natural polysaccharides derived from Traditional Chinese medicine (TCM) possess good immune promoting effects and simultaneously improve humoral, cellular and mucosal immunity. Recently polysaccharide adjuvants have attracted much attention in vaccine preparation because of their intrinsic characteristics: immunomodulation, biocompatibility, biodegradability, low toxicity and safety. This review article systematically analysed the literature on polysaccharides possessing vaccine adjuvant activity from TCM plants, such as Astragalus polysaccharide (APS), Rehmannia glutinosa polysaccharide (RGP), Isatis indigotica root polysaccharides (IRPS), etc. and their derivatives. We believe that polysaccharide adjuvants can be used to prepare the vaccines for clinical use provided their mechanisms of action are studied in detail.

Review of herbal medicine works in the avian species

Poultry meat consumption is increasing worldwide but the overuse of antimicrobials for prevention and treatment of diseases has increased antimicrobial resistance (AMR), triggering a major public health issue. To restrict AMR emergence, the government supports the optimization of natural products that are safe and easy to obtain with minimal side effects on poultry, humans, and the environment. Various studies have explored the potential of herbs in animal health for their antiviral, antibacterial, antifungal, antiparasitic, immunomodulatory, antioxidant, and body weight gain properties. Therefore, this study reviewed plants with potential application in avian species by summarizing and discussing the mechanisms and prophylactic/therapeutic potential of these compounds and their plant origin extracts.

Immunostimulant Bathing Influences the Expression of Immune- and Metabolic-Related Genes in Atlantic Salmon Alevins

Disease resistance of fish larvae may be improved by bath treatment in water containing immunostimulants. Pattern recognition receptors, such as TLR3, TLR7, and MDA5, work as an "early warning" to induce intracellular signaling and facilitate an antiviral response. A single bath of newly hatched larvae, with Astragalus, upregulated the expression of IFNα, IFNc, ISG15, MDA5, PKR, STAT1, TLR3, and TLR7 immune genes, on day 4 post treatment. Similar patterns were observed for Hyaluronic acid and Poly I:C. Increased expression was observed for ISG15, MDA5, MX, STAT1, TLR3, TLR7, and RSAD2, on day 9 for Imiquimod. Metabolic gene expression was stimulated on day 1 after immunostimulant bath in ULK1, MYC, SLC2A1, HIF1A, MTOR, and SIX1, in Astragalus, Hyaluronic acid, and Imiquimod. Expression of NOS2 in Poly I:C was an average fourfold above that of control at the same timepoint. Throughout the remaining sampling days (2, 4, 9, 16, 32, and 45 days post immunostimulant bath), NOS2 and IL1B were consistently overexpressed. In conclusion, the immunostimulants induced antiviral gene responses, indicating that a single bath at an early life stage could enable a more robust antiviral defense in fish. Additionally, it was demonstrated, based on gene expression data, that cell metabolism was perturbed, where several metabolic genes were co-regulated with innate antiviral genes.

Marine sulfated polysaccharides as potential antiviral drug candidates to treat Corona Virus disease (COVID-19)

The viral infection caused by SARS-CoV-2 has increased the mortality rate and engaged several adverse effects on the affected individuals. Currently available antiviral drugs have found to be unsuccessful in the treatment of COVID-19 patients. The demand for efficient antiviral drugs has created a huge burden on physicians and health workers. Plasma therapy seems to be less accomplishable due to insufficient donors to donate plasma and low recovery rate from viral infection. Repurposing of antivirals has been evolved as a suitable strategy in the current treatment and preventive measures. The concept of drug repurposing represents new experimental approaches for effective therapeutic benefits. Besides, SARS-CoV-2 exhibits several complications such as lung damage, blood clot formation, respiratory illness and organ failures in most of the patients. Based on the accumulation of data, sulfated marine polysaccharides have exerted successful inhibition of virus entry, attachment and replication with known or unknown possible mechanisms against deadly animal and human viruses so far. Since the virus entry into the host cells is the key process, the prevention of such entry mechanism makes any antiviral strategy effective. Enveloped viruses are more sensitive to polyanions than non-enveloped viruses. Besides, the viral infection caused by RNA virus types embarks severe oxidative stress in the human body that leads to malfunction of tissues and organs. In this context, polysaccharides play a very significant role in providing shielding effect against the virus due to their polyanionic rich features and a molecular weight that hinders their reactive surface glycoproteins. Significantly the functional groups especially sulfate, sulfate pattern and addition, uronic acids, monosaccharides, glycosidic linkage and high molecular weight have greater influence in the antiviral activity. Moreover, they are very good antioxidants that can reduce the free radical generation and provokes intracellular antioxidant enzymes. Additionally, polysaccharides enable a host-virus immune response, activate phagocytosis and stimulate interferon systems. Therefore, polysaccharides can be used as candidate drugs, adjuvants in vaccines or combination with other antivirals, antioxidants and immune-activating nutritional supplements and antiviral materials in healthcare products to prevent SARS-CoV-2 infection.

Effects of astragalus polysaccharide on intestinal inflammatory damage in goslings infected with gosling plague

1. This study explored the effects of Astragalus membranaceus polysaccharide (APS) on intestinal inflammatory damage of goslings infected with parvovirus ('gosling plague').2. A total of 90 healthy goslings were randomly divided into three groups; control, infected or APS treated, respectively. Goslings in the infection and APS treatment groups were inoculated with 0.3 ml allantoic fluid containing goose parvovirus (ELD₅₀ = 1 × 10³/0.3 ml) by intramuscular injection and the control group were injected with saline (0.3 ml) twice a day for 15 days.3. Blood serum and the jejunum were collected at 5, 10 and 15 days after the start of the experiment to detect the activities of SOD and GSH-Px, levels of MDA, sIgA, IL-1β, IL-6 and TNF-α, the mRNA expression of IL-1β, IL-6, LITAF, NF-κB, COX-2 and PGE2, pathological damage in the jejunum and serum IgG, IgM, C3, C4, IFN-γ levels.4. After APS treatment, SOD and GSH-Px activities increased, MDA content decreased; sIgA, IL-1β, IL-6 and TNF-α protein content, and IL-1β, IL-6, LITAF, NF-κB, COX-2 and PGE2 mRNA expression decreased in the jejunal tissue, serum IgG, IgM, C3, C4, IFN-γ significantly increased and pathological damage of jejunum significantly improved.5. In conclusion, APS reduced intestinal inflammatory damage in goslings infected with parvovirus by improving the immune and antioxidant functions of goslings.

Effects of Astragalus polysaccharides on intestinal morphology and intestinal immune cells of Muscovy ducklings infected with Muscovy duck reovirus

Muscovy duck reovirus (MDRV) infection induces serious immunosuppression and intestinal injury in Muscovy ducklings with a high morbidity and mortality, and Astragalus polysaccharide (APS) pretreatment could efficiently protect ducklings from MDRV infection, although the underlying immunoregulatory mechanisms remain unclear. Thus, the objective of this study was to investigate effects of APS on the intestinal mucosal immunity in MDRV-infected Muscovy ducklings. A total of 190 1-day-old healthy Muscovy ducklings were randomly assigned to 3 groups (n = 50): normal control group, APS pretreatment for MDRV-infected group, and cohabitation infection group, then pretreated with 0.6 g/L APS or only drinking water followed by MDRV cohabitation infection with the remaining 40 artificially infected ducklings, respectively. At the 2, 3, 4, 6, 9 and 15 d after cohabitation infection, the intestinal samples were prepared to measure intestinal parameters including villus length, villus length/crypt depth (V/C) ratio, and wall thickness, together with counts of intraepithelial lymphocyte (IEL) and goblet cell (GC) by hematoxylin-eosin staining. Meanwhile, ileal secretory IgA (sIgA) and duodenal cytokine levels of IL-4, IL-6, IL-15, tumor necrosis factor-alpha, and interferon gamma were detected by the ELISA and radioimmunoassay, respectively. The results showed that APS significantly improved intestinal injuries of villi length, V/C ratio, and wall thickness of the small intestine infected with MDRV, effectively inhibited the reduction of IEL and GC caused by MDRV infection, subsequently increased sIgA and all the cytokine secretions at most time points, suggesting that APS pretreatment can effectively stimulate mucosal immune function by improving intestinal morphology and repair MDRV caused injures of small intestinal mucosal immune barrier in infected ducklings. Our findings lay the foundation for further application of APS in prevention and treatment of MDRV infection.

Recent progress in polysaccharides from Panax ginseng C. A. Meyer

Panax ginseng C. A. Meyer (P. ginseng) has a long history of medicinal use and can treat a variety of diseases. P. ginseng contains a variety of active ingredients, such as saponins, polypeptides, volatile oils, and polysaccharides. Among them, saponins have always been considered as the main components responsible for its pharmacological activities. However, more and more studies have shown that polysaccharides play an indispensable role in the medicinal value of ginseng. Modern biological and medical studies have found that ginseng polysaccharides have complex structural characteristics and diverse biological activities, such as immune regulation, anti-tumor, antioxidant, hypoglycemic, and anti-radiation functions, among others. Additionally, the structural characteristics of ginseng polysaccharides are closely related to their activity. In this review, the research background, extraction, purification, structural characteristics, and biological activities of ginseng polysaccharides from different parts of P. ginseng (roots, flowers stems and leaves, and berries) under different growth conditions (artificially cultivated ginseng, mountain ginseng, and wild ginseng) are summarized. The structural characteristics of purified polysaccharides were reviewed. Meanwhile, their biological activities were introduced, and some possible mechanisms were listed. Furthermore, the structure-activity relationship of polysaccharides was discussed. Some research perspectives for the study of ginseng polysaccharides were also provided.

Effects of Glycyrrhiza polysaccharide in diet on growth performance, serum antioxidant capacity, and biochemistry of broilers

In the present study, we analyzed the effects of Glycyrrhiza polysaccharide (GCP) on growth performance, serum antioxidant capacity, and biochemistry of broilers. A total of 600, one-day-old AA broilers randomly divided into 5 treatment groups with 6 replicate pens of 20 birds per cage received dietary supplementation with GCP (0, 200, 500, 1,000, and 1,500 mg/kg) for 42 d. The supplementation of GCP linearly decreased (P < 0.05) feed conversion rate on day 22 to 42. Dietary supplementation with GCP reduced (P < 0.05) serum total cholesterol on day 21 and 42 and linearly improved (P < 0.05) albumin and high-density lipoprotein cholesterol. Dietary supplementation with 1,000 or 1,500 mg/kg GCP significantly increased (P < 0.05) serum total superoxide dismutase (T-SOD) activity on day 21 and 42 and reduced (P < 0.05) serum malondialdehyde content on 21 d. Dietary supplementation with 1,000 or 1,500 mg/kg GCP significantly improved (P < 0.05) interleukin-1β (IL-1β) and interferon-γ (IFN-γ) expressions in liver on day 21 and 42. At the end of the experiment, we randomly selected 20 broilers from 3 treatment groups (0, 1,000, and 1,500 mg/kg), respectively, to perform an lipopolysaccharide (LPS)-induced acute stress experiment. The 60 broilers were divided into 6 treatment groups with 10 birds per cage. The experiment was designed as a 3 × 2 factorial arrangement with GCP (0, 1,000, or 1,500 mg/kg) and LPS (injection of saline or 1 mg/kg body weight) levels as treatments. When the grouping was finished, the broilers were immediately intraperitoneally injected with LPS or normal saline. Six hours after challenged, serum antioxidant and liver immunity were analyzed. The results showed that dietary GCP prevented LPS-induced reductions in T-SOD activity and increases in malonaldehyde content (P < 0.05). Also, dietary GCP supplementation mitigated the LPS-induced increase in IL-1β and IFN-γ in the liver. Supplementation with 1,500 mg/kg GCP showed the most optimal effect in broilers. GCP has the potential to be used as feed additive in broilers.

Application prospect of polysaccharides in the development of anti-novel coronavirus drugs and vaccines

Since the outbreak of the novel coronavirus disease COVID-19, caused by the SARS-CoV-2 virus, it has spread rapidly worldwide and poses a great threat to public health. This is the third serious coronavirus outbreak in <20 years, following SARS in 2002-2003 and MERS in 2012. So far, there are almost no specific clinically effective drugs and vaccines available for COVID-19. Polysaccharides with good safety, immune regulation and antiviral activity have broad application prospects in anti-virus, especially in anti-coronavirus applications. Here, we reviewed the antiviral mechanisms of some polysaccharides, such as glycosaminoglycans, marine polysaccharides, traditional Chinese medicine polysaccharides, and their application progress in anti-coronavirus. In particular, the application prospects of polysaccharide-based vaccine adjuvants, nanomaterials and drug delivery systems in the fight against novel coronavirus were also analyzed and summarized. Additionally, we speculate the possible mechanisms of polysaccharides anti-SARS-CoV-2, and propose the strategy of loading S or N protein from coronavirus onto polysaccharide capped gold nanoparticles vaccine for COVID-19 treatment. This review may provide a new approach for the development of COVID-19 therapeutic agents and vaccines.

Astragalus polysaccharide strengthens the inflammatory and immune responses of Brucella suis S2-infected mice and macrophages

Brucella infection is one of the most serious zoonoses worldwide, affecting humans and domestic and wild animals. Astragalus polysaccharide (APS) is extracted from astragalus, which exhibits bioactive properties, including immunomodulation and anti-tumour and antiviral activity. The present study revealed that APS treatment promoted macrophage activation, the production of pro-inflammatory cytokines, including tumor necrosis factor-α (TNF-α), interleukin-12 and interferon-γ, and Brucella clearance in murine macrophages and spleens. APS treatment was also demonstrated to protect the integrity of macrophages during infection with live attenuated Brucella suis strain 2 (B. suis S2). The results from in vitro experiments were consistent with the findings from the in vivo study, showing the elevated secretion of TNF-α and nitric oxide in APS-treated murine peritoneal macrophages following B. suis S2 infection. The current study demonstrated the potential of APS in the control and treatment of Brucella infection, and the enhancement of host inflammatory and immune responses.

Effects of astragalus and ginseng polysaccharides on growth performance, immune function and intestinal barrier in weaned piglets challenged with lipopolysaccharide

This experiment was conducted to evaluate the effects of astragalus polysaccharides (Aps) and ginseng polysaccharide (Gps) on growth performance, liver function, immune function, TLR4 signalling pathways and intestinal barrier in weaned piglets challenged with lipopolysaccharide (LPS). In an experiment spanning 28 days, 180 weaned piglets were randomly divided into three treatment groups: basal diet (Con), basal diet supplemented with 800 mg/kg Gps (Gps) and basal diet supplemented with 800 mg/kg Aps (Aps). At the end of the experiment, 12 piglets of each group were selected; half (n = 6) were intraperitoneally injected with LPS and half with normal saline. Dietary supplementation with Aps and Gps significantly increased (p < .05) the average daily gain and feed conversion rate. Lipopolysaccharide challenge increased (p < .05) expression of serum urea nitrogen (BUN), alanine aminotransferase (ALT), aspartate aminotransferase (AST), interleukin-1β (IL-1β) and tumour inflammatory factor-α (TNF-α), but decreased (p < .05) serum superoxide dismutase (SOD) level, total antioxidant capacity (T-AOC) and immunoglobulin A (IgA) expression. Lipopolysaccharide-challenged piglets fed with Aps or Gps had lower (p < .05) BUN, ALT, AST, IL-1β and TNF-α levels and greater (p < .05) SOD, T-AOC and IgA levels. Lipopolysaccharide challenge increased (p < .05) the expression of TLR4, MyD88 and NF-κB, and LPS-challenged piglets fed diets supplemented with Aps or Gps increased TLR4 and MyD88 and decreased NF-κB expression. Lipopolysaccharide challenge reduced (p < .05) the jejunal villus height, and piglets fed with Aps or Gps had increased (p < .05) jejunal villus height. Supplementation with Aps or Gps enhanced the expression of occludin and claudin in challenged or unchallenged piglets. In conclusion, dietary supplementation with Aps or Gps enhanced piglet growth performance, alleviated liver dysfunction and reduced immunological stress caused by LPS, as well as increased the intestinal barrier function.

Herbal Medicine Additives as Powerful Agents to Control and Prevent Avian Influenza Virus in Poultry – A Review

The complicated epidemiological situation of avian influenza viruses (AIV) caused by continuous emergence of new subtypes with failure of eradication, monitoring and vaccination strategies opens the door to alternative solutions to save the status quo and prevent new disasters for the poultry industry. Using of synthetic antiviral drugs such as neuraminidase and hemagglutinin inhibitors has been limited due to development of drug resistance and expensive commercial application. One of the most promising alternatives is herbal products and botanicals. This review presents a comprehensive and specialized view of in vivo studies of herbal plants in poultry species. Many herbal extracts as Nigella sativa oil, Astragalus, Cochinchina momordica and Sargassum pallidum polysaccharides proved very effective as adjuvants for AIV vaccines. Another beneficial role of herbs is enhancement of host response to vaccination with further better prevention of infection and easier control. For enumeration not inventory, this is best achieved with the use of virgin coconut oil, Echinacea purpurea, Ginseng stem-and-leaf saponins (GSLS), Astragalus polysaccharides (APS), Myrtus communis oil, Garlic powder, Turmeric, Thyme and Curcumin. This review aimed to evaluate most of the in vivo studies performed on poultry species as a step and a guide for scientists and field practitioners in establishment of new effective herbal-based drugs for prevention and control of AIV in poultry.

Total Astragalus saponins attenuates CVB3-induced viral myocarditis through inhibiting expression of tumor necrosis factor α and Fas ligand

Background

To investigate the therapeutic effect of total Astragalus saponins (AST) against viral myocarditis in animal and cell models.

Methods

Primary myocardiocytes (PMCs) were stimulated by the coxsackie B (CVB) 3 virus to prepare the cell model of viral myocarditis. Cell viability, apoptosis and the mRNA expression of C-Myc, tumor necrosis factor (TNF)-α and Fas were detected to evaluate the protective effects of AST on CVB3-induced PMC damage.

Results

AST could significantly increase survival and decrease the ratio of heart weight: body weight (P<0.05). The level of myocardial fibrosis in the AST group was significantly lower than that in the CVB3 group. Compared with the CVB3 group, the ejection fraction was increased significantly in the AST group. Levels of lactate dehydrogenase and creatine kinase-MB in the peripheral blood of the AST group were significantly lower than those in the control group. In vitro, AST could significantly decrease CVB3-induced PMC apoptosis. Expression of C-Myc, TNF-α, Fas in the AST group was significantly lower than that in the CVB3 group.

Conclusions

It is demonstrated that AST was protective against CVB3-induced viral myocarditis, which may be associated with a decrease in CVB3-induced apoptosis and down-regulation of expression of C-Myc, TNF-α and Fas.

Polysaccharides as vaccine adjuvants

Adjuvant is a substance added to vaccine to improve the immunogenicity of antigens, and it can induce stronger immune responses and reduce the dosage and production cost of vaccine in populations responding poorly to vaccination. Adjuvants in development or in use mainly include aluminum salts, oil emulsions, saponins, immune-stimulating complexes, liposomes, microparticles, nonionic block copolymers, polysaccharides, cytokines and bacterial derivatives. Polysaccharide adjuvants have attracted much attention in the preparation of nano vaccines and nano drugs because natural polysaccharides have the characteristics of intrinsic immunomodulating, biocompatibility, biodegradability, low toxicity and safety. Moreover, it has been proved that a variety of natural polysaccharides possess better immune promoting effects, and they can enhance the effects of humoral, cellular and mucosal immunities. In the present study, we systematically reviewed the recent studies on polysaccharides with vaccine adjuvant activities, including chitosan-based nanoparticles (NPs), glucan, mannose, inulin polysaccharide and Chinese medicinal herb polysaccharide. The application and future perspectives of polysaccharides as adjuvants were also discussed. These findings lay a foundation for the further development of polysaccharide adjuvants. Collectively, more and more polysaccharide adjuvants will be developed and widely used in clinical practice with more in-depth investigations of polysaccharide adjuvants.

Tumor necrosis factor-α-induced protein 8-like-2 is involved in the activation of macrophages by Astragalus polysaccharides in vitro

In previous years, studies have shown that Astragalus polysaccharides (APS) can improve cellular immunity and humoral immune function, which has become a focus of investigations. Tumor necrosis factor‑α‑induced protein 8‑like 2 (TIPE2) is a negative regulator of immune reactions. However, the effect and underlying mechanisms of TIPE2 on the APS‑induced immune response remains to be fully elucidated. The present study aimed to examine the role of TIPE2 and its underlying mechanisms in the APS‑induced immune response. The production of nitric oxide (NO) was detected in macrophages in vitro following APS stimulation. In addition, the present study interfered with the expression of TIPE2 in macrophages, and examined the production of cytokines, NO and components of the mitogen‑activate protein kinase (MAPK) signaling pathway following APS stimulation. The results showed that APS was able to activate macrophages by inducing the production of interleukin (IL)‑1β, tumor necrosis factor (TNF)‑α, IL‑6 and NO. Furthermore, RAW264.7 cells were stimulated with APS when TIPE2 was silenced, and it was found that the production of TNF‑α, IL‑6, IL‑1β and NO were upregulated, and the signaling pathway of MAPK was activated. Taken together, these results demonstrated that TIPE2 had an important negative effect on the APS‑induced production of inflammatory cytokines and NO via the MAPK signaling pathway.

Astragalus polysaccharides enhance the immune response to avian infectious bronchitis virus vaccination in chickens

Astragalus polysaccharides (APS) are biological macromolecules extracted from Astragalus species that have strong immunoregulatory properties. In this study, APS were employed as an adjuvant for an avian infectious bronchitis virus (IBV) vaccine, and its effects on the cellular immune and humoral immune responses to vaccination in chicken were investigated. One hundred and fifty chicken were randomly divided into five groups (n = 30, each group). The chickens in all groups, except for the unvaccinated control group, were vaccinated with an IBV DNA vaccine. Three of the four vaccinated groups were administered different doses of APS (APSL, 10 mg/kg; APSM, 50 mg/kg; and APSH, 100 mg/kg) after the first vaccination, and the remaining vaccinated group served as a control, without any additional treatment. At 14, 28, and 42 days after the first vaccination, serum anti-IBV antibody titers; peripheral lymphocyte proliferation; and the mRNA expression of IL-1β, IL-2, IL-8, and TNF-α in the spleen were assessed by enzyme-linked immunosorbent assay (ELISA), the cell counting kit-8 (CCK-8), and real time quantitative RT-PCR (qRT-PCR), respectively. At most time points, the titer of IBV-specific antibodies, lymphocyte proliferation, and IL-1β, IL-2, IL-8, and TNF-α mRNA expression levels were higher in three APS groups than in the vaccine control group, and these increases were dose-dependent. These data suggest that APS could be used as an adjuvant for IBV vaccination to provide better protection against IBV infection.