Structural analysis of an alkali-extractable and water-soluble polysaccharide (ABP-AW1) from the fruiting bodies of Agaricus blazei Murill

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.

Polysaccharides and extracts from Agaricus brasiliensis Murill - A comprehensive review

Edible mushrooms have been increasingly introduced into the human diet, which has driven research into their functional properties. Thus, Agaricus brasiliensis Murill or Agaricus blazei Murill (ABM) is a species native to the Brazilian biome, whose fruiting body has been used not only for dietary purposes, but also in the development of functional foods or as source of molecules of pharmacological interest. The bioactivity of ABM has been related to the presence of polysaccharides, although the contribution of other metabolites cannot be discharged. This work describes the polysaccharides isolation methodology and preparation of the extracts of ABM and their biological activities. Furthermore, it presents a general outline of its characterizations regarding composition, chemical structure and properties in solution. The ABM and its chemical constituents exhibit several biological activities that support their potential use for prevention or treatment of diseases with inflammatory background, such as cancer, diabetes and atherosclerosis. The mechanism of action of the extracts and polysaccharides from ABM is mainly related to a modulation of immune system response or reduction of inflammatory response. This review shows that the ABM has great potential in the pharmaceutical, biotechnological and food sectors that deserves additional research using standardized products.

Antiviral activity of a polysaccharide from Radix Isatidis (Isatis indigotica Fortune) against hepatitis B virus (HBV) in vitro via activation of JAK/STAT signal pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Hepatitis B virus (HBV) infection frequently results in both acute and chronic hepatitis and poses serious threats to human health worldwide. Despite the availability of effective HBV vaccine and anti-HBV drugs, apparently inevitable side effects and resistance have limited its efficiency, thus prompt the search for new anti-HBV agents. The traditional Chinese medicine Radix Isatidis has been used for thousands of years, mainly for the treatment of viral and bacterial infection diseases including hepatitis.

AIM OF THE STUDY

In this study, antiviral activities of a Radix Isatidis (Isatis indigotica Fortune) polysaccharide (RIP) were evaluated in vitro model using the HepG2.2.15 cell line and the underlying mechanism was elucidated with the aim of developing a novel anti-HBV therapeutic agent.

MATERIALS AND METHODS

Structure features of the purified polysaccharide RIP were investigated by a combination of chemical and instrumental analysis. Drug cytotoxicity was assessed using the MTT assay. The contents of HBsAg, HBeAg, intracellular and extracellular IFN-α level were measured using respective commercially available ELISA kit. The HBV DNA expression was evaluated by real-time quantitative polymerase chain reaction (PCR) and the relevant proteins involved in TFN/JAK/STAT signaling pathways were examined by western blot assay.

RESULTS

MTT assay showed that RIP had no toxicity on HepG2.2.15 cell line below the concentration 400 μg/ml at Day 3, 6 and 9. Furthermore, RIP at the concentration of 50, 100 and 200 μg/ml significantly reduced extracellular and intracellular level of HBsAg, HBeAg and HBV DNA in HepG2.2.15 cells in a time and dose-dependent manner. Moreover, RIP also enhanced the production of IFN-α in HepG2.2.15 cell via activation of JAK/STAT signal pathway and induction of antiviral proteins, as evidenced by the increased protein expression of p-STAT-1, p-STAT-2, p-JAK1, p-TYK2, OAS1, and Mx in HepG2.2.15 cells. In addition, the over expression of SOCS-1 and SOCS-3 was significantly abolished under same conditions.

CONCLUSIONS

These results suggested that the HBV inhibitory effect of RIP was possibly due to the activation of IFN-α-dependent JAK/STAT signal pathway and induction of the anti-HBV protein expression.

Antibacterial potential of Forsythia suspensa polysaccharide against resistant Enterobacter cloacae with SHV-12 extended-spectrum β-lactamase (ESBL)

In this study, a homogenous polysaccharide (FSP), with an average molecular weight of 9.08 × 10⁴ Da, was isolated from Forsythia suspense and its antibacterial potential against Enterobacter cloacae producing SHV‐12 ESBL was investigated. Growth kinetics, in vitro competition and biofilm formation experiments demonstrated that SHV‐12 ESBL contributed to a fitness benefit to E cloacae strain. The antibacterial activity of FSP (2.5, 5.0 and 10.0 μg/mL) was tested against E cloacae bearing SHV‐12 ESBL gene using bacterial sensitivity, agar bioassay and agar well diffusion assays. It was found that the addition of FSP demonstrated potent antibacterial activities against this bacterial as showed by the decrease of bacterial growth and the increase of the inhibition zone diameter. Furthermore, SHV‐12 ESBL gene expression was decreased in E cloacae strain following different FSP treatment in a concentration‐dependent manner. In conclusion, these data showed that FSP exhibited potent good antibacterial activity against E cloacae producing SHV‐12 ESBL via inhibition of SHV‐12 ESBL gene expression, which may promote the development of novel natural antibacterial agents to treat infections caused by this drug‐resistant bacterial pathogen.

Discovery of a polysaccharide from the fruiting bodies of Lepista sordida as potent inhibitors of indoleamine 2, 3-dioxygenase (IDO) in HepG2 cells via blocking of STAT1-mediated JAK-PKC-δ signaling pathways

The present study examined the role of a polysaccharide (LSP, 25 and 100 μg/ml) from the fruiting bodies of Lepista sordid on the immunosuppressive enzyme indoleamine 2, 3-dioxygenase (IDO) in HepG2 cells, and the possible mechanism of action. IDO expression and kynurenine production from LSP-treated HepG2 cells following IFN-γ stimulation were dramatically inhibited by LSP treatment. In line with this, the medium of HepG2 cells pretreated with LSP improved the survival rate of primary CD4+ and CD8+ T cells as compared with IFN-γ-treated control cells. Moreover, tyrosine 701 and serine 727 phosphorylation of STAT1 were dramatically reduced by LSP pretreatment in IFN-γ-stimulated HepG2 cells. Furthermore phosphorylation of JAK-1 and JAK-2 was also inhibited by LSP. Additionally, two IDO promoters (GAS and ISRE) were inhibited in cells pretreated with LSP prior to IFN-γ exposure. These findings suggest that LSP exerts antitumor effects on HepG2 cells by inhibiting IDO via JAK-PKC-δ-STAT1 signaling pathway.

Low-molecular-weight polysaccharides from Agaricus blazei Murrill modulate the Th1 response in cancer immunity

To assess the effect of low-molecular-weight polysaccharides from Agaricus blazei Murrill (ABP-AW1) as an immunoadjuvant therapy for type 1 T-helper (Th1) responses in tumorigenesis, C57BL/6 mice were inoculated subcutaneously with ovalbumin (E.G7-OVA). After 3, 10 and 17 days, the mice were immunized with PBS, OVA alone, or OVA and ABP-AW1, at low (50 µg), intermediate (100 µg) or high (200 µg) doses. Tumor growth was examined and compared among the groups, as were the following parameters: Splenocyte viability/proliferation, peripheral blood CD4⁺/CD8⁺ T cell ratio, serum OVA-specific IgG1 and IgG2b, secretion of interleukin (IL)-2 and interferon (IFN)-γ, and IFN-γ production on a single cell level from cultured splenocytes. Tumor growth in mice treated with OVA and ABP-AW1 (100 or 200 µg) was significantly slower, compared with in the other groups at the same time-points. OVA with 100 or 200 µg ABP-AW1 was associated with a higher number of total splenocytes, a higher ratio of peripheral blood CD4⁺/CD8⁺ T-lymphocytes, higher serum levels of OVA-specific Th1-type antibody IgG2b and greater secretion of the Th1 cytokines IL-1 and IFN-γ from splenocytes. ABP-AW1 is a promising immunoadjuvant therapy candidate, due to its ability to boost the Th1 immune response when co-administered with a cancer vaccine intended to inhibit cancer progression.

Structural characterization of low molecular weight polysaccharide from Astragalus membranaceus and its immunologic enhancement in recombinant protein vaccine against systemic candidiasis

Structure and immunologic enhancement of low molecular weight polysaccharide (LMW-ASP) isolated from the root of Astragalus membranaceus (Fisch) Bge. Were detected in recombinant protein vaccine. Structure analysis of LMW-ASP revealed that LMW-ASP (Mw=5.6kDa) was an acid heteropolysaccharide, which consisted of Glc, Gal, Ara, Xyl and GalA in ratio of 10.0：1.3：1.7：1.0：0.9. Recombinant protein (rP-HSP90C) contained epitope C (LKVIRK) from heat shock protein 90 (HSP90) of Candida albicans was used as a vaccine. The results indicated that LMW-ASP significantly promoted specific antibody titers IgG, IgG1, IgG2b, and IL-2, IL-4, IL-10, IL-12 in sera of mice immunized with rP-HSP90C (p<0.05). It was also found LMW-ASP improved DTH response in HSP90C-injceted mice. More importantly, the mice immunized with rP-HSP90C/LMW-ASP had fewer CFU (colony forming unites) in the kidneys compared to the mice immunized with rP-HSP90C (p<0.05). Therefore, LMW-ASP could be exploited into the novel adjuvant to enhance the efficacy of recombinant protein vaccine.

A polysaccharide isolated from Agaricus blazei Murill (ABP-AW1) as a potential Th1 immunity-stimulating adjuvant

In the present study, a low molecular weight polysaccharide, ABP-AW1, isolated from Agaricus blazei Murill was assessed for its potential adjuvant activity. ABP-AW1 is considered to create a ‘depot’ of antigen at a subcutaneous injection site. ICR mice were immunized with 100 μg ovalbumin (OVA) alone or with 100 μg OVA formulated in 0.9% saline containing 200 μg aluminum (alum) or ABP-AW1 (50, 100 and 200 μg) on days 1 and 15. Two weeks after the secondary immunization, splenocyte proliferation, the expression of surface markers, cytokine production and the OVA-specific antibody levels in the serum were determined. The OVA/ABP-AW1 vaccine, in comparison with OVA alone, markedly increased the proliferation of splenic lymphocytes and elicited greater antigen-specific CD4⁺ T cell activation, as determined by splenic CD4⁺CD69⁺ T cells and Th1 cytokine interferon (IFN)-γ release. The combination of ABP-AW1 and OVA also enhanced IgG2b antibody responses to OVA. In conclusion, these data indicated that ABP-AW1 significantly enhanced the humoral and cellular immune responses against OVA in the mice, suggesting that ABP-AW1 stimulated Th1-type immunity. We suggest that ABP-AW1 may serve as a new adjuvant.

Agaricus subrufescens: A review

Medicinal mushrooms have currently become a hot issue due to their various therapeutic properties. Of these, Agaricus subrufescens, also known as the "almond mushroom", has long been valued by many societies (i.e., Brazil, China, France, and USA). Since its discovery in 1893, this mushroom has been cultivated throughout the world, especially in Brazil where several strains of A. subrufescens have been developed and used as health food and alternative medicine. This article presents up-to-date information on this mushroom including its taxonomy and health promoting benefits. Medicinal properties of A. subrufescens are emphasized in several studies which are reviewed here. In addition, safety issues concerning the use of this fungus will be discussed.