(1→3)-β-d-Glucans as biological response modifiers: a review of structure-functional activity relationships

The Effect of Mushroom Beta-Glucans from Solid Culture of Ganoderma lucidum on Inhibition of the Primary Tumor Metastasis

This study evaluates the effect of mushroom beta-glucans (MBGS) derived from solid culture of Ganoderma lucidum on tumor inhibition by examining size of the primary tumor and rate of metastasis in Lewis lung carcinoma (LLC) bearing mice (C57BL/6), given oral administration of MBGS with radiation therapy. A previous result showed that MBGS enhances NK cell-mediated cytotoxicity in mice without LLC bearing in advance. Furthermore, applications of MBGS in conjunction with radiation therapy were effective in controlling tumor growth, and rate of metastasis, life threatening, and can potentially serve as a protective factor for wounds and hair loss that resulted from the overgrowth of primary tumor in LLC bearing mice.

Valuation of brewers spent yeast polysaccharides: a structural characterization approach

Brewers spent yeast (BSY) is a by-product from beer industry that can be exploited as source of glucans and mannoproteins, with potential biological activities. In order to solubilize these carbohydrate-rich polymeric materials, a sequential extraction with hot water and alkaline solutions (0.1-8 M KOH) was performed. Mannoproteins were mainly (85%) extracted with 4 M KOH whereas glucans were extracted with 8 M KOH and in an amount that accounted only for 34% of total glucose. Final residue still accounted for 34% of the initial glucans and contained 98% of glucose. Cellulase and α-amylase treatments showed the presence of both α- and β-(1→4)-Glc linkages. To promote total solubilization of these insoluble glucans, the final residue was submitted to a partial acid hydrolysis. This work is the first report showing that the most abundant polysaccharides in BSY are polymers that contain structural features similar to cellulose, thus justifying their resistance to alkaline extractions, acid hydrolysis, and insolubility in water.

Antioxidant activities of the oligosaccharides from the roots, flowers and leaves of Panax ginseng C.A. Meyer

The chemical characterization and antioxidant activities of water-soluble ginseng oligosaccharides from roots (WGOS-R), flowers (WGOS-F) and leaves (WGOS-L) of Panax ginseng C.A. Meyer obtained by hot water extraction were investigated. The sugar content of WGOS-R, WGOS-F and WGOS-L were 95.87%, 87.07% and 83.09%, respectively. The ginsenosides and total phenols content decreased in the order of WGOS-L>WGOS-F>WGOS-R. WGOS-R comprised only Glc, WGOS-F and WGOS-L comprised Glucose (Glc) and Rhamnose (Rha) in a molar ratio of 6.0:1.0 and 7.0:1.0, respectively. In vitro antioxidant tests showed that WGOS-R exhibited higher antioxidant activity than WGOS-F and WGOS-L. In vivo antioxidant tests showed that WGOS-R significantly enhanced activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px) and total antioxidant capability (T-AOC) in the serum and liver and decreased malondialdehyde (MDA) level in the serum and liver.

β-D-glucan inhibits endocrine-resistant breast cancer cell proliferation and alters gene expression

Endocrine therapies have been successfully used for breast cancer patients with estrogen receptor α (ERα) positive tumors, but ∼40% of patients relapse due to endocrine resistance. β-glucans are components of plant cell walls that have immunomodulatory and anticancer activity. The objective of this study was to examine the activity of β-D-glucan, purified from barley, in endocrine-sensitive MCF-7 versus endocrine-resistant LCC9 and LY2 breast cancer cells. β-D-glucan dissolved in DMSO but not water inhibited MCF-7 cell proliferation in a concentration-dependent manner as measured by BrdU incorporation with an IC₅₀ of ∼164±12 μg/ml. β-D-glucan dissolved in DMSO inhibited tamoxifen/endocrine-resistant LCC9 and LY2 cell proliferation with IC₅₀ values of 4.6±0.3 and 24.2±1.4 μg/ml, respectively. MCF-10A normal breast epithelial cells showed a higher IC₅₀ ∼464 μg/ml and the proliferation of MDA-MB-231 triple negative breast cancer cells was not inhibited by β-D-glucan. Concentration-dependent increases in the BAX/BCL2 ratio and cell death with β-D-glucan were observed in MCF-7 and LCC9 cells. PCR array analysis revealed changes in gene expression in response to 24-h treatment with 10 or 50 μg/ml β-D-glucan that were different between MCF-7 and LCC9 cells as well as differences in basal gene expression between the two cell lines. Select results were confirmed by quantitative real-time PCR demonstrating that β-D-glucan increased RASSF1 expression in MCF-7 cells and IGFBP3, CTNNB1 and ERβ transcript expression in LCC9 cells. Our data indicate that β-D-glucan regulates breast cancer-relevant gene expression and may be useful for inhibiting endocrine-resistant breast cancer cell proliferation.

Extraction optimization and antinociceptive activity of (1→3)-β-d-glucan from Rhodotorulamucilaginosa

β-d-glucans are polymers of d-glucose monomers found in the cell walls of many bacteria, plants, fungi and yeasts. A variety of β-d-glucans differing in structures have been isolated from various sources and their biological activity to be regulated by various structural factors, such as the primary structure, molecular weight, solubility, and conformation. This study investigated the effect of extraction time and temperature on the yield of β-d-glucan produced by Rhodotorulamucilaginosa. A statistical Doehlert design was applied to determine the important effects and interactions of these independent variables on the yield of β-d-glucan, the dependent variable. Significant models were obtained. The best yield was of 25% obtained after 128min of extraction in a temperature of 72°C. The polysaccharides were characterized as (1⟶3)-β-d-glucan by methods spectroscopic (FT-IR, (1)HNMR and (13)CNMR). In addition, the antinociceptive effect was evaluated using different experimental tests (acetic acid-induced writhing test, formalin test and tail immersion test). The (1⟶3)-β-d-glucan showed a potent peripheral antinociceptive effect, possibly by the inhibition of inflammatory mediators.

Concentration variation and molecular characteristics of soluble (1,3;1,6)-β-D-glucans in submerged cultivation products of Ganoderma lucidum mycelium

(1,3)-β-D-Glucans with (1,6)-β-D-glucosyl branches are bioactive polysaccharides in fruiting bodies and mycelia of Ganoderma lucidum, a mushroom used in traditional Chinese medicine. Submerged cultivation of mycelium is one of the more efficient means of generating polysaccharides from this fungus. Twelve mycelium samples examined in this study demonstrated the quantitative and qualitative molecular characteristics of soluble (1,3;1,6)-β-D-glucans. It was observed that the concentration of soluble (1,3;1,6)-β-D-glucan varied substantially from 1.3 to 79.9 mg/dL. (1,3;1,6)-β-D-Glucans also preserved their molecular characteristics with degrees of branching (DB) of 0.21-0.36 and molecular masses of 10(5)-10(6) g/mol for those samples with substantial quantities of β-D-glucan. Using the high aggregating tendency of these molecules, (1,3;1,6)-β-D-glucans were successfully purified via fractional precipitation with 35% (v/v) ethanol. (1,3;1,6)-β-D-Glucan was proposed as a putative bioactive marker for immunomodulation because it was the most abundant polysaccharide in G. lucidum mycelium products to stimulate macrophage RAW 264.7 cells to release TNF-α.

Isolation and characterization of extracellular polysaccharide Thelebolan produced by a newly isolated psychrophilic Antarctic fungus Thelebolus

The present investigation is on a newly isolated psychrophilic Antarctic filamentous Ascomycetous fungus that has been identified as Thelebolus sp. and given the designation of Thelebolus sp. IITKGP-BT12. The culture was primarily identified through morphological studies, and was further confirmed by 18S rRNA sequencing (GenBank Accession No. KC191572), which revealed its close relatedness with Thelebolus microsporus. The exopolysaccharide (EPS) produced (1.94 g L(-1)) by the fungus was isolated, purified and characterized as glucan having an average molecular mass of 5×10(5)Da. The structure of EPS was determined by gas chromatography with tandem mass spectrometry (GC-MS/MS), Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance (NMR) studies ((1)H, (13)C and HSQC). NMR analysis indicated the presence of (1→3)-linked β-d-glucan backbone with (1→6)-linked branches of β-d-glucopyranosyl units. Antiproliferative activity of EPS was demonstrated in B16-F0 cells, with IC50 of 275.42 μg m L(-1). Flow cytometry analysis and DNA fragmentation studies revealed that the cytotoxic action of the EPS mediated apoptosis in cancer cells. This is the first ever report on bioactive EPS thelebolan from Thelebolus sp.

Facile preparation of highly crystalline lamellae of (1 → 3)-β-D-glucan using an extract of Euglena gracilis

In vitro synthesis of (1 → 3)-β-D-glucan was performed using laminaribiose phosphorylase obtained by an extraction of Euglena gracilis with sucrose phosphorylase. The synthetic product was a linear (1 → 3)-β-D-glucan with a narrow distribution of degree of polymerization (DP) centered on DP=30. X-ray diffraction and electron microscopy revealed that the glucan molecules obtained were self-organized as highly crystalline hexagonal lamellae. This synthetic product has quite high structural homogeneity at every level from primary to higher-order structure, which is a great advantage for the detailed analyses of physiological functions of (1 → 3)-β-D-glucan.

Enhancement of intestinal immune function in mice by β-D-glucan from aureobasidium pullulans ADK-34

β-Glucans, glucose polymers that are the main constituents of the outer cell walls of micro-organisms such as fungi and yeast, are known to play an immunostimulatory role. We prepared β-glucan (β-(1-3),(1-6)-D-glucan) from an edible cultured fungus through fermentation techniques using a strain of Aureobasidium pullulans ADK-34. The purity of this β-glucan preparation (AP-FBG) was demonstrated to be high through various instrumental analyses. We then examined the effects of AP-FBG on intestinal immune systems. We prepared Peyer's patch (PP) cells and measured interleukin (IL)-5, IL-6, and IgA production in culture media with AP-FBG. We found that both cytokines and IgA increased; furthermore, IL-6 secreted by PP dendritic cells (PPDCs) cultured in the presence of AP-FBG significantly increased. We tested IgA production after oral administration of AP-FBG for 2 weeks and found that AP-FBG tended to promote the production of IgA in the small intestine. Interestingly, we observed a significant increase in IgA production in the small intestines of mice treated with cyclophosphamide (CY; an immunosuppressant) after oral administration of AP-FBG diet compared with CY-treated and control diet mice. Production of IL-6 and IgA by PP cells and IL-6 production by PPDCs in AP-FBG-fed and CY-treated mice also increased. These results demonstrate that AP-FBG has the ability to activate PPDC and induce IL-6 production and IgA secretion in PP cells. These abilities were more clearly expressed when AP-FBG was orally administered in a CY-induced immunosuppressed condition. Therefore, AP-FBG may be a useful ingredient for preparing functional foods with immunomodulatory activities.

β-glucan enriched bath directly stimulates the wound healing process in common carp (Cyprinus carpio L.)

Wound healing is a complex and well-organized process in which physiological factors and immune mechanisms are involved. A number of different immune modulators have been found to enhance the non-specific defence system in vertebrates, among which β-glucans are the most powerful and extensively investigated. The aim of the present study was to investigate the biological impact of two different commercially available β glucan containing products on the wound healing process in carp. Throughout a two week experiment fish were kept either untreated (control), or in water supplemented with the two different types of β-glucans. The wound healing process was monitored using a multispectral visualisation system. The correlation between wound closure and immune response was investigated by measuring the gene expression patterns of IL-1β, IL-6 family member M17, IL-8 and Muc5b, and measurement of production of radical oxygen species. PAMPs/DAMPs stimulation caused by the wounding and or β-glucans resulted in an inflammatory response by activating IL-1β, IL-6 family member M17 and IL-8 and differences in the expression pattern were seen depending on stimuli. IL-1β, IL-6 family member M17 and IL-8 were activated in all wounds regardless of treatment. Expression of all three interleukins was highly up regulated in control wounded muscle already at day 1 post-wounding and decreased at subsequent time-points. The reverse was the case with control wounded skin, where expression increased from day 1 through day 14. The results for the β-glucan treated wounds were more complex. The images showed significantly faster wound contraction in both treated groups compared to the control. The obtained results clearly demonstrated that a β glucan enriched bath promotes the closure of wounds in common carp and induce a local change in cytokine expression.

Solid-State 13C CP MAS NMR Spectroscopy as a Tool for Detection of (1→3, 1→6)-β-D-Glucan in Products Prepared from Pleurotus ostreatus

The 13C CP/MAS NMR solid-state NMR technique was used to detect the presence of β-D-glucan and trace compounds in samples prepared from dried, naturally grown oyster mushroom (Pleurotus ostreatus) and commercially available products of dried, specially cultivated oyster mushroom and β-D-glucan isolated from this mushroom. The NMR spectra of all samples displayed signals typical for (1→3, 1→6)-β-D-glucan; however, signals which could be assigned to other trace compounds—(1→3)-α-glucan, chitin, and proteins—were also observed in the spectra. The amount of trace compounds was negligible in the commercially available products.

Structural characterisation of polysaccharides from Tricholoma matsutake and their antioxidant and antitumour activities

In this study, polysaccharides from Tricholoma matsutake (TM-P) were purified using a DEAE-Sepharose fast flow column and three polysaccharide fractions (TM-P1, TM-P2 and TM-P3) were obtained. The chemical composition and structural characteristics of TM-P2 were quite different from those of TM-P1 and TM-P3. TM-P2 consisted of glucose, galactose and mannose with a molar ratio of 5.9:1.1:1.0. The glycosidic linkages were mainly composed of 1,6- and 1-linked glucose. Furthermore, TM-P2 showed the strongest in vitro antioxidant and antitumour activities. The oxygen radical absorbance capacity (ORAC) of TM-P2 was 2100.44 μmol Trolox/g. The antiproliferative activities of TM-P2 (4.0mg/ml) on the growth of HepG2 and A549 cells were 67.98% and 59.04%, respectively.

Dietary (1,3/1,6)-β-D-glucan decreases transforming growth factor β expression in the lung of the neonatal piglet

Identification and characterization of compounds that enhance the growth, development, and health of infants who are not breastfed continues to be a goal for nutritional science. This study explored the effects of one dietary component, (1,3/1,6)-β-D-glucan (Wellmune WGP), on lung immune development in the neonatal piglet. The hypothesis was that supplementation with WGP, a pathogen-associated molecular pattern, would enhance pathogen-responsive elements of the immune system, for instance, by increasing the size of the cytotoxic T-cell population or the expression of inflammatory cytokines. Piglets were fed a control formula or formula plus WGP at 1.8, 18, or 90 mg/kg body weight per day. Serum, thoracic lymph nodes (TLNs), mediastinal lymph nodes, and lung were collected at days 7 or 21. Immune parameters including tissue messenger RNA (mRNA) expression and T-cell phenotypes were analyzed. Normal developmental changes were observed, with a decrease in T-helper cells and an increase in cytotoxic T cells in both TLN and mediastinal lymph node, but there was no effect of WGP. Dietary WGP reduced the mRNA expression of transforming growth factor (TGF) β2 and tended to reduce the mRNA expression of TGF-β1 in lung tissue. With the exception of reducing TGF-β mRNA in the lung and tending to decrease the ratio of T helper to cytotoxic T cell in the TLN, dietary WGP did not affect lung-associated adaptive immunity in piglets.

Successful therapy of visceral leishmaniasis with curdlan involves T-helper 17 cytokines

The aim of this study was to evaluate and characterize the therapeutic potential of curdlan, a naturally occurring β-glucan immunomodulator, against visceral leishmaniasis, a fatal parasitic disease. Curdlan eliminated the liver and spleen parasite burden in a 45-day BALB/c mouse model of visceral leishmaniasis at a dosage of 10 mg/kg/day as determined by Giemsa-stained organ impression smears. Curdlan was associated with production of the disease-resolving T-helper (Th) 1 and Th17-inducing cytokines interleukin (IL)-6, IL-1β, and IL-23, as well as with production of Th17 cytokines IL-17 and IL-22, as determined by enzyme-linked immunosorbent assay (ELISA) and real time polymerase chain reaction (RT-PCR). Reversal of curdlan-mediated protection by anti-IL-17 and anti-IL-23 monoclonal antibodies showed the importance of Th17 cytokines. Significantly decreased production of both IL-17 and IL-22 by mice that received anti-IL-23 antibody suggested the essential role of IL-23 in Th17 differentiation. Although administration of recombinant IL-17 or IL-23 caused significant suppression of the organ parasite burden, with marked generation of interferon γ and nitric oxide (NO), effects were much faster for IL-17. These results documented that although both IL-23 and IL-17 play major roles in the antileishmanial effect of curdlan, the effect of IL-23 may occur indirectly, through the induction of IL-17 production.

Characterization and lectin microarray of an immunomodulatory heteroglucan from Pleurotus ostreatus mycelia

Glucans isolated from various mushroom and mycelia sources are interestingly being studied nowadays as a potent therapeutic agent. The present work was focused on the isolation, characterization and immunomodulatory study of a novel water soluble glucan from the pure mycelia of Pleurotus ostreatus. The extracted glucan was found to have a high molecular weight of ∼2.7 × 10(6)Da and mainly comprised of glucose, mannose and fucose in a ratio of 3:2:1 with both β and α linkages. Presence of terminal or interior glucose, mannose and fucose residues was also revealed using a high throughput miniaturized platform of lectin microarray. The heteroglucan folded into a triple helical conformation and exhibited enhanced immune cell activation and anti-tumor potential in tumor bearing mice model. Thus, potential biological functions incorporated in these glucan molecules acts in accord with its structural property and exploration of such structure-function relationship will unveil its diverse mechanism of action.

Lactarius rufus (1→3),(1→6)-β-D-glucans: structure, antinociceptive and anti-inflammatory effects

Medicinal health benefits uses of edible as well as non-edible mushrooms have been long recognized. The pharmacological potential of mushrooms, especially antitumor, immunostimulatory and anti-inflammatory activities has been documented. Wild ectomycorrhizal mushroom, Lactarius rufus had the anti-inflammatory and antinociceptive potential of their polysaccharides evaluated using the formalin model. Two structurally different (1→3),(1→6)-linked β-D-glucans were isolated from fruiting bodies. Soluble (FSHW) β-D-glucan 1-30 mg kg(-1) produced potent inhibition of inflammatory pain caused by formalin when compared with the insoluble one (IHW), suggesting that solubility and/or branching degree could alter the activity of β-glucans. Their structures were determined using mono- and bi-dimensional NMR spectroscopy, methylation analysis, and controlled Smith degradation. They were β-D-glucans, with a main chain of (1→3)-linked Glcp residues, substituted at O-6 by single-unit Glcp side chains (IHW), on average to every fourth residue of the backbone, or by mono- and few oligosaccharide side chains for soluble β-glucan.