Effects of water-soluble low-molecular-weight β-1, 3-D-glucan (branch β-1, 6) isolated from Aureobasidium pullulans 1A1 strain black yeast on restraint stress in mice

Microalgae-Derived Microparticles Improve Immunomodulation via Combined Glycolysis and MAPK Activation

Natural polysaccharides possess potent immunostimulatory properties, but their poor solubility impedes efficiency of cellular delivery. This study focuses on extraction of microparticles (MPs) fromEuglena gracilis, a microalgae species characterized by abundant intracellular β-1,3-glucan and flexible cell membrane. We introduce anE. gracilis-derived MP (MPEG) system as a natural carrier for solubilized β-glucan. The MPEG system enhances β-glucan's solubility and loading efficiency through sequential sonication and cell extrusion. In vitro studies reveal that MPEG utilizes multiple endocytosis pathways, including phagocytosis, clathrin-mediated, and lipid raft-mediated routes, for effective β-glucan delivery into cells. Upon cellular internalization, MPEG components trigger dual activation of the MAPK signaling pathway and glycolysis in macrophages, leading to enhanced production of pro-inflammatory cytokines and lactic acid, ultimately strengthening innate immune responses. This MPEG system offers a promising approach to harnessing the immunostimulatory properties of natural polysaccharides while overcoming their solubility limitations, opening new avenues for targeted cellular delivery in immunomodulation therapies.

Yolkin Ameliorates Effects of the Psychic Stress on the Contact Sensitivity, Cell Proliferation, and Cytokine Production in Mice

BACKGROUND

Prolonged psychic stress leads to immune suppression, which preferentially affects the cellular immune response. Yolkin is an egg-derived protein with firmly established immunoregulatory activities in rodent models.

OBJECTIVE

The aim of this work was to evaluate the effects of oral administration of yolkin, when mice experience prolonged exposure to immobilization stress, on in vivo and in vitro parameters of contact sensitivity (CS) to oxazolone (OXA).

MATERIALS AND METHODS

BALB/c mice were exposed to 5-day immobilization stress, followed by immunization with OXA. Yolkin was applied in drinking water during stress. Ear thickness and auricle histology, concanavalin A (Con A)- and lipopolysaccharide (LPS)-stimulated production of interferon-gamma (IFN γ) and interleukin 6 (IL-6) in splenocyte cultures, Con A-induced splenocyte proliferation, as well as serum corticosterone levels and thymocyte number were analyzed.

RESULTS

We showed that the treatment with stress alone led to a lower thymocyte number and a decreased thickness of the auricle skin. Control mice that were stressed also exhibited an increase in the number and area of pustules in the epidermis. The treatment of stressed mice with yolkin resulted in a partial normalization of several parameters that were lowered in stressed mice, such as auricle thickness, thymus cell content, Con A-induced splenocyte proliferation, production of IFN γ and IL-6. The serum levels of corticosterone were correlated with several histological parameters.

CONCLUSION

Oral administration of yolkin normalizes the antigen-specific and nonspecific parameters of the immune system altered by chronic psychic stress in mice.

Polysaccharides from a Fermented Beverage Induce Nitric Oxide and Cytokines in Murine Macrophage Cell Line

Super Ohtaka®, a fermented beverage of plant extracts, is prepared from approximately 50 kinds of fruits and vegetables. Natural fermentation is mainly performed by lactic acid bacteria (Leuconostoc spp.) and yeast (Zygosaccharomyces spp.). Four water-soluble polysaccharide fractions were obtained from Super Ohtaka® by dialysis, ion exchange chromatography, and gel filtration chromatography; these fractions were designated as OEP1-1, OEP1-2, OEP2, and OEP3. OEP1-1 is a polysaccharide composed solely of glucose. The other fractions contained polysaccharides composed of glucose, galactose, mannose, and a small amount of arabinose. OEP2 and OEP3 contained phosphorus, which was not detected in OEP1-1 and OEP1-2. Furthermore, the immunomodulatory activity of the polysaccharides was investigated in murine macrophage cell lines. OEP2 and OEP3 significantly induced nitric oxide (NO) secretion by macrophages in a dose-dependent manner (concentration range of 4 to 100 µg/mL). When the concentration of OEP3 was 100 µg/mL, NO production was almost identical to lipopolysaccharide (LPS; 10 ng/mL) used as a positive control. Notably, OEP3 induced NO secretion more strongly than OEP2. This trend was also observed for TNF-α, IL-1β, IL-6, and IL-12 p40 secretion. Overall, our in vitro studies on polysaccharides isolated from Super Ohtaka® suggest that the fermented beverage stimulates macrophages and activates the immune system.

Pleurotus sajor-caju (Fr.) Singer β-1,3-Glucanoligosaccharide (Ps-GOS) Suppresses RANKL-Induced Osteoclast Differentiation and Function in Pre-Osteoclastic RAW 264.7 Cells by Inhibiting the RANK/NFκB/cFOS/NFATc1 Signalling Pathway

Edible grey oyster mushroom, Pleurotus sajor-caju, β (1,3), (1,6) glucan possesses a wide range of biological activities, including anti-inflammation, anti-microorganism and antioxidant. However, its biological activity is limited by low water solubility resulting from its high molecular weight. Our previous study demonstrated that enzymatic hydrolysis of grey oyster mushroom β-glucan using Hevea β-1,3-glucanase isozymes obtains a lower molecular weight and higher water solubility, Pleurotus sajor-caju glucanoligosaccharide (Ps-GOS). Additionally, Ps-GOS potentially reduces osteoporosis by enhancing osteoblast-bone formation, whereas its effect on osteoclast-bone resorption remains unknown. Therefore, our study investigated the modulatory activities and underlying mechanism of Ps-GOS on Receptor activator of nuclear factor kappa-Β ligand (RANKL) -induced osteoclastogenesis in pre-osteoclastic RAW 264.7 cells. Cell cytotoxicity of Ps-GOS on RAW 264.7 cells was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay and its effect on osteoclast differentiation was determined by tartrate-resistant acid phosphatase (TRAP) staining. Additionally, its effect on osteoclast bone-resorptive ability was detected by pit formation assay. The osteoclastogenic-related factors were assessed by quantitative reverse transcriptase polymerase chain reaction (qRT-PCR), Western blot and immunofluorescence. The results revealed that Ps-GOS was non-toxic and significantly suppressed the formation of mature osteoclast multinucleated cells and their resorption activity by reducing the number of TRAP-positive cells and pit formation areas in a dose-dependent manner. Additionally, Ps-GOS attenuated the nuclear factor kappa light chain-enhancer of activated B cells' P65 (NFκB-P65) expression and their subsequent master osteoclast modulators, including nuclear factor of activated T cell c1 (NFATc1) and Fos proto-oncogene (cFOS) via the NF-κB pathway. Furthermore, Ps-GOS markedly inhibited RANK expression, which serves as an initial transmitter of many osteoclastogenesis-related cascades and inhibited proteolytic enzymes, including TRAP, matrix metallopeptidase 9 (MMP-9) and cathepsin K (CTK). These findings indicate that Ps-GOS could potentially be beneficial as an effective natural agent for bone metabolic disease.

Preparation and characterization of carboxymethylated Aureobasidium pullulans β-(1 → 3, 1 → 6)-glucan and its in vitro antioxidant activity

Aureobasidium pullulans β-(1 → 3, 1 → 6)-glucan (APG) has a high degree of β-(1 → 6)-glucosyl branching and a regular triple helical structure similar to that of schizophyllan. In this study, APG was carboxymethylated to different degrees of substitution (DS = 0.51, 1.0, and 2.0, denoted CMAPG 1-3, respectively) using a heterogeneous reaction. With increasing DS, the triple-helix structure drastically decreased and converted to a random coil structure in CMAPG 3. Further, aqueous solutions of CMAPG changed from pseudoplastic fluids to perfect Newtonian liquids with increasing DS, indicating that the intra- and intermolecular hydrogen bonds had been cleaved by the substituents to form a random coil structure. In addition, APG and CMAPG solutions exhibited scavenging ability against hydroxyl, organic, and sulfate radicals. It was also found that the carboxymethylation of APG drastically enhanced the organic radical scavenging ability. On the basis of the relationship between the DS and radical scavenging ability of the CMAPG samples, we believe hydroxyl and organic radicals were preferably scavenged by the donation of hydrogen atoms from the glucose rings and the methylene moieties of the carboxymethyl groups, respectively. Considering the obtained results, CMAPG and APG are expected to have applications in pharmaceuticals, functional foods, and cosmetics as antioxidant polysaccharides.

Anti-inflammatory effects of β-1,3-1,6-glucan derived from black yeast Aureobasidium pullulans in RAW264.7 cells

β-glucan derived from the black yeast Aureobasidium pullulans (A. pullulans) is one of the natural products attracting attention due to its high potential for application as a functional food and pharmaceutical. Our team of researchers obtained a highly soluble, low-molecular-weight β-glucan from the fermentation culture medium of A. pullulans via mechanochemical ball milling method, that is, the low-molecular-weight A. pullulans-fermented β-D-glucan (LMW-AP-FBG). We investigated the anti-inflammatory effect of LMW-AP-FBG using lipopolysaccharide (LPS)-stimulated murine macrophages (RAW264.7 cells) in the current study. LMW-AP-FBG altered LPS-stimulated inflammatory responses by reducing the release of inflammatory mediators such as nitric oxide (NO), interleukin (IL)-1β, IL-6 and tumor necrosis factor-α. As well, the mitogen-activated protein kinases (MAPKs) and nuclear factor-κB (NF-κB) signaling pathways were downregulated by LMW-AP-FBG. Furthermore, LMW-AP-FBG markedly reduced LPS-induced expression of cell surface molecules, CD14, CD86, and MHC class II, which mediate macrophage activation. These findings suggest that LMW-AP-FBG can be used as an effective immune modulator to attenuate the progression of inflammatory disease.

Biological Activity of High-Purity β-1,3-1,6-Glucan Derived from the Black Yeast Aureobasidium pullulans: A Literature Review

The black yeast Aureobasidium pullulans produces abundant soluble β-1,3-1,6-glucan-a functional food ingredient with known health benefits. For use as a food material, soluble β-1,3-1,6-glucan is produced via fermentation using sucrose as the carbon source. Various functionalities of β-1,3-1,6-glucan have been reported, including its immunomodulatory effect, particularly in the intestine. It also exhibits antitumor and antimetastatic effects, alleviates influenza and food allergies, and relieves stress. Moreover, it reduces the risk of lifestyle-related diseases by protecting the intestinal mucosa, reducing fat, lowering postprandial blood glucose, promoting bone health, and healing gastric ulcers. Furthermore, it induces heat shock protein 70. Clinical studies have reported the antiallergic and triglyceride-reducing effects of β-1,3-1,6-glucan, which are indicators of improvement in lifestyle-related diseases. The primary and higher-order structures of β-1,3-1,6-glucan have been elucidated. Specifically, it comprises a single highly-branched glucose residue with the β-1,6 bond (70% or more) on a backbone of glucose with 1,3-β bonds. β-Glucan shows a triple helical structure, and studies on its use as a drug delivery system have been actively conducted. β-Glucan in combination with anti-inflammatory substances or fullerenes can be used to target macrophages. Based on its health functionality, β-1,3-1,6-glucan is an interesting material as both food and medicine.

Single-stranded β-1,3-1,6-glucan as a carrier for improved dissolution and membrane permeation of poorly water-soluble compounds

The ability of a water-soluble, single-stranded β-1,3/1,6-glucan (ssβ-glucan), recovered by hydrothermal treatment, to enhance the solubility and membrane permeability of poorly water-soluble compounds was examined. As a poorly water-soluble model compound, quercetin (QUE) was used. The aqueous solubility of spray-dried particles (SDPs) of QUE/ssβ-glucan was significantly enhanced compared with that of the untreated QUE powder and the physical mixture of QUE/ssβ-glucan. Fourier-transform infrared spectra and small-angle X-ray scattering suggested strong interactions between ssβ-glucan and QUE in the SDPs, which was attributable to QUE entrapment in the helical ssβ-glucan structure. The amount of QUE infused into Caco-2 cells from QUE/ssβ-glucan SDPs was 16-fold and 5-fold higher than the amount infused from untreated QUE powder and the physical mixture of QUE/ssβ-glucan, respectively. These results showed that water-soluble ssβ-glucan improved QUE dissolution and membrane permeability.

β-Glucan Improves Conditions of Chronic Fatigue in Mice by Stimulation of Immunity

Background:

Various natural molecules have been studied for the enhancement of physical endurance. Glucan has been found to improve various stress-related conditions and to improve fatigue and endurance.

Objective:

In our study, we focused on evaluation of glucan effects on some reactions involved in chronic fatigue.

Methods:

We measured phagocytosis of neutrophils, the production of IL-2, IL-4, and IL-10 by spleen cells, and levels of antioxidant glutathione and oxidative stress marker superoxide dismutase in brain. In addition, we measured the effects of glucan on water immersion and on rotarod.

Results:

The glucan supplementation strongly improved the suppressed phagocytosis and changes in cytokine and levels of oxidative stress markers caused by fatigue. In addition, glucan supplementation also increased the motor functioning of tested animals.

Conclusion:

Our data suggested that anti-fatigue properties of glucan are related with its well-established effects as stimulator of immune reactions.

Characterization of the secondary structure and order-disorder transition of a β-(1 → 3, 1 → 6)-glucan from Aureobasidium pullulans

This study revealed the secondary structures of the water-soluble Aureobasidium pullulans β-(1 → 3, 1 → 6)-d-glucan (APG) whose primary structural unit is a β-(1 → 3)-d-glucan backbone with four β-(1 → 6)-d-glucosyl branching units every six residues. Solid-state NMR spectroscopy, X-ray diffractometry (XRD), and small-angle X-ray scattering (SAXS) experiments involving samples prepared from lyophilized APG showed that APG forms a triple helix in H₂O and a random structure in DMSO. In addition, it was revealed that the transformation from the triple helix of APG to the random structure occurs reversibly, and that the triple helix is recovered from the random structure in DMSO/H₂O mixtures containing more than 30% H₂O. Solid-state NMR and diffraction studies revealed that the triple helix of APG is more stable than that of schizophyllan (SPG) whose structure comprises a β-(1 → 3)-d-glucan backbone with one β-(1 → 6)-d-branching unit every three residues. The APG helical pitch is 1.82 nm, which is about 10% longer than that of the triple helix of SPG. These findings show that the β-(1 → 6) side-chain frequency strongly affects the stability and helical pitch of a β-(1 → 3, 1 → 6)-d-glucan.

Anti-stress action of an orally-given combination of resveratrol, β-glucan, and vitamin C

Stress has repeatedly been found to reduce the abilities of the immune system to fight against individual attacks. The current dissatisfaction with classical medications has led to more attention being focused on natural molecules. As recent studies have suggested that some bioactive molecules can have synergistic effects in stimulation of immune system and reduction of stress, we have evaluated the stress-reducing effects of the resveratrol-β-glucan-vitamin C combination. We found that compared to its individual components, this combination was the strongest reducer of stress-related symptoms, including corticosterone levels and IL-6, IL-12 and IFN-γ production.

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.

Effect of polyphenols on production of steroid hormones from human adrenocortical NCI-H295R cells

Modulating steroid hormone levels is a curative and preventive measure for Cushing's syndrome, aldosteronism, and various stress-triggered symptoms. Polyphenols have been reported to inhibit steroidogenic enzymes such as 3β-hydroxysteroid dehydrogenase (3β-HSD) and aromatase. However, evidence for their inhibitory effects is fragmentary because it has been determined in studies with small groups of steroid hormones. To investigate the effects of steroids on complete steroidogenic pathways, comprehensive analysis of steroid hormones is necessary. Here we cultured forskolin-stimulated NCI-H295R, a human adrenocortical carcinoma cell line, in the presence of a polyphenol and employed GC-MS to simultaneously determine the levels of nine steroid hormones (pregnenolone, progesterone, deoxycorticosterone, aldosterone, 17α-hydroxyprogesterone, dehydroepiandrosterone, androstenedione, testosterone, and estradiol) in cell culture supernatant. We found that daidzein, genistein, apigenin, hesperetin, naringenin, and eriodictyol significantly reduced deoxycorticosterone and androstenedione levels (p<0.05), suggesting inhibition of 3β-HSD by these polyphenols. Apigenin was more potent than other polyphenols in increasing the levels of pregnenolone and 17α-hydroxyprogesterone, suggesting that it inhibits cytochrome P450 (CYP) 17 and CYP21, as well as 3β-HSD. Real-time reverse transcription polymerase chain reaction showed that apigenin significantly downregulated the expression levels of 3β-HSD, CYP17, and CYP21 mRNA (p<0.05). This is the first study to demonstrate the inhibitory effects of apigenin on CYP17 and CYP21.

Immune enhancing effects of WB365, a novel combination of Ashwagandha (Withania somnifera) and Maitake (Grifola frondosa) extracts

BACKGROUND

Stress has been found to significantly reduce the abilities of the immune system to fight infections. One of the ways to overcome the defects of the immune system is the strengthening of the defense reactions by nutrition.

AIMS

TO EVALUATE IMMUNE ENHANCING EFFECTS OF THE FOLLOWING MATERIAL: WB365, a novel combination of Ashwagandha (Withania somnifera) and Maitake (Grifola frondosa) extracts.

RESULTS

We found that both glucan-rich maitake extract and WB365 caused a similar stimulation of phagocytic activity. Stress-induced increase of corticosterone production was blocked by feeding with Ashwagandha extract and even more by WB365. Cytokine experiments showed that feeding with WB365 helped overcome the stress-related inhibition of IL-6, IL-12 and IFN-γ production.

CONCLUSION

This study clearly demonstrated that WB365, a combination of Maitake mushroom-derived glucan and Ashwagandha extracts, has strong pleiotropic biological effects related to immune health and stress reduction.

β-Glucan derived from Aureobasidium pullulans is effective for the prevention of influenza in mice

β-(1→3)-D-glucans with β-(1→6)-glycosidic linked branches produced by mushrooms, yeast and fungi are known to be an immune activation agent, and are used in anti-cancer drugs or health-promoting foods. In this report, we demonstrate that oral administration of Aureobasidium pullulans-cultured fluid (AP-CF) enriched with the β-(1→3),(1→6)-D-glucan exhibits efficacy to protect mice infected with a lethal titer of the A/Puerto Rico/8/34 (PR8; H1N1) strain of influenza virus. The survival rate of the mice significantly increased by AP-CF administration after sublethal infection of PR8 virus. The virus titer in the mouse lung homogenates was significantly decreased by AP-CF administration. No significant difference in the mRNA expression of inflammatory cytokines, and in the population of lymphocytes was observed in the lungs of mice administered with AP-CF. Interestingly, expression level for the mRNA of virus sensors, RIG-I (retinoic acid-inducible gene-I) and MDA5 (melanoma differentiation-associated protein 5) strongly increased at 5 hours after the stimulation of A. pullulans-produced purified β-(1→3),(1→6)-D-glucan (AP-BG) in murine macrophage-derived RAW264.7 cells. Furthermore, the replication of PR8 virus was significantly repressed by pre-treatment of AP-BG. These findings suggest the increased expression of virus sensors is effective for the prevention of influenza by the inhibition of viral replication with the administration of AP-CF.

Effects of β-(1,3-1,6)-D-glucan on irritable bowel syndrome-related colonic hypersensitivity

Irritable bowel syndrome (IBS) is a gastrointestinal disorder characterized by chronic abdominal pain associated with altered bowel habits. Since the prevalence of IBS is very high and thus, involves elevated health-care costs, treatment of this condition by methods other than prescribed medicines could be beneficial. β-(1,3)-D-glucan with β-(1,6) branches (β-glucan) has been used as a nutritional supplement for many years. In this study, we examined the effect of β-glucan on fecal pellet output and visceral pain response in animal models of IBS. Oral administration of β-glucan suppressed the restraint stress- or drug-induced fecal pellet output. β-Glucan also suppressed the visceral pain response to colorectal distension. These results suggest that β-glucan could be beneficial for the treatment and prevention of IBS.

A screening method for β-glucan hydrolase employing Trypan Blue-coupled β-glucan agar plate and β-glucan zymography

A new screening method for β-(1,3-1,6) glucan hydrolase was developed using a pure β-glucan from Aureobaisidum pullulans by zymography and an LB-agar plate. Paenibacillus sp. was screened as a producer a β-glucan hydrolase on the Trypan Blue-coupled β-glucan LB-agar plate and the activity of the enzyme was analyzed by SDS-β-glucan zymography. The β-glucan was not hydrolyzed by Bacillus spp. strains, which exhibit cellulolytic activity on CMC zymography. The gene, obtaining by shotgun cloning and encoding the β-glucan hydrolase of Paenibacillus sp. was sequenced.

Inhibitory effects of water-soluble low-molecular-weight β-(1,3-1,6) D-glucan isolated from Aureobasidium pullulans 1A1 strain black yeast on mast cell degranulation and passive cutaneous anaphylaxis

We investigated the effects of water-soluble low-molecular-weight β-(1,3-1,6) D-glucan isolated from Aureobasidium pullulans 1A1 strain black yeast (LMW-β-glucan) on mast cell-mediated anaphylactic reactions. Although it is known that LMW-β-glucan has anti-tumor, anti-metastatic and anti-stress effects, the roles of LMW-β-glucan in immediate-type allergic reactions have not been fully investigated. We examined whether LMW-β-glucan could inhibit mast cell degranulation and passive cutaneous anaphylaxis (PCA). LMW-β-glucan dose-dependently inhibited the degranulation of both rat basophilic leukemia (RBL-2H3) and cultured mast cells (CMCs) activated by calcium ionophore A23187 or IgE. However, LMW-β-glucan had no cytotoxicity towards RBL-2H3 cells and CMCs. Furthermore, orally administered LMW-β-glucan inhibited the IgE-induced PCA reaction in mice. These results show LMW-β-glucan to be a possible compound for the effective therapeutic treatment of allergic diseases.

Optimization of culture medium for enhanced production of exopolysaccharide from Aureobasidium pullulans

Polysaccharides produced by microorganisms are utilized for a variety of purposes, including the use in cosmetics and as food additives. More recently, polysaccharides have been exploited by the medical and pharmaceutical industries, and those originated from many species of mushrooms have been especially useful in industrial applications; however, the production and synthesis of these compounds is costly and time consuming. In this study, we developed a method for low-cost production of exopolysaccharide (EPS) that effectively screens components and optimizes medium composition using statistical methods (Plackett-Burman and Box-Behnken design). As a result, we obtained the following optimized medium: sucrose 165.73 g/L, sodium nitrate 3.08 g/L, dipotassium phosphate 1.00 g/L, potassium chloride 0.50 g/L, magnesium sulfate 0.50 g/L, ferrous sulfate 0.01 g/L, and 0.71 g/L of Ashbya gossypii extract. The maximum production of about 29 g/L EPS was achieved in the optimized medium during 84 h batch fermentation.

Protective effect of β-(1,3 → 1,6)-d-glucan against irritant-induced gastric lesions

β-(1,3)-d-Glucan with β-(1,6) branches has been reported to have various pharmacological activities, such as anti-tumour and anti-infection activities, which result from its immunomodulating effects. Gastric lesions result from an imbalance between aggressive and defensive factors. In the present study, we examined the effect of β-(1,3)-d-glucan with β-(1,6) branches isolated fromAureobasidium pullulanson the gastric ulcerogenic response in mice. Oral administration of β-glucan ameliorated gastric lesions induced by ethanol (EtOH) or HCl. This administration of β-glucan also suppressed EtOH-induced inflammatory responses, such as infiltration of neutrophils and expression of pro-inflammatory cytokines, chemokines and cell adhesion molecules (CAM) at the gastric mucosa. Of the various defensive factors, the levels of heat shock protein (HSP) 70 and mucin but not PGE2were increased by the administration of β-glucan. β-Glucan-dependent induction of the expression of HSP70 and mucin proteins and suppression of the expression of pro-inflammatory cytokines, chemokines and CAM were also observed in cultured cellsin vitro.The results of the present study suggest that β-glucan protects the gastric mucosa from the formation of irritant-induced lesions by increasing the levels of defensive factors, such as HSP70 and mucin.

Protective effects of water-soluble low-molecular-weight β-(1,3-1,6)D-glucan purified from Aureobasidium pullulans GM-NH-1A1 against UFT toxicity in mice

Objectives

5-Fluorouracil and its derivatives are widely used in the treatment of a variety of tumours. However, their use is associated with gastrointestinal toxicity, myelotoxicity and immune toxicity. In this study, we examined the protective effects of low-molecular-weight β-glucan isolated from Aureobasidium pullulans GM-NH-1A1 against toxicity of UFT (combination of tegafur (1-(2-tetrahydrofuryl)-5-fluorouracil) and uracil) in mice bearing colon 26 tumours.

Methods

UFT was administered orally at 50 mg/kg once daily for 14 days alone or with orally administered low-molecular-weight β-glucan, 25, 50 and 100 mg/kg twice daily.

Key findings

Tumour growth was inhibited equally in all treatment groups. Onset of diarrhoea, which started on day 9 of UFT administration, was delayed by concomitant administration of the β-glucan (50 and 100 mg/kg twice daily). Histological analysis showed that damage to small-intestine villi by UFT was inhibited by the orally administered β-glucan.

Conclusions

Oral administration of low-molecular-weight β-glucan prevents gastrointestinal mucositis associated with UFT therapy without interfering with its anti-tumour activity.

Structural characterisation and biological activities of a unique type beta-D-glucan obtained from Aureobasidium pullulans

A beta-D-glucan obtained from Aureobasidium pullulans (AP-FBG) exhibits various biological activities: it exhibits antitumour and antiosteoporotic effects and prevents food allergies. An unambiguous structural characterisation of AP-FBG is still awaited. The biological effects of beta-D-glucan are known to depend on its primary structures, conformation, and molecular weight. Here, we elucidate the primary structure of AP-FBG by NMR spectroscopy, and evaluate its biological activities. Its structure was shown to comprise a mixture of a 1-3-beta-D-glucan backbone with single 1-6-beta-D-glucopyranosyl side-branching units every two residues (major structure) and a 1-3-beta-D-glucan backbone with single 1-6-beta-D-glucopyranosyl side-branching units every three residues (minor structure). Furthermore, this beta-D-glucan exhibited immunostimulatory effects such as the accumulation of immune cells and priming effects against enterobacterium. To our knowledge, 1-3-beta-glucans like AP-FBG with such a high number of 1-6-beta-glucopyranosyl side branching have a unique structure; nevertheless, many 1-3-beta-glucans were isolated from various sources, e.g. fungi, bacteria, and plants.