Immune-modulating activities of glucans extracted from Pleurotus ostreatus and Pleurotus eryngii

Structural characterization of the glucan from Gastrodia elata Blume and its ameliorative effect on DSS-induced colitis in mice

The polysaccharide glucan was extracted from Gastrodia elata Blume, and its structural characterizations and beneficial effects against acute dextran sulfate sodium (DSS)-induced ulcerative colitis were investigated. The results showed that a polysaccharide GP with a molecular weight of 811.0 kDa was isolated from G. elata Blume. It had a backbone of α-D-1,4-linked glucan with branches of α-d-glucose linked to the C-6 position. GP exhibited protective effects against DSS-induced ulcerative colitis, and reflected in ameliorating weight loss and pathological damages in mice, increasing colon length, inhibiting the expression of inflammatory cytokines tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β), decreasing the levels of inflammatory related proteins NLRP3 and ASC, and elevating the anti-inflammatory cytokine interleukin-10 (IL-10) level in mouse colon tissues. GP supplementation also reinforced the intestinal barrier by promoting the expression of ZO-1, Occludin, and MUC2 of colon tissues, and positively regulated intestinal microbiota. Thus, GP treatment possessed a significant improvement in ulcerative colitis in mice, and it was expected to be developed as a functional food.

Antibacterial and hemostatic chitin sponge directly constructed from Pleurotus Eryngii via top-down approach

Chitin, the second most abundant polysaccharide on earth, possesses unique characteristics, including biosafety, biodegradability, and procoagulant activity, making it an attractive material for hemostasis. However, the conventional bottom-up construction of chitin-based materials is intricate and time-consuming. In this study, we have developed a top-down strategy to prepare a 3D porous chitin-based hemostatic sponge with exceptional hemostatic properties and antibacterial activity, directly from the spongy Pleurotus eryngii. The top-down method involves deproteinization, in situ quaternization, and tannin acid crosslinking. The obtained sponge has an interconnected microporous structure with high porosity (89.7 ± 3.2 %), endowing it with high water absorption (2047 ± 105 %) and rapid water-triggered shape-memory behavior (< 2 s). The sponge exhibits superior blood coagulant activity and outperforms standard medical gauze, gelatin sponge, and chitosan sponge in both topical artery and non-compressive liver puncture wound. In addition, the sponge exhibited significant antibacterial activity against both gram-positive Staphylococcus aureus and gram-negative Escherichia coli. In summary, this study provides a straightforward and practical approach for constructing an antibacterial and hemostatic chitin sponge that could be a valuable option for treating bleeding wounds.

β-Glucan extracts as high-value multifunctional ingredients for skin health: A review

β-Glucans, which are naturally present in cereals, yeast, and mushrooms, have gained attention as a potential natural source for functional foods and pharmaceuticals. Due to the availability of β-glucans from several sources, different extraction methods can be employed to obtain high purity extracts that can be further modified to enhance their solubility or other biological properties. Apart from their known ability to interact with the immune system, β-glucans possess specific properties that could benefit overall skin health and prevent age-related signs, including soothing and antioxidant activities. As a result, the use of β-glucans to mitigate damage caused by environmental stressors or skin-related issues that accelerate skin aging or trigger chronic inflammation may represent a promising, natural, eco-friendly, and cost-effective approach to maintaining skin homeostasis balance. This review outlines β-glucan extraction methodologies, molecular structure, functionalization approaches, and explores skin-related benefits of β-glucans, along with an overview of related products in the market.

Hypolipidemic mechanism of Pleurotus eryngii polysaccharides in high-fat diet-induced obese mice based on metabolomics

Objective

In this study, the structure of Pleurotus eryngii polysaccharides (PEPs) was characterized, and the mechanism of PEP on obesity and hyperlipidemia induced by high-fat diet was evaluated by metabonomic analysis.

Methods

The structure of PEPs were characterized by monosaccharide composition, Fourier transform infrared spectroscopy and thermogravimetry. In animal experiments, H&E staining was used to observe the morphological difference of epididymal adipose tissue of mice in each group. Ultrahigh performance liquid chromatography (UHPLC)-(QE) HFX -mass spectrometry (MS) was used to analyze the difference of metabolites in serum of mice in each group and the related metabolic pathways.

Results

The PEPs contained nine monosaccharides: 1.05% fucose, 0.30% arabinose, 17.94% galactose, 53.49% glucose, 1.24% xylose, 23.32% mannose, 1.30% ribose, 0.21%galacturonic acid, and 1.17% glucuronic acid. The PEPs began to degrade at 251°C (T0), while the maximum thermal degradation rate temperature (Tm) appeared at 300°C. The results histopathological observation demonstrated that the PEPs had signifificant hypolipidemic activities. After PEPs intervention, the metabolic profile of mice changed significantly. A total of 29 different metabolites were selected as adjunctive therapy to PEPs, for treatment of obesity and hyperlipidemia-related complications caused by a high-fat diet. These metabolites include amino acids, unsaturated fatty acids, choline, glycerol phospholipids, and other endogenous compounds, which can prevent and treat obesity and hyperlipidemia caused by a high-fat diet by regulating amino acid metabolism, fatty acid metabolism, and changes in metabolic pathways such as that involved in the citric cycle (TCA cycle).

Conclusions

The presented results indicate that PEPs treatment can alleviate the obesity and hyperlipidemia caused by a high-fat diet and, thus, may be used as a functional food adjuvant, providing a theoretical basis and technical guidance for the prevention and treatment of high-fat diet-induced obesity and hyperlipidemia.

Identification of s9ap used as an endogenous reference gene in qualitative and real-time quantitative PCR detection of Pleurotus eryngii

BACKGROUND

Pleurotus eryngii is a kind of edible fungi with good quality, and it is popular among consumers. At present, some adulterated edible fungi are available in the market. The rights and interests of consumers can be ensured by establishing a practical edible fungi detection system. Among the existing methods for detecting food adulteration, endogenous reference gene amplification is convenient and reliable. However, no ideal endogenous reference gene is available for P. eryngii.

METHODS AND RESULTS

In this study, s9ap was screened as an endogenous reference gene through sequence alignment. Qualitative and quantitative PCR analysis of this gene was carried out in one P. eryngii variety and 18 other species. The detection limit of quantitative PCR was 400 pg, and no s9ap amplification products were detected in the 18 other species.

CONCLUSIONS

This study confirmed that s9ap was an ideal endogenous reference gene for the detection of P. eryngii. This method was also suitable for processed food products.

Potential Use of Cardunculus Biomass on Pleurotus eryngii Production: Heteroglycans Content and Nutritional Properties (Preliminary Results)

The new perspective of using waste biomass to cultivate mushrooms as a source of protein for human nutrition, in line with the circular economy principles, is receiving increasing attention in the scientific community and represents great wealth in terms of environmental sustainability. Pleurotus eryngii is a mushroom also known as cardunculus mushroom due to its ability to grow on this plant. This study explores the potential intrinsic properties of cardunculus (for example, the presence of inulin in the roots) as raw material for the growth of cardunculus mushrooms, and the influence on heteroglycan content and nutrition parameters of the fruiting bodies. Both mycelium and fruiting bodies were used to determine the heteroglycan content in the presence of inulin or cardunculus roots rich in inulin. To produce heteroglycans from P. eryngii in greater quantities and shorter times without having to wait for the formation of the fruiting bodies, the mycelium could be used. The results showed that the presence of cardunculus biomass positively influences the heteroglycan content of P. eryngii. In terms of nutritional parameters, higher contents of polyphenols, flavonoids, anthocyanins, and antioxidant activity were detected in P. eryngii grown on the cardunculus stem and root substrate. In conclusion, recycling cardunculus biomass to generate growth blocks for edible mushrooms is a winning choice due to the opportunity to use this biomass waste, which is gaining more and more attention due to the increase in cultivated areas and the use of fruiting bodies of P. eryngii as a functional food and source of molecules with potential biological activities.

Extraction and immunomodulatory activity of the polysaccharide obtained from Craterellus cornucopioides

In this study, we investigated the structural features of the polysaccharide obtained from Craterellus cornucopioides (CCP2) by high-performance liquid chromatography, Fourier transform infrared spectroscopy and ion chromatography. The results showed that CCP2 was a catenarian pyranose that principally comprised of mannose, galactose, glucose, and xylose in the ratio of 1.86: 1.57: 1.00: 1.14, with a molecular weight of 8.28 × 10⁴ Da. Moreover, the immunoregulation effect of CCP2 was evaluated both in vitro and in vivo. It displayed a remarkable immunological activity and activation in RAW264.7 cells by enhancing the phagocytosis of macrophages in a dose-dependent manner without showing cytotoxicity at the concentrations of 10–200 μg/mL in vitro. Additionally, Histopathological analysis indicated the protective function of CCP2 against immunosuppression induced by cyclophosphamide (Cy). Meanwhile, the intake of CCP2 had better immunoregulatory activity for immunosuppression BALB/c mice model. After prevention by CCP2, the spleen and thymus weight indexes of BALB/c mice model were significantly increased. The RT-qPCR and Western Blot results provided comprehensive evidence that the CCP2 could activate macrophages by enhancing the production of cytokines (IL-2, IL-6, and IL-8) and upregulating the protein expression of cell membrane receptor TLR4 and its downstream protein kinase (TRAF6, TRIF, and NF-κB p65) production of immunosuppressive mice through TLR4-NFκB p65 pathway. The results demonstrated that CCP2 could be a potential prebiotic and might provide meaningful information for further research on the immune mechanism.

Functional Characterization and Structural Basis of the β-1,3-Glucan Synthase CMGLS from Mushroom Cordyceps militaris

β-1,3-Glucan synthases play key roles in glucan synthesis, cell wall assembly, and growth of fungi. However, their multi-transmembrane domains (over 14 TMHs) and large molecular masses (over 100 kDa) significantly hamper understanding of their catalytic characteristics and mechanisms. In the present study, the 5841-bp gene CMGLS encoding the 221.7 kDa membrane-bound β-1,3-glucan synthase CMGLS in Cordyceps militaris was cloned, identified, and structurally analyzed. CMGLS was partially purified with a specific activity of 87.72 pmol/min/μg, a purification fold of 121, and a yield of 10.16% using a product-entrapment purification method. CMGLS showed a strict specificity to UDP-glucose with a K_m value of 84.28 μM at pH 7.0 and synthesized β-1,3-glucan with a maximum degree of polymerization (DP) of 70. With the assistance of AlphaFold and molecular docking, the 3D structure of CMGLS and its binding features with substrate UDP-glucose were proposed for the first time to our knowledge. UDP-glucose potentially bound to at least 11 residues via hydrogen bonds, π-stacking ,and salt bridges, and Arg 1436 was predicted as a key residue directly interacting with the moieties of glucose, phosphate, and the ribose ring on UDP-glucose. These findings would open an avenue to recognize and understand the glucan synthesis process and catalytic mechanism of β-1,3-glucan synthases in mushrooms.

β-Glucans from Yeast—Immunomodulators from Novel Waste Resources

β-glucans are a large class of complex polysaccharides with bioactive properties, including immune modulation. Natural sources of these compounds include yeast, oats, barley, mushrooms, and algae. Yeast is abundant in various processes, including fermentation, and they are often discarded as waste products. The production of biomolecules from waste resources is a growing trend worldwide with novel waste resources being constantly identified. Yeast-derived β-glucans may assist the host’s defence against infections by influencing neutrophil and macrophage inflammatory and antibacterial activities. β-glucans were long regarded as an essential anti-cancer therapy and were licensed in Japan as immune-adjuvant therapy for cancer in 1980 and new mechanisms of action of these molecules are constantly emerging. This paper outlines yeast β-glucans’ immune-modulatory and anti-cancer effects, production and extraction, and their availability in waste streams.

Influence of ultrasonic pretreatments on microwave hot-air flow rolling drying mechanism, thermal characteristics and rehydration dynamics of Pleurotus eryngii

BACKGROUND

In order to improve the drying efficiency and reduce the drying energy consumption of Pleurotus eryngii, microwave hot-air flow rolling drying (MHARD) coupled with ultrasonic pretreating time (0, 20, 40, and 60 min) was used to investigate the drying profile, thermal characteristics, water migration, microstructure and rehydration dynamics of P. eryngii using differential scanning calorimetry (DSC), low-field nuclear magnetic resonance (LF-NMR) analysis and scanning electron microscopy (SEM).

RESULTS

Results showed that the drying time of P. eryngii was 80, 70, 60 and 50 min, accordingly. Energy consumption was significantly reduced by ultrasonic pretreatment, and moisture effective diffusivity (D_eff ) was increased with the increase of ultrasonic pretreating time. DSC curves showed that the drying process was accelerated by ultrasonic pretreatment significantly by enhancing the heat transfer. Meanwhile, SEM images showed that the cell was broken and numbers of irregular holes appeared in the ultrasound-pretreated samples. In terms of rehydration dynamics, Page model could well model the rehydration kinetics of dried P. eryngii with R²  > 0.99.

CONCLUSION

The findings indicate that ultrasonic pretreatment is a promising method for MHARD of P. eryngii as it can enhance the drying process, and show potential for industrial application. © 2021 Society of Chemical Industry.

Delivery of Phenolic Compounds, Peptides and β-Glucan to the Gastrointestinal Tract by Incorporating Dietary Fibre-Rich Mushrooms into Sorghum Biscuits

Sorghum biscuits were enriched with mushroom powders (Lentinula edodes, Auricularia auricula and Tremella fuciformis) at 5%, 10% and 15% substitution levels. An in vitro gastrointestinal digestion was used to evaluate the effect of this enrichment on the phenolic content and soluble peptide content as well as antioxidant activities of the gastric or intestinal supernatants (bio-accessible fractions), and the remaining portions of phenolic compounds, antioxidants and β-glucan in the undigested residue (non-digestible fraction). The phenolic content of the gastric and intestinal supernatants obtained from digested mushroom-enriched biscuits was found to be higher than that of control biscuit, and the phenolic content was positively correlated to the antioxidant activities in each fraction (p < 0.001). L. edodes and T. fuciformis enrichment increased the soluble protein content (small peptide) of sorghum biscuits after in vitro digestion. All mushroom enrichment increased the total phenolic content and β-glucan content of the undigested residue and they were positively correlated (p < 0.001). The insoluble dietary fibre of biscuits was positively correlated with β-glucan content (p < 0.001) of undigested residue. These findings suggested that enriching food with mushroom derived dietary fibre increases the bioavailability of the non-digestible β-glucan and phenolic compounds.

Inhibitory effects of β-type glycosidic polysaccharide from Pleurotus eryngii on dextran sodium sulfate-induced colitis in mice

The aim of the present study was to determine the inhibitory effects and the potential underlying mechanisms of a novel Pleurotus eryngii β-type glycosidic polysaccharide (WPEP) on colitis. To achieve this, sixty CD-1 (ICR) mice were divided into six groups including healthy and colitic mice treated with or without WPEP at two different doses (n = 10). The results showed that WPEP displayed a significant inhibitory effect on colitis as indicated by the lowered disease activity index in the treated colitic mice compared to the untreated colitic mice (2.78 ± 0.50 to 1.80 ± 0.17). A decrease in pro-inflammatory cytokine concentrations and pro-inflammatory protein expressions and an increase in the colon length (9.31 ± 0.59 cm to 10.89 ± 1.20 cm) along with histological improvements were also observed in the treated colitic mice compared to the untreated colitic mice in the present study. Flow cytometry and western blotting analysis revealed that these anti-colitis effects were associated with decreased accumulation of CD45+ immune cells, CD45 + F4/80+ macrophages and CD45 + Gr1+ neutrophils. Moreover, the 16s rRNA sequencing analysis of the gut microbiota revealed that WPEP partially reversed gut microbiota dysbiosis in the colitic mice including the decreased abundance of Akkermansia muciniphila (35.80 ± 9.10% to 18.24 ± 6.23%) and Clostridium cocleatum (2.34 ± 1.78% to 0.011 ± 0.003%) and the increased abundance of Bifidobacterium pseudolongum (3.48 ± 2.72% to 9.65 ± 3.74%), Lactobacillus reuteri (0.007 ± 0.002% to 0.21 ± 0.12%), Lactobacillus salivarius (1.23 ± 0.87% to 2.22 ± 1.53%) and Ruminococcus bromii (0.009 ± 0.001% to 3.83 ± 1.98%). In summary, our results demonstrated that WPEP could be utilized as a functional food component in colitis management as well as a potential prebiotic agent to improve inflammation-related disorders.

Water-soluble polysaccharides from Pleurotus eryngii fruiting bodies, their activity and affinity for Toll-like receptor 2 and dectin-1

The mushroom cell wall contains polysaccharides that can activate cells of the innate immune system through receptors such as Toll-like receptors (TLR) and dectin-1. In the present study, Pleurotus eryngii polysaccharide fractions containing a 3-O methylated mannogalactan and (1→3)/(1→6)-β-d-glucans were isolated and extensively characterized by 2D NMR and methylation analysis. Traces of a (1→3)-α-d-glucan and a (1→2)-α-d-mannan were also observed. Affinity for TLR2, TLR2-TLR6 and dectin-1 using HEK-cells expressing the relevant receptor genes was tested. PeWN, containing the 3-O methylated mannogalactan, was inactive towards TLR2, whereas fraction PeWB, containing more β-glucan, activated the TLR2-TLR6 heterodimer. Activation of the human β-glucan receptor dectin-1 correlated with the amount of β-glucan in each fraction. Nitric oxide and cytokine supernatant levels of D2SC/1 dendritic cells stimulated with the P. eryngii fractions and interferon-γ were low to moderate. The results indicate that the immunomodulatory activity of water-soluble P. eryngii polysaccharide fractions is modest.

Biologically active polysaccharide from edible mushrooms: A review

Mushrooms are renewable natural gift for humankind, furnished with unique taste, flavor and medicinal properties. For the last few decades study of mushroom polysaccharides has become a matter of great interest to the researchers for their immunomodulating, antimicrobial, antioxidant, anticancer, and antitumor properties. Molecular mass, branching configuration, conformation of polysaccharides and chemical modification are the major factors influencing their biological activities. The mechanism of action of mushroom polysaccharides is to stimulate T-cells, B-cells, natural killer cells, and macrophage dependent immune responses via binding to receptors like the toll-like receptor-2, dectin-1. The present review offers summarized and significant information about the structural and biological properties of mushroom polysaccharides, and their potential for development of therapeutic materials.

Differences in anti-inflammatory properties of water soluble and insoluble bioactive polysaccharides in lipopolysaccharide-stimulated RAW264.7 macrophages

β-Linked polysaccharides including β-glucans are well known to be important functional ingredients, and are known to possess immunomodulatory and anti-tumor activities. This study aimed to investigate the anti-inflammatory properties and participating receptor of water soluble and insoluble bioactive polysaccharides from Grifola frondosa (GFP, non-digestible water soluble polysaccharides), Laminaria digitata (laminarin, a water soluble β-glucan) and Saccharomyces cerevisiae (zymosan, a water insoluble β-glucan) in lipopolysaccharide (LPS)-stimulated parental and Dectin-1 highly expressing RAW264.7 macrophages. Results showed that GFP and laminarin significantly inhibited nitric oxide and prostaglandin E2 production, but only the GFP with high molecular weight exhibited strong inhibition on pro-inflammatory cytokine (TNF-α and IL-6) secretion in a concentration-dependent manner. The activation of NF-κB was also significantly down-regulated by GFP treatment as compared with cells treated with LPS alone. Although GFP and laminarin were able to bind to β-glucan receptor Dectin-1, there was no relationship between the inhibitory potency and the content of β-glucans in GFP, and these inhibitory effects were not affected by the expression level of Dectin-1 in macrophage cells. In contrast, zymosan significantly intensified LPS-induced inflammatory responses through Dectin-1. In conclusion, these results suggest that the inhibitory effects of water soluble polysaccharides on LPS-induced pro-inflammatory mediator production in murine macrophages may not involve β-glucan receptor Dectin-1.

Selenium and Zinc Biofortification of Pleurotus eryngii Mycelium and Fruiting Bodies as a Tool for Controlling Their Biological Activity

Pleurotus eryngii (DC:Fr.) Quel. is a cultivated mushroom of high culinary value and medicinal properties. Mycelium of P. eryngii is characterized by the ability of effective bio-elements absorption from growth media so it could be biofortified with trace elements with a functional activity in the human body. In this study, the ability of P. eryngii mycelia from in vitro cultures as well as fruiting bodies were investigated in terms of their effectiveness in zinc and selenium accumulation. The effect of Se and Zn biofortification on productivity, chemical compounds, and bio-elements content of P. eryngii was determined as well. To enhance Se and Zn content in P. eryngii fruiting bodies and mycelia, substrates were supplemented with sodium selenite, at a concentration of 50 mg L^-1, zinc sulfate, and zinc hydro-aspartate at a concentration of 87.2 and 100.0 mg L^-1, respectively. Mentioned Zn concentrations contained the same amount of zinc(II) ions, namely 20 mg L^-1. The content of organic compounds include phenolic compounds and lovastatin, which were determined by a high-performance liquid chromatography with diode-array detector (HPLC-DAD) and reverse phase high-performance liquid chromatography (RP-HPLC) method with UV detection. The ability of P. eryngii to accumulate zinc and selenium from the culture medium was demonstrated. The degree of accumulation of zinc turned out to be different depending on the type of salt used. The present study also showed that conducting mycelium of P. eryngii in in vitro culture, with a higher content of zinc ions, can result in obtaining the materials with better antioxidant ability. The results of this study can be used to develop the composition of growing media, which ensures the production of biomass with the desired composition of elements.

Polysaccharides of mushroom Pleurotus spp.: New extraction techniques, biological activities and development of new technologies

The biodiversity of mushrooms Pleurotus spp. is impressive due to its complexity and diversity related to the composition of chemical structures such as polysaccharides, glycoproteins and secondary metabolites such as alkaloids, flavonoids and betalains. Recent studies of polysaccharides and their structural elucidation have helped to direct research and development of technologies related to pharmacological action, production of bioactive foods and application of new, more sophisticated extraction tools. The diversity of bioactivities related to these biopolymers, their mechanisms and routes of action are constant focus of researches. The elucidation of bioactivities has helped to formulate new vaccines and targeted drugs. In this context, in terms of polysaccharides and the diversity of mushrooms Pleurotus spp., this review seeks to revisit the genus, making an updated approach on the recent discoveries of polysaccharides, new extraction techniques and bioactivities, emphasising on their mechanisms and routes in order to update the reader on the recent technologies related to these polymers.

Polysaccharide-Rich Fractions from Rosa rugosa Thunb.-Composition and Chemopreventive Potential

The huge health-beneficial potential of polysaccharides encourages the search for novel sources and applications of these compounds. One poorly explored source of polysaccharides is the rose. The content and biological activity of polysaccharides in rose organs is an almost completely unaddressed topic, therefore, polysaccharide-rich extracts (crude polysaccharides, CPLs) from petals, leaves, hips, and achenes of Rosa rugosa Thunb. were studied for their composition and the influence on various cellular processes involved in the development of cancer and other civilization diseases. The study revealed the presence of water-soluble and -insoluble polysaccharides (including β-glucans) and protein-polysaccharide conjugates in rose organs. Rose hips were found to be the most abundant source of polysaccharides. Different polysaccharide-rich extracts showed the ability to inhibit pro-inflammatory enzymes (COX-1, COX-2, hyaluronidase), a radical scavenging effect (against DPPH^• and ABTS^•+), and antiproliferative activity (in the A549 lung and SW480 colon cancer cell lines) in in vitro assays. Therefore, rose crude polysaccharides are very promising and can potentially be used as natural chemopreventive agents.

Beta Glucan: Supplement or Drug? From Laboratory to Clinical Trials

Glucans are part of a group of biologically active natural molecules and are steadily gaining strong attention not only as an important food supplement, but also as an immunostimulant and potential drug. This paper represents an up-to-date review of glucans (β-1,3-glucans) and their role in various immune reactions and the treatment of cancer. With more than 80 clinical trials evaluating their biological effects, the question is not if glucans will move from food supplement to widely accepted drug, but how soon.