Structural diversity of fungal glucans

Advanced insights into mushroom polysaccharides: Extraction methods, structure-activity, prebiotic properties, and health-promoting effects

Mushroom-derived polysaccharides, especially β-glucans, have attracted considerable attention because of their various biological regulatory functions. Advanced extraction technologies, including ultrasonic-assisted, microwave-assisted, enzyme-assisted, ultrasonic-microwave synergistic, subcritical water, and aqueous two-phase extractions, are extensively utilized to optimize the efficient recovery of biologically active compounds from mushrooms, progressively supplanting conventional methods. In addition, mushroom polysaccharides are acknowledged as "important biological response modifiers." Beyond their diverse bioactivities, including anticancer, immunomodulatory, anti-inflammatory, antimicrobial, antiviral, antidiabetic, hypocholesterolemia, anti-lipidemic, and antioxidant effects, increasing interest has been directed towards their prebiotic potential, especially regarding their ability to influence gut microbiota. This review presents a comprehensive summary of the extraction and purification methods, biological properties, structure-function relationships, and mechanisms of mushroom polysaccharides, highlighting the latest advancements in the field from 2019 to 2024. Additionally, this review discusses the key findings and limitations associated with the structure-function correlation. While most studies focus on β-glucans or their extracts, α-glucans and chitin have gained increasing attention. The prebiotic potential is associated with α-glucans and chitin, with chitin recognized for its substantial antimicrobial and wound-healing properties. This review systematically identifies current research gaps and proposes avenues for future investigation into the therapeutic potential of mushroom polysaccharides. However, further research is required to comprehensively understand their full therapeutic potential.

A Novel Polysaccharide Purified from Tricholoma matsutake: Structural Characterization and In Vitro Immunological Activity

Tricholoma matsutake, as a rare wild edible mushroom, is popular due to its unique flavor and taste, as well as high nutritional and economic value. Investigating the relationship between the complex structure and in vitro immunological activity of TMP-2a, a novel polysaccharide isolated from T. matsutake, was the aim of this study. The results showed that TMP-2a consisted of six monosaccharides, fucose, glucosamine hydrochloride, galactose, glucose, mannose, and glucuronic acid, with molar ratios of 8.8:0.6:23.4:48.1:15.1:4.0 and a molecular weight of 27,749 Da. Furthermore, TMP-2a was mainly composed of →6)-β-Glcp-(1→ with →3)-β-D-Glcp-(1→ forming the main chain, with a small amount of →2,6)-α-D-Manp-(1→ and →6)-α-D-Galp-(1→ structural units attached, and the branched chain was mainly composed of β-Glcp-(1→ or a small amount of α-L-Fucp-(1→ as a telosaccharide attached at the O-6 position of →3,6)-β-D-Glcp-(1→. TMP-2a enhanced the proliferation and phagocytic activity of mouse macrophage RAW264.7, as well as the secretion of NO and cytokines (TNF-α, IL-6, IL-1β) to a considerable degree, maybe attributable to its glucan structure and the elevated presence of (1→3)-β-D-Glcp glycosidic bonds. This study establishes a basis for the structural identification and comprehensive investigation of the functional activities of T. matsutake polysaccharides while also offering a theoretical framework for the creation of T. matsutake-related food products.

Application prospect of polysaccharide in the development of vaccine adjuvants

Vaccination is an effective strategy for preventing infectious diseases. Subunit vaccines offer more precise targeting and safer protection compared with traditional inactivated virus vaccines. However, due to their poor immunogenicity, subunit vaccines necessitate the use of adjuvants to stimulate the immune system. Adjuvants have long been incorporated into vaccines to enhance the body's immune response, allowing for reduced dosage and lower production costs. Despite the development of numerous vaccine adjuvants, few exhibit the necessary potency and low toxicity for clinical use, often due to limited efficacy or adverse side effects. This underscores the urgent need for novel human vaccine adjuvants that are safe, effective, and cost-efficient. Recent studies have identified certain natural polysaccharides as promising human vaccine adjuvants due to their immunostimulatory properties, low toxicity, and high safety profiles, which enhance both humoral and cellular immunity. These natural polysaccharides are primarily derived from traditional Chinese medicine (TCM) plants, bacteria, and yeast. This review comprehensively analyzes several promising polysaccharide adjuvants, discussing their clinical applications, market potential, and immunoregulatory activities. In summary, the future prospects of polysaccharides provide valuable insights for the application and development of vaccine adjuvants.

Structure and strain specificity for polysaccharides from king oyster mushroom (Pleurotus eryngii) fruiting bodies

King oyster mushroom Pleurotus eryngii is cultivated worldwide for culinary and to improve human health. However, the potential of some Mediterranean representatives of this species is still not evaluated. This work focuses on the study of polysaccharides from fruiting bodies of two Tunisian strains, P. eryngii var. elaeoselini and P. eryngii var. ferulae, and, for comparison, one deposited P. eryngii originated from Korea. Polysaccharides were successively extracted with hot water using microwave heating and 1 mol L-1 aqueous sodium hydroxide. The crude hot water extracts were purified by treating them with proteolytic enzymes, and the alkaline extracts were purified by re-dissolving with dimethyl sulphoxide. In both cases, a decrease or removal of proteins was detected. Glucans predominated in all these products; the insoluble parts also contained chitin. The purified hot water extracts contained glycogen, β-d-glucans and mannogalactan. Branching (1 → 3)(1 → 6)-β-d-glucan was the major polysaccharide in the alkali-soluble fractions, while (1 → 3)-α-d-glucan was only a minor component. The Tunisian strains demonstrated a higher proportion of water-soluble polysaccharides, compared to the alkaline soluble ones, and more β-d-glucan in the insoluble chitin-glucan complexes. Fruiting body proteins of these strains are more available for solubilisation and enzymatic or alkaline degradation and, thus, may have higher nutritional value than those of the reference strain. As a source of proteins or polysaccharides, the Tunisian endemic P. eryngii strains of this study are promising for the domestication and cultivation of fruiting bodies for gastronomic purposes in the North African region.

Chemical structure characterization of polysaccharides using diffusion ordered NMR spectroscopy (DOSY)

The potential of DOSY NMR spectroscopy to distinguish the linkage pattern of chemically related polysaccharides was evaluated using β-glucans isolated from yeast (Saccharomyces cerevisiae) and mushroom (Pleurotus eryngii). Laminarin from Laminaria digitata was included for chemical shift comparison. Characterization through methylation and 1D/2D NMR analysis showed that all the samples were constituted by →3)-Glcp-(1→; →3,6)-Glcp-(1→; Glcp-(1→ and →6)-Glcp-(1→ linkages. The results obtained allowed the identification of the well-known chemical structure of laminarin. Moreover, DOSY demonstrated that the units →3)-Glcp-(1→ and →6)-Glcp-(1→ from yeast β-glucans, presented the same diffusion time. For the mushrooms β-glucans, the diffusion time of these units were different, confirming that they belong to distinct polysaccharides. The yeast and the mushroom polysaccharide samples presented the same NMR correlations, but after DOSY analysis, different structures could be proposed. Therefore, DOSY NMR spectroscopy could be a tool for the identification of different linkage patterns of polysaccharides belonging to the same group and may be a useful contribution to the chemical structure and biological activity correlation studies of such structures.

Structure-activity relationship of synthesized glucans from Ganoderma lucidum with in vitro hypoglycemic activity

The synthetic polysaccharides, which have precise structure, can be used to design new drugs by comparing structure-activity relationships (SAR). Improved protein stability may be due to the interaction between the polysaccharides and protein, which includes covalent and noncovalent interactions. It is critical to investigate the SAR of polysaccharides with a precise structure from the perspective of protein stability. Glucans-insulin interaction may be a useful stratagy to solve this problem. This study reports the SAR of the synthesized glucan GLSWA-1 and its substructures 2-4 on insulin secretion and discusses its mechanism. The results showed that although GLSWA-1 and its substructures 2-4 bind insulin to varying degrees, compound 2 improves insulin secretion in a dose-dependent manner. Further research found that compound 2 maintains the thermal stability of insulin better than GLSWA-1 through stronger hydrogen bonding, and molecular dynamics simulations demonstrated that compound 2 can form a "groove-binding model" with insulin. This study considerably improves the research on the SAR of glucan based on insulin thermostability and indicates that compound 2, its linear structure, appropriate chain flexibility ((1 → 6)-glucoside bonds), low molecular weight, and smaller steric hindrance is a potential hypoglycemic agent.

Preparation methods, structural features, biological activities and potential applications of Ophiopogon japonicus polysaccharides: An updated review

Ophiopogon japonicus (O. japonicus) has a history of thousands of years as herbal medicine and nutritional food in China. Polysaccharides are one of the main bioactive components of O. japonicus. Various extraction methods and purification techniques have been employed to obtain O. japonicus polysaccharides (OJPs). Nevertheless, the structural characteristics of OJPs remain incompletely understood and require further investigation through the integration of advanced analytical techniques to uncover potential structure-activity relationships. Moreover, OJPs exhibit a variety of biological activities, such as regulating gut microbiota, providing cardiovascular protection, lowering blood glucose, and combating obesity. These diverse pharmacological effects make OJPs highly promising for widespread application in industries such as pharmaceuticals and food. Therefore, this review aims to provide a comprehensive overview of OJPs, covering their preparation methods, structural features, bioactivity, and structure-activity relationships. Here also emphasizes the significant promise of medicine and functional foods fields and advocating for their integration into clinical and industrial processes.

Edible Mushrooms: a Nutrient-Rich Ingredient for Healthier Food Products - A Review

OBJECTIVE OF THE REVIEW

Edible mushrooms are found to be foods with high nutritional content, which have been shown to be more widely used ingredients in cooking in traditional dishes. This article explores the rising trend in the use of edible mushrooms in new formulations of functional foods, taking advantage of their properties and benefits in human health.

RECENT FINDINGS

The use of mushrooms as an ingredient in new or modified food formulations is driven by solid evidence of their nutritional content and bioactivity. Mushrooms stand out for their high biological value and high bioavailability protein content, as well as dietary fiber that promotes improved digestive health. Other micronutrients present are B vitamins and minerals such as selenium, phosphorus and potassium. Mushroom flour has been the prevalent mode of addition to food formulations. This type of format aims to preserve and concentrate the nutritional content of mushrooms and has achieved nutritional enrichment of products. The use of this food has also been explored to improve technological qualities in food development, so it is intended to position itself as a natural additive. This review synthesizes data on the nutritional composition, bioactive properties, and physicochemical attributes of mushrooms, emphasizing their multifaceted contributions to modern food formulations. It advocates for further research to optimize mushroom application in diverse food products and to address practical challenges for seamless integration.

Characterization of Carbohydrate Specificity of Monoclonal Antibodies to Fungal Antigenic Markers Using Biotinylated Oligosaccharides as Coating Antigens

Mannan and β-(1→3)-glucan are two polysaccharide markers that are characteristic for a number of fungal pathogens, including Candida albicans, which is the most common cause of invasive mycoses in humans. In this study, we examined epitope specificity of two monoclonal antibodies, CM532 and FG70, which recognize certain oligosaccharide fragments of these fungal polysaccharides. Using a panel of biotinylated oligosaccharides as coating antigens, we found that the CM532 antibody obtained by immunization with the pentamannoside β-Man-(1→2)-β-Man-(1→2)-α-Man-(1→2)-α-Man-(1→2)-α-Man KLH conjugate, selectively recognizes the trisaccharide β-Man-(1→2)-α-Man-(1→2)-α-Man epitope. Another antibody, FG70, obtained by immunization with heptaglucan β-Glc-(1→3)-[β-Glc-(1→3)]5-β-Glc conjugate with KLH, interacts with the linear β-(1→3)-linked pentaglucoside fragment, and presence of 3,6-branches within this epitope does not significantly affect the interaction efficiency. The data obtained indicate that the monoclonal antibodies under consideration could be used to create effective diagnostics for detection of fungal infections, which are not available at present.

Progress and prospect of polysaccharides as adjuvants in vaccine development

Vaccines are an effective approach to confer immunity against infectious diseases. Modern subunit vaccines offer more precise target and safe protection compared to traditional whole-pathogen vaccines. However, subunit vaccines require adjuvants to stimulate the immune system due to the less immunogenicity. Adjuvants strengthen immunogenicity by enhancing, modulating, and prolonging the immune response. Unfortunately, few adjuvants have sufficient potency and low enough toxicity for clinical use, highlighting the urgent need for new vaccine adjuvants with the characteristics of safety, efficacy, and cost-effectiveness. Notably, some natural polysaccharides have been approved as adjuvants in human vaccines, owing to their intrinsic immunomodulation, low toxicity, and high safety. Natural polysaccharides are mainly derived from plants, bacteria, and yeast. Partly owing to the difficulty of obtaining them, synthetic polysaccharides emerged in clinical trials. The immune mechanisms of both natural and synthetic polysaccharides remain incompletely understood, hindering the rational development of polysaccharide adjuvants. This comprehensive review primarily focused on several promising polysaccharide adjuvants, discussing their recent applications in vaccines and highlighting their immune-modulatory effects. Furthermore, the future perspectives of polysaccharides offer insightful guidance to adjuvant development and application.

Anti-Cancer Potential of Linear β-(1→6)-D-Glucan from Agaricus bisporus on Estrogen Receptor-Positive (ER+) Breast Cancer Cells

Mushroom β-D-glucans can be isolated from several species, including the widely consumed Agaricus bisporus. Besides immunomodulatory responses, some β-D-glucans may exhibit direct antitumoral effects. It was previously observed that a β-(1→6)-D-glucan (BDG16) has indirect cytotoxicity on triple-negative breast cancer cells. In this study, the cytotoxicity of this same glucan was observed on estrogen receptor-positive (ER+) breast cancer cells (MCF-7). Cell viability was determined by multiple methods to assess metabolic activity, lysosomal membrane integrity, and adhesion capacity. Assays to evaluate cell respiration, cell cycle, apoptosis, necroptosis, and oxidative stress were performed to determine the action of BDG16 on MCF-7 cells. A gradual and significant cell viability reduction was observed when the cells were treated with BDG16 (10-1000 µg/mL). This result could be associated with the inhibition of the basal state respiration after incubation with the β-D-glucan. The cells showed a significant arrest in G1 phase population at 1000 µg/mL, with no induction of apoptosis. However, an increase in necrosis and necroptosis at the same concentration was observed. No difference in oxidative stress-related molecules was observed. Altogether, our findings demonstrate that BDG16 directly induces toxicity in MCF-7 cells, primarily by impairing mitochondrial respiration and promoting necroptosis. The specific mechanisms that mediate this action are being investigated.

A Ligand-Controlled Approach Enabling Gold(I)-Catalyzed Stereoinvertive Glycosylation with Primal Glycosyl ortho-Alkynylbenzoate Donors

A diarylurea-containing phosphine ligand-modulated stereoinvertive O-glycosylation with primal furanosyl and pyranosyl ortho-alkynylbenzoate (ABz) donors under gold(I) catalysis is disclosed. Both α- and β-configured glycosides could be obtained from the corresponding stereochemically pure β- and α-glycosyl donors with high yields and good to excellent stereoselectivities, respectively. This method accommodates a variety of glycosyl donors and alcoholic acceptors, leading to both 1,2-cis and 1,2-trans glycosidic linkages, and has been applied to the convenient preparation of a series of linear arabinan glycans. Mechanistic investigations reveal that the counteranion could bridge the diarylurea residue on the phosphine ligand with the alcoholic acceptor via hydrogen bond interactions, thereby permitting stereoinvertive displacement at the anomeric position.

β-glucan: a potent adjuvant in immunotherapy for digestive tract tumors

The immunotherapy for gastrointestinal tumors, as a significant research direction in the field of oncology treatment in recent years, has garnered extensive attention due to its potential therapeutic efficacy and promising clinical application prospects. Recent advances in immunotherapy notwithstanding, challenges persist, such as side effects, the complexity of the tumor immune microenvironment, variable patient responses, and drug resistance. Consequently, there is a pressing need to explore novel adjunctive therapeutic modalities. β-glucan, an immunomodulatory agent, has exhibited promising anti-tumor efficacy in preclinical studies involving colorectal cancer, pancreatic cancer, and gastric cancer, while also mitigating the adverse reactions associated with chemotherapy and enhancing patients' quality of life. However, further clinical and fundamental research is warranted to comprehensively evaluate its therapeutic potential and underlying biological mechanisms. In the future, β-glucan holds promise as an adjunctive treatment for gastrointestinal tumors, potentially bringing significant benefits to patients.

Bottom-Up Synthesized Glucan Materials: Opportunities from Applied Biocatalysis

Linear d-glucans are natural polysaccharides of simple chemical structure. They are comprised of d-glucosyl units linked by a single type of glycosidic bond. Noncovalent interactions within, and between, the d-glucan chains give rise to a broad variety of macromolecular nanostructures that can assemble into crystalline-organized materials of tunable morphology. Structure design and functionalization of d-glucans for diverse material applications largely relies on top-down processing and chemical derivatization of naturally derived starting materials. The top-down approach encounters critical limitations in efficiency, selectivity, and flexibility. Bottom-up approaches of d-glucan synthesis offer different, and often more precise, ways of polymer structure control and provide means of functional diversification widely inaccessible to top-down routes of polysaccharide material processing. Here the natural and engineered enzymes (glycosyltransferases, glycoside hydrolases and phosphorylases, glycosynthases) for d-glucan polymerization are described and the use of applied biocatalysis for the bottom-up assembly of specific d-glucan structures is shown. Advanced material applications of the resulting polymeric products are further shown and their important role in the development of sustainable macromolecular materials in a bio-based circular economy is discussed.

An Overview on Mushroom Polysaccharides: Health-promoting Properties, Prebiotic and Gut Microbiota Modulation Effects and Structure-function Correlation

Mushroom polysaccharides are recognized as "biological response modifiers". Besides several bioactivities, a growing interest in their prebiotic potential has been raised due to the gut microbiota modulation potential. This review comprehensively summarizes mushroom polysaccharides' biological properties, structure-function relationship, and underlying mechanisms. It provides a recent overview of the key findings in the field (2018-2024). Key findings and limitations on structure-function correlation are discussed. Although most studies focus on β-glucans or extracts, α-glucans and chitin have gained interest. Prebiotic capacity has been associated with α-glucans and chitin, while antimicrobial and wound healing potential is attributed to chitin. However, further research is of utmost importance. Human fecal fermentation is the most reported approach to assess prebiotic potential, indicating impacts on intestinal biological, mechanical, chemical and immunological barriers. Gut microbiota dysbiosis has been directly connected with intestinal, cardiovascular, metabolic, and neurological diseases. Concerning gut microbiota modulation, animal experiments have suggested proinflammatory cytokines reduction and redox balance re-establishment. Most literature focused on the anticancer and immunomodulatory potential. However, anti-inflammatory, antimicrobial, antiviral, antidiabetic, hypocholesterolemic, antilipidemic, antioxidant, and neuroprotective properties are discussed. A significant overview of the gaps and research directions in synergistic effects, underlying mechanisms, structure-function correlation, clinical trials and scientific data is also given.

Glucans and applications in drug delivery

Glucan is a natural polysaccharide widely distributed in cereals and microorganisms that has various biological activities, including immunomodulatory, anti-infective, anti-inflammatory, and antitumor activities. In addition to wide applications in the broad fields of food, healthcare, and biomedicines, glucans hold promising potential as drug delivery carrier materials or ligands. Specifically, glucan microparticles or yeast cell wall particles are naturally enclosed vehicles with an interior cavity that can be exploited to carry and deliver drug payloads. The biological activities and targeting capacities of glucans depend largely on the recognition of glucan moieties by receptors such as dectin-1 and complement receptor 3, which are widely expressed on the cell membranes of mononuclear phagocytes, dendritic cells, neutrophils, and some lymphocytes. This review summarizes the chemical structures, sources, fundamental properties, extraction methods, and applications of these materials, with an emphasis on drug delivery. Glucans are utilized mainly as vaccine adjuvants, targeting ligands and as carrier materials for various drug entities. It is believed that glucans and glucan microparticles may be useful for the delivery of both small-molecule and macromolecular drugs, especially for potential treatment of immune-related diseases.

β-Glucan Subverts the Function of Myeloid Cells in Neonates

β-Glucan is the main component of the cell wall of pathogen-associated molecular patterns (PAMPs) including various yeast, fungi, or certain bacteria. Previous reports demonstrated that β-glucan was widely investigated as a potent immunomodulators to stimulate innate and adaptive immune responses, which indicated that it could be recommended as an effective adjuvant in immunotherapy. However, the detailed effects of β-glucan on neonatal immunity are still largely unknown. Here, we found that β-glucan did not affect the frequencies and numbers of myeloid cells in the spleen and bone marrow from neonates. Functional assay revealed that β-glucan from neonates compromised the immunosuppressive function of immature myeloid cells, which were myeloid-derived suppressor cells (MDSCs). Flow cytometry or gene expression analysis revealed that β-glucan-derived polymorphonuclear (PMN)-MDSCs produced lower level of reactive oxygen species (ROS) and arginase-1 (Arg1) in neonatal mice. Furthermore, β-glucan administration significantly decreased the frequency and ROS level of PMN-MDSCs in vitro. These observations suggest that β-glucan facilitates the maturation of myeloid cells in early life, which may contribute to its beneficial effects against immune disorders later in life.

Architecture, Function, Regulation, and Evolution of α-Glucans Metabolic Enzymes in Prokaryotes

Bacteria have acquired sophisticated mechanisms for assembling and disassembling polysaccharides of different chemistry. α-d-Glucose homopolysaccharides, so-called α-glucans, are the most widespread polymers in nature being key components of microorganisms. Glycogen functions as an intracellular energy storage while some bacteria also produce extracellular assorted α-glucans. The classical bacterial glycogen metabolic pathway comprises the action of ADP-glucose pyrophosphorylase and glycogen synthase, whereas extracellular α-glucans are mostly related to peripheral enzymes dependent on sucrose. An alternative pathway of glycogen biosynthesis, operating via a maltose 1-phosphate polymerizing enzyme, displays an essential wiring with the trehalose metabolism to interconvert disaccharides into polysaccharides. Furthermore, some bacteria show a connection of intracellular glycogen metabolism with the genesis of extracellular capsular α-glucans, revealing a relationship between the storage and structural function of these compounds. Altogether, the current picture shows that bacteria have evolved an intricate α-glucan metabolism that ultimately relies on the evolution of a specific enzymatic machinery. The structural landscape of these enzymes exposes a limited number of core catalytic folds handling many different chemical reactions. In this Review, we present a rationale to explain how the chemical diversity of α-glucans emerged from these systems, highlighting the underlying structural evolution of the enzymes driving α-glucan bacterial metabolism.

Structural variety of glucans from Ganoderma lucidum fruiting bodies

Ganoderma lucidum, widely used in traditional medicine, has several biological properties. Polysaccharides, mainly glucans, are known as one of its main bioactive compounds. Consequently, the achievement and chemical investigation of such molecules are of pharmaceutical interest. Herein, we obtained water-insoluble and water-soluble polysaccharides from G. lucidum by alkaline extraction. Fractionation process yielded three fractions (GLC-1, GLC-2, and GLC-3). All samples showed to be composed mainly of glucans. GLC-1 is a linear (1 → 3)-linked β-glucan; GLC-2 is a mixture of three different linear polysaccharides: (1 → 3)-β-glucan, (1 → 3)-α-glucan, and (1 → 4)-α-mannan; while GLC-3 is a branched β-glucan with a (1 → 4)-linked main chain, which is branched at O-3 or O-6 by (1 → 3)- or (1 → 6)-linked side chains. This research reports the variability of glucans in Ganoderma lucidum fruiting bodies and applicable methodologies to obtain such molecules. These polysaccharides can be further applied in biological studies aiming to investigate how their chemical differences may affect their biological properties.

The function and application of edible fungal polysaccharides

Edible fungi, commonly known as mushrooms, are precious medicinal and edible homologous gifts from nature to us. Edible fungal polysaccharides (EFPs) are a variety of bioactive macromolecular which isolated from fruiting bodies, mycelia or fermentation broths of edible or medicinal fungus. Increasing researches have confirmed that EFPs possess multiple biological activities both in vitro and in vivo settings, including antioxidant, antiviral, anti-inflammatory, immunomodulatory, anti-tumor, hypoglycemic, hypolipidemic, and regulating intestinal flora activities. As a result, they have emerged as a prominent focus in the healthcare, pharmaceutical, and cosmetic industries. Fungal EFPs have safe, non-toxic, biodegradable, and biocompatible properties with low immunogenicity, bioadhesion ability, and antibacterial activities, presenting diverse potential applications in the food industries, cosmetic, biomedical, packaging, and new materials. Moreover, varying raw materials, extraction, purification, chemical modification methods, and culture conditions can result in variances in the structure and biological activities of EFPs. The purpose of this review is to provide comprehensively and systematically organized information on the structure, modification, biological activities, and potential applications of EFPs to support their therapeutic effects and health functions. This review provides new insights and a theoretical basis for prospective investigations and advancements in EFPs in fields such as medicine, food, and new materials.

Role of beta-(1→3)(1→6)-D-glucan derived from yeast on natural killer (NK) cells and breast cancer cell lines in 2D and 3D cultures

BACKGROUND

Beta-(1,3)(1,6)-D-glucan is a complex polysaccharide, which is found in the cell wall of various fungi, yeasts, bacteria, algae, barley, and oats and has immunomodulatory, anticancer and antiviral effects. In the present study, we investigated the effect of beta-(1,3)(1,6)-D-glucan derived from yeast on the proliferation of primary NK cells and breast cancer cell lines in 2D and 3D models, and on the cytotoxicity of primary NK cells against breast cancer cell lines in 2D and 3D models.

METHODS

In this study, we investigated the effects of different concentrations of yeast-derived beta-(1→3)(1→6)-D-glucan on the proliferation and cytotoxicity of human NK cells and breast cancer cell lines in 2D and 3D models using the XTT cell proliferation assay and the CellTiter-Glo® 2.0 assay to determine the cytotoxicity of human NK cells on breast cancer cell lines in 2D and 3D models.

RESULTS

We found that the co-incubation of NK cells with beta-glucan in the absence of IL2 at 48 h significantly increased the proliferation of NK cells, whereas the co-incubation of NK cells with beta-glucan in the presence of IL2 (70 U/ml) increased the proliferation of NK cells but not significantly. Moreover, beta-glucan significantly inhibited the proliferation of breast cancer cell lines in 2D model and induced a weak, non-significant growth inhibitory effect on breast cancer multicellular tumor spheroids (3D). In addition, the cytotoxicity of NK cells against breast cancer cell lines was examined in 2D and 3D models, and beta-glucan significantly increased the cytotoxicity of NK cells against MCF-7 (in 2D).

CONCLUSIONS

Yeast derived beta-(1,3)(1,6)-D-glucan could contribute to the treatment of cancer by enhancing NK cell immune response as well as contributing to inhibition of breast cancer cell growth.

β-Glucans obtained from fungus for wound healing: A review

The cell surface of fungus contains a large number of β-glucans, which exhibit various biological activities such as immunomodulatory, anti-inflammatory, and antioxidation. Fungal β-glucans with highly branched structure show great potential as wound healing reagents, because they can stimulate the expression of many immune- and inflammatory-related factors beneficial to wound healing. Recently, the wound healing ability of many fungal β-glucans have been investigated in animals and clinical trials. Studies have proved that fungal β-glucans can promote fibroblasts proliferation, collagen deposition, angiogenesis, and macrophage infiltration during the wound healing process. However, the development of fungal β-glucans as wound healing reagents is not systematically reviewed till now. This review discusses the wound healing studies of β-glucans obtained from different fungal species. The structure characteristics, extraction methods, and biological functions of fungal β-glucans with wound healing ability are summarized. Researches about fungal β-glucan-containing biomaterials and structurally modified β-glucans for wound healing are also involved.

Crude Polysaccharides from Mushrooms Elicit an Anti-Allergic Effect Against Type 1 Allergy In Vitro

Type 1 allergic disease is a global challenge, hence the search for alternative therapies. Mushrooms have several medicinal and health benefits. However, scant data exist on the anti-allergic properties of polysaccharides from fruiting bodies (FB) and mycelia of mushrooms. We used an in vitro co-culture system comprising Caco-2 cells (intestinal epithelial colorectal carcinoma cell line) and RBL-2H3 cells (cell line from rat basophilic leukemia cells). Reduction in degranulation of mast cells indicated anti-allergy properties. The inhibitory effect of crude polysaccharides from different mushroom FB and mycelia on β-hexosaminidase release from RBL-2H3 cells was measured. Results showed that crude polysaccharides from the FB of Inonotus obliquus exhibited a significant inhibitory effect on β-hexosaminidase release and lowered it by 16%. Polysaccharides from the FB of Lentinus squarrosulus, and Pleurotus ostreatus did not exhibit a significant reduction in β-hexosaminidase. However, crude polysaccharides from their mycelia had a significant inhibitory effect, resulting in up to a 23% reduction in β-hexosaminidase activity. Among fungi showing degranulation properties, crude polysaccharides from their mycelia showed more potent action against degranulation than their corresponding FB. Polysaccharides extracted from FB and or mycelia, of selected mushrooms, possess anti-allergic properties that could be harnessed for use in alternative allergy therapies.

Investigation of the structural and immunomodulatory properties of alkali-soluble β-glucans from Pleurotus eryngii fruiting bodies

Fungal β-glucans have received a lot of interest due to their proinflammatory activity towards cells of the innate immune system. Although commonly described as (1➔3)-β-glucans with varying degree of (1➔6)-branching, the fungal β-glucans constitute a diverse polysaccharide class. In this study, the alkali-soluble β-glucans from the edible mushroom Pleurotus eryngii were extracted and characterized by GC, GC-MS and 2D NMR analyses. The extracts contain several structurally different polysaccharides, including a (1➔3)-β-d-glucan with single glucose units attached at O-6, and a (1➔6)-β-d-glucan, possibly branched at O-3. The immunomodulatory activities of the P. eryngii extracts were assessed by investigating their ability to bind to the receptor dectin-1, and their ability to induce production of the proinflammatory cytokines TNF-α, IL-6 and IL-1β in LPS-differentiated THP-1 cells. Although the samples were able to bind to the dectin-1a receptor, they did not induce production of significant levels of cytokines in the THP-1 cells. Positive controls of yeast-derived (1➔3)-β-d-glucans with branches at O-6 induced cytokine production in the cells. Thus, it appears that the P. eryngii β-glucans are unable to induce production of proinflammatory cytokines in LPS-differentiated THP-1 cells, despite being able to activate the human dectin-1a receptor.

Evaluation of the "Relative Ordered Structure of Hericium erinaceus Polysaccharide" from Different Origins: Based on Similarity and Dissimilarity

Polysaccharides are organic compounds widely distributed in nature, but structural order and disorder remain a formidable problem. In this study, based on the theoretical framework of the "relative ordered structure of polysaccharide" proposed in our previous work, the structural order of Hericium erinaceus polysaccharides from different regions was evaluated by FT-IR, methylation analysis, and 1H NMR spectroscopy combined with chemometric methods. The results of principal component analysis and heatmap cluster analysis revealed that 18-subfractions exhibit four different structural types with representative glycoside linkage types: fucogalactoglucan, glucofucogalactan, fucoglucan, and glucan. The main chain of heteroglucans often consists of β-(1 → 6)-Glcp, β-(1 → 4)-Glcp, and β-(1 → 3)-Glcp residues, which are predominantly substituted at the O-3 and O-6 positions. The main chain structure of heterogalactans is α-(1 → 6)-Galp residues, which may be replaced by Fucp and Galp residues at O-2. Overall, our findings demonstrate the validity of the "relative ordered structure of polysaccharide" in Hericium erectus polysaccharides and simplify the complexity of polysaccharide structures.

Production of Exopolysaccharide-Based Porous Structures for Biomedical Applications: A Review

Exopolysaccharides, obtained from microorganisms as fermentation products, are interesting candidates for biomedical applications as scaffolds: they are biocompatible, nontoxic, antimicrobial, antitumor materials. To produce exopolysaccharide-based scaffolds, sol-gel technology could be used, which ends with the removal of the liquid phase from the polymeric network (i.e., the drying step). The aim of this review is to point out the most relevant strengths and weaknesses of the different drying techniques, focusing attention on the production of exopolysaccharide-based porous structures. Among these drying processes, supercritical carbon dioxide-assisted drying is the most promising strategy to obtain dried gels to use in the biomedical field: it produces highly porous and lightweight devices with outstanding surface areas and regular microstructure and nanostructure (i.e., aerogels). As a result of the analysis carried out in the present work, it emerged that supercritical technologies should be further explored and applied to the production of exopolysaccharide-based nanostructured scaffolds. Moving research towards this direction, exopolysaccharide utilization could be intensified and extended to the production of high added-value devices.

Exploring the partial degradation of polysaccharides: Structure, mechanism, bioactivities, and perspectives

Polysaccharides are promising biomolecules with lowtoxicity and diverse bioactivities in food processing and clinical drug development. However, an essential prerequisite for their applications is the fine structure characterization. Due to the complexity of polysaccharide structure, partial degradation is a powerful tool for fine structure analysis, which can effectively provide valid information on the structure of backbone and branching glycosidic fragments of complex polysaccharides. This review aims to conclude current methods of partial degradation employed for polysaccharide structural characterization, discuss the molecular mechanisms, and describe the molecular structure and solution properties of degraded polysaccharides. In addition, the effects of polysaccharide degradation on the conformational relationships between the molecular structure and bioactivities, such as antioxidant, antitumor, and immunomodulatory activities, are also discussed. Finally, we summarize the prospects and current challenges for the partial degradation of polysaccharides. This review will be of great value for the scientific elucidation of polysaccharide fine structures and potential applications.

Some new insights into the biological activities of carboxymethylated polysaccharides from Lasiodiplodia theobromae

BACKGROUND

Carboxymethylated Lasiodiplodan (LaEPS-C), Lasiodiplodia theobromae β-glucan exopolysaccharide derivative, has a well-known range of biological activities. Compared to LaEPS-C, its fractions, Linear (LLaEPS-C) and Branched (BLaEPS-C), have biological potentialities scarcely described in the literature. So, in this study, we investigate the immunomodulatory, antiviral, antiproliferative, and anticoagulant activities of LLaEPS-C and BLaEPS-C and compare them to the LaEPS-C.

METHODS

LaEPS was obtained from L. theobromae MMBJ. After carboxymethylation, LaEPS-C structural characteristics were confirmed by Elementary Composition Analysis by Energy Dispersive X-Ray Detector (EDS), Fourier Transform Infrared (FTIR), and Nuclear Magnetic Resonance (NMR). The immunomodulatory activity on cytokine secretion was evaluated in human monocyte-derived macrophage cultures. The antiviral activity was evaluated by Hep-2 cell viability in the presence or absence of hRSV (human respiratory syncytial virus). In vitro antiproliferative activity was tested by sulforhodamine B assay. The anticoagulant activity was determined by APTT (Activated Partial Thromboplastin Time) and PT (Prothrombin Time).

RESULTS

LaEPS-C showed low macrophage cell viability only at 100 µg/mL (52.84 ± 24.06, 48 h), and LLaEPS-C presented no effect. Conversely, BLaEPS-C showed cytotoxicity from 25 to 100 µg/mL (44.36 ± 20.16, 40.64 ± 25.55, 33.87 ± 25.16; 48 h). LaEPS-C and LLaEPS-C showed anti-inflammatory activity. LaEPS-C presented this at 100 µg/mL (36.75 ± 5.53, 48 h) for IL-10, and LLaEPS-C reduces TNF-α cytokine productions at 100 µg/mL (18.27 ± 5.80, 48 h). LLaEPS-C showed an anti-hRSV activity (0.7 µg/ml) plus a low cytotoxic activity for Hep-2 cells (1.4 µg/ml). LaEPS-C presented an antiproliferative activity for NCI-ADR/RES (GI50 65.3 µg/mL). A better PT was achieved for LLaEPS-C at 5.0 µg/mL (11.85 ± 0.87s).

CONCLUSIONS

These findings demonstrated that carboxymethylation effectively improves the biological potential of the LaEPS-C and their fractions. From those polysaccharides tested, LLaEPS provided the best results with low toxicity for anti-inflammatory, antiviral, and anticoagulant activities.

Effect of the β-glucan from Lentinus edodes on colitis-associated colorectal cancer and gut microbiota

Colorectal cancer is the third most common cancer in the world, and therapies with safety are in great need. In this study, the β-glucan isolated from Lentinus edodes was successfully fractionated into three fractions with different weight-average molecular weight (M_w) by ultrasonic degradation and used for the treatment of colorectal cancer. In our findings, the β-glucan was successfully degraded with the M_w decreased from 2.56 × 10⁶ Da to 1.41 × 10⁶ Da, exhibiting the triple helix structure without conformation disruption. The in vitro results indicate that β-glucan fractions inhibited colon cancer cell proliferation, induced colon cancer cell apoptosis, and reduced inflammation. The in vivo results based on Azoxymethane (AOM)/dextran sulfate sodium (DSS) mouse model demonstrate that the lower-molecular weight β-glucan fraction showed stronger anti-inflammatory and anti-colon cancer activities by reconstructing intestinal mucosal barrier, increasing short chain fatty acids (SCFAs) content, regulating metabolism of gut microbiota, and rebuilding the gut microbiota structure with the increased Bacteroides and the decreased Proteobacteria at the phylum level, as well as with the decreased Helicobacter and the increased Muribaculum at the genus level. These findings provide scientific basis for using the β-glucan to regulate gut microbiota as an alternative strategy in the clinical treatment of colon cancer.

Recent Advances in the Preparation, Structure, and Biological Activities of β-Glucan from Ganoderma Species: A Review

Ganoderma has served as a valuable food supplement and medicinal ingredient with outstanding active compounds that are essential for human protection against chronic diseases. Modern pharmacology studies have proven that Ganoderma β-d-glucan exhibits versatile biological activities, such as immunomodulatory, antitumor, antioxidant, and antiviral properties, as well as gut microbiota regulation. As a promising polysaccharide, β-d-glucan is widely used in the prevention and treatment of various diseases. In recent years, the extraction, purification, structural characterization, and pharmacological activities of polysaccharides from the fruiting bodies, mycelia, spores, and fermentation broth of Ganoderma species have received wide attention from scholars globally. Unfortunately, comprehensive studies on the preparation, structure and bioactivity, toxicology, and utilization of β-d-glucans from Ganoderma species still need to be further explored, which may result in limitations in future sustainable industrial applications of β-d-glucans. Thus, this review summarizes the research progress in recent years on the physicochemical properties, structural characteristics, and bioactivity mechanisms of Ganoderma β-d-glucan, as well as its toxicological assessment and applications. This review is intended to provide a theoretical basis and reference for the development and application of β-d-glucan in the fields of pharmaceuticals, functional foods, and cosmetics.

Recent Progress in 1,2-cis glycosylation for Glucan Synthesis

Controlling the stereoselectivity of 1,2-cis glycosylation is one of the most challenging tasks in the chemical synthesis of glycans. There are various 1,2-cis glycosides in nature, such as α-glucoside and β-mannoside in glycoproteins, glycolipids, proteoglycans, microbial polysaccharides, and bioactive natural products. In the structure of polysaccharides such as α-glucan, 1,2-cis α-glucosides were found to be the major linkage between the glucopyranosides. Various regioisomeric linkages, 1→3, 1→4, and 1→6 for the backbone structure, and 1→2/3/4/6 for branching in the polysaccharide as well as in the oligosaccharides were identified. To achieve highly stereoselective 1,2-cis glycosylation, including α-glucosylation, a number of strategies using inter- and intra-molecular methodologies have been explored. Recently, Zn salt-mediated cis glycosylation has been developed and applied to the synthesis of various 1,2-cis linkages, such as α-glucoside and β-mannoside, via the 1,2-cis glycosylation pathway and β-galactoside 1,4/6-cis induction. Furthermore, the synthesis of various structures of α-glucans has been achieved using the recent progressive stereoselective 1,2-cis glycosylation reactions. In this review, recent advances in stereoselective 1,2-cis glycosylation, particularly focused on α-glucosylation, and their applications in the construction of linear and branched α-glucans are summarized.

Insights into the Antifungal Properties of Myxobacteria Outer Membrane β-1,6-Glucanase

Fungal cell wall decomposition enzymes exhibit great potential for the development of efficient antifungal agents. However, their practical application is restricted due to incomplete understanding of the action mode. In our previous study, we identified that a novel outer membrane (OM) β-1,6-glucanase GluM is deployed by predatory myxobacteria to feed on fungi. In this work, we provide deep insights into the antifungal mechanism of β-1,6-glucanase and its potential in improving plant disease resistance. The fungal cell wall decomposition ability of GluM resulted in irregular hyphae morphology, changed chitin distribution, increased membrane permeability, and leakage of cell constituents in Magnaporthe oryzae Guy11. Under the attack pattern, the cell wall integrity pathway was activated by strain Guy11 for self-protection. GluM exhibited a distinct endo-model toward fungal cell wall; the favorite substrate of GluM toward fungal β-1,6-glucan may give reason for its efficient antifungal activity compared with Trichoderma β-1,6-glucanase. Moreover, released glucans from GluM hydrolysis of fungal cell wall functioned as an elicitor and induced rice immunity by means of jasmonic acid pathway. Based on the dual roles of antifungal properties, gluM transgenic plants conferred enhanced resistance against fungal infection.

Sustainable production and pharmaceutical applications of β-glucan from microbial sources

β-glucans are a large class of complex polysaccharides found in abundant sources. Our dietary sources of β-glucans are cereals that include oats and barley, and non-cereal sources can consist of mushrooms, microalgae, bacteria, and seaweeds. There is substantial clinical interest in β-glucans; as they can be used for a variety of diseases including cancer and cardiovascular conditions. Suitable sources of β-glucans for biopharmaceutical applications include bacteria, microalgae, mycelium, and yeast. Environmental factors including culture medium can influence the biomass and ultimately β-glucan content. Therefore, cultivation conditions for the above organisms can be controlled for sustainable enhanced production of β-glucans. This review discusses the various sources of β-glucans and their cultivation conditions that may be optimised to exploit sustainable production. Finally, this article discusses the immune-modulatory potential of β-glucans from these sources.

A review of Ganoderma lucidum polysaccharides: Health benefit, structure-activity relationship, modification, and nanoparticle encapsulation

Ganoderma lucidum polysaccharides possess unique functional properties. Various processing technologies have been used to produce and modify G. lucidum polysaccharides to improve their yield and utilization. In this review, the structure and health benefits were summarized, and the factors that may affect the quality of G. lucidum polysaccharides were discussed, including the use of chemical modifications such as sulfation, carboxymethylation, and selenization. Those modifications improve the physicochemical characteristics and utilization of G. lucidum polysaccharides, and make them more stable that could be used as functional biomaterials to encapsulate active substances. Ultimate, G. lucidum polysaccharide-based nanoparticles were designed to deliver various functional ingredients to achieve better health-promoting effects. Overall, this review presents an in-depth summary of current modification strategies and offers new insights into the effective processing techniques to develop G. lucidum polysaccharide-rich functional foods or nutraceuticals.

Immunomodulatory Effect and Biological Significance of β-Glucans

β-glucan, one of the homopolysaccharides composed of D-glucose, exists widely in cereals and microorganisms and possesses various biological activities, including anti-inflammatory, antioxidant, and anti-tumor properties. More recently, there has been mounting proof that β-glucan functions as a physiologically active "biological response modulator (BRM)", promoting dendritic cell maturation, cytokine secretion, and regulating adaptive immune responses-all of which are directly connected with β-glucan-regulated glucan receptors. This review focuses on the sources, structures, immune regulation, and receptor recognition mechanisms of β-glucan.

Preparation of Albatrellus ovinus β-Glucan Microparticles with Dectin-1a Binding Properties

Fungal β-glucans are compounds with the potential to activate the innate immune system, in part through binding to the receptor dectin-1. In the present study, small-scale methods for preparing dectin-1a binding microparticles from Albatrellus ovinus alkali-soluble β-glucans were investigated. Mechanical milling was time-consuming and yielded large particles with wide size distributions. Precipitation was more successful: the β-glucan was dissolved in 1 M NaOH, diluted, and precipitated in 1:1 mol equiv HCl. This yielded particles in sizes ranging from 0.5-2 μm. The dectin-1a binding activity was determined using HEK-Blue reporter cells. The prepared particles were able to bind to dectin-1a to the same extent as baker's-yeast-derived β-glucan particles. The precipitation method was convenient as a quick method for small-scale preparation of β-glucan microparticle dispersions from mushroom β-glucans.

Efficient production and skincare activity evaluation of schizophyllan, a β-glucan derived from Schizophyllum commune NTU-1

Schizophyllan (SPG), a β-glucan produced by the fungus Schizophyllum commune, possesses a β-(1 → 3)-linked backbone with single β-(1 → 6)-linked glucose side chains at approximately every third residue. In this study, we screened SPG-producing strains of S. commune from different provinces in China. A candidate strain (NTU-1) with a high SPG yield was chosen, and the fermentation conditions were optimized. The optimal carbon and nitrogen sources were sucrose (40 g/L) and yeast extract (20 g/L), respectively. The optimal conditions for pH and temperature were 5.0 and 28 °C, respectively. Inclusion of 0.2 mg/L of 2,4-Dichlorophenoxyacetic acid in the medium further increased the SPG concentration. In a 5-L bioreactor, the fermentation cycle was reduced from the initial seven days to five days, and the concentration of SPG obtained was 21.3 g/L, which is the highest reported to date. In addition, we evaluated the bioactivity of the SPG prepared using strain NTU-1. The results showed that SPG had certain characteristics of anti-oxidation, anti-photoaging, and inhibition of melanin production, making it a promising reagent for skin care.

Fungal β-Glucan-Based Nanotherapeutics: From Fabrication to Application

Fungal β-glucans are naturally occurring active macromolecules used in food and medicine due to their wide range of biological activities and positive health benefits. Significant research efforts have been devoted over the past decade to producing fungal β-glucan-based nanomaterials and promoting their uses in numerous fields, including biomedicine. Herein, this review offers an up-to-date report on the synthetic strategies of common fungal β-glucan-based nanomaterials and preparation methods such as nanoprecipitation and emulsification. In addition, we highlight current examples of fungal β-glucan-based theranostic nanosystems and their prospective use for drug delivery and treatment in anti-cancer, vaccination, as well as anti-inflammatory treatments. It is anticipated that future advances in polysaccharide chemistry and nanotechnology will aid in the clinical translation of fungal β-glucan-based nanomaterials for the delivery of drugs and the treatment of illnesses.

Perspectives in the Application of High, Medium, and Low Molecular Weight Oat β-d-Glucans in Dietary Nutrition and Food Technology-A Short Overview

For centuries human civilization has cultivated oats, and now they are consumed in various forms of food, from instant breakfasts to beverages. They are a nutrient-rich food containing linear mixed-linkage (1 → 3) (1 → 4)-β-d-glucans, which are relatively well soluble in water and responsible for various biological effects: the regulation of the blood cholesterol level, as well as being anti-inflammatory, prebiotic, antioxidant, and tumor-preventing. Numerous studies, especially in the last two decades, highlight the differences in the biological properties of the oat β-d-glucan fractions of low, medium, and high molecular weight. These fractions differ in their features due to variations in bioavailability related to the rheological properties of these polysaccharides, and their association with food matrices, purity, and mode of preparation or modification. There is strong evidence that, under different conditions, the molecular weight may determine the potency of oat-extracted β-d-glucans. In this review, we intend to give a concise overview of the properties and studies of the biological activities of oat β-d-glucan preparations depending on their molecular weight and how they represent a prospective ingredient of functional food with the potential to prevent or modulate various pathological conditions.

The Mushroom Glucans: Molecules of High Biological and Medicinal Importance

Carbohydrates, including polysaccharide macromolecules, are the main constituents of the fungal cell wall. Among these, the homo- or heteropolymeric glucan molecules are decisive, as they not only protect fungal cells but also have broad, positive biological effects on the animal and human bodies. In addition to the beneficial nutritional properties of mushrooms (mineral elements, favorable proteins, low fat and energy content, pleasant aroma, and flavor), they have a high glucan content. Folk medicine (especially in the Far East) used medicinal mushrooms based on previous experience. At the end of the 19th century, but mainly since the middle of the 20th century, progressively more scientific information has been published. Glucans from mushrooms are polysaccharides that contain sugar chains, sometimes of only one kind (glucose), sometimes having several monosaccharide units, and they have two (α and β) anomeric forms (isomers). Their molecular weights range from 104 to 105 Da, and rarely 106 Da. X-ray diffraction studies were the first to determine the triple helix configuration of some glucans. It seems that the existence and integrity of the triple helix structure are criteria for their biological effects. Different glucans can be isolated from different mushroom species, and several glucan fractions can be obtained. The biosynthesis of glucans takes place in the cytoplasm, the processes of initiation and then chain extension take place with the help of the glucan synthase enzyme complex (EC 2.4.1.34), and the sugar units are provided by sugar donor UDPG molecules. The two methods used today for glucan determination are the enzymatic and Congo red methods. True comparisons can only be made using the same method. Congo red dye reacts with the tertiary triple helix structure, and the resulting glucan content better reflects the biological value of glucan molecules. The biological effect of β-glucan molecules is proportional to the integrity of the tertiary structure. The glucan contents of the stipe exceed the values of the caps. The glucan levels of individual fungal taxa (including varieties) differ quantitatively and qualitatively. This review presents in more detail the glucans of lentinan (from Lentinula edodes), pleuran (from Pleurotus ostreatus), grifolan (from Grifola frondose), schizophyllan (from Schizophyllum commune), and krestin (from Trametes versicolor), along with their main biological effects.

Bioactive Compounds from Medicinal Mushrooms

Research progress of active compounds and biological activities of medicinal mushroom-Ganoderma spp., Hericium spp., Phellinus spp., and Cordyceps spp. were summarized systematically. The main active compounds of medicinal mushrooms included are polysaccharides, proteins, triterpenes, meroterpenoids, polyphenols and nitrogen-containing compounds. The biological activities of the compounds cover immunomodulatory activity, antitumor activity, hypoglycemic activity, hepatoprotective activity, and activity of regulation of intellectual flora.

A Review of Development and Utilization for Edible Fungal Polysaccharides: Extraction, Chemical Characteristics, and Bioactivities

Edible fungi, commonly known as mushrooms, are precious medicinal and edible homologous gifts from nature to us. Because of their distinctive flavor and exceptional nutritional and medicinal value, they have been a frequent visitor to people’s dining tables and have become a hot star in the healthcare, pharmaceutical, and cosmetics industries. Edible fungal polysaccharides (EFPs) are an essential nutrient for edible fungi to exert bioactivity. They have attracted much attention because of their antioxidant, immunomodulatory, antitumor, hypoglycemic, and hypolipidemic bioactivities. As a result, EFPs have demonstrated outstanding potential over the past few decades in various disciplines, including molecular biology, immunology, biotechnology, and pharmaceutical chemistry. However, the complexity of EFPs and the significant impact of mushroom variety and extraction techniques on their bioactivities prevents a complete investigation of their biological features. Therefore, the authors of this paper thoroughly reviewed the comparison of different extraction methods of EFPs and their advantages and disadvantages. In addition, the molecular weight, monosaccharide composition, and glycosidic bond type and backbone structure of EFPs are described in detail. Moreover, the in vitro and in vivo bioactivities of EFPs extracted by different methods and their potential regulatory mechanisms are summarized. These provide a valuable reference for improving the extraction process of EFPs and their production and development in the pharmaceutical field.

Sulfonated (1 → 6)-β-d-Glucan (Lasiodiplodan): A Promising Candidate against the Acyclovir-Resistant Herpes Simplex Virus Type 1 (HSV-1) Strain

Herpes simplex virus type 1 (HSV-1) is a persistent human pathogen, and the emergence of strains resistant to Acyclovir (ACV, reference drug) shows the urgency to develop new treatments. We report the antiherpetic mechanism of the action of lasiodiplodan (LAS-N, (1 → 6)-β-d-glucan) and its sulfonated derivative (LAS-S3) in vitro and in vivo. LAS-S3 showed anti-HSV-1 action with high selectivity indices for HSV-1 KOS (88.1) and AR (189.2), sensitive and resistant to ACV, respectively. LAS-S3 inhibited >80% of HSV-1 infection in different treatment protocols (virucidal, adsorption inhibition, and post-adsorption effects), even at low doses, and showed a preventive effect and DNA and protein synthesis inhibition. The antiherpetic effect was confirmed in vivo by the cosmetic LAS-S3-CRÈME decreasing cutaneous lesions of HSV-1, including the AR strain. LAS-S3 possessed a broad-spectrum mechanism of action acting in the early and post-adsorption stages of HSV-1 infection, and LAS-S3-CRÈME is a potential antiherpetic candidate for patients infected by HSV-1-resistant strains.

Agrobacterium sp. ZX09 β-Glucan Attenuates Enterotoxigenic Escherichia coli-Induced Disruption of Intestinal Epithelium in Weaned Pigs

To explore the protective effect of dietary β-glucan (BGL) supplementation on intestinal epithelium exposure to enterotoxigenic Escherichia coli (ETEC), thirty-two weaned pigs were assigned to four groups. Pigs were fed with a basal diet or basal diet containing 500 mg/kg BGL, and were orally infused with ETEC or culture medium. Results showed BGL supplementation had no influence on growth performance in weaned pigs. However, BGL supplementation increased the absorption of D-xylose, and significantly decreased the serum concentrations of D-lactate and diamine oxidase (DAO) in the ETEC-challenged pigs (p < 0.05). Interestingly, BGL significantly increased the abundance of the zonula occludens-1-(ZO-1) in the jejunal epithelium upon ETEC challenge (p < 0.05). BGL supplementation also increased the number of S-phase cells and the number of sIgA-positive cells, but significantly decreased the number of total apoptotic cells in the jejunal epithelium upon ETEC challenge (p < 0.05). Moreover, BGL significantly increased the duodenal catalase (CAT) activity and the ileal total superoxide dismutase (T-SOD) activity in the ETEC-challenged pigs (p < 0.05). Importantly, BGL significantly decreased the expression levels of critical inflammation related proteins such as the tumor necrosis factor-α (TNF-α), interlukin-6 (IL-6), myeloid differentiation factor 88 (MyD88), and nuclear factor-κB (NF-κB) in the jejunal and ileal mucosa upon ETEC challenge (p < 0.05). BGL also elevated the propanoic acid content and the abundance of Lactobacillus and Bacillus in the colon upon ETEC challenge (p < 0.05). These results suggested BGL could alleviate the ETEC-induced intestinal epithelium injury, which may be associated with suppressed inflammation and improved intestinal immunity and antioxidant capacity, as well as the improved intestinal macrobiotic.

Antioxidant, antibacterial, antitumor, antifungal, antiviral, anti-inflammatory, and nevro-protective activity of Ganoderma lucidum: An overview

Ganoderma lucidum is a very medicinal mushroom that has been utilized in Oriental medicine for many years. It has a wide range of pharmacological and therapeutic properties, and has been used for many years as a health promoter. It contains various biologically active compounds that improve the immune system and have antioxidant, antitumor, anti-inflammatory, antifungal, and antimicrobial properties. Active compounds include triterpenoids and polysaccharides, as well as proteins, lipids, phenolics, sterols, etc. In the following review, we summarize briefly their biological activities, such as antioxidant, anti-bacterial, anti-fungal, antitumor, anti-viral, and anti-inflammatory activity. Although Ganoderma has a number of medicinal effects that have been confirmed by the in vitro and in vivo studies summarised in this review, there are some limitations. Clinical trials face mainly a lack of pure constituents. Accurate identification of the compounds obtained is also problematic. In addition, most of the included studies were small, and there were concerns about the methodological quality of each study. Studies have shown that Ganoderma has valuable potential for the prevention and treatment of cancer. In any case, G. lucidum cannot be used as first-line therapy for cancer.

Natural Polysaccharide-Based Nanodrug Delivery Systems for Treatment of Diabetes

In recent years, natural polysaccharides have been considered as the ideal candidates for novel drug delivery systems because of their good biocompatibility, biodegradation, low immunogenicity, renewable source and easy modification. These natural polymers are widely used in the designing of nanocarriers, which possess wide applications in therapeutics, diagnostics, delivery and protection of bioactive compounds or drugs. A great deal of studies could be focused on developing polysaccharide nanoparticles and promoting their application in various fields, especially in biomedicine. In this review, a variety of polysaccharide-based nanocarriers were introduced, including nanoliposomes, nanoparticles, nanomicelles, nanoemulsions and nanohydrogels, focusing on the latest research progress of these nanocarriers in the treatment of diabetes and the possible strategies for further study of polysaccharide nanocarriers.

Synthetic physical contact-remodeled rhizosphere microbiome for enhanced phytoremediation

Phytoremediation is a prevalent strategy to treat environmental pollution caused by heavy metals and eutrophication-related pollutants. Although rhizosphere microbiome is critical for phytoremediation, it remains a great challenge to artificially remodel rhizosphere microbiome for enhancing multiple pollutant treatment. In this study, we designed a synthetic bacterium to strengthen physical contact between natural microbes and plant roots for remodeling the Eichhornia crassipes rhizosphere microbiome during phytoremediation. The synthetic bacterium EcCMC was constructed by introducing a surface-displayed synthetic protein CMC composed of two glucan-binding domains separated by the sequence of the fluorescent protein mCherry. This synthetic bacterium strongly bound glucans and recruited natural glucan-producing bacterial and fungal cells. Microbiome and metabolomic analysis revealed that EcCMC remarkably remodeled rhizosphere microbiome and increased stress response-related metabolites, leading to the increased activity of antioxidant enzymes involved in stress resistance. The remodeled microbiome further promoted plant growth, and enhanced accumulation of multiple pollutants into the plants, with the removal efficiency of the heavy metal cadmium, total organic matters, total nitrogen, total potassium, and total phosphorus reaching up to 98%, 80%, 97%, 93%, and 90%, respectively. This study sheds a novel light on remodeling of rhizosphere microbiome for enhanced phytoremediation of water and soil systems.