Structure and inducing tumor cell apoptosis activity of polysaccharides isolated from Lentinus edodes

Insights into oral lentinan immunomodulation: Dectin-1-mediated lymphatic transport from Peyer's patch M cells to mononuclear phagocytes

Lentinan (LNT), a natural polysaccharide, has been reported to exhibit immunomodulatory effects in the intestine after oral administration. Herein, we aimed to investigate the lymphatic transport of LNT in Peyer's patches (PPs) by traceable fluorescent labeling and to explore whether/how LNT contacts related immune cells. Near-infrared imaging confirmed the absorption of LNT in the small intestinal segment and its accumulation within PPs after oral administration. Subsequently, tissue imaging confirmed that M cells are the main cells responsible for transporting LNT to PPs, and an M cell model was established to explore the involvement of Dectin-1 in the absorption process. Systematic in vitro and in vivo studies revealed that the Dectin-1 further mediates the uptake of LNT by mononuclear phagocytes in PPs. Moreover, LNT can promote the proliferation and differentiation of mononuclear phagocytes, thereby activating immune responses. In summary, this study elucidates the pharmacokinetic mechanisms by which LNT exerts oral immunomodulatory effects, providing a theoretical basis for the development and application of other polysaccharides.

Bifunctional Inhibitor Lentinan Inhibits Fibrillogenesis of Amyloid-β Protein and α-Synuclein and Alleviates Their Cytotoxicity: In Vitro and In Vivo Studies

Alzheimer's disease (AD) and Parkinson's disease (PD) are the two most common neurodegenerative diseases in the world. Misfolding of β-amyloid (Aβ) and α-synuclein (α-syn) and subsequent fibril formation are closely associated with the pathogenesis of AD and PD, respectively. Lentinan is a natural product commonly used in medicine and dietary supplements. It has potential antitumor, anti-inflammatory, and antiviral effects, but the underlying mechanism of its action on AD and PD remains unclear. In this study, lentinan inhibited the formation of Aβ and α-syn fibers in a dose-dependent manner and disrupted their mature fibers. Lentinan inhibited the conversion of Aβ and α-syn conformations to β-sheet-rich conformations. Additionally, lentinan protected Caenorhabditis elegans against damage caused by the accumulation of Aβ and α-syn aggregation and prolonged their lifespan. Notably, the beneficial effects of lentinan in AD and PD mice were also demonstrated, including ameliorating the cognitive and memory impairments in AD mice and behavioral deficits in PD mice. Finally, molecular interactions between lentinan and Aβ/α-syn pentamers were also explored using molecular docking.

Immunomodulatory, Antioxidant, and Potential Anticancer Activity of the Polysaccharides of the Fungus Fomitiporia chilensis

Fomitiporia species have aroused the interest of numerous investigations that reveal their biological activity and medicinal potential. The present investigation shows the antioxidant, anticancer, and immunomodulatory activity of acidic polysaccharides obtained from the fungus Fomitiporia chilensis. The acidic polysaccharides were obtained for acidic precipitation with 2% O-N-cetylpyridinium bromide. Chemical analysis was performed using FT-IR and GC-MS methods. The antioxidant capacity of acidic polysaccharides from F. chilensis was evaluated by scavenging free radicals with an ABTS assay. Macrophage proliferation and cytokine production assays were used to determine the immunomodulatory capacity of the polysaccharides. Anti-tumor and cytotoxicity activity was evaluated with an MTT assay in the U-937, HTC-116, and HGF-1 cell lines. The effect of polysaccharides on the cell cycle of the HCT-116 cell line was determined for flow cytometry. Fourier Transform-infrared characterization revealed characteristic absorption peaks for polysaccharides, whereas the GC-MS analysis detected three peaks corresponding to D-galactose, galacturonic acid, and D-glucose. The secreted TNF-α concentration was increased when the cell was treated with 2 mg mL-1 polysaccharides, whereas the IL-6 concentration was increased with all of the evaluated polysaccharide concentrations. A cell cycle analysis of HTC-116 treated with polysaccharides evidenced that the acidic polysaccharides from F. chilensis induce an increase in the G0/G1 cell cycle phase, increasing the apoptotic cell percentage. Results from a proteomic analysis suggest that some of the molecular mechanisms involved in their antioxidant and cellular detoxifying effects and justify their traditional use in heart diseases. Proteomic data are available through ProteomeXchange under identifier PXD048361. The study on acidic polysaccharides from F. chilensis has unveiled their diverse biological activities, including antioxidant, anticancer, and immunomodulatory effects. These findings underscore the promising therapeutic applications of acidic polysaccharides from F. chilensis, warranting further pharmaceutical and medicinal research exploration.

Impacts of preparation technologies on biological activities of edible mushroom polysaccharides - novel insights for personalized nutrition achievement

Edible mushroom polysaccharides (EMPs) as a natural macromolecular carbohydrate have a very complex structure and composition. EMPs are considered ideal candidates for developing healthy products and functional foods and have received significant research attention due to their unique physiological activities such as immunomodulatory, anti-inflammatory, anti-tumor/cancer, gut microbiota regulation, metabolism improvement, and nervous system protection. The structure and monosaccharide composition of edible mushroom polysaccharides have an unknown relationship with their functional activity, which has not been widely studied. Therefore, we summarized the preparation techniques of EMPs and discussed the association between functional activity, preparation methods, structure and composition of EMPs, laying a theoretical foundation for the personalized nutritional achievements of EMP. We also establish the foundation for the further investigation and application of EMPs as novel functional foods and healthy products.

Steady-State Delivery and Chemical Modification of Food Nutrients to Improve Cancer Intervention Ability

Cancer is a crucial global health problem, and prevention is an important strategy to reduce the burden of the disease. Daily diet is the key modifiable risk factor for cancer, and an increasing body of evidence suggests that specific nutrients in foods may have a preventive effect against cancer. This review summarizes the current evidence on the role of nutrients from foods in cancer intervention. It discusses the potential mechanisms of action of various dietary components, including phytochemicals, vitamins, minerals, and fiber. The findings of epidemiological and clinical studies on their association with cancer risk are highlighted. The foods are rich in bioactive compounds such as carotenoids, flavonoids, and ω-3 fatty acids, which have been proven to have anticancer properties. The effects of steady-state delivery and chemical modification of these food's bioactive components on anticancer and intervention are summarized. Future research should focus on identifying the specific bioactive compounds in foods responsible for their intervention effects and exploring the potential synergistic effects of combining different nutrients in foods. Dietary interventions that incorporate multiple nutrients and whole foods may hold promise for reducing the risk of cancer and improving overall health.

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.

Antitumor Activity of Carboxymethyl Pachymaran with Different Molecular Weights Based on Immunomodulatory and Gut Microbiota

Carboxymethyl pachymaran (CMP) was treated via high-temperature and cellulase hydrolysis to obtain HTCMP, HTEC-24, and HTEC-48. The chemical structure and in vivo antitumor activities of the four types of CMPs were investigated. Compared with CMP (787.9 kDa), the molecular weights of HTCMP, HTEC-24, and HTEC-48 were decreased to 429.8, 129.9, and 68.6 kDa, respectively. The viscosities and particle sizes of the CMPs could also decrease with the decline in the molecular weights. All the CMPs showed antitumor abilities, but HTEC-24 exhibited the best activity. In the animal study, when curing the spleen and thymus, CMPs displayed immunomodulatory effects by increasing the secretion of IFN-γ and IL2 in mice. The CMPs also exerted an antitumor ability by regulating the gut microbiota in tumor-bearing mice. Our results established a foundation to develop an antitumor drug with CMP.

Metabolic degradation of polysaccharides from Lentinus edodes by Kupffer cells via the Dectin-1/Syk signaling pathway

It had been shown that lentinan (LNT) was mainly distributed in the liver after intravenous administration. The study aimed to investigate the integrated metabolic processes and mechanisms of LNT in the liver, as these have not been thoroughly explored. In current work, 5-([4,6-dichlorotriazin-2-yl] amino) fluorescein and cyanine 7 were used to label LNT for tracking its metabolic behavior and mechanisms. Near-infrared imaging demonstrated that LNT was captured mainly by the liver. Kupffer cell (KC) depletion reduced LNT liver localization and degradation in BALB/c mice. Moreover, experiments with Dectin-1 siRNA and Dectin-1/Syk signaling pathway inhibitors showed that LNT was mainly taken up by KCs via the Dectin-1/Syk pathway and promoted lysosomal maturation in KCs via this same pathway, which in turn promoted LNT degradation. These empirical findings offer novel insights into the metabolism of LNT in vivo and in vitro, which will facilitate the further application of LNT and other β-glucans.

Targeting mTOR Signaling by Dietary Polysaccharides in Cancer Prevention: Advances and Challenges

Cancer is the most serious problem for public health. Traditional treatments often come with unavoidable side effects. Therefore, the therapeutic effects of natural products with wide sources and low toxicity are attracting more and more attention. Polysaccharides have been shown to have cancer-fighting potential, but the molecular mechanisms remain unclear. The mammalian target of rapamycin (mTOR) pathway has become an attractive target of antitumor therapy research in recent years. The regulation of mTOR pathway not only affects cell proliferation and growth but also has an important effect in tumor metabolism. Recent studies indicate that dietary polysaccharides play a vital role in cancer prevention and treatment by regulating mTOR pathway. Here, the progress in targeting mTOR signaling by dietary polysaccharides in cancer prevention and their molecular mechanisms are systemically summarized. It will promote the understanding of the anticancer effects of polysaccharides and provide reference to investigators of this cutting edge field.

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.

A β-glucan from Aureobasidium pullulans enhanced the antitumor effect with rituximab against SU-DHL-8

β-Glucans affect the immune system and have antitumor activity; therefore, they are being investigated as immunomodulators and chemotherapeutic adjuvants. In this study, we investigated a specific β-glucan, exopolysaccharide (EPS-1) derived from Aureobasidium pullulans (CGMCC 20363), to investigate its impact on the efficacy of rituximab against diffuse large B cell lymphoma (SU-DHL-8 cells) in vitro and in vivo. The results show that compared to rituximab alone, EPS-1 enhanced the inhibition of SU-DHL-8, had antitumor effects in vivo, and improved the response of the immune system of the host. RNA sequencing results reveal that EPS-1 had a chemotactic effect on T cells through the JAK-STAT signaling pathway and recruited immune cells into tumor tissues. EPS-1 also played an antitumor role through the mitochondrial and death receptor Fas-related apoptotic pathways. In summary, EPS-1 may be an effective adjuvant to treat diffuse large B cell lymphoma in combination with rituximab.

Immunomodulatory Properties of Polysaccharides from Lentinula edodes

Lentinula edodes (Berk.) Pegler, also known as shiitake mushroom, is a popular edible macrofungus and a source of numerous bioactive substances with multiple beneficial health effects. L. edodes-derived polysaccharides are the most valuable compounds, with anticancer, antioxidant, antimicrobial, and immunomodulatory properties. It has been demonstrated that their biological activity depends on the extraction method, which affects monosaccharide composition, molecular weight, branching degrees, and helical conformation. In this review, we discuss the immunomodulatory properties of various polysaccharides from L. edodes in animal models and in humans.

Metabolism and Biodegradation of β-Glucan in vivo

The β-Glucans widely exist in plants and edible fungi, and their diverse bioactivities and good physicochemical properties have been widely reported. In addition, β-glucan intravenous injections (such as lentinan and schizophyllan) have been clinically used as immunomodulators and antitumor polysaccharides. However, the pharmacokinetic studies of β-glucans only stay on the level of plasma concentration and biodistribution in vivo, and little is known about their metabolism and degradation in vivo, which severely limits the further application of β-glucans in the field of medicine and biomaterials. The aim of this paper is to explore the metabolism and degradation process of lentinan (as a representative of β-glucans) in vivo by labeling it with water-soluble fluorescein 5-([4, 6-Dichlorotriazin-2-yl]amino)fluorescein (DTAF). Fluorescently labeled lentinan (FLNT) was intravenously administered to rats at a single dose of 8 mg/kg. The degradation of LNT in blood, liver, kidney, and urine was evaluated by the gel permeation chromatography. Our results showed that although LNT could be degraded in blood, liver, kidney, and urine, there were still some prototypes until excreted in urine due to the incomplete degradation of LNT in each step. To the best of our knowledge, this is the first report to comprehensively study LNT metabolic degradation in rats. These results provide an important reference for further exploration and application of LNT and other β-glucans.

Proteins and polysaccharides from vegetative mycelium of medicinal basidiomycete Lentinus edodes display cytotoxicity towards human and animal cancer cell lines

Detection and study of biologically active compounds seems a promising area of research in cancer diagnostics and therapies. The glycoprotein and polysaccharide fractions showing high cytotoxicity towards several human and animal cancer cell lines: A549, Hep-2, HeLa, С6 and SPEV-2 were isolated from basidiomycete Lentinus edodes vegetative mycelium and fruiting body and further characterized. It was found that water-soluble glycoprotein fractions caused the most significant, 70-100% inhibition of metabolic activity of SPЕV-2, А549 and С6 cell lines. The effective concentrations of glycoprotein fractions reducing the viability of cancer cell lines were determined. The protein and subunit composition of fractions was studied; the highly active galactose-specific lectins were found to be present in these fractions. Comparative analysis of transcriptomes of L. edodes vegetative mycelium, fruiting body and primordium revealed the presence of carbohydrate-binding glycoproteins (lectins) specific for each stage of basidiomycete morphogenesis. Histological examination revealed some morphological indicators of immune system activation and the absence of toxic effect on gastro-intestinal mucosa of animals at peroral administration of fungal glycoprotein fractions. Fungal protein and, in particular, lectin preparations derived from L. еdodes vegetative mycelium might be considered as novel prospective tools in cancer diagnostics and therapies.

Local delivery of biocompatible lentinan/chitosan composite for prolonged inhibition of postoperative breast cancer recurrence

Postsurgical localized chemotherapy for breast cancer recurrence (BCR) still faces many problems which dampen researchers' enthusiasm and discounted prognosis. Simple strategies with controllable toxicities are expected to address these hurdles. Lentinan (LNT) has excellent biocompatibility and notable antitumor activity but rather low bioavailability after intravenous or oral administration. Here, a sponge-like LNT/chitosan composite (LNT/CS sponge) was prepared for efficient local delivery to prevent postoperative BCR. The obtained sponges exhibit uniform porosity and sustained release of LNT in vitro and in vivo. Furthermore, the sponges were implanted and showed significant reduction of postsurgical recurrence and suppression of long-term tumor regrowth with favorable biocompatibility in a subcutaneous postsurgical recurrence mouse model. Subsequent studies revealed that LNT can restrain the stemness of breast cancer cells, which may account for the long-term inhibition of tumor relapse. Therefore, LNT/CS sponge has a great potential as a promising alternative for postsurgical BCR.

Beta-Glucans from Fungi: Biological and Health-Promoting Potential in the COVID-19 Pandemic Era

Beta-glucans comprise a group of polysaccharides of natural origin found in bacteria, algae, and plants, e.g., cereal seeds, as well as microfungi and macrofungi (mushrooms), which are characterized by diverse structures and functions. They are known for their metabolic and immunomodulatory properties, including anticancer, antibacterial, and antiviral. Recent reports suggest a potential of beta-glucans in the prevention and treatment of COVID-19. In contrast to β-glucans from other sources, β-glucans from mushrooms are characterized by β-1,3-glucans with short β-1,6-side chains. This structure is recognized by receptors located on the surface of immune cells; thus, mushroom β-glucans have specific immunomodulatory properties and gained BRM (biological response modifier) status. Moreover, mushroom beta-glucans also owe their properties to the formation of triple helix conformation, which is one of the key factors influencing the bioactivity of mushroom beta-glucans. This review summarizes the latest findings on biological and health-promoting potential of mushroom beta-glucans for the treatment of civilization and viral diseases, with particular emphasis on COVID-19.

Lentinan inhibited colon cancer growth by inducing endoplasmic reticulum stress-mediated autophagic cell death and apoptosis

Lentinan (SLNT) has been shown to be directly cytotoxic to cancer cells. However, this direct antitumour effect has not been thoroughly investigated in vivo, and the mechanism remains unclear. We aimed to examine the direct antitumour effect of SLNT on human colon cancer and the mechanism in vivo and in vitro. SLNT significantly inhibited tumour growth and induced autophagy and endoplasmic reticulum stress (ERS) in HT-29 cells and tumour-bearing nonobese diabetic (NOD)/severe combined immunodeficiency (SCID) mice. Experiments with the autophagy inhibitors chloroquine (CQ) and 3-methyladenine (3-MA) showed that autophagy facilitated the antitumour effect of SLNT. Moreover, ERS was identified as the common upstream regulator of SLNT-induced increases in Ca2+concentrations, autophagy and apoptosis by using ERS inhibitors. In summary, our study demonstrated that SLNT exerted direct antitumour effects on human colon cancer via ERS-mediated autophagy and apoptosis, providing a novel understanding of SLNT as an anti-colon cancer therapy.

Plant/algal polysaccharides extracted by microwave: A review on hypoglycemic, hypolipidemic, prebiotic, and immune-stimulatory effect

Microwave-assisted extraction (MAE) is an emerging technology to obtain polysaccharides with an extensive spectrum of biological characteristics. In this study, the hypoglycemic, hypolipidemic, prebiotic, and immunomodulatory (e.g., antiinflammatory, anticoagulant, and phagocytic) effects of algal- and plant-derived polysaccharides rich in glucose, galactose, and mannose using MAE were comprehensively discussed. The in vitro and in vivo results showed that these bioactive macromolecules with the low digestibility rate could effectively alleviate the fatty acid-induced lipotoxicity, acute hemolysis, and dyslipidemia status. The optimally extracted glucomannan- and glucogalactan-containing polysaccharides revealed significant antidiabetic effects through inhibiting α-amylase and α-glucosidase, improving dynamic insulin sensitivity and secretion, and promoting pancreatic β-cell proliferation. These bioactive macromolecules as prebiotics not only improve the digestibility in gastrointestinal tract but also reduce the survival rate of pathogens and tumor cells by activating macrophages and producing pro-inflammatory biomarkers and cytokines. They can effectively prevent gastrointestinal disorders and microbial infections without any toxicity.

Mechanism of Lentinan Intestinal Absorption: Clathrin-Mediated Endocytosis and Macropinocytosis

Lentinan (LNT), a typical triple helix β-glucan extracted from Lentinus edodes, has been widely used as a functional food and an orally administered drug. However, its oral pharmacokinetics has been rarely reported. The aim of this work is to systematically study the pharmacokinetics and intestinal absorption mechanism of LNT after oral administration. Radioactive 99m-technetium (^99mTc) was introduced to label LNT to determine the plasma concentration, tissue distribution, and excretion of the β-glucan in rats after oral administration. The results confirmed the absorption of LNT, with the maximal plasma concentration reached at 1 h. 5-([4,6-Dichlorotriazin-2-yl]amino)fluorescein (DTAF) was used to label LNT to explore the absorption mechanism of LNT, utilizing both a Ussing chamber and a monolayer of Caco-2 cells. These transport assays showed that LNT could penetrate through the intestine and epithelial monolayer, which was mediated by macropinocytosis and clathrin-mediated endocytosis. These findings provide a pharmacokinetic reference for LNT and help provide a greater understanding of the absorption of β-glucans in general.

Biological activities of Pleurotus spp. polysaccharides: A review

Mushrooms are consumed for their nutrients and therapeutic bioactive compounds and are used medicinally in Chinese and Japanese medicine traditions since time immemorial. Members of the genus Pleurotus form a heterogeneous group of edible species with outstanding nutritional profiles rich in fiber, vitamins (thiamine, riboflavin, ascorbic acid, ergosterine, and niacin), micro and macro-elements (phosphorus and iron), and carbohydrates. Pleurotus is one of the most diversified medicinal and edible mushrooms related to the composition of chemical structures such as polysaccharides, glycoproteins, and secondary metabolites such as alkaloids and betalains. The cultivation of Pleurotus spp. on lignocellulosic wastes represents one of the most economically and cost-effective organic recycling processes, especially for the utilization of different feasible and cheap recyclable residues. Also, several Pleurotus spp. have the ability to remove phenolic compounds from wastewater with the action of phenoloxidase activity. Here, we have reviewed the chemistry of such polysaccharides and their reported biological activities, namely, anti-inflammatory, immunomodulatory, anti-diabetic, anti-tumor, antioxidant, etc. The mechanism of action and effects of novel polysaccharides extracted from various species of Pleurotus have been studied. The current study will be beneficial for guiding future research projects on the above concept and investigating more deeply the health of human beings. PRACTICAL APPLICATIONS: Mushrooms are one of the most delicious foods around the globe and have many medicinal properties for decades. Various Pleurotus species have been in focus in recent years because of their palatability and medicinal importance too. It contains many bioactive compounds among which polysaccharides are valued to a great extent. Many biological activities are exerted by polysaccharides derived from the Pleurotus spp., namely, anti-tumor, antioxidant, and many more. They are responsible for significant physiological responses in animals, animal-alternative in vitro models, and humans. Their important physicochemical characteristics benefit their use in the food industry as well. So, the biological activities of these Pleurotus spp. polysaccharides will provide an insight to develop Pleurotus spp. as functional foods, because of their nutritional value and presence of bioactive components.

Recent advances in polysaccharides from Lentinus edodes (Berk.): Isolation, structures and bioactivities

Lentinus edodes, an important edible mushroom cultivated in East Asia for thousands of years, has been widely used as food and medicinal ingredient worldwide. Modern phytochemistry studies have demonstrated that L. edodes is very rich in bioactive polysaccharides, especially the β-glucans. Over the past two decades, the isolation, chemical properties, and bioactivities of polysaccharides from fruiting bodies, mycelium and fermentation broth of L. edodes have been drawing much attention from scholars around the world. It has been demonstrated that L. edodes polysaccharides possess various remarkable biological activities, including anti-oxidant, anti-tumor, anti-aging, anti-inflammation, immunomodulatory, antiviral, and hepatoprotection effects. This review summarizes the recent development of polysaccharides from L. edodes including the isolation methods, structural features, bioactivities and mechanisms, and their structure-activity relationship, which can provide useful research underpinnings and update information for their further application as therapeutic agents and functional foods.

Triple-helix polysaccharides: Formation mechanisms and analytical methods

Triple helix conformation of polysaccharides is generally believed to be associated with their biological activities. However, the formation mechanisms and analytical methods for the triple helix polysaccharides, to our best knowledge, have not been systematically investigated. This article reviews specifically the literature on the formation and characterization of triple-helix polysaccharides. The formation mechanisms and related structural-conformation-bioactivity relationships are discussed; various analytical methods for characterizing triple-helix polysaccharides are summarized. This review devotes to a better understanding of the formation of polysaccharides based triple-helix structure and related analytical methods. These could provide some insights and inspirations for their applications in both food and pharmaceutical industries.

Challenges and Perspectives of Standard Therapy and Drug Development in High-Grade Gliomas

Despite their low incidence rate globally, high-grade gliomas (HGG) remain a fatal primary brain tumor. The recommended therapy often is incapable of resecting the tumor entirely and exclusively targeting the tumor leads to tumor recurrence and dismal prognosis. Additionally, many HGG patients are not well suited for standard therapy and instead, subjected to a palliative approach. HGG tumors are highly infiltrative and the complex tumor microenvironment as well as high tumor heterogeneity often poses the main challenges towards the standard treatment. Therefore, a one-fit-approach may not be suitable for HGG management. Thus, a multimodal approach of standard therapy with immunotherapy, nanomedicine, repurposing of older drugs, use of phytochemicals, and precision medicine may be more advantageous than a single treatment model. This multimodal approach considers the environmental and genetic factors which could affect the patient's response to therapy, thus improving their outcome. This review discusses the current views and advances in potential HGG therapeutic approaches and, aims to bridge the existing knowledge gap that will assist in overcoming challenges in HGG.

Molecular dynamics simulation of lentinan and its interaction with the innate receptor dectin-1

Lentinan, a β-1,3-D-glucan, is clinically used as an immune enhancement drug for tumor therapy. Dectin-1 is a cell-surface immune receptor, which plays an important role in immunological defense against fungal pathogens and β-glucan-mediated immune modulation. Herein we attempted to study the advanced structure of lentinan and how lentinan interacts with dectin-1 for its immune enhancement effect. We firstly used MD simulation and rigid macromolecule docking, combining some spectral techniques, to uncover the complex 3D conformation of a typical polysaccharide - lentinan, and the detailed interaction mode of lentinan with dectin-1. We proved by computational simulation that lentinan can maintain its triple-helix through hydrogen network and disclosed some structural properties of lentinan. We also characterized the affinity of lentinan to dectin-1 by LSPR and binding free energy calculation, and we found out that hydrogen bonds and CH-π interaction are the major contributors for lentinan's binding to dectin-1. Besides, after bound with lentinan, dectin-1 might surprisingly go through a conformational change. In summary, our work provided insights into lentinan's advanced structure and β-glucan recognition by dectin-1.

Lentinan Inhibited the Activation of Th2 Cells in Allergic Mice by Reducing the Amplitude of Changes in Biological Rhythm

INTRODUCTION

Biological rhythm is inextricably linked to the physiological mechanisms of allergic diseases, but the exact mechanisms are still poorly understood. Clinical studies have reported rhythmic fluctuations in allergic diseases. The search for natural and harmless active ingredients based on biological rhythm with which to regulate allergic diseases is essential for the control of food allergy.

METHODS

In this study, mice were treated at different time points to determine the link between the severity of allergic reactions and the circadian clock genes. The mice were treated with lentinan, either continuously or discontinuously, to assess their clinical symptoms, vascular permeability, immune cells, cytokines, and clock genes. Specifically, rat basophilic leukemia (RBL-2H3) cells were treated with lentinan and the rhythmic changes of cell degranulation were measured.

RESULTS

The results in different models showed that the allergic reactions in mice treated at different time points were significantly different and thus related to fluctuations in biological rhythm. Treatment with lentinan was found to reduce the amplitude of changes in the clock genes, such as the activation of Per and Cry proteins in allergic mice, as well as to regulate biological rhythm in cells, inhibit the activation of Th2 cells, and alleviate allergic reactions. Furthermore, lentinan changed the rhythm of degranulation in RBL-2H3 cells.

CONCLUSION

Lentinan was, therefore, determined to successfully alleviate allergic reactions by reducing the amplitude of changes in the body's biological rhythm, inhibiting the activation of Th2 cells, and affecting the immune microenvironment.

Phenolic acid bound arabinoxylans extracted from Little and Kodo millets modulate immune system mediators and pathways in RAW 264.7 cells

The immunomodulating effect of Phenolic acid bound arabinoxylans (PCA-AXs) extracted from Little (PCA-AX-L) and Kodo (PCA-AX-K) millet seeds in RAW 264.7 cells were investigated. The PCA-AXs were extracted from millets and their chemical characterization were carried out by GC-MS, HPLC, and FT-IR. The immunomodulatory effect of PCA-AXs in RAW 264.7 cells were investigated by estimating ROS, NO, and cytokines TNF-α, IL-1β, IL-6, and evaluation of molecular mechanism by q-PCR & western blotting techniques. The xylose: arabinose ratio of PCA-AX-L and PCA-AX-K were 1.48:1.0 and 2.26:1.0, respectively. The phenolic acids content was higher in PCA-AX-K than PCA-AX-L determined by HPLC. FT-IR analysis confirms the presence of α-glucosidic linkage with the degree of substitution of xylan backbone by arabinose residues. The evaluation of immunomodulating effect of PCA-AXs revealed that the PCA-AX-L-treated cells showed higher release of NO, ROS and cytokines than PCA-AX-K-treated cells. The mRNA expressions of TNF-α, iNOS and COX-2 were upregulated by PCA-AX-L and downregulated by PCA-AX-K in dose-dependent manner. Furthermore, in western blotting, the ERK and NF-κB were found to be activated by PCA-AX-L and inhibited by PCA-AX-K. Our findings suggest that the high branched arabinoxylans of PCA-AX-L could modulate the immune response in RAW 264.7 cells through activation of ERK and NF-κB signaling pathways and acts as an immunostimulant. The higher phenolic content in PCA-AX-K could modulate the immune response by downregulation of ERK and NF-κB signaling pathways and thus, it could act as an immunomodulator. PRACTICAL APPLICATIONS: Millets are the richest source of arabinoxylans in which they are known to be bound with phenolic acids (PCA-AX). Arabinoxylans derived from rice and wheat is known immunomodulators. This study was focused to evaluate the immunomodulatory property of PCA-AX derived from two different millets little and kodo. The study results clearly indicated the immune stimulatory action of PCA-AX-L and immunomodulatory action of PCA-AX-K. The explored mechanism indicated that the PCA-AXs modulate NF-κB & ERK pathways for their immunomodulatory action.

Apoptosis induction activity of polysaccharide from Lentinus edodes in H22-bearing mice through ROS-mediated mitochondrial pathway and inhibition of tubulin polymerization

Background

Lentinus edodes is a medicinal mushroom widely used in Asian countries for protecting people against some types of cancer and other diseases.

Objective

The objective of the present study was to investigate the direct antiproliferation activity and the antitumor mechanisms of water-extracted polysaccharide (WEP1) purified from L. edodes in H22 cells and H22-bearing mice.

Design

The extraction, isolation, purification, and structure determination of the water-soluted L. edodes polysaccharide WEP1 were performed. The growth inhibitory effects of WEP1 on H22 cells and H22-bearing mice were determined by 3-(4,5-Dimethylthiazol-2-Yl)-2,5-Diphenyltetrazolium Bromide (MTT) method and animal studies. Flow cytometry, scanning electron microscopy, and laser scanning confocal microscopy were used to observe the morphological characteristics of apoptotic cells. The levels of intracellular reactive oxygen species (ROS) were detected by flow cytometry using 2',7'-dichlorofluorescein-3',6'-diacetate (DCFH-DA). Western blot was used to determine the expressions of cell cycle proteins and apoptosis-related proteins.

Results

Results showed that WEP1 with a molecular weight of 662.1 kDa exhibited direct antiproliferation activity on H22 cells in a dose-dependent manner. In vivo, WEP1 significantly inhibited the growth of tumor at different doses (50, 100, and 200 mg/kg) and the inhibition rates were 28.27, 35.17, and 51.72%, respectively. Furthermore, morphological changes of apoptosis and ROS overproduction were observed in H22 cells by WEP1 treatment. Cell cycle assay and western blot analyses indicated that the apoptosis induction activity of WEP1 was associated with arresting cell cycle at G2/M phase and activating mitochondrial-apoptotic pathway. Besides, WEP1 disrupted the microtubule network accompanied by alteration of cellular morphology.

Conclusion

Results suggested that the antitumor mechanisms of WEP1 might be related to arresting cell cycle at G2/M phase, inhibiting tubulin polymerization and inducing mitochondrial apoptosis. Therefore, WEP1 possibly could be used as a promising functional food for preventing or treating liver cancer.

Structural characterization and prebiotic potential of an acidic polysaccharide from Imperial Chrysanthemum

A novel water-soluble polysaccharide, named ICP-1, was isolated and purified by Sephadex G-200 after extracting the crude polysaccharide (ICP) from Imperial Chrysanthemum. The structural characterization of ICP-1 was determined by physical and chemical methods, FT-IR, NMR, SEM, HPGPC, periodate oxidation, Smith degradation, methylation and Congo red test. Then, acid production and proliferation of lactic acid bacteria and the tolerance tests of simulated gastrointestinal fluid were measured to investigate the activity of prebiotic potential. The results showed that ICP-1 was an acidic hetero-polysaccharide with an average molecular weight of 2.98 × 10³ kDa and a specific optical rotation of +155°. The glycosyl residues of ICP-1 were composed of (1→), (1→4) and (1→6) glucose, (1→5) arabinose, (1→4) galacturonic acid and (1→3,6) mannose. Besides, ICP-1 can speed up the acid production of lactic acid bacteria and promote the growth and proliferation of lactic acid bacteria effectively.

Extraction and structural analysis of Angelica sinensis polysaccharide with low molecular weight and its lipid-lowering effect on nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is one of the prevalent and typical chronic liver diseases. In this study, we extracted a novel Angelica sinensis polysaccharide (ASP) with low molecular weight (MW) of 3.2 kDa through optimized "one-step" purification process. The major monosaccharide components of ASP were mannose, rhamnose, glucuronic acid, galactose, arabinose, and xylose with weight ratio of 0.23:0.17:14.41:0.39:1.68:0.87, respectively. Herein, "small" ASP could serve as an effective therapeutic option for NAFLD both in free fatty acid-induced L02 models and in high-fat diet-induced mice models. Results revealed that low MW ASP dose-dependently decreased TG, TC in vitro and TG, TC, ALT, HDL-C, and LDL-C in vivo. Oil Red O-positive area and Nile red fluorescence intensity decreased in ASP treatment groups both in vitro and in vivo which suggested ASP could reduce lipid accumulation and fatty regeneration. Hematoxylin-eosin staining results shown a decrease in hepatocytes ballooning indicating that ASP could ameliorate liver lipid degeneration. Briefly, a novel polysaccharide with low MW was successfully obtained which can prospectively act as NAFLD therapy.

Recent Advances in Chain Conformation and Bioactivities of Triple-Helix Polysaccharides

Natural polysaccharides derived from renewable biomass sources are regarded as environmentally friendly and sustainable polymers. As the third most abundant biomacromolecule in nature, after proteins and nucleic acids, polysaccharides are also closely related with many different life activities. In particular, β-glucans are one of the most widely reported bioactive polysaccharides and are usually considered as biological response modifiers. Among them, β-glucans with triple-helix conformation have been the hottest and most well-researched polysaccharides at present, especially lentinan and schizophyllan, which are clinically used as cancer therapies in some Asian countries. Thus, creation of these active triple-helix polysaccharides is beneficial to the research and development of sustainable "green" biopolymers in the fields of food and life sciences. Therefore, full fundamental research of triple-helix polysaccharides is essential to discover more applications for polysaccharides. In this Review, the recent research progress of chain conformations, bioactivities, and structure-function relationships of triple-helix β-glucans is summarized. The main contents include the characterization methods of the macromolecular conformation, proof of triple helices, bioactivities, and structure-function relationships. We believe that the governments, enterprises, universities, and institutes dealing with the survival and health of human beings can expect the development of natural bioproducts in the future. Hence, a deep understanding of β-glucans with triple-helix chain conformation is necessary for application of natural medicines and biologics for a sustainable world.

Evaluation of bioactive compounds and antioxidant capacity of edible feijoa (Acca sellowiana (O. Berg) Burret) flower extracts

Abstract

The research aimed to evaluate the polyphenolic composition and the antioxidant capacity of edible extracts of feijoa (Acca sellowiana (O. Berg) Burret) flowers. Phenolic compounds of whole feijoa flower (FM), feijoa petals (PM) and feijoa petals juice (PJ) were identified by high-performance liquid chromatography coupled with electrospray mass spectrometry and quantified by liquid chromatography coupled with ultraviolet/visible detection. Moreover, the total polyphenol (TP) content was measured spectrophotometrically and the antioxidant capacities of the extracts were evaluated by FRAP, CUPRAC, DPPH^·, and ABTS^·+ assays. The FM showed TP content (395.14 ± 7.91 mg GAE/L) higher than PM and PJ, and exhibited better antioxidant capacities. FM extracts were characterized by the high content of anthocyanins (115.3 ± 3.6 mg/L), flavonols (42.9 ± 3.3 mg/L) and the presence of ellagic acid (7.9 ± 0.2 mg/L) and other galloyltannins. In addition, cyanidin-3-O-glucoside and apigenin were detected in all the three extracts. The present study provided an overview on particular bioactive compounds that characterise different parts of edible feijoa flowers. Among the latter, FM proved to be the most suitable for exploitation in the food and health manufactory.

Graphic abstract

Chemical characterization and immunostimulatory activity of phenolic acid bound arabinoxylans derived from foxtail and barnyard millets

The chemical characterization and evaluation of immunostimulating effect of phenolic acid bound arabinoxylan (PA-AXs) isolated from barnyard (PA-AX-B) and foxtail (PA-AX-F) millets were performed. The sugar composition analysis and bound phenolic acids' (caffeic acid, p-coumaric acid, and ferulic acid) content of PA-AXs were examined by gas chromatography and mass spectroscopy (GC-MS) and high performance liquid chromatography (HPLC), respectively. The immunostimulatory activity of PA-AXs was evaluated by studying the effect of PA-AXs on the release of nitric oxide (NO), ROS, and cytokine (TNF-α, IL-1β, and IL-6) in RAW 264.7 murine macrophage cells. The GC-MS results revealed the xylose: arabinose ratio of PA-AX-F and PA-AX-B as 1.96:1.0 and 1.64:1.0, respectively. In HPLC analysis, PA-AX-B showed higher phenolic acid content than PA-AX-F. In RAW 264.7 cells, immunostimulatory activity was established by its increased release of NO, ROS, and cytokine (TNF-α, IL-1β, and IL-6) in a dose-dependent manner. Both PA-AX-B and PA-AX-F exhibited significant immunostimulation in in vitro studies. PRACTICAL APPLICATIONS: Millets are known for the higher content of phenolic acid bound arabinoxylans (PA-AX). The composition of PA-AX varies with different types of millets. In general, rice bran and wheat arabinoxylans are well reported to have significant immunostimulatory and antitumor properties. The bound ferulic acid with arabinoxylan isolated from finger millet bran also possesses immunostimulatory property. As the millets grains, foxtail and barnyard are also rich in PA-AXs, the present study was focused to evaluate the immunostimulatory property of PA-AX derived from two different millets. The study results indicated the immune stimulatory action of millet PA-AX's and thus the purified PA-AX can be explored further to identify the mechanism of action with respect to its immune stimulation property.

Structural Characterization and Immunomodulatory Activity of a Polysaccharide from Eurycoma longifolia

A polysaccharide, Ali-1, was isolated from the roots of Eurycoma longifolia, a popular traditional medicinal herb in Malaysia. The structure of Ali-1 was characterized by monosaccharide, methylation, and NMR data analyses. The average molecular weight of Ali-1 is 14.3 ku, and it is composed of arabinose (14.31%), xylose (57.69%), galacturonic acid (13.03%), and glucuronic acid (14.86%). The main chain comprises (1→4)-linked xylose residues. It has branch points in the main chain; (1→2,4)-linked xylose residues, 1,2-linked glucuronic acid residues, and 1,2-linked arabinose residues form the branches, and the branches are terminated with T-linked galacturonic acid residues and T-linked arabinose residues. Ali-1 significantly improves the pinocytic and phagocytic abilities of RAW264.7 cells and facilitates cytokine secretion according to an immunostimulation assay. These results demonstrate that Ali-1 has potential as a functional supplement for people with compromised immune systems.

A sensitive and rapid radiolabelling method for the in vivo pharmacokinetic study of lentinan

The aim of this study is to establish a rapid and sensitive method for detecting lentinan (LNT) in biosamples and to evaluate the pharmacokinetics of LNT in mice and rats. A diethylenetriaminepentaacetic acid (DTPA) derivative of LNT (DTPA-LNT) was synthesized first to allow labelling with 99m-technetium (99mTc). After purification and identification, 99mTc-DTPA-LNT was intravenously administered to mice (2 mg kg-1) and rats at different doses (0.5, 2 and 8 mg kg-1). The results showed that the 99mTc-labelling method was suitable for the quantification of the LNT concentration in biological samples, with satisfactory linearity (r2 > 0.998), precision (<7%), accuracy (95.01-104.51%) and total recovery (∼90%). The blood concentration-time profiles of 99mTc-DTPA-LNT were consistent with the two-compartment model and showed a rapid distribution phase and a slow elimination, and no significant difference in the blood level of LNT was found among the tested doses (0.5, 2 and 8 mg kg-1). LNT was predominantly incorporated into the liver and spleen, and there was a small amount of aggregation in the bile, kidneys, lungs and stomach. Approximately 40% of the administered radioactivity was detected in urine and faeces within 24 h post-dosing. In addition, SPECT imaging of 99mTc-DTPA-LNT was performed to visually reveal the pharmacokinetic characteristics of LNT. These findings provide a reference for further study and for use of LNT and other β-glucans.