Studies on structural properties and immune-enhancing activities of glycomannans from Schizophyllum commune

Effect of low-frequency alternating magnetic field on exopolysaccharide production and antioxidant capacity of Pleurotus citrinopileatus by submerged fermentation

The objective of this study was to investigate the effect of low-frequency alternating magnetic field (LF-AMF) on the production of extracellular polysaccharide (EPS) by submerged fermentation of Pleurotus citrinopileatus. The fermentation conditions optimized by the central composite design method were as follows: fermentation time of 6.18 days, temperature of 28.28 °C, shaking speed of 149.04 r/min, and inoculum amount of 8.43%. Under these conditions, a LF-AMF was applied to the submerged fermentation of P. citrinopileatus. When the intensity of LF-AMF was 40 Gs, the initial intervention time was 24 h after inoculation, and the treatment time was 6 h at one time, the mycelial biomass of P. citrinopileatus increased by 11.30%, and the EPS yield increased by 23.09% compared with the fermentation without LF-AMF treatment. The morphology of mycelium after LF-AMF treatment was observed by scanning electron microscopy. It was found that the surface of mycelium was wrinkled, and the structure of mycelium was loose, which might be more conducive to the production of EPS. Mycelium diameter decreased, and ATPase activity increased, indicating that LF-AMF had a positive effect on the production of EPS by P. citrinopileatus fermentation. Moreover, LF-AMF could improve the permeability of the mycelial cell membrane, facilitate the exchange of intracellular and extracellular substances, and increase the metabolic capacity of P. citrinopileatus. In vitro antioxidant test of EPS showed that LF-AMF treatment also improved its antioxidant capacity.

A polysaccharide PRCP from Rosa cymosa Tratt fruit: Structural characteristics and immunomodulatory effects via MAPK pathway modulation in vitro

The Rosa cymosa Tratt, an herbal plant from the Rosaceae family, has historically been valued in China for its medicinal and edible properties. In this study, a novel polysaccharide from R. cymosa fruit, termed PRCP (purified R. cymosa polysaccharide), was isolated using water extraction, decolorization, deproteinization, and ion-exchange chromatography. The structural characteristics of PRCP were investigated using monosaccharide composition analysis, methylation, GPC, FTIR, CD, and NMR spectroscopy. The immunomodulatory effect and potential mechanism of PRCP were evaluated in vitro using a macrophage cell model. Results indicated that PRCP (37.28 kDa) is a highly branched polysaccharide (72.61 %) primarily composed of arabinogalactan, rhamnogalacturonan, and galactoglucan domains with 13 types of glycosidic linkage fragments. Furthermore, PRCP appears to modulate immunomodulatory effects by influencing the phosphorylation of P38 and JNK proteins in the MAPK pathway. Collectively, these findings highlight the potential of PRCP as a promising natural functional food ingredient for immunostimulation.

An alkali-extracted neutral heteropolysaccharide from Phellinus nigricans used as an immunopotentiator in immunosuppressed mice by activating macrophages

A neutral heteropolysaccharide (PNANb) was isolated with alkali (0.1 M NaOH) from mycelia of Phellinus nigricans, and the structure, immunostimulating activity and some of the underlying molecular mechanisms of action of PNANb were explored in the current study. PNANb (14.95 kDa) predominantly consisted of Gal, Glc, and Man with minor Fuc. GC-MS and NMR analyses indicated that the backbone of PNANb was mainly composed of 6-α-Galp, 2,6-α-Galp with minor 3,6-β-Glcp, which was substituted with complex side chains at C-2 of 2,6-α-Galp and C-3 of 3,6-β-Glcp. Notably, PNANb (50 or 100 mg/kg) possessed immunoprotective effects in cyclophosphamide (Cy)-induced immunosuppressed C57BL/6 mice, which was supported by evidence including the enhancement of spleen and thymus indices, levels of serum immunoglobulins (IgG, IgM) and cytokines (IFN-γ, IL-2, IL-4, IL-10), and macrophage activity. However, the immunostimulation effects of PNANb were decreased when macrophages were depleted, underscoring the essential role of macrophages in the beneficial effects of PNANb in Cy-induced immunosuppressed mice. Further investigations in vitro indicated that PNANb activated macrophages through MAPK/NF-κB signaling pathways mediated by Toll-like receptor 4. Therefore, PNANb can serve as a prospective immunopotentiator in immunosuppression.

Fermentation enrichment, structural characterization and immunostimulatory effects of β-glucan from Quinoa

We developed an efficient mixed-strain co-fermentation method to increase the yield of quinoa β-glucan (Q+). Using a 1:1 mass ratio of highly active dry yeast and Streptococcus thermophilus, solid-to-liquid ratio of 1:12 (g/mL), inoculum size of 3.8 % (mass fraction), fermentation at 32 °C for 27 h, we achieved the highest β-glucan yield of (11.13 ± 0.80)%, representing remarkable 100.18 % increase in yield compared to quinoa β-glucan(Q-) extracted using hot water. The structure of Q+ and Q- were confirmed through Fourier Transform Infrared (FTIR) and Nuclear Magnetic Resonance (NMR) spectroscopies. Q+ contained 41.66 % β-glucan, 3.93 % protein, 2.12 % uronic acid; Q- contained 37.21 % β-glucan, 11.49 % protein, and 1.73 % uronic acid. The average molecular weight of Q+(75.37 kDa) was lower than that of Q- (94.47 kDa). Both Q+ and Q- promote RAW264.7 cell proliferation without displaying toxicity. They stimulate RAW264.7 cells through the NF-κB and MAPK signaling pathways, primarily inducing NO and pro-inflammatory cytokines by upregulating CD40 expression. Notably, Q+ exhibited stronger immunostimulatory activity compared to Q-. In summary, the fermentation enrichment method yields higher content of quinoa β-glucan with increased purity and stronger immunostimulatory properties. Further study of its bioimmunological activity and structure-activity relationship may contribute to the development of new immunostimulants.

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.

Anti-Inflammatory Sesquiterpenes from Fruiting Bodies of Schizophyllum commune

Schizophyllum commune, a fleshy fungus, is an important medicinal and food-homologous mushroom in China. In this work, eight undescribed sesquiterpenes schizomycins A-H (1-8) and one new meroterpenoid schizomycin I (9) together with three known analogues (10-12) were isolated from fruiting bodies of S. commune. Their planar structures were established by extensive spectroscopic and mass spectrometric data. The absolute configurations of compounds 1, 2, and 4 were determined by single crystal X-ray diffraction, and compounds 3 and 5-9 were confirmed by electronic circular dichroism calculations. Anti-inflammatory activities of all isolated compounds were evaluated for their inhibitory effects on IL-6 and IL-1β production in RAW 264.7 cells. Among them, compound 7 exhibited significant IL-6 inhibitory activity with an IC50 value of 3.6 μM. The results of molecular docking showed that compound 7 interacts with amino acid residues (Gly117, Lys118, Asp120, Thr166, and Try168) of the IL-6 receptor protein through hydrogen bonding.

Corrigendum: Immunomodulatory function and anti-tumor mechanism of natural polysaccharides: a review

[This corrects the article DOI: 10.3389/fimmu.2023.1147641.].

Cold Alkali-Extractable Antioxidative Polysaccharide from Russula pseudocyanoxantha (Agaricomycetes), a Novel Mushroom, Stimulates Immune Responses in RAW264.7 Cells by Regulating the TLR/NF-κB Pathway

In our previous study, we have established Russula pseudocyanoxantha as a unique species, playing a crucial role in indigenous diets through ages. The research also brought attention to bioactive potential of polysaccharide fraction extracted from the unexplored food using hot water. However, residue of the conventional process still contains therapeutic biopolymers that could further be utilized for pharmacological purposes instead of being discarded. Therefore, the current study aims to valorize the solid remnants, contributing to a deeper understanding of the novel taxon. Subsequently, the leftover was treated with cold alkali, leading to the preparation of a high-yield fraction (RP-CAP). Chemical characterization through FT-IR, GC-MS, HPTLC, and spectroscopy demonstrated presence of several monomers in the carbohydrate backbone, predominantly composed of β-glucan. Furthermore, GPC chromatogram indicated presence of a homogeneous polymer with molecular weight of ~ 129.28 kDa. Subsequently, potent antioxidant activity was noted in terms of radical scavenging (O2·-, OH·, DPPH· and ABTS·+), chelating ability, reducing power and total antioxidant activity where EC50 values ranged from 472-3600 μg/mL. Strong immune-boosting effect was also evident, as the biopolymers stimulated murine macrophage cell proliferation, phagocytic activity, pseudopod formation, and NO as well as ROS synthesis particularly at the concentration of 100 μg/mL. In-depth analysis through RT-PCR revealed that the fraction stimulated synthesis of several inflammatory mediators, elucidating the mode of action through TLR/ NF-κB pathway. Therefore, the findings collectively suggest that RP-CAP possesses great potential to serve as a healthimproving component in functional food and pharmaceutical sectors.

Unlocking the benefits of split gill mushroom: Chemical analysis and prebiotic properties of schizophyllan extract

The edible split gill mushroom is considered both a nutritive and therapeutic superfood, as well as rich in schizophyllan and protein. Prebiotic properties and other biological effects distinguish the schizophyllan (β-glucan). Thus, this research investigates the identity of the mushroom strain, the nutritional composition of this mushroom, and the schizophyllan extract for further analysis, including its prebiotic activity and so on. The experimental results revealed that this mushroom was identified as Schizophyllum commune, comprising more excellent carbohydrates, protein, crude fiber, lower fat, and no heavy metal detection. Moreover, this extract consisted of pharmaceutical hydrophobin (14.0-18.5 kDa), lectin protein (21-35 kDa), bioactive purpurin or red pigment, including the prebiotic β-glucan stimulating the proliferation of probiotic bacteria isolated from yogurt. Therefore, both S. commune and the schizophyllan extract can be used as a prebiotic candidate, functional food, and nutraceutical product.

Structural properties and immune-enhancing activities of galactan isolated from red seaweed Grateloupia filicina

A water-soluble polysaccharide (GFP) was isolated from Grateloupia filicina and fractionated using a DEAE Sepharose Fast Flow column to evaluate immunostimulatory activity. Carbohydrates (62.0%-68.4%) and sulfates (29.3%-34.3%) were the major components of GFP and its fractions (GFP-1 and GFP-2), with relatively lower levels of proteins (4.5%-15.4%) and uronic acid (1.4%-3.9%). The average molecular weight (Mw ) for GFP and its fractions was calculated between 98.2%-243.7 kDa. The polysaccharides were composed of galactose (62.1%-87.2%), glucose (4.5%-33.2%), xylose (3.1%-5.3%), mannose (1.4%-2.2%), rhamnose (1.2%-2.0%), and arabinose (0.9%-1.7%) units connected through →3)-Galp-(1→, →4)-Galp-(1→, →2)-Galp-(1→, →6)-Galp-(1→, →3,4)-Galp -(1→, →3,6)-Galp-(1→, →4,6)-Galp-(1→, →3,4,6)-Galp-(1→, →2,3)-Galp-(1→, →2,4)-Galp-(1→, →4)-Glcp-(1→, →6)-Glcp-(1→ and →4,6)-Glcp-(1→residues. The isolated polysaccharides effectively induced RAW264.7 murine macrophages by releasing nitric oxide (NO) and various cytokines via nuclear factor kappa light chain enhancer of activated B cells (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways. Further, the expression of toll-like receptor-2 (TLR-2) and TLR-4 in RAW264.7 cells indicated their activation through TLR-2 and TLR-4 binding receptors. Among the polysaccharides, GFP-1 highly stimulated the activation of RAW264.7 cells, which was mainly constituted of (→1) terminal-D-galactopyranosyl, (1→3)-linked-ᴅ-galactopyranosyl, (1→4)-linked-ᴅ-galactopyranosyl and (1→3,4) -linked-ᴅ-galactopyranosyl residues. These findings demonstrate that GFP-1 from G. filicina are effective at stimulating the immune system and this warrants further investigation to determine potential biomedical applications.

Effect of Steaming and Microwave Heating on Taste of Clear Soup with Split-Gill Mushroom Powder

Salt is widely overconsumed. Among the strategies used in low-salt foods, the addition of flavor enhancers to improve saltiness perception through an umami taste is a viable and promising technique. This study investigated using split-gill mushroom (SGM) powder containing umami taste to increase saltiness in a clear soup for two different heating conditions: steaming under high pressure and microwave heating. According to the E-tongue results, the addition of 0.2-0.8% SGM produced a different taste in the soup compared to the addition of salt, and the addition of 0.2-0.8% SGM yielded a similar taste to the addition of 0.4-0.6% MSG in a plain, clear soup. In flavored soup, SGM at a high concentration had a taste-enhancing impact comparable to 0.4% MSG, whereas SGM at a low concentration had no taste-enhancing effect. The flavored soups containing 0.4 or 0.8% SGM consisted of two umami 5'-nucleotides: adenosine 5'-monophosphate (5'-AMP) and guanosine 5'-monophosphate (5'-GMP); however, inosine 5'-monophosphate (5'-IMP) was not detected. The major umami amino acids were glutamic acid, aspartic acid, and arginine. Microwave heating increased the salinity and total nucleotides and could maintain the umami amino acids, whereas aspartic acid (one of the umami amino acids) was reduced by 8.23% after steaming under high pressure. Thus, after microwave heating and steaming under high pressure, the equivalent umami concentration was reduced by 43.11 and 44.53%, respectively. In conclusion, the addition of SGM and volumetric heating using microwaves could be an alternative method for reducing the amount of salt in soup by increasing the umami taste intensity and salinity.

Immunomodulatory function and anti-tumor mechanism of natural polysaccharides: A review

Polysaccharides extracted from natural resources have attracted extensive attention in biomedical research and pharmaceutical fields, due to their medical values in anti-tumor, immunomodulation, drug delivery, and many other aspects. At present, a variety of natural polysaccharides have been developed as adjuvant drugs in clinical application. Benefit from their structural variability, polysaccharides have great potential in regulating cellular signals. Some polysaccharides exert direct anti-tumor effects by inducing cell cycle arrest and apoptosis, while the majority of polysaccharides can regulate the host immune system and indirectly inhibit tumors by activating either non-specific or specific immune responses. As the essential of microenvironment in the process of tumor development has been gradually revealed, some polysaccharides were found to inhibit the proliferation and metastasis of tumor cells via tumoral niche modulation. Here, we focused on natural polysaccharides with biomedical application potential, reviewed the recent advancement in their immunomodulation function and highlighted the importance of their signaling transduction feature for the antitumor drug development.

Fusel oil reaction in pressurized water: characterization and antimicrobial activity

This work aimed to investigate the reaction of fusel oil (FO) with pressurized water in a continuous flow reactor, in order to verify the effect of operating conditions (temperature and alcohol to water ratio) on the formation of reaction products, as well as to potentiate the antimicrobial activity of FO. The characterization of the FO was performed by high resolution mass spectrometry (ESI-TOF) and by a chromatograph coupled to mass spectrometry (GC-MS), and the reaction products were characterized by ESI-TOF and evaluated for antifungal potential. From the results, it was verified that the FO contained 70.58 wt% of isoamyl alcohol and was formed mainly by the organic functions alcohols, aldehydes, ketones and lipids. The reaction mechanisms that prevailed during the reactions conducted in subcritical and supercritical states were dehydration and reduction, respectively, making it possible to identify pyrazine derivatives compounds in the reaction products. The fungus Irpex lacteus showed greater resistance under the application of reaction products, and the products obtained at 300 °C and 400 °C showed an inhibition percentage of 96.07% to Schizophyllum commune and 96.50% to Trametes versicolor, respectively.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-022-03429-3.

Chemical Characterization and Biological Functions of Hot Alkali-Soluble Crude Polysaccharide from the Water-Insoluble Residue of Macrocybe lobayensis (Agaricomycetes) Fruit Bodies

Macrocybe lobayensis owe popularity in several traditional cultures not only for delectable taste but also for its nutraceutical profile conveying great health benefits. Previous investigations have enumerated several bioactivities of the valuable mushroom such as antioxidant, anti-ageing, immune-modulation, and anti-tumor properties where polysaccharides played the key role. Macrofungi polymers are generally isolated by the conventional hot water process discarding the residue which still contains plenty of therapeutic components. The present study thus aimed to re-use such leftover of the edible macrofungus by immersing it in NaOH solution at high temperature supporting circular economy. Consequently a polysaccharide fraction, namely ML-HAP, was isolated that was found to be consisted of a homogenous heteropolysaccharide with molecular weight of ~ 128 kDa and β-glucan as the chief ingredient as evident by spectroscopy, gel-permeation chromatography, high performance thin-layer chromatography, and Fourier transform infrared. Antioxidant activity assays revealed that the macromolecules possess good radical scavenging, metal ion binding and reducing power. Nevertheless, strong immune-potentiation was also recorded as the extract triggered murine macrophage cell viability, pinocytosis, nitric oxide production and morpho-dynamics within 24 h where the best effect was executed at the level of 100 µg/mL. Altogether, the polysaccharides extracted from M. lobayensis exhibited a potent application prospect in functional food, pharmaceutical, nutraceutical and health care industries that could raise economic value of the underexplored mushroom.

Structural characterization and immunomodulatory activity of a mannan from Helvella leucopus

A new polysaccharide fraction HLP-1 (2.55 × 10⁵ Da) was obtained from the fruiting bodies of Helvella leucopus. Structural characterization of HLP-1 was elucidated by infrared spectroscopy, monosaccharide composition analysis, methylation analysis, nuclear magnetic resonance spectroscopy, scanning electron microscopy and Congo red assay. HLP-1 was a mannan with a backbone of →6)-α-D-Manp(1 → 4)- α-D-Manp(1 → 6)-α-D-Manp(1 → 3)-α-D-Manp(1 → 4)-α-D-Manp(1 → 3)-α-D-Manp(1→, which branched at the O-6 position and terminated with T-β-D-Manp. Moreover, HLP-1 could significantly improve the proliferation and neutral red phagocytosis of RAW264.7. Besides, HLP-1 could stimulate the production of nitric oxide (NO), ROS, tumor necrosis factor-α (TNF-α), interleukin-1 beta (IL-1β) and interleukin-6 (IL-6). HLP-1 induced macrophage activation via NF-κB signal pathway. These findings indicated that HLP-1 was a potential immune enhancement agent applied in functional foods.

The Effect of Flammulina velutipes Polysaccharide on Immunization Analyzed by Intestinal Flora and Proteomics

Proteomics and intestinal flora were used to determine the mechanism of immune modulatory effects of Flammulina velutipes polysaccharide on immunosuppressed mice. The results showed that compared with the model group, F. velutipes polysaccharide could increase thymus and spleen indices and improve thymus tissue structure in mice; IL-2 and IL-4 contents were significantly increased and IL-6 and TNF-α contents were significantly decreased; serum acid phosphatase (ACP), lactate dehydrogenase (LDH) and total antioxidant capacity (T-AOC) activities were increased (P < 0.05); in the liver, superoxide dismutase (SOD) and catalase (CAT) activities were increased (P < 0.001), while malondialdehyde (MDA) content was decreased (P < 0.001). Proteomics discovered that F. velutipes polysaccharides may exert immune modulatory effects by participating in signaling pathways such as immune diseases, transport and catabolism, phagosomes and influenza A, regulating the immune-related proteins Transferrin receptor protein 1 (TFRC) and Radical S-adenosyl methionine domain-containing protein 2 (RSAD2), etc. Gut microbial studies showed that F. velutipes polysaccharides could increase the abundance of intestinal flora and improve the flora structure. Compared to the model group, the content of short-chain fatty acids (SCFAs) and the relative abundance of SCFA-producers Bacteroides and Alloprevotella were increased in the F. velutipes polysaccharide administration group, while Lachnospiraceae_NK4A136_group and f_Lachnospiraceae_Unclassified decreased in relative abundance. Thus, F. velutipes polysaccharide may play an immunomodulatory role by regulating the intestinal environment and improving the balance of flora.

Effect of surfactants on the production of polysaccharides from Schizophyllum commune through submerged fermentation

Schizophyllum commune (S. commune) polysaccharides are biomacromolecules with multiple biological activities and wide applications. In this study, polysaccharide production through submerged fermentation of S. commune using different surfactants was investigated. The addition of 1 g/L of polyoxyethylene sorbitan monooleate (Tween 80) at the beginning of the fermentation showed the best promotional effects on collective exopolysaccharide (EPS) production (which increased by 37.17%) while shortening the production cycle by 2 days. The monosaccharide composition of the EPS produced when the added Tween 80 was similar to that of the control; however, the molecular weight (Mw) was lower. Notably, the addition of Tween 80 significantly increased the ATP levels and the transcription levels of phosphoglucomutase and β-glucan synthase genes in the polysaccharide synthesis pathway. The addition of Tween 80 reduced the pellet size of the mycelium compared to that of the control, but did not significantly change the microstructure of the mycelial cells. This study proposes an efficient strategy for the production of polysaccharides through submerged fermentation of S. commune, and elucidates the detailed mechanism of using Tween 80 as a fermentation stimulatory reagent.

Structural Elucidation and Immunostimulatory Activities of Quinoa Non-starch Polysaccharide Before and After Deproteinization

Non-starch polysaccharides derived from natural resources play a significant role in the field of food science and human health due to their extensive distribution in nature and less toxicity. In this order, the immunostimulatory activity of a non-starch polysaccharide (CQNP) from Chenopodium quinoa was examined before and after deproteination in murine macrophage RAW 264.7 cells. The chemical composition of CQNP and deproteinated-CQNP (D-CQNP) were spectrometrically analysed that revealed the presence of carbohydrate (22.7 ± 0.8% and 39.5 ± 0.8%), protein (41.4 ± 0.5% and 20.8 ± 0.5%) and uronic acid (8.7 ± 0.3% and 6.7 ± 0.2%). The monosaccharide composition results exposed that CQNP possesses a high amount of arabinose (34.5 ± 0.3) followed by galactose (26.5 ± 0.2), glucose (21.9 ± 0.3), rhamnose (7.0 ± 0.1), mannose (6.0 ± 0.1) and xylose (4.2 ± 0.2). However, after deproteination, a difference was found in the order of the monosaccharide components, with galactose (41.1 ± 0.5) as a major unit followed by arabinose (34.7 ± 0.5), rhamnose (10.9 ± 0.2), glucose (6.6 ± 0.2), mannose (3.4 ± 0.2) and xylose (3.2 ± 0.2). Further, D-CQNP potentially stimulate the RAW 264.7 cells through the production of nitric oxide (NO), upregulating inducible nitric oxide synthase (iNOS) and various pro-inflammatory cytokines including interleukin (IL)-1β, IL-6, IL-10, and tumor necrosis factor-alpha (TNF-α). Moreover, stimulation of RAW 264.7 cells by D-CQNP takes place along the NF-κB and the MAPKs signaling pathways through the expression of cluster of differentiation 40 (CD40). This results demonstrate that RAW 264.7 cells are effectively stimulated after removal of the protein content in C. quinoa non-starch polysaccharides, which could be useful for develop a new immunostimulant agent.

Interaction between polysaccharides and toll-like receptor 4: Primary structural role, immune balance perspective, and 3D interaction model hypothesis

Various structural types of polysaccharides are recognized by toll-like receptor 4 (TLR4). However, the mechanism of interaction between the polysaccharides with different structures and TLR4 is unclarified. This review summarized the primary structure of polysaccharides related to TLR4, mainly including molecular weight, monosaccharide composition, glycosidic bonds, functional groups, and branched-chain structure. The optimal primary structure for interacting with TLR4 was obtained by the statistical analysis. Besides, the dual-directional regulation of TLR4 signaling cascade by polysaccharides was also elucidated from an immune balance perspective. Finally, the 3D interaction model of polysaccharides to TLR4-myeloid differentiation factor 2 (MD2) complex was hypothesized according to the LPS-TLR4-MD2 dimerization model and the polysaccharides solution conformation. The essence of polysaccharides binding to TLR4-MD2 complex is a multivalent non-covalent bond interaction. All the arguments summarized in this review are intended to provide some new insights into the interaction between polysaccharides and TLR4.

Ferrum phosphoricum D12 Treatment Affects J774A.1 Cell Proliferation, Transcription Levels of Iron Metabolism, Antioxidant Defense, and Inflammation-related Genes

BACKGROUND

 Ferrum phosphoricum (FP) is prescribed as a homeopathic remedy to treat the early stages of fever and inflammation in cases of colds or flu, muscle fatigue and anemia. We aimed to analyze the molecular mechanisms of action of FP D12 on cell proliferation and mRNA expression of iron metabolism, antioxidant defense and inflammation-related genes in mouse J774A.1 macrophages.

METHODS

 Cell proliferation was examined using the MTT test. RT-qPCR analyses were performed to estimate gene expression changes. Relative gene expression levels were calculated using the 2^-ΔΔCt method. The effect of treatment using FP D12 tablets was compared with that using placebo tablets (PT).

RESULTS

 FP D12 in low concentrations (0.0125 mg/mL to 0.025 mg/mL) significantly stimulated proliferation of J774A.1 cells by up to 11% (p < 0.01) versus control untreated cells and by up to 40% (p < 0.01) versus PT-treated cells in the respective concentration. FP D12 versus PT induced a significant increase in mRNA expression of ferritin light chain (Ftl1) (by 8-fold, p < 0.01), β-2-microglobulin (B2m) (by 2.5-fold, p < 0.05) and iron-responsive element binding protein 2 (Ireb2) (by 4-fold, p < 0.05), and induced a slight decrease in myosin IE (Myo1e) mRNA expression levels (by 0.4-fold, p < 0.01) in macrophages. A highly significant (r² = 0.99, p < 0.05) correlation was observed between Ireb2 and B2m transcription levels. Significant stimulation of antioxidant enzyme Gpx-1 (by 1.27-fold, p < 0.01) in cells by 0.025 mg/mL FP D12, but a slight decrease (by 0.12-fold, p < 0.05) in 0.0125 mg/mL-treated cells, was observed. A significant increase in the gene expression of IL-1β (by 3.5-fold, р < 0.05) in macrophages was also detected.

CONCLUSION

 Ferrum phosphoricum in D12 dilution potentially exhibits iron retention, antioxidant and immunomodulation activities, possibly by modulating transcription levels of related genes in non-stimulated mouse macrophages.

Extraction, Structural Characterisation, and Immunomodulatory Properties of Edible Amanitahemibapha subspecies javanica (Corner and Bas) Mucilage Polysaccharide as a Potential of Functional Food

This research aimed to extract mucilage polysaccharides (MP) from Amanita hemibapha subspecies javanica (Corner and Bas), and further fractionate them using anion-exchange chromatography, yielding two fractions (MPF1 and MPF2). The crude extract, and fractions mainly consisted of carbohydrates (83.5-93.2%) with minor amounts of proteins (5.40-7.20%), and sulphates (1.40-9.30%). Determination of the monosaccharide composition revealed that glucose was the major unit, followed by galactose, mannose, rhamnose, and arabinose. The average molecular weight (MW) of the crude extract and fractions was in the range 104.0-479.4 × 103 g/mol. Interestingly, the crude extract, and fractions did not cause any toxic effect in RAW264.7 cells. However, they stimulated the RAW264.7 cells to release nitric oxide and cytokines through the activation of nuclear factor-kappa B (NF-κB), and mitogen-activated protein kinase (MAPK) pathways via cell surface TLR4. Structural analysis of the most immunestimulating extract fraction, MPF2, revealed that the main backbone consisted of α-D-(1→6)-glucopyranoside. These results suggest that the MPs derived from A. hemibapha subspecies javanica (Corner and Bas) are potent in enhancing immunity; hence, they can be used as a functional ingredient in food products.

Submerged cultivation, characterization and in vitro antitumor activity of polysaccharides from Schizophyllum radiatum

Production of polysaccharides by white-rot-fungi in submerged cultivation has several advantages due to process control. This work deals with the submerged cultivation, extraction and antitumor activity of polysaccharides from a wild strain of Schizophyllum radiatum isolated from a tropical forest of Colombia. The mushroom was cultivated in laboratory conditions, and classified by classical and molecular taxonomy. Submerged cultivation was performed in a bioreactor of 5 L using a ligninolytic residue as substrate. The fermentation conditions were 30 ± 1 °C, pH 4.5, 300 rpm and 1.5 vvm of air for 4 days. The yields were 16.8 g/L (w/v) of biomass, and after extraction, 0.6 g/L of water-soluble exopolysaccharide (SEPS) and 2.01 % (w/w) of water-soluble intrapolysaccharide (SIPS) were obtained. In each extract total carbohydrate, glucans and protein contents were determined. Also, nuclear magnetic resonance (NMR), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, X-ray diffractometry (XRD), high performance liquid chromatography with refraction index detection (HPLC-RI), high performance gel permeation chromatography (HPGPC) and Nuclear Magnetic Resonance (NMR) analysis were performed. Results indicated that SEPS and SIPS are heteropolysaccharides with amorphous structure and high molecular weights. Antitumor and immunostimulant activity was evaluated in different cancer cell lines. The results suggest these polysaccharides have direct and indirect antitumor activity activating immune cells such as macrophages. These findings enhance our knowledge about new sources of fungal metabolites that serve as adjuvant, cheaper and less harmful alternatives to cancer treatment.

The activation effects of fucoidan from sea cucumber Stichopus chloronotus on RAW264.7 cells via TLR2/4-NF-κB pathway and its structure-activity relationship

Sea cucumber Stichopus chloronotus is a traditional tonic food with high nutritive value in Southern China. Fucoidan from sea cucumber Stichopus chloronotus (Fuc-Sc) is its main bio-active polysaccharide, the immune-activation effects of which have been fully investigated on RAW264.7 cells in the present study. The results indicated that Fuc-Sc could stimulate the RAW264.7 cells by promoting the production of NO, TNF-α, IL-6 and IL-10. Western blot and RT-PCR analysis revealed that TLR4 and TLR2 were involved in the recognition of Fuc-Sc and activation of downstream NF-κB signal pathway. Moreover, the chemical structure parameter molecular weight showed obvious impact on the stimulation effects of Fuc-Sc on NO production. Degraded product of Fuc-Sc with weight average molecular weight of 113.1 × 10⁴ Da exhibited higher activities than that of intact Fuc-Sc, suggesting the existent of optimum chain length to exert its highest activities. Taken together, Fuc-Sc exerted its immunostimulating activity via TLR2/4 activation of NF-κB pathway and showed potentials to be a good immunoadjuvant.

Biologically active polysaccharide from edible mushrooms: A review

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

Sulfated galactan from Halymenia dilatata enhance the antioxidant properties and prevents Aeromonas hydrophila infection in tilapia fish: In vitro and in vivo study

The structural characterization and pharmaceutical perspective of sulfated galactan from Halymenia dilatata (Hd-SG) were reported in this study. The Hd-SG consists of carbohydrate (58.5 ± 0.9%), sulfate (28.7 ± 0.9%) and protein (2.7 ± 0.2%). The existence of carbon (28.14%), hydrogen (5.50%), nitrogen (0.51%) and sulfur (8.26%) was confirmed in CHNS analysis. The Hd-SG was mainly comprising of galactose and mannose connected by (1 → 4)-glycosidic linkages, and it shows the molecular weight of 900.9 × 103 g/mol in high-performance size exclusion chromatography (HPSEC). The Hd-SG exhibited the dose depended on antioxidant activities. The in vitro and in vivo studies proved the antibacterial efficacy of Hd-SG against Aeromonas hydrophila. The pre-treated Oreochromis fish with Hd-SG (2.0 g/0.1 kg of feed) showed the highest survival, antioxidant, and improved histological changes than the fish infected with A. hydrophila alone. These results concluded that the isolated Hd-SG has extensive therapeutic properties, and it can be used as preventive medicine.