Abelmoschi Corolla polysaccharides and related metabolite ameliorates colitis via modulating gut microbiota and regulating the FXR/STAT3 signaling pathway

Ulcerative Colitis (UC) is a chronic inflammatory disease of the intestinal tract with unknown definitive etiology. Polysaccharides are among the most important active components of Abelmoschi Corolla, exhibitings various pharmacological activities such as antioxidation and immunomodulation. However, no studies have yet reported the application of Abelmoschi Corolla Polysaccharides (ACP) in treating UC. This study aims to highlight the therapeutic efficacy of ACP in UC and reveal the underlying mechanism. The potential therapeutic effect is initially verified using a dextran sodium sulfate (DSS)-induced colitis model. 16S rRNA sequencing is performed using feces samples and untargeted metabolomics using serum samples to further reveal that ACP reprograms the dysbiosis triggered by UC progression, increases the abundance of Bacteroides spp., Blautia spp., and Parabacteroides spp. at the genus level and enriches the serum concentration of 7-ketodeoxycholic acid (7-KDA). Furthermore, using the FXR-/- mouse model, it is revealed that Farnesoid X Receptor (FXR) is a key target for ACP and the metabolite 7-KDA to block STAT3 phosphorylation by repairing the intestinal barrier to attenuate UC. Taken together, this work highlights the therapeutic potential of ACP against UC, mainly exerting its effects via modulating gut microbiota and regulating the FXR/STAT3 signaling pathway.

The biomolecules of Euglena gracilis: Harnessing biology for natural solutions to future problems

Over the past decade, the autotrophic and heterotrophic protist Euglena gracilis (E. gracilis) has gained popularity across the studies of environmental science, biosynthesis experiments, and nutritional substitutes. The unique physiology and versatile metabolism of E. gracilis have been a recent topic of interest to many researchers who continue to understand the complexity and possibilities of using E. gracilis biomolecule production. In this review, we present a comprehensive representation of recent literature outlining the various uses of biomolecules derived from E. gracilis across the fields of natural product biosynthesis, as a nutritional substitute, and as bioremediation tools. In addition, we highlight effective strategies for altering metabolite production using abiotic stressors and growth conditions. To better understand metabolite biosynthesis and its role in E. gracilis, integrated studies involving genomics, metabolomics, and proteomics should be considered. Together, we show how the ongoing advancements in E. gracilis related research continue to broaden applications in the biosynthetic sector and highlight future works that would strengthen our understanding of overall Euglena metabolism.

The effects of cereal β-glucans on cardiovascular risk factors and the role of the gut microbiome

The human gut microbiome has emerged as a key influencer of human health and disease, particularly through interactions with dietary fiber. However, national dietary guidelines worldwide are only beginning to capitalize on the potential of microbiome research, which has established the vital role of host-microbe interactions in mediating the physiological effects of diet on overall health and disease. β-glucans have been demonstrated to modulate the composition of the gut microbiota, leading to improved outcomes in cardiovascular disease (CVD). Raised serum cholesterol and blood pressure are important modifiable risk factors in the development of CVD and emerging evidence highlights the role of the gut microbiota in ameliorating such biomarkers and clinical characteristics of the disease. The proposed mechanism of action of β-glucans on the pathophysiological mechanisms of disease have yet to be elucidated. Validating gaps in the literature may substantiate β-glucans as a potential novel dietary therapy against modifiable risk factors for CVD and would further support the public health significance of including a habitual fiber-rich diet.

The anti-infective effect of β-glucans in children

Background: β-glucans are bioactive β-D-glucose polysaccharides of natural origin, presenting antimicrobial and immunomodulation properties, with a low risk of toxicity. Objectives: This scoping review aims to present the current knowledge on the anti-infective properties of β-glucans in the pediatric population. Methods: We used the PRISMA Extension for Scoping Reviews Checklist to prepare this review. Studies were identified by electronic searches of Pubmed, Embase, and Cochrane databases up to May 2021. Results: The primary search allowed us to find 6232 studies, twelve of which were finally included in the analysis. Eight studies were designed as randomized, placebo-controlled trials, while in four studies the intervention outcome was compared with the pre-intervention period in the same group. The type of preparation and doses varied between studies: in five trials pleuran was administered (in dose 10 mg/5 kg of body weight/day), and in one study baker's yeast β-glucan was used (in two doses: 35 mg/day and 75 mg/day). In six other studies, the analyzed preparation comprised β-glucan and other substances. The shortest study lasted seven days, while the most prolonged intervention lasted six months, followed by six months of follow-up. Ten out of twelve trials demonstrated the effectiveness of β-glucans in reducing respiratory tract infection incidence or alleviation of upper respiratory tract infection symptoms. Ten out of twelve studies have reported a good tolerance and safety profile. Conclusions: Good tolerance of β-glucans shows a favorable benefit-risk ratio of this type of intervention. Nevertheless, further monitoring of their efficacy and safety in high-quality research is necessary.

Effect of modification methods on the physical properties and immunomodulatory activity of particulate β-glucan

β-Glucan is an immunoenhancing agent whose biological activities are linked to molecular structure. On that basis, the polysaccharide can be physiochemically modified to produce valuable functional materials. This study investigated the physical properties and immunostimulatory activity of modified β-glucan. Alkali-treated β-glucan had a distinct shape and smaller particle size than untreated β-glucan. The reduced particle size was conducive to the stability of the suspension because the β-glucan appeared to be completely dissolved by this treatment, forming an amorphous mass. Furthermore, alkali treatment improved the immunostimulating activity of β-glucan, whereas exposure of macrophages to heat-treated β-glucan decreased their immune activity. β-Glucan with reduced particle size by wet-grinding also displayed immunomodulatory activities. These results suggested that the particle size of β-glucan is a key factor in β-glucan-induced immune responses of macrophages. Thus, the modification of the β-glucan particle size provides new opportunities for developing immunoenhancing nutraceuticals or pharmacological therapies in the future.

β-glucans from Euglena gracilis or Saccharomyces cerevisiae effects on immunity and inflammatory parameters in dogs

Considering the differences in molecular structure and function, the effects of β-1,3-glucans from Euglena gracilis and β-1,3/1,6-glucans from Saccharomyces cerevisiae on immune and inflammatory activities in dogs were compared. Four diets were compared: control without β-glucans (CON), 0.15 mg/kg BW/day of β-1,3/1,6-glucans (Β-Y15), 0.15 mg/kg BW/day of β-1,3-glucans (Β-S15), and 0.30 mg/kg BW/day of β-1,3-glucans (Β-S30). Thirty-two healthy dogs (eight per diet) were organized in a block design. All animals were fed CON for a 42-day washout period and then sorted into one of four diets for 42 days. Blood and faeces were collected at the beginning and end of the food intake period and analysed for serum and faecal cytokines, ex vivo production of hydrogen peroxide (H2O2) and nitric oxide (NO), phagocytic activity of neutrophils and monocytes, C-reactive protein (CRP), ex vivo production of IgG, and faecal concentrations of IgA and calprotectin. Data were evaluated using analysis of covariance and compared using Tukey's test (P<0.05). Dogs fed Β-Y15 showed higher serum IL-2 than dogs fed Β-S30 (P<0.05). A higher phagocytic index of monocytes was observed in dogs fed the B-S15 diet than in those fed the other diets, and a higher neutrophil phagocytic index was observed for B-S15 and B-Y15 than in dogs fed the CON diet (P<0.05). Monocytes from dogs fed B-S15 and B-S30 produced more NO and less H2O2 than those from the CON and B-Y15 groups (P<0.05). Despite in the reference value, CRP levels were higher in dogs fed B-S15 and B-S30 diets (P<0.05). β-1,3/1,6-glucan showed cell-mediated activation of the immune system, with increased serum IL-2 and neutrophil phagocytic index, whereas β-1,3-glucan acted on the immune system by increasing the ex vivo production of NO by monocytes, neutrophil phagocytic index, and serum CRP. Calprotectin and CRP levels did not support inflammation or other health issues related to β-glucan intake. In conclusion, both β-glucan sources modulated some immune and inflammatory parameters in dogs, however, different pathways have been suggested for the recognition and action of these molecules, reinforcing the necessity for further mechanistic studies, especially for E. gracilis β-1,3-glucan.

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.

Enhancing farmed striped catfish (Pangasianodon hypophthalmus) robustness through dietary β-glucan

β-glucan is a well-documented feed additive for its potent immunostimulatory properties in many farmed fish species. This study examined how it can also be a promising growth promoter, modulate antioxidant enzyme activities, and act as an anti-stress agent in striped catfish (Pangasianodon hypophthalmus). A 12-week feeding experiment was untaken to determine the effects of dietary β-glucan supplementation at graded levels (0, 0.5, 1.0, and 1.5 g kg-1). Measured indicators suggest that a dietary inclusion level of 1.5 g kg-1 β-glucan gave the highest positive responses: weight gain (120.10 g fish-1), survival (98.30%), and lower FCR (1.70) (P<0.05). Whole body proximate analysis had only revealed that crude protein was significantly affected by the dietary inclusion of β-glucan (P<0.05), with the highest protein content (19.70%) being in fish that were fed with 1.5 g kg-1 β-glucan. Although other inclusion levels (i.e., 0.5 and 1 g kg-1) of β-glucan did not enhance body protein content (P>0.05). The assessment of fatty acid composition in muscle, liver, and adipose tissues showed modifications with the inclusion of β-glucan. Antioxidative-related enzyme activities (inc. catalase, glutathione peroxidase, and superoxide dismutase) that were measured in the liver had higher levels when fed with β-glucan inclusion diets (P<0.05). Following the feed trial, fish were subjected to crowding stress treatment. It was subsequently found that catfish fed with β-glucan-based diet groups had lower levels of blood stress-related indicators compared to the control group with no dietary β-glucan. The use of 1.5 g kg-1 of dietary β-glucan resulted in the lowest measured levels of cortisol (43.13 ng mL-1) and glucose (50.16 mg dL-1). This study has demonstrated that the dietary inclusion of β-glucan can have functional benefits beyond the immunological enhancements in striped catfish. Furthermore, its use can increase production levels and mitigate the stress associated with intensive farming practices.

Polysaccharides (pectin, mucilage, and fructan inulin) and their fermented products: A critical analysis of their biochemical, gut interactions, and biological functions as antidiabetic agents

Diabetes mellitus is a globally metabolic endocrine syndrome marked by a deficiency of insulin secretion (type-1 DM) or glucose intolerance arising from insulin response impairment (type-2 DM) leading to abnormal glucose metabolism. With an increasing interest in natural dietary components for diabetes management, the identification of novel agents witnessed major discoveries. Plant-derived mucilage, pectin, and inulin are important non-starch polysaccharides that exhibit effective antidiabetic properties often termed soluble dietary fiber (SDF). SDF affects sugar metabolism through multiple mechanisms affecting glucose absorption and diffusion, modulation of carbohydrate metabolizing enzymes (α-amylase and α-glucosidase), ameliorating β-pancreatic cell dysfunction, and improving insulin release or sensitivity. Certain SDFs inhibit dipeptidyl peptidase-4 and influence the expression levels of genes related to glucose metabolism. This review is designed to discuss holistically and critically the antidiabetic effects of major SDF and their underlying mechanisms of action. This review should aid drug discovery approaches in developing novel natural antidiabetic drugs from SDF.

Potential promising anticancer applications of β-glucans: a review

β-Glucans are valuable functional polysaccharides distributed in nature, especially in the cell walls of fungi, yeasts, bacteria, and cereals. The unique features of β-glucans, such as water solubility, viscosity, molecular weight, and so on, have rendered them to be broadly applied in various food systems as well as in medicine to improve human health. Moreover, inhibition of cancer development could be achieved by an increase in immune system activity via β-glucans. β-glucans, which are part of a class of naturally occurring substances known as biological response modifiers (BRMs), have also shown evidence of being anti-tumorogenic, anti-cytotoxic, and anti-mutagenic. These properties make them attractive candidates for use as pharmaceutical health promoters. Along these lines, they could activate particular proteins or receptors, like lactosylceramide (LacCer), Dickin-1, complement receptor 3 (CR3), scavenge receptors (SR), and the toll-like receptor (TLR). This would cause the release of cytokines, which would then activate other antitumor immune cells, like macrophages stimulating neutrophils and monocytes. These cells are biased toward pro-inflammatory cytokine synthesis and phagocytosis enhancing the elicited immunological responses. So, to consider the importance of β-glucans, the present review introduces the structure characteristics, biological activity, and antitumor functions of fungal β-glucans, as well as their application.

Stimulus-Responsive Hydrogels as Drug Delivery Systems for Inflammation Targeted Therapy

Deregulated inflammations induced by various factors are one of the most common diseases in people's daily life, while severe inflammation can even lead to death. Thus, the efficient treatment of inflammation has always been the hot topic in the research of medicine. In the past decades, as a potential biomaterial, stimuli-responsive hydrogels have been a focus of attention for the inflammation treatment due to their excellent biocompatibility and design flexibility. Recently, thanks to the rapid development of nanotechnology and material science, more and more efforts have been made to develop safer, more personal and more effective hydrogels for the therapy of some frequent but tough inflammations such as sepsis, rheumatoid arthritis, osteoarthritis, periodontitis, and ulcerative colitis. Herein, from recent studies and articles, the conventional and emerging hydrogels in the delivery of anti-inflammatory drugs and the therapy for various inflammations are summarized. And their prospects of clinical translation and future development are also discussed in further detail.

Exploring β-glucan as a micro-nano system for oral delivery targeted the colon

The critical role of oral colon-specific delivery systems (OCDDS) is important for delivering active agents to the colon and rectum specifically via the oral route. The use of micro/nanostructured OCDDS further improves drug stability, bioavailability, and retention time, leading to enhanced therapeutic effects. However, designing micro/nanoscale OCDDSs is challenging due to pH changes, enzymatic degradation, and systemic absorption and metabolism. Biodegradable natural polysaccharides are a promising solution to these problems, and β-glucan is one of the most promising natural polysaccharides due to its unique structural features, conformational flexibility, and specific processing properties. This review covers the diverse chemical structures of β-glucan, its benefits (biocompatibility, easy modification, and colon-specific degradation), and various β-glucan-based micro/nanosized OCDDSs, as well as their drawbacks. The potential of β-glucan offers exciting new opportunities for colon-specific drug delivery.

Activation of Immune and Antiviral Effects by Euglena Extracts: A Review

Influenza is an acute respiratory illness caused by influenza virus infection, which is managed using vaccines and antiviral drugs. Recently, the antiviral effects of plants and foods have gained attention. Euglena is a motile unicellular alga and eukaryotic photosynthetic microorganism. It has secondary chloroplasts and is a mixotroph able to feed by photosynthesis or phagocytosis. This review summarizes the influenza treatment effects of Euglena from the perspective of a functional food that is attracting attention. While it has been reported that Euglena contributes to suppressing blood sugar levels and ameliorates symptoms caused by stress by acting on the autonomic nervous system, the immunostimulatory and antiviral activities of Euglena have also been reported. In this review, I focused on the immunostimulation of antiviral activity via the intestinal environment and the suppression of viral replication in infected cells. The functions of specific components of Euglena, which also serves as the source of a wide range of nutrients such as vitamins, minerals, amino acids, unsaturated fatty acids, and β-1,3-glucan (paramylon), are also reviewed. Euglena has animal and plant properties and natural compounds with a wide range of functions, providing crucial information for improved antiviral strategies.

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.

Safety of paramylon as a novel food pursuant to Regulation (EU) 2015/2283

Following a request from the European Commission, the EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA) was asked to deliver an opinion on paramylon as a novel food (NF) pursuant to Regulation (EU) 2015/2283. Paramylon is a linear, unbranched beta-1,3-ᴅ-glucan polymer that is isolated from the single-cell microalga Euglena gracilis. The NF consists of at least 95% beta-glucan and minor amounts of protein, fat, ash and moisture. The applicant proposed to use the NF in food supplements, as a food ingredient added to a number of food categories and in foods for total diet replacement for weight control. In 2019, E. gracilis was attributed the qualified presumption of safety (QPS) status with the qualification 'for production purposes only', which includes food products based on microbial biomass of the microalga. Based on the information provided, E. gracilis is not expected to survive the manufacturing process. The submitted toxicity studies did not raise safety concerns. No adverse effects were observed in the subchronic toxicity studies, up to the highest dose tested, i.e. 5,000 mg NF/kg body weight per day. In view of the QPS status of the source of the NF, supported by the manufacturing process, compositional data and lack of toxicity observed in the toxicity studies, the Panel has no safety concerns and concludes that the NF, i.e. paramylon, is safe under the proposed uses and use levels.

Optimizing the synthesis of yeast Beta-glucan via response surface methodology for nanotechnology application

BACKGROUND

The production of biopolymers from waste resources is a growing trend, especially in high-population countries like Egypt. Beta-glucan (β-glucan) belongs to natural polysaccharides that are derived from plant and microbial origins. In this study, following increasing demands for β-glucan owing to its bioactive properties, a statistical model to enhance microbial β-glucan production was evaluated for its usefulness to the food and pharmaceutical industries. In addition, a trial to convert β-glucan polymer to nanostructure form was done to increase its bioactivity.

RESULTS

Ingredients of low-cost media based on agro-industrial wastes were described using Plackett-Burman and central composite design of response surface methodology for optimizing yeast β-glucan. Minerals and vitamin concentrations significantly influenced β-glucan yield for Kluyveromyces lactis and nitrogen and phosphate sources for Meyerozyma guilliermondii. The maximum predicted yields of β-glucan recovered from K. lactis and M. guilliermondii after optimizing the medium ingredients were 407 and 1188 mg/100 ml; respectively. For the first time, yeast β-glucan nanoparticles (βGN) were synthesized from the β-glucan polymer using N-dimethylformamide as a stabilizer and characterized using UV-vis spectroscopy, transmission electron microscope (TEM), dynamic light scattering (DLS) and Fourier transform infrared spectroscopy (FT-IR). The average size of βGN was about 300 nm as determined by DLS. The quantitative variation of functional groups between β-glucan polymer and βGN was evaluated by FT-IR for explaining the difference in their biological activity against Normal Homo sapiens-Hela contaminant and Hepatic cancer cell lines.

CONCLUSIONS

Enriching the low-cost media based on agro-industrial wastes with nutritional ingredients improves the yield of yeast β-glucan. The present study succeeds to form β-glucan nanoparticles by a simple method.

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.

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.

Interaction between β-glucans and gut microbiota: a comprehensive review

Gut microbiota (GMB) in humans plays a crucial role in health and diseases. Diet can regulate the composition and function of GMB which are associated with different human diseases. Dietary fibers can induce different health benefits through stimulation of beneficial GMB. β-glucans (BGs) as dietary fibers have gained much interest due to their various functional properties. They can have therapeutic roles on gut health based on modulation of GMB, intestinal fermentation, production of different metabolites, and so on. There is an increasing interest in food industries in commercial application of BG as a bioactive substance into food formulations. The aim of this review is considering the metabolizing of BGs by GMB, effects of BGs on the variation of GMB population, influence of BGs on the gut infections, prebiotic effects of BGs in the gut, in vivo and in vitro fermentation of BGs and effects of processing on BG fermentability.

Glucans, Paramylon and Other Algae Bioactive Molecules

Algae (macro- and micro-algae) can be defined as light-driven cell factories that synthesize bioactive compounds consisting of primary metabolites (i [...].

Synthesis and evaluation of 1,5-dithialaminaribiose and -triose tetravalent constructs

We report the synthesis of novel tetravalent glucoclusters containing 1,5-dithia mimetics of laminaribiose and triose. The new constructs were evaluated for their ability to inhibit anti-CR3 fluorescent staining of human neutrophils, for which they showed moderate affinity. Evaluation of the synthesized glycoclusters for their ability to inhibit anti-Dectin-1 fluorescent staining of mouse macrophages revealed little to no affinity for Dectin-1.

Effects of fungal based bioactive compounds on human health: Review paper

Since the first years of history, microbial fermentation products such as bread, wine, yogurt and vinegar have always been noteworthy regarding their nutritional and health effects. Similarly, mushrooms have been a valuable food product in point of both nutrition and medicine due to their rich chemical components. Alternatively, filamentous fungi, which can be easier to produce, play an active role in the synthesis of some bioactive compounds, which are also important for health, as well as being rich in protein content. Therefore, this review presents some important bioactive compounds (bioactive peptides, chitin/chitosan, β-glucan, gamma-aminobutyric acid, L-carnitine, ergosterol and fructooligosaccharides) synthesized by fungal strains and their health benefits. In addition, potential probiotic- and prebiotic fungi were researched to determine their effects on gut microbiota. The current uses of fungal based bioactive compounds for cancer treatment were also discussed. The use of fungal strains in the food industry, especially to develop innovative food production, has been seen as promising microorganisms in obtaining healthy and nutritious food.

Effect of Supplementation with Saccharomyces cerevisiae and β-glucans to Mares During Late Gestation on Colostrum Quality and Passive Transfer of Immunity in Foals

The objective of this study was to determine whether supplementation with Saccharomyces cerevisiae or β-glucan, in the maternal diet during late pregnancy affects the concentration of total IgG in the colostrum of mares and influences the concentration of IgG in its foals. A total of 21 pregnant mares were used, aged 6±2 years, 3±1 pregnancies, 450±50kg in weight, and they were distributed into three groups: the control group (n=7); the S. cerevisiae group (n=7), which received 10¹⁰CFU of S. cerevisiae orally; and the β-glucan group (n=7), which received 0.35g of β-glucan orally. All groups started from the 300th day of their pregnancies until delivery. Samples of colostrum and serum from the mares were collected immediately after delivery. Blood samples from their foals were collected 12h after birth. The IgG measurement was performed using radial immunodiffusion. The results underwent a variance analysis. Higher concentrations of IgG were observed in the colostrum of mares that were supplemented with β-glucans (74.14±15.25 g/L) when compared to the control group (53.80g±10.95g/L). Serum IgG concentrations of foals born to mares supplemented with Saccharomyces cerevisiae (11.57±5.05 g/L) showed a significant difference, with a higher concentration of IgG in the serum compared to the control group. Therefore, this study provides evidence that manipulation of the mares' diets in late gestation to add β-glucan increased the IgG concentration in their colostrum. The addition of S. cerevisiae appears to improve the concentration of IgG in their foals within 12h after birth.

Transglycosylation of Stevioside by a Commercial β-Glucanase with Fungal Extracted β-Glucans as Donors

Abstract

Alternative sweeteners, such as steviol glucosides from the plant Stevia rebaudiana Bertoni, are becoming increasingly popular for the design of next-generation foodstuffs. However, the bitter aftertaste of native steviol glucosides is one of the main reasons behind consumer reluctance towards stevia-containing products. Biocatalysis could be a sustainable solution to this problem, through addition of glucosyl moieties to the molecule. Glycoside hydrolases are enzymes performing transglycosylation reactions, and they can be exploited for such modifications. In the present work, the commercial β-glucanase Finizym 250L® was employed for the transglycosylation of stevioside. After optimization of several reaction parameters, the maximal reaction yield obtained was 19%, with barley β-glucan as the glycosyl donor. With the aim to develop a sustainable process, β-glucan extracts from different fungal sources were prepared. Pulsed Electric Field pretreatment of mycelial biomass resulted in extracts with higher β-glucan content. The extracts were tested as alternative glucosyl donors, reaching up to 15.5% conversion yield, from Pleurotus-extracted β-glucan. Overall, in the present work a novel enzymatic process for the modification of stevioside is proposed, with concomitant valorization of β-glucans extracted from fungal biomass, potentially generated as a byproduct from other applications, in concert with the principles of circular economy.

Graphical Abstract

Potential Role of ROS in Butyrate- and Dietary Fiber-Mediated Growth Inhibition and Modulation of Cell Cycle-, Apoptosis- and Antioxidant-Relevant Proteins in LT97 Colon Adenoma and HT29 Colon Carcinoma Cells

The aim of the present study was to examine whether reactive oxygen species (ROS) contribute to chemopreventive effects of fermentation supernatants (FS) of different dietary fibers (Synergy1^®, oat-, barley-, yeast β-glucan, Curdlan) and butyrate as a fermentation metabolite. LT97 and HT29 cells were treated with butyrate and FS alone or with N-acetyl-cysteine (NAC) and their impact on ROS formation, cell growth, and protein expression (Cyclin D2, p21, PARP, Bid, GPx2) was investigated. Butyrate and FS significantly decreased cell growth. ROS levels were significantly increased, particularly in LT97 cells, while co-treatment with NAC decreased ROS formation and growth inhibitory effects in both cell lines. After treatment with butyrate and FS, Cyclin D2 expression was reduced in LT97 cells and p21 expression was increased in both cell lines. Levels of full-length PARP and Bid were decreased, while levels of cleaved PARP were enhanced. GPx2 expression was significantly reduced by fiber FS in HT29 cells. A notable effect of NAC on butyrate- and FS-modulated protein expression was observed exclusively for PARP and Bid in HT29 cells. From the present results, a contribution of ROS to growth inhibitory and apoptotic effects of butyrate and FS on LT97 and HT29 cells cannot be excluded.

Modulation of gut microbiota, blood metabolites, and disease resistance by dietary β-glucan in rainbow trout (Oncorhynchus mykiss)

BACKGROUND

Prebiotics are known to have a positive impact on fish health and growth rate, and β-glucans are among the most used prebiotics on the market. In this study, rainbow trout (Oncorhynchus mykiss) were treated with a β-1,3;1,6-glucan dietary supplement (at a dose of 0 g, 1 g, 10 g, and 50 g β-glucan per kg of feed). After 6 weeks, the effect of the β-glucan was evaluated by determining the changes in the microbiota and the blood serum metabolites in the fish. The impact of β-glucan on the immune system was evaluated through a challenge experiment with the bacterial fish pathogen Yersinia ruckeri.

RESULTS

The microbiota showed a significant change in terms of composition following β-glucan treatment, notably an increase in the relative abundance of members of the genus Aurantimicrobium, associated with a decreased abundance of the genera Carnobacterium and Deefgea. Furthermore, analysis of more than 200 metabolites revealed that the relative levels of 53 metabolites, in particular compounds related to phosphatidylcholines, were up- or downregulated in response to the dietary supplementation, this included the amino acid alanine that was significantly upregulated in the fish that had received the highest dose of β-glucan. Meanwhile, no strong effect could be detected on the resistance of the fish to the bacterial infection.

CONCLUSIONS

The present study illustrates the ability of β-glucans to modify the gut microbiota of fish, resulting in alteration of the metabolome and affecting fish health through the lipidome of rainbow trout.

Antioxidant, Immunomodulatory and Potential Anticancer Capacity of Polysaccharides (Glucans) from Euglena gracilis G.A. Klebs

The present study was carried out to determine the bioactivity of polysaccharides extracted from Euglena gracilis (EgPs). These were characterized by FT-IR and GC-MS. Cytotoxicity analyses (MTT) were performed on healthy human gingival fibroblast cell lines (HGF-1), obtaining an IC₅₀ of 228.66 µg mL^-1, and cell lines with anticancer activity for colon cancer (HCT-116), breast cancer (MCF-7), human leukemia (U-937, HL-60) and lung cancer (NCl-H460), showing that EgPs have anticancer activity, mainly in HTC-116 cells (IC₅₀ = 26.1 µg mL^-1). The immunological assay determined the immunomodulatory capacity of polysaccharides for the production of proinflammatory cytokines IL-6 and TNF-α in murine macrophages (RAW 264.7) and TNF-α in human monocytes (THP-1). It was observed that the EgPs had a stimulating capacity in the synthesis of these interleukins. The antioxidant capacity of polysaccharides and their biomass were analyzed using the ABTS method (18.30 ± 0.14% and (5.40 ± 0.56%, respectively, and the DPPH method for biomass (17.79 ± 0.57%). We quantitatively profiled HGF-1 proteins by liquid chromatography-tandem mass spectrometry analysis, coupled with 2-plex tandem mass tag labelling, in normal cells. In total, 1346 proteins were identified and quantified with high confidence, of which five were considered to be overexpressed. The data is available through ProteomeXchange, under identifier PXD029076.

Research progress on natural β-glucan in intestinal diseases

β-Glucan, an essential natural polysaccharide widely distributed in cereals and microorganisms, exhibits extensive biological activities, including immunoregulation, anti-inflammatory, antioxidant, antitumor properties, and flora regulation. Recently, increasing evidence has shown that β-glucan has activities that may be useful for treating intestinal diseases, such as inflammatory bowel disease (IBD), and colorectal cancer. The advantages of β-glucan, which include its multiple roles, safety, abundant sources, good encapsulation capacity, economic development costs, and clinical evidence, indicate that β-glucan is a promising polysaccharide that could be developed as a health product or medicine for the treatment of intestinal disease. Unfortunately, few reports have summarized the progress of studies investigating natural β-glucan in intestinal diseases. This review comprehensively summarizes the structure-activity relationship of β-glucan, its pharmacological mechanism in IBD and colorectal cancer, its absorption and transportation mechanisms, and its application in food, medicine, and drug delivery, which will be beneficial to further understand the role of β-glucan in intestinal diseases.

β-Glucan "Trained Immunity" Immunomodulatory Properties Potentiate Tissue Wound Management and Accelerate Fitness Recover

Introduction

It is well established that moderate physical activity can improve the immune status, rather excess or high-intensity physical exercise can cause damage to the immune system. In addition, muscle injuries resulting from increased frequency and intensity of exercises compromise innate immune activity and may decrease tissue regeneration. Thus, β-glucans, a natural compound, may represent an important substance with strong immunomodulatory properties acting as an immunostimulant therapy known as "trained immunity". This immune stimulating therapeutic is an immunological memory phenomenon linked to the innate immune system, triggering cellular changes at epigenetic, transcriptional, and functional levels, to regulate the immune system and recover its homeostasis with clinical benefits.

Conclusion

This narrative review works with the current evidence regarding β-glucans as a possible alternative therapy for wound healing and its safety and efficacy in the treatment of muscle injuries and physical recovery including other chronic conditions and diseases.

Are all fibres created equal with respect to lipid lowering? Comparing the effect of viscous dietary fibre to non-viscous fibre from cereal sources: a systematic review and meta-analysis of randomised controlled trials

Although compelling evidence from observational studies supports a positive association between consumption of cereal fibre and CVD risk reduction, randomised controlled trials (RCT) often target viscous fibre type as the prospective contributor to lipid lowering to reduce CVD risk. The objective of our study is to compare the lipids-lowering effects of viscous dietary fibre to non-viscous, cereal-type fibre in clinical studies. RCT that evaluated the effect of viscous dietary fibre compared with non-viscous, cereal fibre on LDL cholesterol and alternative lipid markers, with a duration of ≥ 3 weeks, in adults with or without hypercholesterolaemia were included. Medline, EMBASE, CINAHL and the Cochrane Central Register were searched through October 19, 2021. Data were extracted and assessed by two independent reviewers. The generic inverse variance method with random effects model was utilised to pool the data which were expressed as mean differences (MD) with 95 % CI. Eighty-nine trials met eligibility criteria (n 4755). MD for the effect of viscous dietary fibre compared with non-viscous cereal fibre were LDL cholesterol (MD = -0·26 mmol/l; 95 % CI: -0·30, -0·22 mmol/l; P < 0·01), non-HDL cholesterol (MD = -0·33 mmol/l; 95 % CI: -0·39, -0·28 mmol/l; P < 0·01) and Apo-B (MD = -0·04 g/l; 95 % CI: -0·06, -0·03 g/l; P < 0·01). Viscous dietary fibre reduces LDL cholesterol and alternative lipid markers relative to the fibre from cereal sources, hence may be a preferred type of fibre-based dietary intervention targeting CVD risk reduction.

Paramylon and Other Bioactive Molecules in Micro and Macroalgae

Many algae synthesize compounds that have exceptional properties of nutraceutical, pharmacological, and biomedical interest. Pigments, fatty acids, phenols, and polysaccharides are among the main compounds investigated so far. Polysaccharides are the most exploited compounds, widely used in pharmaceutical, food, and chemical industries, which are at present entering into more advanced applications by gaining importance, from a therapeutic point of view, as antioxidant, antimicrobial, antitumor, and immunomodulatory agents. Establishing algae as an alternative supplement would complement the sustainable and environmental requirements in the framework of human health and well-being. This review focuses on the proprieties and uses of the main micro- and macroalgae metabolites, describing their potential for application in the different industrial sectors, from food/feed to chemical and pharmacological. Further, current technologies involved in bioactive molecule extraction strategies are documented.

A review of paramylon processing routes from microalga biomass to non-derivatized and chemically modified products

Paramylon is a linear β-1,3-glucan, similar to curdlan, produced as intracellular granules by the microalga Euglena gracilis, a highly versatile and robust strain, able to grow under various trophic conditions, with valorization of CO_2, wastewaters, or food byproducts as nutrients. This review focuses in particular on the various processing routes leading to new potential paramylon based products. Due to its crystalline structure, involving triple helices stabilized by internal intermolecular hydrogen bonds, paramylon is neither water-soluble nor thermoplastic. The few solvents able to disrupt the triple helices, and to fully solubilize the polymer as random coils, allow non derivatizing shaping into films, fibers, and even nanofibers by a specific self-assembly mechanism. Chemical modification in homogeneous or heterogeneous conditions is also possible. The non-selective or regioselective substitution of the hydroxyl groups of glucosidic units leads to water-soluble ionic derivatives and thermoplastic paramylon esters with foreseen applications ranging from health to bioplastics.

Oral administration of Euglena gracilis paramylon ameliorates chemotherapy-induced leukocytopenia and gut dysbiosis in mice

Euglena gracilis (EUG) is a food supplement rich in beta-glucans, which are stored in the form of granules called paramylon. We determined whether EUG improved chemotherapy-induced leukocytopenia and dysbiosis. Mice were orally administered EUG prior to gemcitabine treatment. Analyses of the blood cell count, leukocyte population in the spleen, granulocyte/macrophage-colony-stimulating factor (GM-CSF) production by splenocytes, and fecal microbiome were conducted. The recovery of total leukocytes, neutrophils, and monocytes was accelerated after a single gemcitabine treatment. A more rapid lymphocyte recovery rate was observed after four gemcitabine treatments. No difference was observed in the percentage of T, B, or myeloid cells or in the expression of Dectin-1 in the spleens of the gemcitabine and EUG/gemcitabine groups. The EUG/gemcitabine group showed an enhanced GM-CSF production by lipopolysaccharides-stimulated splenocytes. Next-generation sequencing revealed that gemcitabine-induced dysbiosis was alleviated. This study demonstrated that EUG-derived beta-glucans could act as a biological response modifier as well as prebiotics for ameliorating chemotherapy-induced adverse effects.

Polysaccharide Peptide Extract From Coriolus versicolor Increased Tmax of Tamoxifen and Maintained Biochemical Serum Parameters, With No Change in the Metabolism of Tamoxifen in the Rat

Background: Polysaccharide peptide (PSP) extract of Coriolus versicolor (L.) Quél. (1886) (Trametes; Polyporaceae) is increasingly used in cancer to support the immune system. However, its interaction with tamoxifen is unknown.

Aim of the study: To investigate the effect of a PSP extract on the pharmacokinetics, biochemical parameters, and depletion of tamoxifen.

Methods: The pharmacokinetic and biochemical parameters of tamoxifen (20 mg/mL oral single dose and repeated dosing for 12 days) was investigated in female Sprague Dawley rats with or without PSP (340 mg/kg orally for 7 days) (n = 5 per group). Tamoxifen (5 µM) depletion rate with PSP (10–100 μg/mL) was measured in female rat hepatic microsomes in vitro.

Results: Compared to tamoxifen alone, the time to reach maximum concentration (T_max) significantly increased by 228% (4.15 ± 1.15 versus 13.6 ± 2.71 h) in the single tamoxifen dose with PSP and 93% (6 ± 2.17 versus 11.6 ± 0.4 h) in the repeated tamoxifen dosing with PSP (p < 0.05). No significant changes in the area-under-curve and maximum concentration were observed in the single dose and repeated tamoxifen dosing plus PSP compared to tamoxifen alone. Pharmacodynamically, the repeated tamoxifen dosing with PSP maintained 19 out of 23 hepatic, renal and cardiac biochemical serum parameters in rats compared to untreated rats (p > 0.05). PSP extract did not significantly alter in vitro intrinsic clearance of tamoxifen compared to tamoxifen control.

Conclusion: With the increased use of PSP as an adjunct therapy, this study highlights the importance of clinician’s knowledge of its interaction with tamoxifen to avoid compromising clinical actions and enhancing clinical therapy.

Bile Acid Sequestrants for Hypercholesterolemia Treatment Using Sustainable Biopolymers: Recent Advances and Future Perspectives

Bile acids, the endogenous steroid nucleus containing signaling molecules, are responsible for the regulation of multiple metabolic processes, including lipoprotein and glucose metabolism to maintain homeostasis. Within our body, they are directly produced from their immediate precursors, cholesterol C (low-density lipoprotein C, LDL-C), through the enzymatic catabolic process mediated by 7-α-hydroxylase (CYP7A1). Bile acid sequestrants (BASs) or amphiphilic resins that are nonabsorbable to the human body (being complex high molecular weight polymers/electrolytes) are one of the classes of drugs used to treat hypercholesterolemia (a high plasma cholesterol level) or dyslipidemia (lipid abnormalities in the body); thus, they have been used clinically for more than 50 years with strong safety profiles as demonstrated by the Lipid Research Council-Cardiovascular Primary Prevention Trial (LRC-CPPT). They reduce plasma LDL-C and can slightly increase high-density lipoprotein C (HDL-C) levels, whereas many of the recent clinical studies have demonstrated that they can reduce glucose levels in patients with type 2 diabetes mellitus (T2DM). However, due to higher daily dosage requirements, lower efficacy in LDL-C reduction, and concomitant drug malabsorption, research to develop an "ideal" BAS from sustainable or natural sources with better LDL-C lowering efficacy and glucose regulations and lower side effects is being pursued. This Review discusses some recent developments and their corresponding efficacies as bile removal or LDL-C reduction of natural biopolymer (polysaccharide)-based compounds.

Brewer's yeast polysaccharides - A review of their exquisite structural features and biomedical applications

Recent advances on brewer's yeast cell wall polysaccharides have unraveled exquisite structural features and diverse composition with (β1→3), (β1→6), (α1→4), (β1→4)-mix-linked glucans that are recognized to interact with different cell receptors and trigger specific biological responses. Herein, a comprehensive showcase of structure-biofunctional relationships between yeast polysaccharides and their biological targets is highlighted, with a focus on polysaccharide features that govern the biomedical activity. The insolubility of β-glucans is a crucial factor for binding and activation of Dectin-1 receptor, operating as adjuvants of immune responses. Contrarily, soluble low molecular weight β-glucans have a strong inhibition of reactive oxygen species production, acting as antagonists of Dectin-1 mediated signaling. Soluble glucan-protein moieties can also act as antitumoral agents. The balance between mannoproteins-TLR2 and β-glucans-Dectin-1 receptors-activation is crucial for osteogenesis. Biomedical applications value can also be obtained from yeast microcapsules as oral delivery systems, where highly branched (β1→6)-glucans lead to higher receptor affinity.

Assessment of the electrical penetration of cell membranes using four-frequency impedance cytometry

The electrical penetration of the cell membrane is vital for determining the cell interior via impedance cytometry. Herein, we propose a method for determining the conductivity of the cell membrane through the tilting levels of impedance pulses. When electrical penetration occurs, a high-frequency current freely passes through the cell membrane; thus, the intracellular distribution can directly act on the high-frequency impedance pulses. Numerical simulation shows that an uneven intracellular component distribution can affect the tilting levels of impedance pulses, and the tilting levels start increasing when the cell membrane is electrically penetrated. Experimental evidence shows that higher detection frequencies (>7 MHz) lead to a wider distribution of the tilting levels of impedance pulses when measuring cell populations with four-frequency impedance cytometry. This finding allows us to determine that a detection frequency of 7 MHz is able to pass through the membrane of Euglena gracilis (E. gracilis) cells. Additionally, we provide a possible application of four-frequency impedance cytometry in the biomass monitoring of single E. gracilis cells. High-frequency impedance (≥7 MHz) can be applied to monitor these biomass changes, and low-frequency impedance (<7 MHz) can be applied to track the corresponding biovolume changes. Overall, this work demonstrates an easy determination method for the electrical penetration of the cell membrane, and the proposed platform is applicable for the multiparameter assessment of the cell state during cultivation.

Probing the Biogenesis of Polysaccharide Granules in Algal Cells at Sub-Organellar Resolution via Raman Microscopy with Stable Isotope Labeling

Phototrophs assimilate CO₂ into organic compounds that accumulate in storage organelles. Elucidation of the carbon dynamics of storage organelles could enhance the production efficiency of valuable compounds and facilitate the screening of strains with high photosynthetic activity. To comprehensively elucidate the carbon dynamics of these organelles, the intraorganellar distribution of the carbon atoms that accumulate at specific time periods should be probed. In this study, the biosynthesis of polysaccharides in storage organelles was spatiotemporally probed via stimulated Raman scattering (SRS) microscopy using a stable isotope (¹³C) as the tracking probe. Paramylon granules (a storage organelle of β-1,3-glucan) accumulated in a unicellular photosynthetic alga, Euglena gracilis, were investigated as a model organelle. The carbon source of the culture medium was switched from NaH¹²CO₃ to NaH¹³CO₃ during the production of the paramylon granules; this resulted in the distribution of the ¹²C and ¹³C constituents in the granules, so that the biosynthetic process could be tracked. Taking advantage of high-resolution SRS imaging and label switching, the localization of the ¹²C and ¹³C constituents inside a single paramylon granule could be visualized in three dimensions, thus revealing the growth process of paramylon granules. We propose that this method can be used for comprehensive elucidation of the dynamic activities of storage organelles.

Fermentation profile, cholesterol-reducing properties and chemopreventive potential of β-glucans from Levilactobacillus brevis and Pediococcus claussenii - a comparative study with β-glucans from different sources

The aim of the present study was to investigate whether β-glucans obtained from the lactic acid bacteria (LAB) Levilactobacillus (L.) brevis and Pediococcus (P.) claussenii exhibit similar physiological effects such as cholesterol-binding capacity (CBC) as the structurally different β-glucans from oat, barley, and yeast as well as curdlan. After in vitro fermentation, fermentation supernatants (FSs) and/or -pellets (FPs) were analyzed regarding the concentrations of short-chain fatty acids (SCFAs), ammonia, bile acids, the relative abundance of bacterial taxa and chemopreventive effects (growth inhibition, apoptosis, genotoxicity) in LT97 colon adenoma cells. Compared to other glucans, the highest CBC was determined for oat β-glucan (65.9 ± 8.8 mg g^-1, p < 0.05). Concentrations of SCFA were increased in FSs of all β-glucans (up to 2.7-fold). The lowest concentrations of ammonia (down to 0.8 ± 0.3 mmol L^-1) and bile acids (2.5-5.2 μg mL^-1) were detected in FSs of the β-glucans from oat, barley, yeast, and curdlan. The various β-glucans differentially modulated the relative abundance of bacteria families and reduced the Firmicutes/Bacteroidetes ratio. Treatment of LT97 cells with the FSs led to a significant dose-dependent growth reduction and increase in caspase-3 activity without exhibiting genotoxic effects. Though the different β-glucans show different fermentation profiles as well as cholesterol- and bile acid-reducing properties, they exhibit comparable chemopreventive effects.

High-cell-density cultivation of the flagellate alga Poterioochromonas malhamensis for biomanufacturing the water-soluble β-1,3-glucan with multiple biological activities

The microalga Poterioochromonas malhamensis was found to be capable of accumulating the storage β-1,3-glucan in soluble form under heterotrophic conditions. In this study, the highest biomass yield of 32.8 g L^-1 was achieved by combining the utilization of ammonium chloride as the nitrogen source, simultaneous addition of vitamins B1 and B12 and maintenance of pH at 6.0. Sugar profiling and nuclear magnetic resonance analysis indicated that the P. malhamensis β-1,3-glucan was composed of glucose with the β-(1 → 3) main chain and the β-(1 → 6) side chain. Under the optimal cultivation conditions, the cellular β-1,3-glucan content was up to 55% of the cell dry weight. Moreover, the P. malhamensis β-1,3-glucan could significantly promote the fin regeneration and improve the in vivo antioxidative activity of zebrafish. This study underpins the feasibility of culturing P. malhamensis under heterotrophic conditions for producing the highly water-soluble bioactive β-1,3-glucans for food and pharmaceutical applications.

Recent advances in enzymatic synthesis of β-glucan and cellulose

Bottom-up synthesis of β-glucans such as callose, fungal β-(1,3)(1,6)-glucan and cellulose, can create the defined compounds that are needed to perform fundamental studies on glucan properties and develop applications. With the importance of β-glucans and cellulose in high-profile fields such as nutrition, renewables-based biotechnology and materials science, the enzymatic synthesis of such relevant carbohydrates and their derivatives has attracted much attention. Here we review recent developments in enzymatic synthesis of β-glucans and cellulose, with a focus on progress made over the last five years. We cover the different types of biocatalysts employed, their incorporation in cascades, the exploitation of enzyme promiscuity and their engineering, and reaction conditions affecting the production as well as in situ self-assembly of (non)functionalised glucans. The recent achievements in the application of glycosyl transferases and β-1,4- and β-1,3-glucan phosphorylases demonstrate the high potential and versatility of these biocatalysts in glucan synthesis in both industrial and academic contexts.

Anti-Inflammatory Activities of Euglena gracilis Extracts

Dietary supplementation with nutrients able to control intestinal and systemic inflammation is of marketable interest. Indeed, gastrointestinal homeostasis plays a significant role in maintaining human health. In this setting, E. gracilis may sustain or promote human health, but the effects on the intestinal inflammatory milieu are not clear. In this study, we investigated the anti-inflammatory activity of E. gracilis and inferred possible mechanisms. Paramylon, crude, and fractionated extracts were obtained from E. gracilis grown in vitro. Phytoconstituents of the extracts were characterized using TLC and HPLC UV-Vis. The anti-inflammatory and antioxidant activities were investigated in primary human macrophages and an intestinal epithelial cell line (HT-29). The analysis of the extracts led to identifying β-carotene, neoxanthin, diadinoxanthin, canthaxanthin, and breakdown products such as pheophytins and pheophorbides. E. gracilis fractionated extracts reduced the production of tumor necrosis factor-α triggered by bacterial lipopolysaccharide (LPS) in the short and long terms. Pheophytin a and b and canthaxanthin increased the intracellular reducing potential and dampened the production of LPS-induced reactive oxygen species and lipid peroxidation, intracellular events usually involved in the perpetuation of chronic inflammatory disorders. This study rationalizes the role of specific extract fractions of E. gracilis in controlling LPS-driven intestinal inflammation.

Fortifying a meal with oyster mushroom powder beneficially affects postprandial glucagon-like peptide-1, non-esterified free fatty acids and hunger sensation in adults with impaired glucose tolerance: a double-blind randomized controlled crossover trial

Purpose

Impaired glucose tolerance (IGT) is a pathophysiological condition characterized by insulin resistance with known metabolic consequences such as postprandial hyperglycemia and hypertriglyceridemia. We hypothesized that fortifying a meal with mushrooms rich in β-glucans may diminish glucose and triglyceride responses by improving postprandial gastrointestinal hormone release.

Methods

In a randomized controlled crossover study, 22 subjects with IGT ingested a meal either enriched with 20 g powder (8.1 g β-glucans) of oven-dried Pleurotus ostreatus (enriched meal, EN) or without enrichment (control meal, CON). Blood was collected before and repeatedly within 4 h after the meal to determine AUC of glucose (primary outcome), insulin, triglycerides, non-esterified free fatty acids (NEFAs), glucagon-like peptide-1 (GLP-1), gastric inhibitory polypeptide (GIP) and ghrelin. Appetite sensations (hunger, satiety, fullness, and desire to eat) were assessed before and after meal consumption by visual analog scales.

Results

Postprandial glucose, insulin, triglycerides, GIP and ghrelin concentrations as well as the corresponding AUCs did not differ between EN and CON. NEFAs-AUC was 14% lower (P = 0.026) and GLP-1-AUC 17% higher (P = 0.001) after EN compared to CON. Appetite ratings did not differ between treatments, except for hunger (AUC 22% lower after EN vs. CON; P = 0.031).

Conclusion

The observed immediate postprandial metabolic changes indicate that an easily manageable fortification of a single meal with powder from dried oyster mushrooms as β-glucan source may improve postprandial metabolism. If the effect is preserved long term, this measure can diminish the risk for further development of overweight/obesity and type 2 diabetes in subjects with IGT.

Clinical trial registration

German Clinical Trial Register on 09/08/2018; trial-ID: DRKS00015244.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00394-021-02674-1.

Increasing the Production of β-Glucan from Saccharomyces carlsbergensis RU01 by Using Tannic Acid

In this study, we increased β-glucan production from brewer's yeast, Saccharomyces carlsbergensis RU01, by using tannic acid. High-pressure freezing and transmission electron microscopy (HPF-TEM) revealed that the yeast cell wall obtained from yeast malt (YM) medium supplemented with 0.1% w/v tannic acid was thicker than that of yeast cultured in YM medium alone. The production of β-glucan from S. carlsbergensis RU01 was optimized in 3% w/v molasses and 0.1% w/v diammonium sulfate (MDS) medium supplemented with 0.1% w/v tannic acid. The results showed that MDS medium supplemented with 0.1% w/v tannic acid significantly increased the dry cell weight (DCW), and the β-glucan production was 0.28±0.01% w/v and 11.99±0.04% w/w. Tannic acid enhanced the β-glucan content by up to 42.23%. β-Glucan production in the stirred tank reactor (STR) was 1.4-fold higher than that in the shake flask (SF) culture. Analysis of the β-glucan composition by Fourier transform infrared (FTIR) spectroscopy showed that the β-glucan of S. carlsbergensis RU01 cultured in MDS medium supplemented with 0.1% w/v tannic acid had a higher proportion of polysaccharide than that of the control. In addition, β-glucans from brewer's yeast can be used as prebiotic and functional foods for human health and in animal feed.

A Noninvasive Gut-to-Brain Oral Drug Delivery System for Treating Brain Tumors

Most orally administered drugs fail to reach the intracerebral regions because of the intestinal epithelial barrier (IEB) and the blood-brain barrier (BBB), which are located between the gut and the brain. Herein, an oral prodrug delivery system that can overcome both the IEB and the BBB noninvasively is developed for treating gliomas. The prodrug is prepared by conjugating an anticancer drug on β-glucans using a disulfide-containing linker. Following oral administration in glioma-bearing mice, the as-prepared prodrug can specifically target intestinal M cells, transpass the IEB, and be phagocytosed/hitchhiked by local macrophages (Mϕ). The Mϕ-hitchhiked prodrug is transported to the circulatory system via the lymphatic system, crossing the BBB. The tumor-overexpressed glutathione then cleaves the disulfide bond within the prodrug, releasing the active drug, improving its therapeutic efficacy. These findings reveal that the developed prodrug may serve as a gut-to-brain oral drug delivery platform for the well-targeted treatment of gliomas.

Novel Anti-Fungal d-Laminaripentaose-Releasing Endo-β-1,3-glucanase with a RICIN-like Domain from Cellulosimicrobium funkei HY-13

Endo-β-1,3-glucanase plays an essential role in the deconstruction of β-1,3-d-glucan polysaccharides through hydrolysis. The gene (1650-bp) encoding a novel, bi-modular glycoside hydrolase family 64 (GH64) endo-β-1,3-glucanase (GluY) with a ricin-type β-trefoil lectin domain (RICIN)-like domain from Cellulosimicrobium funkei HY-13 was identified and biocatalytically characterized. The recombinant enzyme (rGluY: 57.5 kDa) displayed the highest degradation activity for laminarin at pH 4.5 and 40 °C, while the polysaccharide was maximally decomposed by its C-terminal truncated mutant enzyme (rGluYΔRICIN: 42.0 kDa) at pH 5.5 and 45 °C. The specific activity (26.0 U/mg) of rGluY for laminarin was 2.6-fold higher than that (9.8 U/mg) of rGluYΔRICIN for the same polysaccharide. Moreover, deleting the C-terminal RICIN domain in the intact enzyme caused a significant decrease (>60%) of its ability to degrade β-1,3-d-glucans such as pachyman and curdlan. Biocatalytic degradation of β-1,3-d-glucans by inverting rGluY yielded predominantly d-laminaripentaose. rGluY exhibited stronger growth inhibition against Candida albicans in a dose-dependent manner than rGluYΔRICIN. The degree of growth inhibition of C. albicans by rGluY (approximately 1.8 μM) was approximately 80% of the fungal growth. The superior anti-fungal activity of rGluY suggests that it can potentially be exploited as a supplementary agent in the food and pharmaceutical industries.

β-Glucans as Dietary Supplement to Improve Locomotion and Mitochondrial Respiration in a Model of Duchenne Muscular Dystrophy

Duchenne muscular dystrophy (DMD) is a severe X-linked neuromuscular childhood disorder that causes progressive muscle weakness and degeneration. A lack of dystrophin in DMD leads to inflammatory response, autophagic dysregulation, and oxidative stress in skeletal muscle fibers that play a key role in the progression of the pathology. β-glucans can modulate immune function by modifying the phagocytic activity of immunocompetent cells, notably macrophages. Mitochondrial function is also involved in an important mechanism of the innate and adaptive immune responses, owing to high need for energy of immune cells. In the present study, the effects of 1,3-1,6 β-glucans on five-day-old non-dystrophic and dystrophic (sapje) zebrafish larvae were investigated. The effects of the sonication of β-glucans and the dechorionation of embryos were also evaluated. The results showed that the incidence of dystrophic phenotypes was reduced when dystrophic embryos were exposed to 2 and 4 mg L^-1 of 1,3-1,6 β-glucans. Moreover, when the dystrophic larvae underwent 8 mg L^-1 treatment, an improvement of the locomotor performances and mitochondrial respiration were observed. In conclusion, the observed results demonstrated that 1,3-1,6 β-glucans improve locomotor performances and mitochondrial function in dystrophic zebrafish. Therefore, for ameliorating their life quality, 1,3-1,6 β-glucans look like a promising diet supplement for DMD patients, even though further investigations are required.

β-glucan, "the knight of health sector": critical insights on physiochemical heterogeneities, action mechanisms and health implications

β-glucans, the class of biological response modifier has unceasing attention, not only for its immune stimulating but also for its role as prebiotics, modulator of physiological events etc. and is widely used in the treatment of cancer, diabetes, gastrointestinal disorders, cardiovascular diseases etc. However, β-glucan with different physiochemical properties is found to have discrete clinical functions and thus careful selection of the types of β-glucan plays pivotal role in providing significant and expected clinical outcome. Herein this review, we presented the factors responsible for diverse functional properties of β-glucan, their distinct mode of actions in regulating human health etc. Further, clinical aspects of different β-glucans toward the management of wound care, metabolic dysbiosis, fatty liver disorders and endurance training associated energy metabolism were compiled and exhibited in detail.