Euglena gracilis paramylon activates human lymphocytes by upregulating pro-inflammatory factors

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.

Transcriptome analysis of the effects of different carbon dioxide concentrations on paramylon accumulation in Euglena gracilis Z

Appropriate concentration of carbon dioxide (CO2) will promote algae growth and metabolism. Building upon this finding, the present study investigated the impact of different CO2 concentrations (5% and 20%) on the carbon sequestration capacity of E. gracilis through aeration culturing, employing a combination of physiological analyses and transcriptome analysis. The results demonstrated that under 5% CO2 concentration, the cell density of E. gracilis was 1.79 times higher than that achieved in an air culture condition, and the paramylon content of E. gracilis was found to be 6.18 times higher than that of the air group. Based on transcriptome analysis, the carbon metabolism of E. gracilis was discussed. Significant up-regulation expression of genes associated with carbon synthesis was validated by an increase in paramylon content. This study revealed that under 5% CO2 conditions, E. gracilis exhibited elevated growth rate and enhanced photosynthetic carbon assimilation efficiency.

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

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

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.

Euglena gracilis (Euglena) powder supplementation enhanced immune function through natural killer cell activity in apparently healthy participants: A randomized, double-blind, placebo-controlled trial

Euglena gracilis (Euglena) is a microalgae found in most freshwater environments that produces paramylon, an insoluble β-1,3-glucan linked to human immunity. We hypothesized that Euglena powder has effects on immune function in apparently healthy adults. The study included male or female volunteers between the ages of 20 and 70 years who had white blood cell counts ranging from 4 × 103/µL to 10 × 103/µL, a "severe" rating on the stress questionnaire from the Korea National Health and Nutrition Examination Survey, and at least 2 upper respiratory infections with cold-like symptoms in the previous year. Participants received either a placebo or 700 mg of Euglena powder daily for 8 weeks. The study measured natural killer cell activity, cytokine concentrations, and blood lipid profiles to confirm the immune effect of Euglena consumption. In conclusion, Euglena improved immunological function through natural killer cell activity. Safety assessment showed no significant changes in vital signs or clinical chemistry indicators, and there were no adverse events associated with Euglena consumption. Euglena supplementation may help boost the immune systems of healthy individuals.

β-Glucans in particulate and solubilized forms elicit varied immunomodulatory and apoptosis effects in teleost macrophages in a dosedependent manner

β-Glucans are a group of heterogeneous glucose polymers that possess immunomodulatory activities. The complex nature of their structures, uncertainty regarding the doses, and variable immune effects pose a challenge to comprehensive understanding. In this study, we investigated the immune responses and apoptosis effects in Nile tilapia (Oreochromis niloticus) head kidney macrophages (MФ) upon exposure to two β-Glucans (Paramylon and Laminarin) at low and high doses. Our results demonstrate that Paramylon elicits more robust immune responses than Laminarin, albeit with a dose-limiting effect. We also observed that the high-dose Paramylon induces apoptosis, whereas no such effect was detected in Laminarin treatment. Mechanistically, high-dose Paramylon activates the intrinsic apoptosis pathway, with significantly up-regulation of intrinsic apoptosis-related genes and impaired mitochondrial function. On the other hand, Laminarin triggers metabolic reprogramming in MФ, resulting in the enrichment of the metabolite α-Ketoglutarate, which protects the MФ from apoptosis. Overall, our findings highlight the importance of identifying the optimal dose range for β-Glucans, based on sources or structures, to achieve maximal immunomodulatory effects. These results have important implications for the design and optimization of β-Glucans-based drugs or adjuvants in immunotherapies.

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.

Polysaccharides-Naturally Occurring Immune Modulators

The prevention of disease and infection requires immune systems that operate effectively. This is accomplished by the elimination of infections and abnormal cells. Immune or biological therapy treats disease by either stimulating or inhibiting the immune system, dependent upon the circumstances. In plants, animals, and microbes, polysaccharides are abundant biomacromolecules. Due to the intricacy of their structure, polysaccharides may interact with and impact the immune response; hence, they play a crucial role in the treatment of several human illnesses. There is an urgent need for the identification of natural biomolecules that may prevent infection and treat chronic disease. This article addresses some of the naturally occurring polysaccharides of known therapeutic potential that have already been identified. This article also discusses extraction methods and immunological modulatory capabilities.

Gravity sedimentation of eukaryotic algae Euglena gracilis accelerated by ethanol cultivation

Euglena gracilis (E. gracilis) is a unicellular microalga with various applications in medicine, agriculture, aquaculture, health supplement, and jet fuel production. Euglena possibly solves population growth and exhaustion of fossil resources. Efficient cell harvesting is needed for the industry, and the gravity sedimentation method is low cost and does not require any equipment, although it has low efficiency. This study showed that the gravity sedimentation of E. gracilis cells is improved by cultivation in the presence of ethanol (EtOH). The gravity sedimentation of E. gracilis cells cultivated under 0.5% or 1.0% EtOH conditions was faster than that cultivated without EtOH. The mean calculated cell diameter was also found to be largest in cells cultivated under 0.5% or 1.0% EtOH conditions compared to that in cells cultivated without EtOH. Intracellular paramylon content, cell shapes, and motility differed between cells cultivated under 0.5% or 1.0% EtOH conditions and in the absence of EtOH. The results suggest that E. gracilis cultivation with EtOH leads to increased cell productivity, paramylon production, and efficient cell harvesting. KEY POINTS: • Euglena gracilis is an edible microalga producing value-added metabolites. • Ethanol addition upregulates E. gracilis growth and paramylon accumulation. • Gravity sedimentation is accelerated by ethanol-grown E. gracilis cells.

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 [...].

Structural characterization of Euglena gracilis polysaccharide and its in vitro hypoglycemic effects by alleviating insulin resistance

Diabetes mellitus, characterized by hyperglycemia and insulin resistance, is a disorder of the endocrine metabolic system which has emerged as a common chronic disease worldwide. Euglena gracilis polysaccharides have ideal development potential in the treatment of diabetes. However, their structure and bioactivity are largely unclear. A novel purified water-soluble polysaccharide (EGP-2A-2A) from E. gracilis with a molecular weight of 130.8 kDa consisted of xylose, rhamnose, galactose, fucose, glucose, arabinose, and glucosamine hydrochloride. The SEM image for EGP-2A-2A suggested a rough surface with the presence of globule-like protrusions. Methylation and NMR spectral analyses revealed that EGP-2A-2A was mainly composed of →6)-β-D-Galp-(1 → 2)-α-D-Glcp-(1 → 2)-α-L-Rhap-(1 → 3)-α-L-Araf-(1 → 6)-β-D-Galp-(1 → 3)-α-D-Araf-(1 → 3)-α-L-Rhap-(1 → 4)-β-D-Xylp-(1 → 6)-β-D-Galp-(1 → with complex branching structure. EGP-2A-2A significantly increased glucose consumption and glycogen content in IR-HeoG2 cells and modulates glucose metabolism disorders by regulating PI3K, AKT, and GLUT4 signaling pathways. EGP-2A-2A significantly suppressed TC, TG, and LDL-c levels, and enhanced that of HDL-c. EGP-2A-2A ameliorated abnormalities caused by disorders of glucose metabolism and the hypoglycemic activity of EGP-2A-2A may be mainly positively related to its high glucose content and the β-configuration in the main chain. These results suggested that EGP-2A-2A played an important role in alleviating disorders of glucose metabolism through insulin resistance and has the potential for development as a novel functional food with nutritional and health benefits.

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.

Characterization and Antibacterial Activities of Carboxymethylated Paramylon from Euglena gracilis

Paramylon from Euglena gracilis (EGP) is a polymeric polysaccharide composed of linear β-1,3 glucan. EGP has been proved to have antibacterial activity, but its effect is weak due to its water insolubility and high crystallinity. In order to change this deficiency, this experiment carried out carboxymethylated modification of EGP. Three carboxymethylated derivatives, C-EGP1, C-EGP2, and C-EGP3, with a degree of substitution (DS) of 0.14, 0.55, and 0.78, respectively, were synthesized by varying reaction conditions, such as the mass of chloroacetic acid and temperature. Fourier transform infrared spectroscopy (FTIR), gel permeation chromatography (GPC), and nuclear magnetic resonance (NMR) analysis confirmed the success of the carboxymethylated modification. The Congo red (CR) experiment, scanning electron microscopy (SEM), X-ray diffraction (XRD), and thermogravimetry (TG) were used to study the conformation, surface morphology, crystalline nature, and thermostability of the carboxymethylated EGP. The results showed that carboxymethylation did not change the triple helix structure of the EGP, but that the fundamental particles’ surface morphology was destroyed, and the crystallization area and thermal stability decreased obviously. In addition, the water solubility test and antibacterial experiment showed that the water solubility and antibacterial activity of the EGP after carboxymethylation were obviously improved, and that the water solubility of C-EGP1, C-EGP2, and C-EGP3 increased by 53.31%, 75.52%, and 80.96% respectively. The antibacterial test indicated that C-EGP3 had the best effect on Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), with minimum inhibitory concentration (MIC) values of 12.50 mg/mL and 6.25 mg/mL. The diameters of the inhibition zone of C-EGP3 on E. coli and S. aureus were 11.24 ± 0.15 mm and 12.05 ± 0.09 mm, and the antibacterial rate increased by 41.33% and 43.67%.

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.

Immunoenhancing Effects of Euglena gracilis on a Cyclophosphamide-Induced Immunosuppressive Mouse Model

In this study, the effects of the immune stimulator Euglena gracilis (Euglena) in cyclophosphamide (CCP)-induced immunocompromised mice were assessed. The key component β-1,3-glucan (paramylon) constitutes 50% of E. gracilis. Mice were orally administered Euglena powder (250 and 500 mg/kg body weight (B.W.)) or β-glucan powder (250 mg/kg B.W.) for 19 days. In a preliminary immunology experiment, ICR mice were intraperitoneally injected with 80 mg of CCP/kg B.W. during the final 3 consecutive days. In the main experiment, BALB/c mice were treated with CCP for the final 5 days. To evaluate the enhancing effects of Euglena on the immune system, mouse B.W., the spleen index, natural killer (NK) cell activity and mRNA expression in splenocytes lungs and livers were determined. To detect cytokine and receptor expression, splenocytes were treated with 5 μg/ml concanavalin A or 1 μg/ml lipopolysaccharide. The B.W. and spleen index were significantly increased and NK cell activity was slightly enhanced in all the experimental groups compared to the CCP group. In splenocytes, the gene expression levels of tumor necrosis factor-α, interferon-γ, interleukin (IL)-10, IL-6, and IL-12 receptor were increased in the E. gracilis and β-glucan groups compared to the CCP group, but there was no significant difference. Treatment with 500mg of Euglena/kg B.W. significantly upregulated dectin-1 mRNA expression in the lung and liver compared to the CCP group. These results suggest that Euglena may enhance the immune system by strengthening innate immunity through immunosuppression.

Optimization of SARS-CoV-2 Spike Protein Expression in the Silkworm and Induction of Efficient Protective Immunity by Inoculation With Alum Adjuvants

The newly emerged severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is causing a spread of coronavirus disease 2019 (COVID-19) globally. In order to end the COVID-19 pandemic, an effective vaccine against SARS-CoV-2 must be produced at low cost and disseminated worldwide. The spike (S) protein of coronaviruses plays a pivotal role in the infection to host cells. Therefore, targeting the S protein is one of the most rational approaches in developing vaccines and therapeutic agents. In this study, we optimized the expression of secreted trimerized S protein of SARS-CoV-2 using a silkworm-baculovirus expression vector system and evaluated its immunogenicity in mice. The results showed that the S protein forming the trimeric structure was the most stable when the chicken cartilage matrix protein was used as the trimeric motif and could be purified in large amounts from the serum of silkworm larvae. The purified S protein efficiently induced antigen-specific antibodies in mouse serum without adjuvant, but its ability to induce neutralizing antibodies was low. After examining several adjuvants, the use of Alum adjuvant was the most effective in inducing strong neutralizing antibody induction. We also examined the adjuvant effect of paramylon from Euglena gracilis when administered with the S protein. Our results highlight the effectiveness and suitable construct design of the S protein produced in silkworms for the subunit vaccine development against SARS-CoV-2.

Oral Administration of Water Extract from Euglena gracilis Alters the Intestinal Microbiota and Prevents Lung Carcinoma Growth in Mice

The antitumor effects of a partially purified water extract from Euglena gracilis (EWE) and EWE treated by boiling (bEWE) were evaluated using orthotopic lung cancer syngeneic mouse models with Lewis lung carcinoma (LLC) cells. Daily oral administration of either EWE or bEWE started three weeks prior to the inoculation of LLC cells significantly attenuated tumor growth as compared to the phosphate buffered saline (PBS) control, and the attenuation was further enhanced by bEWE. The intestinal microbiota compositions in both extract-treated groups were more diverse than that in the PBS group. Particularly, a decrease in the ratio of Firmicutes to Bacteroidetes and significant increases in Akkermansia and Muribaculum were observed in two types of EWE-treated groups. Fecal microbiota transplantation (FMT) using bEWE-treated mouse feces attenuated tumor growth to an extent equivalent to bEWE treatment, while tumor growth attenuation by bEWE was abolished by treatment with an antibiotic cocktail. These studies strongly suggest that daily oral administration of partially purified water extracts from Euglena gracilis attenuates lung carcinoma growth via the alteration of the intestinal microbiota.

Euglena gracilis and Its Aqueous Extract Constructed With Chitosan-Hyaluronic Acid Hydrogel Facilitate Cutaneous Wound Healing in Mice Without Inducing Excessive Inflammatory Response

Naturally occurring compounds isolated from the microalga Euglena gracilis, such as polysaccharide paramylon, exhibit antimicrobial, anti-viral, antitumor, and anti-inflammatory activities. Whether live E. gracilis cells and its aqueous extract accelerate burn wound healing remains to be investigated. In this study, live E. gracilis cells and its aqueous extract were mixed with chitosan-hyaluronic acid hydrogel (CS/HA) to form cell + CS/HA and extract + CS/HA, which were then smeared onto the deeply burned skin of mice. The efficacy of these mixtures in accelerating wound healing was assessed through wound size reduction measurement, histological and immunofluorescence analyses, and serum pro-inflammatory cytokine level (INF-γ, IL-1β, and IL-6) determination. The live E. gracilis cells and its aqueous extract were found to facilitate wound healing by enhancing re-epithelization and reducing fibroplasia without stimulating excessive inflammatory response. In conclusion, live E. gracilis cells and its aqueous extract can be potentially used to treat cutaneous wounds.

Immune Status and Hepatic Antioxidant Capacity of Gilthead Seabream Sparus aurata Juveniles Fed Yeast and Microalga Derived β-glucans

This work aimed to evaluate the effects of dietary supplementation with β-glucans extracted from yeast (Saccharomyces cerevisiae) and microalga (Phaeodactylum tricornutum) on gene expression, oxidative stress biomarkers and plasma immune parameters in gilthead seabream (Sparus aurata) juveniles. A practical commercial diet was used as the control (CTRL), and three others based on CTRL were further supplemented with different β-glucan extracts. One was derived from S. cerevisiae (diet MG) and two different extracts of 21% and 37% P. tricornutum-derived β-glucans (defined as Phaeo21 and Phaeo37), to give a final 0.06% β-glucan dietary concentration. Quadruplicate groups of 95 gilthead seabream (initial body weight: 4.1 ± 0.1 g) were fed to satiation three times a day for 8 weeks in a pulse-feeding regimen, with experimental diets intercalated with the CTRL dietary treatment every 2 weeks. After 8 weeks of feeding, all groups showed equal growth performance and no changes were found in plasma innate immune status. Nonetheless, fish groups fed β-glucans supplemented diets showed an improved anti-oxidant status compared to those fed CTRL at both sampling points (i.e., 2 and 8 weeks). The intestinal gene expression analysis highlighted the immunomodulatory role of Phaeo37 diet after 8 weeks, inducing an immune tolerance effect in gilthead seabream intestine, and a general down-regulation of immune-related gene expression. In conclusion, the results suggest that the dietary pulse administration of a P. tricornutum 37% enriched-β-glucans extract might be used as a counter-measure in a context of gut inflammation, due to its immune-tolerant and anti-oxidative effects.

Paramylon extracted from Euglena gracilis EOD-1 augmented the expression of SIRT1

Euglena gracilis, a type of microalgae, contains several nutrients and accumulates paramylon, a β-1,3-glucan. In recent studies, paramylon has shown to exhibit various activities including immunomoduratory and hepatoprotective effects. In the present study, using an in vitro cell culture system, we aimed to determine whether paramylon derived from the E. gracilis EOD-1 strain, which produces large amounts of paramylon, can augment SIRT1 expression in epidermal cells via activating gut–skin interactions. Results showed that paramylon augmented the expression of SIRT1 in Caco-2 cells, a human intestinal cell line. Furthermore, microarray analysis of Caco-2 cells treated with paramylon showed that paramylon activates epidermal cells through inducing the secretion of factors from intestinal cells. Then, we focused on skin cells as target cells of paramylon-activated intestinal cells. Results showed that secretory factors from Caco-2 cells treated with paramylon augmented the expression of SIRT1 in HaCaT cells, a human keratinocyte cell line, and that expression level of genes related to the growth and maintenance of epidermal cells were significantly changed in Caco-2 cells treated with paramylon as evidenced by microarray analysis. All these results suggest that paramylon can activate epidermal cells by inducing the production of secretory factors from intestinal cells.

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.

Isolation and Characterization of Euglena gracilis-Associated Bacteria, Enterobacter sp. CA3 and Emticicia sp. CN5, Capable of Promoting the Growth and Paramylon Production of E. gracilis under Mixotrophic Cultivation

Euglena gracilis produces paramylon, which is a feedstock for high-value functional foods and nutritional supplements. The enhancement of paramylon productivity is a critical challenge. Microalgae growth-promoting bacteria (MGPB) can improve microalgal productivity; however, the MGPB for E. gracilis remain unclear. This study isolated bacteria capable of enhancing E. gracilis growth and paramylon production under mixotrophic conditions. Enterobacter sp. CA3 and Emticicia sp. CN5 were isolated from E. gracilis grown with sewage-effluent bacteria under mixotrophic conditions at pH 4.5 or 7.5, respectively. In a 7-day E. gracilis mixotrophic culture with glucose, CA3 increased E. gracilis biomass and paramylon production 1.8-fold and 3.5-fold, respectively (at pH 4.5), or 1.9-fold and 3.5-fold, respectively (at pH 7.5). CN5 increased E. gracilis biomass and paramylon production 2.0-fold and 4.1-fold, respectively (at pH 7.5). However, the strains did not show such effects on E. gracilis under autotrophic conditions without glucose. The results suggest that CA3 and CN5 promoted both E. gracilis growth and paramylon production under mixotrophic conditions with glucose at pH 4.5 and 7.5 (CA3) or pH 7.5 (CN5). This study also provides an isolation method for E. gracilis MGPB that enables the construction of an effective E. gracilis–MGPB-association system for increasing the paramylon yield of E. gracilis.

β-1,3-Glucan from Euglena gracilis as an immunostimulant mediates the antiparasitic effect against Mesanophrys sp. on hemocytes in marine swimming crab (Portunus trituberculatus)

β-1,3-glucans, natural polysaccharide groups, exert immunomodulatory effects to improve the innate response and disease resistance in aquatic species and mammals. However, this β-glucan stimulant is yet to be assayed in swimming crab (Portunus trituberculatus) hemocytes. In this study, we explored the immunomodulatory effect of β-1,3-glucans (derived from Euglena gracilis) via in vitro 24 h stimulation assays in swimming crab hemocytes. We found that this algal β-1,3-glucans in crab hemocytes significantly elevated cellular enzymes related parameters, including phenoloxidase (PO), lysozyme, acid phosphatase (ACP) activities, and superoxide anion generation (O₂^-) rate both at intracellular (P < 0.05) and extracellular (P < 0.05) levels. Besides, alkaline phosphatase (AKP) in hemocytes exhibited no significant differences across the groups (P > 0.05). β-glucan significantly influenced (P < 0.05) the activities of the antioxidant enzyme, superoxide dismutase (SOD) in hemocytes. Moreover, the relative mRNA expression of numerous immune-related genes, including proPO, TLR-2, Alf-1, NOX, Lysozyme, Crustin-1, and Cuznsod, was significantly higher stimulated hemocytes than in control (P < 0.05). We also reported the dose-dependent antiparasitic activity against Mesanophyrs sp., in stimulated hemocytes than in the control (P < 0.05). The present study collectively demonstrated that β-glucan potentially stimulates innate immunity by elevating cellular enzyme responses and up-regulating the mRNA expression of genes associated with crab innate immunity. Thus, β-glucan is a promising immunostimulant for swimming crab farming in crustaceans aquaculture.

A strategic approach to apply bacterial substances for increasing metabolite productions of Euglena gracilis in the bioreactor

Bacterial extracellular polymeric substances (EPS) are promising materials that have a role in enhancing growth, metabolite production, and harvesting efficiency. However, the validity of the EPS effectiveness in scale-up cultivation of microalgae is still unknown. Therefore, in order to verify whether the bacterial metabolites work in the scale-up fermentation of microalgae, we conducted a bioreactor fermentation following the addition of bacterial EPS derived from the marine bacterium, Pseudoalteromonas sp., to Euglena gracilis. Various culture strategies (i.e., batch, glucose fed-batch, and glucose and EPS fed-batch) were conducted to maximize metabolite production of E. gracilis in scale-up cultivation. Consequently, biomass and paramylon concentrations in the continuous glucose and EPS-treated culture were enhanced by 3.0-fold and 4.2-fold (36.1 ± 1.4 g L^-1 and 25.6 ± 0.1 g L^-1), respectively, compared to the non-treated control (12.0 ± 0.3 g L^-1 and 6.1 ± 0.1 g L^-1). Also, the supplementation led to the enhanced concentrations of α-tocopherols and total fatty acids by 3.7-fold and 2.8-fold, respectively. The harvesting efficiency was enhanced in EPS-supplemented cultivation due to the flocculation of E. gracilis. To the best of our knowledge, this is the first study that verifies the effect of bacterial EPS in scale-up cultivation of microalgae. Also, our results showed the highest paramylon productivity than any other previous reports. The results obtained in this study showed that the scale-up cultivation of E. gracilis using bacterial EPS has the potential to be used as a platform to guide further increases in scale and in the industrial environment. KEY POINTS: Effect of EPS on Euglena gracilis fermentation was tested in bioreactor scale. EPS supplement was effective for the paramylon, α-tocopherol, and lipid production. EPS supplement induced the flocculation of E. gracilis.

Microalgae as feed ingredients: recent developments on their role in immunomodulation and gut microbiota of aquaculture species

Microalgae are rapidly evolving alternative ingredients in food and feed. Desirable nutritional and functional qualities make them high potential sources of feed ingredients. Certain microalgae species are known to accumulate large amounts of protein, containing all essential amino acids while some species contain essential fatty acids and bioactive compounds hence offering several possible health benefits. However, successful inclusion of microalgae-based products in feed requires a clear understanding of physiological responses and microbiota of animals receiving microalgae diets. In this review, key microalgae-based feed ingredients and their effect on gut microbiome and immunomodulatory responses of microalgae fed animals, with a focus on aquatic species will be discussed.

Unconventional high-value products from microalgae: A review

Microalgae have gained significant importance in biotechnology development, providing valuable goods and services in multiple applications. Although there is a rising market for most of these applications, the incorporation and introduction of microalgae into new venues will extend in the near future. These advances are due to the vast biodiversity of microalgal species, recent genetic engineering tools, and culture techniques. There are three main possible approaches for novel algal compounds from: (1) recently isolated yet less known microalgae; (2) selectively stressed conditions; and (3) enzymatically adjusted compounds from conventional molecules. All these approaches can be combined in a specific manner. This review discusses the opportunities, potential and limitations of introducing novel microalgae-based products, and how the recent technologies can be deployed to make these products financially viable. To give an outlook to the future, an analysis of the developments and predicted future market that further enlarge the promise of cultivating microalgae for commercial purposes are considered.

Scenedesmus acutus extracellular polysaccharides produced under increased concentration of sulphur and phosphorus exhibited enhanced proliferation of peripheral blood mononuclear cells

Exopolysaccharides (EPS) isolated from microalgae are promising immune cell proliferation agents, that could be potentially used as immunostimulants. In the current study, Scenedesmus acutus (S. acutus) was grown under varying nutrient (sulphur and phosphorus) concentrations to enhance the EPS production, and the isolated EPS were assessed for their effect on cell proliferation using peripheral blood mononuclear cells (PBMC). Five different concentrations of MgSO₄ (0, 0.25, 0.5, 1.0 and 1.25 g/L) and K₂HPO₄ (0, 0.2, 0.6, 0.8 and 1.0 g/L) were taken as compared to the normal culture conditions (0.75 g/L MgSO₄ and 0.4 g/L K₂HPO₄) with the intention to enrich EPS secretion. LC–MS, FTIR and NMR analysis revealed that isolated EPS have the characteristic spectrum of hetero-polysaccharides (octa-saccharides). Immunostimulatory property of EPS was demonstrated by their ability to augment PBMC proliferation as measured by MTT assay. Further, increase in the glucose content and proliferative index was observed for EPS obtained under higher concentrations of MgSO₄ (1 and 1.25 g/L) and K₂HPO₄ (0.6 and 0.8 g/L) relative to normal culture conditions. Effects of the generated EPS under varying concentration of MgSO₄ (r = 0.84–0.99) and K₂HPO₄ (r = 0.76–0.97) remained strongly correlated with cell count, chlorophyll content, total biomass, glucose, proliferative index and its scavenging activity. Collectively, our data not only showed that EPS generated by S. acutus under higher concentration of K₂HPO₄ and MgSO₄ possess improved immunostimulatory properties, but also provides convincing evidence towards nutritional optimization of alga for enhanced EPS production with better bioactivities.

Carotenoid Extract Derived from Euglena gracilis Overcomes Lipopolysaccharide-Induced Neuroinflammation in Microglia: Role of NF-κB and Nrf2 Signaling Pathways

Activation of microglia results in the increased production and release of a series of inflammatory and neurotoxic mediators, which play essential roles in structural and functional neuronal damage and in the development and progression of a number of neurodegenerative diseases. The microalga Euglena gracilis (Euglena), rich in vitamins, minerals, and other nutrients, has gained increasing attention due to its antimicrobial, anti-viral, antitumor, and anti-inflammatory activities. In particular, anti-inflammatory properties of Euglena could exert neuroprotective functions in different neurodegenerative diseases related to inflammation. However, the mechanisms underlying the anti-inflammatory effect of Euglena are not fully understood. In this study, we investigated whether Euglena could attenuate microglia activation and we also studied the mechanism of its anti-inflammatory activity. Our results showed that non-cytotoxic concentrations of a Euglena acetone extract (EAE) downregulated the mRNA expression levels and release of pro-inflammatory mediators, including NO, IL-1β, and TNF-α in LPS-stimulated microglia. EAE also significantly blocked the LPS-induced nuclear translocation of NF-κB p65 subunit and increased the mRNA expression of nuclear factor erythroid 2–related factor (Nrf2) and heme oxygenase-1 (HO-1). Furthermore, the release of pro-inflammatory mediators and NF-κB activation were also blocked by EAE in the presence of ML385, a specific Nrf2 inhibitor. Together, these results show that EAE overcomes LPS-induced microglia pro-inflammatory responses through downregulation of NF-κB and activation of Nrf2 signaling pathways, although the two pathways seem to get involved in an independent manner.

Heracleum moellendorffii root extracts exert immunostimulatory activity through TLR2/4-dependent MAPK activation in mouse macrophages, RAW264.7 cells

Heracleum moellendorffii (H. moellendorffii) is a family of Umbelliferae and has long been used for food and medicinal purposes. However, the immune-enhancing activity of H. moellendorffii has not been studied. Thus, we evaluated in vitro immune-enhancing activity of H. moellendorffii through macrophage activation using RAW264.7 cells. Heracleum moellendorffii Root extracts (HMR) increased the production of immunomodulators such as NO, iNOS, IL-1β, IL-6 IL-12, TNF-α, and MCP-1 and activated phagocytosis in RAW264.7 cells. Inhibition of TLR2 and TLR4 reduced the production of immunomodulators induced by HMR. Inhibition of MAPK signaling attenuated the production of immunomodulators induced by HMR, but inhibitions of NF-κB or PI3K/AKT signaling did not affect HMR-mediated production of immunomodulators. HMR activated MAPK signaling pathway, and activation of MAPK signaling pathways by HMR was reversed by TLR2 and TLR4 inhibition. Based on the results of this study, HMR is thought to activate macrophages through the production of immunomodulators and phagocytosis activation through TLR2/4-dependent MAPK signaling pathway. Therefore, it is thought that HMR has the potential to be used as an agent for enhancing immunity.

Isolation and characterization of a motility-defective mutant of Euglena gracilis

Euglena gracilis is a green photosynthetic microalga that swims using its flagellum. This species has been used as a model organism for over half a century to study its metabolism and the mechanisms of its behavior. The development of mass-cultivation technology has led to E. gracilis application as a feedstock in various products such as foods. Therefore, breeding of E. gracilis has been attempted to improve the productivity of this feedstock for potential industrial applications. For this purpose, a characteristic that preserves the microalgal energy e.g., reduces motility, should be added to the cultivars. The objective of this study was to verify our hypothesis that E. gracilis locomotion-defective mutants are suitable for industrial applications because they save the energy required for locomotion. To test this hypothesis, we screened for E. gracilis mutants from Fe-ion-irradiated cell suspensions and established a mutant strain,M 3 - ZFeL, which shows defects in flagellum formation and locomotion. The mutant strain exhibits a growth rate comparable to that of the wild type when cultured under autotrophic conditions, but had a slightly slower growth under heterotrophic conditions. It also stores 1.6 times the amount of paramylon, a crystal of β-1,3-glucan, under autotrophic culture conditions, and shows a faster sedimentation compared with that of the wild type, because of the deficiency in mobility and probably the high amount of paramylon accumulation. Such characteristics make E. gracilis mutant cells suitable for cost-effective mass cultivation and harvesting.

Euglena Gracilis and β-Glucan Paramylon Induce Ca2+ Signaling in Intestinal Tract Epithelial, Immune, and Neural Cells

The intestinal tract contains over half of all immune cells and peripheral nerves and manages the beneficial interactions between food compounds and the host. Paramylon is a β-1,3-glucan storage polysaccharide from Euglena gracilis (Euglena) that exerts immunostimulatory activities by affecting cytokine production. This study investigated the signaling mechanisms that regulate the beneficial interactions between food compounds and the intestinal tract using cell type-specific calcium (Ca²⁺) imaging in vivo and in vitro. We successfully visualized Euglena- and paramylon-mediated Ca²⁺ signaling in vivo in intestinal epithelial cells from mice ubiquitously expressing the Yellow Cameleon 3.60 (YC3.60) Ca²⁺ biosensor. Moreover, in vivo Ca²⁺ imaging demonstrated that the intraperitoneal injection of both Euglena and paramylon stimulated dendritic cells (DCs) in Peyer’s patches, indicating that paramylon is an active component of Euglena that affects the immune system. In addition, in vitro Ca²⁺ imaging in dorsal root ganglia indicated that Euglena, but not paramylon, triggers Ca²⁺ signaling in the sensory nervous system innervating the intestine. Thus, this study is the first to successfully visualize the direct effect of β-1,3-glucan on DCs in vivo and will help elucidate the mechanisms via which Euglena and paramylon exert various effects in the intestinal tract.

Immune activation of murine RAW264.7 macrophages by sonicated and alkalized paramylon from Euglena gracilis

BACKGROUND

Euglena is a new super health food resource that is rich in the natural polysaccharide paramylon, a linear β-1,3-glucan with various biological activities including activity on the immune system in different cell lines and animals. Despite these reports, the immune regulation mechanism of paramylon is still unclear.

RESULTS

We investigate the signaling pathways paramylon impacts in immune macrophages. In RAW264.7 macrophages, sonicated and alkalized paramylon oligomers up-regulated inducible nitric oxide synthase (iNOS) and increased secretion of nitric oxide (NO), interleukin (IL)-6 and tumor necrosis factor (TNF)-α, in a concentration-dependent manner. In addition, paramylon activated the nuclear factor-κB(NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways and inhibiting these pathways attenuated the paramylon-induced secretion of the above immune-mediators.

CONCLUSIONS

These results demonstrate that Euglena gracilis paramylon modulates the immune system via activation of the NF-κB and MAPK signaling pathways and thus has potential therapeutic benefits.

Water extract from Euglena gracilis prevents lung carcinoma growth in mice by attenuation of the myeloid-derived cell population

The partially purified water extract from Euglena gracilis (EWE) was evaluated for its antitumor and immunomodulatory effects in cell cultures and in a mouse orthotopic lung carcinoma allograft model. In two-dimensional cell culture, the EWE treatment inhibited cell growth of both murine Lewis lung carcinoma (LLC) and human lung carcinoma cells (A549 and H1299) in a dose- and time-dependent manner. In contrast, the growth of mouse bone marrow cells (BMCs), but not mouse splenocytes (SPLs), was stimulated by the treatment with EWE. In three-dimensional spheroid culture, spheroid growth of LLC cells was significantly attenuated by EWE treatment. In a mouse LLC orthotopic allograft model, pretreatment with EWE (150-200 mg/kg/day, via drinking water) three weeks prior to the LLC cell inoculation, but not post-treatment after LLC cell inoculation, significantly attenuated the growth of LLC tumors in immunocompetent syngeneic mouse lung. This tumor growth attenuation coincided with a significant decrease in the population of myeloid-derived cells, primarily neutrophils. Flow cytometric analysis revealed that the EWE treatment significantly attenuated growth of granulocytic myeloid-derived suppressor cells (gMDSC) in BMCs and that this decrease was due to induction of gMDSC-specific apoptosis and differentiation of monocytic MDSCs (mMDSC) to macrophages. The present study provides evidence that EWE pretreatment inhibits lung carcinoma growth mainly by stimulating host antitumor immunity through attenuation of growth of gMDSCs and decreasing the number of peripheral granulocytes. This study suggests that the partially purified extract derived from Euglena gracilis contains significant bioactive materials that prevent lung carcinoma growth.

Microalgae with Immunomodulatory Activities

Microalgae are photosynthetic microorganisms adapted to live in very different environments and showing an enormous biochemical and genetic diversity, thus representing an excellent source of new natural products with possible applications in several biotechnological sectors. Microalgae-derived compounds have shown several properties, such as anticancer, antimicrobial, anti-inflammatory, and immunomodulatory. In the last decade, compounds stimulating the immune system, both innate immune response and adaptive immune response, have been used to prevent and fight various pathologies, including cancer (cancer immunotherapy). In this review we report the microalgae that have been shown to possess immunomodulatory properties, the cells and the cellular mediators involved in the mechanisms of action and the experimental models used to test immunostimulatory activities. We also report information on fractions or pure compounds from microalgae identified as having immunostimulatory activity. Given the increasing interest in microalgae as new eco-friendly source of bioactive compounds, we also discuss their possible role as source of new classes of promising drugs to treat human pathologies.

Effect of a Euglena gracilis Fermentate on Immune Function in Healthy, Active Adults: A Randomized, Double-Blind, Placebo-Controlled Trial

Euglena gracilis produce high amounts of algal β-1,3-glucan, which evoke an immune response when consumed. This study investigated the effect of supplementation with a proprietary Euglena gracilis fermentate (BG), containing greater than 50% β-1,3-glucan, on immune function as measured by self-reported changes in upper respiratory tract infection (URTI) symptoms. Thirty-four healthy, endurance-trained participants were randomized and received either 367 mg of BG or placebo (PLA) for 90 days. Symptoms were assessed by the 24-item Wisconsin Upper Respiratory Symptom Survey and safety via clinical chemistry, hematology, vitals, and adverse event reporting. Participants supplemented with BG over 90 days reported fewer sick days (BG: 1.46 ± 1.01; PLA: 4.79 ± 1.47 days; p = 0.041), fewer URTI symptoms (BG: 12.62 ± 5.92; PLA: 42.29 ± 13.17; p = 0.029), fewer symptom days (BG: 5.46 ± 1.89; PLA: 15.43 ± 4.59 days; p = 0.019), fewer episodes (BG: 2.62 ± 0.67; PLA: 4.79 ± 0.67; p = 0.032), and lower global severity measured as area under curve for URTI symptoms (BG: 17.50 ± 8.41; PLA: 89.79 ± 38.92; p = 0.0499) per person compared to placebo. Sick days, symptoms, and global severity were significantly (p < 0.05) fewer over 30 days in the BG group compared to PLA. All safety outcomes were within clinically normal ranges. The study provides evidence that supplementation with a proprietary Euglena gracilis fermentate containing greater than 50% β-1,3-glucan may reduce and prevent URTI symptoms, providing immune support and protecting overall health.

Paramylon, a Potent Immunomodulator from WZSL Mutant of Euglena gracilis

β-glucans, heterogeneous glucose polymers present in many organisms, have the capability to activate the innate immune system. Efficacy of activation depends on purity of the compound, molecular structure, polymerization degree, and source. One of the purest forms of crystallized β-(1–3)-glucan present in nature is the paramylon extracted from the WZSL non-chloroplastic mutant of Euglena gracilis, which can be processed to produce linear nanofibers capable of interacting with specific receptors present on cell membranes. The effects of these nanofibers, already investigated on plants, animals, and humans, will be analyzed.

Effects of Euglena gracilis EOD-1 Ingestion on Salivary IgA Reactivity and Health-Related Quality of Life in Humans

Euglena gracilis EOD-1, a microalgal strain known for high yields of the β-1, 3-glucan paramylon, is suggested to function as a dietary fiber and enhance immunity. Here, we aimed to investigate the effects of E. gracilis EOD-1 biomass (EOD1BM) ingestion on immunoglobulin A (IgA) antibody titers in saliva, its reactivity, and the health-related quality of life (QOL) in humans. Reacting human immunoglobulin preparations and saliva with paramylon granules revealed the presence of anti-paramylon antibodies in the blood and saliva. We conducted a placebo-controlled, double-blind, crossover study involving 13 healthy subjects who ingested the placebo or EOD1BM for 4 weeks. Saliva was collected from each subject before and after ingestion, and IgA titers and E. gracilis EOD-1 paramylon (EOD1PM) reactivity were compared. In the EOD1BM Ingestion group, the anti-EOD1PM IgA content and titer increased after EOD1BM ingestion. No such change was observed in the Placebo group. Furthermore, the health-related QOL, especially mental health, increased in the EOD1BM Ingestion group. Thus, EOD1BM ingestion led to the production of paramylon (PM)-specific IgA antibody and increased salivary IgA antibody titers. We demonstrate that EOD1BM ingestion enhanced the immunity in the mucosal surface, evoked an antigen-specific response, and increased the health-related QOL, thereby contributing to health improvement.

Bioproducts From Euglena gracilis: Synthesis and Applications

In recent years, the versatile phototrophic protist Euglena gracilis has emerged as an interesting candidate for application-driven research and commercialisation, as it is an excellent source of dietary protein, pro(vitamins), lipids, and the β-1,3-glucan paramylon only found in euglenoids. From these, paramylon is already marketed as an immunostimulatory agent in nutraceuticals. Bioproducts from E. gracilis can be produced under various cultivation conditions discussed in this review, and their yields are relatively high when compared with those achieved in microalgal systems. Future challenges include achieving the economy of large-scale cultivation. Recent insights into the complex metabolism of E. gracilis have highlighted unique metabolic pathways, which could provide new leads for product enhancement by genetic modification of the organism. Also, development of molecular tools for strain improvement are emerging rapidly, making E. gracilis a noteworthy challenger for microalgae such as Chlorella spp. and their products currently on the market.

Particulate and solubilized β-glucan and non-β-glucan fractions of Euglena gracilis induce pro-and anti-inflammatory innate immune cell responses and exhibit antioxidant properties

Purpose

The purpose of this work was to determine the pro-and anti-inflammatory properties of the single-cell organism Euglena gracilis (EG) and various fractions of its whole biomass.

Methods

Heterotrophically grown EG was tested, along with its aqueous fraction (E-AQ), the intact linear β-glucan paramylon granules (PAR), and alkaline-solubilized paramylon. Peripheral blood mononuclear cell cultures were treated with the test products and analyzed for a variety of cellular responses. Immune cell activation was evaluated by flow cytometry detection of CD69 levels on CD3^-CD56⁺ NK cells, CD3⁺CD56⁺ NKT cells, and monocytes, and cytokines were analyzed from the cell culture supernatants. Antioxidant capacity was measured by Folin-Ciocalteu assay and cellular antioxidant protection and MTT assays.

Results

EG and E-AQ were the most effective in driving immune cell responses as measured by CD69 upregulation on NK and NKT cells and proinflammatory (tumor necrosis factor, IL-6, IL-1β) cytokine production. None of the test products effectively stimulated monocyte. EG and PAR inhibited reactive oxygen species under conditions of oxidative stress. E-AQ contained antioxidants capable of providing cellular antioxidant protection from oxidative damage and protection of mitochondrial function under inflammatory conditions.

Conclusion

The effects of EG on immune function are only partially attributable to the content of the β-glucan, paramylon. The regulation of additional cellular responses, such a reactive oxygen species production and resistance to oxidative stress, is likely mediated by currently unknown molecules found in the EG cell.

Accelerated Wound Healing on the Skin Using a Film Dressing with β-Glucan Paramylon

BACKGROUND/AIM

β-Glucan has been shown to modulate immune system and potentially aid wound healing. A naturally-available β-glucan, paramylon, is available in the form of a film, which would be an ideal form to use in wound care. The aim of this study was to examine the therapeutic efficacy of paramylon film as a wound dressing.

MATERIALS AND METHODS

An acute wound was created on the skin of the posterior aspect of mice and wound healing was observed for 5 days. Mice were treated with either paramylon film or conventional cellulose film.

RESULTS

The time course of changes in wound size revealed that paramylon film dressing application leads to significantly faster wound contraction than conventional cellulose film. The dressing suppressed elevation of the inflammatory cytokines interferon gamma, interleukin-6, and vascular endothelial growth factor.

CONCLUSION

β-Glucan paramylon film can facilitate wound healing by inhibiting inflammatory aggression and has potential application as a novel wound dressing.

Toxicological assessment of Euglena gracilis strain Eu029 shows no adverse effects in vivo and in vitro

Euglena gracilis is a single-celled organism capable of photosynthesis and heterotrophy. Euglena sp. have long been studied in the laboratory for its metabolic pathways, cell motility, and ease of culture. The safety of E. gracilis strain eu029 (EG029) for use as a food ingredient was assessed in a bacterial reverse mutagenesis assay (Ames), rec assay, in vivo micronucleus assay, acute toxicity study in mice, 13-week toxicology in rats, and a teratology study in mice and rats. EG029 was not genotoxic. The No Observed Adverse Effect Level (NOAEL) in the 13-week study was greater than 1000 mg/kg/day, the highest dose tested. Teratogenicity studies did not find any defects in fetal development or effects to maternal health in rats at 1000 mg/kg/day, the highest dose tested.

The role of Euglena gracilis paramylon in modulating xylem hormone levels, photosynthesis and water-use efficiency in Solanum lycopersicum L

β-1,3-glucans such as paramylon act as elicitors in plants, modifying the hormonal levels and the physiological responses. Plant hormones affect all phases of the plant life cycle and their responses to environmental stresses, both biotic and abiotic. The aim of this study was to investigate the effects of a root treatment with Euglena gracilis paramylon on xylem hormonal levels, photosynthetic performance and dehydration stress in tomato (Solanum lycopersicum). Paramylon granules were processed to obtain the linear fibrous structures capable to interact with tomato cell membrane. Modulation of hormone levels (abscisic acid, jasmonic acid and salicylic acid) and related physiological responses such as CO₂ assimilation rate, stomatal and mesophyll conductance, intercellular CO₂ concentration, transpiration rate, water-use efficiency, quantum yield of photosystem II and leaf water potential were investigated. The results indicate a clear dose-dependent effect of paramylon on the hormonal content of xylem sap, photosynthetic performance and dehydration tolerance. Paramylon has the capability to enhance plant defense capacity against abiotic stress, such as drought, by modulating the conductance to CO₂ diffusion from air to the carboxylation sites and improving the water-use efficiency.