Selenized polysaccharides – Biosynthesis and structural analysis

Polysaccharides in fruits: Biological activities, structures, and structure-activity relationships and influencing factors-A review

Fruits are a rich source of polysaccharides, and an increasing number of studies have shown that polysaccharides from fruits have a wide range of biological functions. Here, we thoroughly review recent advances in the study of the bioactivities, structures, and structure-activity relationships of fruit polysaccharides, especially highlighting the structure-activity influencing factors such as extraction methods and chemical modifications. Different extraction methods cause differences in the primary structures of polysaccharides, which in turn lead to different polysaccharide biological activities. Differences in the degree of modification, molecular weight, substitution position, and chain conformation caused by chemical modification can all affect the biological activities of fruit polysaccharides. Furthermore, we summarize the applications of fruit polysaccharides in the fields of pharmacy and medicine, foods, cosmetics, and materials. The challenges and perspectives for fruit polysaccharide research are also discussed.

Microbial Polysaccharides Extracted from Different Mature Muds of the Euganean Thermal District Show Similar Anti-Inflammatory Activity In Vivo

The Euganean Thermal District, situated in North-East Italy, is one of Europe's largest and oldest thermal centres. The topical application of its therapeutic thermal muds is recognised by the Italian Health System as a beneficial treatment for patients suffering from arthro-rheumatic diseases. Polysaccharides produced by the mud microbiota have been recently identified as anti-inflammatory bioactive molecules. In this paper we analysed the efficacy of Microbial-Polysaccharides (M-PS) derived from mature muds obtained at different maturation temperatures, both within and outside the codified traditional mud maturation range. M-PSs were extracted from six mature muds produced by five spas of the Euganean Thermal District and investigated for their chemical properties, monosaccharide composition and in vivo anti-inflammatory potential, using the zebrafish model organism. Additionally, mature muds were characterized for their microbiota composition using Next-Generation Sequencing. The results showed that all M-PSs exhibit similar anti-inflammatory potential, referable to their comparable chemical composition. This consistency was observed despite changes in cyanobacteria populations, suggesting a possible role of the entire microbial community in shaping the properties of these biomolecules. These findings highlight the importance of scientific research in untangling the origins of the therapeutic efficacy of Euganean Thermal muds in the treatment of chronic inflammatory conditions.

Selenosugar, selenopolysaccharide, and putative selenoflavonoid in plants

Selenium (Se) is a naturally occurring essential micronutrient that is required for human health. Selenium supports cellular antioxidant defense and possesses bioeffects such as anti-inflammation, anti-cancer, anti-diabetic, and cardiovascular and liver protective effects arising from Se-enhanced cellular antioxidant activity. Past studies on Se have focused on elucidating Se speciation in foods, biofortification strategies to produce Se-enriched foods to address Se deficiency in the population, and the biochemical activities of Se in health. The bioavailability and toxicity of Se are closely correlated to its chemical forms and may exhibit varying effects on body physiology. Selenium exists in inorganic and organic forms, in which inorganic Se such as sodium selenite and sodium selenate is more widely available. However, it is a challenge for safe and effective supplementation considering inorganic Se low bioavailability and high cytotoxicity. Organic Se, by contrast, exhibits higher bioavailability and lower toxicity and has a more diverse composition and structure. Organic Se exists as selenoamino acids and selenoproteins, but recent research has provided evidence that it also exists as selenosugars, selenopolysaccharides, and possibly as selenoflavonoids. Different food categories contain various Se compounds, and their Se profiles vary significantly. Therefore, it is necessary to delineate Se speciation in foods to understand their impact on health. This comprehensive review documents our knowledge of the recent uncovering of the existence of selenosugars and selenopolysaccharides and the putative evidence for selenoflavonoids. The bioavailability and bioactivities of these food-derived organic Se compounds are highlighted, in addition to their composition, structural features, and structure-activity relationships.

A sulfated exopolysaccharide derived from Chlorella sp. exhibiting in vitro anti-α-D-Glucosidase activity

There is a great scientific curiosity to discover all environments sheltering microalgae, especially those with exceptional characteristics from coldest to hottest ones, the purpose remains to explore the potential of the native microalgae flora and the research for new bioactive compounds. This study aimed to isolate a polysaccharide-producing microalga from an extreme ecosystem and to evaluate its capacity to inhibit the α-D-glucosidase enzyme. Chlorella strain is isolated from hypersaline Lake in the Algerian desert. The exopolysaccharide extraction was performed by the concentration of free-cell supernatant in a rotary evaporator. The infrared analysis showed a characteristic footprint of carbohydrates with particular functional groups, such as sulfate. Gas chromatography-mass spectrometry has revealed a hetero-exopolysaccharide composed of galactose 35.75%, glucose 21.13%, xylose 16.81%, fructose 6.96%, arabinose 5.10%, and glucuronic acid 2.68%. The evaluation of the anti-hyperglycemic activity demonstrated a significant α-D-glucosidase inhibition of 80.94 ± 0.01% at 10 mg mL-1 with IC50 equal to 4.31 ± 0.20 mg mL-1. This study opens a vast prospect to use exopolysaccharides as natural nutraceutical or food additive.

Structural characterization and ferroptosis-related immunomodulatory of a novel exopolysaccharide isolated from marine fungus Aspergillus medius

Marine fungal exopolysaccharides play a crucial role in immunoregulation. In this investigation, a novel polysaccharide was extracted from the culture medium of the marine fungus Aspergillus medius SCAU-236. Compositional analysis revealed a structure composed of glucose units with (1,4)-α-D-Glcp, (1,3,4)-β-D-Glcp, and (1,4,6)-α-D-Glcp, along with side chains of 1-α-D-Glcp linked to carbon 6 of (1,4,6)-α-D-Glcp and carbon 3 of (1,3,4)-β-D-Glcp. Functional evaluations on RAW264.7 macrophage cells demonstrated Aspergillus medius polysaccharide (ASMP)'s effects on cell proliferation, nitric oxide levels, and the secretion of TNF-α, IL-6, and IL-1β cytokines. Additionally, metabolomics indicated ASMP's potential to modulate macrophage immune function by impacting key regulatory molecules, including COX-2, iNOS, Nrf2, SLC7A11, GPX4, and ACSL4. The Nrf2/SLC7A11/GPX4 axis and ACSL4 were suggested to be involved in ASMP-induced ferroptosis, leading to increased reactive oxygen species (ROS) levels and lipid peroxidation. These findings propose a unique mechanism by which ASMP exerts immunomodulatory effects through ferroptosis induction, contributing to the understanding of marine-derived compounds in immunomodulation research.

Extraction and characterization of polysaccharides from Schisandra sphenanthera fruit by Lactobacillus plantarum CICC 23121-assisted fermentation

Improving the yield of polysaccharides extracted from Schisandra sphenanthera is a major challenge in traditional Chinese medicinal plants. In this study, we investigated the potential of Lactobacillus plantarum CICC 23121-assisted fermentation as an extraction tool for S. sphenanthera polysaccharides (SSP). We observed that 11.12 ± 0.28 % of polysaccharides were extracted from S. sphenanthera using strain CICC 23121 -assisted fermentation (F-SSP), which was 53.38 % higher than that using hot water extraction (NF-SSP). The optimized parameters were a fermentation time of 15.5 h, substrate concentration of 4 %, and inoculum size of 3 %. Lactic acid produced by strain CICC 23121 increased the release of intracellular polysaccharides by breaking down cell walls. Compared to NF-SSP, F-SSP contained higher and lower total carbohydrate and protein contents, respectively, and its monosaccharide composition was the same as that of NF-SSP; however, their distributions were different. F-SSP had a higher molecular weight, better aqueous stability, and looser surface morphology, and strain CICC 23121-assisted fermentation did not change the molecular structure of SSP. Both NF-SSP and F-SSP showed the potential to regulate human intestinal microflora. Our findings revealed that strain CICC 23121-assisted fermentation is an efficient method for extracting S. sphenanthera polysaccharides without affecting their physicochemical and bioactive properties.

Structural characterization, anti-tumor and immunomodulatory activity of intracellular polysaccharide from Armillaria luteo-virens

Armillaria luteo-virens (A. luteo-virens) is a kind of edible fungus mainly exists in Qinghai-Tibet of China, but at present only very few studies focus on the bioactivities of its polysaccharides. This study aimed to purify and characterize the structure features of a novel intracellular polysaccharide (ALP-A) derived from A. luteo-virens and explore its potential anti-tumor and immunomodulatory activities. Through systematic separation and purification, we obtained a homogeneous ALP-A with an average molecular weight of 23693Da. Structural analysis indicated that ALP-A was mainly composed of glucose and mannose with a molar ratio of 6.02:1. The repeating unit of ALP-A was →4) -α-D-Glcp-(1→ backbone with α-Glcp-(1→ and α-Manp-(6→ side chains which branched at O-2 position. The anti-tumor assays in vivo suggested that ALP-A could effectively restrain S180 solid tumor growth, protect immune organs and promote the secretion of cytokines (IL2, IL6 and TNF-α) in serum. Besides, in vitro immunomodulatory assays indicated that ALP-A could improve proliferation, phagocytic capacity and raise the level of NO and cytokines in Raw264.7 cells. These results demonstrate that ALP-A which possess potential antitumor and immunomodulatory abilities can be developed as a new functional food.

Optimization of Se- and Zn-Enriched Mycelium of Lentinula edodes (Berk.) Pegler as a Dietary Supplement with Immunostimulatory Activity

Mycelial cultures of Lentinula edodes, an edible and medicinal mushroom, have been used in our previous research to obtain selenium-containing immunomodulatory preparations. Our current attempts to obtain a new preparation containing both selenium and zinc, two micronutrients necessary for the functioning of the immune system, extended our interest in the simultaneous accumulation of these elements by mycelia growing in media enriched with selenite and zinc(II) ions. Subsequently, we have studied the effects of new L. edodes mycelium water extracts with different concentrations of selenium and zinc on the activation of T cell fraction in human peripheral blood mononuclear cells (PBMCs). Flow cytometry analysis was used to measure the expression of activation markers on human CD4+ and CD8+ T cells stimulated by anti-CD3 and anti-CD3/CD28 antibodies (Abs). It was demonstrated that statistically significant changes were observed for PD-1 and CD25 antigens on CD8+ T cells. The selenium and zinc content in the examined preparations modified the immunomodulatory activity of mycelial polysaccharides; however, the mechanisms of action of various active ingredients in the mycelial extracts seem to be different.

Structural characterization of polysaccharide fractions in areca (Areca catechu L.) inflorescence and study of its immunological enhancement activity in vitro and in vivo

To obtain the structure-function relationship of the polysaccharides derived from areca (Areca catechu L.) inflorescences in the aspect of its immunomodulatory ability, the plant-based polysaccharide was isolated and purified on column chromatography. The purity, primary structure and immune activity of four polysaccharide fractions (AFP, AFP1, AFP2 and AFP2a) were characterized comprehensively. The main chain of AFP2a was confirmed to be composed of → 3,6)-β-D-Galp-(1→, with branch chains linked to the O-3 position on the main chain. The immunomodulatory activity of the polysaccharides was evaluated using the RAW264.7 cells and immunosuppression mice model. It was observed that AFP2a enabled greater NO release (49.72 μmol/L) than other fractions, significantly promoted the phagocytic activity of macrophages, and improved splenocyte proliferation and T lymphocyte phenotype in mice. The present results may shine a light on a new research direction in immunoenhancers and provide a theoretical foundation for the development and application of areca inflorescence.

Structural characterization and antinociceptive activity of polysaccharides from Anoectochilus elatus

Anoectochilus elatus is a new record species from Yunnan province in China discovered by our group in 2018, used in folk as the most popular Anoectochilus species A. roxburghii for medicinal and culinary purposes. The crude polysaccharide of Anoectochilus elatus (AEP) exhibited significant antinociceptive effects against both chemical and thermal nociception in vivo. Bio-guided isolation identified GJXL-1 as the leading analgesic polysaccharide in AEP. Detailed structural analyses rationalized GJXL-1 (molecular weight: 10.3 kDa) as an α-D-1,4-linked glucan unexpectedly branched at O-3, and O-6 position. GJXL-1 dose-dependently suppressed acetic acid-induced writhing in mice and decreased the serum levels of NO, IL-6 and TNF-α, which also repressed the licking times in both the first and second phases in formalin test. Furthermore, only L-nitroarginine partly reversed the analgesic activity of GJXL-1, indicating that GJXL-1's efficacy was partially mediated by NO regulation, possibly through inhibiting IRAK4/TAK1/NF-κB signaling pathway, and modulating gut microbiota and short-chain fatty acids production. In addition, the motor impairment and hypnotic effects of GJXL-1 were excluded. Our study suggests that GJXL-1 can be regarded as a promising and safe drug candidate for diverse pain disorders, and also a promising prebiotic candidate to maintain intestinal homeostasis and promote human gut health.

Microanalysis Characterization and Immunomodulatory Effect for Selenium-Enriched Polysaccharide from Morchella esculenta (L.) Pers

Morchella esculenta (L.) Pers., referred to as Morel, is a medicinal and edible homologous fungus, which contains many bioactive substances. In Morel, polysaccharides are the most abundant and have various bioactivities. In the present work, two novel polysaccharides, Se-MPS and MPS, were prepared and purified from selenium-enriched (Se-enriched) and common Morel mycelia, respectively, and their structural and immunomodulatory properties were evaluated. The results show that Se-enriched treatment significantly changed the polysaccharides' chemical composition, molecular weight, and sugar chain configuration. In addition, the Se-enriched treatment also improved the polysaccharides' fragmentation and thermal stability. Importantly, Se-enriched Morel polysaccharide (Se-MPS) could significantly enhance phagocytosis of RAW 264.7 macrophage cells and, remarkably, activate their immune response via activating the TLR4-TRAF6-MAPKs-NF-κB cascade signaling pathway, finally exerting an immunomodulatory function. Based on these findings, selenium-enriched Morel polysaccharide appears to have more potential for development and utilization in functional foods or medicines than ordinary Morel polysaccharide.

The Chemical Structure Properties and Promoting Biofilm Activity of Exopolysaccharide Produced by Shigella flexneri

Shigella flexneri is a waterborne and foodborne pathogen that can damage human health. The exopolysaccharides (S-EPS) produced by S. flexneri CMCC51574 were found to promote biofilm formation and virulence. In this research, the crude S-EPS produced by S. flexneri CMCC51574 were separated into three main different fractions, S-EPS 1-1, S-EPS 2-1, and S-EPS 3-1. The structure of the S-ESP 2-1 was identified by FT-IR, ion chromatography analysis, methylation analysis, and NMR analysis. The main chain of S-EPS 2-1 was α-Manp-(1 → 3)-α-Manp-[(1 → 2,6)-α-Manp]₁₅-[(1 → 2)-Manf-(1→]₈; there were two branched-chain R1 and R2 with a ratio of 4:1, R1: α-Manp-(1 → 6)- and R2: α-Manp-(1 → 6)- Glc-(1 → 6)- were linked with (1 → 2,6)-α-Manp. It was found that S-EPS 2-1 exhibited the highest promoting effect on biofilm formation of S. flexneri. The S-EPS 2-1 was identified to interact with extracellular DNA (eDNA) of S. flexneri, indicating that the S-EPS 2-1 was the specific polysaccharide in the spatial structure of biofilm formation. Our research found the important role of S-EPS in S. flexneri biofilm formation, which will help us to understand the underlining mechanisms of the biofilm formation and find effective ways to prevent S. flexneri biofilm infection.

Structural characterization and hepatoprotective effects of polysaccharides from Anoectochilus zhejiangensis

Two new polysaccharides, AZP-1a and AZP-1d, with molecular weights of 3.41 × 10⁴ and 4568 Da, respectively, were extracted from Anoectochilus zhejiangensis and purified by column chromatography. Their structural characteristics were systematically explored and results indicated AZP-1a and AZP-1d shared a similar backbone consisted of→4)-Galp-(1→, →4)-Glcp-(1→, and →4,6)-Glcp-(1→, with a different terminal residue of Manp-(1 → and Glcp-(1→, respectively. In vivo experiments showed that the crude polysaccharide of A. zhejiangensis (AZP) exhibited significant hepatoprotective effects, decreasing the serum levels of ALT, AST and LDH in CCl₄-treated mice, reducing MDA content, promoting SOD and CAT activities, and increasing GSH level in liver. Further in vitro investigation exhibited that AZP, AZP-1a and AZP-1d effectively protected liver cells against CCl₄-stimulated oxidative damage, while AZP-1a and AZP-1d functioned mainly through the activation of Nrf2 signaling pathway. Our results suggest that A. zhejiangensis polysaccharides can be applied as a potential resource for the development of hepatoprotective drugs.

Selenium-Containing Exopolysaccharides Isolated from the Culture Medium of Lentinula edodes: Structure and Biological Activity

In continuation of our research on the influence of selenium incorporation on the biosynthesis, structure, and immunomodulatory and antioxidant activities of polysaccharides of fungal origin, we have isolated from a post-culture medium of Lentinula edodes a selenium (Se)-containing exopolysaccharide fraction composed mainly of a highly branched 1-6-α-mannoprotein of molecular weight 4.5 × 10⁶ Da, with 15% protein component. The structure of this fraction resembled mannoproteins isolated from yeast and other mushroom cultures, but it was characterized by a significantly higher molecular weight. X-ray absorption fine structure spectral analysis in the near edge region (XANES) suggested that selenium in the Se-exopolysaccharide structure was present mainly at the IV oxidation state. The simulation analysis in the EXAFS region suggested the presence of two oxygen atoms in the region surrounding the selenium. On the grounds of our previous studies, we hypothesized that selenium-enriched exopolysaccharides would possess higher biological activity than the non-Se-enriched reference fraction. To perform structure-activity studies, we conducted the same tests of biological activity as for previously obtained mycelial Se-polyglucans. The Se-enriched exopolysaccharide fraction significantly enhanced cell viability when incubated with normal (human umbilical vein endothelial cells (HUVEC)) cells (but this effect was absent for malignant human cervical HeLa cells) and this fraction also protected the cells from oxidative stress conditions. The results of tests on the proliferation of human peripheral blood mononuclear cells suggested a selective immunosuppressive activity, like previously tested Se-polyglucans isolated from L. edodes mycelium. The Se-exopolysaccharide fraction, in concentrations of 10-100 µg/mL, inhibited human T lymphocyte proliferation induced by mitogens, without significant effects on B lymphocytes. As with previously obtained Se-polyglucans, in the currently tested Se-polymannans, the selenium content increased the biological activity. However, the activity of selenium exopolysaccharides in all tests was significantly lower than that of previously tested mycelial isolates, most likely due to a different mode of selenium binding and its higher degree of oxidation.

Selective Biological Effects of Selenium-Enriched Polysaccharide (Se-Le-30) Isolated from Lentinula edodes Mycelium on Human Immune Cells

A common edible mushroom Lentinula edodes, is an important source of numerous biologically active substances, including polysaccharides, with immunomodulatory and antitumor properties. In the present work, the biological activity of the crude, homogenous (Se)-enriched fraction (named Se-Le-30), which has been isolated from L. edodes mycelium by a modified Chihara method towards human peripheral blood mononuclear cells (PBMCs) and peripheral granulocytes, was investigated. The Se-Le-30 fraction, an analog of lentinan, significantly inhibited the proliferation of human PBMCs stimulated with anti-CD3 antibodies or allostimulated, and down-regulated the production of tumor necrosis factor (TNF)-α by CD3+ T cells. Moreover, it was found that Se-Le-30 significantly reduced the cytotoxic activity of human natural killer (NK) cells. The results suggested the selective immunosuppressive activity of this fraction, which is non-typical for mushroom derived polysaccharides.

Structure and pro-inflammatory activities of bran polysaccharides from a novel wheat kernel

In this study, the structure and pro-inflammatory activities of water-soluble wheat bran polysaccharides (WBP) were evaluated. WBP were heteropolysaccharides consisting 60.34% arabinoxylan as the main component and 31.80% mannose residues characterized with the instrumental analyses. The result of cellular experiment displayed that WBP had significant pro-inflammatory activities by increasing the concentration of nitric oxide (NO) and up-regulating the inflammatory cytokine expressions of inducible nitric oxide synthase (iNOS), interleukin-1β (IL-1β), cyclooxygenase-2 (COX-2), and tumor necrosis factor-α (TNF-α). WBP mediated macrophages RAW 264.7 pro-inflammatory response through phosphatidylinositol 3 hydroxykinase/protein kinase B (PI3K/Akt) signaling pathway by significantly promoting Akt and phosphoinositide-dependent kinase 1 (PDK1) phosphorylations. Meanwhile, the expression of related phosphorylated proteins JNK and ERK1/2 was significantly up-regulated which suggested that WBP played pro-inflammatory roles by activating mitogen-activated protein kinases (MAPKs) signaling pathway. PRACTICAL APPLICATIONS: In recent years, wheat bran generally has the phenomenon of high yield and low utilization rate. Wheat bran has rich nutritional value and contains a lot of effective biologically active substances. Based on our findings, the water-soluble polysaccharides extracted from wheat bran have significant effects on regulating immunity and can be utilized as sources of natural immune modulators. The research can develop new functions of wheat bran polysaccharides, and improve processing utilization rate and product added value.

Purification and comparative study of bioactivities of a natural selenized polysaccharide from Ganoderma Lucidum mycelia

The development of selenized polysaccharides is a promising strategy for the dietary selenium supplementation. The purpose of this research is to determine the influence of selenium on the structure and bioactivity of a polysaccharide fraction (MPN) isolated from Ganoderma lucidum mycelia. After biological selenium enrichment, the selenium content in the selenized polysaccharide (SeMPN) was 18.91 ± 1.8 μg/g. SeMPN had a slightly lower molecular weight than MPN, but the carbohydrate content and monosaccharide composition remained identical. Additionally, the band at 606 cm^-1 in MPN changed to 615 cm^-1 in SeMPN as revealed by FT-IR spectra. No significant changes were observed in the types and ratios of glycosidic linkages, as determined by NMR spectroscopy. Extracellular and intracellular antioxidant assays demonstrated that SeMPN was more effective than MPN in scavenging free radicals, inhibiting AAPH-induced erythrocyte hemolysis, and protecting catalase (CAT) and glutathione peroxidase (GSH-Px) activity in H₂O₂-injured PC12 cells. Additionally, SeMPN had a higher increase effect on RAW 264.7 cells's pinocytic and phagocytic capacity, as well as their production of NO, TNF-α, and IL-6. SeMPN could be as potential functional selenium supplementation.

Structure characteristics and immunomodulatory activities of a polysaccharide RGRP-1b from radix ginseng Rubra

The present study was undertaken to explore the structure characteristics, immune regulation, and anti-cancer abilities of polysaccharides in radix ginseng Rubra (RGR). For this purpose, RGR polysaccharides (RGRP) were purified through DEAE and S-300 chromatography. Monosaccharide composition, methylation, and GC-MS analyses, as well as field emission scanning electron microscope (FESEM), atomic force microscope (AFM), Fourier-transformed infrared resonance (FT-IR), and nuclear magnetic resonance (NMR) spectra, were used to establish the structure of RGRP-1b. Our results revealed that RGRP-1a and RGRP-1b possess different molecular weights (21.3 kDa and 10.2 kDa, respectively). RGRP-1a was found to be composed of glucose, while RGRP-1b was composed of glucose, galactose, and arabinose. The main chain structure of RGRP-1b was composed of 1,4-α-Glcp, with a 1,4,6-α-Glcp branch unit. Its side chains were branched at the O-4 position of 1,4,6-α-Glcp, namely 1)-β-Galp-(4 → 1)-α-Araf-(5 → α-Araf and 1)-β-Galp-(6 → α-Glcp. The changes in the nitric oxide (NO) levels and cytotoxicity revealed that macrophages probably get activated by RGRP-1b. The expressions of IL-6, IL-12, and TNF-α were found to be upregulated after treatment with RGRP-1b. RGRP-1b thus possesses the potential to arrest the growth of Huh7 through immunoregulation. Our cumulative findings indicate that RGRP-1b obtained from radix ginseng Rubra can function as a strong immune modulator.

Identification of the Primary Structure of Selenium-Containing Polysaccharides Selectively Inhibiting T-Cell Proliferation

We previously described the biosynthesis, isolation, and immunosuppressive activity of the selenium-containing polysaccharide fraction isolated from the mycelial culture of Lentinula edodes. Structural studies have shown that the fraction was a protein-containing mixture of high molar mass polysaccharides α- and β-glucans. However, which of the components of the complex fraction is responsible for the immunosuppressive activity non-typical for polysaccharides of fungal origin has not been explained. In the current study, we defined four-polysaccharide components of the Se-containing polysaccharide fraction determined their primary structure and examined the effect on T- and B-cell proliferation. The isolated Se-polysaccharides, α-1,4-glucan (M_w 2.25 × 10⁶ g/mol), unbranched β-1,6-d-glucan, unbranched β-1,3-d-glucan and β-1,3-branched β-1,6-d-glucan (M_w 1.10 × 10⁵ g/mol), are not typical as components of the cell wall of L. edodes. All are biologically active, but the inhibitory effect of the isolated polysaccharides on lymphocyte proliferation was weaker, though more selective than that of the crude fraction.

Structure characterization, antioxidant and emulsifying capacities of exopolysaccharide derived from Pantoea alhagi NX-11

Pantoea alhagi exopolysaccharides (PAPS) have been shown to enhance crop resistance to abiotic stress. However, physicochemical properties and structure of PAPS have not yet been analyzed. In this study, two PAPSs, named PAPS1 and PAPS2, were isolated and purified from the P. alhagi NX-11. The results showed PAPS1 and PAPS2 were composed of glucose, galactose, glucuronic acid, glucosamine and mannose with average molecular weight of 1.326 × 10⁶ Da and 1.959 × 10⁶ Da, respectively. Moreover, the structure of PAPS1 and PAPS2 was investigated by FT-IR and NMR analysis. PAPS1 was identified to have the backbone structure of →4)-β-D-GlcpA-(1→2)-α-D-Galp-(1→3)-β-D-Galp-(1→3)-β-D-GlcpN- (1→3)-α-D-Galp-(1→3)-β-D-Galp-(1→. PAPS2 had the backbone structure of →4)-β-D-GlcpA-(1→2)-α-D-Galp-(1→3)-β-D-Glcp-(1→3)-β-D-GlcpN-(1→3)-α-D-Galp-(1→3)-α-D-GlcpN-(1→. In addition, PAPS1 and PAPS2 had moderate antioxidant and emulsifying capacities. Overall, the structure analysis of PAPS may point out the direction for the subsequent study of PAPS-mediated microbial and plant interactions, and further exploration of the application of PAPS.

Selenium-Containing Polysaccharides—Structural Diversity, Biosynthesis, Chemical Modifications and Biological Activity

Selenosugars are a group of sugar derivatives of great structural diversity (e.g., molar masses, selenium oxidation state, and selenium binding), obtained as a result of biosynthesis, chemical modification of natural compounds, or chemical synthesis. Seleno-monosaccharides and disaccharides are known to be non-toxic products of the natural metabolism of selenium compounds in mammals. In the case of the selenium-containing polysaccharides of natural origin, their formation is also postulated as a form of detoxification of excess selenium in microorganisms, mushroom, and plants. The valency of selenium in selenium-containing polysaccharides can be: 0 (encapsulated nano-selenium), IV (selenites of polysaccharides), or II (selenoglycosides or selenium built into the sugar ring to replace oxygen). The great interest in Se-polysaccharides results from the expected synergy between selenium and polysaccharides. Several plant- and mushroom-derived polysaccharides are potent macromolecules with antitumor, immunomodulatory, antioxidant, and other biological properties. Selenium, a trace element of fundamental importance to human health, has been shown to possess several analogous functions. The mechanism by which selenium exerts anticancer and immunomodulatory activity differs from that of polysaccharide fractions, but a similar pharmacological effect suggests a possible synergy of these two agents. Various functions of Se-polysaccharides have been explored, including antitumor, immune-enhancement, antioxidant, antidiabetic, anti-inflammatory, hepatoprotective, and neuroprotective activities. Due to being non-toxic or much less toxic than inorganic selenium compounds, Se-polysaccharides are potential dietary supplements that could be used, e.g., in chemoprevention.

The characterization of optimal selenized garlic polysaccharides and its immune and antioxidant activity in chickens

The purpose of this study was to optimize modification conditions of selenized garlic polysaccharides (sGPS) and investigate its structural characterization, immune and antioxidant activities. Herein, selenized garlic polysaccharides (sGPS) were prepared using by HNO₃-Na₂SeO₃ selenylation method. And then modification conditions of sGPS were optimized through L₉ (3⁴) orthogonal test. The structural characterization of sGPS were identified by the Fourier-transform infrared (FT-IR), Solid-State nuclear magnetic resonance (NMR) spectra, X-ray diffraction (XRD) and thermogravimetric (TGA). The morphology of sGPS was detected using scanning electron microscope (SEM) and transmission electron microscope (TEM). In vivo investigation showed that sGPS significantly improved serum hemagglutination-inhibition (HI) antibody titers against Newcastle disease virus, enhanced secretory IgA (sIgA), IFN-γ, IL-2 secretion in jejunum and trachea irrigation compared with vaccine immunized control group. Furthermore, it showed that sGPS had some effects on the antioxidant activities in livers of chickens. In conclusion, the optimal modification conditions of sGPS were as follows: reaction temperature was 70 °C, the dosage of Na₂SeO₃ was 400 mg and reaction time was 6 h. The selenylation modification of garlic polysaccharides (GPS) could improve its immune and antioxidant activity in chickens.

Characterization and anti-diabetic nephropathic ability of mycelium polysaccharides from Coprinus comatus

It seems quite necessary for obtaining effective substances from natural products against the diabetic nephropathic (DN) with the presently clinical problems of accompanying side-effects and lowing life qualities. This work aimed to characterize the primary structure of Coprinus comatus mycelium polysaccharides (CMP) and investigate the abilities against DN in streptozotocin induced mice models. The results indicated that CMP could improve insulin resistance and energy metabolism, and significantly suppress dysfunction on kidney and relieve the renal oxidative stress and inflammation in DN mice. Besides, the western blot results suggested that CMP reversed renal injury by modulating the PTEN/PI3K/Akt and Wnt-1/β-catenin pathways. The structure analysis indicated the typical characterizations with the major monosaccharide-compositions of galactose, α-pyranose configuration and proper molecular weights of 495.8 kDa possibly contributed to the anti-diabetic nephropathic effects of CMP. The results suggested that polysaccharides form C. comatus could be used as functional foods/drugs on preventing diabetic nephropathy.

Regulatory protein genes and microRNAs in response to selenium stimuli in Pueraria lobata (Willd.) Ohwi

Regulatory protein genes and microRNAs (miRNAs) play important roles in response to abiotic and biotic stress, and the biosynthesis of secondary metabolites in plants. However, their responses to selenium (Se) stimuli have not been comprehensively studied in Pueraria lobata (Willd.) Ohwi, a selenocompound-rich medicinal and edible plant. In this study, we identified a total of 436/556/1161/624 transcription factors, 134/157/308/172 transcriptional regulators, and 341/456/250/518 protein kinases, which were co-expressed with at least one selenocompound-related structural gene/sulfate transporter or phosphate transporter/reactive oxygen species (ROS) scavenging structural gene/isoflavone-related structural gene, respectively. Then, we identified a total of 87 expressed miRNAs by Se disposure, in which 11 miRNAs, including miR171f-3p, miR390b-3P, miR-N111b, miR-N118, miR-N30, miR-N38-3P, miR-N61a, miR-N61b, miR-N80-3p, miR-N84-3P, and miR-N90.2-3P, were significantly upregulated. We also identified a total of 1172 target genes for the 87 expressed miRNAs. Gene Ontology enrichment analysis of these target genes showed that regulation of transcription, DNA-templated, integral component of membrane, nucleus, ATP binding, and plasma membrane are the top five subclassifications. Finally, we revealed that 5 miRNAs targeted 10 regulatory protein genes, which are highly correlated with at least one selenocompound-related structural gene or transporter gene; 5 miRNAs targeted 10 regulatory protein genes, which are highly correlated with at least one ROS scavenging structural gene; and 5 miRNAs targeted 9 regulatory protein genes, which are potentially involved in the isoflavone biosynthesis. Overall, the study provides us the comprehensive insight into the roles of regulatory proteins and miRNAs in response to Se stimuli in P. lobata.

Characterization of selenium-containing polysaccharide from Spirulina platensis and its protective role against Cd-induced toxicity

Herein, selenium-containing polysaccharide from Spirulina platensis (Se-SPP) was prepared and its structural characteristics and protective role against Cd-induced toxicity in vivo and in vitro were investigated. Se-SPP was alkali-extracted from selenium-containing Spirulina platensis which was cultured in Zarrouk medium supplemented with Na₂SeO₃. The contents of carbohydrate, protein, uronic acid, sulfate and elements (including Se, C, H, O, N, and S) as well as the monosaccharide composition, molecular weight, surface morphology and FT-IR spectra of Se-SPP was compared to that of selenium-free polysaccharide (SPP). The results revealed that SPP and Se-SPP were both high-molecular-weight heteropolysaccharide with similar molecular weight and monosaccharide composition but significantly different selenium content, indicating that the covalently-bonding of a small amount of selenium did not destroy the original structure of polysaccharide. Furthermore, CdCl₂ was utilized to build Cd-intoxicated cells model in vitro and rats model in vivo respectively. Then, the protective effect of Se-SPP against cadmium-induced toxicity was assessed. The results demonstrated that Se-SPP treatment provided significant protection against Cd-induced toxicity, which was superior compared to that of SPP or Na₂SeO₃ alone. The enhancement of protective role may be affected by the covalently-bonding of selenium to polysaccharide.

Structural characterization and anticomplement activities of three acidic homogeneous polysaccharides from Artemisia annua

ETHNOPHARMACOLOGICAL RELEVANCE

Artemisia annua L. is a heat-clearing Chinese medicine and well-known for its antimalarial constituent, artemisinin. It has gained increasing attention for its anti-inflammatory and immunoregulatory activities. Interestingly, the crude polysaccahrides of A. annua exhibited potent anticomplement activity. This study was to isolate and characterize its anticomplement homogeneous polysaccharides from A. annua, and reveal the relationship between structures and anticomplement activities of the isolated polysaccharides.

MATERIALS AND METHODS

Water-soluble crude polysaccharides from the aerial parts of A. annua were extracted and fractionated by DEAE-cellulose and Sephacryl S-300 gel permeation chromatography. Homogeneity, molecular weight, monosaccharide composition, methylation and NMR analysis were performed to characterize the structures of homogeneous polysaccharides. Their anticomplement activities and targeting components in the complement activation cascade were evaluated by hemolytic assays.

RESULTS

Three homogeneous polysaccharides (AAP01-1, AAP01-2 and AAP01-3) were obtained from A. annua. AAP01-1 was composed of seven monosaccharides, including mannose, rhamnose, glucuronic acid, galacturonic acid, glucose, galactose and arabinose. AAP01-2 and AAP01-3 had similar monosaccharides with AAP01-1, except the absence of glucuronic acid. They were all branched acidic heteropolysaccharides with different contents of galacturonic acid (8%, 28% and 15% for AAP01-1, AAP01-2 and AAP01-3, respectively). AAP01-2 showed potent anticomplement activity with CH₅₀ value of 0.360 ± 0.020 mg/mL through the classical pathway and AP₅₀ value of 0.547 ± 0.033 mg/mL through the alternative pathway. AAP01-3 exhibited slightly weaker activity (CH₅₀: 1.120 ± 0.052 mg/mL, AP₅₀: 1.283 ± 0.061 mg/mL), while AAP01-1 was inactive. Moreover, AAP01-2 acted on C1q, C3, C4, C5 and C9 components and AAP01-3 interacted with C3, C4 and C5 components in the activation cascade of complement system.

CONCLUSION

These results indicated that the relatively high contents of galacturonic acid were important for anticomplement activities of the polysaccharides from A. annua. The anticomplement polysaccharides are another kind of bioactive constituents conferring heat-clearing effects of A. annua.

Research progress on the biological activities of selenium polysaccharides

Selenium polysaccharides, an important organic selenium product, possess better antioxidant, antitumour, immune regulation, hypoglycaemic, and heavy metal removal activities than that of either polysaccharides or inorganic selenium.

Preparation, characterization, antioxidant and antiglycation activities of selenized polysaccharides from blackcurrant

An ultrasound-assisted enzymatic method was used to extract the polysaccharides from blackcurrant fruits (BP), and then a nitric acid-sodium selenite method was employed to prepare twelve kinds of selenized blackcurrant polysaccharides (SBPs). Among them, SBP-1, SBP-2 and SBP-3 with different selenium contents of 250 ± 11, 312 ± 15 and 643 ± 24 μg g⁻¹, displayed relatively higher 2,2-diphenyl-1-picrylhydrazyl radical (DPPH˙) scavenging activities than the others. After treating with a Sepharose-6B chromatography column, the purified blackcurrant polysaccharide (PBP) and three selenized polysaccharides (PSBP-1, PSBP-2, PSBP-3) with high purity were obtained. Compared with PBP, PSBPs possessed a larger absolute value of zeta potential (ZP) and smaller particle size, indicating the positive influence of selenized modification on physical stability of polysaccharides. Ultraviolet (UV), Fourier transform infrared (FT-IR) and circular dichroism (CD) spectra confirmed that selenium had been introduced onto the polysaccharide structure. X-ray diffraction (XRD) and I₂–KI reaction results indicated that selenized modification did not cause an obvious change in crystal form and branch structure of blackcurrant polysaccharides. In addition, PSBPs were superior to PBP in antioxidant and antiglycation capacities, and the bioactivities of PSBPs were significantly improved in positive correlation with selenium content. This study suggested that PSBPs may be a potential selenium source and serve as functional food and medicine.

An ultrasound-assisted enzymatic method was used to extract the polysaccharides from blackcurrant fruits (BP), and then a nitric acid-sodium selenite method was employed to prepare twelve kinds of selenized blackcurrant polysaccharides (SBPs).

Simultaneous Use of Stimulatory Agents to Enhance the Production and Hypoglycaemic Activity of Polysaccharides from Inonotus obliquus by Submerged Fermentation

This study aimed to determine the effect of applying stimulatory agents to liquid cultured Inonotus obliquus on the simultaneous accumulation of exo-polysaccharides (EPS) and their monosaccharide composition. Different stimulatory agents (VB₆, VB₁, betulin and birch extract) were investigated for their effects on active exo-polysaccharides by submerged fermentation of I. obliquus. The mycelial biomass, reducing sugar content, EPS yield and α-glucosidase inhibition rate were determined, and the EPS obtained was analyzed for monosaccharide composition. The results showed that the addition of all the four stimulatory agents could significantly increase the inhibitory activity against α-glucosidase of EPS than the control, whereas EPS from 4 μg/mL VB₁-containing medium had the best effect with an estimated IC₅₀ value 24.34 μg/mL. Among the four stimulatory agents, VB₆ gave maximum production of mycelial biomass and EPS at the concentration of 4 μg/mL with a increase of 50.79% and 114.46%, respectively. In addition, betulin had a significant effect on increasing the EPS yield and activity, and birch extract had a significantly stimulatory effect on the mycelial growth and the polysaccharides activity, only slightly worse than VB₆ and VB₁. Moreover, the addition of different stimulatory agents changed the monosaccharide composition of polysaccharides, which had a correlation with polysaccharide activity.

Structural characterization and anticomplement activity of an acidic polysaccharide from Hedyotis diffusa

An acidic homogeneous polysaccharide (HD-PS-1) was purified from Hedyotis diffusa (Willd.) Roxb. HD-PS-1 possessed a backbone chain of →[4)-β-Glcp-3-OAc-(1]₆→[6)-β-Manp-(1]₂→6)-α-Galp-(1→[4)-α-Galp-(1]₂→, with three branches of β-Manp-(1→3)-β-GlcpA, α-Rhap-(1→3)-α-Rhap and α-Galp attached to the backbone chain at O-4 position of 1,4,6-linked β-Manp, O-3 position of 1,3,6-linked α-Galp and O-3 position of 1,3,4-linked α-Galp, respectively. HD-PS-1 exhibited significant anticomplement activity (CH₅₀: 0.084 ± 0.009 mg/mL, AP₅₀: 0.176 ± 0.013 mg/mL). It was found that the presence of uronic acids is important to anticomplement activity of HD-PS-1, given that the reduced HD-PS-1 showed weaker activity (CH₅₀: 0.456 ± 0.008 mg/mL, AP₅₀: 0.572 ± 0.010 mg/mL). Preliminary mechanism study indicated that HD-PS-1 interacted with C3 and C4 in the complement activation cascade. In addition, a neutral homogeneous polysaccharide (HD-PS-2) was also purified and characterized. HD-PS-2 displayed antioxidant activity by scavenging DPPH· radicals without anticomplement activity.

Polysaccharides of mushroom Pleurotus spp.: New extraction techniques, biological activities and development of new technologies

The biodiversity of mushrooms Pleurotus spp. is impressive due to its complexity and diversity related to the composition of chemical structures such as polysaccharides, glycoproteins and secondary metabolites such as alkaloids, flavonoids and betalains. Recent studies of polysaccharides and their structural elucidation have helped to direct research and development of technologies related to pharmacological action, production of bioactive foods and application of new, more sophisticated extraction tools. The diversity of bioactivities related to these biopolymers, their mechanisms and routes of action are constant focus of researches. The elucidation of bioactivities has helped to formulate new vaccines and targeted drugs. In this context, in terms of polysaccharides and the diversity of mushrooms Pleurotus spp., this review seeks to revisit the genus, making an updated approach on the recent discoveries of polysaccharides, new extraction techniques and bioactivities, emphasising on their mechanisms and routes in order to update the reader on the recent technologies related to these polymers.

Variations in Nuclear Number and Size in Vegetative Hyphae of the Edible Mushroom Lentinula edodes

In basidiomycete fungi, the number of nuclei and their ploidy level per nucleus can vary tremendously among species; however, within species, nuclear number and ploidy levels are traditionally considered fixed in their vegetative hyphae. In the edible mushroom Lentinula edodes, the hyphae are classified as either monokaryotic or dikaryotic, with each monokaryotic hyphal cell containing one haploid nucleus, and each dikaryotic hyphal cell containing two haploid nuclei. The dikaryotic hyphae are the results of mating between two genetically distinct monokaryons with different mating types. In this study, we examined the nuclear number and size (a potential correlate to ploidy) of L. edodes mycelia throughout its vegetative growth. We found that the number of nuclei within individual hyphal cells varied widely from non-nucleated to uninucleated, dinucleated, and multinucleated. Additionally, different nuclei within the same cell appeared very different in size, with a maximum nucleus cross-sectional area of 4.94 μm2 and the minimum nucleus cross-sectional area at only 0.37 μm2. Moreover, as culture time increased, more cells appeared to be devoid of any nuclei, with transmission electron microscopy and terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assays of late-stage cultures showing autophagosomes fusing and dissolving the nuclei and resulting in a large number of TUNEL-positive DNA fragments in non-nucleated cells. These results indicated that non-nucleated cells were likely caused by autophagy and apoptosis-like activities within aging L. edodes hyphae.

An alcohol-soluble polysaccharide from Atractylodes macrocephala Koidz induces apoptosis of Eca-109 cells

In this study, polysaccharides from Atractylodes macrocephala Koidz (APA) which were soluble in alcohol were prepared, purified, analyzed the structure and investigated the antitumor activity in vitro cell experiment. Results of high-performance gel permeation chromatography (HPGPC), fourier-transform infrared spectroscopy (FT-IR), and gas chromatography (GC) showed that APA was a 2.1KDa neutral hetero polysaccharide composed of arabinose and glucose (molar ratio, 1.00:4.57) with pyranose rings and α-type and β-type glycosidic linkages. Results by MTT experiments showed that the proliferation inhibition was 74.63% in Eca109 cells treated with 2 mg/mL dose of APA. Annexin V/PI assay, Hoechst 33,258 staining, cell cycle distribution, rhodamine 123 dye assay and western blot assay clarified that APA could accelerate the apoptosis of Eca109 cells by mitochondrial pathway and stocked cells at S phase. These data indicated that APA is a promising potential candidate for therapeutic treatment of esophageal cancer.

Relationship between structural properties and antitumor activity of Astragalus polysaccharides extracted with different temperatures

This study investigated the effects of different temperatures on structural characterization and antitumor activity of polysaccharides from Astragalus membranaceus. APS4 and APS90 were extracted at 4°C and 90°C, respectively, and purified by Sephadex G-200 column. APS4-90 were obtained from APS4 after treatment at 90°C for 6h. MTT results showed that APS4 possessed the highest inhibitory effects on MGC-803, A549 and HepG2 cells. HPGPC analysis showed that the average molecular weights of these polysaccharides were approximately 1.5×10⁶Da, while the asymmetrical peak of APS4-90 suggested heat degradation and configuration changes of APS4. GC, NMR and methylation results showed that these three polysaccharides had similar monosaccharide components (mainly contain glucose), and their backbones were composed of (1→2)‑α‑d‑Glcp. However, APS4 showed higher content of (1→2,6)‑α‑d‑Glcp compared to APS4-90 and APS90, which indicated that higher branched degree would be responsible for the stronger in vitro antitumor activity in APS4. These results were also confirmed by specific rotation and SEM analysis. Our study suggested that APS4 had the potential application for cancer treatment.