Structural characterization and immunomodulatory activity of intracellular polysaccharide from the mycelium of Paecilomyces cicadae TJJ1213

The structural features and anti-inflammatory properties of a glucogalactan from Holotrichia diomphalia Bates (Qi Cao)

ETHNOPHARMACOLOGICAL RELEVANCE

The dried larvae of Holotrichia diomphalia Bates, named Qi Cao, is a traditional Chinese medicine treat for liver diseases and arthritis. Polysaccharides is a principal component in Qi Cao, which exhibiting antioxidant and anti-inflammatory effects. However, the structural characteristics and underlying mechanisms of the polysaccharides remain inadequately elucidated.

AIM OF THE STUDY

To analyze the primary structure and elucidate the molecular anti-inflammatory mechanisms of the active polysaccharide in Qi Cao.

MATERIALS AND METHODS

The total polysaccharide was extracted by water extraction and alcohol precipitation, and further isolated and purified by DEAE Sephadex A-25 column and Sephadex G-100 column. The anti-inflammatory properties of four major fractions (HDPS-1, HDPS-2, HDPS-3, HDPS-4) and the pure homogeneous polysaccharides (HDPS-1I and HDPS-1II) were assessed using a RAW 264.7 cell model induced by lipopolysaccharide (LPS), and HDPS-1II was identified as the polysaccharide exhibiting significant anti-inflammatory activity in Qi Cao. The structural characteristics of HDPS-1II were subsequently analyzed using high-performance size-exclusion chromatography (HPSEC), fourier-transform infrared spectroscopy (FT-IR), gas chromatography-mass spectrometry (GC-MS), and nuclear magnetic resonance (NMR) spectroscopy. The TLR4, NF-κB, COX-2 and iNOS expressions were determined by Western blot analysis to investigate the anti-inflammatory mechanism of HDPS-1II in vitro. Finally, the in vivo anti-inflammatory activity of HDPS-1II were evaluated by measuring the serum levels of pro-inflammatory factors, inflammatory cell infiltration and organelle damage in the lung tissues of sepsis model mice.

RESULTS

A homogeneous polysaccharide (HDPS-1II) with molecular weight of 1.7 × 104 Da was isolated from Holotrichia diomphalia Bates. HDPS-1II contains a backbone of α-T-Glcp-(1 → 6)-α-Glcp-(1 → 4)-α-Galp-(1 → 4)-α-Galp-(1 → 6)-α-Galp-(1 → 3)-α-Galp-(1 → . It inhibited activation of the TLR4/NF-κB signaling and reduced pro-inflammatory factors and NO in LPS-stimulated macrophage. Moreover, HDPS-1II increased the survival rate, inhibited inflammatory cells infiltration, and ameliorated the lung tissue damage in septic mice.

CONCLUSIONS

HDPS-1II exhibits anti-inflammatory effects in vitro and in vivo, which is the active polysaccharide components of the anti-inflammatory activity of Qi Cao.

Cordyceps Polysaccharides: A Review of Their Immunomodulatory Effects

Cordyceps primarily consists of ascomycetes, a parasitic fungus that infects insects and arthropods. Recently, Cordyceps has been shown to manifest a diverse range of pharmacological activities, rendering it applicable for the treatment and mitigation of various diseases, such as diabetes, acute liver injury, and colitis. Many active constituents have been identified from Cordyceps sinensis, including cordycepin, adenosine, sterols, and polysaccharides. Polysaccharides constitute a primary active component of Cordyceps, exhibiting immunomodulatory effects. We searched the Web of Science database with the keywords of cordyceps, polysaccharide, and immune modulation; collected related studies from 2004 to 2024; and eliminated articles with low influence and workload. A review of the research advancements regarding the immunomodulatory effects of Cordyceps polysaccharides was conducted with the aim of furnishing valuable reference information. Research indicates that polysaccharides exhibiting immunomodulatory activity are predominantly sourced from Cordyceps sinensis and Cordyceps militaris. Immunological experimental results demonstrate that Cordyceps polysaccharides can augment the activities of macrophages, lymphocytes, and dendritic cells while fostering the expression of immune-active substances such as cytokines and chemokines. Furthermore, animal experiments have substantiated the immunomodulatory effects of Cordyceps polysaccharides. These effects encompass ameliorating immune suppression induced by drugs or radiation, enhancing immune organ indices, elevating the expression of immunoreactive substances, and mitigating immune evasion prompted by tumors. In conclusion, Cordyceps polysaccharides exhibit significant immunomodulatory activity and merit further investigation.

Polysaccharide from Boletus aereus ameliorates DSS-induced colitis in mice by regulating the MANF/MUC2 signaling and gut microbiota

Inflammatory bowel diseases (IBD) are chronic inflammatory conditions characterized by disruptions in the colonic mucus barrier and gut microbiota. In this study, a novel soluble polysaccharide obtained from Boletus aereus (BAP) through water extraction was examined for its structure. The protective effects of BAP on colitis were investigated using a DSS-induced mice model. BAP was found to promote the expression of intestinal mucosal and tight junction proteins, restore the compromised mucus barrier, and suppress the activation of inflammatory signaling. Moreover, BAP reshape the gut microbiota and had a positive impact on the composition of the gut microbiota by reducing inflammation-related microbes. Additionally, BAP decreased cytokine levels through the MANF-BATF2 signaling pathway. Correlation analysis revealed that MANF was negatively correlated with the DAI and the level of cytokines. Furthermore, the depletion of gut microbiota using antibiotic partially inhabited the effect of BAP on the activation of MANF and Muc2, indicating the role of gut microbiota in its protective effect against colitis. In conclusion, BAP had an obvious activation on MANF under gut inflammation. This provides new insights into the prospective use of BAP as a functional food to enhance intestinal health.

Effect of Lactobacillus helveticus exopolysaccharides molecular weight on yogurt gel properties and its internal mechanism

The processing characteristics of yogurt are closely related to the composition and arrangement of exopolysaccharides (EPS) in lactic acid bacteria (LAB). To fully understand and develop the functional properties of EPS and to study the effect of EPS molecular weight on yogurt and its mechanism, the physicochemical properties of high molecular weight EPS-LH43, medium molecular weight EPS-LH13, and low molecular weight EPS-LH23, as well as the gel properties and protein conformation of yogurt, were determined and analyzed in this experiment. The results indicate that EPS-LH43 and EPS-LH13 are both composed of mannose, rhamnose, galacturonic acid, glucose, and galactose. EPS-LH23 is composed of mannose, galacturonic acid, glucose, and galactose. Their Number-average Molecular Weight is 5.21 × 106 Da, 2.39 × 106 Da and 3.76 × 105 Da, respectively. In addition, all three types of EPS have good thermal stability and can improve the stability of casein. In addition, the analysis of the texture, particle size, potential, water holding capacity, rheology, low field nuclear magnetic resonance, microstructure, and flavor characteristics of yogurt confirmed the relationship between the molecular weight of LAB EPS and the gel properties of yogurt. Fluorescence spectrophotometer and circular dichroism analysis indicate that the different molecular weights of LAB EPS have different effects on protein structure, which is an intrinsic factor leading to significant differences in the gel properties of the three types of fermented milk. These findings provide new references for enhancing the understanding of the structure-activity relationship of EPS and indicate that EPS-LH43 can be used to improve the gel properties of dairy products.

Effect of exopolysaccharides yield and addition concentration of Lactobacillus helveticus on the processing characteristics of fermented milk and its mechanism

Exopolysaccharides (EPS) yield and added concentration of lactic acid bacteria can greatly affect the processing characteristics of fermented milk. In order to investigate the effects and mechanisms of EPS yield and added concentration on fermented milk, researchers extracted EPS from 50 strains of Lactobacillus helvedicus (L. helvedicus) and selected the two strains with the largest difference in EPS yield (L. helvedicus LH18 and L. helvetigus LH33) for subsequent experiments. The physicochemical properties of EPS-LH18 and EPS-LH33 were analyzed. The gel characteristics and protein conformation of fermented milk were studied by means of texture analyzer, rheometer, scanning electron microscopy, nuclear magnetic resonance machine, fluorescence spectrophotometer and circular dichroism. The results indicate that the monosaccharide compositions of EPS-LH18 and EPS-LH33 are the same and have good thermal stability. The texture and rheological properties of L. helveticus LH18 fermented milk are significantly superior to other fermented milk. The reason is that L. helveticus LH18 EPS has the highest yield, which leads to a denser gel structure, lower surface hydrophobicity and free sulfhydryl content of its fermented milk. According to circular dichroism analysis, β- sheet and random coil are the internal factors leading to the difference in fermented milk gel. In addition, the fermented milk improved even more favorably as the concentration of the two EPS additions increased. As described above, L. helveticus LH18 has the potential to be an excellent yogurt starter, and both of the above EPS can be used as probiotic stabilizer alternatives for fermented dairy products.

Structural and functional characterization of exopolysaccharide from Leuconostoc citreum BH10 discovered in birch sap

In this study, Leuconostoc citreum BH10, an endophytic strain, was isolated from aseptically collected xylem sap of birch for the first time, and its exopolysaccharide (LCEPS) production was up to 46.31 g/L in glucan producing medium. The produced LCEPS was purified to obtain two water-soluble fractions, named as LCEPS-1 and LCEPS-2, respectively. The major fraction LCEPS-1 was characterized to be comprised of glucose with average molecular weight of 6.34 × 106 Da. The structure of LCEPS-1 was investigated by spectroscopy analysis, which revealed that LCEPS-1 was identified with containing 90.45 % α-(1,6) linkages in the main chains and 9.55 % α-(1,3) branch linkages. The scanning electron microscope results demonstrated that the dried LCEPS-1 appeared porous surface overlaid with an irregular glittering. The water solubility index (WSI) and water holding capacity (WHC) of LCEPS-1 were 88.02 ± 1.69 % and 241.43 ± 6.38 %, respectively. Besides, it exhibited high thermal stability as well as fine antioxidant activities. Taken together, the results indicated that LCEPS-1 could have good potentiality to be applied in fields of foods, cosmetics, nutraceuticals and pharmaceutical industries as the natural agent.

Immunomodulatory activity and protective effect of a capsular polysaccharide in Caenorhabditis elegans, isolated from Lactobacillus fermentum GBJ

A capsular polysaccharide, namely CPS-2, was isolated from Lactobacillus fermentum GBJ, purified using DEAE-52 anion exchange chromatography, and structurally characterized. We found that CPS-2 is homogenous, has an average molecular weight of 377 KDa, and is mainly composed of galactose and glucose at a molar ratio of 1.54:1.00. Its backbone comprises α-D-Galp-(1 → 3), α-D-Galp-(1 → 3,6), β-D-Glcp-(1 → 2), β-D-Galp-(1 → 6), and α-D-Galp-(1 → 4) residues with a side chain of β-D-Glcp-(1→). CPS-2 exerts an immunomodulatory effect by improving the proliferation and phagocytosis of macrophage RAW264.7 and promoting the secretion of NO and cytokines. The maximum secretion levels of IL-1β, IL-6, IL-10, and TNF-α were 1.96-, 0.11-, 0.22-, and 0.46-fold higher than those of the control, respectively. Furthermore, CPS-2 could significantly enhance the antioxidant system, extend lifespan, and improve stress tolerance of Caenorhabditis elegans at both exposure doses of 31.25 and 62.5 μg/mL. The average lifespan of nematodes reached a maximum in the 62.5 μg/mL-treated group after 10.39 days, 6.56 h, and 23.56 h in normal, oxidative stress, and heat shock environment, with extension percentages of 16.61 %, 43.23 %, and 15.77 %, respectively; therefore, CPS-2 displays an anti-aging effect. The significant bioactivity of CPS-2 promotes its application as a promising immunomodulatory and anti-aging ingredient in the food or pharmaceutical field.

Structural Characterization and Immunomodulatory Activity of a Mannose-Rich Polysaccharide Isolated from Bifidobacterium breve H4-2

In this study, a novel homogeneous mannose-rich polysaccharide named EPS-1 from the fermentation broth of Bifidobacterium breve H4-2 was isolated and purified by anion exchange column chromatography and gel column chromatography. The primary structure of EPS-1 was analyzed by high-performance liquid chromatography, Fourier-transform infrared spectroscopy, gas chromatography-mass spectrometry, and nuclear magnetic resonance. The results indicated that EPS-1 had typical functional groups of polysaccharides. EPS-1 with an average molecular weight of 3.99 × 104 Da was mainly composed of mannose (89.65%) and glucose (5.84%). The backbone of EPS-1 was →2,6)-α-d-Manp-(1→2)-α-d-Manp-(1→2,6)-α-d-Manp-(1→2)-α-d-Manp-(1→2,6)-α-d-Manp-(1→6)-α-d-Glcp-(1→ simultaneously containing two kinds of branched chains (α-d-Manp-(1→3)-α-d-Manp-(1→ and α-d-Manp-(1→). Besides, EPS-1 had a triple-helical conformation and exhibited excellent thermal stability. Moreover, the immunomodulatory activity of EPS-1 was evaluated by RAW 264.7 cells. Results indicated that EPS-1 significantly enhanced the viability of RAW 264.7 cells. EPS-1 could also be recognized by toll-like receptor 4, thereby activating the nuclear factors-κB (NF-κB) signaling pathway, promoting phosphorylation of related nuclear transcription factors, improving cell phagocytic activity, and promoting the secretion of NO, IL-6, IL-1β, and TNF-α. Thus, EPS-1 could activate the TLR4-NF-κB signaling pathway to emerge immunomodulatory activity on macrophages. The above results indicate that EPS-1 can serve as a potential immune-stimulating polysaccharide.

Isolation and structural characterization of exopolysaccharide from the Cordyceps cicadae and the immunomodulatory activity on RAW264.7 cells

A new exopolysaccharide component named as PC-EPS was isolated from Cordyceps cicadae, and its structure was determined. PC-EPS was identified to be constituted of mannose, glucose, and galactose (28.84:1:19.42), with an average molecular weight of 3.72 × 106  Da, according to the results of monosaccharide composition, Fourier transform infrared, nuclear magnetic resonance, periodate oxidation and Smith degradation, and methylation studies. According to structural characterization, PC-EPS's connection type was made up of →6) -α-d-Manp (1→, →2) -β-d-Manp (1→, →4) -α-d-Manp (1→, →2) -α-d-Galf (1→, and →4) -α-d-Galp (1→. PC-EPS may significantly increase phagocytosis and RAW264.7 cell proliferation. Additionally, by boosting intracellular lysozyme, cellular acid phosphatase, and cellular superoxide dismutase enzyme concentrations, as well as by promoting the generation of cellular NO, it is the potential to regulate the immunological activity of RAW264.7 cells. Additionally, the effects of PC-EPS on RAW264.7 cells increased their capacities to create tumor necrosis factor-α and interleukin 6 cytokines, all of which suggested that PC-EPS had the potential to improve immunomodulatory activity.

A Neutral Polysaccharide from Spores of Ophiocordyceps gracilis Regulates Oxidative Stress via NRF2/FNIP1 Pathway

Ophiocordyceps gracilis (O. gracilis) is a parasitic fungus used in traditional Chinese medicine and functional foods. In this study, a neutral heteropolysaccharide (GSP-1a) was isolated from spores of O. gracilis, and its structure and antioxidant capacities were investigated. GSP-1a was found to have a molecular weight of 72.8 kDa and primarily consisted of mannose (42.28%), galactose (35.7%), and glucose (22.02%). The backbone of GSP-1a was composed of various sugar residues, including →6)-α-D-Manp-(1→, →2,6)-α-D-Manp-(1→, →2,4,6)-α-D-Manp-(1→, →6)-α-D-Glcp-(1→, and →3,6)-α-D-Glcp-(1→, with some branches consisting of →6)-α-D-Manp-(1→ and α-D-Gal-(1→. In vitro, antioxidant activity assays demonstrated that GSP-1a exhibited scavenging effects on hydroxyl radical (•OH), 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid radical cation (ABTS•+), and 2,2-diphenyl-1-picrylhydrazyl radical (DPPH•). Moreover, GSP-1a was found to alleviate H2O2-induced oxidative stress in HepG2 cells by reducing the levels of reactive oxygen species (ROS) and malondialdehyde (MDA), while enhancing the activities of superoxide dismutase (SOD). Furthermore, GSP-1a upregulated the mRNA expression of antioxidant enzymes such as Ho-1, Gclm, and Nqo1, and regulated the NRF2/KEAP1 and FNIP1/FEM1B pathways. The findings elucidated the structural types of GSP-1a and provided a reliable theoretical basis for its usage as a natural antioxidant in functional foods or medicine.

Protective effects and mechanism of Paecilomyces cicadae TJJ1213 intracellular polysaccharide against H2 O2 -induced PC12 cells damage

Oxidative stress is a key process in the development of neurodegenerative diseases. More attention is needed to screen natural antioxidants and explore pharmacological mechanisms. Natural product polysaccharides with no toxic side effects have powerful antioxidant activity. Two purified intracellular polysaccharide fractions (IPS1 and IPS2) from Paecilomyces cicadae TJJ1213 was isolated. Then, a model of H2 O2 -induced oxidative stress in PC12 cells was established to investigate the neuroprotective role of IPS and elucidate the potential protection mechanism. Results showed that IPS1 and IPS2 reduced reactive oxygen species (ROS) production, inhibited the leakage of lactate dehydrogenase (LDH) and Ca2+ and attenuated the expression of apoptotic proteins. In addition, western blots displayed that IPS1 and IPS2 significantly inhibited mitophagy induced by H2 O2 in PC12 cells via PINK/Parkin pathway. Therefore, IPS1 and IPS2 deserved further investigation as protective agents against neurodegenerative diseases.

Structure Characterization and Immunomodulatory Activity of Misgurnus anguillicaudatus Carbohydrates

Misgurnus anguillicaudatus, also known as oriental weather loach, is widely consumed and favored in East Asia due to its superior nutritional values and excellent flavor. In this study, a crude Misgurnus anguillicaudatus carbohydrates (MAC) was isolated from Misgurnus anguillicaudatus. Subsequently, two parts, which were named MAO and MAP, respectively, were separated from MAC, and their primary structures and immunomodulatory activity were investigated. The results showed that MAO had a molecular weight of 2854 Da, and principally consisted of arabinose (77.11%) and rhamnose (21.97%), together with minor levels of fucose (0.92%); MAP, with a molecular weight of 3873 Da, was mainly composed of fucose (87.55%) and a small amount of rhamnose (8.86%) and galactose (3.59%). The in vitro assay showed that MAC could significantly enhance the proliferation of macrophages without cytotoxicity and increase the production of immune substances (TNF-α, IL-6). Together with Western blot results, we speculated that MAC could stimulate RAW264.7 murine macrophage cells to secrete TNF-α and IL-6 through up-regulating TLR4-MAPK-p38 signaling pathways. The results indicated that MAC could be a potential immune agent and might provide meaningful information for further chain conformation and immune mechanism research.

A New Galactoglucomannan from the Mycelium of the Medicinal Parasitic Fungus Cordyceps cicadae and Its Immunomodulatory Activity In Vitro and In Vivo

A new galactoglucomannan (C-0-1) was purified from the medicinal parasitic fungus of Cordyceps cicadae using an anion-exchange column and gel permeation column. The results of high-performance liquid chromatography and high-performance gel permeation chromatography indicated that C-0-1 consists of galactose, glucose, and mannose in a ratio of 5:1:4 and has a molecular weight of 23.3 kDa. The combined structural elucidation analysis methods including partial acid hydrolysis, methylation analysis, and NMR experiments revealed that C-0-1 was a comb-like polysaccharide with a core structure including (1→2)-α-D-Manp residues in the backbone and branches at O-6 of the main chain. (1→4)-α-D-Glcp, (1→2)-β-D-Galf, (1→2,6)-β-D-Galf, and terminal β-Galf were located at the side chains. An in vitro experiment using RAW 264.7 cells indicated that C-0-1 exhibits good immunomodulatory activity by enhancing inducible nitric oxide synthase secretion and the production of some major inflammatory cytokines. On inhibiting the cytokine production using anti-pattern recognition receptors antibodies, it was revealed that the activation of macrophages is mainly carried out by C-0-1 through the mannose receptor. Toll-like receptor 4 and Toll-like receptor 2 were also involved in this identification process. An in vivo experiment on immunosuppressive mice treated with cyclophosphamide indicated that C-0-1 improves the secretion of serum-related cytokines (IFN-γ, TNF-α, IL-2, IL-4, and IL-10) and affects the balance of T helper cells Th1/Th2. Given the structural and bioactivity similarity between Cordyceps cicadae and Cordyceps sinensis, we can conclude that Cordyceps cicadae could be used as an important medicinal fungus like Cordyceps sinensis.

Preparation, structural characterization and neuroprotective effects to against H2O2-induced oxidative damage in PC12 cells of polysaccharides from Pleurotus ostreatus

Pleurotus ostreatus is one of the most common edible and medicinal fungi in life, and its polysaccharide has been a hot research topic in recent years. In this paper, a new intracellular polysaccharide component named P. ostreatus polysaccharide (POP-W) was obtained from the mycelium of P. ostreatus, and its structure was analyzed. The results showed that its molecular weight was Mw = 3.034 × 10³ kDa, and it did not contain protein and nucleic acid. POP-W was composed of mannose, glucose, galactose and xylose in a molar ratio of 40.34:47.60:7.97:4.09. The backbone of POP-W was α-D-Glcp(1→,→3,4)-α-D-Glcp(1→, →3,4)-α-D-Manp(1→,→3)-α -D-Galp(1→, →4)-α-D-Glcp(1→, →3)-α-D-Glcp(1→, →2)-β-D-Manp(1→, →4) -β-D-Xylp(1 →. SEM and TGA analysis showed the structure of POP-W and good thermal stability. In addition, POP-W showed significant antioxidant activity in vitro. More importantly, POP-W protected PC12 cells induced by H₂O₂ by inhibiting the contents of lactate dehydrogenase (LDH) and malondialdehyde (MDA) and increasing the levels of superoxide dismutase (SOD) and reduced glutathione (GSH). Western blot detection of Caspase-3, BAX, Bcl-2, PI3K/Akt protein expression. The results showed that POP-W inhibited the expression of caspase-3 and BAX, while promoting the expression of Bcl-2. In addition, POP-W can also promote the phosphorylation of Akt. In conclusion, POP-W pretreatment can protect PC12 cells from H₂O₂-induced oxidative damage through PI3K/Akt signaling pathway and regulation of apoptosis-related pathway proteins. It provided a theoretical basis for the practical application of the polysaccharide of P. ostreatus in production.

The polysaccharide from Camellia oleifera fruit shell enhances immune responses via activating MAPKs and NF-κB signaling pathways in RAW264.7 macrophages

Background

Macrophage plays an important role in innate immune responses by secreting immune molecules and phagocytosis. Camellia oleifera fruit shell, accounting for approximately 60% weight of the single C. oleifera fruit, is rich in polysaccharides and has several biological activities such as anti-oxidation, lipid regulation and anticancer. However, the immunomodulatory activity of the polysaccharide from C. oleifera fruit shells (CPS) has not been reported.

Objective

This study aimed to investigate the immunomodulatory activities and mechanisms of CPS in RAW264.7 macrophages.

Methods

The Methyl Thiazolyl Tetrazolium (MTT) method was used to evaluate the effect of CPS on the cell viability of RAW264.7 macrophages, and cell morphology was pictured using microscope. The production of immune-related molecules, including nitric oxide (NO), prostaglandin E2 (PGE2), tumor necrosis factor α (TNFα), interleukin (IL)-1β and IL-6, was detected by Griess assay and enzyme-linked immunosorbent assay (ELISA). The protein expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase 2 (COX2) and the phosphorylation level of mitogen-activated protein kinases (MAPKs) were analyzed through western blotting. The mRNA levels of related genes were tested using reverse transcription-polymerase chain reaction (RT-PCR). The nuclear translocation of nuclear factor-kappa B (NF-κB) was detected using immunofluorescence technology.

Results

The results indicated that CPS treatment stimulated the production of NO and PGE2 and significantly enhanced the protein expression of iNOS and COX2 with little effect on the cell morphology and viability. Also, the secretion and mRNA levels of TNFα were increased by the treatment of CPS. In addition, CPS treatment markedly upregulated the phosphorylation level of MAPKs including Extracellular Signal Regulated Kinase (ERK), P38, and c-Jun N-terminal Kinase (JNK) at different time points and caused the activation and nuclear translocation of NF-κB.

Conclusion

Our data implied that CPS exerts immunomodulatory activities by activating MAPKs and NF-κB signaling pathways in RAW264.7 macrophages.

Characterization and Immunological Activity of Exopolysaccharide from Lacticaseibacillus paracasei GL1 Isolated from Tibetan Kefir Grains

Two exopolysaccharide fractions (GL1-E1 and GL1-E2) of Lacticaseibacillus paracasei GL1 were isolated with the molecular weights of 3.9 × 105 Da and 8.2 × 105 Da, respectively. Both fractions possessed mannose, glucose, and galactose in molar ratios of 1.16:1.00:0.1, and 3.81:1.00:0.12, respectively. A structural arrangement of two fractions was proposed by methylation, one-dimensional and two-dimensional nuclear magnetic resonance experiments. The backbone of GL1-E1 consisted of →4)-α-D-Glcp(1→, →3,4)-α-D-Manp(1→, →3,6)-α-D-Manp(1→, →6)-α-D-Manp(1→, and →6)-α-D-Galp(1→ with α-D-Glcp at branching point. The backbone of GL1-E2 consisted of →4)-α-D-Glcp(1→, →3,4)-α-D-Manp(1→, →3,6)-α-D-Manp(1→, →6)-α-D-Manp(1→, →6)-α-D-Galp(1→, and →4)-β-D-Manp(1→, and the side chain also consisted of α-D-Manp residue. In addition, the differential scanning calorimetry (DSC) analysis indicated that both GL1-E1 and GL1-E2 had good thermal stability. Furthermore, the two fractions could promote the viability of RAW264.7 cells and exert an immunomodulatory role by enhancing phagocytosis, increasing nitric oxide (NO) release and promoting the expression of cytokines.

Optimisation of the production of a selenium-enriched polysaccharide from Cordyceps cicadae S1 and its structure and antioxidant activity

The fermentation medium of a newly identified Cordyceps cicadae S1 was optimized by response surface methodology, with the optimal medium containing sucrose (80 g/L), yeast powder (60 g/L), KH₂PO₄ (5 g/L), MgSO₄·7H₂O (1 g/L) and Na₂SeO₃ (0. 1 g/L). Under these conditions, the extracellular polysaccharide yield was 8.09 g/L. A novel selenium-enriched polysaccharide (PACI-1) was isolated from Cordyceps cicadae, purified and identified as a homofructose polysaccharide with a low average molecular weight of 9.95 × 10³ Da. The fine structure of PACI-1 was analyzed using NMR, CD, and AFM. Additionally, the in vitro antioxidant results showed that the PACI-1 had stronger antioxidant capacity than natural polysaccharides. These results provided a candidate strain for producing selenium polysaccharide and a new polysaccharide from C. cicadae, which showed good antioxidant activity.

Structural characterization and immunoregulatory activity of a neutral polysaccharide from the roots of Apocynum venetum L

The structural characteristics and immunoregulatory activities of neutral heteropolysaccharide (AVRP-N) separated from the roots of Apocynum venetum L. were extensively investigated. The results showed that the weight average molecular mass (Mw) of AVRP-N was 6.430 × 10³ Da. Moreover, the backbone is composed of natural acetylated (1 → 4)-β-D-Man and (1 → 5)-α-L-Ara domains. The mannan is composed of →4)-β-D-Manp-(1→, →4)-β-D-Glcp-(1→, and the terminal group α-D-Galp-(1→ attached to →4,6)-β-D-Manp-(1→ at O-6. Araban is composed of →5)-α-L-Araf-(1→; the terminal group α-L-Araf-(1→attached to→2,3,5)-α-L-Araf-(1→ at O-2, O-3 and →3,5)-α-L-Araf-(1→ at O-3. In addition, the senior structure shows that AVRP-N has a triple-helix conformation. Furthermore, AVRP-N exhibited immunomodulatory effects, which could significantly regulate the proliferation of mouse splenic lymphocytes by enhancing the secretion of the cytokines (IFN-γ, IL-2, IL-4, and IL-10). Our results provide new structural and immunoregulatory information for natural polysaccharides derived from Apocynum venetum L.

Efficient biosynthesis of exopolysaccharide in Candida glabrata by a fed-batch culture

Polysaccharides are important natural biomacromolecules. In particular, microbial exopolysaccharides have received much attention. They are produced by a variety of microorganisms, and they are widely used in the food, pharmaceutical, and chemical industries. The Candida glabrata mutant 4-C10, which has the capacity to produce exopolysaccharide, was previously obtained by random mutagenesis. In this study we aimed to further enhance exopolysaccharide production by systemic fermentation optimization. By single factor optimization and orthogonal design optimization in shaking flasks, an optimal fermentation medium composition was obtained. By optimizing agitation speed, aeration rate, and fed-batch fermentation mode, 118.6 g L⁻¹ of exopolysaccharide was obtained by a constant rate feeding fermentation mode, with a glucose yield of 0.62 g g⁻¹ and a productivity of 1.24 g L⁻¹ h⁻¹. Scaling up the established fermentation mode to a 15-L fermenter led to an exopolysaccharide yield of 113.8 g L⁻¹, with a glucose yield of 0.60 g g⁻¹ and a productivity of 1.29 g L⁻¹ h⁻¹.

Effects of Ultrasound Modification with Different Frequency Modes on the Structure, Chain Conformation, and Immune Activity of Polysaccharides from Lentinus edodes

Highlights

Abstract

The aim of this study was to investigate the effects of ultrasound with different frequency modes on the chemical structure, chain conformation, and immune activity of lentinan from Lentinus edodes; the structure–activity relationship of lentinan was also discussed. The results showed that, compared with original lentinan (extracted using hot water), although ultrasonic treatment did not change the monosaccharide composition and main functional groups of lentinan, it significantly changed its chain conformation. Especially at 60, 40/60, and 20/40/60 kHz, according to atomic force microscopy and solution chain conformation parameters, lentinan transformed from a rigid triple-helix chain to a flexible single-helix chain, and the side-chain was severely broken. Under this condition, lentinan had the worst immune activity. However, at 20/40 and 20/60 kHz, the rigid triple-helix chain transformed into a loose and flexible triple-helix chain, showing the strongest immune activity. These results indicated that dual-frequency ultrasound had significant effects on the conformation of lentinan, and the conformation characteristics of polysaccharide chain such as spiral number, stiffness and flexibility, and side-chain played an important role in immune activity. This study shows the great potential of ultrasound with different frequency modes in carbohydrate food processing, which may have important reference value and practical significance.

Structural Characteristics, Antioxidant, and Immunostimulatory Activities of an Acidic Polysaccharide from Raspberry Pulp

The extraction and characterization of new bioactive plant-derived polysaccharides with the potential for use as functional foods and medicine have attracted much attention. In the present study, A novel acidic polysaccharide (RPP-3a) with a weight-average molecular weight (Mw) of 88,997 Da was isolated from the raspberry pulp. RPP-3a was composed of rhamnose, arabinose, galactose, glucose, mannose, and galacturonic acid at a molar ratio of 13.1:28.6:16.8:1.4:6.2:33.9. Structural analysis suggested that the RPP-3a backbone was composed of repeating units of →4)-β-Galp-(1→3,4)-α-Rhap-(1→[4)-α-GalAp-(1→4)-α-GalAp-(1→]_n with branches at the C-4 position of rhamnose. The side chain of RPP-3a, containing two branch levels, was comprised of α-Araf-(1→, →5)-α-Araf-(1→, →3,5)-α-Araf-(1→, →3)-β-Galp-(1→, →3,6)-β-Galp-(1→, →4)-β-Glcp-(1→, and →2,6)-α-Manp-1→ residues. RPP-3a exhibited moderate reducing power and strong hydroxyl and superoxide anion radical scavenging abilities. RPP-3a significantly promoted the viability of RAW264.7 macrophages by increasing the production of nitric oxide (NO), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and interleukin-1β (IL-1β) at both the expression and transcriptional levels. In summary, the immunostimulatory and antioxidant activities make RPP-3a a viable candidate as a health-beneficial functional dietary supplement.

Structure of a unique fucose-containing exopolysaccharide from Sayram ketteki yoghurt and its anti-MRSA biofilm effect

In this work, we reported an in situ exopolysaccharide (in situ-EPS1) containing rare fucose produced by Lactobacillus helveticus MB2-1 in Sayram ketteki yoghurt, which made it unique. Its fine structure was characterized by GPC, HPLC, FT-IR, GC-MS,¹HNMR and ¹³CNMR together with two-dimensional (2D) NMR spectra. The results revealed that in situ-EPS1 was a new heteropolysaccharide with molecular weight of 1.06 × 10⁵ Da, and was composed of mannose, rhamnose, glucose, galactose and fucose with the following repeating units. Furthermore, the in situ-EPS1 exhibited significant antibiofilm effect against Methicillin-resistant Staphylococcus aureus (MRSA). Notably, the in situ-EPS1 did not interfere with the planktonic growth of MRSA strain, whereas inhibited its cell metabolic activity and the transcription of genes related to biofilm formation. This unique antibiofilm but non-antibacterial mechanism supposedly prevented the development of bacterial drug resistance, which may open a new door to fight against these drug-resistant microorganisms.

Exopolysaccharide from the yeast Papiliotrema terrestris PT22AV for skin wound healing

INTRODUCTION

Exopolysaccharides (EPSs) are high-value functional biomaterials mainly produced by bacteria and fungi, with nutraceutical, therapeutic and industrial potentials.

OBJECTIVES

This study sought to characterize and assess the biological properties of the EPS produced by the yeast Papiliotrema terrestris PT22AV.

METHODS

After extracting the yeast's DNA and its molecular identification, the EPS from P. terrestris PT22AV strain was extracted and its physicochemical properties (structural, morphological, monosaccharide composition and molecular weight) were characterized. The EPS's in vitro biological activities and in vivo wound healing potential were also evaluated.

RESULTS

The obtained EPS was water-soluble and revealed an average molecular weight (M_w) of 202 kDa. Mannose and glucose with 97% and 3% molar percentages, respectively, constituted the EPS. In vitro antibacterial activity analysis of the extracted EPS exhibited antibacterial activity (>80%) against Escherichia coli, Staphylococcus aureus, and Staphylococcus epidermidis at a concentration of 2 mg/mL. The EPS showed cytocompatibility against the human fibroblast and macrophage cell lines and the animal studies showed a dose-dependent wound healing capacity of the EPS with higher wound closure at 10 mg/mL compared to negative and positive control after 14 days.

CONCLUSION

The EPS from P. terrestris PT22AV could serve as a promising source of biocompatible macromolecules with potential for skin wound healing.

Isolation, Structural Characterization and Macrophage Activation Activity of an Acidic Polysaccharide from Raspberry Pulp

The discovery of safe and effective plant polysaccharides with immunomodulatory effects has become a research hotspot. Raspberry is an essential commercial fruit and is widely distributed, cultivated, and consumed worldwide. In the present study, a homogeneous acidic polysaccharide (RPP-2a), with a weight-average molecular weight (Mw) of 55582 Da, was isolated from the pulp of raspberries through DEAE-Sepharose Fast Flow and Sephadex G-200 chromatography. RPP-2a consisted of rhamnose, arabinose, galactose, glucose, xylose, galacturonic acid and glucuronic acid, with a molar ratio of 15.4:9.6:7.6:3.2:9.1:54.3:0.8. The results of Fourier transform infrared spectroscopy (FT-IR), gas chromatography-mass spectrometer (GC-MS), 1D-, and 2D-nuclear magnetic resonance (NMR) analyses suggested that the backbone of RPP-2a was primarily composed of →2)-α-L-Rhap-(1→, →2,4)-α-L-Rhap-(1→, →4)-α-D-GalAp-(1→, and →3,4)-α-D-Glcp-(1→ sugar moieties, with side chains of α-L-Araf-(1→, α-L-Arap-(1→, and β-D-Galp-(1→3)-β-D-Galp-(1→ residues linked to the O-4 band of rhamnose and O-3 band of glucose residues. Furthermore, RPP-2a exhibited significant macrophage activation activity by increasing the production of nitric oxide (NO), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin-1β (IL-1β), and the expression of inducible nitric oxide synthase (iNOS) and cytokines at the transcriptional level in RAW264.7 cells. Overall, the results indicate that RPP-2a can be utilized as a potential natural immune-enhancing agent.

Structure characterization, antioxidant capacity, rheological characteristics and expression of biosynthetic genes of exopolysaccharides produced by Lactococcus lactis subsp. lactis IMAU11823

Exopolysaccharides (EPSs) from lactic acid bacteria have special functions and complex structures, but the function and structure of EPSs of the important dairy starter, Lactococcus (L.) lactis subsp. lactis, are less known. This study investigated the cytotoxicity, antioxidant capacities, rheological characteristics, chemical structure and expression of biosynthetic genes of EPSs of the L. lactis subsp. lactis IMAU11823. The EPSs showed strong reducing power and no cytotoxicity. EPS-1 comprised glucose and mannose (molar ratio of 7.01: 1.00) and molecular weight was 6.10 × 10⁵ Da, while EPS-2 comprised mannose, glucose and rhamnose (7.45: 1.00: 2.34) and molecular weight was 2.93 × 10⁵ Da. EPS-1 was a linear structure comprised two sugar residues, while EPS-2 was more complex, non-linear, and comprised eight sugar residues. In additions, our study proposed an EPS biosynthesis model for the IMAU11823 strain. The current findings have broadened the understanding of the formation, structure and function of complex EPSs of IMAU11823.

Comparison of water- and alkali-extracted polysaccharides from Fuzhuan brick tea and their immunomodulatory effects in vitro and in vivo

In the present study, the purpose is to compare the effect of water extraction and alkali-assisted extraction on the structural characteristics and immunomodulatory activity of polysaccharides from Fuzhuan brick tea (FBTPs). The results indicated that water-extracted FBTPs (W-FBTPs) and alkali-extracted FBTPs (A-FBTPs) had similar molecular weights but different monosaccharide compositions, of which A-FBTPs had a higher yield and uronic acid groups corresponding to galacturonic acid (GalA). Moreover, A-FBTPs had stronger ability to promote phagocytic capacity, acid phosphatase activity and nitric oxide (NO) secretion in macrophages in vitro. In the in vivo study, A-FBTPs exhibited a promising effect to adjust the immune imbalance by enhancing the body features, antioxidant activities, immune response and intestinal mucosal barrier in cytoxan (CTX)-induced immunosuppressive mice. Besides, A-FBTP supplementation effectively improved CTX-induced gut microbiota dysbiosis, including promoting the abundance of beneficial bacteria (e.g., Lactobacillus) and short chain fatty acid (SCFA)-producing bacteria (e.g., Lachnospiraceae, Prevotellaceae and Ruminococcaceae), along with reducing the growth of potentially pathogenic microbes (e.g., Desulfovibrionaceae and Helicobacter). These findings suggested that alkaline extraction might be a promising way to obtain high-quality acidic polysaccharides from Fuzhuan brick tea (FBT), and A-FBTPs could be developed as novel potential prebiotics and immunomodulators for further application in food formulations.