Structure, chain conformation, and immunomodulatory activity of the polysaccharide purified from Bacillus Calmette Guerin formulation

Glucan polysaccharides isolated from Lactarius hatsudake Tanaka mushroom: Structural characterization and in vitro bioactivities

Commercially available mushroom polysaccharides have found widespread use as adjuvant tumor treatments. However, the bioactivity of polysaccharides in Lactarius hatsudake Tanaka (L. hatsudake), a mushroom with both edible and medicinal uses, remains relatively unexplored. To address this gap, five L. hatsudake polysaccharides with varying molecular weights were isolated, named LHP-1 (898 kDa), LHP-2 (677 kDa), LHP-3 (385 kDa), LHP-4 (20 kDa), and LHP-5 (4.9 kDa). Gas chromatography-mass spectrometry, nuclear magnetic resonance, and atomic force microscopy, etc., were employed to determine their structural characteristics. The results confirmed that spherical aggregates with amorphous flexible fiber chains dominated the conformation of the LHP. LHP-1 and LHP-2 were identified as glucans with α-(1,4)-Glcp as the main chain; LHP-3 and LHP-4 were classified as galactans with varying molecular weights but with α-(1,6)-Galp as the main chain; LHP-5 was a glucan with β-(1,3)-Glcp as the main chain and β-(1,6)-Glcp connecting to the side chains. Significant differences were observed in inhibiting tumor cell cytotoxicity and the antioxidant activity of the LHPs, with LHP-5 and LHP-4 identified as the principal bioactive components. These findings provide a theoretical foundation for the valuable use of L. hatsudake and emphasize the potential application of LHPs in therapeutic tumor treatments.

A fungal polysaccharide from Fomitopsis officinalis as a multi-target molecule to combat cancer

Some macrofungi have a long history of being used as traditional or folk medicines, making significant contributions to human health. To discover bioactive molecules with potential anticancer properties, a homogeneous heteropolysaccharide (FOBP90-1) was purified from the medicinal macrofungus Fomitopsis officinalis. FOBP90-1 was found to have a molecular weight of 2.87 × 104 g/mol and mainly consist of →6)-α-d-Galp-(1→, →2,6)-α-d-Galp-(1→, →3)-α-l-Fucp-(1→, →6)-β-d-Glcp-(1→, α-d-Manp-(1→, and 3-O-Me-α-l-Fucp-(1→ according to UV, FT-IR, methylation analysis, and NMR data. In addition to its structural properties, FOBP90-1 displayed anticancer activity in zebrafish models. The following mechanistic analysis discovered that the in vivo antitumor effect was linked to immune activation and angiogenesis inhibition. These effects were mediated by the interactions of FOBP90-1 with TLR-2, TLR-4, PD-L1, and VEGFR-2, as determined through a series of experiments involving cells, transgenic zebrafish, molecular docking simulations, and surface plasmon resonance (SPR). All the experimental findings have demonstrated that FOBP90-1, a purified fungal polysaccharide, is expected to be utilized as a cancer treatment agent.

Sensitive, precise fingerprint profiling for monosaccharide analysis of Bacillus Calmette-Guérin polysaccharide and nucleic acid isolates

A sensitive and precise HPLC-DAD method with pre-column PMP derivatization was established and validated, for analyzing the polysaccharides in Bacillus Calmette-Guérin polysaccharide and nucleic acid (BCG-PSN) isolates, after acid hydrolysis. And the HPLC fingerprint profiling was used to analyze its monosaccharide composition. The monosaccharide concentration-peak area calibration curve was of good linearity (R2 > 0.99), over the range of 0.016-0.08 mg/mL for mannose or 0.24-1.20 mg/mL for glucose, with high recovery of 93-105 % for quality control samples. The intra-day RSD values of mannose and glucose concentration were less than 2.5 % and 2.1 %, respectively, and their inter-day RSD values were less than 4.3 % and 2.2 %, respectively, and remained stable for up to 14 days. This method also remained durable against changes in chromatographic parameters, but it's susceptible to the flow rate of mobile phase. Additionally, the method was applied to analyze the content of mannose and glucose in 22 batches BCG-PSN powder and 17 batches BCG-PSN injection. The results showed that the HPLC-DAD fingerprint spectra of all the BCG-PSN powder and BCG-PSN injection samples had a high degree of similarity, with the similar indexes up to 0.999 and 0.998, respectively. The HPLC-DAD method with pre-column PMP derivatization is highly rapid, effective, visual, and accurate for determination of monosaccharide contents. The validated method was successfully applied to the analysis of polysaccharide in both BCG-PSN powder and injection.

An antitumor fungal polysaccharide from Fomitopsis officinalis by activating immunity and inhibiting angiogenesis

Macrofungi, a class of unique natural resources, are gaining popularity owing to their potential therapeutic benefits and edibility. From Fomitopsis officinalis, a medicinal macrofungus with anticancer activity, a homogeneous heteropolysaccharide (FOBP50-1) with a molecular weight of 2.21 × 104 g/mol has been extracted and purified. FOBP50-1 was found to be composed of 3-O-methylfucose, fucose, mannose, glucose, and galactose with a ratio of 1: 6.5: 4.4: 8.1: 18.2. The sugar fragments and structure of FOBP50-1 were investigated, which included →6)-α-d-Galp-(1→, →2,6)-α-d-Galp-(1→, →3)-α-l-Fucp-(1→, α-d-Glcp-(1→, →3)-β-d-Manp-(1→, →6)-β-d-Manp-(1→, 3-O-Me-α-l-Fucp-(1→, according to the UV, FT-IR, GC-MS, and NMR data. Besides the structure elucidation, FOBP50-1 showed promising antitumor activity in the zebrafish assays. The following mechanism examination discovered that FOBP50-1 interacted with TLR-4, PD-1, and VEGF to activate immunity and inhibit angiogenesis according to a series of cell, transgenic zebrafish, and surface plasmon resonance (SPR) experiments. The KD values indicating the association of FOBP50-1 with TLR-4, PD-1, and VEGF, were 4.69 × 10-5, 7.98 × 10-6, 3.04 × 10-6 M, respectively, in the SPR experiments. All investigations have demonstrated that the homogenous fungal polysaccharide FOBP50-1 has the potential to be turned into a tumor immunotherapy agent.

Structural characterization and anti-oxidative activity for a glycopeptide from Ganoderma lucidum fruiting body

A water-soluble glycopeptide (named GL-PWQ3) with a molecular weight (Mw) of 2.40 × 104 g/mol was isolated from Ganoderma lucidum fruiting body by hot water extraction, membrane ultrafiltration, and gel column chromatography, which mainly consisted of glucose and galactose. Based on the methylation, FT-IR, 1D, and 2D NMR analysis, the polysaccharide portion of GL-PWQ3 was identified as a glucogalactan, which was comprised of unsubstituted (1,6-α-Galp, 1,6-β-Glcp, 1,4-β-Glcp) and monosubstituted (1,2,6-α-Galp and 1,3,6-β-Glcp) in the backbone and possible branches that at the O-3 position of 1,3-Glcp and T-Glcp, and the O-2 position of T-Fucp, T-Manp or T-Glcp. The chain conformational study by SEC-MALLS-RI and AFM revealed that GL-PWQ3 was identified as a highly branched polysaccharide with a polydispersity index of 1.25, and might have compact sphere structures caused by stacked multiple chains. Moreover, the GL-PWQ3 shows strong anti-oxidative activity in NRK-52E cells. This study provides a theoretical basis for further elucidating the structure-functionality relationships of GL-PWQ3 and its potential application as a natural antioxidant in pharmacotherapy as well as functional food additives.

Physicochemical characterization, digestion profile and gut microbiota regulation activity of intracellular polysaccharides from Chlorella zofingiensis

A number of studies have shown that the polysaccharides from microalgae exhibit diverse biological activities, however, little is known about their digestibility and impact on human gut microbiota. In this study, a simulating digestion and fermentation system were established to investigate the digestibility and fermentation of intracellular polysaccharides from Chlorella zofingiensis (CZIP-S3). The results indicated that CZIP-S3 is a macromolecular polysaccharide composed of mannose, glucose, galactose and rhamnose, consisting of a main chain and two branched repeating units. CZIP-S3 could not be digested in the upper gastrointestinal tract. However, CZIP-S3 could be metabolized into smaller molecules by the gut microbiota. The pH values continuously decrease during fermentation, whereas, the amount of short-chain fatty acids steadily increase. Furthermore, CZIP-S3 could modulate the composition of gut microbiota, via lowering the ratio of Firmicutes/Bacteroidetes and increasing the relative abundance of Bacteroides, Bifidobacterium and Akkermansia. The data suggested that CZIP-S3 could potentially be used as an ingredient for functional foods or prebiotics to improve human health by promoting the relative abundances of beneficial bacteria.

Purification, Structural Characterization, and Antitumor Activity of a Polysaccharide from Perilla Seeds

A previous study found that a crude Perilla seed polysaccharide (PFSP) fraction exhibited obviously antitumor activity; however, the structural characterization and antitumor properties of this polysaccharide remain unclear. In this study, the PFSP was extracted and purified via combined column chromatography, and the structure of a single polysaccharide fraction was characterized by methylation, IC, GC-MS, NMR, and AFM. The results demonstrated that the efficient antitumor polysaccharide fraction PFSP-2-1 was screened from PFSP with a relative molecular weight of 8.81 × 106 Da. The primary structure of the PFSP main chain was →1)-Araf-(5→, →1,3)-Galp-(6→, →1)-Galp-(6→, →1,3)-Araf-(5→ and →1)-Xylp-(4→, and that of the side chains was →1)-Arap, →1,3)-Galp-(6→, →1)-Araf and →1)-Glcp-(4→, →1)-Galp-(3→ and →1)-Glcp, leading to a three-dimensional helical structure. CCK-8 experiments revealed that PFSP-2-1 significantly inhibited the growth of human hepatocellular carcinoma cells in vitro (p < 0.05), and its inhibitory effect positively correlation with the concentration of PFSP-2-1, and when the concentration of PFSP-2-1 was 1600 µg/mL, it showed the highest inhabitation rate on three hepatocellular carcinoma cells (HepG-2, Hep3b, and SK-Hep-1), for which the survival rates of HepG-2, Hep3b, and SK-Hep-1 were 53.34%, 70.33%, and 71.06%. This study clearly elucidated the structure and antitumor activity of PFSP-2-1, which lays a theoretical foundation for revealing the molecular mechanism of antitumor activity of Perilla seed polysaccharides and provides an important theoretical basis for the development of high-value Perilla.

Application of microneedles combined with dendritic cell-targeted nanovaccine delivery system in percutaneous immunotherapy for triple-negative breast cancer

This work aims at developing a strategy to activate the antigen-presenting cells to enhance the effect of immunotherapy in triple-negative breast cancer (TNBC) through the dissolving microneedle patch (DMNP). In present study, mannosylated chitosan (MCS) nanoparticles (NPs) were designed to target dendritic cells (DCs), and the immunotherapy effect was enhanced by the adjuvant Bacillus Calmette-Guerin polysaccharide (BCG-PSN), achieving the purpose of transdermal immunotherapy for TNBC. Vaccination studies with mice demonstrated that MCS NPs effectively induce DCs maturation in the tumor-draining lymph nodes to stimulate strong immune responses in TNBC. Overall, chitosan-based DMNPs with complex adjuvant constituted a new potent transdermal vaccine delivery platform capable of exploiting more DCs in the skin for effective immunization.

Effects of Solid Fermentation on Polygonatum cyrtonema Polysaccharides: Isolation, Characterization and Bioactivities

Polygonati Rhizoma is a widely used traditional Chinese medicine (TCM) with complex pre-processing steps. Fermentation is a common method for processing TCM to reduce herb toxicity and enhance their properties and/or produce new effects. Here, in this study, using Bacillus subtilis and Saccharomyces cerevisiae, we aimed to evaluate the potential application of solid fermentation in isolating different functional polysaccharides from Polygonatum cyrtonema Hua. With hot water extraction, ethanol precipitation, DEAE anion exchange chromatography and gel filtration, multiple neutral and acidic polysaccharides were obtained, showing different yields, content, compositions and functional groups after fermentation. Combining in vitro experiments and in vivo aging and immunosuppressed mouse models, we further compared the antioxidant and immunomodulating bioactivities of these polysaccharides and found a prominent role of a natural polysaccharide (BNP) from fermented P. cyrtonema via Bacillus subtilis in regulating intestinal antioxidant defense and immune function, which may be a consequence of the ability of BNP to modulate the homeostasis of gut microbiota. Thus, this work provides evidence for the further development and utilization of P. cyrtonema with fermentation, and reveals the potential values of BNP in the treatment of intestinal disorders.

Regulation strategy, bioactivity, and physical property of plant and microbial polysaccharides based on molecular weight

Structural features affect the bioactivity, physical property, and application of plant and microbial polysaccharides. However, an indistinct structure-function relationship limits the production, preparation, and utilization of plant and microbial polysaccharides. Molecular weight is an easily regulated structural feature that affects the bioactivity and physical property of plant and microbial polysaccharides, and plant and microbial polysaccharides with a specific molecular weight are important for exerting their bioactivity and physical property. Therefore, this review summarized the regulation strategies of molecular weight via metabolic regulation; physical, chemical, and enzymic degradations; and the influence of molecular weight on the bioactivity and physical property of plant and microbial polysaccharides. Moreover, further problems and suggestions must be paid attention to during regulation, and the molecular weight of plant and microbial polysaccharides must be analyzed. The present work will promote the production, preparation, utilization, and investigation of the structure-function relationship of plant and microbial polysaccharides based on their molecular weight.

Intra-articular delivery system of methotrexate for rheumatoid arthritis therapy: An in-suit thermosensitive comprehensive gel of polysaccharide from Aconitum carmichaelii Debx

The polysaccharides (FP) extracted from the lateral roots of Aconitum carmichaelii Debx. (Fuzi) are natural compounds, which have effective therapy for rheumatoid arthritis (RA). Methotrexate (MTX) is the first-line drug for RA, but its application is greatly limited to the toxicity in liver and kidney and drug resistance. In this study, an attempt is made to apply oxidized FP (OFP) as a polymer carrier based on intra-articular delivery system loaded MTX. The FP could be developed and used as comprehensive gel carriers with biocompatibility and degradability for therapy of RA. Firstly, OFP-chitosan-poloxamer 407 (OFP-CS-F407-MTX) gel was prepared by natural non-toxic cross-linking agents. Physicochemical characterization was performed by using ¹H NMR and FTIR spectroscopic techniques to assess the successful functionalization of OFP. TGA, SEM and rheological experiment of OFP-CS-F407-MTX gel were investigated. Notably, we loaded MTX into OFP-CS-F407-MTX gel which had remarkable therapeutic efficacy and biosafety for RA. Based on advantages of intra-articular injection of OFP-CS-F407-MTX gel releasing MTX, it modulated proinflammatory cytokines by down-regulating TNF-α, IL-6 and IL-1β expression. Therefore, OFP-CS-F407-MTX in situ gel delivery system can potentially reduce systemic toxicity and irritation of oral administration of MTX but give a controlled release of drug for a long period of time.

Influenza Virus Infection Increases Host Susceptibility To Secondary Infection with Pseudomonas aeruginosa, and This Is Attributed To Neutrophil Dysfunction through Reduced Myeloperoxidase Activity

Secondary bacterial infection greatly increased the morbidity and mortality of influenza virus infection. To investigate the underlying mechanism by which influenza impairs the pulmonary defense against secondary Pseudomonas aeruginosa (P. aeruginosa) infection, we established a lethal mouse model in which to study secondary P. aeruginosa infection after influenza virus infection. We found a significant increase in host susceptibility to a secondary infection with P. aeruginosa in mice after an influenza virus infection, and this was accompanied by severe immunopathology and pulmonary inflammation. Importantly, we demonstrated that neutrophils were essential for P. aeruginosa clearance in secondarily infected mice. Further, we revealed that influenza impaired the phagocytosis and digestion functions of pulmonary neutrophils for P. aeruginosa clearance. We identified that the activity of reactive oxygen species (ROS) and the myeloperoxidase (MPO) activity of neutrophils in the lungs played an important role in antibacterial host defense in influenza-infected lungs. Hereby, influenza virus infection causes deficient MPO activity in neutrophils, and this contributes to the increased susceptibility to secondary P. aeruginosa infection. Treatment with Bacillus Calmette-Guerin polysaccharide nucleic acid (BCG-PSN) prior to secondary P. aeruginosa infection may improve the function of neutrophils, resulting in significantly reduced lethality during secondary P. aeruginosa infection. We also demonstrated that treatment with anti-influenza immune serum during the early stage of an influenza virus infection could decrease the disease severity of secondary P. aeruginosa infection. Our findings suggest that improving the MPO activity of neutrophils may provide a therapeutic strategy for viral-bacterial coinfection.

IMPORTANCE A secondary bacterial infection, such as that of P. aeruginosa, often occurs after a pulmonary virus infection and contributes to severe disease. However, the underlying mechanisms responsible for viral-bacterial synergy in the lung remain largely unknown. In this study, we reported that influenza virus infection increases a host’s susceptibility to secondary infection by P. aeruginosa by reducing the MPO activity of neutrophils. We also demonstrated that treatment with BCG-PSN or anti-influenza immune serum prior to secondary P. aeruginosa infection can reduce the disease severity. Our findings suggest that improving the MPO activity of neutrophils may provide a therapeutic strategy for viral-bacterial coinfection.

Characterization and protective effect against ultraviolet radiation of a novel exopolysaccharide from Bacillus marcorestinctum QDR3-1

Although exopolysaccharide (EPS) has been applied to various fields, EPS for UVR-mediated oxidative stress repair still needs further exploration. In this study, a novel EPS was isolated from the fermentation medium of Bacillus sp. QDR3-1 and its yield was 4.8 g/L (pH 8.0, 12 % glucose, 30 °C and 6 % NaCl). The pure fraction (named EPS-M1) was purified by DEAE-cellulose and Sephadex G-100 column. EPS-M1 was a heteropolysaccharide composed of Man, Glc, Gal, and Fuc with a molecular weight of 33.8 kDa. Scanning electron microscopy (SEM) observed a rough surface and reticular structure of EPS-M1, and EPS-M1 formed spherical aggregates in aqueous solution observed in atomic force microscopy (AFM). Thermal analysis revealed that the degradation temperature of EPS-M1 was 306 °C. Moreover, methylation and NMR analysis determined that EPS-M1 was consisted of →3)-Manp-(1→, →2,6)-Manp-(1→, →4,6)-Glcp-(1→, →3)-Glcp-(1→, →4)-Galp-(1→, →4)-Fucp-(1→, and T-Manp-(1→. Furthermore, the cytotoxicity and the repair ability of UVR-mediated cell damage of EPS-M1 were studied with L929 cells. The results showed that EPS-M1 had good biocompatibility and it could mitigate UVR-mediated cell damage by regulating the levels of cellular reactive oxygen species (ROS), depolarization of mitochondrial membrane potential (MMP) and Caspase-3/7 activity. Overall, the structure analysis and the protective effects of EPS against L929 cells exposed to UVR provided an experimental basis for EPS in practical applications.

Detailed Structural Analysis of the Immunoregulatory Polysaccharides from the Mycobacterium Bovis BCG

Bacillus Calmette-Guérin polysaccharide and nucleic acid (BCG-PSN), extracted from Mycobacterium bovis, is an immunoregulatory medicine commonly used in clinic. However, the structural characteristics and potential pharmacological efficacy of the polysaccharides from BCG-PSN remain unclear. Herein, two polysaccharides (BCG-1 and BCG-2) were purified and their structures were characterized. Monosaccharide composition analysis combined with methylation analysis and NMR data indicated that BCG-1 and BCG-2 were an α-D-(1→4)-mannan with (1→2)-linked branches, and an α-D-(1→4)-glucan with (1→6)-linked branches, respectively. Herein, the mannan from BCG-PSN was first reported. Bioactivity assays showed that BCG-1 and BCG-2 dose-dependently and potently increased the production of inflammatory mediators (NO, TNF-α, IL-6, IL-1β, and IL-10), as well as their mRNA expressions in RAW264.7 cells; both have similar or stronger effects compared with BCG-PSN injection. These data suggest that BCG-1 and BCG-2 are very likely the active ingredients of BCG-PSN.

Effects of steam on polysaccharides from Polygonatum cyrtonema based on saccharide mapping analysis and pharmacological activity assays

Background

Polygonatum cyrtonema, one of origins of Polygonata Rhizoma (HuangJing in Chinese), is traditionally steamed repeatedly before being used as herbal medicine in China. However, there has no standard for steaming of HuangJing. Therefore, a comprehensive study for effects of steam on polysaccharides from Polygonatum cyrtonema based on saccharide mapping, a powerful method developed for polysaccharides analysis, and pharmacological activity are still necessary, which is helpful to explore the effect of steam on the physiochemical and biological activities of its polysaccharides and develop steaming standard of Polygonatum cyrtonema.

Methods

To explore the effect of steam on physiochemical and biological activities of P. cyrtonema polysaccharides (PCP), six polysaccharides named PCP0, PCP1, PCP2, PCP3, PCP4 and PCP5 were extracted from the herb consecutively steamed for 0–5 times, respectively. Their molecular weight distribution, monosaccharide composition and PACE fingerprints were investigated through HPSEC-MALLS-RID, HPAEC-PAD and saccharide mapping based on polysaccharides analysis by using carbohydrate gel electrophoresis (PACE) and HPTLC, respectively. In addition, their antioxidant ability and immunostimulatory activities on RAW 264.7 cells in terms of NO production and phagocytosis were compared.

Results

Results suggested that molecular weights could be changed during steam, which increased by first steaming and then decreased with further steaming though all polysaccharides’ molecular weights were 10⁵-10⁷ Da. They all showed irregularly spherical conformation in aqueous solution based on AFM imaging. Their monosaccharide composition and PACE fingerprints were significantly different after steaming, i.e., galactose increased while glucose and mannose decreased, and β-1,4-Galp appeared while β-1,4-Manp increased, after steaming. Steamed PCP significantly increased scavenging activity against ABTS radicals, while PCP0 had the best immunostimulatory effect on RAW 264.7 in terms of NO production and phagocytosis.

Conclusions

In summary, steam significantly affected the chemical composition and bioactivities of polysaccharides from P. cyrtonema. Considering the balance beneficial effects of steaming on antioxidant and immunopotentiation activities of PCP, 2 times of continuous steam is the optimal choice under the given conditions.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13020-022-00650-3.

Structural characteristics and immunostimulatory activity of sea cucumber tendon polysaccharides in cyclophosphamide-induced Balb/c mice

Sea cucumber tendon, one of the main parts of sea cucumber viscera, is widely accepted as a waste residue. In this study, a sea cucumber tendon polysaccharide (SCTPII) was purified from sea cucumber tendons and its primary structures and immunomodulatory activity were investigated. SCTPII is a triple-helix conformation homogeneous polysaccharide with a molecular weight of 3.97 × 10⁶ Da that consists of glucose and fucose with molar ratios of 92.09% and 7.91% with high thermostability. In vivo tests on immunosuppressed Balb/c mice revealed that compared with the model group, the proliferation of T cells and B cells in splenic lymphocytes of mice in the high-dose group was significantly improved by 0.92 times and 5.14 times, respectively. Additionally, SCTPII could improve the proliferation ability and phagocytosis of macrophages, as well as promoting the expression of IL-6, TNF-α and IFN-γ and enhancing the intestinal physical barrier function by increasing the protein expression of claudin-1, occludin, ZO-1 and MUC2. Furthermore, the 16S rRNA sequencing of fecal samples was performed, and gene count and α-diversity analysis revealed that SCTPs could improve the microbial community richness. In particular, SCTPs could increase the relative abundance of Lactobacillus, Bacteroides and Akkermansia and reduce the relative abundance of Lachnospiraceae_NK4A136_group and Rikenellaceae_RC9_gut_group. These results demonstrate that SCPII possesses potential immunoregulatory activities in cyclophosphamide-induced mice by regulating intestinal microbiota diversity and improving immune organs, enhancing the proliferation ability of macrophages and splenocyte proliferation, and enhancing intestinal physical barrier function, which might provide important evidence for the development and utilization of the viscera of sea cucumber.

Two Novel Polysaccharides From Clitocybe squamulosa: Their Isolation, Structures, and Bioactivities

The crude polysaccharides from the fruiting bodies of Clitocybe squamulosa (CSFP) were isolated by hot-water extraction. Two novel polysaccharides, CSFP1-β and CSFP2-α, were further purified by DEAE-52 anion exchange and Sephacryl S-400 gel filtration chromatography, and the purities reached 98.44 and 97.83%, respectively. The structural characteristics and bioactivities of CSFP, CSFP1-β, and CSFP2-α were identified by the combination of chemical and instrumental analysis. Results showed that CSFP was formed by the aggregation of honeycomb spherical materials; CSFP1-β and CSFP2-α were interwoven by reticular and fibrous structures, respectively. Purified components of both CSFP1-β and CSFP2-α showed typical infrared absorption peaks of polysaccharides, and contents of nucleic acid and protein decreased significantly. Simultaneously, CSFP with a molecular weight (Mw) of 1.948 × 10⁴ Da were composed mainly of glucose, mannose, galactose, and rhamnose. CSFP1-β was composed mainly of glucose, galactose, and mannose, while CSFP2-α was composed of glucose, and both their Mw distributions were uneven. Compared with CSFP, the antioxidant activities of CSFP1-β and CSFP2-α were significantly improved (p < 0.05), and they both showed good abilities to bind free cholesterol and bile acid salts in vitro. The binding abilities of the two compounds were found to be 68.62 and 64.43%, and 46.66 and 45.05 mg/g, respectively. CSFP, CSFP1-β, and CSFP2-α had good bacteriostatic effects with a linear increasing relationship to increasing concentration. In addition, CSFP promoted the growth of RAW264.7 cells and has potential immunomodulatory, anti-inflammatory, and anti-tumor activities.

Purification, structural characterization, and anticoagulant activity evaluation of chondroitin sulfate from codfish (Gadus macrocephalus) bones

Chondroitin sulfate (CCS) was purified from discarded codfish (Gadus macrocephalus) bones, and its chemical structure and anticoagulant activity were assessed. CCS was obtained via enzymatic lysis and ion-exchange column chromatography, with a yield of approximately 0.15%. High-performance gel performance chromatography revealed CCS to be a largely homogeneous polysaccharide with a relatively low molecular weight of 12.3 kDa. FT-IR spectroscopy, NMR spectroscopy, and SAX-HPLC indicated that CCS was composed of monosulfated disaccharides (ΔDi4S 73.85% and ΔDi6S 19.06%) and nonsulfated disaccharides (ΔDi0S 7.09%). In vitro anticoagulation analyses revealed that CCS was able to significantly prolong activated partial thromboplastin time (APTT) and thrombin time (TT) (p < 0.05). At a CCS concentration of 5 μg/mL and 25 μg/mL, APTT and TT were approximately 1.08 and 1.12 times higher, respectively, compared to the negative control group. The results indicated that CCS might offer value as a dietary fiber supplement with the potential to prevent the incidence of coagulation-related thrombosis.

Physicochemical Characterization and Antioxidant and Hypolipidaemic Activities of a Polysaccharide From the Fruit of Kadsura coccinea (Lem.) A. C. Smith

Kadsura coccinea fruit, a novel fruit resource, has attracted wide interest, but the physicochemical characteristics and biological activities of its polysaccharides remain unclear. This study investigated the physicochemical properties of a polysaccharide extracted from K. coccinea fruit polysaccharide (KCFP) and evaluated its antioxidant and hypolipidaemic activities in vitro and in vivo. KCFP is an amorphous, thermally stable pectin heteropolysaccharide with an average molecular weight of 204.6 kDa that is mainly composed of mannose, rhamnose, glucose, galactose, xylose, arabinose, galacturonic acid (molar percentage >70%) and glucuronic acid. 2,2-Diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) free radical scavenging assays and an iron reducing antioxidant power assay showed that KCFP has strong antioxidant capacity, while the bile acid binding assay showed that KCFP has hypolipidaemic potential in vitro. The antioxidant and hypolipidaemic activities of KCFP were further evaluated in high-fat diet-induced hyperlipidaemic mice. KCFP significantly increased the activities of superoxide dismutase, glutathione peroxidase and catalase, decreased the malondialdehyde content, significantly reduced the total cholesterol (TC), triglyceride (TG) and low-density lipoprotein cholesterol (LDL-C) levels, and increased the amount of high-density lipoprotein cholesterol (HDL-C). These findings suggest that KCFP could be used as a functional food to remedy oxidative damage and hyperlipidaemia.

Structural Characterization and Immunoenhancing Effects of a Polysaccharide from the Soft Coral Lobophytum sarcophytoides

Previous studies on the soft coral Lobophytum sarcophytoides (Lobophytum sp.) are mainly about small molecules, and there has been no systematic research on polysaccharides. In the study, a novel polysaccharide (LCPs-1-A) with immunoenhancing functions was successfully extracted and purified from the soft coral Lobophytum sp. After preliminary analysis, our data indicated that LCPs-1-A was composed of glucose and had a molecular weight of 4.90 × 10⁶ Da. Moreover, our findings showed that LCPs-1-A could promote the proliferation and phagocytosis of RAW264.7 cells, stimulate the production of NO and ROS, and increase the mRNA expression of IL-1β, IL-6, and TNF-α, which indicated that LCPs-1-A had a good immunoenhancing activity. Through further studies, we found that LCPs-1-A might play an immunoenhancing role through the TLR4/NF-κB signaling pathway. Therefore, our results demonstrated that LCPs-1-A might be a natural immunostimulant for use in medical and food industries.

Ultrasound assisted aqueous two-phase extraction of polysaccharides from Cornus officinalis fruit: Modeling, optimization, purification, and characterization

Ultrasound assisted aqueous two-phase extraction of polysaccharides from Cornus officinalis fruit was modeled by response surface methodology (RSM) and artificial neural network (ANN), and optimized using genetic algorithm coupled with ANN (GA-ANN). Statistical analysis showed that the models obtained by RSM and ANN could accurately predict the Cornus officinalis polysaccharides (COPs) yield. However, ANN prediction was more accurate than RSM. The optimum extraction parameters to achieve the highest COPs yield (7.85 ± 0.09)% was obtained at the ultrasound power of 350 W, extraction temperature of 51 ℃, liquid-to-solid ratio of 17 mL/g, and extraction time of 38 min. Subsequently, the crude COPs were further purified via DEAE-52 and Sephadex G-100 chromatography to obtain a homogenous fraction (COPs-4-SG, 33.64 kDa) that contained galacturonic acid, arabinose, mannose, glucose, and galactose in a molar ratio of 34.82:14.19:6.75:13.48:12.26. The structure of COPs-4-SG was also characterized with UV-vis, fourier-transform infrared spectroscopy (FT-IR), atomic force microscopy (AFM), scanning electron microscopy (SEM), Congo-red test, and circular dichroism (CD). The findings provide a feasible way for the extraction, purification, and optimization of polysaccharides from plant resources.

Structure–immunomodulatory activity relationships of dietary polysaccharides

Polysaccharides are usually composed of more than ten monosaccharide units, which are connected by linear or branched glycosidic bonds. The immunomodulatory effect of natural polysaccharides is one of the most important bioactive function. In this review, molecular weight, monosaccharide (including galactose, mannose, rhamnogalacturonan-I arabinogalactan and uronic acid), functional groups (namely sulfate, selenium, and acetyl groups), types of glycoside bond connection (including β-1,3-D-glucosyl, α-1,4-D-glucosyl, β-1,4-D-glucosyl, α-1,6-D-glucosyl, β-1,4-D-mannosyl, and β-1,4-D-Xylopyranosyl), conformation and the branching degrees are systematically identified as their contribution to the immunostimulatory activity of polysaccharides. At present, studies on the structure-activity relationships of polysaccharides are limited due to their low purity and high heterogeneity. However, it is an important step in providing useful guidance for dietary supplements with polysaccharides. The chemical structures and the process of immune responses induced are necessary to be discussed. Polysaccharides may bind with the cell surface receptors to modulate immune responses. This review mainly discusses the structure-activity relationship of dietary polysaccharides.

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Structure - activity relationships of polysaccharides with immune-enhancing effect are proposed.

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Polysaccharides with the higher molecular weight are helpful to improve immunity.

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Higer galactose, mannose, rhamnogalacturonan-I, arabinogalacta,n and uronic acid contents have immunoregulation.

Physicochemical properties, structural characterization and biological activities of polysaccharides from quinoa (Chenopodium quinoa Willd.) seeds

In this paper, membrane separation technology was employed to separate polysaccharide fractions from the water extract of quinoa seeds. The chemical composition, structure characteristic and morphology were analyzed by chemical methods and instrumental analysis including HPLC-DAD, UV, FT-IR, Congo red test, SEM, AFM, XRD, TGA and NMR. Results indicated that three polysaccharide fractions named as QPs-I, QPs-II and QPs-III were successfully separated using microfiltration and ultrafiltration membrane with MWCO of 300 and 10 kDa in sequence. The Mw and polysaccharide content of three fractions were QPs-I (4609 Da, 33.75%), QPs-II (15,932 Da, 45.31%) and QPs-III (960,895 Da, 34.65%), respectively. The polysaccharide in three fractions was heteropolysaccharide that mainly consisted of glucose, galactose and arabinose, with their combined monosaccharide percentage being 91.17% in QPs-I, 87.81% in QPs-II, and 91.72% in QPs-III, respectively. All three polysaccharide fractions contained triple-helix structure. Biological experiment showed that antioxidant and antidiabetic activities in dose-dependent manners and also revealed immunoregulatory activity on RAW264.7 cells. These results indicated that QPs has the potential to be used in a natural agent in antioxidant, antidiabetic and immunoregulation functional food.

Structure characteristics and function of a novel extracellular polysaccharide from Bacillus thuringiensis strain 4D19

Bacillus thuringiensis (Bt) are entomopathogenic bacteria that produce different kinds of insecticidal proteins. However, studies on Bt exopolysaccharides are lacking. Here, we aimed to explore the characteristics and insecticidal synergism of EPS, an exopolysaccharide from Bt strain 4D19. The molecular weight of EPS-2 was 58.0 kDa, which consisted of mannose (44.2%), GlcN (35.5%), D-GalN (8.0%), glucose (5.5%), arabinose (5.1%), galactose (0.9%), Man-UA (0.3%) and Glc-UA (0.2%). The toxicity of insecticidal proteins against Plutella xylostella was increased by adding EPS. EPS-2 bound to Cry1Ac protoxin and promoted the binding of Cry1Ac protoxin to the gut membrane of P. xylostella, but did not bind to activated toxins. These results suggested that EPS-2 may bind to the protoxin C-terminal region to enhance insecticidal activity. Our findings indicated that Bt strains produce exopolysaccharide to enhance the toxicity of insecticidal crystal proteins, which could be applied in biopesticide research and product development.

The chemical structure and immunomodulatory activity of an exopolysaccharide produced by Morchella esculenta under submerged fermentation

The extracellular polysaccharide of Morchella esculenta cultivated under submerged fermentation was extracted. A single polysaccharide was purified through DEAE-Cellulose 52 and Sephadex G 100, and named as MEP 2a. The molecular weight of MEP 2a was determined by HPGPC and it is about 1391.5 kDa. MEP 2a is composed of mannose and glucose as the monosaccharide unit with a molar ratio of 8.15 : 1.07. The main polysaccharide chemical structure was analyzed by 1D and 2D NMR. Methylation and NMR analysis revealed that the backbone of MEP 2a consists of 1,3,4-linked-Manp, 1,2-linked-Manp and 1,6-linked-Glcp. 1D and 2D NMR results indicated that the main chain is based on →1)-β-D-Glcp-(6→, →1)-α-D-Manp-(3,4→, →1)-α-D-Manp-(2→) and the branch chain is composed of α-D-Manp-(1→, →1)-β-D-Glcp-(6→ and α-D-Glcp-(1→). MEP 2a promoted the phagocytosis function and secretion of NO, IL-1β, IL-6 and TNF-α of macrophages. In the present study, the chemical structure and immunomodulatory ability of an extracellular polysaccharide of Morchella esculenta was investigated which guarantees further research studies and promising applications.

Macromolecular and thermokinetic properties of a galactomannan from Sophora alopecuroides L. seeds: A study of molecular aggregation

The molecular aggregation of a galactomannan (NSAP-25) from Sophora alopecuroides L. seeds was investigated, where three polydisperse systems were confirmed during particle size analysis, indicating existence of different aggregates composed of random coil chains revealed by circular dichroism. Morphologically, NSAP-25 aggregate of various sizes (200-1200 nm) was possibly multi-stranded and formed by ellipsoid-like particles (20-60 nm) composed of compact coil chain, exhibiting extended amorphous structure with chain-like branches intertwined. Hence, NSAP-25 aggregation was inevitable, which exerted an unignorable effect on augmenting flexibility (β↓, γ↓, α↓ and L_p/M_L↓) and compactness (ρ↓, d_f↑ and C_∞↓) of branched random coil chain based on macromolecular analysis, especially when concentration increased. Moreover, it could be relevant to thermokinetic behavior of random nucleation and subsequent growth (A² model and negative ΔS*) as well as good thermal stability (IPDT, ITS, t_0.05, T_m and T_p), thus conferring potential applications for NSAP-25 in food and pharmaceutical industries.

Immunomodulatory effects of four polysaccharides purified from Erythronium sibiricum bulb on macrophages

Four neutral polysaccharides (ESBP1-1, ESBP1-2, ESBP2-1 and ESBP3-1) were successfully purified from the water extracted crude polysaccharides of Erythronium sibiricum bulbs through the combination of DEAE Sepharose CL-6B and Sephadex G-100 chromatography; their average molecular weights were 1.3 × 10⁴, 1.7 × 10⁴, 9.4 × 10⁵ and 4.1 × 10⁵ Da, respectively. Monosaccharide component analysis indicated that ESBP1-1 and ESBP1-2 were mainly composed of glucose (Glc). ESBP2-1 was composed of Glc, galactose (Gal) and arabinose, with a molar ratio of 24.3:1.1:1, whereas ESBP3-1 comprised Glc and Gal at a molar ratio of 14.8:1. In-vitro study showed that all of the four polysaccharides were able to considerably promote the proliferation and neutral red phagocytosis of RAW 264.7 macrophage cell. They could also stimulate the production of the cell lines' secretory molecules [nitric oxide, tumour necrosis factor-α (TNF-α) and interleukin-1β (IL-1β)] in a dose-dependent manner. However, ESBP1-2 was not included in IL-1β. Overall, these results suggested that polysaccharides from E. sibiricum bulbs can be developed as immunomodulatory ingredients for complementary medicines or functional foods. However, further animal or clinical studies are required.

Purification, structure and conformation characterization of a novel glucogalactan from Anoectochilus roxburghii

Anoectochilus roxburghii (AR) has been used in food, medicine and ornamental industries for a long time. Anion exchange resin was proposed to purify the sub-fraction of water-extracted AR polysaccharide (ARPP-70), and a homogeneous polysaccharide ARPP-70a was obtained. The structural features of ARPP-70a were characterized using gas chromatography-mass spectrometry (GC-MS), nuclear magnetic resonance (NMR) spectroscopy, and high performance size exclusion chromatograph coupled with multi-angle laser light scattering (HPSEC-MALLS). The relative weight average molecular weight for ARPP-70a was determined to be 14.8 kDa, and the molar ratio of glucose to galactose was 1.0:3.2. The structure of ARPP-70a was elucidated to be glucogalactan, with backbone comprising β-1,4-linked Galp and some α-1,4-linked Glcp. The conformation characteristics of ARPP-70a were supposed to exist as a random coil chain in 0.1 M NaNO₃ solution. Moreover, in vitro antioxidant activity assays revealed ARPP-70a exhibited appreciable antioxidant potential. To the best of our knowledge, this is the first study to obtain this type of glucogalactan, and provide systematic information on its structural and conformational properties. This study improved the understanding of the physicochemical characteristics of AR polysaccharide, which is beneficial for its further application in food and medicinal industry.

Structural properties and in vitro and in vivo immunomodulatory activity of an arabinofuranan from the fruits of Akebia quinata

In our continuous searching for natural active polysaccharides with immunomodulatory activity, an arabinofuranan (AQP70-3) was isolated and purified from the fruits of Akebia quinata (Houtt.) Decne. by using ion-exchange chromatography and gel permeation chromatography for the first time. AQP70-3 contained both α-l-Araf and β-l-Araf, and the absolute molecular weight was 1.06 × 10⁴ g/mol. The backbone of AQP70-3 comprised →5)-α-l-Araf-(1→, →3,5)-α-l-Araf-(1→, and →2,5)-α-l-Araf-(1→, with branches of →1)-β-l-Arafand →3)-α-l-Araf-(1→ residues. Biological assay suggested that AQP70-3 can stimulate phagocytic activity and promote the levels of nitric oxide (NO), interleukin (IL)-6, IL-1β, and tumor necrosis factor-α (TNF-α) of RAW264.7 cells. Furthermore, AQP70-3 was found to increase the production of reactive oxygen species (ROS) and NO in zebrafish embryo model.

Comparative study on the bioactive components and in vitro biological activities of three green seedlings

To explore functional food ingredients from green seedlings, the bioactive components (phenolic compounds and γ-aminobutyric acid) and antioxidant activities (DPPH radical scavenging ability, ABTS radical scavenging ability and reducing power) of three green seedlings, including coix seed seedling (CSS), highland barely seedling (HBS) and naked oats seedling (NOS) cultivars were respectively measured and deeply compared. Results indicated that CSS showed the highest contents of the total polyphenol (183.35 mg/100 g), total flavonoid (348.68 mg/100 g), and γ-aminobutyric acid (54.17 mg/100 g). As expected, CSS also exerted the highest level of antioxidant activity, followed by HBS and NOS. Moreover, CSS possessed the potential of stimulating immune responses, including promoting proliferation and strengthening phagocytosis function of RAW264.7 cells. Taken together, all results suggested that the three green seedlings, especially CSS could be used as natural ingredients for functional food.

Structure and immunostimulating activity of a galactofuranose-rich polysaccharide from the bamboo parasite medicinal fungus Shiraia bambusicola

ETHNOPHARMACOLOGICAL RELEVANCE

Shiraia bambusicola is a parasitic fungus on the twigs of bamboos. Its relatively large stroma has high medicinal value and can treat a variety of diseases such as rheumatoid arthritis, cold stomach pain, sciatica, injuries, chronic bronchitis, and infantile. It is widely distributed in many provinces in Southern China and also is also found in Japan.

AIM OF THE STUDY

Medicinal fungi were important resources for bioactive polysaccharides. To explore bioactive polysaccharides from Shiraia bambusicola, a heteropolysaccharide SB2-1 was purified and obtained from S. bambusicola and its immunostimulating activity was researched.

MATERIALS AND METHODS

The polysaccharide from S. bambusicola was extracted and purified using enzyme assisted extraction, ethanol precipitation, anion-exchange and size-exclusion chromatography. Molecular weight of polysaccharide was estimated by high performance gel permeation chromatography. Monosaccharide compositions were determined by high performance liquid chromatography after pre-column derivatization and UV detection. Structure information was elucidated by IR spectrum, GC-MS analysis after methylation and gradual acid hydrolysis of the polysaccharide. The RAW264.7 cells were used to study the immunostimulating activity in vitro.

RESULTS

Physicochemical and structural analyses showed that SB2-1 was a neutral heteropolysaccharide with molecular weight at 22.2 kDa and consisted of glucose, galactose and mannose at a ratio of 2.0:1.5:1.0. The structure of SB2-1 was a branched polysaccharides composed of a mannan core and side chains consisted of glucose and galactose. The mannan core was composed of (1→2)-Manp as the main chain. Glucose with (1→4)-D-Glcp, (1→2)-D-Glcp and (1→6)-D-Glcp at different degrees of polymerization were linked at C-6 and C-3 of the (1→2)-Manp as the side chains. The galactose with the linages of (1→6)-D-Galf, →2)-D-Galf(1→ and terminal D-Galf(1→ also existed in the side chain. The study on the immunostimulating activities of SB2-1 and its core structure P-2 were investigated on RAW264.7 macrophages. The results showed that SB2-1 could activate RAW264.7 macrophage and significantly improve its phagocytic ability by neutral red uptake experiment. Meanwhile, SB2-1 increased significantly higher inducible nitric oxide synthase (iNOS) production and the productions of IL-1, IL-6, IL-12 and TNF-α. The effect of SB2-1 was better than its core structure P-2 produced by gradual acid hydrolysis, which meant the side chains played an important role in the immunostimulating activities.

CONCLUSIONS

The investigation demonstrated that the galactofuranose-containing mannogalactoglucan was characteristic polysaccharides in S. bambusicola and could enhance the activation of macrophages.

Extraction, structural characterization, and immunobiological activity of ABP Ia polysaccharide from Agaricus bisporus

The extraction, purification, immunobiological activities, and structure of Agaricus bisporus polysaccharides (ABP) were investigated. Especially we purified and identified the polysaccharides with the highest in vitro immunobiological activity. The extraction conditions of ABP were optimized using single factor and orthogonal experiment. ABP Ia was screened after double purification with DEAE-52 and Sephadex G-200 and showed the best immunoregulatory activity. UV spectra analysis and high-performance gel permeation chromatography results indicated that the ABP Ia fraction did not contain any proteins or nucleotides and was a homogeneous polysaccharide with a relative molecular weight of 784 kDa. Gas chromatography mass spectroscopy results showed that ABP Ia was a heteropolysaccharide consisting of ribose, rhamnose, arabinose, xylose, mannose, glucose, and galactose at a molar ratio of 2.08:4.61:2.45:22.25:36.45:89.22:1.55. FT-IR and periodic acid oxidation analysis indicated that ABP Ia was an α-pyran polysaccharide composed of 1 → 2 and 1 → 4 glycosidic bonds, as well as a possible 1 → 3 glycosidic bond. Furthermore, atomic force microscopy revealed that ABP Ia polysaccharide chains twisted to form a rod-like architecture and, at a 5% concentration, aggregated into a tight structure similar to the shape of a stone forest. These findings identify ABP Ia as a potential functional food ingredient or pharmaceutical for immunoregulation.

Isolation, structural elucidation, and immunoregulation properties of an arabinofuranan from the rinds of Garcinia mangostana

In our search for bioactive polysaccharides as immunomodulatory agents, an arabinofuranan (GMP90-1) was purified and characterized from the rinds of Garcinia mangostana L. GMP90-1 (absolute molecular weight: 5.30 × 10³ g/mol) was found to be composed of arabinose, galactose, and rhamnose. The backbone of GMP90-1 was determined as (1→5)-linked α-l-Araf, (1→2,3,5)-linked α-l-Araf, (1→3,5)-linked α-l-Araf, (1→6)-linked β-d-Galp, and (1→2)-linked α-l-Rhap. Conformational analysis revealed GMP90-1 to exist as a rigid rod structure in sodium chloride solution. To explore its potential as immunomodulatory agents, an in vitro cell screening was performed and GMP90-1 was found to significantly enhance the phagocytic uptake of neutral red and improve the secreted level of nitric oxide (NO), interleukin (IL)-6, IL-1β, and tumor necrosis factor-α (TNF-α) of macrophages. Furthermore, the cellular immunomodulatory activities were confirmed by the in vivo zebrafish experiment, which suggested that GMP90-1 with immunomodulatory effects could be considered as a potential immunomodulatory for immune diseases.