Use of statistical methods to find the polysaccharide structural characteristics and the relationships between monosaccharide composition ratio and macrophage stimulatory activity of regionally different strains of Lentinula edodes

Purification, structural characterization and immunomodulatory activity of a polysaccharide isolated from Scutellaria baicalensis stem-leaf

In our research, a novel polysaccharide (named SSP-3a) with uniform molecular weight was extracted from Scutellaria baicalensis stem-leaf. The structural analysis revealed that SSP-3a was an acidic polysaccharide with a heavy average molecular weight of 1.83 × 105 Da. By HPLC, the primary constituents of SSP-3a were mannose (11.60 %), glucuronic acid (42.99 %), glucose (23.43 %), and xylose (22.04 %). According to FT-IR and 1H NMR analysis, it was confirmed to be a β-configuration pyranose with a CO stretching vibrational peak. The immunomodulation results also showed that SSP-3a not only significantly promoted RAW264.7 cell proliferation and phagocytosis, but also stimulated the release of NO and cytokines. Furthermore, mechanistic studies suggested that SSP-3a had the ability to trigger MAPKs and NF-κB immunological signaling pathways via TLR4 receptors. The findings suggested that SSP-3a might be a beneficial active component for the food and pharmaceutical industries.

Ultrasonic-assisted extraction of a low molecular weight polysaccharide from Nostoc commune Vaucher and its structural characterization and immunomodulatory activity

In the current study, a novel crude polysaccharide (cNCEP) was extracted from N. commune Vaucher utilizing ultrasonic-assisted extraction (UAE) with 60 % ethanol, employing response surface methodology. The optimal yield of cNCEP was determined to be 8.07 ± 0.08 mg/g, achieved through ultrasonic-assisted extraction under the conditions of a material-to-liquid ratio of 1:22, temperature of 56 °C, power of 570 W, and duration of 147 min. Subsequent purification of NCEP via Sephadex G75 resulted in a novel polysaccharide with a molecular weight of 20.466 kDa. NCEP exhibited significant scavenging activites against DPPH and hydroxyl radicals, as well as notable in vitro immunomodulatory properties. Furthermore, the mechanisms underlying the immunomodulatory effects of NCEP, involving enhancement of immunity, were investigated, revealing potential regulation of MAPK and TLR4-IRF7-NF-κB signaling pathways through RNA-Seq and Western blot analyses. These findings highlight the promising potential of NCEP as an organic immunomodulatory agent and functional food ingredient.

Monosaccharide composition analysis by 2D quantitative gsHSQCi

The physicochemical properties and biological activities of polysaccharides depend on their structures. Monosaccharide composition analysis is indispensable for the structural characterization of polysaccharides and is helpful in the quality control of polysaccharide preparation. Here, using a model mixture and tamarind seed polysaccharide as examples, we demonstrated that a quantitative 2D NMR method, gsHSQCi (three gradient-selective Heteronuclear Single Quantum Coherence spectra acquired with incremented repetition times, i = 1, 2, 3) can directly quantify a variety of monosaccharides in solution with adequate precision and accuracy, requiring no derivatization, postprocessing steps and column separation. Both anomeric and non-anomeric signals of monosaccharides can be utilized for content determination. More accurate quantification of fructose in a mixture containing nine monosaccharides is obtained, which is difficult to achieve by quantitative 1D 1HNMR and the common PMP-HPLC method (high-performance liquid chromatography through pre-column derivatization with 1-phenyl-3-methyl-5-pyrazolone) due to the peak overlapping and the poor derivatization efficiency, respectively. The results also revealed that Na[Fe(EDTA)] can serve as a proper relaxation-enhancing agent for saccharide samples to save experimental time. We expect that this approach can be applied as an alternative to analyzing the monosaccharide composition and be helpful in interpreting the structure of polysaccharides.

Fucoidan from the cell wall of Silvetia siliquosa with immunomodulatory effect on RAW 264.7 cells

Silvetia siliquosa, the only species of the family Fucaceae in China, is used as a medicine food homology. Fucoidan from S. siliquosa was extracted by hot water twice thoroughly (13 % of total yield), and a purified fucoidan SSF with a molecular weight of 93 kD was obtained. Chemical composition analysis demonstrated that SSF was primarily composed of sulfate (21.68 wt%) and fucose (84 % of all neutral monosaccharides). IR, methylation analysis, NMR and ESI-MS results indicated SSF had the backbone of mainly (1 → 3)-α-L-fucopyranose and minor (1 → 4)-α-L-fucopyranose, with little 1,3 and 1,4 branched β-D-Xylp and β-D-Galp. The in vitro immunomodulatory test on RAW 264.7 cells showed that SSF could up-regulate the expression of immune related factors and proteins in a concentration-dependent manner, but the immunomodulatory effect disappeared from desulfated SSF. This research indicated that highly sulfated fucan possessed immunomodulatory effect and the importance of sulfate groups in the activity of SSF.

Analyzing the structure-activity relationship of raspberry polysaccharides using interpretable artificial neural network model

The structure-activity relationship has been a hot topic in the field of polysaccharide research. Six polysaccharides and three polysaccharide fragments were obtained from raspberry pulp. Based on their structural information and immune-enhancing activity data, an artificial neural network (ANN) model was used for prediction, and Gradient-weighted class activation mapping (Grad-CAM) algorithm was exploited for explanation structure-activity relationship of these raspberry polysaccharides in the present study. The structural information and immune activity data of raspberry polysaccharides were respectively used as input and output in the ANN model. The training and testing losses of ANN model was no longer decreased after trained for 200 epochs. The mean-square error (MSE) of training set and test set stabilized around 0.003 and 0.013, and the mean absolute percentage error (MAPE) of training set and test set were 0.21 % and 0.98 %, indicating the trained ANN model converged well and exhibited strong robustness. The interpretability analysis showed that molecular weight, content of arabinose, galactose or galacturonic acid, and glycosyl linkage patterns of →3)-Arap-(1→, Araf-(1→, →4)-Galp-(1 → were the main structural factors greatly affecting the immune-enhancing activity of raspberry polysaccharides. This work may provide a new perspective for the study of structure-activity relationship of polysaccharides.

Structural characterization of a glycoprotein from white jade snails (Achatina Fulica) and its wound healing activity

Snail mucus is rich in proteins and polysaccharides, which has been proved to promote wound healing in mice in our previous research. The aim of this study was to investigate the effective component in snail mucus that can exert the wound healing potential and its structural characterization. Here, the glycoprotein from the snail mucus (SM1S) was obtained by DEAE-Sepharose Fast Flow and Sephacryl S-300 columns. The structural characteristics of SM1S were investigated via chromatographic techniques, periodic acid oxidation, FT-IR spectroscopy and NMR spectroscopy. Results showed that SM1S was a glycoprotein with a molecular weight of 3.8 kDa (83.23 %), consists of mannose, glucuronic acid, glucose, galactose, xylose, arabinose, fucose at a ratio of 13.180:4.875:1043.173:7.552:1:3.501:2.058. In addition, the periodic acid oxidation and NMR analysis showed that SM1S contained 1,6-glycosidic bonds, and might also contain 1 → 4 and 1 → 2 glycosidic or 1 → 3 glycosidic bonds. Furthermore, the migration experiment of human skin fibroblasts in vitro suggested that SM1S had a good effect to accelerate the scratch healing of cells. This study suggested that SM1S may be a prospective candidate as a natural wound dressing for the development of snail mucus products.

The isolation, characterization and biological activities of the non-glucan polysaccharides from the high-starch-content plant Pueraria mirifica

The dried root of Pueraria mirifica (P. mirifica) is an edible foodstuff widely used in Asian countries. P. mirifica is known for its high starch content. The isolation of polysaccharides from high-starch plant parts is challenging due to the interference of starch. Therefore, this study aimed to develop a technique for isolating and investigating the structure and activity of non-glucan polysaccharides from P. mirifica (PMP). An effective starch removal process was developed using α-amylase hydrolysis and thorough membrane dialysis. Four non-glucan polysaccharides were isolated, and PMP-2 was subjected to structural elucidation. The results indicated that PMP-2 has a molecular weight of 124.4 kDa and that arabinose and galactose are the main components, accounting for 27.8 % and 58.5 %, respectively. Methylation and NMR analysis suggested that PMP-2 is an Arabinogalactan composed of 1,6-linked Galp and 1,4-linked Galp as the main chain, with arabinan and rhamnose as side chains. Furthermore, PMP-C and PMP-2 exhibited concentration-dependent antioxidant activities against DPPH, ABTS, and hydroxyl radicals and certain immunomodulatory activities related to the release of NO, TNF-α and IL-6. These findings suggest that PMP-2 has potential therapeutically active ingredient in functional foods. The developed method successfully removed starch and isolated non-glucan polysaccharides from the high-starch content plant P. mirifica and can be applied to other high-starch plants.

A newly discovered glycosyltransferase gene UGT88A1 affects growth and polysaccharide synthesis of Grifola frondosa

Grifola frodosa polysaccharides, especially β-D-glucans, possess significant anti-tumor, antioxidant and immunostimulatory activities. However, the synthesis mechanism remains to be elucidated. A newly discovered glycosyltransferase UGT88A1 was found to extend glucan chains in vitro. However, the role of UGT88A1 in the growth and polysaccharide synthesis of G. frondosa in vivo remains unclear. In this study, the overexpression of UGT88A1 improved mycelial growth, increased polysaccharide production, and decreased cell wall pressure sensitivity. Biomass and polysaccharide production decreased in the silenced strain, and the pressure sensitivity of the cell wall increased. Overexpression and silencing of UGT88A1 both affected the monosaccharide composition and surface morphology of G. frondosa polysaccharides and influenced the antioxidant activity of polysaccharides from different strains. The messenger RNA expression of glucan synthase (GLS), UTP-glucose-1-phosphate uridylyltransferase (UGP), and UDP-xylose-4-epimerase (UXE) related to polysaccharide synthesis, and genes related to cell wall integrity increased in the overexpression strain. Overall, our study indicates that UGT88A1 plays an important role in the growth, stress, and polysaccharide synthesis of G. frondosa, providing a reference for exploring the pathway of polysaccharide synthesis and metabolic regulation. KEY POINTS: •UGT88A1 plays an important role in the growth, stress response, and polysaccharide synthesis in G. frondosa. •UGT88A1 affected the monosaccharide composition, surface morphology and antioxidant activity of G. frondosa polysaccharides. •UGT88A1 regulated the mRNA expression of genes related to polysaccharide synthesis and cell wall integrity.

Effect of monosaccharide composition and proportion on the bioactivity of polysaccharides: A review

Polysaccharides have been widely used in pharmaceutical and food industries due to their diverse bioactivity, high safety, and few or no side effects. However, inability to quickly produce, screen, and synthesize bioactive polysaccharides is the limiting factor for their development and application. Structural features determine and influence the bioactivity of polysaccharides. Among them, monosaccharide is the basic unit of polysaccharide, which not only affects electrification, functional group, and bioactivity of polysaccharide but also is one of the simplest polysaccharide indexes to be detected. At present, effects of monosaccharide composition and proportion on anti-inflammatory, antioxidant, antitumor, immunomodulatory, antibacterial, and prebiotic activities of polysaccharides are reviewed. Further problems need to be considered during regulation and analysis of monosaccharide composition and proportion of polysaccharides. Overall, present work will provide help and reference for production, development, and structure-function investigation of polysaccharides based on their monosaccharide.

Antitumor effects of polysaccharides from medicinal lower plants: A review

Cancer is one of the leading causes of death worldwide, yet the drugs currently approved for cancer treatment are associated with significant side effects, making it urgent to develop alternative drugs with low side effects. Polysaccharides are natural polymers with ketone or aldehyde groups, which are widely found in plants and have various biological activities such as immunomodulation, antitumor and hypolipidemic. The lower plants have attracted much attention for their outstanding anticancer effects, and many studies have shown that medicinal lower plant polysaccharides (MLPPs) have antitumor activity against various cancers and are promising alternatives with potential development in the food and pharmaceutical fields. Therefore, this review describes the structure and mechanism of action of MLPPs with antitumor activity. In addition, the application of MLPPs in cancer treatment is discussed, and the future development of MLPPs is explored.

Mycelial biomass and intracellular polysaccharides production, characterization, and activities in Auricularia auricula-judae cultured with different carbon sources

The carbon source, an essential factor for submerged culture, affects fungal polysaccharides production, structures, and activities. This study investigated the impact of carbon sources, including glucose, fructose, sucrose, and mannose, on mycelial biomass and the production, structural characterization, and bioactivities of intracellular polysaccharides (IPS) produced by submerged culture of Auricularia auricula-judae. Results showed that mycelial biomass and IPS production varied with different carbon sources, where using glucose as the carbon source produced the highest mycelial biomass (17.22 ± 0.29 g/L) and IPS (1.62 ± 0.04 g/L). Additionally, carbon sources were found to affect the molecular weight (Mw) distributions, monosaccharide compositions, structural characterization, and activities of IPSs. IPS produced with glucose as the carbon source exhibited the best in vitro antioxidant activities and had the strongest protection against alloxan-damaged islet cells. Correlation analysis revealed that Mw correlated positively with mycelial biomass (r = 0.97) and IPS yield (r = 1.00), while IPS antioxidant activities correlated positively with Mw and negatively with mannose content; the protective activity of IPS was positively related to its reducing power. These findings indicate a critical structure-function relationship for IPS and lay the foundation for utilizing liquid-fermented A. aruicula-judae mycelia and the IPS in functional food production.

Structural Characterization and In Vitro Antioxidant, Hypoglycemic and Hypolipemic Activities of a Natural Polysaccharide from Liupao Tea

This study extracted and purified a natural polysaccharide (TPS-5) that has a molecular weight of 48.289 kDa from Liupao tea, a typical dark tea with many benefits to human health. TPS-5 was characterized as a pectin-type acidic polysaccharide. It has a backbone composed of → 2,4)- α- L-Rhap-(1) → 4)- α- D-GalAp-(1) →, with a branch composed of → 5)- α- L-Ara-(1 → 5,3)- α- L-Ara-(1 → 3)- β- D-Gal-(1 → 3,6)- β- D-Galp-(1) →. The in vitro biological activity evaluation illustrated that TPS-5 has free radical scavenging, ferric-ion-reducing, digestive enzyme inhibitory, and bile-salt-binding abilities. These results suggest that TPS-5 from Liupao tea has potential applications in functional foods or medicinal products.

Cordyceps militaris polysaccharide alleviates ovalbumin-induced allergic asthma through the Nrf2/HO-1 and NF-κB signaling pathways and regulates the gut microbiota

Polysaccharides, as one of the main types of bioactive components of Cordyceps militaris, have anti-allergic asthma effects. Herein, an ovalbumin-induced allergic asthma mouse model was established to assess the potential mechanisms of the separated and purified Cordyceps militaris polysaccharide (CMP). CMP is an α-pyranose with a molecular weight of 15.94 kDa that consists of Glc, Man, Gal, Xyl, Ara and GlcA in a molar ratio of 81.25:21.96:13.88:3.92:3.58:1.00. CMP improved inflammatory cytokine levels, alleviated the histopathological changes in the lung and intestinal tissues, regulated the expression of mRNA and proteins related to oxidative stress and inflammatory pathways, reversed gut dysbiosis at the phylum and family levels and improved microbiota function in allergic asthma mice. Moreover, it was found that the levels of inflammatory cytokines in lung tissue of mice were significantly correlated with some intestinal microbial communities. Overall, CMP improved oxidative stress and the inflammatory response in allergic asthma mice by regulating the Nrf2/HO-1 and NF-κB signaling pathways, which may be closely correlation with maintaining the stability of the gut microbiota.

Flash Extraction, Characterization, and Immunoenhancement Activity of Polysaccharide from Hippophae rhamnoides Linn

Hippophae rhamnoides L. polysaccharide was optimized with flash extraction by response surface design. The optimum process conditions were: rotation rate 5000 r/min, extraction time 15 s, extraction temperature 90 °C and liquid-to-material ratio 38 mL/g, the extraction yield was 15.28±0.02 %. HRP-1 and HRP-2 obtained by 40 % and 60 % graded alcohol precipitation were characterized. The results indicated that HRP-1 and HRP-2 both composed of mannose, ribose, rhamnose, glucuronic acid, galacturonic acid, glucose, galactose, xylose, arabinose with different molar ratio and the molecular weights were 380.59 kDa and 288.24 kDa, respectively. In addition, the in vitro antioxidant and immunoenhancement activities of HRP-1 and HRP-2 were analyzed, and the two fractions showed good free radical scavenging activity against ⋅OH, ABTS⋅⁺ , DPPH⋅, and extremely strong immunomodulatory activity against RAW264.7 cells. Indicating that flash extraction is suitable for extraction of HRP, the structural study of HRP provides a scientific theoretical basis for the development of Hippophae rhamnoides.

Effect of fermentation modification on the physicochemical characteristics and anti-aging related activities of Polygonatum kingianum polysaccharides

In order to fully investigate the anti-aging value of the plants polysaccharides, the fermentation method was applied to modify the Polygonatum kingianum polysaccharides (PKPS), and the ultra-filtration was used to further segment the hydrolyzed polysaccharides. It was found that the fermentation induced an increase in the in vitro anti-aging-related activities of PKPS including antioxidant, hypoglycemic and hypolipidemic activity, and cellular aging-delaying ability. In particular, the low Mw fraction PS2-4 (10-50 kDa) separated from the fermented polysaccharide exhibited superior anti-aging activity on experimental animals. PS2-4 extended the Caenorhabditis elegans lifespan by 20.70 %, with an increased effect of 10.09 % compared to the original polysaccharide; it was also more effective than the original one in improving movement ability and reducing lipofuscin accumulation of worms. This fraction was screened as the optimal anti-aging active polysaccharide. After fermentation, the main molecular weight distribution of PKPS changed from 50-650 kDa to 2-100 kDa, and the chemical composition and monosaccharide composition also changed; the initial rough and porous microtopography turned into smooth state. These alterations in physicochemical characteristics suggest that fermentation exerted an influence on the structure of PKPS, which contributed to the enhanced anti-aging activity, indicating that fermentation was promising in the structural modification of polysaccharides.

The Effect of Novel Selenopolysaccharide Isolated from Lentinula edodes Mycelium on Human T Lymphocytes Activation, Proliferation, and Cytokines Synthesis

Polysaccharides isolated from Lentinula edodes are bioactive compounds with immunomodulatory properties. In our previous studies from L. edodes mycelium, we have isolated a selenium(Se)-enriched fraction (named Se-Le-30), a mixture of linear 1,4-α-glucan and linear 1,3-β- and 1,6-β-glucans. In this study, we analyzed the effects of Se-Le-30 on the activation and proliferation of human T lymphocytes stimulated by anti-CD3 and anti-CD3/CD28 antibodies (Abs) and on the production of cytokines by peripheral blood mononuclear cells (PBMCs). Se-Le-30 had effects on T cell proliferation induced by Abs against CD3 and CD28. It significantly inhibited the proliferation of CD3-stimulated CD4⁺ and CD8⁺ T cells and enhanced the proliferation of CD4⁺ T cells stimulated with anti-CD3/CD28 Ab. Moreover, Se-Le-30 downregulated the number of CD3-stimulated CD4⁺CD69⁺ cells, CD4⁺CD25⁺ cells, as well as CD8⁺CD25⁺ cells, and upregulated the expression of CD25 marker on CD4+ and CD8+ T cells activated with anti-CD3/CD28 Abs. Furthermore, Se-Le-30 enhanced the synthesis of IFN-γ by the unstimulated and anti-CD3/CD28-stimulated PBMCs, inhibited synthesis of IL-2 and IL-4 by CD3-stimulated cells, and augmented the synthesis of IL-6 and IL-10 by unstimulated, CD3-stimulated, and CD3/CD28-stimulated PBMCs. Together, we demonstrated that Se-Le-30 exerts immunomodulatory effects on human T lymphocytes. These observations are of importance for the prospective use of Se-Le-30 in research or as a therapeutic compound.

Bioactive polysaccharides and oligosaccharides from garlic (Allium sativum L.): Production, physicochemical and biological properties, and structure-function relationships

Garlic is a common food, and many of its biological functions are attributed to its components including functional carbohydrates. Garlic polysaccharides and oligosaccharides as main components are understudied but have future value due to the growing demand for bioactive polysaccharides/oligosaccharides from natural sources. Garlic polysaccharides have molecular weights of 1 × 10³ to 2 × 10⁶  Da, containing small amounts of pectins and fructooligosaccharides and large amounts of inulin-type fructans ((2→1)-linked β-d-Fruf backbones alone or with attached (2→6)-linked β-d-Fruf branched chains). This article provides a detailed review of research progress and identifies knowledge gaps in extraction, production, composition, molecular characteristics, structural features, physicochemical properties, bioactivities, and structure-function relationships of garlic polysaccharides/oligosaccharides. Whether the extraction processes, synthesis approaches, and modification methods established for other non-garlic polysaccharides are also effective for garlic polysaccharides/oligosaccharides (to preserve their desired molecular structures and bioactivities) requires verification. The metabolic processes of ingested garlic polysaccharides/oligosaccharides (as food ingredients/dietary supplements), their modes of action in healthy humans or populations with chronic conditions, and molecular/chain organization-bioactivity relationships remain unclear. Future research directions related to garlic polysaccharides/oligosaccharides are discussed.

Effect of Platycodon grandiflorus Polysaccharide on M1 Polarization Induced by Autophagy Degradation of SOCS1/2 Proteins in 3D4/21 Cells

M1-polarized macrophages can improve the body’s immune function. This study aimed to explore the mechanism of Platycodon grandiflorus polysaccharide (PGPS_t) degrading SOCS1/2 protein through autophagy and promoting M1 polarization in 3D4/21 cells. Immunoprecipitation, confocal laser scanning microscopy, flow cytometry, and intracellular co-localization were used to detect the expression of related phenotypic proteins and cytokines in M1-polarized cells. The results showed that PGPS_t significantly promoted the mRNA expression of IL-6, IL-12, and TNF-α and enhanced the protein expression of IL-6, IL-12, TNF-α, IL-1β, iNOS, CD80, and CD86, indicating that PGPS_t promoted M1 polarization in 3D4/21 cells. Next, the effect of the PGPS_t autophagy degradation of SOCS1/2 on the M1 polarization of 3D4/21 cells was detected. The results showed that PGPS_t significantly downregulated the expression level of SOCS1/2 protein, but had no obvious effect on the mRNA expression level of SOCS1/2, indicating that PGPS_t degraded SOCS1/2 protein by activating the lysosome system. Further research found that under the action of 3-MA and BafA1, PGPS_t upregulated LC3B II and downregulated SOCS1/2 protein expression, which increased the possibility of LC3B, the key component of autophagy, bridging this connection and degrading SOCS1/2. The interaction between SOCS1/2 and LC3 was identified by indirect immunofluorescence and Co-IP. The results showed that the co-localization percentage of the two proteins increased significantly after PGPS_t treatment, and LC3 interacted with SOCS1 and SOCS2. This provides a theoretical basis for the application of PGPS_t in the treatment or improvement of diseases related to macrophage polarization by regulating the autophagy level.

The Main Structural Unit Elucidation and Immunomodulatory Activity In Vitro of a Selenium-Enriched Polysaccharide Produced by Pleurotus ostreatus

In recent years, the structure of selenium-enriched polysaccharides and their application in immunomodulation have attracted much attention. In previous studies, we extracted and purified a novel selenium-enriched Pleurotus ostreatus polysaccharide called Se-POP-21, but its structure and immunomodulatory activity were still unclear. In this study, the main structural unit formula of Se-POP-21 was characterized by methylation analysis and an NMR experiment. The results showed that the backbone of Se-POP-21 was →[2,6)-α-D-Galp-(1→6)-α-D-Galp-(1]₄→2,4)-β-L-Arap-(1→[2,6)-α-D-Galp-(1→6)-α-D-Galp-(1]₄→, branched chain of β-D-Manp-(1→ and β-D-Manp-(1→4)-β-L-Arap-(1→ connected with →2,6)-α-D-Galp-(1→ and →2,4)-β-L-Arap-(1→,respectively, through the O-2 bond. In vitro cell experiments indicated that Se-POP-21 could significantly enhance the proliferation and phagocytosis of RAW264.7 cells, upregulate the expression of costimulatory molecules CD80/CD86, and promote RAW264.7 cells to secrete NO, ROS, TNF-α, IL-1β, and IL-6 by activating the NF-κB protein. The results of this study indicate that Se-POP-21 can effectively activate RAW264.7 cells. Thus, it has the potential to be used in immunomodulatory drugs or functional foods.

Cyanobacteria Secondary Metabolites as Biotechnological Ingredients in Natural Anti-Aging Cosmetics: Potential to Overcome Hyperpigmentation, Loss of Skin Density and UV Radiation-Deleterious Effects

The loss of density and elasticity, the appearance of wrinkles and hyperpigmentation are among the first noticeable signs of skin aging. Beyond UV radiation and oxidative stress, matrix metalloproteinases (MMPs) assume a preponderant role in the process, since their deregulation results in the degradation of most extracellular matrix components. In this survey, four cyanobacteria strains were explored for their capacity to produce secondary metabolites with biotechnological potential for use in anti-aging formulations. Leptolyngbya boryana LEGE 15486 and Cephalothrix lacustris LEGE 15493 from freshwater ecosystems, and Leptolyngbya cf. ectocarpi LEGE 11479 and Nodosilinea nodulosa LEGE 06104 from marine habitats were sequentially extracted with acetone and water, and extracts were analyzed for their toxicity in cell lines with key roles in the skin context (HaCAT, 3T3L1, and hCMEC). The non-toxic extracts were chemically characterized in terms of proteins, carotenoids, phenols, and chlorophyll a, and their anti-aging potential was explored through their ability to scavenge the physiological free radical superoxide anion radical (O2•−), to reduce the activity of the MMPs elastase and hyaluronidase, to inhibit tyrosinase and thus avoid melanin production, and to block UV-B radiation (sun protection factor, SPF). Leptolyngbya species stood out for anti-aging purposes: L. boryana LEGE 15486 presented a remarkable SPF of 19 (at 200 µg/mL), being among the best species regarding O2•− scavenging, (IC50 = 99.50 µg/mL) and also being able to inhibit tyrosinase (IC25 = 784 µg/mL), proving to be promising against UV-induced skin-aging; L. ectocarpi LEGE 11479 was more efficient in inhibiting MMPs (hyaluronidase, IC50 = 863 µg/mL; elastase, IC50 = 391 µg/mL), thus being the choice to retard dermal density loss. Principal component analysis (PCA) of the data allowed the grouping of extracts into three groups, according to their chemical composition; the correlation of carotenoids and chlorophyll a with MMPs activity (p < 0.01), O2•− scavenging with phenolic compounds (p < 0.01), and phycocyanin and allophycocyanin with SPF, pointing to these compounds in particular as responsible for UV-B blockage. This original survey explores, for the first time, the biotechnological potential of these cyanobacteria strains in the field of skin aging, demonstrating the promising, innovative, and multifactorial nature of these microorganisms.

Isolation, structural characterization and bioactivities of polysaccharides from Laminaria japonica: A review

Laminaria japonica is a familiar marine plant and is often used as food due to its abundant carbohydrates, vitamins and minerals. As one of the main types of active substances in L. japonica, polysaccharides are widely used in the food and chemical industries and in medicine and healthcare due to their health benefits, such as immunoregulatory, antioxidant, and antidiabetic effects. However, there has been no systematic summary of the isolation, structural characterization and bioactivities of L. japonica polysaccharides (LJPs). Therefore, the present review includes a survey of extraction and purification methods for these bioactive molecules, along with a dissertation on the structural characterization of the carbohydrate components. Moreover, an overview of the most recent results related to LJP biological activities is provided. This review provides a useful reference for further research, production, and application of LJPs in functional foods and therapeutic agents.

Structure, immunostimulatory activity, and the effect of ameliorating airway inflammation of polysaccharides from Pyrus sinkiangensis Yu

Purified acid polysaccharides PSAP-1 and PSAP-2 with apparent molecular weights of 64.6 and 38.9 kDa, respectively, were isolated from Pyrus sinkiangensis Yu. through combined techniques of ion-exchange and gel permeation chromatography. Both polysaccharides were composed of predominant amounts of GalA and small amounts of Ara, Rha, and Gal. They are deduced to be native pectin-type polysaccharides containing the HG backbone consisting of α-1,4-GalAp and methyl-esterified α-1,4-GalAp residues by IR, GC-MS and NMR spectra analyses. The immunoregulatory activity test showed that PSAP-1 and PSAP-2 could increase the cell viability and the release of NO, IL-6, and TNF-α on the RAW264.7 macrophage. It indicated that PSAP-1 and PSAP-2 could increase macrophage-mediated immunostimulatory activity. The airway inflammation test of antiasthmatic mice showed that PSAP-1 could decrease the contents of IL-4, IL-5, and IL-13 and the number of inflammatory cells in BALF and improve the pathological changes in lung tissue. PSAP-1 could also decrease the amount of mucus secreted by goblet cells and the expression levels of NF-κB p65, IκBα, IKK, ERK, JNK, P38, and Muc5ac mRNA and increase the expression levels of TLR2 and TLR4 mRNA in lung tissues. This suggested that PSAP-1 may resist airway inflammation in mice. PSAP-1 and PSAP-2 had potential clinical application value.

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.

Extraction, structural characterization, and antioxidant and immunomodulatory activities of a polysaccharide from Notarchus leachii freeri eggs

The crude polysaccharides (NLCEP) were extracted from Notarchus leachii freeri eggs strings by the saltextractionmethod. The extraction conditions were optimized using the single-factorexperimentmethod and response surface method (RSM). The results showed that the maximum extraction yield of NLCEP was obtained under the following conditions: NaCl solution concentration of 2.96 %, raw material to liquid ratio of 1: 40 g/mL, extraction time of 2 h and extraction temperature of 69 °C. A new novel pure polysaccharide fraction named as NLCEPs-1 was fractionated from NLCEP by using DEAE-Cellulose 52 and Sephadex G-100. Its structure and immunomodulatory and antioxidant activities were analyzed. The results exhibited that the molecular weight of NLCEPs-1 was 31.4 kDa and it was composed of rhamnose, glucose, galactose, xylose and arabinose in the molar percentage of 11.128: 63.770: 5.439: 6.585: 13.077. The backbone of NLCEPs-1 was mainly consisted of → )4-α-d-Glcp (1→, →6)-α-d-Glcp (1→, →1)-β-d-Galp and β-d-Galp-(1→. NLCEPs-1 exhibited the strong antioxidant activity in scavenging ability of various free radicals and immunomodulatory activity by the enhancement of the pinocytic capacity, nitric oxide (NO) and cytokines.

Influence of cations, pH and dispersed phases on pectin emulsification properties

The cooperativity of six cations (Ca²⁺, Mg²⁺, Zn²⁺, Al³⁺, Cr³⁺ and Fe³⁺), three pectins (sugar beet, high and low methyl esterified), three dispersed phases (medium chain triglycerides (MCT), orange oil and hexadecane), time (30 days) and pH (2.0 and 6.0) has been investigated in the formation and stability against coarsening of oil-in-water emulsions. Cations generally influenced emulsion stability in the following order (most stable) Ca²⁺ ​> ​Mg²⁺ ​> ​Al³⁺ ​> ​Cr³⁺ ​> ​Zn²⁺ ​> ​Fe³⁺ (least stable). This order largely coincided with that of the strength of pectin-cation interactions showing that the higher the affinity of cation for pectin the less stable the emulsion. More stable emulsions were formed with sugar beet pectin, which was also unresponsive to the presence of cations, followed by high- and then low-methyl esterified samples. At pH 2.0 all pectins showed their best emulsification performance whereas shifting pH to 6.0 severely impaired emulsification capacity and longer term stability against droplet growth. Smaller droplets were created with hexadecane under all conditions studied followed by MCT and orange oil in agreement with their aqueous solubilities. The present results advance our understanding of the stabilisation of emulsions using pectin and allow us to tailor their functionality for applications in food, pharmaceutical and biomedical industries.

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Cations influence stability in the order: Ca²⁺ ​> ​Mg²⁺ ​> ​Al³⁺ ​> ​Cr³⁺ ​> ​Zn²⁺ ​> ​Fe³⁺.

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Pectins showed best emulsification performance at pH 2.0

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Pectins showed poor emulsification performance at pH 6.0

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Pectin stability order: sugar beet ​> ​high methoxy ​> ​low methoxy pectin.

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Oil stability order at pH 2.0: hexadecane ​< ​medium chain triglycerides ​< ​orange oil.

Classification, structure and mechanism of antiviral polysaccharides derived from edible and medicinal fungus

The deficiency of chemical-synthesized antiviral drugs when applied in clinical therapy, such as drug resistance, and the lack of effective antiviral drugs to treat some newly emerging virus infections, such as COVID-19, promote the demand of novelty and safety anti-virus drug candidate from natural functional ingredient. Numerous studies have shown that some polysaccharides sourcing from edible and medicinal fungus (EMFs) exert direct or indirect anti-viral capacities. However, the internal connection of fungus type, polysaccharides structural characteristics, action mechanism was still unclear. Herein, our review focus on the two aspects, on the one hand, we discussed the type of anti-viral EMFs and the structural characteristics of polysaccharides to clarify the structure-activity relationship, on the other hand, the directly or indirectly antiviral mechanism of EMFs polysaccharides, including virus function suppression, immune-modulatory activity, anti-inflammatory activity, regulation of population balance of gut microbiota have been concluded to provide a comprehensive theory basis for better clinical utilization of EMFs polysaccharides as anti-viral agents.

Recent advances in polysaccharides from Lentinus edodes (Berk.): Isolation, structures and bioactivities

Lentinus edodes, an important edible mushroom cultivated in East Asia for thousands of years, has been widely used as food and medicinal ingredient worldwide. Modern phytochemistry studies have demonstrated that L. edodes is very rich in bioactive polysaccharides, especially the β-glucans. Over the past two decades, the isolation, chemical properties, and bioactivities of polysaccharides from fruiting bodies, mycelium and fermentation broth of L. edodes have been drawing much attention from scholars around the world. It has been demonstrated that L. edodes polysaccharides possess various remarkable biological activities, including anti-oxidant, anti-tumor, anti-aging, anti-inflammation, immunomodulatory, antiviral, and hepatoprotection effects. This review summarizes the recent development of polysaccharides from L. edodes including the isolation methods, structural features, bioactivities and mechanisms, and their structure-activity relationship, which can provide useful research underpinnings and update information for their further application as therapeutic agents and functional foods.

Isolation, purification and structural characterization of two pectin-type polysaccharides from Coreopsis tinctoria Nutt. and their proliferation activities on RAW264.7 cells

Coreopsis tinctoria Nutt. (C.tinctoria) is an annual herb of the Compositae family with many health benefits, such as clearing heat, antioxidant and anticancer activity. In this paper, two polysaccharides were isolated from C.tinctoria, named CTAP-1 and CTAP-2, respectively. Structure of CTAP-1and CTAP-2 were elucidated by high-performance gel permeation chromatography, chemical derivative analyses, GC-MS and NMR techniques. Results reveal that they both CTAP-1 and CTAP-2 consisted of predominant amounts of galacturonic acid residues along with small amounts of arabinose, rhamnose and galactose.Both them contain homogalacturonan and rhammnogalcturan I regions in different ratio, suggesting their pectin-type features. The proliferation activities of CTAP-1 and CTAP-2 on RAW264.7 cells in vitro were detected. Results show both them have the significant proliferation effect on RAW264.7 cells when the concentration from 40 to 200 µg/mL. Given their structural characteristics and proliferation activities, the pectins are expected to be potential natural immune modulators, which need further study.

Polysaccharides from Cordyceps miltaris cultured at different pH: Sugar composition and antioxidant activity

In the study, the β-glucan content, the primary structure and the antioxidant capacity of polysaccharides in Cordyceps militaris cultivated with different initial growth pH were evaluated. Meanwhile, the mechanism of β-glucan biosynthesis was investigated by RNA-Seq. Based on the results, C. militaris growing at an initial growth pH of 5-7 (CMsA) was distinguished from C. militaris growing at an initial growth pH of 8-9 (CMsB) and their unigenes showed the comparable expression. The mean of β-glucan content of CMsB group was 32.7% (w/w), 10% higher than that of CMsA. The results of RNA-seq showed 1088 differentially expressed genes between CMsA and CMsB groups. Furthermore, oxidative phosphorylation-related Gene ontology terms were up-regulated in CMsB groups. In addition, the results of structural analysis (FTIR spectrum, monosaccharide composition, periodate oxidation) and bioactivity evaluation speculated that C. militaris polysaccharides possessed higher β-(1 → 6)-glucan content and antioxidant activities in CMsB groups.

A novel exopolysaccharide from marine bacterium Pantoea sp. YU16-S3 accelerates cutaneous wound healing through Wnt/β-catenin pathway

Natural polysaccharides with versatile properties are the potential candidates for wound healing applications. In this study, an exopolysaccharide, EPS-S3, isolated from a marine bacteria Pantoea sp. YU16-S3 was evaluated for its wound-healing abilities by studying the key molecular mechanisms in vitro and in vivo. Basic characterisation showed EPS-S3 as a heteropolysaccharide with glucose, galactose, N-acetyl galactosamine and glucosamine. The molecular weight of EPS-S3 was estimated to be 1.75 × 10⁵ Da. It showed thermal stability up to 200 °C and shear-thickening non-Newtonian behaviour. It was biocompatible with dermal fibroblasts and keratinocytes and showed cell adhesion and cell proliferation properties. EPS-S3 facilitated cell migration in fibroblasts, induced rapid transition of cell cycle phases and also activated macrophages. In vivo experiments in rats showed the re-epithelialization of injured tissue with increased expression of HB-EGF, FGF, E-cadherin and β-catenin in EPS-S3 treatment. The results indicate that EPS-S3 modulates healing process through Wnt/β-catenin pathway due to its unique characteristics. In conclusion, EPS-S3 biosynthesized by the marine bacterium is a potential biomolecule for cutaneous wound healing applications.

Methods of extraction, separation, purification, structural characterization for polysaccharides from aquatic animals and their major pharmacological activities

The further development of fishery resources is a hotspot in the development of the fishery industry. However, how to develop aquatic animal resources deeply is a key point to be solved in the fishery industry. Over the past decades, numerous aquatic animals have gained great attention in the development and utilization of their bioactive molecules which are of therapeutic applications as nutraceuticals and pharmaceuticals. Recent research revealed that aquatic animals are composed of many vital moieties, such as polysaccharides and proteins, which provide health benefits beyond basic nutrition. In particular, aquatic animal polysaccharides are gaining worldwide popularity owing to their high content, ease of extraction, specific structure, few side effects, prominent therapeutic potential and incorporation in functional foods and dietary supplements. Thus, tremendous research on the isolation, identification and bioactivities of polysaccharides has been carried out. This review presents comprehensive viewpoints on extraction, separation, purification, structural characterization and bioactivity of various polysaccharides from aquatic animals, such as sea cucumber, abalone, oyster and mussels. In addition, this review profiled a brief knowledge on both current challenges and future scope in aquatic animal polysaccharides field. The review will be a direction of deep processing in fishery resources, which is a hotspot, but technical bottleneck. Furthermore, the review could be served as a useful reference material for further investigation, production and application of polysaccharides from aquatic animals in functional foods and therapeutic agents.

Ultrasonic-enhanced subcritical water extraction of polysaccharides by two steps and its characterization from Lentinus edodes

Some studies have demonstrated that polysaccharides are the chief ingredient of Lentinus edodes. To extract the useful polysaccharides from Lentinus edodes, we used a novel extraction method, which was named ultrasonic-enhanced subcritical water extraction by two steps (USWE). Four independent factors (extraction temperature, extraction time, liquid-to-solid ratio, and ultrasonic power) were studied. A Box-Behnken design (BBD) was applied to optimize the USWE condition based on the results of single-factor tests. The maximum extraction rate of polysaccharides was 17.34%. In addition, extracted polysaccharides at optimal condition were compared with subcritical water extraction (SWE), ultrasonic extraction (UE), and hot water extraction (HWE) samples. The antioxidant against 2,2‑diphenyl‑1‑picryl‑hydrazyl (DPPH) and reducing power were also evaluated. The IC₅₀ value for DPPH scavenging rate of HWE, SWE, UE, and USWE sample was 0.341, 0.237, 0.280, and 0.232 mg/mL, respectively. The USWE sample had the highest reducing power activity. The mole ratio of the monosaccharide composition of four samples was different. The results of AFM and SEM showed that the morphology of the four polysaccharides showed significant differences. These results revealed that USWE was an effective technique for extracting and separating polysaccharides from Lentinus edodes, which may be potentially applied in food, cosmetics, and medicines.

Dinuclear Lanthanide(III)-m-ODO2A-dimer Macrocyclic Complexes: Solution Speciation, DFT Calculations, Luminescence Properties, and Promoted Nitrophenyl-Phosphate Hydrolysis Rates

Potentiometric speciation studies, mass spectrometry, and DFT calculations helped to predict the various structural possibilities of the dinuclear trivalent lanthanide ion (Ln^III , Ln=La, Eu, Tb, Yb, Y) complexes of a novel macrocyclic ligand, m-ODO2A-dimer (H₄ L), to correlate with their luminescence properties and the promoted BNPP and HPNP phosphodiester bond hydrolysis reaction rates. The stability constants of the dinuclear Ln₂ (m-ODO2A-dimer) complexes and various hydrolytic species confirmed by mass spectrometry were determined. DFT calculations revealed that the Y₂ LH_-1 and the Y₂ LH_-2 species tended to form structures with the respective closed- and open-form conformations. Luminescence lifetime data for the heterodimetallic TbEuL system confirmed the fluorescence resonance energy transfer from the Tb^III to Eu^III ion. The internuclear distance R_TbEu values were estimated to be in the range of 9.4-11.3 Å (pH 6.7-10.6), which were comparable to those of the DFT calculated open-form conformations. Multiple linear regression analysis of the k_obs data was performed using the equation: k_obs,corr. =k_obs -k_obs,OH =kLn2LHM->1 [Ln₂ LH_-1 ]+kLn2LH-2 [Ln₂ LH_-2 ] for the observed Ln₂ L-promoted BNPP/HPNP hydrolysis reactions in solution pH from 7 to 10.5 (Ln=Eu, Yb). The results showed that the second-order rate constants for the Eu₂ LH_-2 and Yb₂ LH_-2 species were about 50-400 times more reactive than the structural analogous Zn₂ (m-12 N₃ O-dimer) system.

Bioactive Mushroom Polysaccharides: A Review on Monosaccharide Composition, Biosynthesis and Regulation

Mushrooms are widely distributed around the world and are heavily consumed because of their nutritional value and medicinal properties. Polysaccharides (PSs) are an important component of mushrooms, a major factor in their bioactive properties, and have been intensively studied during the past two decades. Monosaccharide composition/combinations are important determinants of PS bioactivities. This review summarizes: (i) monosaccharide composition/combinations in various mushroom PSs, and their relationships with PS bioactivities; (ii) possible biosynthetic pathways of mushroom PSs and effects of key enzymes on monosaccharide composition; (iii) regulation strategies in PS biosynthesis, and prospects for controllable biosynthesis of PSs with enhanced bioactivities.

Quantitative Structure Activity Relationship Models for the Antioxidant Activity of Polysaccharides

In this study, quantitative structure activity relationship (QSAR) models for the antioxidant activity of polysaccharides were developed with 50% effective concentration (EC50) as the dependent variable. To establish optimum QSAR models, multiple linear regressions (MLR), support vector machines (SVM) and artificial neural networks (ANN) were used, and 11 molecular descriptors were selected. The optimum QSAR model for predicting EC50 of DPPH-scavenging activity consisted of four major descriptors. MLR model gave EC50 = 0.033Ara-0.041GalA-0.03GlcA-0.025PC+0.484, and MLR fitted the training set with R = 0.807. ANN model gave the improvement of training set (R = 0.96, RMSE = 0.018) and test set (R = 0.933, RMSE = 0.055) which indicated that it was more accurately than SVM and MLR models for predicting the DPPH-scavenging activity of polysaccharides. 67 compounds were used for predicting EC50 of the hydroxyl radicals scavenging activity of polysaccharides. MLR model gave EC50 = 0.12PC+0.083Fuc+0.013Rha-0.02UA+0.372. A comparison of results from models indicated that ANN model (R = 0.944, RMSE = 0.119) was also the best one for predicting the hydroxyl radicals scavenging activity of polysaccharides. MLR and ANN models showed that Ara and GalA appeared critical in determining EC50 of DPPH-scavenging activity, and Fuc, Rha, uronic acid and protein content had a great effect on the hydroxyl radicals scavenging activity of polysaccharides. The antioxidant activity of polysaccharide usually was high in MW range of 4000-100000, and the antioxidant activity could be affected simultaneously by other polysaccharide properties, such as uronic acid and Ara.