Structural characteristics and biological activities of a pectic-polysaccharide from okra affected by ultrasound assisted metal-free Fenton reaction

Effect of ultrasound assisted H2O2/Vc treatment on the hyperbranched Lignosus rhinocerotis polysaccharide: Structures, hydrophobic microdomains, and antitumor activity

The effect of ultrasonic intensity (28.14, 70.35, and 112.56 W/cm2) on Lignosus rhinocerotis polysaccharide (LRP) degraded by ultrasound assisted H2O2/Vc system (U-H/V) was investigated. U-H/V broke the molecular chain of LRP and improved the conformational flexibility, decreasing the molecular weight, intrinsic viscosity ([η]) and particle size. The functional groups and hyperbranched structure of LRP were almost stable after U-H/V treatment, however, the triple helix structure of LRP was partially disrupted. With increasing ultrasonic intensity, the critical aggregation concentration increased from 0.59 mg/mL to 1.57 mg/mL, and the hydrophobic microdomains reduced. Furthermore, the LRP treated with U-H/V significantly inhibited HepG2 cell proliferation by inducing apoptosis. The increase in antitumor activity of LRP was closely associated with the reduction of molecular weight, [η], particle size and hydrophobic microdomains. These results revealed that U-H/V treatment facilitates the degradation of LRP and provides a better insight into the structure-antitumor activity relationship of LRP.

Potential structure-function relationships of pectic polysaccharides from quinoa microgreens: Impact of various esterification degrees

Pectic polysaccharides are one of the most vital functional ingredients in quinoa microgreens, which exhibit numerous health-promoting benefits. Nevertheless, the detailed information about the structure-function relationships of pectic polysaccharides from quinoa microgreens (QMP) remains unknown, thereby largely restricting their applications as functional foods or fortified ingredients. Therefore, to unveil the possible structure-function relationships of QMP, the mild alkali de-esterification was utilized to modify QMP, and then the correlations of esterification degrees of native and modified QMPs to their biological functions were systematically investigated. The results showed that the modified QMPs with different esterification degrees were successfully prepared by the mild alkali treatment, and the primary chemical structure (e.g., compositional monosaccharides and glycosidic linkages) of the native QMP was overall stable after the de-esterified modification. Furthermore, the results revealed that the antioxidant capacity, antiglycation effect, prebiotic potential, and immunostimulatory activity of the native QMP were negatively correlated to its esterification degree. In addition, both native and modified QMPs exerted immunostimulatory effects through activating the TLR4/NF-κB signaling pathway. These results are conducive to unveiling the precise structure-function relationships of QMP, and can also promote its applications as functional foods or fortified ingredients.

Impacts of ultrasound-assisted Fenton degradation and alkaline de-esterification on structural properties and biological effects of pectic polysaccharides from Tartary buckwheat leaves

Tartary buckwheat (Fagopyrum tataricum (L.) Gaertn) leaf has abundant rhamnogalacturonan-I enriched pectic polysaccharides, which exert various health-promoting effects. Nevertheless, the potential relationship between the chemical structure and the biological function of pectic polysaccharides from Tartary buckwheat leaves (TBP) remains unclear. Therefore, to bridge the gap between the chemical structure and the biological function of TBP, the impacts of ultrasound-assisted Fenton degradation (UFD) and mild alkaline de-esterification (MAD) on structural properties and biological effects of TBP were systematically studied. Compared with the native TBP (molecular mass, 9.537 × 104 Da), the molecular masses of degraded TBPs (TBP-MMW, 4.811 × 104 Da; TBP-LMW, 2.101 × 104 Da) were significantly reduced by the UFD modification, while their primary chemical structures were overall stable. Besides, compared with the native TBP (esterification degree, 22.73 %), the esterification degrees of de-esterified TBPs (TBP-MDE, 14.27 %; TBP-LDE, 6.59 %) were notably reduced by the MAD modification, while their primary chemical structures were also overall stable. Furthermore, the results revealed that both UFD and MAD modifications could significantly improve the antioxidant, antiglycation, and immunostimulatory effects of TBP. Indeed, TBP's biological effects were negatively correlated to its molecular mass and esterification degree, while positively linked to its free uronic acids. The findings demonstrate that both UFD and MAD modifications are promising techniques for the structural modification of TBP, which can remarkedly promote its biological effects. Besides, the present results are conducive to better understanding TBP's structure-bioactivity relationship.

In Vitro Digestion and Fermentation of Different Ethanol-Fractional Polysaccharides from Dendrobium officinale: Molecular Decomposition and Regulation on Gut Microbiota

Polysaccharides from Dendrobium officinale have garnered attention for their diverse and well-documented biological activities. In this study, we isolated three ethanol-fractionated polysaccharides from Dendrobium officinale (EPDO) and investigated their digestive properties and effects on gut microbiota regulation in vitro. The results indicated that after simulating digestion in saliva, gastric, and small intestinal fluids, three EPDOs, EPDO-40, EPDO-60 and EPDO-80, with molecular weights (Mw) of 442.6, 268.3 and 50.8 kDa, respectively, could reach the large intestine with a retention rate exceeding 95%. During in vitro fermentation, the EPDOs were broken down in a "melting" manner, resulting in a decrease in their Mw. EPDO-60 degraded more rapidly than EPDO-40, likely due to its moderate Mw. After 24 h, the total production of short-chain fatty acids (SCFAs) for EPDO-60 reached 51.2 ± 1.9 mmol/L, which was higher than that of EPDO-80. Additionally, there was an increase in the relative abundance of Bacteroides, which are capable of metabolizing polysaccharides. EPDO-60 also promoted the growth of specific microbiota, including Prevotella 9 and Parabacteroides, which could potentially benefit from these polysaccharides. Most notably, by comparing the gut microbiota produced by different fermentation carbon sources, we identified the eight most differential gut microbiota specialized in polysaccharide metabolism at the genus level. Functional prediction of these eight differential genera suggested roles in controlling replication and repair, regulating metabolism, and managing genetic information transmission. This provides a new reference for elucidating the specific mechanisms by which EPDOs influence the human body. These findings offer new evidence to explain how EPDOs differ in their digestive properties and contribute to the establishment of a healthy gut microbiota environment in the human body.

Efficient degradation and enhanced α-glucosidase inhibitory activity of apricot polysaccharides through non-thermal plasma assisted non-metallic Fenton reaction

Dielectric barrier discharge (DBD) was a commonly used non-thermal plasma (CP) technology. This paper aimed to enhance the biological activity of apricot polysaccharides (AP) by using dielectric barrier discharge (DBD-CP) assisted H2O2-VC Fenton reaction for degradation. The degradation conditions were optimized through response surface methodology. The molecular weight (Mw) of degraded apricot polysaccharides (DAP) was 19.71 kDa, which was 7.25 % of AP. The inhibition rate of DAP (2 mg/mL) was 82.8 ± 3.27 %, which was 106.87 % higher than that of AP. DBD-CP/H2O2-VC degradation changed the monosaccharide composition of AP and improved the linearity of polysaccharide chains. In addition, a novel apricot polysaccharide DAP-2 with a Mw of only 6.60 kDa was isolated from DAP. The repeating units of the main chain of DAP-2 were →4)-α-D-GalpA-(1 →, the branch chain was mainly composed of α-D-GalpA-(1 → 2)-α-L-Rhap-(1→ connected to O-3 position →3,4)-α-D-GalpA-(1→. The complex structure formed by the combination of DAP-2 and α-glucosidase was stable. DAP-2 had a higher α-glucosidase binding ability than the acarbose. These results suggested that DAP-2 had the potential to be developed as a potential hypoglycemic functional food and drug.

Comparison of soluble dietary fibers from various quinoa microgreens: Structural characteristics and bioactive properties

Quinoa (Chenopodium quinoa Willd.) microgreens are widely consumed as healthy vegetables around the world. Although soluble dietary fibers exist as the major bioactive macromolecules in quinoa microgreens, their structural characteristics and bioactive properties are still unclear. Therefore, the structural characteristics and bioactive properties of soluble dietary fibers from various quinoa microgreens (QMSDFs) were investigated in this study. The yields of QMSDFs ranged from 38.82 to 52.31 mg/g. Indeed, all QMSDFs were predominantly consisted of complex pectic-polysaccharides, e.g., homogalacturonan (HG) and rhamnogalacturonan I (RG I) pectic domains, with the molecular weights ranged from 2.405 × 104 to 5.538 × 104 Da. In addition, the proportions between RG I and HG pectic domains in all QMSDFs were estimated in the range of 1: 2.34-1: 4.73 (ratio of galacturonic acid/rhamnose). Furthermore, all QMSDFs exhibited marked in vitro antioxidant, antiglycation, prebiotic, and immunoregulatory effects, which may be partially correlated to their low molecular weights and low esterification degrees. These findings are helpful for revealing the structural and biological properties of QMSDFs, which can offer some new insights into further development of quinoa microgreens and related QMSDFs as value-added healthy products.

Efficient extraction of pectic polysaccharides from thinned unripe kiwifruits by deep eutectic solvent-based methods: Chemical structures and bioactivities

To promote the potentially industrial applications of thinned unripe kiwifruits, two deep eutectic solvent-based methods, including deep eutectic solvent-assisted extraction (DAE) and microwave-assisted deep eutectic solvent extraction (MDE), were optimized for the extraction of polysaccharides from thinned unripe kiwifruits (YKP). Results showed that the yields of YKP-D prepared by DAE and YKP-DM prepared by MDE were extremely higher than YKP-H prepared by hot water extraction. Furthermore, YKP-H, YKP-D, and YKP-DM were mainly composed of pectic polysaccharides, including homogalacturonan (HG) and rhamnogalacturonan I (RG I) domains. Besides, both YKP-D and YKP-DM exhibited stronger antioxidant, anti-glycosylation, and immunomodulatory effects than those of YKP-H, and their higher contents of uronic acids and bound polyphenols as well as lower molecular weights could partially contribute to their bioactivities. Overall, these results revealed that the developed MDE method could be utilized as a promising method for highly efficient extraction of YKP with superior beneficial effects.

Optimization of ultrasound-assisted extraction of Imperata cylindrica polysaccharides and evaluation of its anti-oxidant and amelioration of uric acid stimulated cell apoptosis

An efficient, cost-effective and environmentally friendly ultrasound-assisted hot water method for Imperata cylindrica polysaccharide (ICPs) extraction was developed. According to the response surface results, the optimal ultrasonic time was 85 min, ultrasonic power was 192.75 W, temperature was 90.74 °C, liquid-solid ratio was 26.1, and polysaccharide yield was 28.50 %. The polysaccharide mainly consisted of arabinose (Ara), galactose (Gal), and glucose (Glc), with a molecular weight of 62.3 kDa. Ultrasound-assisted extraction of Imperata cylindrica polysaccharide (UICP) exhibited stronger anti-oxidant activity and ability to ameliorate cellular damage due to uric acid stimulation compared with traditional hot water extraction of Imperata cylindrica polysaccharide (ICPC-b). It also exhibited higher thermal stability, indicating its potential value for applications in the food industry.

Improved Cordycepin Production by Cordyceps Militaris Using Corn Steep Liquor Hydrolysate as an Alternative Protein Nitrogen Source

Cordycepin production in the submerged culture of Cordyceps militaris was demonstrated using hydrolyzed corn processing protein by-products, known as corn steep liquor hydrolysate (CSLH), as an alternative nitrogen source. The growth, metabolism, and cordycepin production of Cordyceps militaris were evaluated under various concentrations of CSLH induction. The results demonstrated that CSLH addition had positive effects on the growth and cordycepin production with various C. militaris strains. The optimum strain, C. militaris GDMCC5.270, was found to effectively utilize CSLH to promote mycelium growth and cordycepin production. Low concentrations of CSLH (1.5 g/L) in the fermentation broth resulted in 343.03 ± 15.94 mg/L cordycepin production, which was 4.83 times higher than that of the group without CSLH. This also enhanced the metabolism of sugar, amino acids, and nucleotides, leading to improved cordycepin biosynthesis. The increase in key amino acids, such as glutamic acid, alanine, and aspartic acid, in the corn steep liquor hydrolysate significantly enhanced cordycepin yield. The corn steep liquor hydrolysate was confirmed to be a cost-effective accelerator for mycelium growth and cordycepin accumulation in C. militaris, replacing partial peptone as a cheap nitrogen source. It serves as a suitable alternative for efficient cordycepin production at a low cost.

The differential non-covalent binding of epicatechin and chlorogenic acid to ovotransferrin and the enhancing efficiency of immunomodulatory activity

Seeking safe and environmentally friendly natural immunomodulators is a pressing requirement of humanity. This study investigated the differential binding characteristics of two polar polyphenols (PP), namely epicatechin (EC) and chlorogenic acid (CA), to ovotransferrin (OVT), and explored the relationship between structural transformations and immunomodulatory activity of OVT-PP complexes. Results showed that CA exhibited a stronger affinity for OVT than EC, mainly driven by hydrogen bonds and van der Waals forces. Complexation-induced conformational variations in OVT, including static fluorescence quenching, increased microenvironment polarity surrounding tryptophan and tyrosine residues, and the transition from disordered α-helix to stable β-sheet. Furthermore, the structural conformation transformation of OVT-PP complexes facilitated the enhancement of immunomodulatory activity, with the OVT-CA (10:2) complex demonstrating the best immunomodulatory activity. Principal component analysis (PCA) and Pearson correlation analysis revealed the immunomodulatory activities of the OVT-PP complexes were influenced by surface hydrophobicity (negatively correlated), β-sheet percentage and polyphenol binding constants. It could be inferred that PP complexation increased the surface polarity of OVT, consequently enhancing its immunomodulatory activity by promoting cell membrane affinity and antigen recognition. This study provides valuable guidance for effectively utilizing polyphenol-protein complexes in enhancing immunomodulatory activity.

Structural characteristics and structure-activity relationship of four polysaccharides from Lycii fructus

At present, the structure-activity relationship of polysaccharides is a common and important focus in the fields of glycobiology and carbohydrate chemistry. To better understand the effect of specific polysaccharide structures on bioactive orientation, four homogeneous polysaccharides from Lycii fructus, one neutral along with three acidic polysaccharides, were purified, structurally characterized and comparatively evaluated on the antioxidative and anti-aging activities. The GC-MS-based monosaccharide composition analysis and methylation results showed that the LFPs had similar glycosyl types but varied proportions. Nuclear magnetic resonance (NMR) spectroscopy showed that LFPs consisted of arabinogalactan, rhamnogalacturonan and homogalacturonan structural domains. The results of the structure-activity relationship indicated that the antioxidative activity was positively correlated with the galacturonic acid (GalA) content, while the neutral multi-branched chains might be responsible for the anti-aging activity. This study is the first time to compare the principal structures and multiple biological activities of LFPs, which provided a reference for the industrial development and deep excavation of the health value of LFPs.

Structural properties and biological activities of soluble dietary fibers rich in pectic-polysaccharides from different buckwheat green leaves

Buckwheat green leaves are commonly consumed as functional tea materials due to their various beneficial effects. Although buckwheat green leaves have abundant soluble dietary fibers (SDFs), the information about their structural properties and functional properties remains unknown, largely hindering their applications as functional/health products. Hence, to enhance the usage and application of SDFs from buckwheat green leaves as value-added health products, the structures and biological activities of SDFs derived from different buckwheat green leaves were investigated and compared. Results revealed that SDFs derived from Tartary buckwheat green leaves (TBSDF) and common buckwheat green leaves (CBSDF) were rich in complex pectic-polysaccharides, mainly composing of homogalacturonan (HG) and rhamnogalacturonan I (RG I) pectic domains. Besides, TBSDF had higher proportion of RG I pectic domains than that of CBSDF. Furthermore, the existence of a high content of complex pectic-polysaccharides in TBSDF and CBSDF could contribute to their various biological activities, such as antioxidant, antiglycation, fat/bile acid binding, anticancer, and prebiotic effects. These results can provide some new insights into further development of buckwheat green leaves and related SDFs as value-added health products.

Preparation of Auricularia auricula polysaccharides and their protective effect on acute oxidative stress injury of Caenorhabditis elegans

This research enhanced the extraction procedure for Auricularia auricula crude polysaccharides by utilizing a modified Fenton reagent as a solvent, and obtained A. auricula polysaccharides (AAPs-VH) via alcohol precipitation and deproteinization. The HPLC profile revealed that the purified AAPs-VH using Sepharose 6FF was mainly a heteropolysaccharide, consisting primarily of mannose, glucuronic acid, glucose, and xylose. The Mw and Mn of the purified AAPs-VH were 87.646 kDa and 48.854 kDa, respectively. The FT-IR and NMR spectra revealed that the purified AAPs-VH belonged to pyranose and were mainly formed by (1 → 3)-linked-β-D glucan formation. In vivo experiments conducted with Caenorhabditis elegans, AAPs-VH was found to notably influence the lifespan, improve the antioxidant system, and decrease the level of cell apoptosis. This might be achieved by up-regulating the expression of genes in the IIS and TOR pathways. The study concludes that the modified Fenton reagent can increase Auricularia auricula polysaccharide solubleness and active sites, which may be an essential prompt for future studies.

Effect of in vitro digestion and fermentation of kiwifruit pomace polysaccharides on structural characteristics and human gut microbiota

Kiwifruit pomace is abundant in polysaccharides that exhibit diverse biological activities and prebiotic potential. This study delves into the digestive behavior and fermentation characteristics of kiwifruit pomace polysaccharides (KFP) through an in vitro simulated saliva-gastrointestinal digestion and fecal fermentation. The results reveal that following simulated digestion of KFP, its molecular weight reduced by 4.7%, and the reducing sugar (CR) increased by 9.5%. However, the monosaccharide composition and Fourier transform infrared spectroscopy characteristics showed no significant changes, suggesting that KFP remained undigested. Furthermore, even after saliva-gastrointestinal digestion, KFP retained in vitro hypolipidemic and hypoglycemic activities. Subsequently, fecal fermentation significantly altered the physicochemical properties of indigestible KFP (KFPI), particularly leading to an 89.71% reduction in CR. This indicates that gut microbiota could decompose KFPI and metabolize it into SCFAs. Moreover, after 48 h of KFPI fecal fermentation, it was observed that KFPI contributed to maintaining the balance of gut microbiota by promoting the proliferation of beneficial bacteria like Bacteroides, Lactobacillus, and Bifidobacterium, while inhibiting the unfavorable bacteria like Bilophila. In summary, this study offers a comprehensive exploration of in vitro digestion and fecal fermentation characteristics of KFP, providing valuable insights for potential development of KFP as a prebiotic for promoting intestinal health.

Modification methods, biological activities and applications of pectin: A review

Pectin is a complex and functionally rich natural plant polysaccharide that is widely used in food, medical, and cosmetic industries. It can be modified to improve its properties and expand its applications. Modification methods for natural pectin can be divided into physical, chemical, enzymatic, and compound methods. Different modification methods can result in modified pectins (MPs) exhibiting different physicochemical properties and biological activities. The objectives of this paper were to review the various pectin modification methods explored over the last decade, compare their differences, summarize the impact of different modification methods on the biological activity and physicochemical properties of pectin, and describe the applications of MPs in food and pharmaceutical fields. Finally, suggestions and perspectives for the development of MPs are discussed. This review offers a theoretical reference for the rational and efficient processing of pectin and the expansion of its applications.

A Multi-Component Nano-Co-Delivery System Utilizing Astragalus Polysaccharides as Carriers for Improving Biopharmaceutical Properties of Astragalus Flavonoids

Purpose

Enhancing the dissolution, permeation and absorption of active components with low solubility and poor permeability is crucial for maximizing therapeutic efficacy and optimizing functionality. The objective of this study is to investigate the potential of natural polysaccharides as carriers to improve the biopharmaceutical properties of active components.

Methods

In this study, we employed four representative flavonoids in Astragali Radix, namely Calycosin-7-O-β-D-glucoside (CAG), Ononin (ON), Calycosin (CA) and Formononetin (FMN), as a demonstration to evaluate the potential of Astragalus polysaccharides (APS) as carriers to improve the biopharmaceutical properties, sush as solubility, permeability, and absorption in vivo. In addition, the microstructure of the flavonoids-APS complexes was characterized, and the interaction mechanism between APS and flavonoids was investigated using multispectral technique and molecular dynamics simulation.

Results

The results showed that APS can self-assemble into aggregates with a porous structure and large surface area in aqueous solutions. These aggregates can be loaded with flavonoids through weak intermolecular interactions, such as hydrogen bonding, thereby improving their gastrointestinal stability, solubility, permeability and absorption in vivo.

Conclusion

We discovered the self-assembly properties of APS and its potential as carriers. Compared with introducing external excipients, the utilization of natural polysaccharides in plants as carriers may have a unique advantage in enhancing dissolution, permeation and absorption.

Exploring the partial degradation of polysaccharides: Structure, mechanism, bioactivities, and perspectives

Polysaccharides are promising biomolecules with lowtoxicity and diverse bioactivities in food processing and clinical drug development. However, an essential prerequisite for their applications is the fine structure characterization. Due to the complexity of polysaccharide structure, partial degradation is a powerful tool for fine structure analysis, which can effectively provide valid information on the structure of backbone and branching glycosidic fragments of complex polysaccharides. This review aims to conclude current methods of partial degradation employed for polysaccharide structural characterization, discuss the molecular mechanisms, and describe the molecular structure and solution properties of degraded polysaccharides. In addition, the effects of polysaccharide degradation on the conformational relationships between the molecular structure and bioactivities, such as antioxidant, antitumor, and immunomodulatory activities, are also discussed. Finally, we summarize the prospects and current challenges for the partial degradation of polysaccharides. This review will be of great value for the scientific elucidation of polysaccharide fine structures and potential applications.

How to effectively and greenly prepare multi-scale structural starch nanoparticles for strengthening gelatin film (ultrasound-Fenton system)

Ultrasound (US) assisted with Fenton (US-Fenton) reaction was developed to efficiently and greenly prepare starch nanoparticles (SNPs) that were employed as nanofillers to enhance gelatin (G) film properties. Compared to Fenton reaction alone, US-Fenton reaction significantly improved preparation efficiency and dispersion of SNPs (p < 0.05). An optimal US-Fenton reaction parameter (300 mM H2O2, ascorbic acid 55 mM, US 45 min) was found to prepare SNPs with uniform sizes (50-90 nm) and low molecular weight (Mn 7.91 × 105 Da). The XRD, FT-IR, and SAXS analysis revealed that the US-Fenton reaction degraded the amorphous and crystalline zones of starch from top to down, leading to the collapse of the original layered structure starch and the progressive formation of SNPs. The different sizes of SNPs were selected to prepare the composite films. The G-SNP3 film (with 50-90 nm SNPs) showed the most outstanding UV blocking, tensile, and barrier properties. Especially, the tensile strength of G-5%SNP3 film (containing 5 % SNPs) increased by 156 % and 6 % over that of G film and G-5%SNP2 film (containing 5%SNPs with 100-180 nm), respectively. Therefore, the nanomaterial was promisingly prepared by the US-Fenton system and provided a strategy for designing and producing nanocomposite films.

Comparison in structural, physicochemical and functional properties of sweet potato stems and leaves polysaccharide conjugates from different technologies

In order to better understand the influences of extraction techniques on the yield, characteristics, and bioactivities of polysaccharide conjugates, hot reflux extraction (HRE), ultrasonic-assisted extraction (UAE), microwave-assisted extraction (MAE), complex enzymolysis extraction (CEE), ultra-high pressure extraction (UPE), ultrasonic complex enzymes extraction (UEE) were used to extract sweet potato stems leaves polysaccharide conjugates (SPSPCs), and their physicochemical characteristics, functional properties, antioxidant and hypoglycemic activities were compared. Results showed that compared with HRE conjugate (HR-SPSPC), the yield, content of uronic acid (UAC), total phenol (TPC), total flavonoid (TFC) and sulfate group (SGC), water solubility (WS), percentage of glucuronic acid (GlcA), galacuronic acid (GalA) and galactose (Gal), antioxidant and hypoglycemia activities of UEE polysaccharide conjugates (UE-SPSPC) significant increased, while its molecular weight (Mw), degree of esterification (DE), content of protein (PC) and percentage of glucose (Glc) declined, but monosaccharides and amino acid types, and glycosyl linkages were not much different. Indeed, UE-SPSPC possessed the highest antioxidant activities and hypolipidemic activities among six SPSPCs, which might be due to the high UAC, TPC, TFC, SGC, GlcA, GalA and WS, low Mw, DE and Glc of UE-SPSPC. The results reveal that UEE is an effective extraction and modification technology of polysaccharide conjugates.

Comparison of Soluble Dietary Fibers Extracted from Ten Traditional Legumes: Physicochemical Properties and Biological Functions

Soluble dietary fibers (SDFs) exist as the major bioactive components in legumes, which exhibit various biological functions. To improve the potential applications of legume SDFs as healthy value-added products in the functional food industry, the physicochemical properties and biological functions of SDFs from ten selected traditional legumes, including mung bean, adzuki bean, red bean, red sword bean, black bean, red kidney bean, speckled kidney bean, common bean, white hyacinth bean, and pea, were studied and compared. Results showed that the physicochemical properties of SDFs varied in different species of legumes. All legume SDFs almost consisted of complex polysaccharides, which were rich in pectic-polysaccharides, e.g., homogalacturonan (HG) and rhamnogalacturonan I (RG I) domains. In addition, hemicelluloses, such as arabinoxylan, xyloglucan, and galactomannan, existed in almost all legume SDFs, and a large number of galactomannans existed in SDFs from black beans. Furthermore, all legume SDFs exhibited potential antioxidant, antiglycation, immunostimulatory, and prebiotic effects, and their biological functions differed relative to their chemical structures. The findings can help reveal the physicochemical and biological properties of different legume SDFs, which can also provide some insights into the further development of legume SDFs as functional food ingredients.

Effects of Extraction Methods on the Physicochemical Properties and Biological Activities of Polysaccharides from Polygonatum sibiricum

Polygonatum sibiricum polysaccharides (PSPs) have important biological functions, such as antioxidation, immunomodulatory, and hypolipidemic functions. Different extraction methods have effects on their structures and activities. In this study, six extraction methods, including hot water extraction (HWE), alkali extraction (AAE), ultrasound-assisted extraction (UAE), enzyme-assisted extraction (EAE), microwave-assisted extraction (MAE), and freeze-thaw-assisted extraction (FAE) were used to extract PSPs, and their structure-activity relationships were analyzed. The results showed that all six PSPs had similar functional group compositions, thermal stability, and glycosidic bond compositions. PSP-As (PSPs extracted by AAE) exhibited better rheological properties due to their higher molecular weight (Mw). PSP-Es (PSPs extracted by EAE) and PSP-Fs (PSPs extracted by FAE) had better lipid-lowering activity due to their lower Mw. PSP-Es and PSP-Ms (PSPs extracted by MAE), which do not contain uronic acid and have a moderate Mw, had better 1,1-diphenyl-2-picrylhydrazyl (DPPH)-radical-scavenging activity. On the contrary, PSP-Hs (PSPs extracted by HWE) and PSP-Fs, with the Mw of uronic acid, had the best OH-radical-scavenging activity. The high-Mw PSP-As had the best Fe²⁺-chelating ability. In addition, mannose (Man) may play an important role in the immunomodulatory activity. These results indicate that different extraction methods affect the structure and biological activity of polysaccharides to varying degrees, and these results are helpful for understanding the structure-activity relationship of PSPs.

Structural characteristics of mixed pectin from ginseng berry and its anti-obesity effects by regulating the intestinal flora

Ginseng berry is the mature berry of ginseng and its polysaccharide has hypolipidaemic effect, but its mechanism remains unclear. A pectin (GBPA) with a molecular weight of 3.53 × 10⁴ Da was isolated from ginseng berry, it was mainly composed of Rha (25.54 %), GalA (34.21 %), Gal (14.09 %) and Ara (16.25 %). Structural analysis showed that GBPA is a mixed pectin containing rhamnogalacturonan-I and homogalacturonan domains and has a triple helix structure. GBPA distinctly improved lipid disorders in obese rats, and changed intestinal flora with enrichments of Akkermansia, Bifidobacterium, Bacteroides and Prevotella, improved the levels of acetic acid, propionic acid, butyric acid and valeric acid. Serum metabolites which involved in the lipid regulation-related pathway, including cinnzeylanine, 10-Hydroxy-8-nor-2-fenchanone glucoside, armillaribin, 24-Propylcholestan-3-ol, were also greatly changed after GBPA treatment. GBPA activated AMP-activated protein kinase, phosphorylated acetyl-CoA carboxylase, and reduced the expression of lipid synthesis-related genes sterol regulatory element-binding protein-1c and fatty acid synthases. The regulatory effects of GBPA on lipid disorders in obese rats are related to the regulation of intestinal flora and activation of AMP-activated protein kinase pathway. Ginseng berry pectin could be considered in the future as a health food or medicine to prevent obesity.

Sulfated Undaria pinnatifida Polysaccharide Promotes Endocytosis of Nano-Calcium Oxalate Dihydrate by Repairing Subcellular Organelles in HK-2 Cells

The clinical manifestation of primary hyperoxaluria includes hyperoxaluria and recurrent urinary calculi. In this study, an oxidative damage model was constructed based on oxalate damage to the human renal proximal tubular epithelial cells (HK-2), and a comparative study was carried out on four different sulfated levels of Undaria pinnatifida polysaccharides (UPP0, UPP1, UPP2, and UPP3 with sulfate group [-OSO₃^-] contents of 1.59%, 6.03%, 20.83%, and 36.39%, respectively) on the repair of oxidatively damaged HK-2 cells. The results showed that after repair by UPPs, cell viability was enhanced, healing ability was improved, the intracellular superoxide dismutase level and mitochondrial membrane potential were increased, malondialdehyde, reactive oxygen species, and intracellular Ca²⁺ levels were reduced, cellular autophagy was reduced; lysosomal integrity was improved, and cytoskeleton and cell morphology were restored. The ability of repaired cells to endocytose nano-calcium oxalate dihydrate crystals (nano-COD) was enhanced. The activity of UPPs was closely related to their -OSO₃^- content. A too high or too low -OSO₃^- content was not conducive to polysaccharide activity, and only UPP2 exhibited the best cell repair ability and strongest ability to promote the cell endocytosis of crystals. UPP2 may be used as a potential agent to inhibit CaOx crystal deposition caused by high oxalate concentration.

Structure and potential anti-fatigue mechanism of polysaccharides from Bupleurum chinense DC

Two polysaccharides, BCP-1 and BCP-2, were obtained from Bupleurum chinense DC. by water extraction and ultrafiltration. BCP-1 (1.04 × 10⁵ Da) and BCP-2 (2.14 × 10⁴ Da) were composed of Mannose, Rhamnose, Glucose, Galactose, Arabinose, and Galacturonic acid in different proportions. They both contained oligogalacturonides in their main chain. Besides, the backbone of BCP-1 was composed of 4-β-Galp and 4,6-β-Glcp, and branched at C4 of 4,6-β-Glcp. While BCP-2 contained a backbone of 3,5-α-Araf residues with branches at C3. BCP-2 effectively extended the forced swimming time, improved the glycogen reserves and antioxidant system, decreased the levels of blood urea nitrogen, lactic acid, lactate dehydrogenase and creatinine kinase expression. It alleviated physical fatigue through regulating 5'-AMP-activated protein kinase (AMPK) and Nuclear Factor erythroid 2-Related Factor 2 (Nrf2) signalling pathway in skeletal muscles. This study demonstrated that BCP-2 exhibited more effective anti-fatigue activity than BCP-1 potentially associated with its primary and higher structures.

Effect of ultrasonic degradation on the structural feature, physicochemical property and bioactivity of plant and microbial polysaccharides: A review

With the bioactivities of antioxidant, anti-bacteria, anti-inflammation, immune regulation, antitumor and anti-coagulation, plant and microbial polysaccharides have been widely used in foods, medicine and cosmetics. However, how structure features affect the physicochemical property and bioactivity of plant and microbial polysaccharides is still unclear. Ultrasonic degradation usually degrades or modifies plant and microbial polysaccharides with different physicochemical properties and bioactivities by affecting their chemical or spatial structures via mechanical bond breaking and cavitation effects. Therefore, ultrasonic degradation might be an effective strategy for producing bioactive plant and microbial polysaccharides and analyzing their structure-function relationship. Present review summarized the influence of ultrasonic degradation on structural feature, physicochemical property and bioactivity of plant and microbial polysaccharides. Moreover, further problems need to be paid attention to during the application of ultrasonication for plant and microbial polysaccharides degradation are also recommended. Overall, present review will provide an efficient method for producing enhanced bioactive plant and microbial polysaccharides and analyzing their structure-activity relationship based on ultrasonic degradation.

Low-temperature plasma modification, structural characterization and anti-diabetic activity of an apricot pectic polysaccharide

To fully research the anti-diabetic activity of apricot polysaccharide, low temperature plasma (LTP) was used to modify apricot polysaccharide. The modified polysaccharide was isolated and purified using column chromatography. It was found that LTP modification can significantly improve the α-glucosidase glucosidase inhibition rate of apricot polysaccharides. The isolated fraction FAPP-2D with HG domain showed excellent anti-diabetic activity in insulin resistance model in L6 cell. We found that FAPP-2D increased the ADP/ATP ratio and inhibited PKA phosphorylation, activating the LKB1-AMPK pathway. Moreover, FAPP-2D activated AMPK-PGC1α pathway, which could stimulated mitochondrial production and regulate energy metabolism, promoting GLUT4 protein transport to achieve an anti-diabetic effect. The Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy data showed that the LTP modification could increase the CH bond content while decreasing the C-O-C/C-O bond content, indicating that LTP destroyed the C-O-C/C-O bond, which enhanced the anti-diabetes activity of the modified apricot pectin polysaccharide. Our findings could pave the way for the molecular exploitation of apricot polysaccharides and the application of low-temperature plasma.

Effects of ageing time on the properties of polysaccharide in tangerine peel and its bacterial community

To evaluate the effect of aging time on the quality of tangerine peel (TP) from the perspective of TP polysaccharide (TPP), five polysaccharide samples with different aging times named TPP-0/1/5/10/15 were prepared. Under the conditions of pH 0.5, solid-liquid ratio 1:25 and 80 °C, the TPPs extraction yield ranged from 20.35% to 27.68%. Compared with TPP-0, TPP-1/5/10/15 possesses low molecular weight (Mw) and high methoxy group content. In addition, TPP-15 had the most potent antioxidant activity. And the content of acidic polysaccharides in TPPs was negatively correlated with neutral polysaccharides during aging. Based on the analysis of 16srDNA, the dominant bacteria (Brevundimonas and Pseudomonas) in TP-10 might be critical flora to affect TP quality. This study provided basic information on the relationship between the TPPs and aging time, which could promote a new view to develop TP, and shorten the aging time during TP production.

Extraction, Structural, and Antioxidant Properties of Oligosaccharides Hydrolyzed from Panax notoginseng by Ultrasonic-Assisted Fenton Degradation

Plant polysaccharides exhibit many biological activities that are remarkably affected by molecular size and structures. This study aimed to investigate the degradation effect of ultrasonic-assisted Fenton reaction on the Panax notoginseng polysaccharide (PP). PP and its three degradation products (PP3, PP5, and PP7) were obtained from optimized hot water extraction and different Fenton reaction treatments, respectively. The results showed that the molecular weight (Mw) of the degraded fractions significantly decreased after treatment with the Fenton reaction. But the backbone characteristics and conformational structure were similar between PP and PP-degraded products, which was estimated by comparing monosaccharides composition, functional group signals in FT-IR spectra, X-ray differential patterns, and proton signals in ¹H NMR. In addition, PP7, with an Mw of 5.89 kDa, exhibited stronger antioxidant activities in both the chemiluminescence-based and HHL5 cell-based methods. The results indicated that ultrasonic-assisted Fenton degradation might be used to improve the biological activities of natural polysaccharides by adjusting the molecular size.

Physicochemical characteristics and biological activities of soluble dietary fibers isolated from the leaves of different quinoa cultivars

Quinoa leaf is consumed as a promising value-added vegetable in the diet. Although quinoa leaf is rich in soluble dietary fibers, the knowledge regarding their chemical structures and biological activities is still limited, which astricts their application in the functional food industry. Thus, to improve the precise use and application of soluble dietary fibers (SDFs) isolated from quinoa leaves in the food industry, the physicochemical structures and bioactivities of SDFs isolated from different quinoa leaves were systematically investigated. Results indicated that quinoa leaves were rich in SDFs, ranging from 3.30 % to 4.55 % (w/w). Quinoa SDFs were mainly composed of acidic polysaccharides, such as homogalacturonan and rhamnogalacturonan I, which had the molecular weights in the range of 4.228 × 10⁴ -7.059 × 10⁴ Da. Besides, quinoa SDFs exerted potential in vitro antioxidant activities, lipid and bile acid-adsorption capacities, immunoregulatory activities, and prebiotic effects, which might be partially associated with their molecular mass, content of uronic acid, and content of bound polyphenol. Collectively, these findings are beneficial to better understanding the chemical structures and bioactivities of SDFs extracted from different quinoa leaves, which can also provide a scientific basis for developing quinoa SDFs into functional foods in the food industry.

Structural Characteristic and In-Vitro Anticancer Activities of Dandelion Leaf Polysaccharides from Pressurized Hot Water Extraction

Dandelion (Taraxacum mongolicum Hand.-Mazz.) is a medicinal and edible plant. Dandelion has great development value for its health promoting benefits; additionally, Dandelion grows almost anywhere in the world. In this study, we report the structural characteristics and anti-cancer activity of novel dandelion leaf polysaccharides extracted by pressurized hot water extraction at 120 °C (DLP120) with Mw relative to dextran of 1.64 × 10⁶ Da. Structural analysis indicated that DLP120 is a complex polysaccharide composed of pectin and arabinogalactan. It was mainly composed of arabinose (32.35 mol%) and galactose (44.91 mol%). The main glycosidic linkages of DLP120 were 4-β-D-Galp, 4-α-D-GalpA, T-β-D-Galp, 5-α-L-Araf, 3,5-α-L-Araf, and T-α-L-Araf. In vitro, DLP120 inhibited HepG2 cell proliferation in a dose-dependent manner by inducing cell apoptosis. Cell cycle detection results revealed that DLP120 mainly arrests the cell cycle in S phase. Cells treated with DLP120 displayed obvious apoptotic morphology, including cell volume shrinks and cytoskeleton breaks down. In short, DLP120 has potential as an anti-cancer agent.

Mushroom polysaccharides with potential in anti-diabetes: Biological mechanisms, extraction, and future perspectives: A review

Diabetes mellitus (DM) is a global health threat. Searching for anti-diabetic components from natural resources is of intense interest to scientists. Mushroom polysaccharides have received growing attention in anti-diabetes fields due to their advantages in broad resources, structure diversity, and multiple bioactivities, which are considered an unlimited source of healthy active components potentially applied in functional foods and nutraceuticals. In this review, the current knowledge about the roles of oxidative stress in the pathogenesis of DM, the extraction method of mushroom polysaccharides, and their potential biological mechanisms associated with anti-diabetes, including antioxidant, hypolipidemic, anti-inflammatory, and gut microbiota modulatory actions, were summarized based on a variety of in vitro and in vivo studies, with aiming at better understanding the roles of mushroom polysaccharides in the prevention and management of DM and its complications. Finally, future perspectives including bridging the gap between the intervention of mushroom polysaccharides and the modulation of insulin signaling pathway, revealing structure-bioactivity of mushroom polysaccharides, developing synergistic foods, conducting well-controlled clinical trials that may be very helpful in discovering valuable mushroom polysaccharides and better applications of mushroom polysaccharides in diabetic control were proposed.

Preparation and Characterization of Ginger Peel Polysaccharide-Zn (II) Complexes and Evaluation of Anti-Inflammatory Activity

The present study aimed to explore the improvement of the bioactivity of ginger peel polysaccharides (GPs) by the modification of zinc after structural characterization. The obtained GP-Zn (II) complexes consisted dominantly of glucose and galactose in a mass proportion of 95.10:2.10, with a molecular weight of 4.90 × 10⁵ Da and a Zn content of 21.17 mg/g. The chelation of GPs and Zn (II) was mainly involved in the O-H of hydroxyl groups, and this interaction reduced the crystallinity and decreased the asymmetry of GPs, with a slight effect on the thermal stability. The administration of GPs and their Zn (II) complexes effectively alleviated CuSO₄-induced inflammatory response in zebrafish (Tg: zlyz-EGFP) via down-regulating the mRNA expression levels of pro-inflammatory cytokines (IL-1β, IL-6, IL-8, IL-12 and TNF-α) and upregulating the expression of anti-inflammatory cytokine (IL-10). Furthermore, the modification of Zn (II) enhanced the inflammation-inhibiting effect of polysaccharides. Therefore, GP-Zn (II) complexes could be applied as a candidate anti-inflammatory agent for the treatment of chronic inflammation-related diseases.

Production, characterization and antioxidant activity of exopolysaccharide from Sporidiobolus pararoseus PFY-Z1

At present, the study on exopolysaccharid is mainly focused on lactic acid bacteria, and the research on exopolysaccharide produced by yeast, especially Sporidiobolus pararoseus, is relatively few. Therefore, the aim of this study was to explore the characterization and antioxidant activities of a novel neutral exopolysaccharide SPZ, which was isolated and purified from S. pararoseus PFY-Z1. The results showed that SPZ was mainly composed of mannose, followed by glucose, with a molecular weight was 24.98 kDa, had O-glycosidic bonds, no crystalline, and no triple helix structure. Based on fourier transform-infrared, high-performance liquid chromatography and nuclear magnetic resonance analyses, SPZ was identified to be a exopolysaccharide with some side chains, presence of α-, β-pyranose ring and nine sugar residues. Furthermore, the morphology features of SPZ have performed a relatively rough and uneven surface, covered with small pores and fissures. Moreover, SPZ had higher antioxidant activities and the maximum scavenging abilities of ⋅OH, NO₂^- and reducing power were 28.05 ± 0.73%, 92.76 ± 1.86% and 0.345 ± 0.024, respectively. Hence, SPZ could be used as a potential antioxidant application in the food and pharmaceutical industries.

Critical review on alterations in physiochemical properties and molecular structure of natural polysaccharides upon ultrasonication

Natural polymers, such as polysaccharides, cellulose, and starch, have been widely used in the chemical engineering, medicine, food, and cosmetics industries, which had a great many of biological activities. Natural polysaccharides origin from algae, fungi and plants were components of human diet since antique times. Ultrasonication achieved the breakage the polysaccharides reticulum in an ordered fashion. The factors of temperature, ratio of water/material, sonication frequency, time of exposure, pH of the sonication medium influenced the polysaccharide digestion. Sonication improved the enzyme catalysis over its substrate molecule. Positive health promoting slow digestive starch and resistant starch can be prepared quite easily by the sonication process. The aim of this review is to present the current status and scope of natural polymers as well as some emerging polymers with special characteristic. The physiochemical properties and molecular structure of natural carbohydrates under ultrasonic irradiation were also discussed. Moreover, Polysaccharide based films had industrial applications is formed by ultrasonication. Polysaccharide nanoparticles obtained by sonication had efficient water holding capacity. Sonication is an advanced method to improve the food quality. Hence, this review describes the effects of ultrasonication on physical, chemical, and molecular structure of natural polysaccharides.

Effects of various degrees of esterification on antioxidant and immunostimulatory activities of okra pectic-polysaccharides

Pectic-polysaccharides are considered as one of the most abundant bioactive components in okra, which possess various promising health-promoting effects. However, the knowledge regarding the structure-bioactivity relationship of okra pectic-polysaccharides (OPP) is still limited. In this study, effects of various degrees of esterification (DEs) on in vitro antioxidant and immunostimulatory activities of OPP were analyzed. Results displayed that OPP with high (42.13%), middle (25.88%), and low (4.77%) DE values were successfully prepared by mild alkaline de-esterification, and their primary chemical structures (compositional monosaccharide and glycosidic linkage) and molecular characteristics (molecular weight distribution, particle size, and rheological property) were overall stable. Additionally, results showed that the notable decrease of DE value did not significantly affect antioxidant activities [2,2'-azino-bis (3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) and nitric oxide (NO) radical scavenging abilities as well as ferric reducing antioxidant power (FRAP)] of OPP, suggesting that the DE was not closely related to its antioxidant activity. In fact, the slight decrease of antioxidant activity of OPP after the alkaline de-esterification might be attributed to the slight decrease of uronic acid content. Nevertheless, the immunostimulatory effect of OPP was closely related to its DE, and a suitable degree of acetylation was beneficial to its in vitro immunostimulatory effect. Besides, the complete de-acetylation resulted in a remarkable reduction of immune response. The findings are beneficial to better understanding the effect of DE value on antioxidant and immunomodulatory activities of OPP, which also provide theoretical foundations for developing OPP as functional foods or health products.

Physicochemical properties and immune-enhancing activity of graded polysaccharides from the peels of stem lettuce (Lactuca sativa) by cascade membrane technology

In this study, cascade membrane technology was applied to classify polysaccharides from the peels of stem lettuce (PPSLs), and three graded polysaccharides (PPSL100, PPSL10, and PPSL1) were obtained using ultrafiltration membranes of 100, 10, and 1 kDa in sequence. The physicochemical properties and immune-modulatory activity of three PPSLs fractions were analyzed and compared. Results showed that all three fractions have characteristic absorption peak of polysaccharides determined by FT-IR, and their monosaccharide composition only consisted of glucose determined by HPLC. PPSL10 had the highest contents of total sugar (88.09 ± 3.52%), uronic acid (2.55 ± 0.10%), and sulfate group (4.15 ± 0.20%). Besides, all three fractions exhibited immune-enhancing activities using RAW264.7 macrophages model, and PPSL10 was the best able to promote phagocytosis of neutral red and nitric oxide generation, which might relate to the high contents of above compositions and medium molecular weight (32 kDa). The findings indicated that PPSL10 could be developed as immune-modulator in the field of functional foods.

Pumpkin Skin Polysaccharide–Zn(II) Complex: Preparation, Characterization, and Suppression of Inflammation in Zebrafish

In this study, pumpkin (Cucurbita moschata) skin polysaccharide–zinc(II) (PSP−Zn) complex was successfully prepared. The structure and physicochemical properties of PSP and PSP−Zn were analyzed. The anti-inflammatory activity of PSP and PSP−Zn was investigated in zebrafish larvae induced by copper sulphate. PSP and PSP−Zn consisted of rhamnose, arabinose, galactose, glucose, and galacturonic acid. The molecular weight (Mw) of PSP and PSP−Zn were 3.034 × 10⁶ and 3.222 × 10⁶ Da, respectively. Fourier transform infrared spectrum (FT-IR) and circular dichroism (CD) analysis results suggested that the chemical modification of zinc might occur through hydroxyl groups of PSP. The PSP−Zn complex had lamellar texture, smooth surface morphology, and larger particle size. X-ray Diffraction (XRD) analysis revealed that both PSP and PSP−Zn were semi-crystalline substances. PSP−Zn solution showed superior stability in a weak acid and alkaline environment, especially at pH = 6.0. Moreover, PSP and PSP−Zn showed a good inhibitory effect on inflammation cells in zebrafish. Real-time quantitative polymerase chain reaction (RT-PCR) result suggested that the anti-inflammatory mechanism of PSP and PSP−Zn were through downregulation of the expression of nitric oxide synthase 2b (nos2b), inducible nitric oxide synthase (iNOS), interleukin-6 (IL-6), and nuclear factor-kappa B2 (NF-κB2). The present study indicated that PSP−Zn is expected to be a safe and efficient novel zinc supplement with anti-inflammatory activity.

Microwave-Assisted Deep Eutectic Solvent Extraction, Structural Characteristics, and Biological Functions of Polysaccharides from Sweet Tea (Lithocarpus litseifolius) Leaves

The leaf of sweet tea (Lithocarpus litseifolius) is widely used as an edible and medicinal plant in China, which is rich in bioactive polysaccharides. In order to explore and promote the application of sweet tea polysaccharides in the functional food industry, the microwave-assisted deep eutectic solvent extraction (MDAE) of polysaccharides from sweet tea leaves was optimized, and the structural properties and biological functions of sweet tea polysaccharides prepared by MDAE (P-DM) were investigated and compared with that of hot water extraction (P-W). The maximum yield (4.16% ± 0.09%, w/w) of P-DM was obtained under the optimal extraction conditions (extraction time of 11.0 min, extraction power of 576.0 W, water content in deep eutectic solvent of 21.0%, and liquid–solid ratio of 29.0 mL/g). Additionally, P-DM and P-W possessed similar constituent monosaccharides and glycosidic bonds, and the homogalacturonan (HG) and arabinogalactan (AG) might exist in both P-DM and P-W. Notably, the lower molecular weight, higher content of total uronic acids, and higher content of conjugated polyphenols were observed in P-DW compared to P-W, which might contribute to its much stronger in vitro antioxidant, anti-diabetic, antiglycation, and prebiotic effects. Besides, both P-DW and P-W exhibited remarkable in vitro immunostimulatory effects. The findings from the present study indicate that the MDAE has good potential to be used for efficient extraction of bioactive polysaccharides from sweet tea leaves and P-DM can be developed as functional food ingredients in the food industry.

Influence of ultrasound assisted metal-free Fenton reaction on the structural characteristic and immunostimulatory activity of a β-D-glucan isolated from Dictyophora indusiata

The present study aimed to evaluate the influence of ultrasound assisted H₂O₂/ascorbic acid reaction on the structural characteristic and immunostimulatory activity of a β-D-glucan isolated from D. indusiata, so as to reveal its potential structure-immunostimulatory activity relationship. A purified β-D-glucan, named as DP, was quickly isolated from D. indusiata, and further identified as a 1,3-β-D-glucan with 1,6-β-D-Glcp as branched chains, which exhibited a rigid rod chain conformation in 0.9 % (w/v) of NaCl solution. Furthermore, results showed that the primary structure of DP was overall stable after the degradation by ultrasound assisted H₂O₂/ascorbic acid reaction. However, the molar mass and chain conformation of DP obviously changed. In addition, DP and its degraded products exerted remarkable immunostimulatory activity in vitro and in vivo, which could activate the nuclear factor-κB (NF-κB) signaling pathway through toll-like receptor 4 (TLR4). Indeed, the immunostimulatory activity of DP was closely-correlated to its molar mass and chain conformation. An appropriate degradation of molar mass could promote its immunostimulatory activity. While the transformation of chain conformation from rigid rod to random coil could cause the significant decrease of its immunostimulatory activity. These findings are beneficial to better understanding the structure-immunostimulatory activity relationship of β-D-glucans from edible mushrooms.

Current advances and potential trends of the polysaccharides derived from medicinal mushrooms sanghuang

For thousands of years, sanghuang is distinctive as a general designation for a group of precious and rare Chinese medicinal mushrooms. Numerous investigations have revealed that polysaccharide is one of the important biological active ingredients of sanghuang with various excellent biological activities, including antioxidant, anti-aging, anti-tumor, immunomodulatory, anti-inflammatory, anti-diabetic, hepatoprotective, and anti-microbial functionalities. For the past two decades, preparation, structural characterization, and reliable bioactivities of the polysaccharides from fruiting bodies, cultured mycelia, and fermentation broth of sanghuang have been arousing extensive interest, and particularly, different strains, sources, and isolation protocols might result in obvious discrepancies in structural features and bioactivities. Therefore, this review summarizes the recent reports on preparation strategies, structural features, bioactivities, and structure-activity relationships of sanghuang polysaccharides, which will enrich the knowledge on the values of natural sanghuang polysaccharides and support their further development and utilization as therapeutic agents, vaccines, and functional foods in tonic and clinical treatment.

Characterization and Antibacterial Activities of Carboxymethylated Paramylon from Euglena gracilis

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

Extraction, isolation, structural characterization, and antioxidant activity of polysaccharides from elderberry fruit

The isolation, purification, and antioxidant activity of polysaccharides extracted from elderberry fruits were studied. Two neutral polysaccharides (EFP-0 and EFP-1) and three acidic polysaccharides (EFP-2, EFP-3, and EFP-4) were isolated from elderberry. EFP-0, EFP-1, EFP-2, EFP-3, and EFP-4 all contain arabinose, galactose, glucose, and mannose, with molecular weights of 1.7981 × 10⁶, 7.0523 × 10⁶, 7.7638 × 10⁶, 4.3855 × 10⁵, and 7.3173 × 10⁵ Da, respectively. Structural characterization showed that the backbone of EFP-2 consisted of →4)-Manp (1→4)-β-D-Glcp (1→ and →4)-β-D-Glcp (1→5)-α-L-Araf (1→units, and T-α-L-Araf (1→ and T-β-D-Galp (1→ residues were detected by methylation analysis and NMR analysis. In addition, the MTT assay and zebrafish oxidative damage assay showed that EFP-2 had a protective effect on H₂O₂-damaged RAW264.7 cells in a dose-dependent manner, and zebrafish with the addition of EFP-2 would have low levels of ROS in vivo which showed significant antioxidant activity. Therefore, the results showed that the elderberry polysaccharides have antioxidant activity and can be used as potential antioxidants in functional foods.