Characterization of selenized polysaccharides from Ribes nigrum L. and its inhibitory effects on α-amylase and α-glucosidase

Green construction and digestive properties of Fe (II) and quercetin double-loaded delivery system by wampee polysaccharide and its application

This study was aimed to investigate green synthesis of wampee polysaccharide-Fe (II), called PQ-Fe (II), and its potential to load quercetin. Results showed that molecular weight of PQ-Fe (II) was 2.48 × 106 Da and it was composed of mannose, rhamnose, glucuronic acid, glucose, galactose with Fe (II) content being 84 %. Structural characterization proved the formation of FeO bonds and its average particle size was 68.1 nm, zeta potential being -30.1 mV. Moreover, Fe (II) and quercetin double-loaded delivery system PQ-Fe(II)-QR was successfully constructed and applied in gummy candies, which achieved 84.37 % loading efficiency of quercetin with excellent stability. When PQ-Fe(II)-QR concentration was 1 mg/mL, the scavenging rate of hydroxyl radical and DPPH radical were 51.7 % and 94.3 % respectively, and its inhibition rate on α-glucosidase reached 93.2 %. Moreover, PQ-Fe(II)-QR had high bioavailability during simulated digestion in vitro. These results highlighted that PQ-Fe(II)-QR had great prospect in iron supplement and nutrient delivery.

Ultrasound-assisted extraction, purification, sulfation of Perilla leaves polysaccharide and hypoglycemic and hypolipidemic activities

Perilla leaves are a common traditional medicinal and edible crop, in order to further explore its medicinal value, after determining the optimal ultrasound-assisted extraction conditions a neutral polysaccharide was extracted. Its structure was analyzed, and sulfation modification was carried out. After purification by different column chromatography, the optimal process for sulfation modification of PLP-2-1 was established, and sulfated modified PLP-2-1 (S-PLP-2-1) was successfully prepared. The potential structural framework and molecular weight of PLP-2-1 were determined by high performance liquid chromatography (HPLC), methylation analysis, and nuclear magnetic resonance (NMR) techniques, while sulfated modified S-PLP-2-1 maintained a high degree of structural similarity to PLP-2-1. Particle size analysis, Zeta potential measurement, infrared spectroscopy, and NMR analysis confirmed the presence of sulfate groups in S-PLP-2-1, while thermogravimetric and rheological analyses provided support for the development and utilization of these two polysaccharides. After determined the safe concentration range in vitro, the antioxidant and hypoglycemic activities of PLP-2-1 and S-PLP-2-1 were measured. Besides, the effects on the levels of total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) in oleic acid (OA) induced high-fat HepG2 cells of both polysaccharides were determined. The results indicated that the various biological activities of S-PLP-2-1 were significantly enhanced after sulfation modification. Therefore, PLP-2-1 and S-PLP-2-1 have the potential to be developed as drugs for anti-glycolipid metabolism disorders.

Physicochemical, antioxidant, gastrointestinal digestion and probiotic growth promoting properties of water and alkali extracted polysaccharides from Schizophyllum commune

BACKGROUND

Schizophyllum commune is a traditional edible and medicinal mushroom that has been successfully artificially cultivated in China. Polysaccharides from S. commune have attracted much attention because of their bioactivity. The present study aimed to investigate the physicochemical, gastrointestinal digestion and probiotic growth promoting properties of water extracted polysaccharides (WSP) and alkali extracted polysaccharides (WSP) from S. commune.

RESULTS

The extraction rates and the total sugar contents of WSP and ASP were 11.97% and 14.36% and 57.71 g kg-1 and 52.34 g kg-1, respectively. The main monosaccharides of WSP are glucose and mannose, whereas glucose, mannose and galacturonic acid are the main monosaccharides of ASP. Although the molecular weight of WSP is greater than that of ASP, both WSP and ASP show the typical absorption peaks of polysaccharides and a triple helix structure. WSP shows a coarse granular microstructure, whereas ASP presents a dense porous microstructure. Moreover, WSP shows typical Newtonian fluid behavior, whereas ASP exhibits typical non-Newtonian fluid behavior. WSP presents better thermal stability and antioxidant properties than that of ASP. Both WSP and ASP have good hydrolysis resistance in vitro simulated digestion, but ASP shows better hydrolysis resistance. Both WSP and ASP can promote the growth of probiotic, but the promoting growth effect depends on the strain of the probiotic.

CONCLUSION

In sum, WSP shows better physicochemical properties, but ASP has more potential to be an excellent prebiotic. © 2025 Society of Chemical Industry.

Structure characterization of polysaccharide isolated from Ribes nigrum L. and it's bioactivity against gout

Gout mainly caused by the increase of uric acid level in serum poses a threat to human health. Inhibition on the activity of xanthine oxidase (XOD) usually an effective method for treating gout, so finding XOD inhibitors without side effects is crucial. In this study, two heteropolysaccharides were extracted from blackcurrant by microwave-assisted aqueous two-phase technology, and the top phase (PRNP-1) and bottom phase (PRNP-2) polysaccharides at high purity (>86%) were obtained after column chromatography separation. Methylation and NMR analyses confirmed the potential structural backbone of PRNP-1 may be composed of →3)-α-L-Araf-(1 → 3)-β-D-Galp-(1 → 4)-β-D-Manp-(1 → 5)-α-Araf-(1 → 4)-α-D-GalpA-(1 → 3,6)-β-D-Glup-(1→, while PRNP-2 exhibited a differing repeating unit of →4)-β-D-Manp-(1 → 3)-α-D-Araf-(1 → 3)-β-D-Galp-(1 → 5)-α-Araf-(1 → 4)-α-D-GalpA-(1 → 3,6)-β-D-Glup-(1→. Compared to PRNP-1 (4.87 × 104 kDa), PRNP-2 with low molecular weight (2.30 × 104 kDa) exhibited better dispersivity, homogeneity, water solubility and thermal stability, as well as XOD inhibitory activity. Both PRNP-1 and PRNP-2 demonstrated a competitive, reversible inhibition towards XOD and quenched its fluorescence through forming polysaccharide-XOD complexes. Molecular docking and molecular dynamics simulation assays revealed that PRNP-2 exhibited a better binding capacity with XOD than PRNP-1. PRNPs markedly decreased the serum concentration of uric acid and creatinine, and XOD activity in hyperuricemia mice model. Therefore, PRNPs may be the potential natural therapeutic agents for the treatment of gout.

Structural elucidation, antioxidant and neuroprotective features of Physalis pubescens L. polysaccharide and its selenium-modified product

A novel polysaccharide, named as PPFP, was isolated from Physalis pubescens L. fruits with a molecular weight of 229.3 kDa. Further Structural characterisation revealed that PPFP comprised of rhamnose, arabinose, fucose, mannose and glucose, and the predominantly backbone is linked with 1 → 3- and 1 → 6-glycosidic bonds. Using the HNO3-Na2SeO3 method, the selenium-modified derivative (Se-PPFP) was successfully synthesised with higher bioavailability. FT-IR and NMR analyses confirmed selenium was attached to the Se-PPFP structure with the Se=O and O-Se-O forms. More specifically, selenium was bound to the C-6 bond on the D-pyranose of PPFP. Se-PPFP showed reduced molecular weight, looser microstructure and better thermal stability than PPFP. PPFP and Se-PPFP exhibited notable antioxidant and neuroprotective effects, with Se-PPFP being more significant. These findings suggest their potential as functional food antioxidants.

Comparative study of Idesia polycarpa Maxim cake meal polysaccharides: Conventional versus innovative extraction methods and their impact on structural features, emulsifying, antiglycation, and hypoglycemic properties

Idesia polycarpa Maxim (IPM) cake meal, a major by-product of oil extraction, is often discarded in large quantities, resulting in considerable waste. This study explored the extraction of IPM polysaccharides (IPMPs) from cake meal using the innovative ultrasonic-assisted three-phase partitioning (UTPP) method, in comparison with conventional techniques, including acid, medium-temperature alkali, chelating agent, and enzyme extraction methods. The IPMP-UT prepared via UTPP method achieved superior extraction efficiency (10.05 %), increased uronic acid content (39.12 %), and a greater proportion of the rhamnogalacturonan I (RG-I) domain (42.88 %), along with improved homogeneity (Mw/Mn: 2.79) and enhanced functional properties, including improved thermal stability, emulsion ability, and emulsion stability. Compared to IPMPs extracted via conventional methods, emulsions stabilized with IPMP-UT exhibited superior performance across different pH levels and polysaccharide concentrations. At pH 6.0, IPMP-UT emulsion formed thicker interfacial layers and exhibited the strongest storage (G') and loss (G″) module. Bioactivity assays further revealed that IPMP-UT had the most potent in vitro inhibition of α-glucosidase and was the most effective at reducing the formation of fructosamine, α-dicarbonyl compounds, and advanced glycation end products (AGEs). All IPMPs inhibited α-glucosidase through a combined mechanism, primarily reducing fluorescence via static quenching, with IPMP-UT demonstrating the greatest binding affinity. Fluorescence and FT-IR spectroscopy confirmed that IPMPs induced structural rearrangements in the enzyme. In conclusion, the UTPP method emerged as the most promising and environmentally sustainable technique for producing pectic polysaccharides with optimal functional properties from IPM cake meal.

Mechanistic Insights Into the Inhibitory Effects of Arabinoxylan and (1,3)(1,4)-β-Glucan on Starch Digestive Enzymes

The intake of dietary fiber can reduce the risk of several major chronic diseases, including colorectal cancer, obesity, type II diabetes, and cardiovascular diseases. Endogenous dietary fibers such as arabinoxylan (AX) and (1,3)(1,4)-β-glucan (BG), which have good palatability, are more suitable for addition to cereal foods. We studied starch digestion in the gelatinized AX/BG-starch complexes. To clarify the synergistic role of AX and BG in the starch digestion process and explore the effect of cell wall polysaccharides on the activity of digestive enzymes, the mechanism of action between cell wall polysaccharides and digestive enzymes was analyzed through fluorescence spectroscopy, UV-visible absorption spectroscopy, and infrared spectroscopy. The results of the interaction between cell wall polysaccharides and digestive enzymes showed that the higher the proportion of AX, the stronger the quenching effect on digestive enzymes and the lower the enzyme activity. During the digestion of the AX/BG-starch complexes, in addition to binding to the active sites of enzymes to reduce enzyme activity, AX and BG played a dominant role as barriers. On one hand, they prevented some water molecules from entering the interior of starch granules to inhibit gelatinization. On the other hand, they effectively reduced the bioaccessibility of digestive enzymes.

Antioxidant and hepatic fibrosis-alleviating effects of selenium-modified Bletilla striata polysaccharide

Liver fibrosis is a significant precursor to cirrhosis and liver cancer, yet effective treatments remain elusive. Our previous studies demonstrated that Bletilla striata polysaccharide (BSP) has therapeutic effects, though it performed poorly at medium concentrations. To address this limitation, BSP underwent selenization modification. In this study, selenized BSP (Se-BSP) was structurally characterized, and its in vivo activity in alleviating liver fibrosis was evaluated. The results showed that the molecular weight of Se-BSP increased, its in vitro antioxidant activity improved, and it exhibited enhanced efficacy in alleviating liver fibrosis at medium concentrations (150 mg/kg) compared to BSP. These findings provide a theoretical basis for the potential application of Se-BSP as an anti-liver fibrosis agent.

Structural characterization of Eurotium cristatum spore polysaccharide and its hypoglycemic and hypolipidemic ability in vitro

Fuzhuan brick tea is a Chinese fermented tea with hypoglycemic and hypolipidemic properties. Eurotium cristatum plays an important role in the fermentation of Fuzhuan brick tea, and the E. cristatum spore content is important for evaluating the quality of Fuzhuan brick tea. In this study, an E. cristatum spores polysaccharide (ECSP-1), was isolated for the first time. The average molecular weight of ECSP-1 was approximately 28.64 kDa, and it consisted of mannose and galactose at a molecular molar ratio of 1:3.97. The maximum percentage of residues in ECSP-1 was →5)-β-D-Galf-(1→. ECSP-1 has a core chain formed by mannopyranose via α-(1 → 6) glycosidic bonds. Approximately 75 % of mannose on the core chain has a long branched chain attached at C-2. The branched chain is a galactan composed of →5)-β-D-Galf-(1→ and →3)-β-D-Galf-(1→. ECSP-1 inhibited α-glucosidase, α-amylase, and pancreatic lipase in vitro; this inhibition was reversible competitive inhibition. ECSP-1 also possesses the ability to bind glycylcholate sodium and taurocholate sodium. Thus, ECSP-1 has potential hypoglycemic and hypolipidemic abilities and has the potential to be developed into hypoglycemic and hypolipidemic drugs or healthcare products.

Critical review of the criterion of polysaccharide purity

Natural polysaccharides attract scientists and industries' interest with diverse applications in biomaterials, immune regulation, gut microbiota regulation, food additives, and more. Nevertheless, the absence of standardized purity criteria created significant challenges in characterizing polysaccharides, leading to varied and complicated structures, and impeding progress in research and development. Consequently, it is essential to obtain samples that adhere to high-level and unified purity standards for effective polysaccharide research. Herein we review current methods for assessing polysaccharide purity, emphasizing a commonly neglected impurity: mixtures of polysaccharides with similar molecular sizes. Such a mixture, previously regarded as a single sample, can present a much more complex and ambiguous chemical structure. To address this challenge, we propose enhancing the purity criteria to identify these mixtures. Briefly, the molecular size changes are monitored following hydrolysis with diagnostic enzymes which are identified through methylation and monosaccharide analysis. A pure polymer will exhibit a complete shift in its HPGPC peak, while a polymer mixture will display residual peaks. Establishing standardized criteria for assessing polysaccharide quality represents a significant milestone in the industrialization of these important biomolecules. By enabling accurate, consistent, reliable characterization, this advancement lays the groundwork for broader polysaccharide applications in pharmaceuticals, food, materials, and beyond.

Comparative study on the effects of different drying technologies on the structural characteristics and biological activities of polysaccharides from Idesia polycarpa maxim cake meal

To extract oil, the fruits of Idesia polycarpa Maxim (IPM) must first undergo a drying process. This study aimed to investigate how different industrial drying techniques-microwave vacuum drying (MVD), microwave drying, infrared drying, and hot air drying-affect the structural characteristics and bioactivities of IPM cake meal polysaccharides (IPMPs). The results revealed significant differences in the structure and composition of the four IPMPs. MVD-IPMP, dried using MVD, exhibited a lower molecular weight (346.26 kDa), higher uronic acid content (30.74 %), and a distinct triple-helix structure. These structural features contributed to its enhanced antioxidant activity, α-glucosidase inhibition, and prevention of glycation. IPMPs induced secondary conformational changes in α-glucosidase, leading to decreased enzyme activity. Additionally, IPMPs caused static quenching of the enzyme's intrinsic fluorescence, suggesting a specific interaction mechanism, with MVD-IPMP demonstrating the highest binding affinity. These findings suggest that MVD is an effective technique for the large-scale production of high-quality IPMPs.

Optimization of ultrasonic-assisted deep eutectic solvent extraction, characterization, and bioactivities of polysaccharides from Eucommia ulmoides

For the valorization of Eucommia ulmoides (EU) for the functional food industry, the process of ultrasonic-assisted deep eutectic solvent (DES) extraction of EU polysaccharides (EUP) was optimized by response surface methodology. After response surface analysis and experimental verification, the optimum extraction conditions were as follows: the molar ratio of choline chloride to oxalic acid was 0.9:1, the water content of DES was 40.28%, the ratio of material to liquid was 1:22 g/mL, the time was 90 min, and the power was 320 W. The extraction rate of EUP was 1.71%, which was higher than the extraction rate of 0.75% by ultrasonic water extraction under the same conditions, and the optimization effect was better. After DEAE column gradient elution and Sephadex G-75 gel column chromatography, the elution curve and a refined polysaccharide (EUP-1) were obtained. The IC50 values of EUP-1 against α-glucosidase and α-amylase were 0.091 and 0.011 mg/mL. The IC50 values of EUP-1 on DPPH and ABTS·+ scavenging were 0.065 and 0.065 mg/mL. The monosaccharide composition of EUP-1 was analyzed as mannose, rhamnose, glucuronic acid, and galacturonic acid in the following molar ratio: 1.00: 1.28: 1.53: 1.88.

Isolation, In Vitro Antioxidant Capacity, Hypoglycemic Activity and Immunoactivity Evaluation of Polysaccharides from Coriandrum sativum L

Coriander (Coriandrum sativum) is a classical medicinal and edible herb as well as a spice, but the physicochemical and biological properties of its polysaccharides have not been fully studied. In this study, the polysaccharides were extracted using an ultrasonic-assisted method and purified from fresh coriander, and then the coriander polysaccharide (CSP) fraction was separated using an agarose gel Q-Sepharose Fast Flow column. The total sugar content, protein content and monosaccharides composition of CSPs were determined using a phenol-sulfuric acid method, Coomassie Brilliant Blue method and HPLC. The structural characterization was detected using ultraviolet spectrophotometry and FT-IR spectroscopy. DPPH and ABTS free radicals were used to explore their antioxidant activities, while the inhibitory abilities of α-amylase and α-glucosidase were used to evaluate their hypoglycemic activity. After that, the immunomodulatory and antitumor activities were investigated using macrophage RAW264.7 and HepG2 cells as the targets. The results showed that the total sugar and protein contents of CSPs were 66.90 ± 1.44% and 1.06 ± 0.32%, respectively. CSPs were mainly composed of fucose, rhamnose, arabinose, galactose, glucose, galacturonic acid and glucuronic acid, with a molar ratio of 1.13:15.11:9.60:25.98:1.55:44.33:2.29, and may be an acidic heteropolysaccharide containing pyran rings, α- and β-glycosidic bonds and glucuronic acid. Results from in vitro experiments of biological activities showed that the IC50 of CSPs for scavenging DPPH and ABTS free radicals were 0.759 mg/mL and 1.758 mg/mL, respectively; the IC50 values for inhibiting the activities of α-amylase and α-glucosidase were 0.634 mg/mL and 2.178 mg/mL, respectively; the CSPs with a concentration of 25~200 μg/mL showed no obvious toxicity to macrophage RAW264.7, and when treated with 100 μg/mL of CSPs, the relative cell phagocytosis capacity and secreted nitric oxide amount of RAW264.7 were 153.75 ± 12.01% and 133.56 ± 5.37%, respectively; CSPs showed a concentration-dependent ability to inhibit the growth of HepG2 cells within the test concentration of 0.25-2.0 mg/mL. Summarizing the results, due to their excellent antioxidant, immunomodulatory and anti-tumor activities, the coriander acid polysaccharides were expected to show good potential in comprehensive development of food and medicine.

Covalent Modification of Selenium in Polysaccharide Enhances Immunoregulation Activity via the TLR4-Mediated MAPK/NF-κB Signaling Pathway

Selenium (Se) is a crucial trace element that demonstrates significant immunomodulatory effects, which are attributed to the variability in its valence states and metabolic pathways. To investigate the Se-related immunoregulatory effects, locust bean gum (LBG), a typical galactomannan, was selenized by employing deep eutectic solvents (DESs) as high-efficiency solvents to obtain Se-covalent modified LBG (SeLBGs) with similar molecular mass and different Se contents (SeLBGL, 1049.57 and SeLBGH, 4926.54 μg/g). After introducing selenite into LBG, SeLBGs display greater immunomodulatory activities by activating MAPKs and NF-κB signaling pathways compared with LBG and Se compounds (Se-Met, Na2SeO3, and SeNPs) at the same Se equivalent, which are confirmed by their higher cell viability, phagocytic activity, secretion of cytokines, and protein expression. In addition, molecular docking and molecular dynamics suggest that SeLBG has the potential to induce dimerization of subunits and activate toll-like receptors (TLRs). By employing the specific receptor inhibitors strategy, it is confirmed that the combination of Se and LBG enhances TLR2/4 recognition according to the results of cytokine secretion and MAPKs/NF-κB pathway-related protein expression. These findings underscore the role of Se in pattern receptor recognition and the potential of Se-enriched ingredients in various functions.

Effect of Planting Systems on the Physicochemical Properties and Bioactivities of Strawberry Polysaccharides

Suitable planting systems are critical for the physicochemical and bioactivities of strawberry (Fragaria × ananassa Duch.) polysaccharides (SPs). In this study, SPs were prepared through hot water extraction, and the differences in physicochemical characteristics and bioactivities between SPs derived from elevated matrix soilless planting strawberries (EP-SP) and those from and conventional soil planting strawberries (GP-SP) were investigated. A higher extraction yield was observed for EP-SP (5.88%) than for GP-SP (4.67%), and slightly higher values were measured for the average molecular weight (632.10 kDa vs. 611.88 kDa) and total sugar content (39.38% vs. 34.92%) in EP-SP. In contrast, a higher protein content (2.12% vs. 1.65%) and a more ordered molecular arrangement were exhibited by GP-SP. Monosaccharide composition analysis revealed that EP-SP contained higher levels of rhamnose (12.33%) and glucose (49.29%), whereas GP-SP was richer in galactose (11.06%) and galacturonic acid (19.12%). Thermal analysis indicated only minor differences in decomposition temperatures (approximately 225-226 °C) and thermal stability between the samples. However, GP-SP showed a higher enthalpy change (ΔHg = 18.74 J/g) compared to EP-SP (13.93 J/g). Biological activity assays revealed that GP-SP generally exerted stronger non-enzymatic glycation inhibition at both early and final stages (IC50: 7.47 mg/mL vs. 7.82 mg/mL and 11.18 mg/mL vs. 11.87 mg/mL, respectively), whereas EP-SP was more effective against intermediate α-dicarbonyl compounds (maximum inhibition of 75.32%). Additionally, GP-SP exerted superior α-glucosidase inhibition (IC50 = 2.4583 mg/mL), in line with kinetic and fluorescence quenching analyses showing a higher enzyme-substrate complex binding affinity (Kis = 1.6682 mg/mL; Ka = 5.1352 × 105 M-1). Rheological measurements demonstrated that EP-SP solutions exhibited a pronounced increase in apparent viscosity at higher concentrations (reaching 3477.30 mPa·s at 0.1 s-1 and 70 mg/mL) and a stronger shear-thinning behavior, while GP-SP showed a comparatively lower viscosity and lower network order. These findings suggest that different planting systems significantly affect both the molecular structures and functionalities of SPs, with GP-SP demonstrating enhanced hypoglycemic and anti-glycation properties. It is therefore recommended that suitable planting systems be selected to optimize the functionality of plant-derived polysaccharides for potential applications in the food and pharmaceutical industries.

Simultaneous extraction of oil, protein and polysaccharide from Idesia polycarpa Maxim cake meal using ultrasound combined with three phase partitioning

This study explored the potential of ultrasonic-assisted three-phase partitioning (UTPP) to simultaneously extract lipids, proteins, and polysaccharides from Idesia polycarpa Maxim (IPM) cake meal, a significant byproduct of oil extraction. The impact of variables such as inorganic salt type, solid-liquid ratio, salt concentration, pH, ultrasonic time, temperature, and volume of dimethyl carbonate was examined. Based on the single-factor tests and response surface methodology (RSM), optimal conditions were identified as 30 % ammonium citrate, a 1:26 solid-liquid ratio, pH 3, 31 min of ultrasonic time, 30 °C temperature, and 15 mL of dimethyl carbonate. These conditions achieved extraction rates of 8.10 % for lipids, 5.03 % for proteins, and 10.03 % for polysaccharides, with recovery rates of 91.62 %, 83.08 %, and 93.95 % respectively. Chemical analysis showed the lipid fraction rich in linoleic acid, and the protein fraction high in glutamic acid, aspartate, and serine. The polysaccharide fraction, mainly RG-I pectin with a molecular weight of 226.58 kDa, exhibited strong thermal stability and inhibitory effects on α-glucosidase and glycation, suggesting potential for functional food and dietary supplement applications. This highlights UTPP as a sustainable method for effectively utilizing valuable compounds from IPM cake meal, outperforming traditional extraction techniques.

Selenium polysaccharide form sweet corn cob mediated hypoglycemic effects in vitro and untargeted metabolomics study on type 2 diabetes

Type 2 diabetes mellitus (T2D) causes complications due to metabolic disorders besides increasing blood glucose. Sweet corn cob selenium polysaccharide (SeSCP) is a complex of Se with Sweet corn cob polysaccharide that has good hypoglycemic efficacy, but its effect on T2D metabolism has not been determined. In this study, the hypoglycemic effect of SeSCP was investigated by in vitro and in vivo experiments, and the levels of metabolites in feces were analyzed in a high-fat diet and STZ-induced T2D mouse model by Liquid chromatography-mass spectrometry (LC-MS). The results indicated that SeSCP regulates α-amylase and α-glucosidase through competitive reversible inhibition, and the reaction is spontaneous, driven by van der Waals forces and hydrogen bonding. In vivo, SeSCP modulates glucose transport decreasing glucose entry into the bloodstream. The metabolites mainly affected by SeSCP-MC were adenine, LysoPA (0:0/18:2(9Z, 12Z)), cysteine-S-sulfate, and demeclocycline (hydrochloride) metabolites. SeSCP interfered with β-alanine metabolism, starch and sucrose metabolism, ether lipid metabolism, glycerophospholipid metabolism, glyoxylate and dicarboxylate metabolism, pantothenate and CoA biosynthesis, etc. Additionally, SeSCP exhibited more effective metabolic interventions than metformin and SCP. Therefore, SeSCP can reduce complications while improving T2D blood glucose.

Advances in microbial exopolysaccharides as α-amylase inhibitors: Effects, structure-activity relationships, and anti-diabetic effects in vivo

The rapid digestion of starch, as the main source of energy in the human diet, causes an acute increase in blood sugar levels that will affect blood glucose homeostasis. The inhibition of α-amylase activity is an effective way of reducing starch digestibility, thereby controlling postprandial glycemia. As a class of carbohydrate polymers, microbial exopolysaccharides (EPSs) have garnered widespread attention for their inhibitory effects on α-amylase, but there is a lack of comprehensive review in this area. This paper aimed to review the inhibitory activity of microbial EPSs on α-amylase and their interaction mechanisms, and the effect of microbial EPSs on lowering blood glucose levels and regulating glycolipid metabolism in vivo were also discussed. Numerous studies have reported that EPSs with α-amylase inhibition activity are primarily produced by lactic acid bacteria. Microbial EPSs with an appropriate range of molecular weight, high proportion of glucose or mannose or arabinose residues, and high uronic acid content might be acceptable to inhibit α-amylase activity. Additionally, microbial EPSs exhibited potential anti-diabetic effects in mice, reducing blood glucose levels, and regulating glycolipid metabolism and gut microbiota. The information covered in this review may enhance the development and application of EPSs in functional food and pharmaceutical research.

Enhancement of Antioxidative and Anti-Inflammatory Activities of Corn Silk Polysaccharides After Selenium Modification

Objective

This study aimed to study the effect of selenium modification on the bioactivity of corn silk polysaccharides, particularly its antioxidant and anti-inflammatory functions.

Methods

HNO3-NaSeO3 was used to selenize degraded corn silk polysaccharides (DCSP). The structure and physicochemical properties of DCSP and selenized corn silk polysaccharides (Se-DCSP) were characterized by inductively coupled plasma emission spectroscopy, Fourier-transform infrared, ultraviolet-visible spectroscopy, nuclear magnetic resonance, nanometer, scanning electron microscopy, and thermogravimetric analysis. The protective effects of DCSP and Se-DCSP on HK-2 cells damaged by nano-calcium oxalate and the changes of inflammatory factors were detected by laser confocal microscopy, flow cytometry, and fluorescence microscopy.

Results

The selenium content of DCSP and Se-DCSP were 19.5 and 1226.7 μg/g, respectively. Compared with DCSP, Se-DCSP showed significantly improved biological activity, including the scavenging ability of various free radicals (increased by about 2-3 times), the intracellular reactive oxygen content (decreased by about 1.5 times), and the mitochondrial membrane potential (decreased by about 2.5 times). Moreover, cell viability and morphological recovery ability were improved. Compared with DCSP, Se-DCSP significantly down-regulated HK-2 cell inflammatory factors MCP-1 (about 1.7 times), NLRP3, and NO (about 1.5 times).

Conclusion

The antioxidant activity and the ability to down-regulate the expression of inflammatory factors of Se-DCSP were significantly enhanced compared with DCSP, and Se-DCSP can better protect HK-2 cells from oxidative damage, indicating that Se-DCSP has a stronger potential ability to inhibit kidney stone formation.

Comparative study on physicochemical properties and hypoglycemic activities of intracellular and extracellular polysaccharides from submerged fermentation of Morchella esculenta

The structural characteristic, physicochemical properties and structure-hypoglycemic activity relationship of intracellular (IPS) and extracellular (EPS) from submerged fermentation of Morchella esculenta were systematically compared and assessed. Both IPS and EPS were neutral, with a triple-helical conformation, and composed of galactose, glucose and mannose monosaccharides in different molar ratios. The molecular weight and particle size of IPS were higher than those of EPS. FTIR and SEM showed that the main functional group absorption peak intensity, glycosidic bond type and surface morphology of the two polysaccharides differed. Analysis of rheological and thermal properties revealed that the viscosity of IPS was higher than that of EPS, while thermal stability of EPS was greater than that of IPS. Hypoglycemic activity analysis in vitro showed that both IPS and EPS were non-competitive inhibitors of α-amylase and α-glucosidase. EPS showed strong digestive enzyme inhibitory activity due to its higher sulphate content and molar ratio of galactose, lower Mw and particle size. Meanwhile, with its higher Mw and apparent viscosity, IPS showed stronger glucose adsorption capacity and glucose diffusion retardation. These results indicate that IPS and EPS differed considerably in structure and physicochemical properties, which ultimately led to differences in hypoglycemic activity. These results not only suggested that IPS and EPS has the potential to be functional foods or hypoglycemic drugs, but also provided a new target for the prevention and treatment of diabetes with natural polysaccharides.

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

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

Interactions between Gut Microbiota and Natural Bioactive Polysaccharides in Metabolic Diseases: Review

The gut microbiota constitutes a complex ecosystem, comprising trillions of microbes that have co-evolved with their host over hundreds of millions of years. Over the past decade, a growing body of knowledge has underscored the intricate connections among diet, gut microbiota, and human health. Bioactive polysaccharides (BPs) from natural sources like medicinal plants, seaweeds, and fungi have diverse biological functions including antioxidant, immunoregulatory, and metabolic activities. Their effects are closely tied to the gut microbiota, which metabolizes BPs into health-influencing compounds. Understanding how BPs and gut microbiota interact is critical for harnessing their potential health benefits. This review provides an overview of the human gut microbiota, focusing on its role in metabolic diseases like obesity, type II diabetes mellitus, non-alcoholic fatty liver disease, and cardiovascular diseases. It explores the basic characteristics of several BPs and their impact on gut microbiota. Given their significance for human health, we summarize the biological functions of these BPs, particularly in terms of immunoregulatory activities, blood sugar, and hypolipidemic effect, thus providing a valuable reference for understanding the potential benefits of natural BPs in treating metabolic diseases. These properties make BPs promising agents for preventing and treating metabolic diseases. The comprehensive understanding of the mechanisms by which BPs exert their effects through gut microbiota opens new avenues for developing targeted therapies to improve metabolic health.

Distinctive activation of β-galactosidase by carboxymethylated β-glucan in vitro and mechanism study: Critical role of hydrophobic and electrostatic interactions

β-galactosidase (lactase) is commercially important as a dietary supplement to alleviate the symptoms of lactose intolerance. This work investigated a unique activation of CMP (carboxymethylated (1 → 3)-β-d-glucan) on lactase and its mechanism by comparing it with carboxymethyl chitosan (CMCS), an inhibitor of lactase. The results illustrated that the secondary and tertiary structures of lactase were altered and its active sites exposed after complexation with CMP, and dissociation of lactase aggregates was also observed. These changes favored better accessibility of the substrate to the active sites of lactase, resulting in a maximum increase of 60.5 % in lactase activity. Furthermore, the hydrophobic and electrostatic interactions with lactase caused by the carboxymethyl group of CMP were shown to be crucial for its activation ability. Thus, the improvement of lactase activity and stability by CMP shown here is important for the development of new products in the food and pharmaceutical industries.

Effects of Different Drying Methods on the Structural Characteristics and Multiple Bioactivities of Rosa roxburghii Tratt Fruit Polysaccharides

Drying conditions significantly impact the compositions and microstructures of polysaccharides, leading to various effects on their chemical characteristics and bioactivities. The objective of this study was to investigate how different industrial drying techniques, i.e., hot air drying, infrared drying, microwave vacuum drying, and freeze drying, affect the structural properties and biological activities of polysaccharides extracted from Rosa roxburghii Tratt fruit (RRTP). Results revealed that these drying methods significantly altered the extraction yield, molecular weights, monosaccharide ratios, contents of uronic acid and total sugars, gelling properties, particle sizes, thermal stability, and microstructures of RRTPs. However, the monosaccharide composition and functional groups of polysaccharides remained consistent across the different drying techniques. Biological activity assays demonstrated that RRTPs, particularly those processed through microwave vacuum drying (MVD-RRTP), exhibited excellent anti-linoleic acid oxidation, robust anti-glycosylation effects, and significant α-glucosidase inhibition in vitro. The outcomes of this research demonstrate that microwave vacuum drying serves as an effective pre-extraction drying method for RRTPs, enhancing their biological activities. This technique is particularly advantageous for preparing RRTPs intended for use in functional foods and pharmaceuticals, optimizing their health-promoting properties for industrial applications.

Preparation, characterization and evaluation of microwave-assisted synthesized selenylation Codonopsis pilosula polysaccharides

In this work, the selenylation Codonopsis pilosula polysaccharide (Se-CPPS) were synthesized using an optimized microwave-assisted method. Then, physicochemical properties, including molecular weight, particle size, valence state of selenium, antioxidant capacity, release mechanism of selenium under gastrointestinal conditions, as well as their effects on HT-29 cell viability were comprehensively investigated. The results demonstrated that Se-CPPS with the highest selenium content (21.71 mg/g) was synthesized using 0.8% nitric acid concentration under microwave conditions of 90 min at 70 °C. FTIR and XPS analysis revealed that Se was bound to the polysaccharide chain in the form of O-Se-O and O-H···Se, with a valence state of either 0 or +4. In vitro investigations on antioxidant activity and selenium release capacity indicated that selenization not only enhanced the antioxidant activity of CPPS but also endowed Se-CPPS with robust selenium release capability in simulated gastric digestion. The effects of Se-CPPS on HT-29 cells was further investigated by CCK-8 method. The results showed that the selenide modification effectively reduced the toxicity of Na2SeO3 and enhanced the viability of CPPS. The findings of this study offer valuable methodological guidance for the synthesis of Se-polysaccharides with superior functional properties.

Se-rich tea polysaccharide extracted by high hydrostatic pressure attenuated anaphylaxis by improving gut microbiota and metabolic regulation

Selenium-rich tea polysaccharides (Se-TPS) were extracted via high hydrostatic pressure technology with a pressure of 400 MPa (200-500 MPa) for 10 min (3-20 min) at a material-to-solvent ratio of 1:40 (1:20-1:50). Subsequently, Se-TPS1-4 were isolated and purified, with Se-TPS3-4 as the main components. A spectral analysis proved that Se, which has antioxidant activity, existed. An in vitro study found that among Se-TPS, Se-TPS3-4 attenuated the release of β-hexosaminidase, histamine, and interleukin (IL)-4. Furthermore, in vivo experiments revealed that treatment with Se-TPS downregulated IL-4 levels and upregulated TGF-β and interferon-γ levels to improve imbalanced Th1/Th2 immunity in tropomyosin-sensitized mice. Moreover, Se-TPS promoted Lactobacillus and norank_f_Muribaculaceaek growth and upregulated metabolites such as genipin and coniferyl alcohol. Overall, these results showed the strong anti-allergy potential of Se-TPS by regulating mast cell-mediated allergic inflammatory responses and microbiota regulation, highlighting the potential of Se-TPS as a novel therapeutic agent to regulate allergy-associated metabolic disorders.

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.

Ultrasonic-Assisted Decoloration of Polysaccharides from Seedless Chestnut Rose (Rosa sterilis) Fruit: Insight into the Impact of Different Macroporous Resins on Its Structural Characterization and In Vitro Hypoglycemic Activity

Pigments within polysaccharides pose significant challenges when analyzing their structural characteristics and evaluating their biological activities, making decolorization a crucial step in purifying these biomolecules. In this research, a novel approach using ultrasound-assisted static adsorption with macroporous resins was employed to decolorize polysaccharides extracted from seedless chestnut rose (Rosa sterilis S. D. Shi) fruit (RSP). Among the fourteen tested resins, AB-8, D101, D4020, HPD100, and S8 were identified as the most effective, demonstrating superior decoloration efficiency and polysaccharide recovery. Further examinations of RSPs treated with these five resins revealed distinct effects on their uronic acid levels, monosaccharide makeup, molecular weight, surface structure, and hypoglycemic properties. The RSP treated with HPD100 resin stood out for having the highest uronic acid content, smallest particle size, and lowest molecular weight, leading to the most notable inhibition of α-glucosidase activity through a mixed inhibition model. The application of HPD100 resin in the decolorization process not only potentially preserved the macromolecular structure of RSP but also enhanced its hypoglycemic efficacy. These findings provide a solid theoretical basis for further exploring RSP as a component of functional foods, underscoring the effectiveness of the ultrasound-assisted resin adsorption method in polysaccharide purification.

Preparation and Characterization of a Hypoglycemic Complex of Gallic Acid-Antarctic Krill Polypeptide Based on Polylactic Acid-Hydroxyacetic Acid (PLGA) and High-Pressure Microjet Microencapsulation

Gallic acid-Antarctic krill peptides (GA-AKP) nanocapsules (GA-AKP-Ns) were prepared using a dual delivery system with complex emulsion as the technical method, a high-pressure microjet as the technical means, polylactic acid-hydroxyacetic acid (PLGA) as the drug delivery vehicle, and GA-AKP as the raw material for delivery. This study aimed to investigate the effects of microjet treatment and the concentration of PLGA on the physicochemical properties and stability of the emulsion. Under optimal conditions, the physicochemical properties and hypoglycemic function of nano-microcapsules prepared after lyophilization by the solvent evaporation method were analyzed. Through the microjet treatment, the particle size of the emulsion was reduced, the stability of the emulsion was improved, and the encapsulation rate of GA-AKP was increased. The PLGA at low concentrations decreased the particle size of the emulsion, while PLGA at high concentrations enhanced the encapsulation efficiency of the emulsion. Additionally, favorable results were obtained for emulsion preparation through high-pressure microjet treatment. After three treatment cycles with a PLGA concentration of 20 mg/mL and a microjet pressure of 150 MPa (manometric pressure), the emulsion displayed the smallest particle size (285.1 ± 3.0 nm), the highest encapsulation rates of GA (71.5%) and AKP (85.2%), and optimal physical stability. GA-AKP was uniformly embedded in capsules, which can be slowly released in in vitro environments, and effectively inhibited α-amylase, α-glucosidase, and DPP-IV at different storage temperatures. This study demonstrated that PLGA as a carrier combined with microjet technology can produce excellent microcapsules, especially nano-microcapsules, and these microcapsules effectively improve the bioavailability and effectiveness of bioactive ingredients.

Preparation, characterization and cytotoxicity assessment of a novel selenized polysaccharide from Morchella sextelata

Selenylation modification has been widely developed to improve the biological effects of natural polysaccharides. In this study, a purified new polysaccharide (MSP-4) was isolated from Morchella Sextelata, and selenized into SeMSP-4 using the HNO3-Na2SeO3 method. The selenium (Se) content of SeMSP-4 was 101.81 ± 9.90 mg/kg, and the molecular weight of SeMSP-4 was 1.23 × 105 Da. The FT-IR, XRD and AFM results showed that MSP-4 was successfully combined with the Se element. The structure characters of SeMSP-4 were analyzed by methylation analysis combined with 1D and 2D NMR spectroscopy. And, the radical scavenging test revealed that SeMSP-4 exhibited higher antioxidant capacities in vitro than MSP-4. The cytotoxicity analysis indicated that SeMSP-4 could dose-dependently inhibit the proliferation of HepG2 and HeLa cells, but did not show a cytotoxic effect on normal cells (HEK293). Furthermore, SeMSP-4 stimulation significantly increased the macrophage viability and enhanced NO production in macrophage cells. This study suggested that SeMSP-4 could be utilized as a potential selenium source with antioxidant, antitumor, and immunostimulatory activities.

Effect of Fucoidan on Structure and Bioactivity of Chinese Steamed Bread

Fucoidan refers to a group of sulphated polysaccharides obtained from brown seaweed, with numerous biological activities. In this study, fucoidan was fortified into Chinese steamed bread (CSB) at different concentrations (0, 1%, 3% and 5%) and the effect of fucoidan on the dough properties, structure properties and bioactivity were investigated. The results showed that fucoidan could change the viscosity of unfermented dough, and a high concentration of fucoidan could remove the free radicals produced by the SH-SS exchange reaction (GS-) in the dough, which significantly reduced the content of disulfide bond and reduced the expanded volume of fermented dough (p < 0.05). In addition, fucoidan forms a physical barrier on the surface of starch particles and hinders the reaction between protein-to-protein; therefore, fucoidan increased the hardness, gumminess and chewiness in CSB, and reduced the specific volume in CSB. Furthermore, the fucoidan-fortified CSB samples were found to have both the ability to significantly reduce the predicted glycemic index (pGI) (p < 0.05) and improve antioxidant activity (p < 0.05). Collectively, these findings could provide a theoretical basis for the applications of fucoidan as a functional component in fermented foods.

Comparative Study on the Impact of Different Extraction Technologies on Structural Characteristics, Physicochemical Properties, and Biological Activities of Polysaccharides from Seedless Chestnut Rose (Rosa sterilis) Fruit

Seedless chestnut rose (Rosa sterilis S. D. Shi, RS) is a fresh type of R. roxburghii Tratt with copious functional components in its fruit. Polysaccharides are recognized as one of the vital bioactive compounds in RS fruits, but their antioxidant and hypoglycemic properties have not been extensively explored. Hence, in this study, accelerated solvent extraction (RSP-W), citric acid (RSP-C), 5% sodium hydroxide/0.05% sodium borohydride (RSP-A), and 0.9% sodium chloride (RSP-S) solution extraction were individually utilized to obtain RS fruit polysaccharides. The physicochemical properties, structural characteristics, and biological activities were then compared. Results indicated that extraction methods had significant influences on the extraction yield, uronic acid content, monosaccharide composition, molecular weight, particle size, thermal stability, triple-helical structure, and surface morphology of RSPs apart from the major linkage bands and crystalline characteristics. The bioactivity tests showed that the RSP-S, which had the greatest amount of uronic acid and a comparatively lower molecular weight, exhibited more potent antioxidant and α-glucosidase inhibitory property. Furthermore, all RSPs inhibited α-glucosidase through a mixed-type manner and quenched their fluorescence predominantly via a static quenching mechanism, with RSP-S showing the highest binding efficiency. Our findings provide a theoretical basis for utilizing RSPs as functional ingredients in food industries.

Extraction and characterization of polysaccharides from blackcurrant fruits and its inhibitory effects on acetylcholinesterase

Microwave assisted aqueous two-phase system (MA-ATPS) was used to simultaneously extract two polysaccharides from blackcurrant. Under the suitable ATPS (ethanol/(NH4)2SO4, 26.75 %/18.98 %) combining with the optimal MA conditions (liquid-to-material ratio 58.5 mL/g, time 9.5 min, temperature 60.5 °C, power 587 W) predicted by response surface methodology, the yields of the top/bottom phase polysaccharides were 13.08 ± 0.37 % and 42.65 ± 0.89 %, respectively. After purification through column chromatography, the top phase polysaccharide (PRTP) and bottom phase polysaccharide (PRBP) were obtained. FT-IR, methylation and NMR analyses confirmed that the repeating unit in the backbone of PRTP was →2, 5)-α-L-Araf-(1 → 3)-α-D-Manp-(1 → 6)-β-D-Galp-(1 → 6)-α-D-Glcp-(1 → 4)-α-L-Rhap-(1 → 4)-α-D-GalAp-(1→, while the possible unit in PRBP was →4)-α-L-Rhap-(1 → 3)-α-D-Manp-(1 → 6)-β-D-Galp-(1 → 6)-α-D-Glcp-(1 → 2, 5)-α-L-Araf-(1 → 4)-α-D-GalAp-(1→. PRBP with relatively low molecular weight exhibited better stability, rheological property, free radical scavenging and acetylcholinesterase (AChE) inhibitory activities than PRTP. PRTP and PRBP were reversible mixed-type inhibitors for AChE, and the conformation of AChE was changed after binding with the polysaccharides. Molecular docking, fluorescence and isothermal titration calorimetry assays revealed that PRTP and PRBP quenched the fluorescence through static quenching mechanism, and the van der Waals interactions and hydrogen bonding played key roles in the stability of polysaccharide-enzyme complexes. This study provided a theoretical basis for blackcurrant polysaccharides as AChE inhibitors to treat Alzheimer's disease.

Microwave-assisted aqueous two-phase extraction of polysaccharides from Hippophae rhamnoide L.: Modeling, characterization and hypoglycemic activity

Natural polysaccharides are concerned for their high biological activity and low toxicity. Two kinds of polysaccharides were extracted from Hippophae rhamnoide L. by microwave-assisted aqueous two-phase system. Under the optimal conditions predicted by RSM model (K2HPO4/ethanol (18.93 %/28.29 %), liquid to material ratio 77 mL/g, power 625 W and temperature 61 °C), the yield of total polysaccharides reached 35.91 ± 0.76 %. Moreover, the polysaccharides extraction was well fitted to the Weibull model. After purification by Sepharose-6B, the polysaccharides from top phase (PHTP, purity of 81.44 ± 1.25 %) and bottom phase (PHBP, purity of 88.85 ± 1.40 %) were obtained. GC, FT-IR, methylation and NMR analyses confirmed the backbone of PHTP was composed of a repeated unit →4)-β-D-Glcp-(1 → 2)-α-L-Rhap-(1 → 4)-β-D-Galp-(1 → 4)-α-D-GalAp-(1 → 3)-α-L-Araf-(1 → 3)-α-D-Manp-(1→, while the repeated unit in PHBP was →3)-α-L-Araf-(1 → 2)-α-L-Rhap-(1 → 4)-β-D-Glcp-(1 → 3)-α-D-Manp-(1 → 4)-β-D-Galp-(1 → 4)-α-D-GalAp-(1→. Compared with PHTP (6.46 × 106 g/mol), PHBP with relatively low molecular weight (8.2 × 105 g/mol) exhibited the smaller particle size, better water-solubility, thermal and rheological property, stronger anti-glycosylation and α-amylase inhibitory effects. Moreover, PHTP and PHBP displayed a reversible inhibition on α-amylase in a competitive manner. This study provides a high-efficient and eco-friendly method for polysaccharides extraction, and lays a foundation for sea buckthorn polysaccharides as potential therapeutic agents in preventing and ameliorating diabetes.

Natural antibacterial membranes prepared using Schisandra chinensis extracts and polyvinyl alcohol in an environment-friendly manner

Foodborne pathogens can cause food spoilage and lead to food safety issues. In recent years, food packaging has received a lot of attention. Traditional packaging membranes are non-biodegradable and remain in the environment for a long time. In this study, natural antimicrobial substances were extracted from Schisandra chinensis by a green extraction process using distilled water as the solvent, and the effects of different treatment on the antimicrobial activity of the extract were compared. At the same time, four types of Schisandra chinensis antimicrobial membranes were prepared using polyvinyl alcohol (PVA) as the substrate. The whole extraction and membrane preparation process did not involve organic solvents, making the process green and environment friendly. Material characterization included inverted biological microscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FTIR), tensile strength test, pore size measurement, water uptake test, etc. Among them, no extract particles were observed with the naked eye on the surfaces of MⅡ and MⅣ. MⅡ has a uniformly transparent, nearly colorless morphology and is the most tensile. MⅣ surface is flat and smooth, the microstructure is dense and uniform. At the same time, the four types of membranes were tested against common pathogenic bacteria for 12 h, and the OD600 trend revealed the excellent antimicrobial activity of the membranes against S. aureus, MRSA, E. coli, and L. monocytogenes. The membranes could also be reused at least once. This study provides a new idea for preparing natural plant-based antimicrobial membranes.

Preparation of Ribes nigrum L. polysaccharides-stabilized selenium nanoparticles for enhancement of the anti-glycation and α-glucosidase inhibitory activities

Seven kinds of selenium nanoparticles (RP-SeNPs) were prepared by using the polysaccharides extracted from Ribes nigrum L. (RP) as the stabilizer and dispersant. Among them, RP-SeNPs-1 (94.2 nm), RP-SeNPs-2 (101.2 nm) and RP-SeNPs-3 (107.6 nm) with relatively smaller mean particle size exhibited stronger α-glucosidase inhibitory activity than other RP-SeNPs (115.3-164.2 nm) and SeNPs (288.9 nm). Ultraviolet-visible spectrophotometry, Fourier transform-infrared, X-ray diffraction, energy dispersive X-ray and X-ray photoelectron spectroscopy analyses confirmed that SeNPs were ligated with RP to form nanocomposites and displayed amorphous form. Electron microscopy images revealed that RP-SeNPs-1 - RP-SeNPs-3 were regular shape spherical nanocomposites with much better dispersion than SeNPs. Compared with SeNPs, RP-SeNPs displayed relatively high thermal, storage, pH and salt ion stability. Moreover, RP-SeNPs-1-RP-SeNPs-3 showed significantly better anti-glycation and α-glucosidase inhibitory activity than SeNPs, especially RP-SeNPs-1 with the smallest particle size. Inhibitory kinetics analysis indicated that SeNPs and RP-SeNPs inhibited α-glucosidase with competitive type and reversible mechanism. In addition, the conformation of the α-glucosidase was changed after binding with the SeNPs and RP-SeNPs-1. Fluorescence quenching and isothermal titration calorimetry assays revealed that these two nanoparticles could interact with α-glucosidase to form non-fluorescent complexes through hydrogen bonding, and the formation was spontaneously driven by enthalpy.

Protective Effects of Different Selenium Green Tea Polysaccharides on the Development of Type 2 Diabetes in Mice

Selenium polysaccharides have attracted significant interest due to their superior function to that of individual polysaccharides. However, limited research has compared the protective effects of different selenium polysaccharides from different selenization methods on diabetes. This work aims to compare the preventive effects of natural selenium-enriched green tea polysaccharides (NSe-TPS), synthetic selenized green tea polysaccharides (PCSe-TPS), and a mixture of sodium selenite and green tea polysaccharides (ordinary tea polysaccharides (Ord-TPS)+Se) on the development of diabetes. While establishing a diabetes model induced by a high-sugar, high-fat diet combined with streptozotocin, different selenium polysaccharides were administered daily by gavage for nine weeks. Our findings indicate that PCSe-TPS exhibited superior preventive effects on developing type 2 diabetes compared to NSe-TPS and Ord-TPS+Se. PCSe-TPS effectively regulated glucose metabolism and insulin resistance by activating the PI3K/Akt pathway, thereby preventing elevated blood glucose levels. Additionally, PCSe-TPS mitigated oxidative damage and inflammatory responses in liver tissues. Notably, PCSe-TPS intervention reversed the decline in bacterial species richness and the abundance of unclassified_Oscillospiraceae during the development of diabetes in mice. These results provide valuable insights into the protective effects of PCSe-TPS against diabetes development, highlighting its advantages over NSe-TPS and Ord-TPS+Se.

Shiitake polysaccharides acted as a non-competitive inhibitor to α-glucosidase and inhibited glucose transport of digested starch from Caco-2 cells monolayer

The inhibition mechanism of shitake mushroom polysaccharides (Lentinula edodes polysaccharides, LEP) against α-glucosidase was studied by enzyme kinetic assay, fluorescence quenching and molecular docking. The effect of LEP on glucose transport of digested starch was investigated via an in vitro digestion/Caco-2 transwell model. LEP exhibited a stronger inhibiting effect (IC50 = 0.66 mg/mL) than acarbose and presented a non-competitive inhibition mechanism. The interaction between LEP and α-glucosidase primarily involved electrostatic interaction and hydrogen bonding. Molecular docking modelling showed that the four structures of LEP were bound to the allosteric tunnel or adjacent pocket of α-glucosidase via electrostatic force and hydrogen bonds. The (1 → 6)-linkages in LEP structures favoured its binding affinity to the α-glucosidase. The α-glucosidase inhibiting activity of LEP was also found to emanate from the reduction in glucose transport of digested starch as deducted from the in vitro digestion/Caco-2 transwell data. The release of glucose from digested starch cooked with LEP was significantly reduced (33.7%) compared to the digested starch without LEP. The findings from the current study suggest that LEP could be a promising ingredient to inhibit α-glucosidase activity as well as control the level of postprandial blood glucose when incorporated into starchy foods.

Optimization of ultrasonic-assisted extraction of Platycodon grandiflorum polysaccharides and evaluation of its structural, antioxidant and hypoglycemic activity

The study aimed to improve the extraction rate of Platycodon grandiflorum roots polysaccharides (PGPs) using ultrasound-assisted extraction (UAE). A comparative analysis was undertaken to evaluate polysaccharides content, molecular weight distribution, monosaccharide composition, preliminary structure, antioxidant, and hypoglycemic activity of UAE in comparison with heating water extraction (HWE). The optimum extraction conditions included a liquid-to-material ratio of 20 mL/g, ultrasonic power of 150 W, extraction temperature of 70 ℃, and extraction time of 20 min, resulting in a significantly greater polysaccharides (12.011 ± 0.91 %) compared to HWE (7.62 ± 0.18 %). Through Sephacryl S-100 column elution, two homogenous fraction (PGP-U extracted with UAE and PGP-H extracted with HAE) were obtained. The molecular weight of PGP-U and PGP-H was 3.14 kDa and 3.44 kDa, respectively, mainly composed of different proportions of fourteen monosaccharides. Fourier transform infrared spectroscopy (FT-IR) and Nuclear Magnetic Resonance (NMR) spectra experiment results showed that the two polysaccharides were pyranose ring with α- and β-glycoside bond. PGP-U and PGP-H exhibited specific antioxidant activities, encompassing total reducing force, scavenging of DPPH radicals, ABTs radicals and hydroxyl radicals in vitro, along with mitigation of H2O2-induced damage in HepG2 cells. Moreover, PGP-U exerted significantly stronger inhibitory activities against α-amylase and α-glucosidase and could significantly enhances the glucose uptake capacity and intracellular glycogen content of insulin-resistant HepG2 (IR-HepG2) cells.

Selenium Modification of Natural Products and Its Research Progress

The selenization of natural products refers to the chemical modification method of artificially introducing selenium atoms into natural products to interact with the functional groups in the target molecule to form selenides. Nowadays, even though scientists in fields involving organic selenium compounds have achieved numerous results due to their continuous investment, few comprehensive and systematic summaries relating to their research results can be found. The present paper summarizes the selenization modification methods of several kinds of important natural products, such as polysaccharides, proteins/polypeptides, polyphenols, lipids, and cyclic compounds, as well as the basic principles or mechanisms of the selenizing methods. On this basis, this paper explored the future development trend of the research field relating to selenized natural products, and it is hoped to provide some suggestions for directional selenization modification and the application of natural active ingredients.

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.

Acidic polysaccharides from black ear and silver ear mushrooms modulated the release and transport of glucose from gelatinised sorghum starch during digestion

This study investigated the ability of acidic polysaccharides from Auricularia auricula-judae (AAP) and Tremella fuciformis (TFP) mushrooms to modulate starch digestion and absorption. Gelatinised sorghum starch was used as starch-rich material, and its digestion and glucose transport were determined through in vitro digestion/Caco-2 cells model. Results showed that fortification with 0.6% AAP/TFP increased the proportion of high molecular weight α-dextrin and delayed glucose diffusion from digested starch gels. Gelatinisation of sorghum starch with AAP and TFP reduced the amount of transported glucose by 34.2% and 38.7%, respectively. This reduction was related to the inhibition of AAP/TFP on α-glucosidase and the difficulty in the hydrolysis of high molecular weight maltooligosaccharides. The potential bonding of AAP/TFP to glucose transporter (SGLT1) also impeded glucose transport. The findings suggest that AAP/TFP could act as natural hypoglycaemic agents used in starch-based foods and provide a better understanding of the hypoglycaemic mechanism of mushroom polysaccharides.

Characterization of manganized soluble dietary fiber complexes from tigernut meal and study of the suppressive activity of digestive enzymes in vitro

In this study, manganized soluble dietary fiber (SDF-Mn(II)) was prepared from tigernut meal using a microwave solid-phase synthesis method with SDF. Microscopic morphological and structural analyses of SDF-Mn(II) were carried out using scanning electron microscopy, Fourier infrared spectroscopy, UV full-band scanning, X-ray diffraction, a thermal analyzer, gel permeation chromatography, and nuclear magnetic resonance, and its in vitro hypoglycemic activity was initially investigated. The results of these analyses revealed that the reaction of Mn(II) with SDF mainly involved hydroxyl and carbonyl groups, with the Nuclear magnetic resonance (NMR) analysis showing that specific covalent binding was produced and substitution was mainly carried out at the C₆ position. Moreover, compared with SDF, the SDF-Mn(II) complex exhibited a porous structure, red-shifted, and color-enhancing effects on the UV characteristic peaks, significantly increased crystallinity and decreased molecular weight, and improved thermal stability; in addition, SDF-Mn(II) afforded significantly enhanced inhibition of α-amylase and α-glucosidase and possesses good in vitro digestive enzyme inhibition activity.

High-throughput screening and investigation of the inhibitory mechanism of α-glucosidase inhibitors in teas using an affinity selection-mass spectrometry method

An affinity selection-mass spectrometry method was applied for high-throughput screening of α-glucosidase (AGH) inhibitors from teas. Fourteen out of nineteen screened AGH inhibitor candidates were clustered as galloylated polyphenols (GPs). "AGH-GPs" interaction studies, including enzyme kinetics, fluorescence spectroscopy, circular dichroism, and molecular docking, jointly suggested that GPs noncompetitively inhibit AGH activity by interacting with amino acid residues near the active site of AGH and inducing changes in AGH secondary structure. Representative GPs and white tea extract (WTE) showed comparable AGH inhibition effects in Caco2 cells and postprandial hypoglycemic efficacy in diabetic mice as acarbose. The area under the curve of oral sucrose tolerance test was lower by 8.16%, 6.17%, and 7.37% than control group in 15 mg/kg EGCG, 15 mg/kg strictinin, and 150 mg/kg WTE group, respectively. Our study presents a high-efficiency approach to discover novel AGH inhibitors and elucidates a potential mechanism by which tea decreases diabetes risks.

Structural Characterization, In Vitro Digestion Property, and Biological Activity of Sweet Corn Cob Polysaccharide Iron (III) Complexes

This study aimed to enhance the utilization value of sweet corn cob, an agricultural cereal byproduct. Sweet corn cob polysaccharide-ron (III) complexes were prepared at four different temperatures (40 °C, 50 °C, 60 °C, and 70 °C). It was demonstrated that the complexes prepared at different temperatures were successfully bound to iron (III), and there was no significant difference in chemical composition; and SCCP-Fe-C demonstrated the highest iron content. The structural characterization suggested that sweet corn cob polysaccharide (SCCP) formed stable β-FeOOH iron nuclei with −OH and −OOH. All the four complexes’ thermal stability was enhanced, especially in SCCP-Fe-C. In vitro iron (III) release experiments revealed that all four complexes were rapidly released and acted as iron (III) supplements. Moreover, in vitro antioxidant, α-glucosidase, and α-amylase inhibition studies revealed that the biological activities of all four complexes were enhanced compared with those of SCCP. SCCP-Fe-B and SCCP-Fe-C exhibited the highest in vitro antioxidant, α-glucosidase, and α-amylase inhibition abilities. This study will suggest using sweet corn cobs, a natural agricultural cereal byproduct, in functional foods. Furthermore, we proposed that the complexes prepared from agricultural byproducts can be used as a potential iron supplement.

Physicochemical properties and in vitro hypoglycemic activities of hsian-tsao polysaccharide fractions by gradient ethanol precipitation method

Hsian-tsao polysaccharides fractions (HPs), including HP20, HP40, HP60, and HP80, were fractioned by gradient precipitation of 20 %, 40 %, 60 %, and 80 % (v/v) ethanol, respectively. Their physicochemical properties and in vitro hypoglycemic activities (inhibitory activities on α-amylase and α-glucosidase, glucose adsorption capacity, and glucose diffusion retardation) were determined. The results showed that, with ethanol upward, the average particle size, molecular weight, and apparent viscosity of HPs were decreased while carbohydrate and uronic acid contents, absolute zeta potential, and thermal stability were increased. Each of the HPs contained Rha, Ara, Gal, Xyl, Man, and GalA with different molar ratios, indicative of anionic heteropolysaccharides with uronic acid. HPs, with diverse structures and surface morphologies as proved by FTIR and SEM, whose solutions were pseudoplastic fluids, exhibited elastic behavior of weak gel networks at concentrations of >1 %. Moreover, HPs showed inhibitory activities on α-amylase and α-glucosidase, of which HP80 was the strongest. For α-amylase, HP20 and HP60 behaved as mixed inhibitors, while HP40 and HP80 were non-competitive. For α-glucosidase, HPs acted as mixed inhibitors. Additionally, HPs possessed glucose adsorption capacity and glucose diffusion retardation, with the best for HP20. These results suggested that HPs possessed hypoglycemic activities, which could be developed as functional food or hypoglycemic drugs.

Ultrasonic Treatment Enhances the Antioxidant and Immune-Stimulatory Properties of the Polysaccharide from Sinopodophyllum hexandrum Fruit

We aimed to assess the potential of ultrasonic treatment on the processing of polysaccharides as functional foods or food additives. The polysaccharide from Sinopodophyllum hexandrum fruit (SHP, 52.46 kDa, 1.91 nm) was isolated and purified. SHP was treated with various levels of ultrasound (250 W and 500 W), resulting in the formation of two polysaccharides, SHP1 (29.37 kD, 1.40 nm) and SHP2 (36.91 kDa, 0.987 nm). Ultrasonic treatment was found to reduce the surface roughness and molecular weight of the polysaccharides, leading to thinning and fracturing. The effect of ultrasonic treatment on polysaccharide activity was evaluated in vitro and in vivo. In vivo experiments showed that ultrasonic treatment improved the organ index. Simultaneously, it enhanced the activity of superoxide dismutase, total antioxidant capacity, and decreased the content of malondialdehyde in the liver. In vitro experiments demonstrated that ultrasonic treatment also promoted proliferation, nitric oxide secretion, phagocytic efficiency, costimulatory factors (CD80+, CD86+) expression, and cytokine(IL-6, IL-1β) production of RAW264.7 macrophages.

Design, synthesis, spectroscopic characterizations, antidiabetic, in silico and kinetic evaluation of novel curcumin-fused aldohexoses

Curcumin (bis-α,β-unsaturated β-diketone) plays an important role in the prevention of numerous diseases, including diabetes. Curcumin, as an enzyme inhibitor, has ideal structural properties including hydrophobic nature, flexible backbone, and several available hydrogen bond (H-bond) donors and acceptors. In this study, curcumin-fused aldohexose derivatives 3(a-c) were synthesized and used as influential agents in the treatment of diabetes with inhibitory properties against two carbohydrate-hydrolyzing enzymes α-glucosidase (α-Gls) and α-amylase (α-Amy) which are known to be significant therapeutic targets for the reduction of postprandial hyperglycemia. These compounds were isolated, purified, and then spectrally characterized via FT-IR, Mass, 1H, and 13C NMR, which strongly confirmed the targeted product's formation. Also, their inhibitory properties against α-Gls and α-Amy were evaluated spectroscopically. The Results indicated that all compounds strongly inhibited α-Amy and α-Gls by mixed and competitive mechanisms, respectively. The intrinsic fluorescence of α-Amy was quenched by the interaction with compounds 1 and 3b through a dynamic quenching mechanism, and the 1 and 3b/α-Amy complexes were spontaneously formed, mainly driven by the hydrophobic interaction and hydrogen bonding. Fourier transform infrared spectra (FT-IR) comprehensively verified that the binding of compounds 1 and 3b to α-Amy would change the conformation and microenvironment of α-Amy, thereby inhibiting the enzyme activity. Docking and molecular dynamics (MD) simulations showed that all compounds interacted with amino acid residues located in the active pocket site of the proteins. In vivo studies confirmed the plasma glucose diminution after the administration of compound 3b to Wistar rats. Accordingly, the results of the current work may prompt the scientific communities to investigate the possibility of compound 3b application in the clinic.