Physicochemical properties and structural characterization of a galactomannan from Sophora alopecuroides L. seeds

Unveiling side-chain architectures of corn husk hemicellulose to drive enzyme cocktail design for degradation of biomass

By analyzing residual hemicellulose after enzymatic hydrolysis of corn husks, we identified previously unreported side-chain architectures in glucuronoarabinoxylan and xyloglucan of corn husk hemicellulose, including α-galactosyl-mannose and α-xylosyl-arabinose linkages, which shield glycosidic bonds from enzymatic cleavage. These discoveries unveil novel structural complexes in hemicellulose and broaden the understanding of hemicellulose recalcitrance beyond existing literature. Further, we designed a tailored enzyme cocktail by heterologously expressing three targeted hemicellulases (GH51 α-L-arabinofuranosidase, GH27 α-D-galactosidase, and GH31 α-D-xylosidase) based on hemicellulose structural information, and synergistic integration of these enzymes with Penicillium oxalicum cellulase via response surface optimization. This enzyme system achieved unprecedented yields of 81.82 % glucose and 54.89 % arabinose through one-step hydrolysis without chemical pretreatment, surpassing previous benchmarks by over 30 %. This study advances the understanding of hemicellulose's intricate structural complexity and enhances insights into multi-enzyme synergies during biomass degradation, offering a pivotal framework for developing pretreatment-free, eco-friendly enzymatic hydrolysis processes and enabling high-value utilization of corn husks.

Structural characterization and chondroprotective activity evaluation of four novel polysaccharides purified from Anoectochilus zhejiangensis on transgenic fluorescent zebrafish

Anoectochilus zhejiangensis (AZJ) exhibits notable anti-inflammatory and anti-swelling properties, making it a potential therapeutic agent for osteoarthritis. However, the specific component responsible for its anti-osteoarthritis effects remains unidentified. In this study, four novel polysaccharides were purified from Anoectochilus zhejiangensis (i.e., AZJP-1a, AZJP-2a, AZJP-2b, and AZJP-2c) through DEAE-cellulose 52 and Sephadex G-200 column chromatographic separation. Their structural and conformational characteristics were comprehensively analyzed. AZJP-1a and AZJP-2a owned high molecular weights of 387 kDa and 947 kDa, while AZJP-2b and AZJP-2c were comparatively lower at 3.989 kDa and 3.045 kDa. The polysaccharides contained predominantly β-glycosidic linkages over α-glycosidic linkages. AZJP-1a primarily consists of mannose, while AZJP-2a and AZJP-2b are rich in glucose, galactose, and arabinose, and AZJP-2c is mainly composed of glucose. Chondroprotective effects of these polysaccharides were evaluated using fluorescence imaging in transgenic fluorescent zebrafish (Tg Col2a1a: eGFP), with all four polysaccharides demonstrating significant cartilage repair activity, surpassing that of the positive control drug alendronate. Among them, AZJP-2c exhibited the most potent effect. The observed variations in their biological activities are likely attributed to differences in their structural compositions.

Effect of triple helix polysaccharides from foxtail millet bran on millet starch gel formation

Polysaccharides as modifiers can solve native starch gel problem of weaker gel strength and lower gelation trend. The key structures of foxtail millet bran polysaccharides (FMBPs) in improving millet starch gel properties were investigated. Results showed that FMBPs were high molecular weight (Mw) heteropolysaccharides and the distribution of total sugar, uronic acid and monosaccharides was non-uniform in four FMBPs. Structural analysis revealed triple helix polysaccharides (THPs) existed in independent triple helix (ITH) and aggregates forms. The redshift degree of Congo red-FMBP complexes illustrated that FMBP-S1 contain the most ITHs, followed by FMBP-S2 and FMBP-S4, and the least in FMBP-S3. The porous structure of FMBPs promoted the adsorption of Congo red, bringing about the increase in weight and volume of the complexes and eventual precipitation. Separation of THPs provided a new method to investigate its role in starch gel. The results showed FMBPs with more ITHs showed higher peak viscosity, breakdown and setback. The presence of ITHs could reduce gel point temperature (ΔT = 6.62-29.86 °C) and water holding capacity (from 50 to 66 ms to 231 ms), but improve the viscoelasticity of gel. The study not only improved the quality of starch-based gel but also achieved high-value utilization of foxtail millet bran.

Determination of physicochemical, functional,and morphological properties of Prosopis farcta (Çeti̇) seed galactomannan as a new hydrocolloid source: Comparison with locust bean gum

The present study investigated the properties of galactomannan, a water-soluble polysaccharide extracted from the Prosopis farcta (Çeti) plant. These properties encompassed its functional characteristics, chemical composition, rheological behavior, and morphological structure. The results were systematically compared with those of the commercially utilized locust bean gum (LBG). Following ethanol precipitation, the yield of Prosopis farcta galactomannan (PFG) was determined to be 22.4 ± 0.5 %. The mannose-to-galactose (M: G) ratios of PFG and LBG were calculated as 1.7:1 and 3.3:1, respectively. The solubility of PFG exhibited a temperature-dependent increase akin to that of LBG. Notably, PFG demonstrated superior emulsion capacity and stability even at low concentrations. Additionally, the X-ray diffraction (XRD) analysis revealed asymmetric broad peaks around the 2θ = 20° diffraction angle, signifying the amorphous nature of PFG. Scanning electron microscopy (SEM) images, obtained after dissolving both PFG and LBG in deionized water and freeze-drying them, displayed a fibrous filament network structure in both samples.

Structural characterization of an apple polysaccharide and its anti-inflammatory effect through suppressing TLR4/NF-κB signaling

The current study isolated a homogeneous polysaccharide (AP) with a molecular weight of 7.9 kDa from the pomace of Fuji apples. AP was found to consists of rhamnose, galactose, arabinose, glucose, and galacturonic acid in a ratio of 4.3:5.2:2.6:1.0:11.9. Ten sugar residues in AP, including T-Araf, 1,5-Araf, 1,2-Rhap, 1,3-Rhap, T-Galp, 1,3,5-Araf, 1,4-Galp, 1,4-GalpA, 1,6-Glcp, and 1,3,6-Glcp were identified using methylation and GC-MS. Combined with 1D and 2D NMR, it was further revealed that AP possesses a backbone of α-Galp-(1 → [3)-α-Rhap-(1 → 2)-α-Rhap-(1]2 → [4)-α-GalpA-(1]10 → 3,6)-β-Glcp-(1 → 6)-β-Glcp-(1 → 4)-β-Galp-(1 → 4)-β-Galp-(1→, with two branches: α-Araf-(1 → 5)-α-Araf-(1 → 5)-α-Araf-(1 → 3,5)-α-Araf-(1 → 6)-β-Glcp-(1→ and →3)-α-Rhap-(1 → 5)-α-Araf-(1 → 3,6)-β-Glcp-(1→ bonded to the C-3 of β-1,3,6-Glcp. AP significantly inhibited the release of cytokines and inflammatory mediators, such as TNF-α, IL-1β, IL-6, reactive oxygen species (ROS) and nitric oxide (NO). Western blotting results indicated that AP treatment markedly downregulated iNOS and NF-κB protein expression in LPS-induced RAW264.7 cells, leading to decreased levels of phosphorylated proteins (p-NF-κB and p-ΙκΒα) and preventing the degradation of ΙκΒα. Furthermore, in LPS-induced RAW264.7 macrophages, AP inhibited the expression of TLR4 protein, which in turn inhibited the activity of the NF-κB pathway. The findings demonstrated that AP exhibits anti-inflammatory properties in vitro by targeting the TLR4/NF-κB signaling pathway, thus impeding the nuclear translocation of NF-κBp65, suppressing the expression of related pro-inflammatory factors.

Preparation, characterization and in vitro antioxidant activities of a homogeneous polysaccharide from Prunella vulgaris

Prunella vulgaris is a medicinal and edible homologous plant, commonly used as a folk medicine to treat diseases. The Prunella vulgaris polysaccharides (PVPs) are reported with the antioxidant activity. This work was designed to isolate, characterize, and test the antioxidant activity of purified PVPs from P. vulgaris. A new homogeneous polysaccharide (PVP-1) was prepared by the DEAE column from PVPs, and diverse chromatography/spectroscopy and chemical methods were simultaneously employed to characterize the fine structure of PVP-1. The results showed PVP-1 had a triple helix structure, and the repeating structural unit of PVP-1 was composed of →6)-β-D-Galp-(1→6)-β-D-Galp-(3,1→6)-β-D-Galp-(1→6)-β-D-Galp-(1→ as the main chain, together with →6)-β-D-Galp-(1,3→1)-α-D-Araf-(5→1)-β-D-Galp-(4→1)-α-D-Galp-(2→ and →6)-β-D-Galp-(1,3→1)-α-D-GlcAp-(4→1)-α-D-Glcp-(4→1)-α-D-Galp as the branch chains. The main monosaccharides of PVP-1 were galactose (Gal, 41.25 %), galactose-OMe (Gal-OMe, 27.73 %), arabinose (Ara, 10.63 %), mannose (Man, 9.86 %), glucose (Glc, 3.88 %), glucuronic acid (GlcA, 2.86 %), ribose (Rib, 1.79 %), and xylose (Xyl, 1.76 %). In addition, the scanning electron microscopy (SEM) displayed that the surface of PVP-1 was rough and porous. PVP-1 gave the scavenging rates of the DPPH, ABTS, and hydroxyl radical lower than vitamin C at the same concentration, with the highest scavenging rate of DPPH radical at 82.71 % ± 4.19 % (5 mg/mL).

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

ETHNOPHARMACOLOGICAL RELEVANCE

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

AIM OF THE STUDY

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Structural characterization of oligosaccharide from Dendrobium officinale and its properties in vitro digestion and fecal fermentation

Oligosaccharides from Dendrobium officinale (DOO) is a kind of new potential prebiotic for health. In this study, structural characteristics, digestion properties and regulatory function on intestinal flora of DOO were investigated. An oligosaccharide, DOO 1-1, was purified by DEAE-Sepharose Fast Flow and Sephadex G-25, and its physicochemical properties were characterized as a glucomannan oligosaccharide with a molecular weight of 1560 Da (DP = 9). In vitro simulated digestion, it proved that the structure of DOO 1-1 was degraded hardly in the simulated gastric and small intestinal fluid. By evaluating the gas, short-chain fatty acids and intestinal microbiota in vitro fermentation, DOO has an excellent regulatory effect on intestinal microbiota, especially promoting the proliferation of Bacteroidetes and Actinobacteria. Therefore, DOO can be used as a potential prebiotic in functional foods.

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.

Optimization of Enzyme-Assisted Aqueous Extraction of Polysaccharide from Acanthopanax senticosus and Comparison of Physicochemical Properties and Bioactivities of Polysaccharides with Different Molecular Weights

To obtain the optimal process for the enzyme-assisted aqueous extraction of polysaccharides from Acanthopanax senticosus, and study the physicochemical properties of polysaccharides of different molecular weights, the extraction of Acanthopanax polysaccharides was optimized using the BBD response surface test. The polysaccharides with different molecular weights were obtained by ethanol-graded precipitation at 40%, 60%, and 80%, which were presented as ASPS40, ASPS60, and ASPS80. The polysaccharides were analyzed by HPGPC, ion chromatography, FT-IR, UV, SEM, TGA, XRD, Congo red, and I2-KI tests. The antioxidant assay was used to evaluate their antioxidant properties in vitro. The findings demonstrated that the recovery rate of Acanthopanax polysaccharide was 10.53 ± 0.682%, which is about 2.5 times greater compared to the conventional method of hot water extraction. Based on FT-IR, TGA, polysaccharides with different molecular weights did not differ in their structure or thermal stability. The XRD suggests that the internal structure of ASPSs is amorphous. Congo red and I2-KI showed that all three polysaccharides had triple helix structures with longer branched chains and more side chains. Furthermore, the antioxidant results showed the antioxidant activity of polysaccharides is not only related to the molecular weight size but also can be related to its composition and structure. These studies developed a green, and scalable method to produce polysaccharides from Acanthopanax senticosus and evaluated the properties of Acanthopanax polysaccharides of different molecular weights.

Interaction of barley β-glucan with food dye molecules - An insight from pulse dipolar EPR spectroscopy

The interactions between dietary fibers (DFs) and small molecules are of great interest to food chemistry and nutrition science. However, the corresponding interaction mechanisms and structural rearrangements of DFs at the molecular level are still opaque due to the usually weak binding and the lack of appropriate techniques to determine details of conformational distributions in such weakly organized systems. By combining our previously established methodology on stochastic spin-labelling of DFs with the appropriately revised set of pulse electron paramagnetic resonance techniques, we present here a toolkit to determine the interactions between DFs and small molecules, using barley β-glucan as an example for neutral DF and a selection of food dye molecules as examples for small molecules. The proposed here methodology allowed us to observe subtle conformational changes of β-glucan by detecting multiple details of the local environment of the spin labels. Substantial variations of binding propensities were detected for different food dyes.

Effects of Steaming on Sweet Potato Soluble Dietary Fiber: Content, Structure, and Lactobacillus Proliferation In Vitro

The influence of steaming treatment on the soluble dietary fiber (SDF) of sweet potato was investigated. The SDF content increased from 2.21 to 4.04 g/100 g (in dry basis) during 20 min of steaming. The microcosmic morphology of the fractured cell wall indicated the release of SDF components during steaming. The SDF from fresh (SDF-F) and 20 min steamed (SDF-S) sweet potato was characterized. The neutral carbohydrates and uronic acid levels in SDF-S were significantly higher than SDF-F (59.31% versus 46.83%, and 25.36% versus 9.60%, respectively) (p < 0.05). The molecular weight of SDF-S was smaller than SDF-F (5.32 kDa versus 28.79 kDa). The probiotic property was evaluated by four Lactobacillus spp. fermentation in vitro with these SDF as carbon source, using inulin as the references. SDF-F showed the best proliferation effects on the four Lactobacillus spp. in terms of the OD₆₀₀ and pH in cultures, and the highest production of propanoic acid and butyric acid after 24 h fermentation. SDF-S presented higher Lactobacillus proliferation effects, but slight lower propanoic acid and butyric acid production than inulin. It was concluded that 20 min of steaming released SDF with inferior probiotic properties, which might derive from the degraded pectin, cell wall components, and resistant dextrin.

Structural characterization of corn fiber hemicelluloses extracted by organic solvent and screening of degradation enzymes

An integrated treatment coupling peracetic acid delignification, dimethyl sulfoxide extraction, and ethanol precipitation were performed to isolate hemicellulose from de-starched corn fiber. Based on chemical composition, molecular weight distribution, methylation, and nuclear magnetic resonance spectroscopy, it is proposed that hemicelluloses in corn fiber were composed of two polysaccharides, glucuronoarabinoxylan (about 80 %) and xyloglucan (about 20 %). Xylose (about 46 %) and arabinose (about 32 %) were the main components in glucuronoarabinoxylan. More than half of the xylose units in the glucuronoarabinoxylan backbone chain were substituted at O-2 and/or O-3 by various monomers or oligomeric side chains. Based on structure analysis, five hemicellulases were selected and added to Penicillium oxalicum MCAX enzymes for enzymatic hydrolysis of corn fiber. The results showed that the addition of hemicellulases increased the sugar yield of corn fiber. These results demonstrate the effectiveness of enzyme consortium constructed by elucidating the chemical structure of hemicellulose in corn fiber for the degradation of corn fiber and also provide a general solution for the rational construction of targeted and efficient enzyme systems for the degradation of lignocellulosic biomass.

Polysaccharides from steam-processed Polygonatum cyrtonema Hua protect against d-galactose-induced oxidative damage in mice by activation of Nrf2/HO-1 signaling

BACKGROUND

Polygonatum cyrtonema Hua is cultivated for its edible and medical value. The steam-processed rhizome of P. cyrtonema is the main form for daily consumption and it has been used traditionally in tonics for treating various age-related disorders. The aim of our study was to compare the physicochemical properties and antioxidant activity of polysaccharides respectively extracted from crude P. Cyrtonema (PCPC), and steam-processed P. cyrtonema (PCPS), and to explore a possible underlying antioxidant mechanism.

RESULTS

The PCPC with a molecular weight of 4.35 × 10³  Da mainly consisted of fructose and trace amounts of glucose, whereas PCPS with 4.24 × 10⁴  Da was composed of fructose, arabinose, glucose, xylose, mannose, galacturonic acid and glucuronic acid. The PCPC had a triple-helical conformation whereas PCPS was a random coil. Both exhibited free radicals- scavenging activity in vitro. In a mouse model of oxidative damage, PCPC or PCPS treatment significantly reversed histopathological alterations, reactive oxygen species (ROS) accumulation and the reduction of antioxidant enzyme activity. They both also promoted Nrf2 nuclear transport by decreasing Keap-1 expression and increasing HO-1 expression. Both in vitro and in vivo, PCPS exhibited more potent antioxidant activity than PCPC.

CONCLUSION

Overall, the results suggest that PCPS has a stronger effect on the prevention of oxidative damage by activating Nrf2/HO-1 antioxidant signaling. This study demonstrates the role of steam-processed P. cyrtonema rhizome and provides valuable perspective for PCPS as a functional agent. © 2022 Society of Chemical Industry.

Biogenetic nanocarriers with enhanced pH stability formed by zein and selectively depolymerized mushroom hyperbranched β-glucans

Hyperbranched polysaccharide from Pleurotus tuber-regium (PTR-HBPS) is a β-glucan with high degree of branching (DB, 0.69) and a molecular weight (Mw) of 31.2 × 10⁵ g/mol with mixed β-1, 4/β-1, 4, 6/β-1, 6 glucosidic linkages. PTR-HBPS was depolymerized by cellulase and β-glucosidase under optimized conditions to form PC (PTR-HBPS depolymerized by cellulase) and PG (PTR-HBPS depolymerized by β-glucosidase) fractions with a minimum Mw of 2.74 × 10⁵ and 3.98 × 10⁵ g/mol, respectively. PC fractions had no significant changes for its primary structure in terms of glycosidic linkages, DB, and triple helical structure, while the DB of PG fractions was reduced to 0.63 with the loss of triple helical structure. Nanoparticles fabricated by PC fractions with zein showed better stability under different pH conditions. Enzymatic depolymerized low Mw β-glucan derived from PTR-HBPS with similar structural characteristics as the native one has potential as nanocarriers for food bioactive substances.

Pectic polysaccharides from Biluochun Tea: A comparative study in macromolecular characteristics, fine structures and radical scavenging activities in vitro

In this study, two acidic Biluochun Tea polysaccharides (BTP-A₁₁ and BTP-A₁₂) were investigated comparatively, which mainly consisted of Rha, Ara, Gal and GalA, possibly suggesting their pectic nature. Structurally, their galacturonan backbones composed of →4)-α-D-GalpA-(1→ and →2)-α-L-Rhap-(1→ were revealed similar, while Ara- and Gal-based branches attached to the O-2 of →2)-α-L-Rhap-(1→ were in distinctive types, proportions, extensibilities and branching degrees. This could lead to their different macromolecular characteristics, where BTP-A₁₁ with higher M_w presented a more hyper-branched chain conformation and relatively higher structural flexibility/compactness, thereby resulting in a lower exclusion effect and an insufficient hydrodynamic volume. Besides, better radical scavenging activities in vitro were also determined for Gal-enriched BTP-A₁₁, where a larger surface area containing more H-donating groups were related to its higher M_w, more hyper-branched conformation, lower DM and higher DA. Therefore, the understanding of structure-property-activity relationships was improved to some degrees for acidic Biluochun Tea polysaccharides, which could be potentially required for more applications in food, medical and cosmetic fields.

Characterization of Alpinia officinarum Hance polysaccharide and its immune modulatory activity in mice

This study aimed to verify the regulating effect of a novel water-soluble polysaccharide (AOHP) extracted from Alpinia officinarum Hance on mouse immunity and to characterize its structure feature. The cellulose...

Effects of ultrasound on the degradation kinetics, physicochemical properties and prebiotic activity of Flammulina velutipes polysaccharide

The controllable ultrasonic modification was hindered due to the uncertainty of the relationship between ultrasonic parameters and polysaccharide quality. In this study, the ultrasonic degradation process was established with kinetics. The physicochemical properties and prebiotic activity of ultrasonic degraded Flammulina velutipes polysaccharides (U-FVPs) were investigated. The results showed that the ultrasonic degradation kinetic models were fitted to 1/Mt-1/M0 = kt. When the ultrasonic intensity increased from 531 to 3185 W/cm2, the degradation proceeded faster. The decrease of polysaccharide concentration contributed to the degradation of FVP, and the fastest degradation rate was at 60 °C. Ultrasound changed the solution conformation of FVP, and partially destroyed the stability of the triple helix structure of FVP. Additionally, the viscosity and gel strength of FVP decreased, but its thermal stability was improved by ultrasound. Higher ultrasonic intensity led to larger variations in physicochemical properties. Compared with FVP, U-FVPs could be more easily utilized by gut microbiota. U-FVPs displayed better prebiotic activity by promoting the growth of Bifidobacterium and Brautella and inhibiting the growth of harmful bacteria. Ultrasound could be effectively applied to the degradation of FVP to improve its physicochemical properties and bioactivities.

Structural characteristics, anti-proliferative and immunomodulatory activities of a purified polysaccharide from Lactarius volemus Fr

Lactarius volemus Fr. is an edible mushroom widely consumed in China. Polysaccharide is an important nutritional component of L. volemus. This research aimed to isolate the polysaccharide from L. volemus and study its structure and bioactivities. A purified polysaccharide was identified and named as LVF-I whose primary structure was proposed considering the comprehensive results of monosaccharide composition, periodate oxidation-smith degradation, methylation analysis, FT-IR and 1D/2D NMR spectroscopy. Then the immunomodulation of LVF-I and its inhibition effect on H1299 and MCF-7 cells were investigated. Results showed that LVF-I (12,894 Da) contained fucose, mannose, glucose and galactose. It had a backbone consisting of →4)-α-D-Glcp-(1→, →6)-β-D-Manp-(1→, →6)-α-D-Galp-(1 → and →4)-β-D-Manp-(1→. And its side chains were branched at C2 of →4)-β-D-Manp-(1 → by →6)-α-D-Galp-(1→, α-D-Glcp-(1→, α-D-Galp-(1 → and α-L-Fucp-(1→. LVF-I (250-1000 μg/mL) could inhibit the proliferation of H1299 and MCF-7 cells, while enhance the proliferative response of splenocyte and the phagocytic ability of RAW264.7. Furthermore, LVF-I (250-1000 μg/mL) significantly induced the secretion of nitric oxide, interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) by up-regulating their mRNA expression in macrophages. These results suggested that LVF-I had the potential to be developed as antitumor or immunomodulatory agents by inhibiting the proliferation of tumor cells and stimulating macrophages-mediated immune responses.

Physicochemical, morpho-structural, and biological characterization of polysaccharides from three Polygonatum spp

Polygonatum species, including P. cyrtonema, P. kingianum, and P. sibiricum, are edible plants with medicinal purposes, which have long been consumed as food due to their high nutritional value. In this study, polysaccharides from P. cyrtonema (PCP), P. kingianum (PKP) and P. sibiricum (PSP) were obtained, and their physicochemical properties and in vitro biological activities were investigated. Our results demonstrated that PCP, PKP, and PSP consist of major fructose and minor glucose, galacturonic acid, and galactose in different molar ratios with the molecular weights of 8.5 × 10³ Da, 8.7 × 10³ Da, and 1.0 × 10⁴ Da, respectively. The three polysaccharides had triple-helical structures with β-d-Fruf, α-d-Glcp, α-d-Galp sugar residues, and an O-acetyl group, and displayed peak-shaped structures in different sizes. They also exhibited thermal, shear-thinning behavior and viscoelastic properties, and PCP presented the highest viscoelasticity. Moreover, they exerted strong free radical-scavenging abilities, and significant reducing capacity. PCP was the strongest, followed by PSP and then PKP. They significantly promoted the polarization of the M1 macrophage, with the effect of PCP ranking first. All three had similar effects on GLP-1 secretion. It is, therefore, necessary to identify the various roles of these three Polygonatum polysaccharides as functional agents based on their bioactivities and physicochemical properties.

Three Polygonatum polysaccharides with different physicochemical properties exert distinct effects on free radical-scavenging abilities and the promotion of M1 macrophage polarization, while they have similar effects on GLP-1 secretion.

Characterization of hydrophobic interaction of galactomannan in aqueous solutions using fluorescence-based technique

Fluorescence probing was used to study hydrophobic interactions of galactomannan (GM) obtained from fenugreek gum (FG), guar gum (GG), and locust bean gum (LBG) at different M/G ratios. The I₁/I₃ ratio of pyrene changed from 1.73 to 1.29, 1.22, and 1.29 for FG, GG and LBG, respectively, as the concentration of GM increased from 0.01 to 8.0 g/L at 30 °C. The critical aggregation concentration of FG, GG, and LBG increased from 1.04 to 3.84 g/L, 1.15 to 3.73 g/L, and 0.94 to 3.63 g/L, respectively, as temperature increased from 10 to 70 °C. Addition of Na₂SO₄ and NaSCN increased the I₁/I₃ ratio in dilute solution, but reduced it in semi-dilute solution, whereas adding urea reduced I₁/I₃ in dilute solution but increased it in semi-dilute solution. These results indicated that the CAC of GM, polarity and number of hydrophobic microdomains were highly dependent on the M/G ratio and galactose distribution.

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

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

Structures and anti-melanoma activities of two polysaccharides from Angelica sinensis (Oliv.) Diels

Polysaccharide is one of the necessary macromolecules in life activities, and it is also a very promising natural product for tumor prevention and treatment. In this study, two homogeneous polysaccharides (APS-4I and APS-4II) were isolated from Angelica sinensis (Oliv.) Diels. APS-4I was a linear glucan with molecular weight of 16.1 kDa, which was composed of 88.4% α-1,6-Glcp, 4.1% α-1,2-Glcp, 3.9% α-1,3-Glcp, and 2.8% α-T-Glcp. APS-4II was a novel polysaccharide with molecular weight of 11.1 kDa, which consisted of 55.4% α-1,6-Glcp, 10.4% α-1,3,5-Araf, 8.7% α-T-Araf, 9.2% α-1,5-Araf, 4.0% α-1,3-Araf, 3.6% α-1,4-Galp, and 9.1% β-1,3-Galp. NMR results demonstrated that APS-4II has a backbone composed of →6)-α-Glcp-(1 → 6)-α-Glcp-(1 → 5)-α-Araf-. (1 → 5)-α-Araf-(1 → 3,5)-α-Araf-(1 → 3)-β-Galp-(1 → 3)-β-Galp-(1 → 4)-α-Galp-(1 → 3)-α-Araf-(1 → 3,5)-α-Araf-(1→. Both APS-4I and APS-4II inhibited the tumor growth of B16-bearing mice, and the suppressive effect of APS-4II reached 64.7 ± 7.3%. Meanwhile, there were higher lymphocyte numbers and the levels of IL-2, IFN-γ, and TNF-α in peripheral blood of APS-4II-treated mice than those in APS-4I-treated mice. Furthermore, APS-4II showed a higher inhibitory effect on the proliferation of B16 cells and stronger promoting effects on the proliferation of splenocytes, the phagocytosis of peritoneal macrophages, and the cytotoxicity of NK cells. These results demonstrated that APS-4II could be a promising therapeutic agent for melanoma.

Interactive effects of molecular weight and degree of substitution on biological activities of arabinoxylan and its hydrolysates from triticale bran

Arabinoxylan (AX) has many beneficial health effects that are closely related to its structural characteristics. The current study aimed to investigate the effects of molecular weight (Mw) and degree of substitution (DS) on the antioxidant and hypoglycemic activities of triticale bran AX and its hydrolysates in vitro. At low and similar Mw, the antioxidant activity of AX was inversely proportional to its DS. When DS was close, the antioxidant activity of AX was inversely proportional to its Mw at high DS, but the opposite result was found at low DS. As for the hypoglycemic performance, when DS was similar, the hypoglycemic activity of AX was proportional to its Mw. At low and similar Mw, the α-glucosidase inhibitory ability and glucose adsorption ability of AX was positively correlated with DS, whereas the α-amylase inhibitory ability and glucose delayed absorption ability showed the opposite results. Mw and DS had significant effects on the antioxidant and hypoglycemic activities of AX, and these two factors often need to be combined to explain the varied effects under different conditions.

An ultrasonic-extracted arabinoglucan from Tamarindus indica L. pulp: A study on molecular and structural characterizations

In this study, an ultrasonic-extracted polysaccharide (nCPTP-55) was obtained with the highest yield (61.08%, w/w) from tamarind pulp, which consisted chiefly of total sugar (85.98%, w/w) with few protein (2.10%, w/w). Monosaccharide analysis showed nCPTP-55 was mainly composed of arabinose (39.19 mol%) and glucose (50.48 mol%) with negligible GlcA (2.05 mol%), indicating the neutral nature of nCPTP-55, which was further elucidated structurally via GC-MS and NMR, i.e., an arabinoglucan composed of →3)-β-D-Glcp-(1→ backbone with only T-α-L-Araf-(1→ branched at O-4 (27.82%) and O-6 (39.99%), resulting in relatively high A/G ratio (0.68-0.70). Based on MM2 minimized energy, the 3D schematic structures of nCPTP-55 could be considered as structural basis for its conformational behavior, which was preliminarily estimated via HPSEC-MALLS as between compact sphere and loosely hyper-branched chain (ρ = 0.84). Therefore, the relationship between molecular structure and conformational behavior was basically established for nCPTP-55, which was in a bid to have a better knowledge of its structure-property and structure-bioactivity relationships potentially required for more applications in food, cosmetic and pharmaceutical fields.

Plant-Derived Nutraceuticals and Immune System Modulation: An Evidence-Based Overview

Immunomodulators are agents able to affect the immune system, by boosting the immune defences to improve the body reaction against infectious or exogenous injuries, or suppressing the abnormal immune response occurring in immune disorders. Moreover, immunoadjuvants can support immune system acting on nonimmune targets, thus improving the immune response. The modulation of inflammatory pathways and microbiome can also contribute to control the immune function. Some plant-based nutraceuticals have been studied as possible immunomodulating agents due to their multiple and pleiotropic effects. Being usually more tolerable than pharmacological treatments, their adjuvant contribution is approached as a desirable nutraceutical strategy. In the present review, the up to date knowledge about the immunomodulating properties of polysaccharides, fatty acids and labdane diterpenes have been analyzed, in order to give scientific basic and clinical evidence to support their practical use. Since promising evidence in preclinical studies, limited and sometimes confusing results have been highlighted in clinical trials, likely due to low methodological quality and lacking standardization. More investigations of high quality and specificity are required to describe in depth the usefulness of these plant-derived nutraceuticals in the immune system modulation, for health promoting and disease preventing purposes.

Isolation, physical, structural characterization and in vitro prebiotic activity of a galactomannan extracted from endosperm splits of Chinese Sesbania cannabina seeds

The purpose of this study was to identify and determine the physical and structural characterization of the water-soluble galactomannan extracted from endosperm splits of Chinese S. cannabina seeds. The Sesbania galactomannan (SP) was extracted and purified using a novel method with a high yield (40.3 ± 7.2%). The molecular structure of SP was determined by monosaccharide composition, FTIR and NMR spectroscopy. The structural data showed that SP was galactomannan which composed by a β-(1/4)-linked mannose backbone with galactopyranosyl residues attached through α-(1/6) linkages. The constant mannose/galactose (M/G) ratio and average molecular weight (M_w) of SP was 1.6:1 and 2.16 × 10⁵ g/mol, respectively. The physical results revealed that SP had many branches on the backbone and existed as a random coil state in aqueous solution. SP was a good biopolymer which had smooth and clearer surface with homogeneous composition, and had some degree of crystallinity and prebiotic activity. As a consequence, SP could be a potential prebiotic and was expected to be suitable for applications in food, pharmaceutical, biomedical or cosmetic industries as a promising new biomaterial.

Physicochemical characterization of galactomannans extracted from seeds of Gleditsia sinensis Lam and fenugreek. Comparison with commercial guar gum

Gleditsia sinensis, fenugreek and guar galactomannans (referred to as GSG, FG, and GG) were extracted from their gums and investigated using various techniques. Mannose to galactose ratios were 3.55, 1.11, and 1.65, respectively. The intrinsic viscosity of GSG was very close to that of GG, while that of FG was the lowest one. This was attributed to the influence of high galactose substitution of FG on the mannan backbone, which induced a lower chain dimension due to intermolecular entanglement. High degrees of substitution and high temperatures contributed to improving the solubility of galactomannan. Rheological behavior indicated that GG had the highest apparent viscosity, yet the power-law model could well-fitted the flow curves of GSG and FG, but not GG. Through morphological observations, the extracted galactomannans exhibited rod-like structure in deionized water and showed fibrous filament network structure after dehydration by freeze-drying. The thermal behavior was greatly influenced by the degree of side groups and Mw of galactomannans.

Physicochemical properties of Arenga pinnata Merr. endosperm and its antidiabetic activity for nutraceutical application

This study aims to provide information on physicochemical properties of Arenga pinnata endosperm (APE) and its antidiabetic activity for utilization in the food and pharmaceutical industries. The antidiabetic effect of APE was studied through an observational experiment on the blood glucose level of rats. The physicochemical properties of APE were determined using a texturometer, X-ray powder diffraction, Brookfield viscometer, scanning electron microscopy, Fourier-transform infrared spectroscopy, and light microscope. The APE was categorized based on its texture into three groups. The crystal structure of APE is microspore and amorf while the hydrogel has a non-Newtonian property and is stable at 50°C. The viscosity index was increased in the increasing temperature with the order of high viscosity of APE being 1, 2, and 3. The hydrogel shape of APE 1 and 3 was lameral in the concentration of 1.25%. For antidiabetic study, the findings demonstrated that the APE could reduce the blood glucose level. The APE powders 1 and 2 with the respective weight of 50 and 200 mg have significant effects on reducing rat blood glucose level compared to the diabetic rats. Based on these properties, APE could potentially be used as a natural antidiabetic food without having any side effect and in the pharmaceutical industry for some purposes.

Pectic polysaccharides from purple passion fruit peel: A comprehensive study in macromolecular and conformational characterizations

A polysaccharide (PFPP) from purple passion fruit peel was optimally extracted, with the highest yield (10.05%, w/w) obtained under 35 °C extraction temperature, 240 W ultrasonic power, 65:1 mL/g liquid-to-solid ratio, 0.6% (w/v) ammonium oxalate, 30 min extraction time and pH 2.0. According to composition analyses, pectic PFPP and its fractions (PFPP-10, -15 and -20) were revealed as linear homogalacturonans interrupted by rhamnogalacturonan I in different lengths and extensities, where low esterification degrees (35.35-39.66%) were indicated via FT-IR. Furthermore, based on macromolecular models, comprehensive analyses on macromolecular and conformational characterizations of PFPP fractions were conducted quantitatively through, e.g., shape factor (1.42-1.79), Mark-Houwink-Sakurada exponent (0.55-0.74), conformational power-law exponent (0.52-0.58), fractal dimension (1.72-1.94) and persistence length (6.73-13.47 nm). Therefore, different semi-flexible coil conformations were proposed schematically, where lower molecular-weight PFPP fractions were less flexible. This could provide a molecular basis for precise re-utilizations of PFPP in food and pharmaceutical industries.

Molecular properties and structural characterization of an alkaline extractable arabinoxylan from hull-less barley bran

An alkaline extractable arabinoxylan (HBAX-25) was fractionated from crude arabinoxylan (HBAX) obtained optimally in hull-less barley (Hordeum vulgare L. var. nudum Hook. f.) bran. Molecular properties and structural characterization of HBAX-25 were investigated thoroughly based on chemical composition of 8.31% (w/w) moisture and 87.57% (w/w) sugar with specifically few proteins (1.08%, w/w) and high arabinoxylans (82.46%, w/w). Data from monosaccharide composition indicated that HBAX-25 mainly consisted of arabinose (30.13 mol%) and xylose (51.55 mol%) with A/X ratio of 0.58, representative for arabinoxylans, which coincided with FT-IR results and was corroborated by methylation and NMR analyses, i.e., a relatively low-branched arabinoxylan composed of un-substituted (1,4-linked β-D-Xylp, 71.19%), mono-substituted (1,3,4-linked β-D-Xylp, 14.78%) and di-substituted (1,2,3,4-linked β-D-Xylp, 10.76%) xylose units as backbone via β-(1→4) linkages, with six possible branches or individuals included. Hence, a structural basis of HBAX-25 was established, which could have potential in food and other value-added applications capable of interpreting their physicochemical, functional and technological characteristics.

Structure characterization, physicochemical property and immunomodulatory activity on RAW264.7 cells of a novel triple-helix polysaccharide from Craterellus cornucopioides

In the study, a new triple-helix polysaccharide with favorable stability was purified from C. cornucopioides. Its structural characterization, stability and solution behavior were investigated by the GC-MS, periodate oxidation-smith degradation, FT-IR, 1D and 2D NMR spectroscopy, methylation analysis, Scanning electron microscope, Congo-red, CD, TGA and DSC analysis. The results showed that Craterellus cornucopioide polysaccharide (CCP) possessed the molecular weight of 1.97 × 10³ kDa, is mainly composed of mannose (48.73%), galactose (17.37%), glucose (15.97%) and xylose (17.93%), respectively. It was a heteroglycan with (1 → 3)‑linked‑β‑d‑Manp‑(1 → 6)‑linked α‑d‑Galp backbone distributed by (1 → 4)‑linked‑α‑d‑Xylp‑t‑α‑d‑Manp and t‑β‑d‑Glup units at O-6. The result of TGA and DSC assay indicated that CCP has a favorable thermal stability. MTT and Scanning electro microscopy (SEM) assay showed that CCP could significantly improve the proliferation activity and induce cells activation of RAW264.7 in a certain range of concentrations and period.

Mannans: An overview of properties and application in food products

This review aims to emphasize the occurrence and abundant presence of mannans in nature, their classification, structural differences and significance in food and feed industry. With rising demand from the consumers' end for novel natural foods, usage of galactomannan and glucomannan has also increased alternatively. Non toxicity of mannans permits their usage in the pharmaceutical, biomedical, cosmetics, and textile industries. In the food industry, mannans have various applications such as edible films/coating, gel formation, stiffeners, viscosity modifiers, stabilizers, texture improvers, water absorbants, as prebiotics in dairy products and bakery, seasonings, diet foods, coffee whiteners etc. Applications and functions of these commonly used commercially available mannans have therefore, been highlighted. Mannans improve the texture and appeal of food products and provide numerous health benefits like controlling obesity and body weight control, prebiotic benefits, constipation alleviaton, prevent occurrence of diarrhea, check inflammation due to gut related diseases, management of diverticular disease management, balance intestinal microbiota, immune system modulator, reduced risk of colorectal cancer etc. Mannan degrading enzymes are the key enzymes involved in degradation and are useful in various industrial processes such as fruit juice clarification, viscosity reduction of coffee extracts etc. besides facilitating the process steps and improving process quality.