Structural characterization, α-amylase and α-glucosidase inhibitory activities of polysaccharides from wheat bran

Gut microbiota-based bioassay for the quality evaluation of different species of Dendrobium and their therapeutic potential in type 2 diabetes

BACKGROUND

Dendrobium (DEN) have been utilized as valuable medicinal resource in China used for millennia for prevention and treatment of various diseases, particularly diabetes via alteration of their disordered gut microbiota.

PURPOSE

The current study aimed to differentiate the quality of different species of DEN via an in vitro system including gut microbiota fermentation followed by antioxidative and hypoglycemic bioassays.

MATERIAL AND METHODS

About 100 g fresh DEN from four species (DEN-5 ~ DEN-8) was extracted with 1L boiling water twice with 1 h each time followed by centrifugation to obtain the supernatants as DEN aqueous extract. About 10 mg/mL of each DEN aqueous extract was fermented with fecal fluid from db/db mice for 12, 24 and 48 h, followed by monitoring the changes in total polysaccharide and polyphenol contents, antioxidative, hypoglycemic activities. Additionally, the level of short chain fatty acids and the abundance/diversity of gut microbiota in the DEN fermentation mixture were monitored via GC/MS and 16S rRNA, respectively. Moreover, in vivo hypoglycemic activities of DEN-5 ~ DEN-8 at the dosage of 200 mg/kg once daily for 14 days were also evaluated in db/db mice.

RESULTS

DEN-5 ~ 8 varied in the content of polysaccharides (0.23-0.61, w/w) and polyphenol (0.008-0.023, w/w). Based on the free radical scavenging percentage, DEN antioxidative activities ranked as DEN-7≈DEN-8 > DEN-5 ≈DEN-6. Based on the percentage of enzyme inhibition, DEN antihyperglycemic activities ranked as DEN-5≈DEN-6 > DEN-8 > DEN-7. Hypoglycemic activities of DEN-5 ~ 8 in db/db mice were in the order of DEN-5≈DEN-6 > DEN-8 > DEN-7. Further correlation analyses of DEN polysaccharides content, DEN polyphenol content, SCFAs formation after in vitro fermentation, antioxidant activities, and hypoglycemic activities found that 1) polysaccharides contents in DEN-5 ~ 8 were positively correlate with total SCFAs generated after the fermentation, α-glucosidase inhibitory capacity, α-amylase inhibitory capacity, and GLP-1 level; 2) polyphenol contents in DEN-5 ~ 8 were positively correlate with ABTS, DPPH, and superoxide anion scavenging capacity.

CONCLUSIONS

Our current study for the first time utilized a novel in vitro system to assess the hypoglycemic effects of different species of DEN and indicated that polysaccharides content in DEN was positively correlated with hypoglycemic effect while polyphenol content in DEN was positively correlated with antioxidant activity.

Anti-inflammation and intestinal flora modulation ability of Moutan Cortex polysaccharide and its interaction with soybean protein isolate

The development of plant polysaccharides for anti-inflammation and gut flora modulation has attracted extensive attention; however, it remains to be investigated whether the interaction between active polysaccharides and other macromolecules in the food matrix influences polysaccharide activity. In this study, a homogeneous heteropolysaccharide was purified from Moutan Cortex polysaccharide (PMCW1), the main glycosidic bonds of which were comprised of T-α-Araf-(1→, →5)-α-Araf-(1→, →3,5)-α-Araf-(1→, →3,4)-α-Glcp-(1→, and →4)-β-Galp-(1 → residues. PMCW1 reduced the Firmicutes/Bacteroidetesh ratio, promoted the growth of Prevotella, Bifidobacterium, and Lactobacillus, and increased SCFAs levels. Additionally, PMCW1 down-regulated the NO production and pro-inflammatory factor levels in lipopolysaccharide-induced RAW 264.7 macrophages. In the simulated plant protein beverage system, the PMCW1-soybean protein isolate complex formed in non-covalent interactions with better stability and solubility, which maintained their anti-inflammation effects after gastrointestinal digestion. These results provide a new perspective for the development of PMCW1 as a promising functional food ingredient for preventing and mitigating metabolic diseases.

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.

Exploring the effects of milk-enriched walnut soy sauce: Insights from GC-IMS and metagenomics approach to flavor and microbial shifts

This study investigates the impact of milk addition on the fermentation of walnut soy sauce, using Gas Chromatography-Ion Mobility Spectrometry (GC-IMS) and metagenomics to analyze flavor profiles and microbial dynamics. GC-IMS analysis showed significant increases in volatile compounds such as esters (ethyl acetate), aldehydes (hexanal), and alcohols (isoamyl alcohol), enhancing the aroma and taste. Metagenomic analysis revealed that milk increased microbial diversity, with Weissella and Lactobacillus dominating early fermentation. The milk-enriched soy sauce (SYM) exhibited higher amino acid nitrogen (2.67 g/L), and total nitrogen (7.18 g/L) compared to the control, indicating improved nutritional quality. Protease activity peaked at 2438.5 U/g for neutral protease, supporting efficient protein hydrolysis. Relative Odor Activity Value (ROAV) analysis identified 29 key flavor compounds, including 3-methyl butanol and ethyl 2-methyl butyrate, which contributed fruity and buttery notes to SYM. These results suggest that milk enhances microbial growth and improves both flavor and nutritional quality of walnut soy sauce.

Prospects of Corn (Zea mays L.) Polysaccharides: Structural Features, Bioactivities, and Applications

Over the past few years, the identification and study of bioactive and health-promoting new ingredients from natural sources have garnered significant interest. Corn has increasingly come into focus due to its substantial nutritional and medicinal benefits. Research studies have shown that corn polysaccharide exhibits antitumor, antioxidative, hepatoprotective, renoprotective, hypoglycemic, immunomodulatory, and various other beneficial effects. Furthermore, variations in extraction materials and methods can result in differences in the structural and biological properties of corn polysaccharides. This article reviews the latest advancements in the extraction and purification techniques, structural characteristics, biological activities, structural modifications, and toxicological assessments of corn polysaccharides. The aim is to furnish evidence that supports the further development of corn polysaccharides as therapeutic agents and functional food ingredients.

Structural characterization and hypoglycemic activity of a polysaccharide from Imperatae Rhizoma

In this study, high-temperature high-pressure ultrasound-assisted extraction method was used to extract polysaccharides from Imperatae Rhizoma (IRP). The yield of IRP was 14.79 ± 0.12 % under the optimal extraction conditions. IRP was purified by a DEAE-52 cellulose column and a Sephadex G-100 chromatography column to obtain two homogeneous fractions: IRP-0 and IRP-1. IRP-1 showed better inhibitory activity than IRP-0 in α-glucosidase inhibition assay. The chemical structure of IRP-1 was further characterized using molecular weight distribution, monosaccharide composition, infrared spectroscopy, methylation analysis, and nuclear magnetic resonance. The results indicated that IRP-1 (29.79 kDa) was a heteropolysaccharide composed of rhamnose, arabinose, galactose, glucose, xylose, mannose, and glucuronic acid, with a molar ratio of 2.48:11.76:20.08:50.92:10.25:2.08:2.12. The backbone of IRP-1 consisted of →6)-β-D-Glcp-(1→, →3,6)-α-D-Galp-(1→, →4)-β-L-Xylp-(1→, and →5)-Araf-(1→. The results of the in vitro hypoglycemic experiments showed that IRP-1 effectively improved glucose consumption and glycogen synthesis, pyruvate kinase (PK), and hexokinase (HK) activities in insulin-resistant HepG2 (IR-HepG2) cells. Additionally, IRP-1 significantly increased the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), and the levels of glutathione (GSH), while reducing the levels of malondialdehyde (MDA) and reactive oxygen species (ROS), demonstrating its significant hypoglycemic activity. The findings provide a scientific foundation for the development and utilization of polysaccharides from Imperatae Rhizoma, suggesting their potential application in the treatment of diabetes.

A Comparative Study on Physicochemical Properties and Biological Activities of Polysaccharides from Coreopsis tinctoria Buds Obtained by Different Methods

In this study, the polysaccharides of Coreopsis tinctoria buds (CTBPs) were extracted by hot water, ultrasound, alkali solution, and acid solution, and the four kinds of extracted polysaccharides were denoted Hw, Ultra, Al, and Ac. Then, the Hw were degraded by ultrasound, an alkali solution, and an acid solution, and the three resultant kinds of polysaccharides were denoted Ultra-Post-proc, Al-Post-proc, and Ac-Post-proc. The study comprehensively compared and analyzed the physical and chemical characteristics, structural properties, and in vitro activities of each polysaccharide. The extraction and treatment methods significantly affected the chemical composition, molecular weight (Mw) and potential of the CTBPs. The contents of carbohydrates, total phenol, and protein in Al were the highest, at 78.79 ± 0.62%, 81.69 ± 0.70 mg GAE/g and 4.82 ± 0.10%, respectively. The different methods did not change the monosaccharide composition of CTBPs, but affected the monosaccharide proportion and reduced the Mw of CTBPs. The absolute zeta potential value of Al was the highest, indicating that the solution was the most stable. CTBPs had the characteristic structure of polysaccharides, and Al-Post-proc had a triple helix structure. Additionally, CTBPs also had good water and oil holding abilities, as well as bile acid binding ability. CTBPs displayed good activity in vitro, among which Al possessed the best α-glucosidase inhibitory activity and the strongest free radical scavenging ability, and also well inhibited the generation of glycosylation products and protein oxidation products in the bovine serum albumin (BSA)-fructose model. These findings provide support for a theoretical basis for the application of polysaccharide from Coreopsis tinctoria bud in pharmaceutical and functional foods.

Effects of Fortified Wheat Bran Arabinoxylan on the Quality of Wheat Malt Beer

Arabinoxylan, a key non-starch polysaccharide in wheat bran, significantly influences the quality and health benefits of wheat beer. This study aimed to investigate how wheat bran addition (0-20%) affects water-extracted arabinoxylan (WEAX) content and beer quality in 100% wheat malt beer. The study integrated physicochemical analyses (polysaccharide composition, WEAX molecular weight), process parameters (wort filtration time, foam stability), and sensory evaluation to establish structure-function relationships. Results showed that the WEAX content in beer increased from 1.36 mg/mL in pure malt beer (0% bran) to 2.25 mg/mL with 20% bran addition. Bran addition shortened wort filtration time by 20-45%. The molecular weight of WEAX was mainly 2936-7062 Da, enhancing foam expansion (36.18%) and stability (15.54%) due to elevated polymerization and arabinose-to-xylose (A/X) ratios. WEAX fractions (7062-10,134 Da and 859-2936 Da) correlated positively with beer turbidity and viscosity. Sensory analysis identified 15% bran as optimal for balanced quality. These findings demonstrate that bran addition enhances WEAX content, polymerization, and A/X ratios, improving foam performance, reducing filtration time, and optimizing beer quality without altering arabinogalactan, glucan, or mannose polymer content.

Preparation and structural characteristics of polysaccharides from loquat peel waste, and their preliminary bioactivities

BACKGROUND

Loquat peel, often as food waste, is a valuable source of bioactive polysaccharides. However, study of such polysaccharides is insufficient, leaving a significant gap in understanding their preparation, structure and bioactivities.

RESULTS

In this study, three types of loquat peel polysaccharides (LPWP, LPHP and LPNP) were sequentially extracted using hot water, HCl and NaOH solutions, respectively. Among them, LPWP was the purest, with a yield of 3.4% and molecular weight of 470.6 kDa, and it differed from LPHP and LPNP in structure, as evidenced by Fourier transform infrared spectroscopy, X-ray diffraction and scanning electron microscopy, which demonstrated that LPWP consisted of more arabinose (Ara) but less galacturonic acid, rhamnose and galactose, with molar percentages of 71.3%, 23.3%, 3.5% and 1.9%, respectively. Besides, LPWP also exhibited superior antioxidant and antihyperglycemic activities in vitro, particularly in inhibiting α-amylase and α-glucosidase. Methylation and nuclear magnetic resonance analysis confirmed that LPWP was a methyl-esterified pectic polysaccharide rich in branched arabinan, as evidenced by the notable proportion of α-Ara residues, including T-α-Araf, 1,5-α-Araf and 1,2,3,5-α-Araf, with molar percentages of 27.1%, 23.1% and 10.2%, respectively. AFM imaging further revealed its branched-chain morphology and aggregation behavior.

CONCLUSION

This study highlights the potential of loquat peel polysaccharides as a bioactive ingredient with significant antioxidant and antihyperglycemic properties, particularly LPWP, which was found as a methyl-esterified pectic polysaccharide with abundant-branched arabinan. Our work provides valuable insights into the application of loquat peel polysaccharides in functional foods. © 2024 Society of Chemical Industry.

Tailored NADES solvents for the extraction optimization of benzylisoquinoline alkaloids from Thalictrum foliolosum DC.- A potential phyto-nutraceutical source

From a perspective focused on phyto-nutraceuticals, alkaloids are considered to be the most significant metabolites, as they exhibit a broad range of pharmacological applications. Therefore, it is essential, to conduct a thorough investigation of the extraction techniques employed and to optimize the overall process. Considering this, we delved into tailor-made natural deep eutectic solvents coupled with ultrasonic-assisted extraction and macroporous resins aided recovery of therapeutics alkaloids from Thalictrum foliolosum DC. The extraction parameters including duty cycle (X1), extraction time (X2), water content (X3), and liquid-to-solid ratio (X4) were optimized through response surface methodology. Under the optimal extraction conditions [duty cycle- 61 %, ultrasonication extraction time- 10.35 min, water content- 30.51 %, and liquid-to-solid ratio- 30 mL/g], the yield of berberine (11.91 ± 0.12 mg/g DW), berbamine (11.85 ± 0.16 mg/g DW), magnoflorine (6.06 ± 0.05 mg/g DW), and palmatine (2.53 ± 0.015 mg/g DW) were found to be near the model prediction. Further, adsorption/desorption characteristics were investigated, and the results highlight AB-8 resin as most effective for the recovery of berberine and palmatine, while, XAD-7HP resin is best suited for berbamine and magnoflorine. FT-IR analysis shows similar spectra among the purified extracts with significantly (p < 0.05) higher antioxidant and anti-glycemic activities. In conclusion, the developed method complies with the criteria of green extraction which can be harnessed as a natural antioxidant in pharmaceutical and nutraceutical industries.

Immunomodulatory activity of red algal galactans and their partially depolymerized derivatives in RAW264.7 macrophages

Funoran and furcellaran were isolated through a successive cascade extraction process, followed by the depolymerization of extracted polymers via an auto-hydrolysis process. The molecular weight and structural peculiarities of both native and partially depolymerized polysaccharides were investigated using size-exclusion chromatography (SEC), FTIR, and NMR spectroscopy. Immunotropic effects of the native and partially depolymerized polysaccharides were explored through various in vitro assays. Although both higher and lower molecular weight funoran exhibited anti-inflammatory activity on LPS-stimulated RAW264.7 cells by significantly downregulating iNOS and COX-2 gene expression, as well as the secretion of pro-inflammatory cytokines, native funoran performed slightly better. Conversely, higher molecular weight furcellaran remarkably activated RAW264.7 cells compared to the non-treated control by inducing inflammatory mediators and pro-inflammatory cytokines, including the anti-inflammatory cytokine IL-10. Lower molecular weight furcellaran was unable to activate the macrophages, showing a similar behavior pattern to funoran samples in LPS-treated cells. Furthermore, the TLR4/NF-κB signaling pathway appears to be modulated by sulfated polysaccharides, leading to both anti-inflammatory and immunostimulatory responses in RAW264.7 cells through blocking and activating mechanisms. These findings indicate that sulfated polysaccharides could be promising therapeutic agents, and indeed, the molecular weight of polysaccharides plays a crucial role in the immune response of RAW264.7 macrophages.

Improvement of lactose digestion by highland barley (Hordeum vulgare var. coeleste L.) β-glucan: Activation of lactase under simulated gastric/small intestinal digestive conditions

β-Galactosidase (lactase) plays a crucial role as a dietary supplement in managing lactose intolerance. Here, the catalytic activity of lactase was successfully activated for the first time through complexation with water-extractable β-glucans from highland barley (WHBG). Under simulated gastric/small intestinal digestive conditions, WHBG and lactase spontaneously formed complexes, resulting in a remarkable increase in catalytic activity up to 172.6 %. Structural analyses revealed that the incorporation of WHBG caused partial unfolding of lactase, thereby exposing its hydrophobic regions with active sites, and the electrostatic and hydrophobic interactions between the two played pivotal roles. Meanwhile, according to microstructure and particle size analyses, the dissociation of aggregates and the re-distribution of lactase molecules were also observed. Consequently, the enzyme-substrate contact was promoted, and the hydrolysis efficiency of complexed lactase in the digestion of lactose in milk was superior to that of native lactase. Notably, among WHBG30/50/70 obtained by continuous fractionation of WHBG with 30 %/50 %/70 % ethanol, WHBG70 exhibited the lowest molecular weights and size, and the highest negative ζ-potential, potentially contributing to its superior activation abilities on lactase. These findings challenge the traditional view of polysaccharides as enzyme inhibitors and highlight their potential for diverse applications.

Ultrasonic-Assisted Extraction, Structural Characteristics, and Activity of Polysaccharides From Gymnocladus chinensis Baill

In this study, the response surface method (RSM) was used to determine the optimal parameters of ultrasonic-assisted extraction of Gymnocladus chinensis Baill. polysaccharides (GCBPs). The optimal extraction conditions were as follows: a liquid-solid ratio of 50.4 mL/g, an extraction temperature of 60°C, an extraction time of 43 min, and an extraction power of 240 W. Under these conditions, the extraction rate of GCBP reached 50.1%. Three fractions of GCBP-40, GCBP-60, and GCBP-80 with sugar contents of 64.33%, 59.16%, and 59.46% were obtained by different concentrations of ethanol purification. All the three fractions consisted of six monosaccharides with different ratios, namely, Man, Rha, Gal, Glu, Ara, and Xyl. From Congo red test, it is confirmed that all three fractions could have a triple helix structure. In addition, the antioxidant and hypoglycemic experiments showed that all three components had excellent antioxidant activity (2,2-diphenyl-1-picrylhydrazyl [DPPH] free-radical scavenging activity, 2,2-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) [ABTS] free-radical scavenging activity, and OH- free-radical scavenging activity) and hypoglycemic activity (α-glucosidase inhibitory activity).

In vivo anti-diabetic and anti-lipidemic evaluations of an excellent synthetic α-glucosidase inhibitor with dihydropyrano[3,2-c]quinoline skeleton

Objectives

The in vivo assay is a key step in the development of a new bioactive compound as a lead drug structure. Based on importance of α-glucosidase inhibitors in the control of blood glucose level (BGL) in diabetes, in the present work, 3-amino-1-(4-chlorophenyl)-12-oxo-11,12-dihydro-1H-benzo[h]pyrano[3,2-c]quinoline-2-carbonitrile (ACODDHBPQC) that showed excellent inhibitory activity on the yeast form of α-glucosidase was selected for in vivo anti-diabetic assay.

Methods

The in vivo anti-diabetic and anti-lipidemic effects of this synthetic compound were evaluated using by a streptozotocin (STZ)-induced diabetic Wistar rat model. In silico docking study of ACODDHBPQC was performed by Atodock tools and absorption, distribution, metabolism, excretion, and toxicity (ADMET) properties of this compound was predicted by PreADMT online software.

Results

The obtained results revealed that selected compound ACODDHBPQC showed a significant anti-diabetic effect on diabetic rats. In vivo anti-lipidemic assay also demonstrated that ACODDHBPQC had favorable effects on cholesterol and LDL levels. Furthermore, in silico studies showed that ACODDHBPQC interacted with key residues of the α-glucosidase active site and had good pharmacokinetic and toxicity properties.

Conclusion

In summary, anti-hyperglycemic effects of ACODDHBPQC was confirmed by in vivo study. However, more evaluations are needed to introduce ACODDHBPQC as a lead drug compound.

Graphical abstract

Comparison of polysaccharides from stem barks and flowers of Magnolia officinalis: Compositional characterization, hypoglycemic and photoprotection activities

The extraction of polysaccharides from stem barks and flowers of Magnolia officinalis were optimized using response surface methodology and the maximum yields were 4.12 ± 0.06 % and 5.5 ± 0.08 %, respectively. Three homogeneous polysaccharides including MOBP-I, MOBP-II and MOFP-I were further purified and their compositional characterization were compared. Molecular weights of MOBP-I, MOBP-II and MOFP-I were 5.9 × 103, 6.8 × 103 and 3.9 × 104 Da, respectively. Gas chromatography (GC) analysis suggested that MOBP-I, MOBP-II and MOFP-I were composed of rhamnose, arabinose, mannose, glucose and galactose at different ratios and exhibited different appearance and glycosidic linkages. MOFP-I but not MOBP-I and MOBP-II had three helix structures. MOBP-I, MOBP-II and MOFP-I showed significant hypoglycemic and photoprotection capacities with different efficacy. MOBP-I had greater hypoglycemic activity, as evidenced by the increased α-glucosidase inhibition activity and glucose consumption in insulin-resistant HepG2 cells. MOBP-II and MOFP-I were more powerful in reversing ultraviolet-B (UVB)-irradiated photoaging of HaCaT cells. The difference of polysaccharides compositions might explain for their bioactivity discrepancy.

Purification, structural identification, in vitro hypoglycemic activity and digestion characteristics of polysaccharides from the flesh and peel of wampee (Clausena lansium)

In this study, two polysaccharides were isolated from the flesh and peel of wampee, termed as PWP-F and PWP-P respectively, and their structural characteristics, in vitro antioxidant and hypoglycemic activities and digestion were investigated. Results indicated the molecular weight of PWP-F was higher than that of PWP-P and they were both mainly composed of galactose and arabinose. Both polysaccharides exhibited α-type and β-type glycosidic linkages based on FTIR analysis. NMR spectroscopy revealed that PWP-F mainly consisted of α-Araf-(1→, →3,5)-α-Araf-(1→, →2,5)-α-Araf-(1→, →4) → β-Galp-(1 → and α-GalpA-(1→, while PWP-P was composed of α-Araf-(1→, →3)-α-Araf-(1→, →5)-α-Araf-(1→, →3,6) → β-Galp-(1→ and α-GalpA-(1→. Scanning electron microscopy showed that PWP-P had more porous surface structure compared to PWP-F. Moreover, PWP-P exhibited superior antioxidant activity and significant inhibition of both α-glucosidase and α-amylase compared to PWP-F. Specifically, PWP-P demonstrated mixed inhibition against α-glucosidase and α-amylase. In vitro digestion results showed the molecular weight, polysaccharide and reducing sugar content of PWP-F and PWP-P decreased after simulative gastrointestinal digestion. Overall, PWP-P has great potential as a kind of new antioxidant and hypoglycemic agent.

Star anise (Illicium verum Hook. F.) polysaccharides: Potential therapeutic management for obesity, hypertension, and diabetes

This study explores the extraction of polysaccharides from star anise (Illicium verum Hook. f.) with its anti-obesity, antihypertensive, antidiabetic, and antioxidant properties. The aim is to optimize the extraction conditions of star anise polysaccharides (SAP) utilizing propane alcohols-based deep eutectic solvents and microwave-assisted methods. The optimized conditions resulted in an extraction yield of 5.14%. The characteristics of acidic pectin-like SAP, including high viscosity (44.86 mPa s), high oil-holding capacity (14.39%), a high degree of esterification (72.53%), gel-like properties, highly amorphous, a high galacturonic acid concentration, and a highly branching size polysaccharide structure, significantly contribute to their potent inhibition of pancreatic lipase (86.67%), angiotensin-converting enzyme (73.47%), and α-glucosidase (82.33%) activities as well as to their antioxidant properties of azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS, 34.94%) and ferric ion reducing antioxidant power (FRAP, 0.56 mM FeSO4). Therefore, SAP could be used as a potential therapeutic agent for obesity, hypertension, and diabetes mellitus management.

Preparation, Structural Characterization, and Hypoglycemic Activity of Dietary Fiber from Sea Buckthorn Pomace

Sea buckthorn pomace is often discarded as a by-product during the sea buckthorn processing stage. Consequently, its richness in dietary fiber is usually overlooked. In this study, soluble dietary fiber (SDF) and insoluble dietary fiber (IDF) were extracted from sea buckthorn pomace using ultrasound combined with the enzyme method. The optimal values of the independent variable were determined by a combinatorial design and a response surface optimization test with SDF/IDF as the dependent variable, prepared as follows: 5% enzyme addition, ultrasonic power of 380 W, enzymatic time of 30 min, and alcoholic precipitation liquid ratio of 4:1. Under these conditions, the SDF/IDF ratio was 17.07%. The structural characterization and hypoglycemic activity of the two dietary fibers were then compared. The results show that two dietary fibers have respective structures and functional groups of fibers. SDF was less crystalline than IDF, and its structure was looser. Furthermore, the hypoglycemic activity of SDF was significantly better than IDF's (p < 0.05). The glucose adsorption capacity of SDF was 1.08-1.12 times higher than that of IDF. SDF inhibited α-amylase and α-glucosidase by 1.76 and 4.71 times more than IDF, respectively. These findings provide a reference for improving the utilization of sea buckthorn processing by-products.

Extraction, purification, chemical characterization, and in vitro hypoglycemic activity of polysaccharides derived from Rosa laevigata Michx

This study aimed to optimize the extraction process of polysaccharides from Rosa laevigata Michx. (RLMP) using an ultrasound-microwave-assisted method and investigate its in vitro hypoglycemic activity. Key factors affecting RLMP yield were identified using a Plackett-Burman design, followed by a Box-Behnken design and response-surface methodology, to determine the optimal extraction conditions. RLMP was purified using DEAE-52 cellulose, yielding two homogeneous fractions: RLMP-1 and RLMP-2. Monosaccharide composition was analyzed by gas chromatography, and structural characterization of RLMP, RLMP-1, and RLMP-2 was performed using FT-IR, SEM, and TEM. Methylation analysis and NMR were used to elucidate the sugar-chain structure of RLMP-1. In vitro hypoglycemic activity analysis showed that RLMP improved the glucose consumption and glycogen synthesis and enhanced the activities of pyruvate kinase and hexokinase in IR-HepG2 cells. Moreover, RLMP significantly increased the activities of antioxidant enzymes, such as CAT, SOD, and GSH-Px and decreased those of ROS and MDA. Western blotting analysis confirmed that RLMP enhances glucose and lipid metabolism and reduces oxidative stress by activating the PI3K/Akt/GLUT-4 signaling pathway, thereby exerting its hypoglycemic effect. These findings suggest that RLMP is a promising candidate for developing novel antioxidant agents or hypoglycemic drugs.

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.

Unlocking the Potential of Food Waste: A Review of Multifunctional Pectins

This review comprehensively explores the multifunctional applications of pectins derived from food waste and by-products, emphasizing their role as versatile biomaterials in the medical-related sectors. Pectins, known for their polyelectrolytic nature and ability to form hydrogels, influence the chemical composition, sensory properties, and overall acceptability of food and pharmaceutical products. The study presents an in-depth analysis of molecular parameters and structural features of pectins, such as the degree of esterification (DE), monosaccharide composition, galacturonic acid (GalA) content, and relative amounts of homogalacturonan (HG) and rhamnogalacturonan I (RG-I), which are critical for their technofunctional properties and biological activity. Emphasis is placed on pectins obtained from various waste sources, including fruits, vegetables, herbs, and nuts. The review also highlights the importance of structure-function relationships, especially with respect to the interfacial properties and rheological behavior of pectin solutions and gels. Biological applications, including antioxidant, immunomodulatory, anticancer, and antimicrobial activities, are also discussed, positioning pectins as promising biomaterials for various functional and therapeutic applications. Recalled pectins can also support the growth of probiotic bacteria, thus increasing the health benefits of the final product. This detailed review highlights the potential of using pectins from food waste to develop advanced and sustainable biopolymer-based products.

Fermentation of millet bran with Bacillus natto: enhancement of bioactivity levels and the bioactivity of bran extract

BACKGROUND

Millet bran (MB), a byproduct of millet production, is rich in functional components but it is underutilized. In recent years, researchers have shown that fermentation can improve the biological activity of cereals and their byproducts. This study used Bacillus natto to ferment millet bran to improve its added value and broaden the application of MB. The bioactive component content, physicochemical properties, and functional activity of millet bran extract (MBE) from fermented millet bran were determined.

RESULTS

After fermentation, the soluble dietary fiber (SDF) content increased by 92.0%, the β-glucan content by 164.4%, the polypeptide content by 111.4%, the polyphenol content by 32.5%, the flavone content by 16.4%, and the total amino acid content by 95.4%. Scanning electron microscopy revealed that the microscopic morphology of MBE changed from complete and dense blocks to loosely porous shapes after fermentation. After fermentation, the solubility, water-holding capacity, and viscosity significantly increased and the particle size decreased. Moreover, the glucose adsorption capacity (2.1 mmol g-1), glucose dialysis retardation index (75.3%), and α-glucosidase inhibitory (71.4%, mixed reversible inhibition) activity of the fermented MBE (FMBE) were greater than those of the unfermented MBE (0.99 mmol g-1, 32.1%, and 35.1%, respectively). The FMBE presented better cholesterol and sodium cholate (SC) adsorption properties and the adsorption was considered inhomogeneous surface adsorption.

CONCLUSION

Fermentation increased the bioactive component content and improved the physicochemical properties of MBE, thereby improving its hypoglycemic and hypolipidemic properties. This study not only resolves the problem of millet bran waste but also encourages the development of higher value-added application methods for millet bran. © 2024 Society of Chemical Industry.

Structural characterization and hypoglycemic effect of polysaccharides of Polygonatum sibiricum

Polygonatum sibiricum polysaccharide (PSP) was extracted and purified from raw material obtained from P. sibiricum. The structural features of PSP were investigated by Congo red, circular dichroism spectrum, high-performance gel permeation chromatography, scanning electron microscope, atomic force microscope, ultraviolet spectroscopy, and Fourier transform infrared spectroscopy analysis. In vitro simulations were conducted to investigate the kinetics of PSP enzyme inhibition. Moreover, a type II diabetes mouse model (T2DM) with streptozotocin-induced insulin resistance was established, and the indexes of lipid quadruple, insulin resistance index, oral glucose tolerance (OGTT), organ index, and pancreatic morphology of model mice were measured. The results showed that PSP mainly consists of monosaccharides, such as mannose, glucose, galactose, xylose, and arabinose. It also has a β-glycosidic bond of a pyranose ring and an irregular reticulated aggregated structure with a triple helix. In vitro enzyme inhibition assays revealed that PSP acts as a reversible competitive inhibitor of α-glucosidase and α-amylase. Furthermore, PSP was found to reduce insulin resistance index, increase OGTT and serum insulin levels, decrease free fatty acid content to improve lipid metabolism, and lower glycated serum protein content to enhance glucose metabolism in T2DM mice, thereby leading to a reduction in blood glucose concentration. Additionally, PSP exhibited reparative effects on the damaged liver tissue cells and pancreatic tissue in T2DM mice. The experiment results provide a preliminary basis for the therapeutic mechanism of PSP about type II diabetes and a theoretical reference for application in food and pharmaceutical development.

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.

Antifreeze Polysaccharides from Wheat Bran: The Structural Characterization and Antifreeze Mechanism

Exploring a novel natural cryoprotectant and understanding its antifreeze mechanism allows the rational design of future sustainable antifreeze analogues. In this study, various antifreeze polysaccharides were isolated from wheat bran, and the antifreeze activity was comparatively studied in relation to the molecular structure. The antifreeze mechanism was further revealed based on the interactions of polysaccharides and water molecules through dynamic simulation analysis. The antifreeze polysaccharides showed distinct ice recrystallization inhibition activity, and structural analysis suggested that the polysaccharides were arabinoxylan, featuring a xylan backbone with a majority of Araf and minor fractions of Manp, Galp, and Glcp involved in the side chain. The antifreeze arabinoxylan, characterized by lower molecular weight, less branching, and more flexible conformation, could weaken the hydrogen bonding of the surrounding water molecules more evidently, thus retarding the transformation of water molecules into the ordered ice structure.

Functional properties, structural characteristics, and anti-complementary activities of two degraded polysaccharides from strawberry fruits

Two low-molecular-weight polysaccharides (DPSP50 and DPSP70) were obtained using hydrogen peroxide-vitamin C (H2O2-Vc) treatment at 50 °C and 70 °C, respectively. Both DPSP50 and DPSP70 comprised the same six monosaccharides in different ratios, and their molecular weights (Mws) were 640 kDa and 346 kDa, respectively. Functional properties analyses demonstrated that DPSP50 and DPSP70 each had an excellent water holding capacity, oil absorption capacity, and emulsion properties, as well as shear-thinning characteristics and viscoelastic properties. Fourier transform infrared (FT-IR) and nuclear magnetic resonance (NMR) spectroscopic assays confirmed the existence of α-, β-pyranose rings and the same six sugar residues in DPSP50 and DPSP70. The results of Congo red test, scanning electron microscopy (SEM), and X-ray diffraction (XRD) demonstrated that DPSP50 and DPSP70 did not contain triple-helix conformations, but were amorphous aggregates with flake-like shape and rough surface. Additionally, both DPSP50 and DPSP70 showed strong anti-complementary activities through the classical pathway and the alternative pathway. The results support the potential utility of these degraded polysaccharides from strawberry fruits in functional foods and medicines.

Characterization of feruloylated arabinoxylan - acorn starch double network gel composite film and its application in postharvest preservation of Agaricus bisporus

To obtain efficient natural food packaging materials, we utilized acorn starch (AS)-based film strengthened by feruloylated arabinoxylan (FAX) gel and additional retrogradation treatment to extend the shelf life of Agaricus bisporus (A. bisporus). Fourier transform infrared spectroscopy (FT-IR), confocal laser scanning microscopy (CLSM), and scanning electron microscopy (SEM) analyses showed that due to the strong hydrogen bonding between FAX and starch molecules, physical crosslinking occurred between FAX and starch molecules in the composite film, and the microstructure became more compact. Thermogravimetric, tensile strength and swelling degree analyses indicate that the composite film exhibits better thermal stability, mechanical properties, and waterproofing compared to the pure AS film. Consequently, after five days of storage, the moisture content of the A. bisporus packaged with our composite film was 7.53 times and 5.73 times higher than that of the control group and the commercially available PEF group, respectively. Moreover, it delayed the respiration or transpiration of A. bisporus (lower weight loss, relative conductivity, MDA content). This packaging film developed with the objective of eco-friendly and biodegradability has considerable application potential in food and other industries.

Sourcing chitin from exoskeleton of Tenebrio molitor fed with polystyrene or plastic kitchen wrap

In this work we have characterized and compared chitin sourced from exoskeleton of Tenebrio molitor larvae fed with polystyrene or plastic kitchen wrap combined with bran in the ratio 1: 1 with chitin sourced from larvae exoskeleton fed only with bran. Analysis of the frass by ATR-FTIR showed very similar spectra and confirmed degradation of the plastic feed components, while ATR-FTIR analysis of the exoskeleton verified the absence of any plastic residue. Deproteinization followed by demineralization produced 6.78-5.29 % chitin, showing that plastic (polystyrene or plastic kitchen wrap) in the larvae diet resulted in heavier insect exoskeleton, but yielded slightly less chitin, with the lowest value obtained for plastic kitchen wrap in the insect diet. The deacetylation degree of 98.17-98.61 % was determined from measured ATR-FTIR spectra. XRD analysis confirmed the presence of α-chitin with a crystallinity index of 66.5-62 % and crystallite size 4-5 nm. Thermogravimetric analysis showed similar degradation curves for all chitin samples, with two degradation steps. These results show that chitin sourced from exoskeleton of T. molitor larvae fed with plastic (polystyrene or plastic kitchen wrap) and contributing to significant biodegradation of major polluting materials can be a feasible and alternative source of chitin, further promoting a bio-circular economy.

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.

Unveiling the breadmaking transformation: Structural and functional insights into Arabinoxylan

To understand the changes in arabinoxylan (AX) during breadmaking, multi-step enzyme digestion was conducted to re-extract arabinoxylan (AX-B) from AX-fortified bread. Their structural changes were compared using HPSEC, HPAEC, FT-IR, methylation analysis, and 1H NMR analysis; their properties changes in terms of enzymatic inhibition activities and in vitro fermentability against gut microbiota were also compared. Results showed that AX-B contained a higher portion of covalently linked protein while the molecular weight was reduced significantly after breadmaking process (from 677.1 kDa to 15.6 kDa); the structural complexity of AX-B in terms of the degree of branching was increased; the inhibition activity against α-amylase (76.81 % vs 73.89 % at 4 mg/mL) and α-glucosidase (64.43 % vs 58.08 % at 4 mg/mL) was improved; the AX-B group produced a higher short-chain fatty acids concentration than AX (54.68 ± 7.86 mmol/L vs 44.03 ± 4.10 mmol/L). This study provides novel knowledge regarding the structural and properties changes of arabinoxylan throughout breadmaking, which help to predict the health benefits of fibre-fortified bread and achieve precision nutrition.

Understanding Antidiabetic Potential of Oligosaccharides from Red Alga Dulse Devaleraea inkyuleei Xylan by Investigating α-Amylase and α-Glucosidase Inhibition

In this study, the α-glucosidase (maltase-glucoamylase: MGAM) and α-amylase inhibitory properties elicited by xylooligosaccharides (XOSs) prepared from dulse xylan were analysed as a potential mechanism to control postprandial hyperglycaemia for type-2 diabetes prevention and treatment. Xylan was purified from red alga dulse powder and used for enzymatic hydrolysis using Sucrase X to produce XOSs. Fractionation of XOSs produced xylobiose (X2), β-(1→3)-xylosyl xylobiose (DX3), xylotriose (X3), β-(1→3)-xylosyl-xylotriose (DX4), and a dulse XOS mixture with n ≥ 4 xylose units (DXM). The different fractions exhibited moderate MGAM (IC50 = 11.41-23.44 mg/mL) and α-amylase (IC50 = 18.07-53.04 mg/mL) inhibitory activity, which was lower than that of acarbose. Kinetics studies revealed that XOSs bound to the active site of carbohydrate digestive enzymes, limiting access to the substrate by competitive inhibition. A molecular docking analysis of XOSs with MGAM and α-amylase clearly showed moderate strength of interactions, both hydrogen bonds and non-bonded contacts, at the active site of the enzymes. Overall, XOSs from dulse could prevent postprandial hyperglycaemia as functional food by a usual and continuous consumption.

The Regulatory Effect of Huangshui Polysaccharides on Intestinal Microbiota and Metabolites during In Vitro Fermentation

Huangshui polysaccharides (HSPs) have attracted extensive attention recently for their biological activity and physicochemical property. This research investigated the extraction, structural characterization, and prebiotic activity of three different HSPs (HSP40-0, HSP60-0, and HSP80-0) in vitro to reveal the scientific support for the high-value utilization of Huangshui. HSPs were heteropolysaccharide with diverse structures and surface morphologies. Comprehensive analysis was conducted through 16S rRNA gene sequencing and metabolite profiling techniques, and results showed that HSPs had different potentials to regulate the gut microbiota due to their different structures; for instance, both HSP40-0 and HSP80-0 could notably increase the relative abundance of Bacteroidota, whereas HSP60-0 could increase the relative abundance of Phascolarctobacterium. In addition, HSPs upregulated beneficial differential metabolites, especially short-chain fatty acids (SCFAs). Fermentation products containing these metabolites exhibited anti-inflammatory effects on LPS-treated Caco-2 cells. This study will provide reference for exploring the relationship between the natural polysaccharide structure and the prebiotic activity and widen the application of Huangshui.

Response Surface Optimization of Polysaccharides from Jaboticaba (Myrciaria cauliflora [Mart.] O.Berg) Fruits: Ultrasound-Assisted Extraction, Structure Properties, and Antioxidant/Hypoglycemic Activities

Ultrasound-assisted extraction (UAE) method proves to be more effective compared to traditional extraction methods. In the present study, response surface methodology (RSM) was used to determine the optimal process parameters for extracting polysaccharides (U-MCP) from jaboticaba fruit using UAE. The optimum extraction conditions were ultrasonic time 70 min, extraction temperature 60 °C, and power 350 W. Under these conditions, the sugar content of U-MCP was 52.8 %. The molecular weights of the ultrasound-assisted extracted U-MCP ranged from 9.52×102 to 3.27×103  Da, and consisted of five monosaccharides including mannose, galacturonic acid, glucose, galactose, and arabinose. Moreover, in vitro antioxidant and hypoglycaemic assay revealed that U-MCP has prominent anti-oxidant activities (1,1-diphenyl-2-picryl-hydrazyl (DPPH) radicals, hydroxyl radicals and 2,2'-Azinobis (3-ethylbenzothiazoline-6-sulfonic Acid Ammonium Salt) (ABTS) radicals scavenging activities) and hypoglycemic activities (α-amylase and α-glucosidase inhibition activities).

Structural characterization, antioxidant and antibacterial activity of three pectin polysaccharides from blueberry

In this study, three pectin polysaccharides BP1, BP2 and BP3, were purified from blueberries. The weight-average molecular weight (Mw) of BP1, BP2, and BP3 were detected to be 9.027 × 104, 9.313 × 104, and 1.223 × 106 Da, respectively. The structures of the three pectin polysaccharides were characterized and compared based on the results of molecular weight, monosaccharide composition, GC-MS and NMR analysis. Structural characterization revealed that BP1, BP2, and BP3 all contain homogalacturonan (HG) and rhamnogalacturonan I (RG-I) domains, and the rhamnose residues in RG-I domains are substituted at C-4 with side chains such as araban and galactosan. BP2 had the highest degree of esterification and HG domain ratio, followed by BP3 and BP1. In addition, BP1, BP2 and BP3 showed great antioxidant and antibacterial activities, and could destroy the cell membrane of Staphylococcus aureus and Escherichia coli. Moreover, the better DPPH and ABTS free radical scavenging and antibacterial activities of BP1 and BP2 than BP3 might be related to their lower molecular weight. The results of this study will provide essential information for the structure-activity relationship of pectin polysaccharides and research basis for development and application of blueberry pectin polysaccharides.

Anti-diabetic effect of red quinoa polysaccharide on type 2 diabetic mellitus mice induced by streptozotocin and high-fat diet

The purpose of this study was to explore the mechanism of red quinoa polysaccharide (RQP) in alleviating type 2 diabetes (T2D) through in vivo and in vitro experiments. Results of HPLC and FITR showed that RQP was a complex polysaccharide and contained more glucose, galactose and acarbose. In vitro experiments, RQP showed strong antioxidant capacity and inhibition on α-amylase and α-glucosidase. In vivo experiments, RQP was proved to induce a significant improvement of diabetes after 4 weeks of ingestion, including the abilities of lowering blood glucose, regulating lipid metabolism, anti-oxidation and promoting secretion of SCFAs. Furthermore, 16S rRNA study demonstrated that RQP transformed the intestinal microbiota composition in diabetic mice, decreased the abundance of norank_f_Muribaculaceae and Lachnospiraceae_NK4A136_group, and increased the relative abundance of Akkermansia, unclassified_f_Lachnospiraceae, norank_f_Eubacterium_coprostanoligenes_group, unclassified_f_Atopobiaceae and norank_f_Lachnospiraceae. The biosynthetic pathways, metabolic pathways and intestinal microbiome phenotypes in mice also changed accordingly. In conclusion, this study suggests that RQP can inhibit the development of diabetes by correcting the imbalance of intestinal flora.

Exploring the efficacy of various wheat bran extracts in promoting burn wound healing: A comparative analysis

ETHNOPHARMACOLOGICAL RELEVANCE

Although burn wound management in medical practice has improved, the challenge still exists and demands multidisciplinary participation. Wheat has been extensively used as a remedy of different skin conditions especially burns in almost all parts of Italy. However, the mechanism is still unclear.

AIM OF THE STUDY

To examine the effects of different wheat bran extracts on the healing of burn wound estimated grossly, histopathologically, and immunologically.

MATERIALS AND METHODS

Wistar male rats were divided into 5 groups; (control) saline treated group, Mebo (Moist Exposed Burn Ointment), cold-water extract, hot-water extract and methanolic extract groups. After the burn, four groups from the experimental groups were treated with Mebo, cold-water extract, hot-water extract and methanolic extract, respectively, but the negative-control group was treated daily with saline only. The observation was made along days 0, 5, 9, 13, 17 and 21. At the end of the study, rats were sacrificed, and blood samples were collected for biochemical and cytokines estimation in addition to wound samples were collected for histopathological and immunohistochemical studies.

RESULTS

The histopathological examination showed that the inflammation was significantly decreased in all extract-treated groups when compared with saline and Mebo-treated groups. Epithelial tissue and granulation tissue formation most significantly appeared in the cold water extract-treated group.

CONCLUSIONS

Cold water and methanolic extract groups showed the most rapid and effective healing of the burn wound. Particularly the cold-water extract, due to the sufficient concentration of zinc and phenolic components.

Fine structure and hypoglycemic effect of a galactoglucan from the bulbs of Lanzhou lily

The present research aimed to further identify the fine structure, morphology, and thermal behaviors of a galactoglucan BHP-2 derived from Lanzhou lily bulbs through partial acid hydrolysis, methylation, 2D NMR (1H1H COSY, HSQC, and HMBC), scanning electron microscopy (SEM) and thermogravimetric-differential thermal analysis (TG-DTA). Additionally, the study assessed the potential in vitro hypoglycemic effect of BHP-2 by examining its inhibitory effect on α-glucosidase and α-amylase. The results indicated that the main backbone composition of BHP-2 consisted of →4)-α-D-Glcp-(1→, →3)-β-D-Glcp-(1 → and →6)-β-D-Galp-(1→, while the side chain composition predominantly featured →4)-α-D-Glcp-(1→, →3,5)-α-L-Araf-(1 → and →3)-β-D-Galp-(1→, attached to the C-2 and/or C-3 positions of →4)-α-D-Glcp-(1→. Terminal residues consisted of α-D-Glcp-(1 → and β-L-Araf-(1→. BHP-2 exhibited excellent thermal stability, with a microscopic surface characterized by tightly packed sheets and numerous spiral depressions, which might contribute to its remarkable in vitro hypoglycemic effect. BHP-2 showed competitive inhibition of α-amylase and mixed non-competitive inhibition of α-glucosidase, with respective IC50 values of 0.31 and 0.18 mg/mL, closely resembling to those of acarbose (0.27 and 0.12 mg/mL). These findings suggested that BHP-2 had potential as an additive for glycemic intervention.

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.

Structural property of extractable proteins and polysaccharides in wheat bran following a dual-enzymatic pretreatment and corresponding functionality

The current study applied dual-enzymatic treatment via alcalase and Bacillus velezensis hydrolase for enhancing extraction of proteins and polysaccharides from wheat bran and modifying their corresponding structure. Results indicated the aqueous extract by enzymatic pretreatment (referred as EHWB) had an increased content of soluble substance, in which 18.5 % increased for carbohydrates and 11.4 % increased for proteins in the extract compared to the aqueous extract without enzymes (labeled as AEWB). Furthermore, compositions with lower molecular weight of 130 kDa and < 21.1 kDa for polysaccharides and proteins, respectively, were found in EHWB. Interestingly, EHWB had a twice higher radicals scavenging than that of AEWB, and digestive property indicated EHWB had a greater peptides production although glucose release was lower in gastric phase. Importantly, this is the first study to reveal that gut microbiota fermentation of EHWB resulted in faster generation of short-chain fatty acids at initial fermentation stage (6 h), followed a higher generation of butyrate at final fermentation stage (24 h). This fermentation property might be associated with its presence of lower molecular weight substrates and even the changes in the molecular structure induced by the enzymes. This study highlights a novel approach for developing a value-added product from wheat bran.

A review on the hypoglycemic effect, mechanism and application development of natural dietary polysaccharides

Diabetes mellitus (DM) as one chronic metabolic disease was greatly increased over recent decades. The major agents treating diabetes have noticeable side effects as well as the tolerability problems. The bioactive dietary polysaccharides from abundant natural resources exhibit good hypoglycemic effect with rare adverse effects, which might serve as a candidate to prevent and treat diabetes. However, the correlations between the hypoglycemic mechanism of polysaccharides and their structure were not mentioned in several studies, what's more, most of the current hypoglycemic studies on polysaccharides were based on in vitro and in vivo experiments, and there was a lack of knowledge about the effects in human clinical trials. The aim of this review is to discuss recent literature about the variety of dietary polysaccharides with hypoglycemic activity, as well the mechanism of action and the structure-function relationship are highlighted. Meanwhile, the application of dietary polysaccharides in functional foods and clinical medicine are realized with an in-depth understanding. So as to promote the exploration of dietary polysaccharides in low glycemic healthy foods or clinical medicine to prevent and treat diabetes.

Lowering glycemic levels via gastrointestinal tract factors: the roles of dietary fiber, polyphenols, and their combination

Dietary fiber (DF) and polyphenols (DP) are typical blood sugar-lowering components, and both play distinct yet interconnected roles in exerting their blood sugar-lowering effects. We comprehensively summarized the single and combined effects of DF and DP on blood glucose homeostasis through regulating the relevant factors in the upper gastrointestinal tract (UGT) and lower gastrointestinal tract (LGT). In the UGT, DF slowed down glucose metabolism by enhancing digesta viscosity and hindering enzyme-substrate interaction. DP primarily targeted enzymes and substrates. When combined, DP enhanced the adsorption capacity of DF for glucose. DF weakened DP's inhibitory effect on enzymes. Both DF and DP disrupted glucose intestinal uptake via physical or genomic modulation, but the co-consumption of DF and DP demonstrated a lower inhibitory effect on glucose uptake than DP alone. In the LGT, DF and DP showed synergistic or antagonistic effects on gut microbiota. Remarkably, whole foods exhibited potent prebiotic effects due to their compound-rich matrix, potentially enhancing glucose homeostasis and expanding dietary options for glucose regulation research.

Structure and Antidiabetic Activity of a Glycoprotein from Porphyra haitanensis

A novel antidiabetic glycoprotein (PG) was isolated and purified from Porphyra haitanensis, and its structure and inhibiting activity on α-amylase and α-glucosidase were analyzed. The purity of the PG was 95.29 ± 0.21%, and its molecular weight was 163.024 ± 5.55 kDa. The PG had a tetramer structure with α- and β-subunits, and it contained 54.12 ± 0.86% protein (with highly hydrophobic amino acids) and 41.19% ± 0.64% carbohydrate (composed of galactose). The PG was linked via an O-glycosidic bond, exhibiting an α-helical structure and high stability. In addition, the PG inhibited the activities of α-amylase and α-glucosidase, by changing the enzyme's structure toward the PG's structure in a noncompetitive inhibition mode. Molecular docking results showed that the PG inhibited α-amylase activity by hydrophobic interaction, whereas it inhibited α-glucosidase activity by hydrogen bonds and hydrophobic interaction. Overall, the PG was linked to polysaccharides via O-glycosidic bonds, showing an α-helical configuration and a hydrophobic effect, which altered the configuration of α-amylase and α-glucosidase and exerted hypoglycemic activity. This study provides insights into analyzing the structure and antidiabetic activity of glycoproteins.

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.

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.

Functional Characterization and Toxicity of Pectin from Red Chilto Fruit Waste (Peels)

BACKGROUND

Food and agricultural wastes constitute a rich source of functional ingredients for the food, pharmaceutical, and cosmetic industries. In this context, by-products from the red variety of Solanum betaceum fruits (chilto) from Northwestern Argentina are suitable sources for pectin extraction.

METHODS

In this study, pectin from the peels of red chilto fruits was extracted and characterized.

RESULTS

The recovery yield of red chilto peel pectin was about 24%, and it was co-extracted with 40.0 mg phenolic compounds, 6.5 mg anthocyanins, and 4.7 g proteins per 100 g of pectin. The pectin obtained from red chilto showed proper technological functionality displaying water and oil holding capacities of 4.2 and 2.0%, respectively, an emulsifying capacity of 83%, emulsion stability of 87.5%, foaming capacity of 21.1%, and foaming stability of 79.1%. The pectin displayed antioxidant activity with the ability to scavenge ABTS radical, superoxide anion, and H₂O₂. The polysaccharide exhibited in vitro hypoglycemic potential and inhibited the α-amylase enzyme, retarded glucose diffusion, and improved the cellular uptake of glucose in a Saccharomyces cerevisiae model. The extract was non-toxic on acute toxicity tests.

CONCLUSIONS

Red chilto pectin showed potential as a new and safe functional ingredient for the design of foods, health products, and cosmetics.

Structure characterization and biological activities evaluation of two hetero-polysaccharides from Lepista nuda: Cell antioxidant, anticancer and immune-modulatory activities

Polysaccharides LNP-1 and LNP-2 were extracted and purified from Lepista nuda, and their structural characteristics and biological activities were evaluated. The molecular weights of LNP-1 and LNP-2 were determined to be 16,263 Da and 17,730 Da, respectively. The monosaccharide composition analysis showed that LNP-1 and LNP-2 were composed of fucose, mannose, glucose, and galactose in a molar ratio of 1.00:2.42:1.09:4.04 and 1.00:2.39:1.61:4.23, respectively. The structure analysis revealed that these two polysaccharides were mainly composed of T-Fuc, T-Man, T-Glc, 1,6-Glc 1,6-Gal, and 1,2,6-Man, 1,2,6-Gal. Additionally, LNP-2 contained an additional 1,4-Glc glycosidic linkage in comparison to LNP-1. Both LNP-1 and LNP-2 exhibited anti-proliferation effects on A375 cells, but not on HepG2 cells. Furthermore, LNP-2 showed better cellular antioxidant activity (CAA) than LNP-1. RT-PCR results indicated that LNP-1 and LNP-2 could induce macrophages to secrete immune-modulatory factors NO, IL-6, and TNF-α by regulating their mRNA expression. Overall, this study provides a theoretical basis for the further development of the structure-function relationship of polysaccharides from L. nuda.

Structure Characterization, In Vitro Antioxidant and Anti-Tumor Activity of Sulfated Polysaccharide from Siraitia grosvenorii

From Siraitia grosvenorii, a natural polysaccharide named SGP-1 was discovered, and its purity was determined to be 96.83%. Its structure is a glucan with 4-, 6- and 4,6-linked glucose units. In this paper, the sulfated derivative S-SGP of SGP-1 was prepared by the chlorosulfonic acid method. The sulfated derivatives were analyzed by Fourier transform infrared spectroscopy (FT-IR), gel permeation chromatography (GPC), and scanning electron microscopy (SEM). The degree of substitution (DS) of the polysaccharide is 0.62, and the weight average molecular weight (Mw) is 1.34 × 10⁴ Da. While retaining the morphological characteristics of polysaccharides, S-SGP appeared a large number of spherical structures and strong intermolecular forces. The in vitro activity study of S-SGP showed that the sulfated derivatives had the ability to scavenge DPPH radicals, hydroxyl radicals and superoxide anions, and the scavenging power tended to increase with the increase in polysaccharide concentration. It can inhibit the growth of human hepatoma cells (HepG2), human breast cancer cells (MDA-MB-231) and human non-small cell lung cancer cells (A549) in vitro. In addition, the treatment of A549 cells with sulfuric acid derivatives can decrease the mitochondrial membrane potential, induce apoptosis, and alter the expression of apoptosis-related mRNA and protein.

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.

Structural characterization, α-glucosidase inhibitory activity and antioxidant activity of neutral polysaccharide from apricot (Armeniaca Sibirica L. Lam) kernels

Screening for α-glucosidase inhibitors and antioxidants from natural sources that could reduce postprandial glucose in diabetic patients and reduce oxidative stress had attracted considerable interest. In this study, a neutral polysaccharide (AP-1) with a triple helix structure was isolated and purified from the residue of apricot (Armeniaca sibirica L. Lam.) kernels by using DEAE-52 and Sephadex G-100 columns. The molecular weight of AP-1 was 23.408 kDa and consisted mainly of glucose with trace amounts of arabinose, galactose, and mannose, which had molar percentages of 98.48, 0.63, 0.62 and 0.27 %, respectively. The main chain of AP-1 was composed of →4)-α-D-Glcp-(1 → interlinked, and α-D-Glcp-(1 → was attached as a branched chain at the O-6 position of →4,6)-α-D-Glcp-(1→. In addition, AP-1 exhibited stronger α-glucosidase inhibition and free radical scavenging ability compared to crude polysaccharides. Therefore, AP-1 could be used as a potential natural hypoglycemic agent and antioxidant in the treatment of diabetes mellitus.

Fermented Wheat Bran Polysaccharides Improved Intestinal Health of Zebrafish in Terms of Intestinal Motility and Barrier Function

Intestinal barrier dysfunction and gut microbiota disorders have been associated with various intestinal and extraintestinal diseases. Fermented wheat bran polysaccharides (FWBP) are promising natural products for enhancing the growth performance and antioxidant function of zebrafish. The present study was conducted, in order to investigate the effects of FWBP on the intestinal motility and barrier function of zebrafish, which could provide evidence for the further potential of using FWBP as a functional food ingredient in the consideration of gut health. In Experiment 1, the normal or loperamide hydrochloride-induced constipation zebrafish larvae were treated with three concentrations of FWBP (10, 20, 40 μg/mL). In Experiment 2, 180 one month-old healthy zebrafish were randomly divided into three groups (six replicates/group and 10 zebrafish/tank) and fed with a basal diet, 0.05% FWBP, or 0.10% FWBP for eight weeks. The results showed that FWBP treatment for 6 h can reduce the fluorescence intensity and alleviate constipation, thereby promoting the gastrointestinal motility of zebrafish. When compared with control group, zebrafish fed diets containing FWBP showed an increased villus height (p < 0.05), an up-regulated mRNA expression of the tight junction protein 1α, muc2.1, muc5.1, matrix metalloproteinases 9 and defensin1 (p < 0.05), an increased abundance of the phylum Firmicutes (p < 0.05), and a decreased abundance of the phylum Proteobacteria, family Aeromonadaceae, and genus Aeromonas (p < 0.05). In addition, 0.05% FWBP supplementation up-regulated the intestinal mRNA expression of IL-10 and Occludin1 (p < 0.05), enhanced the Shannon and Chao1 indexes (p < 0.05), and increased the abundance of Bacteroidota and Actinobacteriota at the phylum level (p < 0.05). Additionally, 0.1% FWBP supplementation significantly improved the villus height to crypt depth ratio (p < 0.05) and increased the mRNA expression of IL-17 (p < 0.05). These findings reveal that FWBP can promote the intestinal motility and enhance the intestinal barrier function, thus improving the intestinal health of zebrafish.