Ultrasound-assisted hydrogen peroxide-ascorbic acid method to degrade sweet corncob polysaccharides can help treat type 2 diabetes via multiple pathways in vivo

Preliminary characterization of Ramaria botrytoides polysaccharide RB-P1-1 and analysis of its hypoglycemic effects by altering the gut microbiota and metabolites in mice with type 2 diabetes mellitus

Gut microbiota has a symbiotic relationship with the host and is closely linked to the development of type 2 diabetes mellitus (T2DM). Polysaccharides are natural bioactive compounds with beneficial effects on T2DM; however, the mechanisms underlying their effects remain unclear. This study investigated the hypoglycemic effects of a purified polysaccharide, RB-P1-1, from Ramaria botrytoides and assessed its association with gut microbiota and metabolite changes using 16S rDNA sequencing and liquid chromatography-mass spectrometry, respectively. Hypoglycemic effects were evaluated after microbial community restoration via fecal microbiota transplantation. RB-P1-1 significantly improved hyperglycemia profiles and reshaped gut microbiota, increasing the abundance of Alistipes, Bacteroides, Ruminococcus, Odoribacter, Akkermansia, and Turicibacter. RB-P1-1 modulated microbiota metabolites associated with hypoglycemic effects, including pyridoxamine, L-histidine, quercetin, 3-phosphonopropionic acid, oleoylethanolamide, 3-ketocholanic acid, 4-phenylbutyric acid, LysoPC(P-16:0/0:0), LysoPC(18:2), and short-chain fatty acids, and altered various metabolic pathways involved in T2DM development. Gut microbiota that showed altered abundance were correlated with metabolites that showed altered concentration. Gut microbiota isolated from the RB-P1-1-treated group alleviated the symptoms associated with T2DM. These results suggest RB-P1-1 is an effective active ingredient in the treatment of T2DM by modulating gut microbiota and metabolites.

Structural characterization, antioxidant activity, and fermentation characteristics of Flammulina velutipes residue polysaccharide degraded by ultrasonic assisted H2O2-Vc technique

Adhere to the concept of low-carbon environmental protection and turning waste into treasure, polysaccharides from Flammulina velutipes residue polysaccharide (FVRP) has been developed and possesses diverse bioactivities, comprising antioxidant, hypoglycemic, and relieving heavy metal damage, which still has the disadvantages of high molecular weight and low bioavailability. The current work is the first to prepare a degraded polysaccharide (FVRPV) from FVRP by ultrasonic assisted H2O2-Vc technique in order to reduce its molecular weight, thereby improving its activity and bioavailability. Our results found that the molecular weight and average particle size were declined, but the monosaccharide composition and characteristic functional group types of FVRPV had no impact. The structural changes of polysaccharides analyzed by XRD, Congo Red test, I2-KI, SEM, and methylation analysis indicated that the surface morphology and glycosidic bond composition of FVRPV possessed longer side chains and a greater number of branches with an amorphous crystal structure devoid of a triple helix configuration, and had experienced notable alterations after ultrasonic assisted H2O2-Vc treatment. Meanwhile, the in vitro antioxidant capacity of FVRPV had significantly increased compared to FVRP, implying ultrasonic assisted H2O2-Vc technique maybe a effective method to enhance the bioactivity of polysaccharides. In addition, the content of polysaccharide, reducing sugar, and uronic acid in FVRPV was significantly decreased, but antioxidant capacity of fermentation broth was stronger by in vitro human fecal fermentation. The 16S rDNA sequencing data displayed that FVRPV can enrich probiotics and reduce the abundance of pathogenic bacteria through different metabolic pathways mediated by gut microbiota, thereby exerting its potential probiotic effects. The interesting work provides a novel degraded polysaccharide by ultrasonic assisted H2O2-Vc technique, laying a foundation for developing FVRPV as a new antioxidant and prebiotic.

Pectic polysaccharides from Tartary buckwheat sprouts: Effects of ultrasound-assisted Fenton treatment and mild alkali treatment on their physicochemical characteristics and biological functions

Buckwheat sprouts are rich in pectic polysaccharides, which possess numerous health-improving benefits. However, the precise structure-activity relationship of pectic polysaccharides from Tartary buckwheat sprouts (TP) is still scant, which ultimately restricts their applications in the food industry. Hence, both ultrasound-assisted Fenton treatment (UAFT) and mild alkali treatment (MATT) were utilized for the modification of TP, and then the effects of physicochemical characteristics of original and modified TPs on their bioactivities were assessed. Our findings reveled that the UAFT treatment could precisely reduce TP's molecular weight, with the levels decreased from 8.191 × 104 Da to 0.957 × 104 Da. Meanwhile, the MATT treatment could precisely reduce TP's esterification degree, with the values decreased from 28.04 % to 4.72 %. Nevertheless, both UAFT and MATT treatments had limited effects on the backbone and branched chain of TP. Moreover, our findings unveiled that the UAFT treatment could notably promote TP's antioxidant, antiglycation, and immunostimulatory effects, while remarkedly reduce TP's anti-hyperlipidemic effect, which were probably owing to that the UAFT treatment obviously reduced TP's molecular weight. Additionally, the MATT treatment could also promote TP's immunostimulatory effect, which was probably attributed to that the MATT treatment significantly decreased TP's esterification degree. Interestingly, the MATT treatment could regulate TP's antioxidant and antiglycation effects, which was probably attributed to that the MATT treatment simultaneously reduced its esterification degree and bound phenolics. Our findings are conducive to understanding TP's structure-activity relationship, and can afford a scientific theoretical basis for the development of functional or healthy products based on TPs. Besides, the UAFT treatment can be a promising approach for the modification of TP to improve its biological functions.

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

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

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

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

Polysaccharide from Clitocybe squamulosa: Gel-forming properties and its compound effect with food thickener

To study the gel-forming properties of polysaccharide from the fruiting body of Clitocybe squamulosa (CSFP) and its degradation product (UH-CSFP), the changes in steady-state and dynamic rheological properties of CSFP and UH-CSFP under different conditions (polysaccharide mass fraction, temperature, pH, and salt ion concentration) were studied. Polysaccharides with good gel-forming properties were selected and mixed with common edible thickeners (gelatin, guar gum, and locust bean gum), after which the properties of the composite gel were assessed. The steady-state rheological results showed that CSFP and UH-CSFP were pseudoplastic fluids, their apparent viscosity decreased with increasing temperature, the viscosity was greatest when the pH was 7. The addition of Na+ and Ca2+ could increase the viscosity, and the viscosity of UH-CSFP was lower than that of CSFP at the same mass fraction. The results of dynamic rheology indicated that G´ and G´´ of CSFP and UH-CSFP increased with increasing mass fraction, pH, and ion concentration (0.01 M to 1 M), and G´´ was always smaller than G´ indicating weak gel behavior. The thixotropy-related experimental results showed that the thixotropy ring area of CSFP and UH-CSFP increased with increasing mass fraction, the ring area of CSFP was larger than that of UH-CSFP, and the gel strength of CSFP was greater than that of UH-CSFP. The results of CSFP and three types of edible gels showed that the composite gels were pseudoplastic fluids, and their apparent viscosity was ranked (in descending order) as follows: guar bean gum, locust bean gum, and gelatin. The addition of CSFP improved the gel-forming properties of guar gum but did not significantly improve the gel properties of locust bean gum and gelatin. This study provides a theoretical basis for the selection of processing methods and the application of polysaccharides.