Fractionation, preliminary structural characterization and prebiotic activity of polysaccharide from the thin stillage of distilled alcoholic beverage

Size exclusion chromatography and asymmetrical flow field-flow fractionation for structural characterization of polysaccharides: A comparative review

Natural polysaccharides exhibit a wide range of biological activities, which are closely related to their structural characteristics, including their molecular weight distribution, size, monosaccharide composition, glycosidic bond types and spatial conformation, etc. Size exclusion chromatography (SEC) and asymmetrical flow field-flow fractionation (AF4), as two potent separation techniques, both harbor potential for continuous development and enhancement. This manuscript reviewed the fundamental principles and separation applications of SEC and AF4. The structural information and spatial conformation of polysaccharides can be obtained using SEC or AF4 coupled with multiple detectors. In addition, this manuscript elaborates in detail on the shear degradation of samples such as polysaccharides separated by SEC. In addition, the abnormal elution that occurs during the application of the two methods is also discussed. Both SEC and AF4 possess considerable potential for ongoing development and refinement, thereby offering increased possibilities and opportunities for polysaccharide separation and characterization.

Polysaccharides extracted from larvae of Lucilia sericata ameliorated ulcerative colitis by regulating the intestinal barrier and gut microbiota

Pest management technology has been a promising bioconversion method for waste resource utilization. Unlike many pests that consume waste, the larvae of Lucilia sericata, also known as maggots, have many outstanding advantages as following: with their strong adaption to environment and not easily infected and exhibiting a medicinal nutritional value. Herein, the potential efficacies of maggot polysaccharides (MP), as well as their underlying mechanisms, were explored in Dextran sulfate sodium (DSS)-induced colitis mice and TNF-α-elicited Caco-2 cells. We extracted two bioactive polysaccharides from maggots, MP-80 and MP-L, whose molecular weights were 4.25 × 103 and 2.28 × 103 g/mol, respectively. MP-80 and MP-L contained nine sugar residues: 1,4-α-Arap, 1,3-β-Galp, 1,4,6-β-Galp, 1,6-α-Glcp, 1-α-Glcp, 1,4-β-Glcp, 1-β-Xylp, 1,2-α-Manp, and 1-β-Manp. We demonstrated that MP-80 and MP-L significantly ameliorated DSS-induced symptoms and histopathological damage. Immuno-analysis revealed that compared with MP-L, MP-80 could better restore intestinal barrier and reduced inflammation by suppressing NLRP3/NF-κB pathways, which might be attributed to its enriched galactose fraction. Moreover, 16S rRNA sequencing revealed that MP-80 and MP-L both improved the dysbiosis and diversity of gut microbiota and acted on multiple microbial functions. Our study sheds new light on the possibility of using maggot polysaccharides as an alternative therapy for colitis.

Effects of In Vitro Fermentation of Polysialic Acid and Sialic Acid on Gut Microbial Community Composition and Metabolites in Healthy Humans

The influence of polysialic acid (PSA) and sialic acid (SA) on the gut microbial community composition and metabolites in healthy humans was investigated using a bionic gastrointestinal reactor. The results indicated that PSA and SA significantly changed the gut microbiota and metabolites to different degrees. PSA can increase the relative abundances of Faecalibacterium and Allisonella, whereas SA can increase those of Bifidobacterium and Megamonas. Both can significantly increase the content of short-chain fatty acids. The results of metabolome analysis showed that PSA can upregulate ergosterol peroxide and gallic acid and downregulate the harmful metabolite N-acetylputrescine. SA can upregulate 4-pyridoxic acid and lipoic acid. PSA and SA affect gut microbiota and metabolites in different ways and have positive effects on human health. These results will provide a reference for the further development of PSA- and SA-related functional foods and health products.

A Comparative Study of the Effects of Whole Cereals and Refined Cereals on Intestinal Microbiota

Cereals are one of the most important foods on which human beings rely to sustain basic life activities and are closely related to human health. This study investigated the effects of different steamed buns on intestinal microbiota. Three steamed buns were prepared using refined flour (RF), 1:1 mixed flour (MF), and whole wheat flour (WF). In vitro digestion simulations were conducted using a bionic gastrointestinal reactor (BGR) to examine their influence on intestinal microbiota. The results showed that at 0.5% addition, butyric acid and short-chain fatty acids in WF were significantly different from those in RF and MF (p < 0.05). WF also promoted the proliferation of beneficial microbiota, such as Megamonas and Subdoligranulum. At 0.5%, 1.0%, and 1.5% additions of WF, acetic acid and short-chain fatty acids at 1.5% WF increased by 1167.5% and 11.4% from 0.5% WF, respectively, and by 20.2% and 7.6% from 1.0% WF, respectively. WF also promoted the proliferation of Bifidobacterium, Lactobacillus, and Bacteroides and inhibited the growth of pathogenic microbiota, such as Streptococcus, Enterococcus, and Klebsiella. These findings support the consumption of whole cereals and offer insights into the development of new functional foods derived from wheat.

Antioxidant and anti-inflammatory properties of an aminoglycan-rich exopolysaccharide from the submerged fermentation of Bacillus thuringiensis

Proteins from Bacillus thuringiensis are widely used as biopesticides but little is known about its exopolysaccharides. The exopolysaccharide BPS-2 was extracted from B. thuringiensis IX-01 after high-cell-density fermentation. BPS-2 is a heteropolysaccharide (molecular weight 29.36 kDa) composed of D-galactosamine, arabinose, glucosamine, glucose, and mannose in molar ratios 5.53: 1.77:4.74:3.24:1. In vitro upper gastrointestinal simulations showed that BPS-2 has strong anti-digestive capacity, with scavenging of DPPH, hydroxyl, ABTS, and superoxide anions radicals of 31.34 ± 1.67 %, 32.43 ± 3.01 %, 34.31 ± 2.12 %, and 48.53 ± 3.55 %, respectively, after BPS-2 entered the colon. It significantly inhibited production of lipopolysaccharide-induced nitric oxide and multiple pro-inflammatory cytokines and had proliferative effects on RAW 264.7 cells. BPS-2 inhibited malondialdehyde secretion and elevated activities of glutathione peroxidase, superoxide dismutase, and total antioxidants, significantly improving the antioxidant status of inflammation model cells. This first report of the in vitro anti-inflammation and antioxidant properties of BPS-2 from B. thuringiensis provides a basis for biopharmaceutical applications.