Isolation, characterisation and complement fixation activity of acidic polysaccharides from Argemone mexicana used as antimalarials in Mali

Monosaccharide composition and glycosidic linkages analysis by ultra high performance liquid chromatography-triple quadrupole tandem mass spectrometry-Case study of plant polysaccharides

Monosaccharide composition and glycosidic linkages analysis are essential for the structural characterization and biological activity research of polysaccharides. To simplify the analysis steps and improve detection efficiency, this study developed monosaccharide compositions and glycosidic linkages detection methods based on UPLC-QqQ-MS/MS, and established a plant polysaccharide glycosidic linkages library. Furthermore, the detailed analysis process of monosaccharide compositions and glycosidic linkages was presented through a plant polysaccharide (Chinese bayberry wine polysaccharide, CPW) example. The results showed that the monosaccharide analysis method could identify and quantify 20 monosaccharides within 13 min by 6 chromatograms. By this method, 7 monosaccharides were detected in CPW, which was consistent with previous results obtained using ion chromatography. Meanwhile, the UPLC-QqQ-MS/MS based method could analyze 112 glycosidic linkages of 9 plant monosaccharides within 30 min, and the results were distributed on 11 chromatograms. According to the approach, 44 different glycosidic linkages were identified in CPW. Based on Congo red assay and molecular weight as well as our findings of monosaccharide composition and glycosidic linkages, we proposed that CPW may consist of two distinct sugar chains: One composed of 1-2,4-Rha, 1-3,4-GalA, and 1-F-Ara, and the other composed of 1-3,4-Gal, 1-4-Gal, 1-3,4,6-Gal, and 1-F-Ara.

Structural characterization and mechanisms of macrophage immunomodulatory activity of a novel polysaccharide with a galactose backbone from the processed Polygonati Rhizoma

A purified polysaccharide with a galactose backbone (SPR-1, Mw 3,622 Da) was isolated from processed Polygonati Rhizoma with black beans (PRWB) and characterized its chemical properties. The backbone of SPR-1 consisted of [(4)-β-D-Galp-(1]9 → 4,6)-β-D-Galp-(1 → 4)-α-D-GalpA-(1 → 4)-α-D-GalpA-(1 → 4)-α-D-Glcp-(1 → 4,6)-α-D-Glcp-(1 → 4)-α/β-D-Glcp, with a branch chain of R1: β-D-Galp-(1 → 3)-β-D-Galp-(1→ connected to the →4,6)-β-D-Galp-(1→ via O-6, and a branch chain of R2: α-D-Glcp-(1 → 6)-α-D-Glcp-(1→ connected to the →4,6)-α-D-Glcp-(1→ via O-6. Immunomodulatory assays showed that the SPR-1 significantly activated macrophages, and increased secretion of NO and cytokines (i.e., IL-1β and TNF-α), as well as promoted the phagocytic activities of cells. Furthermore, isothermal titration calorimetry (ITC) analysis and molecular docking results indicated high-affinity binding between SPR-1 and MD2 with the equilibrium dissociation constant (K D) of 18.8 μM. It was suggested that SPR-1 activated the immune response through Toll-like receptor 4 (TLR4) signaling and downstream responses. Our research demonstrated that the SPR-1 has a promising candidate from PRWB for the TLR4 agonist to induce immune response, and also provided an easily accessible way that can be used for PR deep processing.

Ultrasonic-assisted extraction of polysaccharide from Paeoniae Radix alba: Extraction optimization, structural characterization and antioxidant mechanism in vitro

Paeoniae Radix alba is used in Traditional Chinese Medicine for the treatment of gastrointestinal disorders, immunomodulatory, cancer, and other diseases. In the current study, the yield of Paeoniae Radix alba polysaccharide (PRP) was significantly increased with optimal ultrasound-assisted extraction compared to hot water extraction. Further, an acidic polysaccharide (PRP-AP) was isolated from PRP after chromatographic separation and was characterized as a typical pectic polysaccharide with side chains of arabinogalactans types I and II. Moreover, it showed antioxidant effects on LPS-induced damage on IPEC-J2 cells determined by qRT-PCR and ELISA, including decreasing the pro-inflammatory factors' expressions and increasing the antioxidant enzymes activities, which was shown to be related to the Nrf2/Keap1 pathway modulated by PRP-AP. The metabolites change (such as itaconate, cholesterol sulfate, etc.) detected by untargeted metabolomic analysis in cells was also shown to be modulated by PRP-AP, and these metabolites were further utilized and protected cells damaged by LPS. These results revealed the cellular active mechanism of the macromolecular PRP-AP on protecting cells, and supported the hypothesis that PRP-AP has strong benefits as an alternative dietary supplement for the prevention of intestinal oxidative stress by modulating cellular metabolism.

Bioactive polysaccharides in different plant parts of Aconitum carmichaelii

BACKGROUND

Aconitum carmichaelii is an industrially cultivated medicinal plant in China and its lateral and mother roots are used in traditional Chinese medicine due to the presence of alkaloids. However, the rootlets and aerial parts are discarded after collection of the roots, and the non-toxic polysaccharides in this plant have attracted less attention than the alkaloids and poisonous features. In this study, five neutral and 14 acidic polysaccharide fractions were isolated systematically from different plant parts of A. carmichaelii, and their structural features and bioactivity were studied and compared.

RESULTS

The neutral fraction isolated from the rootlets differed from those isolated from the lateral and mother roots. It consisted of less starch and more possible mannans, galactans, and/or xyloglucans, being similar to those of the aerial parts. Pectic polysaccharides containing homogalacturonan and branched type-I rhamnogalacturonan (RG-I) were present in all plant parts of A. carmichaelii. However, more arabinogalactan (AG)-II side chains in the RG-I backbone were present in the aerial parts of the plants, while more amounts of arabinans were found in the roots. Various immunomodulatory effects were observed, determined by complement fixation activity and anti-inflammatory effects on the intestinal epithelial cells of all polysaccharide fractions.

CONCLUSION

This study highlighted the diversity of polysaccharides present in A. carmichaelii, especially in the unutilized plant parts, and showed their potential medicinal value. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Effects of hazelnut soluble dietary fiber on lipid-lowering and gut microbiota in high-fat-diet-fed rats

Hazelnut is one of the most popular nuts in the world, rich in nutrients and various active substances. In this study, soluble dietary fiber (SDF) was extracted from hazelnut kernels, and its physicochemical properties and absorbability were explored. Hazelnut-SDF exhibited ideal water-holding, oil-holding and swelling capacity, and glucose, cholesterol and cholate absorbing ability. Scanning electron microscopy and fourier transform infrared spectroscopy showed that hazelnut-SDF had typical polysaccharide structure of functional groups. The main monosaccharides were identified as arabinose, rhamnose, xylose, ribose, glucuronic acid, mannose and glucose by gas chromatography-mass spectrometry. In high-fat diet rats, hazelnut-SDF could improve serum lipid parameters, inhibit lipid accumulation in liver and adipocytes, and regulate the expression level of liver lipid synthesis-related genes. It also could adjust intestinal short chain fatty acids, promote the composition and structure of intestinal microbiota, and significantly balance the abundance of Alloprevotella, Fusicatenibacter, Lactobacillus, Roseburia, Ruminococcaceae_UCG-005, Ruminococcaceae_UCG-014 and Clostridiales. The results concluded that oral administration of hazelnut-SDF could alleviate hyperlipidemia and obesity, and might serve as a potential functional food ingredient.

Fructus mori polysaccharide alleviates diabetic symptoms by regulating intestinal microbiota and intestinal barrier against TLR4/NF-κB pathway

Fructus mori polysaccharide (FMP) has a variety of biological activities. In this study, the results showed that FMP alleviated hyperglycemia, insulin resistance, hyperlipidemia, endotoxemia, and high metabolic inflammation levels in type 2 diabetic (T2DM) mice. Next, it was found that the above beneficial effects of FMP on diabetic mice were significantly attenuated after antibiotics eliminated intestinal microbiota (IM) of mice. In addition, FMP suppressed intestinal inflammation and oxidative stress levels by inhibiting the activation of the TLR4/MyD88/NF-κB pathway, and indirectly upregulated the expression of the tight junction proteins Claudin-1, Occludin, and Zonula occlusionn-1 (ZO-1) to repair the intestinal barrier. Interestingly, the protective effect of FMP on the intestinal barrier was also attributed to its regulation of IM. The 16S rRNA and Spearman correlation analysis showed that FMP could repair the intestinal barrier to improve T2DM by remodeling specific IM, especially by significantly inhibiting 93.66 % of endotoxin-producing Shigella and promoting the proliferation of probiotic Allobaculum and Bifidobacterium by 16.31 % and 19.07 %, respectively. This study provided a theoretical support for the application of FMP as a novel probiotic in functional foods for diabetes.

Salvia miltiorrhiza polysaccharide and its related metabolite 5-methoxyindole-3-carboxaldehyde ameliorate experimental colitis by regulating Nrf2/Keap1 signaling pathway

The roots of Salvia miltiorrhiza have been used in Traditional Chinese Medicine for thousands of years. However, tons of aerial parts of this plant are usually discarded in the production of roots preparation. To make better use of these plant resources, the polysaccharide isolated from the aerial part of S. miltiorrhiza was investigated for its potential protection against intestinal diseases. A pectic polysaccharide (SMAP-1) was isolated and characterized being composed of homogalacturonan as the main chain and rhamnogalacturonan type I as ramified region, with side chains including arabinans and possible arabinogalactan type I and II. SMAP-1 exhibited robust protective effects against dextran sodium sulfate (DSS)-induced colitis and restored colitis symptoms, colonic inflammation, and barrier functions. Anti-oxidative effects were also observed by up-regulating Nrf2/Keap1 signaling pathway. Additionally, the level of serum 5-methoxyindole-3-carboxaldehyde (5-MC) was restored by SMAP-1 identified in metabolomic analysis, being correlated with the aforementioned effects. Protection against oxidative stress on intestinal porcine enterocyte cells (IPEC-J2) by 5-MC was observed through the activation of Nrf2/Keap1 system, as also shown by SMAP-1. In conclusion, SMAP-1 could be a promising candidate for colitis prevention, and 5-MC could be the signal metabolite of SMAP-1 in protecting against oxidative stress in the intestine.