A neutral polysaccharide with a triple helix structure from ginger: Characterization and immunomodulatory activity

Ultrasonic-Assisted Extraction of Codonopsis pilosula Glucofructan: Optimization, Structure, and Immunoregulatory Activity

In recent years, multiple edible polysaccharides from Codonopsis pilosula were mainly isolated with high average molecular weights and exhibited various bioactivities, but it was proven that low-molecular-weight polysaccharides could exert stronger activities due to the superior water solubility and permeability. In the present study, the water-soluble polysaccharide C. pilosula with low molecular weight was isolated under ultrasonic assistance at 30 °C, the extraction process was optimized via response surface method (RSM), and the structure and immunoregulatory activity were further investigated. The maximum yield (4.86%) for crude polysaccharides (cCPPs) was obtained under following parameters: ultrasonic power of 370 W, liquid/material ratio of 33 mL/g, ultrasonic time of 81 min. Subsequently, the cCPPs were further purified through dialysis and Sephadex G-25 column to acquire purified polysaccharide (CPPs). Structural analysis indicated that CPPs was a glucofructan (average molecular weight of 4.23 × 10³ Da) with (2→1)-β-D-Fruf and (1→)-α-D-Glcp as the backbone branched by (2→6)-β-D-Fruf. Additionally, CPPs could enhance immunoregulatory function by stimulating NO production and cytokine (IL-6 and TNF-α) secretion of RAW264.7 macrophages dose-dependently, which presented no cytotoxic effects. These data suggest that CPPs have the potential to be used as a nutritional dietary compound and natural immunostimulant supplement in the food industry.

Characterization and immunomodulatory effect of an alkali-extracted galactomannan from Morchella esculenta

In our continuous exploration for bioactive polysaccharides, a novel polysaccharide FMP-2 was isolated and purified from the fruiting bodies of Morchella esculenta by alkali-assisted extraction. FMP-2 had an average molecular weight of 1.09 × 10⁶ Da and contained mannose, glucuronic acid, glucose, galactose, and arabinose in a molar ratio of 4.10:0.22:1.00:5.75:0.44. The backbone of FMP-2 mainly consisted of 1,2-α-D-Galp, 1,6-α-D-Galp, and 1,4-α-D-Manp, with branches of 1,4,6-α-D-Manp and 1,2,6-α-D-Galp. FMP-2 can stimulate phagocytosis and promote the secretion of NO, ROS, and cytokines like IL-6, IL-1β, and TNF-α in RAW264.7 cells ranging from 25 to 400 μg/mL. FMP-2 had great repairing effect on the immune injury of zebrafish induced by chloramphenicol. The phagocytosis ability of zebrafish macrophages and the proliferation of neutrophils can be greatly enhanced by polysaccharide FMP-2 with concentrations from 50 to 200 μg/mL. These findings suggest that FMP-2 might be used as a potential immunomodulator in the food and pharmaceutical industries.

Structure–immunomodulatory activity relationships of dietary polysaccharides

Polysaccharides are usually composed of more than ten monosaccharide units, which are connected by linear or branched glycosidic bonds. The immunomodulatory effect of natural polysaccharides is one of the most important bioactive function. In this review, molecular weight, monosaccharide (including galactose, mannose, rhamnogalacturonan-I arabinogalactan and uronic acid), functional groups (namely sulfate, selenium, and acetyl groups), types of glycoside bond connection (including β-1,3-D-glucosyl, α-1,4-D-glucosyl, β-1,4-D-glucosyl, α-1,6-D-glucosyl, β-1,4-D-mannosyl, and β-1,4-D-Xylopyranosyl), conformation and the branching degrees are systematically identified as their contribution to the immunostimulatory activity of polysaccharides. At present, studies on the structure-activity relationships of polysaccharides are limited due to their low purity and high heterogeneity. However, it is an important step in providing useful guidance for dietary supplements with polysaccharides. The chemical structures and the process of immune responses induced are necessary to be discussed. Polysaccharides may bind with the cell surface receptors to modulate immune responses. This review mainly discusses the structure-activity relationship of dietary polysaccharides.

•

Structure - activity relationships of polysaccharides with immune-enhancing effect are proposed.

•

Polysaccharides with the higher molecular weight are helpful to improve immunity.

•

Higer galactose, mannose, rhamnogalacturonan-I, arabinogalacta,n and uronic acid contents have immunoregulation.

Chemical elucidation of an arabinogalactan from rhizome of Polygonatum sibiricum with antioxidant activities

Polygonatum sibiricum is traditionally used as Chinese medicine for immunity enhancement. Exploration of polysaccharides from Polygonatum species would provide a wider insight into the studies on their chemical structures and function activities. In this study, the alkali-extracted polysaccharide from P. sibiricum (PSP) was isolated and examined. The polysaccharide was firstly isolated by ion-exchange chromatography equipped with DE52 column, followed by isolated through Superdex-200 column. The obtained PSPJWA fraction was a homogenous one with average molecular weight of 141 kDa. The monosaccharide composition was galactose, arabinose and rhamnose in a ratio of 14:4:1. The glycosidic linkages of PSPJWA fraction were indicated to be Araf-(1→, →5)-Araf-(1→, →3,5)-Araf-(1→, Galp-(1→, →4)-Galp-(1→, →4,6)-Galp-(1→ and →2,4)-Rhap-(1→ residue by methylation analysis. NMR and enzymatic studies showed that PSPJWA was a novel arabinogalactan-type structure. PSPJW polysaccharides with different molecular weight and similar chemical structure had different antioxidant activities. Together, P. sibiricum polysaccharide has the potential to be a natural antioxidant.

Optimization of the composite enzyme extraction of polysaccharide from Erythronium sibiricum bulb and its immunoregulatory activities

An efficient compound enzyme extraction process was developed and optimized to extract the polysaccharide from Erythronium sibiricum bulb via response surface methodology. The polysaccharide E2P was obtained. Then, the preliminary characteristics of E2P were determined via colorimetry and chromatography. Additionally, the immunoregulatory activities of E2P and another polysaccharide (ESBP, extracted using the hot water method) were compared. The optimized extraction results were as follows: temperature (54.56 °C), time (2.52 h), pH (6.53), and enzyme concentration ratio (0.5% cellulase:1.5% amylase). The yield (64.18% ± 2.91%) obtained under the aforementioned conditions was considerably higher than the yield of ESBP (37.25% ± 0.17%). The total sugar, uronic acid, starch, and protein contents of E2P were 81.77% ± 2.84%, 3.31% ± 0.45%, 3.29% ± 0.01%, and 0.24% ± 0.02%, respectively. The HPLC result suggested that the predominant monosaccharides of E2P included glucose, galactose, and arabinose, with a molar ratio of 543.2:1:1.8. The in vitro tests in RAW264.7 cells indicated that ESBP exhibited better immunomodulatory activities than E2P. In particular, ESBP can promote the proliferation, phagocytosis, and cytokine secretion abilities of cytokines, such as nitric oxide, tumor necrosis factor-α, and interleukin (IL)-1β of RAW264.6 cells. By contrast, E2P can only promote phagocytosis ability and the secretion of IL-1β.

Molecular mechanisms underlying macrophage immunomodulatory activity of Rubus chingii Hu polysaccharides

The present study was to investigate the mechanisms involved in macrophage activation by polysaccharides from the fruits of Rubus chingii Hu (RFPs). The results showed that RFPs enhanced pinocytic and phagocytic activity, promoted the expression and secretion of inflammatory factors (ROS, PTGS2, iNOS, IL-6, IL-10 and TNF-α) and chemokines (CCL2 and CXCL10), and boosted the expression of accessory and costimulatory molecules (CD40, CD80, CD86, MHC-I and MHC-II). RNA-Seq analysis identified 2564 DEGs, 1710 GO terms and 101 KEGG pathways. TNF was identified as the core gene via analysis of pathway information integration and PPI network. The western blot analysis combined with functional verification assay confirmed that MAPK, NF-κB and Jak-STAT pathways were essential to RFPs-mediated macrophage activation. TLR2 was revealed to be the functional receptor and involved in the early recognition of RFPs. These results indicated that RFPs modulated macrophage immune response mainly through TLR2-dependent MAPK, NF-κB and Jak-STAT pathways.

Structural elucidation and immunomodulatory evaluation of a polysaccharide from Stevia rebaudiana leaves

Stevia rebaudiana, a sweetener with medicinal functions, has attracted extensive attention due to its application in food and pharmaceutical fields. However, a few studies were performed to explore polysaccharides in this plant. Herein, SRP70-1 was derived from S. rebaudiana. Structural analysis (monosaccharide composition analysis, high-performance liquid chromatography-multi-angle light scattering detection, gas chromatography-mass spectrometry, and nuclear magnetic resonance spectroscopy) revealed that SRP70-1 was composed of mannose, glucose, galactose, and arabinose at the molar ratio of 1.35:1.00:3.23:3.47, with an absolute molecular weight of 7698 Da. SRP70-1 was found to contain → 5)-α-l-Araf-(1→, →2,3,5)-α-l-Araf-(1→, →4)-β-l-Arap-(1→, →4)-β-d-Galp-(1→, →6)-β-d-Galp-(1→, →4)-β-d-Manp-(1→, →6)-β-d-Manp-(1→, and terminal α-l-Araf, β-d-Galp, and β-d-Glcp residues. Cell experiments showed that SRP70-1 could significantly promote phagocytosis and increase the release of nitric oxide and cytokines including IL-1β, IL-6, and TNF-α. Further zebrafish experiments confirmed the immunological enhancement effects of SRP70-1. This study revealed that SRP70-1 may be useful for the development of functional foods.

Recent Developments in Inonotus obliquus (Chaga mushroom) Polysaccharides: Isolation, Structural Characteristics, Biological Activities and Application

Inonotus obliquus (Chaga mushroom) is a kind of medicine and health food widely used by folk in China, Russia, Korea, and some occidental countries. Among the extracts from Inonotus obliquus, Inonotus obliquus polysaccharide (IOPS) is supposed to be one of the major bioactive components in Inonotus obliquus, which possesses antitumor, antioxidant, anti-virus, hypoglycemic, and hypolipidemic activities. In this review, the current advancements on extraction, purification, structural characteristics, and biological activities of IOPS were summarized. This review can provide significant insight into the IOPS bioactivities as their in vitro and in vivo data were summarized, and some possible mechanisms were listed. Furthermore, applications of IOPS were reviewed and discussed; IOPS might be a potential candidate for the treatment of cancers and type 2 diabetes. Besides, new perspectives for the future work of IOPS were also proposed.