The great potential of polysaccharides in immunological regulation has recently been highlighted in pharmacological and clinical studies. Polysaccharides can trigger immunostimulatory responses through molecular identification, intra- and intercellular communication via direct or indirect interactions with the immune system. Various immunostimulatory polysaccharides or their derivative compounds interacts at cellular level to boost the immune system, including arabinogalactans, fucoidans, mannans, xylans, galactans, hyaluronans, fructans, pectin and arabinogalactans, etc. These natural polysaccharides are derived from various plants, animals and microbes. A unique structural diversity has been identified in polysaccharides, while monosaccharides and glucosidic bonds mainly confer diverse biological activities. These natural polysaccharides improve antioxidant capacity, reduce the production of pro-inflammatory mediators, strengthen the intestinal barrier, influence the composition of intestinal microbial populations and promote the synthesis of short-chain fatty acids. These natural polysaccharides are also known to reduce excessive inflammatory responses. It is crucial to develop polysaccharide-based immunomodulators that could be used to prevent or treat certain diseases. This review highlights the structural features, immunomodulatory properties, underlying immunomodulatory mechanisms of naturally occurring polysaccharides, and activities related to immune effects by elucidating a complex relationship between polysaccharides and immunity. In addition, the future of these molecules as potential immunomodulatory components that could transform pharmaceutical applications at clinical level will also be highlighted.

Background: At present, the incidence of alcoholic fatty liver disease (AFLD) is increasing year by year, and numerous studies have confirmed that liver diseases are closely related to intestinal flora. Seabuckthorn and Astragalus membranaceus, as traditional Chinese medicine (TCM) with the homology of medicine and food, have good liver protection, and their polysaccharides can regulate the intestinal flora. Here, we studied the effects of HRP, APS and the combination of the two polysaccharides on the intestinal flora of AFLD mice, which provided scientific basis for the treatment of AFLD with the two polysaccharides.Materials and methods: Thirty Kunming (KM) mice were randomly divided into the control group (Con), the model group (Mod), the HRP treatment group (HRP), the APS treatment group (APS), and HRP+APS treatment group (HRP+APS), with six mice in each group. The AFLD model was constructed by continuous intragastric administration of 42% vol Niulanshan ethanol solution for 28 days, and the mice in each polysaccharide group were given corresponding drugs. The levels of AST, ALT, TC and TG in serum of mice were measured. 16S rRNA amplicon sequencing technique was used to determine the diversity and richness of intestinal flora, and the relative abundance of intestinal flora at phylum level and genus level of the mice in each group.Results: HRP, APS and HRP+APS could reduce the serum levels of AST, ALT, TC and TG in mice. In addition, HRP, APS and HRP + APS restored the diversity, relative abundance and community structure of intestinal mucosa bacteria in AFLD mice to a certain extent. Specifically, HRP, APS and HRP+APS remarkably decreased the ratio of Firmicutes to Bacteroidetes, and ultimately increased the abundance of beneficial bacteria and reduced the abundance of pathogenic bacteria.Conclusion: HRP, APS, and HRP+APS can improve the intestinal microecology of AFLD model mice, alleviate liver injury, and maintain normal intestinal function in different degrees.

Polysaccharides have been assessed as a potential natural active component in Chinese herbal medicine with anti-inflammatory properties. However, the complex and indefinite structures of polysaccharides limit their applications. This study explains the structures and anti-inflammatory potentials of three neutral polysaccharides, RIP-A1 (M_w 1.8 × 10⁴ Da), RIP-B1 (M_w 7.4 × 10⁴ Da) and RIP-B2 (M_w 9.3 × 10⁴ Da), which were isolated from the roots of Isatis indigotica Fort. with sequenced ultrafiltration membrane columns, DEAE-52 and Sephadex G-100. The planar structures and microstructures of RIP-A1, RIP-B1 and RIP-B2 were further determined by HPGPC, GC–MS, methylation analysis, FT-IR, SEM and AFM, in which the structure of RIP-A1 was elucidated in detail using 1D/2D NMR. The Raw 264.7 cells were used for the anti-inflammatory activity in vitro. The results showed that RIP-A1, RIP-B1 and RIP-B2 are all neutral polysaccharides, with RIP-A1 having the smallest M_w and the simplest monosaccharide composition of the three. RIP-A1 is mainly composed of Ara and Gal, except for a small quantity of Rha. Its main structure is covered with glycosidic linkages of T-α-Araf, 1,2-α-Rhap, 1,5-α-Araf, T-β-Galp, 1,2,4-α-Rhap, 1,3,5-α-Araf and 1,6-β-Galp with 0.33:0.12:1.02:0.09:0.45:11.41:10.23. RIP-A1 significantly inhibited pro-inflammatory cytokines (NO, TNF-α, IL-6 and IL-1β) and increased anti-inflammatory cytokines (IL-4) in LPS-stimulated RAW 264.7 cells. Moreover, RIP-A1 could significantly inhibit the mRNA expression of TNF-α, IL-6 and L-1β. It could also activate IKK, p65 and IκBα (the components of the NF-κB signaling pathway). In conclusion, the above results show the structural characterization and anti-inflammatory potentials of RIP-A1 as an effective natural anti-inflammatory drug.

Obesity, a chronic metabolic disease with a complex pathophysiology, is caused by several variables. High-fat diets lead to the disruption of the gut microbiota and impaired gut barrier function in obese people. The dysbiosis and its metabolites through the intestinal barrier lead to an imbalance in energy metabolism and inflammatory response, which eventually contributes to the development of chronic diseases such as diabetes, hypertension, and cardiovascular disease. Current medicines are therapeutic to obesity in the short term; however, they may bring significant physical and emotional problems to patients as major side effects. Therefore, it is urgent to explore new therapeutic methods that have definite efficacy, can be taken for a long time, and have mild adverse effects. Numerous studies have demonstrated that traditional Chinese medicine (TCM) can control the gut microbiota in a multi-targeted and comprehensive manner, thereby restoring flora homeostasis, repairing damaged intestinal mucosal barriers, and eventually curbing the development of obesity. The active ingredients and compounds of TCM can restore the normal physiological function of the intestinal mucosal barrier by regulating gut microbiota to regulate energy metabolism, inhibit fat accumulation, affect food appetite, and reduce intestinal mucosal inflammatory response, thereby effectively promoting weight loss and providing new strategies for obesity prevention and treatment. Although there are some studies on the regulation of gut microbiota by TCM to prevent and treat obesity, all of them have the disadvantage of being systematic and comprehensive. Therefore, this work comprehensively describes the molecular mechanism of obesity mediated by gut microbiota based on the research state of obesity, gut microbiota, and TCM. A comprehensive and systematic summary of TCM targeting the regulation of gut microbiota for the treatment of obesity should be conducted in order to provide new strategies and ideas for the treatment of obesity.

Background: A microneedle patch loaded with Atractylodes macrocephala Rhizoma water extract was prepared for the treatment of mammary gland hyperplasia. To explore the relationship between Mammary gland hyperplasia and intestinal flora.Materials and methods: Preparation of the microneedle patch by micromolding method, the prescription of the microneedle was optimized by the Box-Behnken Design response surface test, and the micro-morphology, penetration, toughness, and brittleness were investigated. In vitro release of drug-loaded microneedles was measured by diffusion cell method. The rat model of mammary gland hyperplasia was prepared by the combination of estradiol benzoate-progesterone, and the microneedle patch of Atractylodes macrocephala Rhizoma aqueous extract was used for intervention treatment. The change of levels in E₂, P, and PRL in rat serum was determined. The intestinal contents of rats were collected and the changes in intestinal flora in MGH rats were analyzed by 16s rRNA high-throughput sequencing.Results: The optimized microneedle formula is a PVA concentration of 6.0%, HA concentration of 15.5%, and PVPK30 concentration of 16.0%. The prepared microneedle tip loaded with Atractylodes macrocephala Rhizoma aqueous extract has complete, sharp, and no bubbles and the needle rate of the microneedle array is in the range of 95%~100%. The bending rate of the microneedle is about 12.7%, and it has good flexibility, and the microneedle can puncture 4 layers of ParafilmⓇ membrane smoothly, and the puncture rate is more than 96%. The in vitro release of the microneedle was characterized by rapid release. The results of animal experiments showed that Atractylodes macrocephala Rhizoma aqueous extract microneedle patch could significantly reduce the E₂ level, significantly reduce the PRL level, and significantly increase the P level. At the same time, it can regulate the abundance and diversity of intestinal flora in MGH rats, improve the intestinal flora disorder caused by mammary gland hyperplasia, and balance the community structure.Conclusion: The prepared microneedle containing Atractylodes macrocephala Rhizoma aqueous extract has good toughness and brittle strength, can penetrate the skin and enter the dermis, and effectively deliver drugs to play a role in the treatment of mammary gland hyperplasia.