Anti-tumor activity and immunogenicity of a succinoglycan riclin

Enhanced physicochemical, rheological and antioxidant properties of highly succinylated succinoglycan exopolysaccharides obtained through succinic anhydride esterification reaction

Highly succinylated succinoglycan (HS-SG) was prepared by reacting succinic anhydride with succinoglycan (SG) exopolysaccharide isolated from Sinorhizobium meliloti. The rheological, physicochemical properties, and antioxidant effects of HS-SG were evaluated in comparison with SG. NMR and FTIR analyses confirmed that HS-SG retained the characteristic glycosidic structure of SG while showing a relative increase in succinyl functional groups. DSC analysis revealed that HS-SG 50, with a reaction molar ratio of SG to succinic anhydride of 1:50, exhibited a higher endothermic peak at 151 °C, indicating improved thermal stability compared to SG's peak at 93 °C. Rheological analysis demonstrated that HS-SG 50 had a viscosity 250 % higher than SG at a shear rate of 10 s-1. Unlike SG, whose viscosity dropped to less than 1 % above 60 °C, HS-SG 50 maintained about 30 % viscosity at the same temperature. Additionally, HS-SG 50 showed significantly enhanced antioxidant activity in DPPH and hydroxyl radical scavenging tests and was non-toxic in a cytotoxicity test using HEK-293 cells. These findings suggest that highly succinylated succinoglycan exhibits improved thermal stability, viscosity, and antioxidant properties, making it a promising biomaterial for applications in cosmetics, pharmaceuticals, biomedicine, and polysaccharide-based biotechnology.

Characterization of gelatin-oxidized riclin cryogels and their applications as reusable ice cubes in shrimp preservation

Traditional ice is usually employed to preserve food freshness and extend shelf life. However, ice cannot bear repeated freeze - thaw cycles during the transportation and retailing process, resulting in microbial cross-contamination and spoilage of foods. Herein, succinoglycan riclin was oxidated (RO) and crosslinked with gelatin (Ge), the Ge-RO cryogels were prepared via Schiff base reaction and three freeze - thaw cycles. The Ge-RO cryogels showed improved storage modulus (G') and thermal stability compared with pure gelatin hydrogel. The polymer framework of Ge-RO gels exhibited stable properties against ice crystals destructions during nine freeze - thaw treatments. During the storage and repeated freeze - thaw treatments of shrimps, Ge-RO cryogels exhibited a remarkable preservation effect on shrimps, and their freshness was evaluated using an electronic nose technique equipped with ten sensors. The results demonstrated that the shrimp muscle preserved in ice generated off-odors and resulted in high sensor responses. The sensor responses were reduced sharply of shrimps preserved in cryogels. Moreover, 1H NMR-based metabolomics analysis revealed that shrimps in Ge-RO cryogels group reversed the metabolic perturbations compared with the traditional ice group, the metabolic pathways were related to energy metabolism, nucleotide metabolism, and amino acid metabolism, which provide new clues to the freshness of shrimps. Furthermore, RO exhibited superior antimicrobial activity against E. coli and S. aureus microorganisms. Thus, the crosslinked cryogels are potentially applicable to food preservation, offering sustainable and reusable solutions against traditional ice.

An exopolysaccharide pathway from a freshwater Sphingomonas isolate

Bacteria embellish their cell envelopes with a variety of specialized polysaccharides. Biosynthesis pathways for these glycans are complex, and final products vary greatly in their chemical structures, physical properties, and biological activities. This tremendous diversity comes from the ability to arrange complex pools of monosaccharide building blocks into polymers with many possible linkage configurations. Due to the complex chemistry of bacterial glycans, very few biosynthetic pathways have been defined in detail. As part of an initiative to characterize novel polysaccharide biosynthesis enzymes, we isolated a bacterium from Lake Michigan called Sphingomonas sp. LM7 that is proficient in exopolysaccharide (EPS) production. We identified genes that contribute to EPS biosynthesis in LM7 by screening a transposon mutant library for colonies displaying altered colony morphology. A gene cluster was identified that appears to encode a complete wzy/wzx-dependent polysaccharide assembly pathway. Deleting individual genes in this cluster caused a non-mucoid phenotype and a corresponding loss of EPS secretion, confirming the role of this gene cluster in polysaccharide production. We extracted EPS from LM7 cultures and determined that it contains a linear chain of 3- and 4-linked glucose, galactose, and glucuronic acid residues. Finally, we show that the EPS pathway in Sphingomonas sp. LM7 diverges from that of sphingan-family EPSs and adhesive polysaccharides such as the holdfast that are present in other Alphaproteobacteria. Our approach of characterizing complete biosynthetic pathways holds promise for engineering polysaccharides with valuable properties.

IMPORTANCE

Bacteria produce complex polysaccharides that serve a range of biological functions. These polymers often have properties that make them attractive for industrial applications, but they remain woefully underutilized. In this work, we studied a novel polysaccharide called promonan that is produced by Sphingomonas sp. LM7, a bacterium we isolated from Lake Michigan. We extracted promonan from LM7 cultures and identified which sugars are present in the polymer. We also identified the genes responsible for polysaccharide production. Comparing the promonan genes to those of other bacteria showed that promonan is distinct from previously characterized polysaccharides. We conclude by discussing how the promonan pathway could be used to produce new polysaccharides through genetic engineering.

Targeting senescent cells to reshape the tumor microenvironment and improve anticancer efficacy

Cancer is daunting pathology with remarkable breadth and scope, spanning genetics, epigenetics, proteomics, metalobomics and cell biology. Cellular senescence represents a stress-induced and essentially irreversible cell fate associated with aging and various age-related diseases, including malignancies. Senescent cells are characterized of morphologic alterations and metabolic reprogramming, and develop a highly active secretome termed as the senescence-associated secretory phenotype (SASP). Since the first discovery, senescence has been understood as an important barrier to tumor progression, as its induction in pre-neoplastic cells limits carcinogenesis. Paradoxically, senescent cells arising in the tumor microenvironment (TME) contribute to tumor progression, including augmented therapeutic resistance. In this article, we define typical forms of senescent cells commonly observed within the TME and how senescent cells functionally remodel their surrounding niche, affect immune responses and promote cancer evolution. Furthermore, we highlight the recently emerging pipelines of senotherapies particularly senolytics, which can selectively deplete senescent cells from affected organs in vivo and impede tumor progression by restoring therapeutic responses and securing anticancer efficacies. Together, co-targeting cancer cells and their normal but senescent counterparts in the TME holds the potential to achieve increased therapeutic benefits and restrained disease relapse in future clinical oncology.

Hydrogel Based on Riclin Cross-Linked with Polyethylene Glycol Diglycidyl Ether as a Soft Filler for Tissue Engineering

Hydrogels composed of natural polysaccharides have been widely used as filling materials, with a growing interest in medical cosmetology and skin care. However, conventional commercial dermal fillers still have limitations, particularly in terms of mechanical performance and durability in vivo. In this study, a novel injectable and implantable hydrogel with adjustable characteristics was prepared from succinoglycan riclin by introducing PEG diglycidyl ether as a cross-linker. FTIR spectra confirmed the cross-linking reaction. The riclin hydrogels exhibited shear-thinning behavior, excellent mechanical properties, and cytocompatibility through in vitro experiments. Furthermore, when compared with subcutaneous injection of a commercial hyaluronic acid hydrogel, the riclin hydrogels showed enhanced persistence and biocompatibility in Balb/c mice after 16 weeks. These results demonstrate the great potential of the riclin-based hydrogel as an alternative to conventional commercial soft tissue fillers.

Physicochemical and Rheological Properties of Succinoglycan Overproduced by Sinorhizobium meliloti 1021 Mutant

Commercial bacterial exopolysaccharide (EPS) applications have been gaining interest; therefore, strains that provide higher yields are required for industrial-scale processes. Succinoglycan (SG) is a type of bacterial anionic exopolysaccharide produced by Rhizobium, Agrobacterium, and other soil bacterial species. SG has been widely used as a pharmaceutical, cosmetic, and food additive based on its properties as a thickener, texture enhancer, emulsifier, stabilizer, and gelling agent. An SG-overproducing mutant strain (SMC1) was developed from Sinorhizobium meliloti 1021 through N-methyl-N'-nitro-N-nitrosoguanidine (NTG) mutation, and the physicochemical and rheological properties of SMC1-SG were analyzed. SMC1 produced (22.3 g/L) 3.65-fold more SG than did the wild type. Succinoglycan (SMC1-SG) overproduced by SMC1 was structurally characterized by FT-IR and 1H NMR spectroscopy. The molecular weights of SG and SMC1-SG were 4.20 × 105 and 4.80 × 105 Da, respectively, as determined by GPC. Based on DSC and TGA, SMC1-SG exhibited a higher endothermic peak (90.9 °C) than that of SG (77.2 °C). Storage modulus (G') and loss modulus (G″) measurements during heating and cooling showed that SMC1-SG had improved thermal behavior compared to that of SG, with intersections at 74.9 °C and 72.0 °C, respectively. The SMC1-SG's viscosity reduction pattern was maintained even at high temperatures (65 °C). Gelation by metal cations was observed in Fe3+ and Cr3+ solutions for both SG and SMC1-SG. Antibacterial activities of SG and SMC1-SG against Escherichia coli and Staphylococcus aureus were also observed. Therefore, like SG, SMC1-SG may be a potential biomaterial for pharmaceutical, cosmetic, and food industries.

A novel exopolysaccharide pathway from a freshwater Sphingomonas isolate

Bacteria embellish their cell envelopes with a variety of specialized polysaccharides. Biosynthesis pathways for these glycans are complex, and final products vary greatly in their chemical structures, physical properties and biological activities. This tremendous diversity comes from the ability to arrange complex pools of monosaccharide building blocks into polymers with many possible linkage configurations. Due to the complex chemistry of bacterial glycans, very few biosynthetic pathways have been defined in detail. To better understand the breadth of polysaccharide production in nature we isolated a bacterium from Lake Michigan called Sphingomonas sp. LM7 that is proficient in exopolysaccharide (EPS) production. We identified genes that contribute to EPS biosynthesis in LM7 by screening a transposon mutant library for colonies displaying altered colony morphology. A gene cluster was identified that appears to encode a complete wzy/wzx-dependent polysaccharide assembly pathway. Deleting individual genes in this cluster caused a non-mucoid phenotype and a corresponding loss of EPS secretion, confirming that LM7 assembles a novel wzy/wzx-dependent polysaccharide. We extracted EPS from LM7 cultures and showed that it contains a linear chain of 3- and 4- linked glucose, galactose, and glucuronic acid residues. Finally, we found that the EPS pathway we identified diverges from those of adhesive polysaccharides such as the holdfast that are conserved in higher Alphaproteobacteria. Our approach of characterizing complete biosynthetic pathways holds promise for engineering of polysaccharides with valuable properties.

Polysaccharide‑platinum complexes for cancer theranostics

Platinum anticancer drugs have been explored and developed in recent years to reduce systematic toxicities and resist drug resistance. Polysaccharides derived from nature have abundant structures as well as pharmacological activities. The review provides insights on the design, synthesis, characterization and associating therapeutic application of platinum complexes with polysaccharides that are classified by electronic charge. The complexes give birth to multifunctional properties with enhanced drug accumulation, improved tumor selectivity and achieved synergistic antitumor effect in cancer therapy. Several techniques developing polysaccharides-based carriers newly are also discussed. Moreover, the lasted immunoregulatory activities of innate immune reactions triggered by polysaccharides are summarized. Finally, we discuss the current shortcomings and outline potential strategies for improving platinum-based personalized cancer treatment. Using platinum-polysaccharides complexes for improving the immunotherapy efficiency represents a promising framework in future.

Exopolysaccharide riclin and anthocyanin-based composite colorimetric indicator film for food freshness monitoring

Food freshness monitoring is vital to ensure food safety. Recently, packaging materials incorporating pH-sensitive films have been employed to monitor the freshness of food products in real time. The film-forming matrix of the pH-sensitive film is essential to maintain the desired physicochemical functions of the packaging. Conventional film-forming matrices, such as polyvinyl alcohol (PVA), have drawbacks of low water resistance, poor mechanical properties, and weak antioxidant ability. In this study, we successfully synthesise PVA/riclin (P/R) biodegradable polymer films to overcome these limitations. The films feature riclin, an agrobacterium-derived exopolysaccharide. The uniformly dispersed riclin conferred outstanding antioxidant activity to the PVA film and significantly improved its tensile strength and barrier properties by forming hydrogen bonds. Purple sweet potato anthocyanin (PSPA) was used as a pH indicator. The intelligent film with added PSPA provided robust surveillance of volatile ammonia and changed its color within 30 s in the pH range of 2-12. This multifunctional colorimetric film also engendered discernible color changes when the quality of shrimp deteriorated, demonstrating its great potential as an intelligent packaging material to monitor food freshness.

New Polyvinyl Alcohol/Succinoglycan-Based Hydrogels for pH-Responsive Drug Delivery

We fabricated new hydrogels using polyvinyl alcohol (PVA) and succinoglycan (SG) directly isolated and obtained from Sinorhizobium meliloti Rm 1021 via the freeze-thaw method. Both the composition of the hydrogels and the freeze-thaw cycles were optimized to maximize the swelling ratio for the preparation of the PVA/SG hydrogels. During the optimization process, the morphology and conformational change in the hydrogel were analyzed by scanning electron microscopy, rheological measurements, and compressive tests. An optimized hydrogel with a maximum swelling ratio of 17.28 g/g was obtained when the composition of PVA to SG was 50:50 (PVA/SG 50/50) and the total number of freeze-thaw cycles was five. The PVA/SG 50/50 hydrogel had the largest pore with 51.24% porosity and the highest cross-over point (28.17%) between the storage modulus (G') and the loss modulus (G″). The PVA/SG 50/50 hydrogel showed improved thermal stability owing to its interaction with thermally stable SG chains. The improvement in the thermal stability was confirmed by thermogravimetric analysis and differential scanning calorimetry. In addition, the PVA/SG 50/50 hydrogel showed differential drug release according to the corresponding pH under acidic conditions of pH 1.2 and slightly basic conditions of pH 7.4. Furthermore, the cell viability test on the HEK-293 cell line for that hydrogel demonstrated that the PVA/SG 50/50 hydrogel was non-toxic and biocompatible. Therefore, this hydrogel could be a potential scaffold capable of pH-responsive drug delivery for chronic wound dressing applications.

Succinoglycan riclin relieves UVB-induced skin injury with anti-oxidant and anti-inflammatory properties

Excessive UVB exposure increases the production of reactive oxygen species (ROS), which causes oxidative damage and epidermal inflammation. Previous studies have identified that the succinoglycan riclin has potent anti-inflammatory properties. The current study aims to investigate whether riclin protects against UVB-induced photodamage. In vitro, riclin demonstrated excellent moisture-preserving properties, along with antioxidant potential by scavenging superoxide anions, hydroxyl and DPPH radicals. Riclin increased Col1α1 and Col3α1 expression in NIH3T3 cells, inhibited oxidation and melanin synthesis by B16F10 cells upon UVB irradiation. In vivo, topical application of riclin effectively attenuated UVB-induced skin damage in C57BL6 mice, which was characterized by erythema, epidermal hyperplasia, hydroxyproline loss and ROS production in skin tissue. Riclin suppressed skin inflammation by the elevation of TNF-α, IL-6, IL-β, and alleviated UVB-induced immune cell up-regulation. Moreover, treatment with a Dectin-1 inhibitor reversed the protective effect of riclin in THP-1 cells.

Antitumor Potential and Structure Characterization of Polysaccharides From Lagotis brevituba Maxim in the Tibetan Plateau

This study purified two polysaccharides (LBMPs) from Lagotis brevituba Maxim in several steps. The chemical structure of LBMP-2 was determined by HPGPC, FT-IR, IC, ¹H and ¹³C NMR, AFM, SEM, and TEM. The results show that LBMP-2 was mainly composed of GalA, and the Mw of LBMP-2 is 23.799 kDa. In addition, the antioxidant activity, and the antitumor activity in vitro and in vivo were studied. LBMP-2 has excellent antioxidant and antitumor capacity. The inhibition of tumor cell proliferation in vitro may result in the inhibition of aerobic respiration and glycolysis. Tumor growth inhibition in vivo may inhibit the expression of AMPK in tumors and enhance spleen function. Compared with conventional chemotherapy drug cyclophosphamide, LBMP-2 is less harmful to the body and safer. Therefore, LBMP-2 provides a potential source of antitumor drugs.

Riclin-Capped Silver Nanoparticles as an Antibacterial and Anti-Inflammatory Wound Dressing

Purpose

In order to overcome the inflammatory response to bacterial infection during wound healing, we have fabricated an antibacterial and anti-inflammatory wound dressing based on polysaccharide riclin and silver nanoparticles (AgNPs).

Methods

The riclin-AgNPs nanocomposite was developed by borohydride method and was characterized by UV-Vis, TEM, XRD, Zeta potential, DLS. In vitro, we assessed the cumulative release, antibacterial activities and cytotoxicity. In vivo, we examined the wound healing in mice wound infection experiment and inflammatory mediators using histological observations and gene expression analysis.

Results

The riclin/AgNPs nanocomposite hydrogel exhibited nanosized orbicular particles with high purity and stability. In vitro, the riclin/AgNPs showed sustained release of AgNPs, effective suppression in pathogen growth and negligible toxicity toward mammalian fibroblasts and macrophage cells. In vivo, the riclin/AgNPs treatment leads to faster and smoother growth of fresh skin with suppressed expression of inflammatory mediators.

Conclusion

The reported Riclin-AgNPs nanocomposite hydrogel showed both antibacterial and anti-inflammatory functions, which induce significantly accelerated wound healing, indicating great potential as a novel attractive wound dressing material.

Dietary Succinoglycan Riclin Improves Glycemia Control in Mice with Type 2 Diabetes

Riclin is a typical succinoglycan produced by an agrobacterium isolate. Our previous investigation has revealed that oral riclin restores the islet function in type 1 diabetic mice. However, whether dietary riclin improves glycemic control in type 2 diabetes (T2D) is unknown. Here, we found that dietary riclin (20 and 40 mg/kg) for 4 weeks significantly decreased fasting blood glucose (55 and 67%), improved insulin sensitivity, and decreased insulin resistance in high-fat-diet/streptozocin (HFD/STZ)-induced T2D. Riclin reduced the proportion of T helper 1 cell subsets in diabetic mice, alleviated pancreatic inflammation, and protected islet function. Moreover, dietary riclin enriched the diversity of gut microflora and restored the relative abundance of several bacterial genera in diabetes, including the strains of Clostridium, Parasutterella, Klebsiella, and Bacteroides. In db/db diabetic mice, riclin also improves glycemia control as observed in HFD/STZ-induced T2D mice. These data suggest that riclin has potential to be a functional food to treat T2D.

Bacterial Succinoglycans: Structure, Physical Properties, and Applications

Succinoglycan is a type of bacterial anionic exopolysaccharide produced from Rhizobium, Agrobacterium, and other soil bacteria. The exact structure of succinoglycan depends in part on the type of bacterial strain, and the final production yield also depends on the medium composition, culture conditions, and genotype of each strain. Various bacterial polysaccharides, such as cellulose, xanthan, gellan, and pullulan, that can be mass-produced for biotechnology are being actively studied. However, in the case of succinoglycan, a bacterial polysaccharide, relatively few reports on production strains or chemical and structural characteristics have been published. Physical properties of succinoglycan, a non-Newtonian and shear thinning fluid, have been reported according to the ratio of substituents (pyruvyl, succinyl, acetyl group), molecular weight (M_w), and measurement conditions (concentration, temperature, pH, metal ion, etc.). Due to its unique rheological properties, succinoglycan has been mainly used as a thickener and emulsifier in the cosmetic and food industries. However, in recent reports, succinoglycan and its derivatives have been used as functional biomaterials, e.g., in stimuli-responsive drug delivery systems, therapeutics, and cell culture scaffolds. This suggests a new and expanded application of succinoglycan as promising biomaterials in biomedical fields, such as tissue engineering, regenerative medicine, and pharmaceuticals using drug delivery.

The succinoglycan riclin restores beta cell function through the regulation of macrophages on Th1 and Th2 differentiation in type 1 diabetic mice

Bacterial succinoglycan is found suitable as a viscosifying and emulsifying agent in the food industry. Riclin is a de-succinyl succinoglycan from an Agrobacterium isolate. Our previous study has revealed that riclin exerts special anti-inflammatory effects in vitro and in vivo. This study aims to determine the effects of riclin on preventing against immunological injury of beta cells in a type 1 diabetic model. We found that orally riclin effectively restores beta-cell function and improves the complications of streptozotocin (STZ)-induced diabetes. Riclin also reduces STZ-induced liver and kidney damage, and balances the inappropriate ratio of T helper type 1 cell (Th1)/type 2 cell (Th2) in the spleen and pancreatic draining lymph nodes of the STZ-induced diabetic mice. In a co-culture system with the islet β cell MIN6 and macrophage RAW 264.7, riclin reduces the levels of IFN-γ and IL-1β, protecting against STZ-caused MIN6 cell injury. We identified that riclin specifically binds to the membrane of macrophages and regulates the ratio of IL-10 and IL-12, thereby inhibiting the macrophage-mediated polarization of Th1 cells and promoting the differentiation of Th2 cells, which depends on the dendritic cell-specific intercellular adhesion molecule-3-grabbing non-integrin (DC-SIGN) receptor. Moreover, orally riclin significantly decreases the incidence of STZ-induced hyperglycemia (7.1% in riclin vs. 92.9% in STZ), and prevents autoimmune diabetes in non-obese diabetic (NOD) mice, with 87.5% of mice free of diabetes compared to 46.6% of the control mice. These results suggest that riclin has potential to be a functional food to prevent and improve autoimmune diabetes and related diseases.

Riclinoctaose Attenuates Renal Ischemia-Reperfusion Injury by the Regulation of Macrophage Polarization

Renal ischemia-reperfusion injury is a major trigger of acute kidney injury and leads to permanent renal impairment, and effective therapies remain unresolved. Riclinoctaose is an immunomodulatory octasaccharide composed of glucose and galactose monomers. Here we investigated whether riclinoctaose protects against renal ischemia-reperfusion injury. In mice, pretreatment with riclinoctaose significantly improved renal function, structure, and the inflammatory response after renal ischemia-reperfusion. Flow cytometry analysis revealed that riclinoctaose inhibited ischemia-reperfusion-induced M1 macrophage polarization and facilitated M2 macrophage recruitment into the kidneys. In isolated mouse bone marrow-derived macrophages, pretreatment with riclinoctaose promoted the macrophage polarization toward M2-like phenotype. The inhibitor of Nrf-2/HO-1 brusatol diminished the effects of riclinoctaose on macrophage polarization. In mice, intravenous injection with riclinoctaose-pretreated bone marrow-derived macrophages also protected against renal ischemia-reperfusion injury. Fluorescence-labeled riclinoctaose specifically bound to the membrane of macrophages. Interfering with mDC-SIGN blocked the riclinoctaose function on M2 polarization of macrophages, consequently impairing the renoprotective effect of riclinoctaose. Our results revealed that riclinoctaose is a potential therapeutic agent in preventing renal ischemia-reperfusion injury.

Concomitant production of value-added products with polyhydroxyalkanoate (PHA) synthesis: A review

The concern over the damaging effects of petrochemical plastics has inspired innumerable researchers to synthesize green plastics. Polyhydroxyalkanoates (PHAs) are promising candidates as they are biodegradable and possess characteristics similar to conventional plastics. However, their large-scale production and market application still have a long way to go due to the high production cost associated. Approaches like using industrial wastes as substrates and developing green strategies for PHA extraction during downstream processing have been investigated to make the process more economical. Recently, PHA production cost was minimized by concomitant synthesis of other valuable bioproducts with PHA. Investigating these co-products and recovering them can also make the process circular bioeconomic. Therefore, the paper attempts to review the recent strategies for the simultaneous synthesis of value-added bioproducts with PHA together with the challenges and opportunities for their large-scale production and applications.

Immunomodulatory effects of four polysaccharides purified from Erythronium sibiricum bulb on macrophages

Four neutral polysaccharides (ESBP1-1, ESBP1-2, ESBP2-1 and ESBP3-1) were successfully purified from the water extracted crude polysaccharides of Erythronium sibiricum bulbs through the combination of DEAE Sepharose CL-6B and Sephadex G-100 chromatography; their average molecular weights were 1.3 × 10⁴, 1.7 × 10⁴, 9.4 × 10⁵ and 4.1 × 10⁵ Da, respectively. Monosaccharide component analysis indicated that ESBP1-1 and ESBP1-2 were mainly composed of glucose (Glc). ESBP2-1 was composed of Glc, galactose (Gal) and arabinose, with a molar ratio of 24.3:1.1:1, whereas ESBP3-1 comprised Glc and Gal at a molar ratio of 14.8:1. In-vitro study showed that all of the four polysaccharides were able to considerably promote the proliferation and neutral red phagocytosis of RAW 264.7 macrophage cell. They could also stimulate the production of the cell lines' secretory molecules [nitric oxide, tumour necrosis factor-α (TNF-α) and interleukin-1β (IL-1β)] in a dose-dependent manner. However, ESBP1-2 was not included in IL-1β. Overall, these results suggested that polysaccharides from E. sibiricum bulbs can be developed as immunomodulatory ingredients for complementary medicines or functional foods. However, further animal or clinical studies are required.

Preparation and Gut Microbiota Modulatory Property of the Oligosaccharide Riclinoctaose

In relation to available polysaccharides, oligosaccharides have a low molecular weight, less viscosity, and complete water solubility. These properties endow oligosaccharides with significant biological properties including the microbiota regulation ability. In this study, a homogeneous oligooctasaccharide, riclinoctaose, was biosynthesized from succinylglycan riclin by enzymatic degradation. Monosaccharide composition, Fourier-transform infrared, electrospray ionization mass spectrometry, and nuclear magnetic resonance spectrometry analysis indicated that riclinoctaose is an oligooctasaccharide consisting of one galactose and seven glucose residues, with a pyruvate group linked to the terminal glucose residue. The effects of dietary riclinoctaose on the gut microbiota of mice were evaluated. We found that the dietary riclinoctaose significantly altered intestinal microbiota with the increased growth of beneficial intestinal bacteria including Bifidobacteria and Lactobacillus and decreased the abundance of pernicious bacteria such as Gammaproteobacteria. The level of short-chain fatty acids (SCFAs) was significantly elevated in the riclinoctaose cecum. Our results suggested that riclinoctaose as a prebiotic may have a great potential application in functional foods.