Comparison of different longan polysaccharides during gut Bacteroides fermentation

The bioactivity of polysaccharide was closely related to its fermentation utilization by gut Bacteroides, and its utilization degree was determined by various gut Bacteroides species and different polysaccharides characteristics. The effects of longan polysaccharide (LP) and LP treated by ultrasonic-assisted hydrogen peroxide for 8 h (DLP-8) on gut Bacteroides growth, and their fermentation utilization were compared. The results of LP and DLP-8 on the proliferation of six Bacteroides species showed that Bacteroides uniformis had the highest proliferation index. In fermentation by B. uniformis, DLP-8 (with a lower molecular weight), the viable count of which was higher than that of LP, was degraded more and especially utilized more glucose and glucuronic acid. The microstructure of the two polysaccharides changed differently during fermentation. Moreover, DLP-8 promoted greater short-chain fatty acids production than LP. These results indicated that the fermentation properties of DLP-8 by B. uniformis were superior to those of LP.

Effects of polysaccharide from hot-compressed steamed Rehmannia glutinosa on the immune system and gut microbiota in an immunosuppressed mice model

In this study, the immunomodulatory effects of polysaccharide obtained by hot-compressed steaming of Rehmannia glutinosa Libosch (HRP) were investigated using both in vitro and in vivo methods. It was found that HRP activated the TLR4/NF-κB signaling pathway, up-regulated the intracellular expression of TNF-α, IL-6 and IL-1β, and induced of innate immune memory in macrophages. We then investigated the effect of HRP on immunosuppressed mice induced by cyclophosphamide (CTX). Surprisingly, HRP improved CTX-induced weight loss and increased the splenic index, alleviated intestinal mucosal damage and hematopoietic insufficiency caused by CTX, as demonstrated by H&E staining. In addition, HRP promoted the expression of key proteins in the TLR4/NF-κB and autophagy pathways in intestinal tissues, thereby enhancing intestinal immune function. Bacterial 16S rRNA gene sequences of colon contents suggested that HRP may alleviate gut microbiota disruption by increasing the populations of Lachnospiraceae and Erysipelotrichaceae while inhibiting Lactobacillaceae. The results of this study show the potential use of HRP as an immunomodulator in functional foods or pharmaceuticals.

Structural Characterization, Rheological Properties, Antioxidant and Anti-Inflammatory Activities of Polysaccharides from Zingiber officinale

The structural characteristics, rheological properties, antioxidant and anti-inflammatory activities of Zingiber officinale polysaccharides (ZOP) and ZOP-1 were studied. The total soluble sugar contents of ZOP and ZOP-1 were 78.6 ± 0.6 and 79.4 ± 0.4%, respectively. Compared with ZOP, ZOP-1 had a larger molecular weight and a more uniform distribution. There were also some differences in the monosaccharide composition between ZOP and ZOP-1. The main monosaccharide of ZOP and ZOP-1 was glucose (Glc) and galactose (Gal), respectively. Ultraviolet visible spectroscopy (UV-Vis) and fourier transform infrared spectra (FT-IR) results showed that the two polysaccharides had the characteristic absorption peaks of polysaccharides and did not contain nucleic acid and protein. They had good thermal stability, trihelix structure and amorphous sheet structure. ZOP and ZOP-1 had obvious differences in microstructure. The surface of ZOP was smooth and the broken structure was compact and stable with angular shape, while the surface of ZOP-1 was uneven with spiral accumulation and not closely arranged. Moreover, ZOP and ZOP-1 were polysaccharides molecular polymers which were entangled by van der waals' force (VDW) between polysaccharides molecules and hydrogen bond association between sugar chains, and both contain α pyranose. At different concentrations, temperature, pH and salt ion concentrations, both ZOP and ZOP-1 had the properties of non-Newtonian fluids, showed shear dilution phenomenon, which had the potential as a texture modifier or thickener in food or biomedicine. Compared with ZOP, ZOP-1 showed superior antioxidant and anti-inflammatory activities in vitro.

Extraction, purification, structure, modification, and biological activity of traditional Chinese medicine polysaccharides: A review

Traditional Chinese medicines (TCM), as the unique natural resource, are rich in polysaccharides, polyphenols, proteins, amino acid, fats, vitamins, and other components. Hence, TCM have high medical and nutritional values. Polysaccharides are one of the most important active components in TCM. Growing reports have indicated that TCM polysaccharides (TCMPs) have various biological activities, such as antioxidant, anti-aging, immunomodulatory, hypoglycemic, hypolipidemic, anti-tumor, anti-inflammatory, and other activities. Hence, the research progresses and future prospects of TCMPs must be systematically reviewed to promote their better understanding. The aim of this review is to provide comprehensive and systematic recombinant information on the extraction, purification, structure, chemical modification, biological activities, and potential mechanism of TCMPs to support their therapeutic effects and health functions. The findings provide new valuable insights and theoretical basis for future research and development of TCMPs.

Extraction, purification, structural features and biological activities of longan fruit pulp (Longyan) polysaccharides: A review

Dimocarpus longan Lour. (also called as longan) is a subtropical and tropical evergreen tree belonging to the Sapindaceae family and is widely distributed in China, Southeast Asia and South Asia. The pulp of longan fruit is a time-honored traditional medicinal and edible raw material in China and some Asian countries. With the advancement of food therapy in modern medicine, longan fruit pulp as an edible medicinal material is expected to usher in its rapid development as a functional nutrient. As one of the main constituents of longan fruit pulp, longan fruit pulp polysaccharides (LPs) play an indispensable role in longan fruit pulp-based functional utilization. This review aims to outline the extraction and purification methods, structural characteristics and biological activities (such as immunoregulatory, anti-tumor, prebiotic, anti-oxidant, anti-inflammatory and inhibition of AChE activity) of LPs. Besides, the structure-activity relationship, application prospect and patent application of LPs were analyzed and summarized. Through the systematic summary, this review attempts to provide a theoretical basis for further research of LPs, and promote the industrial development of this class of polysaccharides.

Comparison of water- and alkali-extracted polysaccharides from Fuzhuan brick tea and their immunomodulatory effects in vitro and in vivo

In the present study, the purpose is to compare the effect of water extraction and alkali-assisted extraction on the structural characteristics and immunomodulatory activity of polysaccharides from Fuzhuan brick tea (FBTPs). The results indicated that water-extracted FBTPs (W-FBTPs) and alkali-extracted FBTPs (A-FBTPs) had similar molecular weights but different monosaccharide compositions, of which A-FBTPs had a higher yield and uronic acid groups corresponding to galacturonic acid (GalA). Moreover, A-FBTPs had stronger ability to promote phagocytic capacity, acid phosphatase activity and nitric oxide (NO) secretion in macrophages in vitro. In the in vivo study, A-FBTPs exhibited a promising effect to adjust the immune imbalance by enhancing the body features, antioxidant activities, immune response and intestinal mucosal barrier in cytoxan (CTX)-induced immunosuppressive mice. Besides, A-FBTP supplementation effectively improved CTX-induced gut microbiota dysbiosis, including promoting the abundance of beneficial bacteria (e.g., Lactobacillus) and short chain fatty acid (SCFA)-producing bacteria (e.g., Lachnospiraceae, Prevotellaceae and Ruminococcaceae), along with reducing the growth of potentially pathogenic microbes (e.g., Desulfovibrionaceae and Helicobacter). These findings suggested that alkaline extraction might be a promising way to obtain high-quality acidic polysaccharides from Fuzhuan brick tea (FBT), and A-FBTPs could be developed as novel potential prebiotics and immunomodulators for further application in food formulations.

A Novel Polysaccharide Isolated From Fresh Longan (Dimocarpus longan Lour.) Activates Macrophage via TLR2/4-Mediated PI3/AKT and MyD88/TRAF6 Pathways

A novel immunomodulatory polysaccharide (LP4) with a molecular weight 6.31 × 10⁴ g/mol was purified from fresh longan pulp. It was composed of mannose, glucose, glucuronic acid, galactose, xylose, arabinose, galacturonic acid, fucose, and rhamnose in a molar percentage of 36:31:10:7:4:4:3:2:2, and mainly linked by (1→6)-β-Man, (1→4)-β-Glc and (1→6)-α-Glc. LP4 can obviously enhance the phagocytosis of macrophages and promote the proliferation of lymphocytes. After treating macrophages with LP4 (12.5–50 μg/ml), the production of IL-1β and TNF-α was significantly increased. These increases of cytokines were suppressed when the TLR2/TLR4 receptors were inhibited by anti-TLR2 and/or anti-TLR4 antibodies. Moreover, the mRNA expression of INOS, AKT, PI3K, TRAF6 and MyD88 was significantly suppressed by TLR2/TLR4 antibodies. These results indicated that LP4 induced macrophage activation mainly via the TLR2 and TLR4-induced PI3K/AKT and MyD88/TRAF6 pathways.

Acute and chronic oral toxicity assessment of longan sugar extracts derived from whole fruit and from fruit pulp in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Longan (Dimocarpus longan Lour.) is one of the most popular subtropical fruits. Various parts of longan, including seeds, pericarp and pulp, have long been used in traditional medicine in China, Thailand and other Asian countries. The pulp has high sugar, vitamin and mineral content as well as bioactive components. The seeds and pericarp have also been reported to contain beneficial polyphenolic compounds. Longan sugar extract from pulp (LGSP) is prepared as a conventional sugar product. Longan sugar extract from whole longan fruit (LGSW) is also offered as a health food and as a medicinal product.

AIM OF THE STUDY

The objective of this study was to identify and compare potential health hazards of both LGSW and LGSP by testing for acute and chronic oral toxicity in rats.

MATERIALS AND METHODS

In acute toxicity testing, an oral dose (20 g/kg) of either LGSW or LGSP was administered to groups of rats. Mortality and clinical signs of toxicity were observed for 24 h, and then daily for a total of 14 days. In the chronic toxicity test, either LGSW (1, 2.5 and 5 g/kg/day) or LGSP (5 g/kg/day) was administered orally for a period of 180 days. After that treatment period, the rats in the satellite groups which received the highest doses of either LGSW or LGSP were observed for an additional 28 days. The rats then underwent clinical observation, body and organ weight measurement, hematological and biochemical analyses, and histopathological examination.

RESULTS

In the acute toxicity study, the oral administration of LGSP or LGSW in either pellet or syrup formulations did not cause mortality or any pathological abnormalities. In the chronic toxicity study, neither LGSW nor LGSP resulted in death or in any changes in behavior of the rats. All hematological and serum biochemical values of both the LGSW- and LGSP-treated groups were within the normal ranges. No histopathological abnormalities of any internal organs were observed.

CONCLUSION

The safety of longan sugar extract made from whole fruit (pulp, seeds and pericarb) is comparable to that of longan sugar extract made from pulp alone.

Glucose-rich polysaccharide from dried 'Shixia' longan activates macrophages through Ca2+ and CR3- mediated MAPKs and PI3K-AKT pathways

A water-soluble glucose-rich polysaccharide from dried 'Shixia' longan pulp (LPsx) has been isolated for the first time, and its structure and immuno-regulatory mechanism were studied. LPsx is a hetero-polysaccharide with the average molecular weight 4102 g/mol. It was mainly consisted of glucose (95.9%), and small proportions of arabinose (2.1%), galactose (1.0%), mannose (0.6%), and xylose (0.4%). As analyzed by NMR, LPsx was mainly composed of (1 → 6)-α-d-glucose and (1 → 6)-β-d-glucose, branched with α-d-glucose-(1→. The immunomodulatory activity study showed that LPsx significantly increased the phagocytosis of macrophages, and strongly promoted the production of NO, IL-1β, IL-6 and TNF-α. Moreover, LPsx could inhibit the inflammatory response induced by lipopolysaccharide. The immuno-regulatory mechanism of LPsx was studied using RNA- sequencing and receptors activity analyses. It was found that LPsx induced macrophage activation via Ca²⁺ and CR3-mediated MAPKs and PI3K-AKT signaling pathways. The results would be helpful for revealing the health promoting mechanism of dried 'Shixia' longan in traditional Chinese medicine.

Isolation, structural elucidation, and immunoregulation properties of an arabinofuranan from the rinds of Garcinia mangostana

In our search for bioactive polysaccharides as immunomodulatory agents, an arabinofuranan (GMP90-1) was purified and characterized from the rinds of Garcinia mangostana L. GMP90-1 (absolute molecular weight: 5.30 × 10³ g/mol) was found to be composed of arabinose, galactose, and rhamnose. The backbone of GMP90-1 was determined as (1→5)-linked α-l-Araf, (1→2,3,5)-linked α-l-Araf, (1→3,5)-linked α-l-Araf, (1→6)-linked β-d-Galp, and (1→2)-linked α-l-Rhap. Conformational analysis revealed GMP90-1 to exist as a rigid rod structure in sodium chloride solution. To explore its potential as immunomodulatory agents, an in vitro cell screening was performed and GMP90-1 was found to significantly enhance the phagocytic uptake of neutral red and improve the secreted level of nitric oxide (NO), interleukin (IL)-6, IL-1β, and tumor necrosis factor-α (TNF-α) of macrophages. Furthermore, the cellular immunomodulatory activities were confirmed by the in vivo zebrafish experiment, which suggested that GMP90-1 with immunomodulatory effects could be considered as a potential immunomodulatory for immune diseases.

Mesona chinensis Benth polysaccharides protect against oxidative stress and immunosuppression in cyclophosphamide-treated mice via MAPKs signal transduction pathways

In this study, the immune responses of Mesona chinensis Benth polysaccharides (MP) in vitro and in vivo were investigated. Results showed that MP presented immunomodulatory activities on macrophages and T lymphocytes in vitro. Compared with the cyclophosphamide (Cy)-induced immunosuppressive mice, the body weights, spleen indexes (3.45 to 4.91) and thymus indexes (0.78 to 1.04) of the mice treated with MP were increased, and the peripheral blood levels were recovered. MP treatment also increased superoxide dismutase, glutathione peroxidase and catalase activities, and reduced malondialdehyde levels to enhance the total antioxidant capacity of Cy-treated mice. In addition, MP significantly elevated IL-2, NO, and IFN-γ secretions of splenic lymphocytes and spleen, while MP mainly exerts an immune effect by regulating T lymphocytes. Furthermore, MP possessed the immunomodulatory activity by up-regulating the phosphorylation levels of proteins factors (c-Jun N-terminal kinase, extracellular regulated protein kinase and p38 kinase) in mitogen activated protein kinases signaling pathways. This study suggested that MP may be explored as a natural immune stimulant for functional food and nutraceutical industries.

Modulating effects of polysaccharides from the fruits of Lycium barbarum on the immune response and gut microbiota in cyclophosphamide-treated mice

In the present study, the effects of Lycium barbarum polysaccharides (LBPS) on immunoregulation and gut microbiota dysbiosis in cyclophosphamide (CTX)-induced mice were investigated to elucidate whether the attenuation of immunosuppression is related to the modulation of the gut microbiota. The results showed that administration of LBPS could protect immune organs (enhancing immune organ indexes and alleviating immune organ damage), enhance the production of immune-related cytokines (IL-2, IL-6, IL-1β, TNF-α and IFN-γ) and prevent the hepatotoxicity in CTX-induced mice. Additionally, LBPS treatment could promote the production of short-chain fatty acids and modulate the composition of the gut microbiota, increasing the relative abundances of Bacteroidaceae, Lactobacillaceae, Prevotellaceae and Verrucomicrobiaceae, which were positively associated with immune traits. The present results indicated that LBPS might regulate the immune response depending on the modulation of the gut microbiota, suggesting that LBPS could be developed as special ingredients for immunoregulation in association with the modulation of the gut microbiota.

Structure characterization and immunomodulatory activity of a new neutral polysaccharide SMP-0b from Solanum muricatum

In the present study, a novel neutral polysaccharide SMP-0b was extracted and purified from the pulp of Solanum muricatum. Monosaccharide composition analysis revealed that SMP-0b was mainly composed of l-arabinose, d-mannose, d-glucose and d-galactose with the molar ratio of 5.31:2.92:42.23:25.38. The weight-average molecular weight and number-average molecular weight of SMP-0b was calculated to be 13.51 kDa and 9.91 kDa respectively through high performance gel permeation chromatography. The structure of SMP-0b was characterized by methylation and NMR analysis. It showed that the backbone chain of SMP-0b was consisted of →4)-β-d-Galp-(1→, →3,6)-β-d-Manp-(1→ and →6)-α-d-Glcp-(1→, and the side chain was composed of α-l-Araf-(1→ and →4)-α-d-Glcp-(1→. In immunomodulation assays in vitro, SMP-0b exhibited good immunomodulatory activity and could significantly stimulate proliferation and NO production of RAW 264.7 macrophage cells. The results suggested that the neutral polysaccharide from Solanum muricatum might have potential as an immunomodulator or supplement in functional food to enhance immunity.

A fructan from Anemarrhena asphodeloides Bunge showing neuroprotective and immunoregulatory effects

A novel polysaccharide, AAP70-1, was isolated from Anemarrhena asphodeloides for the first time. The primary structural analysis revealed that AAP70-1 was composed of glucose and fructose, had an absolute molecular weight of 2720 Da, and contained a (2→6)-linked β-D-fructofuranose (Fruf) backbone and a (2→1,6)-linked β-D-Fruf side chain with an internal α-D-glucopyranose (Glcp) in the form of a neokestose. To explore the potential factors responsible for the medicinally relevant bioactivities of A. asphodeloides, a biological assay was performed. Using flow cytometry analysis, AAP70-1 was experimentally shown to have neuroprotective effects, and it can prevent and ameliorate neurological damage via reducing apoptosis. The immunomodulation assay further revealed that AAP70-1 can significantly improve immune function by promoting phagocytic capacity and the secretion of cytokines (IL-6, IL-1β and TNF-α) in RAW264.7 cells. These results suggest that AAP70-1 has potential as a therapeutic agent for central nervous system diseases or as an immunomodulatory agent.

Effects of a Lysine-Involved Maillard Reaction on the Structure and In Vitro Activities of Polysaccharides from Longan Pulp

The effects of amino acid-involved Maillard reactions (MRs) on the structure and activities of longan pulp polysaccharides (LPs), which were heteropolysaccharides mainly composed of glucose, galactose, mannose, rhamnose, glucuronic acid, ribose, and galacturonic acid, were investigated. The changes of browning degree and molecular weight (Mw) distribution in the MR systems containing LPs and amino acids (lysine, proline, or glycine) indicated that lysine was more active in conjugating with LPs. The MR-modified LPs (MLPs) obtained via a 4 h MR between LPs and lysine showed obvious structural differences from LPs. Specifically, particle-like LPs contained 94% fractions with a Mw less than 7.07 kDa, by contrast, network-like MLPs contained 45% fractions with a Mw larger than 264.1 kDa. Moreover, MLPs showed stronger radical scavenging abilities and macrophage immunostimulating effects, but weaker cancer cell growth-inhibitory abilities. The results indicate that the amino acid-involved MR is a promising method to modify native polysaccharides for better biological properties.

Caulerpa lentilliferapolysaccharides enhance the immunostimulatory activity in immunosuppressed mice in correlation with modulating gut microbiota

Caulerpa lentilliferapolysaccharides could serve as novel prebiotics and immunostimulators, since they improve the immune-related factors and modulate the gut microbiota in cytoxan-induced immunosuppressed mice.

Effects of polysaccharides from purple sweet potatoes on immune response and gut microbiota composition in normal and cyclophosphamide treated mice

Three polysaccharides were extracted from purple sweet potatoes and then administered to normal and cyclophosphamide treated mice by gavage.

Investigation of the Maillard Reaction between Polysaccharides and Proteins from Longan Pulp and the Improvement in Activities

The purpose of this study was to investigate the Maillard reaction between polysaccharides and proteins from longan pulp and the effects of reaction on their in vitro activities. The polysaccharide-protein mixtures of fresh longan pulp (LPPMs) were co-prepared by an alkali extraction-acid precipitation method. They were then dry-heated under controlled conditions for monitoring the characterization of the Maillard reaction by the measurement of the free amino group content, ultraviolet-visible spectrum, Fourier transform infrared spectrum and molecular weight distribution. All the physicochemical analyses indicated the development of the Maillard reaction between polysaccharides and proteins. The in vitro activity evaluation indicated that the Maillard reaction could effectively enhance the antioxidant, antitumor and immunostimulating activities of LPPMs. The enhancement of 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity and ferric reducing antioxidant power displayed both a positive correlation with the reaction time (p < 0.05). LPPMs dry-heated for three days obtained relatively strong inhibitory activity against HepG2 cells and SGC7901 cells, as well as strong immunostimulating effects on the nitric oxide production and tumor necrosis factor α secretion of macrophages. Maillard-type intermacromolecular interaction is suggested to be an effective and controllable method for improving the functional activities of polysaccharides and proteins from longan pulp.

Dietary litchi pulp polysaccharides could enhance immunomodulatory and antioxidant effects in mice

The purpose of this study was to investigate the immunomodulatory and antioxidant activities of litchi pulp polysaccharides (LP) in cyclophosphamide (Cy)-induced mice. The administration of LP (50, 100 and 200mg/kg/d) remarkably enhanced mesenteric lymph node cells proliferation and serum IgA. Moreover, IL-6, TNF-α, IgG and IgM levels in serum were significantly improved in a dose-dependent manner with LP treatment. Dietary LP induced systemic immune responses including stimulating the proliferation of splenocytes, balancing the ratio of spleen lymphocyte subsets, up-regulating the thymus and spleen indices. Thus, we speculate litchi polysaccharides would express their systemic immunomodulatory effects by triggering the intestinal mucosal immunity. Likewise, LP also significantly increased total antioxidant capacity, as well as superoxidase dismutase and glutathione peroxidase activity, while decreasing malondialdehyde levels in the serum and liver. The immunomodulatory activity of LP was accompanied with its antioxidant activity, which might be related with its structure and prebiotic effect. This is a novel study on the relationship between the immunomodulatory and antioxidant activities of litchi polysaccharides.

Preliminary characterization and immunomodulatory activity of polysaccharide fractions from litchi pulp

Two polysaccharide fractions extracted from litchi pulp have immunostimulatory activity.