Water-soluble Heteropolysaccharide Research Articles

Anti-aging activities of neutral and acidic polysaccharides from Polygonum multiflorum Thunb in Caenorhabditis elegans

Polygonum multiflorum Thunb (PM) is used to slow the aging process. Although polysaccharides are a major constituent of PM, their anti-aging properties have not been thoroughly investigated. Therefore, this study aimed to examine the anti-aging effects of polysaccharides extracted from PM using the Caenorhabditis elegans (C. elegans) model. Two types of water-soluble heteropolysaccharides, namely a neutral polysaccharide (RPMP-N) and an acidic polysaccharide (RPMP-A), were obtained from PM. Their structures were elucidated by various methods. The effects of these polysaccharides on the lifespan, levels of antioxidants, and activities of antioxidant-related enzymes in C. elegans were also evaluated. The results showed that RPMP-A had higher GalA content compared with RPMP-N. The average molecular weights of RPMP-N and RPMP-A were 245.30 and 28.45 kDa, respectively. RPMP-N is a α-1,4-linked dextran as the main chain, and contains a small amount of branched dextran with O-6 as the branched linkage site；RPMP-A may be a complex of α-1,4-linked dextran, HG and RG-I. Treatment with RPMP-N and RPMP-A increased the mean lifespan of C. elegans, and significantly regulated oxidative stress. RPMP-A exhibited stronger anti-aging effects compared with RPMP-N. These findings suggest that RPMP-A may be a potent antioxidant and anti-aging component that can be used for developing functional food products and effective dietary supplements.

Structure characterization of novel heteropolysaccharides from Pteridium revolutum with antioxidant and antiglycated activities.

This study aims to analysis the structures of polysaccharides isolated from Pteridium revolutum and their antioxidant and antiglycated activities. Three novel water-soluble heteropolysaccharides, named PRP0, PRP1, and PRP2, were isolated from P. revolutum. The average molecular weight was determined by high performance gel permeation chromatography analysis as 1.04×106, 8.39×105, and 7.37×105 Da, respectively. Their structures were characterized using physicochemical and spectroscopic methods. The antioxidant and antiglycated activities were assayed in vitro. PRP0, PRP1, and PRP2 consist of l-Ara, l-Rha, d-Man, d-Xyl, d-Fuc, d-Gal, and d-Glc in different proportions. PRP1 mainly has a backbone of (1→3,6)-linked d-Man and (1→3)-linked d-Gal on main chain. PRP2 is mainly composed of (1→2,4)-linked d-Man and (1→3)-linked d-Gal on main chain. All polysaccharides have strong scavenging power on 2,2-difenil-1-picril-hidrazil and hydroxyl radicals and significantly antiglycated activity in Bovine serum albumin-Glucose model, which showing that the polysaccharides have potential application value on the functional food.

The extraction, structure characterization and hydrogel construction of a water-insoluble β-glucan from Poria cocos

Most reported polysaccharides from Poria cocos (PCPs) in traditional Chinese medicine decoctions were water-soluble heteropolysaccharides while the water-insoluble PCPs were scarcely researched due to the poor water-solubility. In this study, a water-insoluble polysaccharide with high yield of 59%, and high purity with a glucan content of 98.8%, was isolated by diluted sodium hydroxide at low temperature and coded as PCPA. The chemical structure of PCPA was identified as a liner β-glucan with 1, 3-linked glycosidic bond by the fourier infrared spectrum (FT-IR), ion chromatography (ICP), gas chromatography and mass spectrometry (GC-MS), and nuclear magnetic resonance (NMR) measurements. Importantly, PCPA was successfully used to construct hydrogels (PCPA-Gs) with good thermal stability, water retention ability and swelling property through simple physical cross-linking, due to the abundance of hydroxyl groups on glucan chains. Moreover, the rheology analysis of PCPA-Gs showed a rapid transition between gel and sol as well as the shear-thinning property. The hydrogel developed in this study holds promise for applications in the food, pharmaceutical, and cosmetic fields.

Extraction and Characterization of Galactomannan from Nipa Palm Fruit (Nypa fruticans W.)

The main objective of this research was to characterize the galactomannan from Nipa palm fruit. The galactomannan, a water-soluble heteropolysaccharide was extracted from nipa palm fruit with the different condition. Different condition referred to used nipa palm fruit without drying as fresh nipa palm fruit (GalFN) and nipa palm which is done by drying as dry nipa palm fruit (GalDN). Extraction method used is aqueous extraction followed by precipitation with ethanol. Polysaccharide was studied in detail for its chemical and functional characterization. The result suggests that the different condition of nipa palm fruit (GalFN and GalDN) does not have a significant impact (p>0.05) on the extraction yield, solubility (25°C and 80°C) and oil-holding capacity (OHC), yet it has a significant effect (p<0.05) on the whiteness degree and water-holding capacity (WHC). The physicochemical properties of GalFN and GalDN obtained respectively are as follows: extraction yield (6.34% and 6.13%), whiteness degree (78.20 and 70.10), solubility (34.93% and 35.73%) at 25°C (71.13% and 72.73%) at 80°C, WHC (295.03 and 316.97 g water/100 g gum), OHC (81.70 and 86.20 g oil/100 g gum). It was concluded that between GalFN and GalDN there were significantly differences in whiteness degree, water holding capacity, viscosity on Concentration of Nypa gum 1% and 2%.

Structure elucidation, immunomodulatory activity, antitumor activity and its molecular mechanism of a novel polysaccharide from Boletus reticulatus Schaeff

A new water-soluble heteropolysaccharide with a molecular weight of 15 kDa was isolated from the fruiting bodies of Boletus reticulatus Schaeff. Structural characterization results revealed that B. reticulatus Schaeff polysaccharide (BRS-X) had a backbone of 1,6-linked α-D-galactose and 1,2,6-linked α-D-galactose which branches were mainly composed of a terminal 4-linked β-D-glucose and the ratio of D-galactose and D-glucose was 5:1. Bioactivity assays indicated that BRS-X displayed a strong proliferative activity in T cells and B cells and promoted the secretion of immunoglobulin G (IgG), IgE, IgD and IgM. In addition, BRS-X could facilitate the proliferation and phagocytosis of RAW264.7 cells and could significantly inhibit the growth of tumors in S180-bearing mice. The results of transcriptome sequencing analysis illustrated that total 46 genes enriched in MAPK and total 34 genes enriched in PI3K/Akt signaling pathways in BRS-X group. The protein VEGF and VEGFR expression were significantly reduced under the treatment with BRS-X. These findings provide a scientific basis for the edible and medicinal value of BRS-X.

Sargassum fusiforme fucoidan ameliorates diet-induced obesity through enhancing thermogenesis of adipose tissues and modulating gut microbiota

Obesity has become a global epidemic. Sargassum fusiforme fucoidan (Fuc) is a group of water-soluble heteropolysaccharides that exhibits a wide range of medicinal functions. It consists of l-fucose and sulfate groups, with l-fucose as the main monosaccharide. This study investigated the therapeutic effects of Fuc on diet-induced obesity (DIO) in C57BL/6J female mice. Fuc significantly alleviated obesity in mice induced by high-fat high-fructose (HFHF) feeding, inhibiting body weight gain, reducing fat accumulation, and improving hepatic steatosis. In addition, Fuc significantly improved glucose tolerance and insulin sensitivity by enhancing the phosphorylation level of AKT (at Ser473) in the adipose tissues. Mechanistically, although Fuc did not decrease the energy intake in DIO mice, it significantly increased the energy expenditure by up-regulating the expression of uncoupling protein 1 (UCP1) in the adipose tissues. Notably, Fuc also improved the obesity-driven dysbiosis of gut microbiota and decreased the relative abundance of the obesity-related intestinal bacteria. However, Fuc was unable to alleviate DIO-induced metabolic disorders in pseudo-sterile mice. Our findings suggested that Fuc might remodel gut microbiota and exert its weight loss and hypolipidemic effects by increasing the energy expenditure, thus providing a novel perspective for treating obesity and related complications.

Extraction, structure, and activity of polysaccharide from Radix astragali.

Radix astragali polysaccharide (RAP) is a water-soluble heteropolysaccharide. It is an immune promoter and regulator, and has antivirus, antitumor, anti-aging, anti-radiation, anti-stress, anti-oxidation and other activitys. The extraction, separation, purification, structure, activity and modification of RAP were summarized. Some extraction methods of RAP had been introduced, and the separation and purification methods of RAP were reviewed, and the structure and activity of RAP were highly discussed. Current derivatization of RAP was outlined. Through the above discussion that the yield of crude polysaccharides from Radix astragali by enzyme-assisted extraction was significantly higher than that by other extraction methods, but each extraction method had different extraction effects under certain conditions, and the activity efficiency of RAP was also different. Therefore, it is particularly important to optimize the extraction method with known better yield for the study of RAP. In addition, the purification and separation of RAP are the key factors affecting the yield and activity of RAP. At the same time, there are still few studies on the derivatiration of Radix astragali polysaccharide, but the researches in this area are very important. RAP also has many important pharmacological effects on human body, but its practical application needs further study. Finally, studies on the structure-activity relationship of RAP still need to be carried out by many scholars. This review would provide some help for further researches on various important applications of RAP.

Immunoregulatory activity of a low-molecular-weight heteropolysaccharide from Ganoderma leucocontextum fruiting bodies in vitro and in vivo.

The chemical structure of GLP-1, a novel water-soluble heteropolysaccharide purified Ganoderma leucocontextum fruiting bodies, has been characterized in our previous study. This study aimed to investigate the immunostimulatory activity of GLP-1 in vitro and in vivo by using RAW264.7 macrophages and cyclophosphamide-induced immunosuppressed mice model. Results showed that GLP-1 was able to enhance phagocytic activity and promote the production of reactive oxygen species, nitric oxide, tumor necrosis factor-α, interleukin-6, and monocyte chemoattractant protein-1 in RAW264.7 macrophages. Moreover, GLP-1 could activate mitogen-activated protein kinase, phosphatidylinositol-3-kinase/protein kinase B, and nuclear factor-kappa B signaling pathways through toll-like receptor 2 and dectin-1 receptors. Furthermore, GLP-1 increased the thymus index, serum immunoglobulin levels, and percentage of CD3+ T lymphocytes in cyclophosphamide-induced immunosuppressed mice. These results demonstrated that GLP-1 possessed significant immunostimulatory effects in vivo and in vitro and could be developed as an effective immunomodulator for application in functional foods.

Preparation, chemical structure, and immunostimulatory activity of a water-soluble heteropolysaccharide from Suillus granulatus fruiting bodies

A water-soluble heteropolysaccharide (SGP2-1) was purified from Suillus granulatus fruiting bodies by anion-exchange chromatography and gel permeation chromatography. The structural characteristics were analyzed by high-performance gel permeation chromatography, high-performance liquid chromatography, Fourier transform infrared spectroscopy, gas chromatography-mass spectrometry, and nuclear magnetic resonance spectroscopy. The immunostimulatory activity was investigated using RAW 264.7 macrophages. Results showed that SGP2-1 with weight average molecular weight of 150.75 kDa was composed of mannose, glucose, and xylose. The backbone of SGP2-1 was mainly composed of → 4)-α-Glcp-(1→, and the terminal group α-d-Glcp → was linked to the main chain by O-6 position. SGP2-1 could significantly enhance pinocytic capacity, reactive oxygen species production, and cytokines secretion. SGP2-1 exerted immunomodulatory effects through interacting with toll-like receptor 2, and activating mitogen-activated protein kinase, phosphatidylinositol-3-kinase/protein kinase B, and nuclear factor-kappa B signaling pathways. These findings indicated that SGP2-1 could be explored as a potential immunomodulatory agent for application in functional foods.

Protective effects of GLHP from Gracilaria lemaneiformis against UVB-induced photodamage in human immortalized keratinocytes cells and BALB/c mice.

Our previous study showed that the water-soluble heteropolysaccharide extracted from Gracilaria lemaneiformis (GLHP) has excellent anti-inflammation and anti-oxidant properties. This study explored the efficacy of GLHP against skin anti-photoaging in human immortalized keratinocytes (HaCaT) cells and BALB/c mice under UVB irradiation. Cell viability, antiapoptotic, reactive oxygen species (ROS) scavenging activity, mitochondrial membrane potential, and cell wound scratch assays were conducted, as well as assessment of inflammation markers and sun protection factors. The in vitro results showed that GLHP pretreatment significantly inhibited UVB-induced apoptosis, reversed the decrease of cell viability via downregulating the expression of apoptosis-related protein caspase-3, accelerated the migration of HaCaT cells, and promoted wound healing. Notably, the protective effect of GLHP may be associated with the scavenging of ROS and the decrease of mitochondrial membrane potential. Moreover, GLHP pretreatment significantly restrained the upregulation of iNOS (UVB-induced inflammation marker), suppressed the expression of P-ERK and NF-κB, and decreased the activity of MMPs, suggesting that it exerts the therapeutic effects by inhibiting the MAPK/NF-κB signal pathway. Results obtained after conducting the in vivo assay confirmed that GLHP could reverse the UVB-induced increase of epidermal thickness in BALB/c mice. In conclusion, this study shows that GLHP can be utilized as a safer resource in the manufacture of anti-aging cosmetics because it exerts excellent anti-photoaging effects.

Browning Prevention of Flour from Freshly Harvested Porang (Amorphophallus oncophyllus) Tubers through Immersion in Sodium Metabisulfite at Various Times

Porang (Amorphophallus oncophillus) tubers contain multifunctional water-soluble heteropolysaccharides, called glucomannan. Therefore, the quality of porang tuber chips is highly depending on its glucomannan content and physical appearance. The presence of considerable amount of carotene, polyphenoloxidases and tannins in these tubers may cause browning of flour during processing. The purpose of this research was to study the effect of enzymatic anti-browning agent (sodium metabisulfite) concentrations (2, 5 and 7.5%) w/w) and immersion times (30, 60, 90, 120, 150 and 180 minutes) on the degree of whiteness. An increase in the concentration of anti-browning agent solution up to 5% w/w caused significant increase the degree of whiteness of porang flour and quality of porang flour. However, further increase in the concentration of anti-browning agent solution exhibited reduction in the degree of whiteness and quality of porang flour. In addition, a longer immersion time also resulted in a higher degree of whiteness of porang tuber chips. The best browning prevention conditions were through immersion of porang tuber chips in 7.5% w/w sodium metabisulfite solution for 150 minutes, from which a highest degree of whiteness was achieved (81.99).

Computational simulation, surface characterization, adsorption studies and electrochemical investigation on the interaction of guar gum with mild steel in HCl environment

Guar Gum (GG), a water-soluble hetero polysaccharide is used for the interaction study on mild steel (MS) in 0.5 N HCl by weight loss, electrochemical methods, surface monitoring studies, and DFT and MC based quantum chemical calculations. 200 to 800 ppm of the inhibitor was introduced to the medium at 303 to 323 K. The maximum inhibition efficiency (IE) was obtained for 800 ppm of GG. The surface monitoring including FTIR, XPS, FESEM, and AFM studies reveal that GG effectively forms an adsorbed inhibitive layer on the MS surface by substituting pre-adsorbed water molecules and adsorption phenomenon follows the Langmuir model. The computational correlations (DFT and Monte Carlo simulations) justify the experimental observations. Thermodynamic adsorption parameters confirmed that the GG is adsorbed by spontaneous mixed physisorption and chemisorption with tending to physisorption process.

Structural characterization and antioxidant effect of green alga Enteromorpha prolifera polysaccharide in Caenorhabditis elegans via modulation of microRNAs

A water-soluble heteropolysaccharide was isolated and purified from Enteromorpha prolifera by DEAE-52 and Bio-Gel P-2 column chromatography. Fourier transform infrared spectroscopy (FTIR), high performance liquid chromatography (HPLC), multi-angle laser light scattering (MALLS), and nuclear magnetic resonance (NMR) spectroscopy were used to characterize the structure of E. prolifera polysaccharide degradation (EPP-1). Its anti-oxidative activity was determined in Caenorhabditis elegans via modulation of microRNAs. The average molecular weight of EPP-1 was 4.28 kDa. It contained six types of linkage units as →2)-β-d-GlcpA-(1→, →3,6)-β-d-Manp-(1→, →4)-α-d-Glcp-(1→, →6)-β-d-Galp-(1→, β-l-Rhap-(1→, and →4)-β-d-GalpA-(1→. The mean lifespan, ultraviolet-induced oxidative stress, and thermotolerance in C. elegans were improved after treatment of EPP-1. Moreover, EPP-1 significantly increased the total superoxide dismutase levels and decreased the malondialdehyde levels in C. elegans. Intracellular reactive oxygen species accumulation and DNA damage were ameliorated by up-regulation of SKN-1 and DAF-16 expression through miR-48 and miR-51 miR-186 down-regulation. In vivo studies demonstrated that EPP-1 might be applied in functional foods as the antioxidative and anti-ageing ingredient.

Browning Prevention of Chips from Freshly Harvested Porang (Amorphophallus oncophyllus) Tubers through Immersion in Ascorbic Acid Solutions at Various Times

Porang (Amorphophallus oncophillus) tubers contain multifunctional water-soluble heteropolysaccharides, called glucomannan. Therefore, the quality of porang tuber chips is highly depending on its glucomannan content and physical appearance. The presence of considerable amount of carotene, polyphenoloxidases and tannins in these tubers may cause browning of chips and flour during processing. The purpose of this research was to study the effect of anti-browning agent (ascorbic acid) concentrations (2, 5 and 7.5%) w/w) and immersion times (30, 60, 90, 120, 150 and 180 minutes) on the degree of whiteness of porang tuber chips. An increase in the concentration of anti-browning agent solution up to 5% w/w caused significant increase the degree of whiteness of porang tuber chips. However, further increase in the concentration of anti-browning agent solution exhibited reduction in the degree of whiteness of porang tuber chips. In addition, a longer immersion time also resulted in a higher degree of whiteness of porang tuber chips. The best browning prevention conditions were through immersion of porang tuber chips in 5% w/w ascorbic acid solution for 120 minutes, from which a highest degree of whiteness was achieved (79.41).

A Role of Exopolysaccharide Produced by Streptococcus thermophilus in the Intestinal Inflammation and Mucosal Barrier in Caco-2 Monolayer and Dextran Sulphate Sodium-Induced Experimental Murine Colitis.

Exopolysaccharide (EPS) produced by probiotics may play an important role in gastrointestinal disease prevention, including ulcerative colitis. However, there is no literature reporting on the intervention effects of purified EPS. The aim of this study was to investigate the alleviating effect of the purified EPS produced by Streptococcus thermophilus MN-BM-A01 on murine model of colitis induced by dextran sulphate sodium (DSS). A water-soluble heteropolysaccharide (EPS-1) isolated from MN-BM-A01 was composed of rhamnose, glucose, galactose, and mannose in a molar ratio of 12.9:26.0:60.9:0.25, with molecular weight of 4.23 × 105 Da. After EPS-1 administration, the disease severity of mouse colitis was significantly alleviated, mainly manifesting as the decrease of disease activity index and mitigated colonic epithelial cell injury. Meanwhile, pro-inflammatory cytokines levels (tumor necrosis factor-α, interleukin-6, and interferon-γ) were significantly suppressed, the reduced expressions of tight junction protein (claudin-1, occludin, and E-canherin) were counteracted. In addition, the results in vitro showed that EPS-1 protected intestinal barrier integrity from the disruption by lipopolysaccharide in Caco-2 monolayer, increased expression of tight junction and alleviated pro-inflammatory response. Collectively, our study confirmed the protective effects of purified EPS produced by Streptococcus thermophilus on acute colitis via alleviating intestinal inflammation and improving mucosal barrier function.

Structural characterization of a bioactive water-soluble heteropolysaccharide from Nostoc sphaeroids kütz

A water soluble Nostoc sphaeroids kütz polysaccharide (NSKP) was extracted and purified by precipitating hot-water extract from Nostoc sphaeroids kütz with 40% (v/v) ethanol. The yield was 40.10% (w/w), and weight average molecular weight (Mw) was determined as 1.31 × 105 g/mol. Cell culture study showed that NSKP could stimulate the NO release from RAW264.7 macrophages. The ρ value (Rg/Rh) of NSKP was calculated as 1.50, indicating flexible random coils conformation of NSKP in aqueous solution. According to methylation analysis, and 1D & 2D NMR spectra, the molecular structure of polysaccharide NSKP was deduced as below: [Display omitted]

Characterization of mucilages extracted from different flaxseed (Linum usitatissiumum L.) cultivars: A heteropolysaccharide with desirable functional and rheological properties

Flaxseed mucilage is composed of water soluble heteropolysaccharides of high molecular weight representing about 3 to 9% of the total seed. In the present study mucilages were extracted from six Indian flaxseed cultivars and their chemical, functional, microstructural and rheological properties were investigated. The extracted mucilages differed significantly (P < 0.05) in their yield (5.56–6.54%), ash (4.80–7.23%), protein (7.68–12.33%), pentose (0.48–0.80 mg/ml) and total sugar (1.58–3.06 mg/ml) contents. Copper (18.87–148.08 mg/kg) and zinc (15.43–53.43 mg/kg) were found to be the most abundant minerals in mucilages. “LC-2023” cv. mucilage exhibited lower values for lead, chromium and cadmium. The mucilage solutions exhibited high foaming (>40%) and solubility (64.5–69.15% at 80 °C) characteristics. Rheological data revealed shear rate dependent behaviour of aqueous mucilage solutions irrespective of cultivar type and concentration used. Frequency sweep tests demonstrated that at high frequency range investigated, storage modulus was higher than loss modulus thereby suggesting viscoelastic fluid behaviour of flaxseed mucilage. All mucilages exhibited endothermic as well exothermic transitions with high decomposition onset temperatures. Mucilage is of special research interest owing to its desirable functional properties, so the outcomes of the present study could be used to identify cultivars for producing mucilages for a desired end use.

Super Liquid Crystalline Polysaccharides Produced by Ultimately-ecological Microreactors

Cyanobacteria fix carbon dioxide and nitrogen from the atmosphere using solar energy to produce various biomolecules, and thus are regarded as ultimately ecological microreactors. Sacran is a cyanobacterial polysaccharide with a very high molecular weight of 29 Mg/mol, which is extracted from Aphanothece sacrum cyanobacterium mass-cultivated in freshwater environments such as river or spring. Sacran is a water-soluble heteropolysaccharide comprising more than 6 kinds of sugar residues and contains 12% sulfate anionic groups and 27% carboxyls. Sacran has a super-absorbent function of water, which can retain 6000 mL for 1 g specimen, due to very long hydrating chains. The value is much higher than hyaluronic acid or conventional super-absorbent polymers. Sacran exhibits self-orienting behavior in dilute solution at a concentration range over 0.25 wt%, which is quite low when compared with conventional liquid crystalline polysaccharides. Mesogenic helical chains of sacrans have extremely high aspect ratios of 1600 for highly persistent lengths of 32 micrometer. Through the liquid crystallinity, sacran solution shows a shear-thinning behavior and the solution spread over a substrate such as biological skin very efficiently to create a thin layer. Applied on atopic dermatitis skin sacran solution exerts excellent moisturizing effect and anti-itching action.

Extraction, purification and antioxidation of a polysaccharide from Fritillaria unibracteata var. wabuensis

Rich polysaccharides were directly observed in the bulbs of Fritillaria unibracteata var. wabuensis (FUW) using the periodic acid–Schiff (PAS) method and microexamination. An acidic water-soluble heteropolysaccharide (FWPS1-1) was isolated from FUW through ethanol precipitation, decoloration, deproteinization, dialysis and separation using a DE-52 anion-exchange column and a Sepharose G-150 gel filtration column. FWPS1-1 (average molecular weight: ~7.44 kDa) has many branches and long side chains; holds the triple-helix conformation; was composed of mannose (Man), galacturonic acid (GalA), galactose (Gal), xylose (Xyl) and arabinose (Ara) with a molar ratio of 2.62:5.59:10.00:0.76:9.38; and features side chains that may be composed of Ara, Man, Gal and GalA, while the backbone may be composed of Xyl, Ara and Gal. In addition, the backbone of FWPS1-1 mainly consists of α-type glycosidic bonds. Bioactivity tests in vitro showed that the polysaccharide exhibited weak 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity and low ferric reducing antioxidant power (FRAP) but high 2,2-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid)l (ABTS) radical scavenging activity, good Fe(II)-chelating ability and remarkable DNA damage protective activity. FWPS1-1 was the first heteropolysaccharide purified from FUW and showed good antioxidant activity and DNA protective effect. The results confirmed that macromolecule is also bioactive ingredient that requires attention like the small-molecule active compounds in FUW.

Molecular properties and immunomodulatory activities of a water-soluble heteropolysaccharide isolated from Plantago asiatica L. leaves

This study aims at investigating physical–chemical properties of a water-soluble heteropolysaccharide from Plnatago asiatica L. leaves, and its immunomodulatory effects on macrophages RAW264.7 cells. Hot water-extracted crude polysaccharide from the plant leaves (PLLCP) was fractionated into four fractions by DEAE Sepharose Fast Flow eluted with 0.1–0.5 M NaCl solutions. The most abundant fraction (0.3 M NaCl elution), designated PLLP-2, was identified as a heteropolysaccharide with an average molecular weight (Mw) of 3.54 × 104 and composed mainly of Gal (34.4%), GalA (36.5%), Ara (10.1%) and Rha (8.4%). PLLP-2 was an acidic polysaccharide exhibiting inflaky curly aggregation with smooth surface. PLLCP and its main subfraction PLLP-2 displayed immunomodulatory activities by stimulating the production of pro-inflammatory cytokines, including TNF-α and IL-1β in macrophage RAW264.7 cells. These results indicate that the main polysaccharide fraction purified from P. asiatica L. leaves is probably pectin, and have potential immunomodulatory function.