Water-extractable Polysaccharides Research Articles

Xylan-cellulose core structure of oat water-extractable β-glucan macromolecule: Insight into interactions and organization of the cell wall complex

Water-extractable β-glucan with high molar mass (HM) determines health benefits of oat food. Oat β-glucan was extracted by a standardized in vitro digestion method and co-existing water-extractable polysaccharide (WEP) fraction and its HM-arabinoxylan (HM-AX) subfraction were isolated to identify their highly acid-resistant subunit and investigate molecular interactions between constituent polymers. The WEP and HM-AX samples consisted of arabinoxylans (AXs) (74 and 76 %, respectively), however, cellulose constituted the secondary component (6.6 and 12.8 %, respectively). Multi-detection HPSEC along with specific enzymatic hydrolysis of AXs revealed the presence of the HM-xylan domain (16 and 34 %, respectively) built of numerous single- and multi-component populations with random coil and rod-like conformations, which were embedded in a xylan matrix with spherical conformation and controlled the macromolecular shape. Unlike single-component populations, the multi-component ones were resistant to hydrolytic action of AX-hydrolyzing enzymes and represented the subunits that anchor matrix polysaccharides onto cellulose surface. These results indicate that water-extractable β-glucan macromolecule comprises as integral element a cellulose core with two linking populations, HM-xylan and low molar mass glucomannan, which are surrounded by a feruloylated AX-arabinan-arabinogalactan composite and next laminated by β-glucan matrix. The stiff cellulose-xylan backbone is the basis of HM β-glucan organization, controlled by its cellulose-like segments.

Structural features and in vitro antitumor activity of a water-extracted polysaccharide from Ganoderma applanatum

The structure of GAP-2 was comprehensively analyzed, and its in vitro antitumor activity was preliminarily evaluated.

Structural characterization and bioactivity evaluation of water-extractable polysaccharides from chickpeas (Cicer arietinum L.) seeds.

Two water-extractable polysaccharide fractions designated as CWP (7. 37 × 105 Da) and CWP-0.2 (1.58 × 104 Da) were isolated and purified from chickpea (Cicer arietinum L.) seeds. The chemical structure of the two polysaccharides was characterized by various methods. Monosaccharide composition and methylation analysis showed that CWP was composed of Man and Glc in a molar ratio of 44.6:55.4, and CWP-0.2 was composed of Rha, Ara, Man, Glc, and Gal in a molar ratio of 10.6:23.3:5.2:4.9:56. Further structural characterization indicated that the main chain connection of CWP was → (2-β-d-Fruf-1) n →, and the main chain connection of CWP-0.2 was explored as → 2,4)-α-l-Rhap-(1 → 3)-α-d-Galp-(1 → with the branched chain of → 2,4)-α-l-Rhap-(1 → o-4. Besides, both CWP and CWP-0.2 had antioxidant and immunoregulatory activity in vitro, through scavenging DPPH· and ABTS·+ as well as stimulating production of NO, IL-6, TNF-α and MCP-1 in RAW 264.7 macrophages. CWP-0.2 revealed significantly higher bioactivity than CWP.

Differential responses of polysaccharides and antioxidant enzymes in alleviating cadmium toxicity of tuber traditional Chinese medicinal materials.

Polygonatum cyrtonema Hua (PC) and Bletilla striata (BS) are widely used and planted as tuber traditional Chinese medicinal materials (TCMMs). Cadmium (Cd) is one of the major causes of soil pollution and challenge to the quality and safety of TCMMs. Understanding the absorption and distribution of Cd is important for addressing the risks posed by its residues. As a result, the higher Cd translocation factor (TF) results in the lower Cd bioconcentration factor (BCF) in the PC tuber than that of BS attributed to a lower Cd concentration in the PC tuber, which guaranteed its safe utilization and edible safety under 1 mg·kg-1 Cd soil. Cd stress overall activated peroxidase (POD), catalase (CAT), and water-extractable polysaccharides in PC (PCP1) to exhibit better antioxidation, while the superoxide dismutase (SOD) in BS increased by approximately 206-277% to alleviate more severe oxidative damage. Particularly, Cd induced an increase in PCP1 higher than that of water-extractable polysaccharides of BS (BSP1) by approximately 335% to 1351%. PC exhibited effective strategies for alleviating Cd toxicity, including transferring Cd to nonmedicinal parts, increasing polysaccharides, and synergistically activating the enzymatic antioxidant system. This study expands the application for the safe utilization of low-Cd contaminated soil and provides novel insights for tuber TCMMs to alleviate Cd toxicity.

Proximate composition of the edible part of purple passion fruit and santol and in vitro prebiotic activity of crude polysaccharide extracts

This study aimed to evaluate the functional and prebiotic properties of the edible portions of certain tropical fruits in Thailand, passion fruit and santol. The proximate composition of passion fruit and santol were analysed which total carbohydrate was the major component in both samples. Total dietary fibre of passion fruit and santol was 44.81 and 26.82% (w/w), respectively, with the majority of insoluble dietary fibre. Soluble dietary fibre of both fruits was extracted by hot water and water-extractable polysaccharide was yielded at 16.47% and 25.24% (w/w) for passion fruit and santol, respectively. The functional properties of fruit fibre were informed, with the satisfactory oil holding capacity of santol polysaccharide. The effect of both fruit polysaccharides on proliferation number at 24 hrs was not different from inulin. Prebiotic activity score of fruit polysaccharide was calculated from the growth of Lactobacillus acidophilus and Bifidobacterium longum compared with the growth of the enteric pathogen, Escherichia coli corresponding to -0.25 and -0.23 for passion fruit and 0.10 and -0.01 for santol, respectively. In conclusion, both passion fruit and santol polysaccharide showed a distinct effect on the supportive growth of probiotic bacteria which may be potential candidate ingredient incorporated in probiotic food. From this evidence, the development of fruitbased synbiotics from passion fruit and santol migh be affordable.

Study on Extraction Process of Root of Henry Wood Betony Polysaccharides and Their Antitumor Activity against S180.

We optimized the hot water extraction of polysaccharides from the root of Henry wood betony (RHWPs) using a uniform test and explored their anti-tumor activities in vitro and in vivo. The optimal extraction conditions were as follows: 40 min extraction time, liquid/solid ratio 30 mL/g, 100 min soaking time, two extraction cycles, 100% ethanol concentration, and extraction temperature of 80 °C. The molecular weight distribution of RHWPs with MWs was 228,600 g/mol and 5001 g/mol. The IR spectrum further indicated that RHWPs are acidic polysaccharides containing pyranose and furan rings. The main monosaccharides found in RHWPs were mannose, ribose, l-rhamnose monohydrate, glucuronic acid, galacturonic acid, glucose, galactose, xylose, arabinose, and fucose. RHWPs inhibited the proliferation of S180 tumor cells and induced apoptosis in vitro. Oral administration of RHWPs to tumor-bearing mice significantly inhibited the growth of the S180 xenografts, accelerated apoptosis in tumor cells, and expanded the necrotic regions. Furthermore, RHWPs also markedly increased the levels of TNF-α, IFN-γ, and IL-2 in the sera of tumor-bearing mice, and activated immune cells such as lymphocytes, NK cells, and macrophages, thereby inducing tumor cell apoptosis. Taken together, RHWPs are a promising anti-tumor agent that ought to be explored further.

Structural characteristics of a highly branched and acetylated pectin from Portulaca oleracea L.

The water-extracted polysaccharide from Portulaca oleracea L. mainly consisted of two pectic polysaccharides designated as POWP-H and POWP-L. The POWP-L was rich in linear homogalacturonan with GalA content of 77.6%, while POWP-H might be a rhamnogalacturonan I (RG-I) pectin composed of Rha (15.7%), Ara (31.7%), Gal (42.5%) and GalA (10.1%). The structure of POWP-H was elucidated by partial degradation, methylation analysis combined with GC-MS method and NMR spectroscopy. It had a weight-average molecular weight of 1.2 × 106 g/mol and high degree of branch of 0.57. The presence of abundant arabinogalactan-II and certain galactan side chains in POWP-H was verified by the T-Araf (17.4%), 1,3,6-Galp (11.8%), 1,3-Galp (8.1%), T-Galp (13.4%) and 1,4-Galp (14.3%). The evidence for the RG-I backbone of POWP-H was demonstrated by the structure analysis of its degraded product POWP-H-H, which had the backbone of →4)-α-GalpA-(1 → 2)-α-Rhap-(1 → 4)-α-GalpA-(1 → 2,4)-α-Rhap-(1→ substituted by short side chain of β-Galp-(1 → 4)-β-Galp-(1→ at O-4 position of →2,4)-α-Rhap-(1 → . Moreover, the POWP-H-H was mainly O-acetylated at O-3 position of α-Rhap with 24.8% acetylation degree. In conclusion, POWP-H was mainly the highly branched and acetylated RG-I pectin with relative short RG-I backbone and abundant arabinogalactan II and certain galactan side chains. Besides, it adopted a flexible chain conformation in 0.1 M NaNO3 solution.

Bioactivities of Lentinus polychrous and Ganoderma lucidum (Agaricomycetes) Polysaccharide Extracts.

This study aimed to compare the bioactivities of Lentinus polychrous polysaccharide extracts with Ganoderma lucidum. Three hot water-extracted polysaccharide fractions of L. polychrous (LPE), including immature fruiting bodies (im-LPE), mature fruiting bodies (ma-LPE), and mycelium (my-LPE), were analyzed for their phytochemical contents and bioactivities (e.g., anticancer, antiviral, anti-inflammatory, and immunomodulatory effects) compared with G. lucidum extract (GLE). Although GLE had the highest total phenolic and protein contents and lower carbohydrate content than LPE, im-LPE showed strong inhibition on HepG2 cell proliferation as did GLE. GLE and LPE showed antiviral effects on herpes simplex virus-1 and the relative antiproliferative activity was from im-LPE > my-LPE > ma-LPE. However, im-LPE showed the best protective activity on the viral attachment step with some virucidal effects. Moreover, all LPE showed selective and stronger inhibitory effects on LPS-induced RAW264.7 macrophages than those of GLE on genetic expression. Considering the 50% inhibitory concentration values, my-LPE possessed the strongest inhibitory activity on the expression of cyclooxygenase-2 and inducible nitric oxide synthase. However, ma-LPE had the strongest inhibitory effects on interleukin-1β and tumor necrosis factor-α gene expression. The extracts increased splenocyte proliferation under mycohaemagglutinin induction with a relative order of my-LPE > GLE > ma-LPE = im-LPE. In conclusion, LPE showed positive effects and stronger activity than G. lucidum. L. polychrous may have potential for use as an ingredient in functional foods.

Effects of extracted polysaccharides from a Chlorella vulgaris biomass on expression of interferon-γ and interleukin-2 in chicken peripheral blood mononuclear cells

Polysaccharides isolated from algae species have been shown to have various biological properties including immunomodulatory activities. In the present study, the effects of water-extractable polysaccharides from a Chlorella vulgaris biomass on the expression of immunostimulatory cytokines by chicken peripheral blood mononuclear cells (PBMCs) were evaluated. Extracted polysaccharides were fractionated using a DEAE Sepharose FF column yielding two fractions (F1 and F2). Crude polysaccharide (CP) and fractions mostly consisted of carbohydrates (71.9 to 82.9%), protein (6 to 13.8%), and uronic acids (4.8 to 7.9%). Monosaccharide constituents were predominantly galactose (13.1 to 53.2%), glucose (15.3 to 38.6%), mannose (5.5 to 11.2%), arabinose (5.6 to 20.7%), and rhamnose (5.8 to 14.7%). Crude, F1, and F2 polysaccharides contained 1 or 2 sub-fractions with average molecular weight ranging from 19.2 to 161.1 × 103 g mol−1. Evaluation of immunostimulatory activities of CP and fractions (200 to 1000 μg mL−1) revealed significant effects on PBMC interferon-γ (IFN-γ) and interleukin-2 (IL-2) expression. The most potent immunostimulating fraction F1 was consisted of a homogeneous polysaccharide with relatively low molecular weight (23.9 × 103 g mol−1), low structural compactness, and mixed linkages of (→1)-, (1→3)-, (1→3,6)-galactopyranose and -glucopyranose residues.

Apoptosis induction activity of polysaccharide from Lentinus edodes in H22-bearing mice through ROS-mediated mitochondrial pathway and inhibition of tubulin polymerization.

BackgroundLentinus edodes is a medicinal mushroom widely used in Asian countries for protecting people against some types of cancer and other diseases.ObjectiveThe objective of the present study was to investigate the direct antiproliferation activity and the antitumor mechanisms of water-extracted polysaccharide (WEP1) purified from L. edodes in H22 cells and H22-bearing mice.DesignThe extraction, isolation, purification, and structure determination of the water-soluted L. edodes polysaccharide WEP1 were performed. The growth inhibitory effects of WEP1 on H22 cells and H22-bearing mice were determined by 3-(4,5-Dimethylthiazol-2-Yl)-2,5-Diphenyltetrazolium Bromide (MTT) method and animal studies. Flow cytometry, scanning electron microscopy, and laser scanning confocal microscopy were used to observe the morphological characteristics of apoptotic cells. The levels of intracellular reactive oxygen species (ROS) were detected by flow cytometry using 2’,7’-dichlorofluorescein-3’,6’-diacetate (DCFH-DA). Western blot was used to determine the expressions of cell cycle proteins and apoptosis-related proteins.ResultsResults showed that WEP1 with a molecular weight of 662.1 kDa exhibited direct antiproliferation activity on H22 cells in a dose-dependent manner. In vivo, WEP1 significantly inhibited the growth of tumor at different doses (50, 100, and 200 mg/kg) and the inhibition rates were 28.27, 35.17, and 51.72%, respectively. Furthermore, morphological changes of apoptosis and ROS overproduction were observed in H22 cells by WEP1 treatment. Cell cycle assay and western blot analyses indicated that the apoptosis induction activity of WEP1 was associated with arresting cell cycle at G2/M phase and activating mitochondrial-apoptotic pathway. Besides, WEP1 disrupted the microtubule network accompanied by alteration of cellular morphology.ConclusionResults suggested that the antitumor mechanisms of WEP1 might be related to arresting cell cycle at G2/M phase, inhibiting tubulin polymerization and inducing mitochondrial apoptosis. Therefore, WEP1 possibly could be used as a promising functional food for preventing or treating liver cancer.

Prebiotic Activity of Poly- and Oligosaccharides Obtained from Plantago major L. Leaves

The aim of the present study was to evaluate the prebiotic potential of Plantago major L. leaves water-extractable polysaccharide (PWPs) and its lower molecular fractions. The structure of PWPs was investigated by high pressure anion exchange chromatography (HPAEC), size exclusion chromatography coupled with multi-angle laser light scattering detector (SEC-MALLS) and Fourier-transform infrared (FTIR) spectroscopy. The chemical composition and monosaccharide analyses showed that galacturonic acid was the main monosaccharide of PWPs followed by glucose, arabinose, galactose, rhamnose and xylose. FTIR study indicated a strong characteristic absorption peak at 1550 cm−1 corresponding to the vibration of COO− group of galacturonic acid. The PWPs was subjected to hydrolysis using commercial enzymes to obtain P. major low molecular fraction (PLM) which was successively separated by size exclusion chromatography on Biogel P2. PWPs and PLM were examined for in vitro prebiotic activity using various assays. Results gave evidence for changes in optical density of the bacteria cells and pH of the growth medium. A heterofermentative process with a lactate/acetate ratio ranged from 1:1 to 1:5 was observed. The ability of PLM to stimulate the production of certain probiotic bacteria glycohydrolases and to be fermented by Lactobacillus sp. strains was successfully proved.

Extraction of extracellular polymeric substances (EPS) from red soils (Ultisols)

Extracellular polymeric substances (EPS) have many beneficial functions in soils. Accurate quantification of EPS in soils is crucial. Here, five methods were compared for their suitability for extraction of EPS from Ultisols: hot water extractable polysaccharide (HWEP), hot dilute acid extractable polysaccharide (HDAEP), easily extractable glomalin (EEG), sodium sulfide (SS) and cation exchange resin (CER) method. Humic-acid equivalent (HAE) was used as an indicator for extracellular contamination and ATP for quantifying intracellular contamination from cell lysis. Among the tested methods, CER resulted in EPS extraction with minimal contamination. Therefore, we propose that CER is currently the most appropriate method for extraction of EPS from Ultisols.

Antioxidation, hepatic- and renal-protection of water-extractable polysaccharides by Dictyophora indusiata on obese mice

The present work aimed to investigate the antioxidation, hepatic- and renal-protection of water-extractable polysaccharides (WPS) by Dictyophora indusiata fruiting body on high-fat emulsion-induced obese mice. The structural analysis indicated that WPS was the α-configurational heteropolysaccharide with the major monosaccharides of mannose and glucose, and the polydispersity of 1.77. The in vivo results showed that WPS administration could improve obesity-associated hepatic and renal metabolic impairment, reduce body weight and ameliorate oxidative stress of liver and kidney by down-regulating serum enzyme activities and hepatic lipid levels, stabilizing serum lipid status, enhancing antioxidant abilities and decreasing insulin and leptin resistance. The in vitro experiments showed that WPS had potential abilities to scavenge free radicals. The conclusions demonstrated that WPS might be used as a salutary food and natural medicine for preventing obesity-associated damage and its complications.

Alkali treated antioxidative crude polysaccharide from Russula alatoreticula potentiates murine macrophages by tunning TLR/NF-\u03baB pathway

In our previous research, Russula alatoreticula was demonstrated as a novel species, ethnic myco-food and reservoir of hot water extractable polysaccharides. However, residue after the hydrothermal process still offer plenty of medicinal carbohydrates that could easily be extracted by using alkali solvent. Thus, the present work was attempted to prepare crude polysaccharide using remainder of the conventional method and subsequently a β-glucan enriched fraction, RualaCap, was isolated. The bio-polymers displayed pronounced therapeutic efficacy as evident by radical scavenging, chelating ability, reducing power and total antioxidant capacity. In addition, strong immune-enhancing potential was also observed indicated by augmentation in macrophage viability, phagocytic uptake, nitric oxide (NO) production and reactive oxygen species (ROS) synthesis. Alongside, the polysaccharides effectively triggered transcriptional activation of Toll like receptor (TLR)-2, TLR-4, nuclear factor kappa B (NF-κB), cyclooxygenase (COX)-2, inducible nitric oxide synthase (iNOS), tumor necrosis factor (TNF)-α, Iκ-Bα, interferon (IFN)-γ and interleukin (IL)-10 genes explaining mode of action. Taken together, our results signify possibility of RualaCap as a potent nutraceutical agent and enhance importance of R. alatoreticula especially in the field of innate immune stimulation.

Prebiotic potential of water extractable polysaccharide from red kidney bean (Phaseolus vulgaris L.)

Red kidney bean (Phaseolus vulgaris) is an excellent source of proteins, complex carbohydrates, fermentable fibers, antioxidant, vitamins and minerals loaded with ample of health benefits. This study assesses in vitro prebiotic potential, fecal fermentation and antibiofilm activity of water extractable polysaccharides (RKBWEP) from red kidney bean (Phaseolus vulgaris). RKBWEP exhibited lower digestibility to pretended human gastric juice (1.58%), α-amylase (4.68%) and intestinal fluid (4.03%) hydrolysis than standard fructooligosaccharide as 2.04%, 5.6% & 7.13% respectively. RKBWEP significantly stimulated the growth of standard probiotic bacteria Lactobacillus plantarum and L. fermentum. In vitro batch fecal fermentation of RKBWEP stimulated growth of beneficial gut microbiota especially Bifidobacterium spp. and Lactobacillus spp. after 24 h. Short chain fatty acids (SCFAs) such as acetic acid, propionic acid and butyric acid concentration increased during RKBWEP fermentation and reached maximum of 47.92, 10.32, 6.91 mM after 48 h. Moreover, RKBWEP (40 μg) effectively inhibited Escherichia coli biofilm formation by 79%. Potential prebiotic and biofilm inhibiting property of kidney bean polysaccharide could be explored as novel food grade adjuncts targeted towards synbiotics development.

Development and Gamma Scintigraphy Study of Trigonella foenum-graecum (Fenugreek) Polysaccharide-Based Colon Tablet.

The major concern with the use of some synthetic excipients is their safety towards biological tissues, hence influencing the reliability of products. With the aim to minimize dependency on highly toxic synthetic excipients, the present study was designed to deliver metronidazole (MNZ) into thecolonic region for localized treatment of amoebiasis using natural polysaccharide-based drug delivery. Compression-coated tablets wereprepared using water extractable natural polysaccharide from Trigonella foenum-graecum (FG). Physical properties of the tablets were evaluated and dissolution study was performed at pH1.2, 6.8, and 7.4 with rat cecal material. Results indicate that all batches demonstrated pH-dependent drug release and prevented release into the stomach, allowing traces into the intestine and highest availability into the colon. A significant correlation (r2 = 0.975) was found between the coating levels of extracted polysaccharide and lag time release of drug. Gamma scintigraphy images of in vivo study conducted on human volunteers showed a small intestinal transit time, i.e., 3-5 (4.2 ± 0.4)h and confirmed that thetablets reached the colon within 6-8h. The present study revealed that theFG polysaccharide-based double compression tablets may be promising colon-specific drug carriers withreduced toxic effects of commonly used synthetic excipients.

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.

Immunostimulatory activity of water-extractable polysaccharides from Cistanche deserticola as a plant adjuvant in vitro and in vivo.

A safe and effective vaccine adjuvant is important in modern vaccines. Various Chinese herbal polysaccharides can activate the immune system. Cistanche deserticola (CD) is a traditional Chinese herb and an adjuvant candidate. Here, we confirmed that water-extractable polysaccharides of CD (WPCD) could modulate immune responses in vitro and in vivo. In a dose-dependent manner, WPCD significantly promoted the maturation and function of murine marrow-derived dendritic cells (BM-DCs) through up-regulating the expression levels of MHC-II, CD86, CD80, and CD40, allogenic T cell proliferation, and the yields of IL-12 and TNF-α via toll-like receptor4 (TLR4), as indicated by in vitro experiments. In addition, its immunomodulatory activity was also observed in mice. WPCD effectively improved the titers of IgG, IgG1 and IgG2a and markedly enhanced the proliferation of T and B cells, the production of IFN-γ and IL-4 in CD4+ T cells and the expression level of IFN-γ in CD8+ T cells better than Alum. Furthermore, WPCD could markedly up-regulate the expression levels of CD40 and CD80 on DCs in spleen and down-regulate the Treg frequency. The study suggests that polysaccharides of Cistanche deserticola are a safe and effective vaccine adjuvant for eliciting both humoral immunity and cellular immunity by activating DCs via TLR4 signaling pathway.

Purification, characterization and immunomodulatory activity of water extractable polysaccharides from the swollen culms of Zizania latifolia

The swollen culms of Zizania latifolia is a popular vegetable and traditional herbal medicine mainly consumed in some Asian countries. In our previous study, water extractable polysaccharide (ZLPs-W) and alkali extractable polysaccharide (ZLPs-A) was sequentially prepared from the swollen culms of Zizania latifolia. In vitro cell assay revealed that ZLPs-W without cytotoxicity had higher immunomodulatory activity than ZLPs-A. Therefore, in this study, ZLPs-W was further separated to three purified polysaccharides of ZLPs-W1, ZLPs-W2, and ZLPs-W3 by anion exchange chromatography and size exclusive chromatography in sequence. They were found to be homogeneous polysaccharides in β-type glycosidic linkage. ZLPs-W1 and ZLPs-W2 without triple helix conformation mainly contained Glc in molar percentage of 96.47% and 85.1%, respectively. ZLPs-W3 with triple helix conformation mainly consisted of Man, Rha, GalA, Glc, Gal and Ara in the molar ratio of 10.23:14.14:37.44:17.14:16.54:4.51. In addition, all the three purified polysaccharides could effectively enhanced the proliferation, phagocytosis, and nitric oxide production of murine macrophage RAW 264.7, suggesting that they possessed a potent immunostimulatory activity and could be developed as immunomodulator in medicine or functional food areas.

Molecular characteristics and rheological properties of water-extractable polysaccharides derived from okra (Abelmoschus esculentus L.)

ABSTRACTCompositions, molecular characteristics, and rheological properties of the water-extractable polysaccharides from okra were investigated. The proportions of galacturonic acid and monosaccharides in the refined polysaccharides were 62.47% and 13.47%, respectively. The molecular weight distribution of 717.5 kDa in the crude polysaccharides was removed through a purification process. Okra polysaccharides were pseudo-plastic fluids exhibiting shear thinning behavior. The refined polysaccharides had a higher apparent viscosity (332.15 mL g−1) than the crude polysaccharides (294.69 mL g−1), and exhibited a positive linear correlation with the logarithm of the zero shear viscosity between 1.0% and 4.0%, showed an elastic behavior at a stress of 1 Pa over the frequency range of 1–10 rad/s. When the concentration reduced below 2.0%, the refined polysaccharides showed a predominantly viscous response over the same frequency range. The rheology was greatly affected by their concentrations, indicating water-extractable okra polysaccharides have great potential as a thickening agent in food industry.