Characterization and immunostimulatory activity of an (1→6)-a-d-glucan from the root of Ipomoea batatas

Areca nut polysaccharide induces M1 macrophage polarization through the NF-κB and MAPK pathways independent of TLR2 and TLR4 signaling

In this study, the structure of Areca nut polysaccharide (ANP) was characterized, and its effects on macrophage activation and the underlying molecular mechanisms were investigated. ANP was identified as a glucan with a molecular weight of 24.5 kDa, and its structure was analyzed using XRD, SEM, FT-IR, methylation, and NMR techniques. The main chain of ANP is composed of →4)-α-D-Glcp-(1 → and →4,6)-α-D-Glcp-(1→, with a branched α-D-Glcp-(1 → chain. Furthermore, the activation of macrophages by ANP was explored. Stimulation of RAW264.7 cells with ANP in vitro increased the expression of inflammatory cytokines (TNF-α and IL-6) and NO levels. Flow cytometry showed that ANP induced M1 macrophage polarization. RNA-seq and Western blot analyses revealed that ANP activated the NF-κB and MAPK pathways. Importantly, TLR2- and TLR4- specific antibodies did not affect ANP-induced M1 polarization, whereas endocytosis inhibitors reduced the production of inflammatory cytokines in ANP-treated macrophages. In conclusion, ANP engages macrophages without interacting with TLR2 and TLR4 receptors, inducing M1 polarization through the NF-κB and MAPK signaling pathways.

The ameliorative effect on chemotherapy-induced injury and tumor immunosuppressive microenvironment of the polysaccharide from the rhizome of Menispermum dauricum DC

Combined medication has attracted increasing attention as an important treatment option for tumors due to the serious adverse effects of chemotherapy. In this study, as a new therapy strategy, a combination treatment of MDP (a polysaccharide from the rhizome of Menispermum dauricum DC.) with cyclophosphamide (CTX) was investigated. The results showed that combination treatment with MDP and CTX exerted a significantly synergistic anti-tumor effect in Lewis tumor-bearing mice, improved CTX-induced emaciation and hair loss, as well as increased the number of leukocytes, erythrocytes, hemoglobin, and platelets in the peripheral blood. In addition, compared with CTX alone, the thymus index and spleen index of the MDP + CTX group were increased, the number of CD3 + T cells, CD8 + T cells, white blood cells and B cells in spleen also increased significantly. MDP could also ameliorate the increase in liver and kidney index caused by CTX. In the Lewis lung cancer model, MDP showed a certain degree of anti-tumor effects, which may be related to its promotion of tumor-associated macrophages (TAMs) to M1 phenotype polarisation, enhancement of the number of T cells in tumor tissues and promotion of Th cells in tumor tissues to Th1 phenotype polarisation, thus alleviating the immunosuppressive microenvironment in tumor tissues. This study laid the foundation for the development of MDP as a polysaccharide drug for the treatment or adjuvant therapy of tumors and has important significance for the further clinical application of polysaccharides.

A Comparative Analysis of Polysaccharides and Ethanolic Extracts from Two Egyptian Sweet Potato Cultivars, Abees and A 195: Chemical Characterization and Immunostimulant Activities

Sweet potato (Ipomoea batatas (L.) Lam.) belongs to family Convolvulaceae. The plant is distributed worldwide and consumed, especially for its edible tubers. Many studies have proved that the plant has variable biological activities such as antidiabetic, anti-cancer, antihypertensive, antimicrobial, and immunostimulant activities. The roots of sweet potatoes are rich in valuable phytochemical constituents that vary according to the flesh color. Our investigation focused on the chemical profiling of two Egyptian sweet potato cultivars, Abees and A 195, using UPLC-QTOF and the analysis of their polysaccharide fractions by GC-MS. Furthermore, we assessed the immunostimulant properties of these extracts in immunosuppressed mice. The study revealed that sweet potato roots contain significant concentrations of phenolic acids, including caffeoylquinic, caffeic, caffeoyl-feruloyl quinic, and p-coumaric acids, as well as certain flavonoids, such as diosmin, diosmetin, and jaceosidin, and coumarins, such as scopoletin and umbelliferone. Moreover, polysaccharides prepared from both studied cultivars were analyzed using GC-MS. Further biological analysis demonstrated that all the tested extracts possessed immunostimulant properties by elevating the level of WBCs, IL-2, TNF, and IFN-γ in the immunosuppressed mice relative to the control group with the highest values in polysaccharide fractions of A195 (the ethanolic extract showed a higher effect on TNF and IFN-γ, while its polysaccharide fraction exhibited a promising effect on IL-2 and WBCs). In conclusion, the roots of the Egyptian sweet potato cultivars Abees and A 195 demonstrated significant immunostimulant activities, which warrants further investigation through clinical studies.

Characterization and bioactivities of exopolysaccharide produced from Azotobacter salinestris EPS-AZ-6

This study involved the extraction of an exopolysaccharide (EPS) from Azotobacter salinestris AZ-6, which was isolated from soil cultivated with leguminous plants. In a medium devoid of nitrogen, the AZ-6 strain displayed a maximum EPS yield of 1.1 g/l and the highest relative viscosity value of 3.4. The homogeneity of the polymer was demonstrated by the average molecular weight of 1.61 × 106 Da and a retention time of 17.211 min for levan. The presence of characteristic functional groups and structural units of carbohydrate polymers has been confirmed through spectroscopic analyses utilizing Fourier-transform infrared (FT-IR) and nuclear magnetic resonance (NMR) techniques. Thermogravimetric analysis (TGA) revealed a noteworthy decrease in weight (74 %) in the temperature range spanning from 260 to 350 °C. X-ray diffraction (XRD) was utilized to verify the crystalline and amorphous characteristics of EPS-AZ-6. The EPS-AZ-6 exhibited significant cytotoxicity against the MCF-7 tumor cell line, as evidenced by an IC50 value of 6.39 ± 0.05 μg/ml. It also demonstrated a moderate degree of cytotoxicity towards HepG-2 cell line, as indicated by an IC50 value of 29.79 ± 0.41 μg/ml. EPS-AZ-6 exhibited potent antioxidant and in vitro antibacterial properties. These characteristics suggest the potential application value of EPS-AZ-6 in the food industry and pharmaceutical applications.

Recent Progress in 1,2-cis glycosylation for Glucan Synthesis

Controlling the stereoselectivity of 1,2-cis glycosylation is one of the most challenging tasks in the chemical synthesis of glycans. There are various 1,2-cis glycosides in nature, such as α-glucoside and β-mannoside in glycoproteins, glycolipids, proteoglycans, microbial polysaccharides, and bioactive natural products. In the structure of polysaccharides such as α-glucan, 1,2-cis α-glucosides were found to be the major linkage between the glucopyranosides. Various regioisomeric linkages, 1→3, 1→4, and 1→6 for the backbone structure, and 1→2/3/4/6 for branching in the polysaccharide as well as in the oligosaccharides were identified. To achieve highly stereoselective 1,2-cis glycosylation, including α-glucosylation, a number of strategies using inter- and intra-molecular methodologies have been explored. Recently, Zn salt-mediated cis glycosylation has been developed and applied to the synthesis of various 1,2-cis linkages, such as α-glucoside and β-mannoside, via the 1,2-cis glycosylation pathway and β-galactoside 1,4/6-cis induction. Furthermore, the synthesis of various structures of α-glucans has been achieved using the recent progressive stereoselective 1,2-cis glycosylation reactions. In this review, recent advances in stereoselective 1,2-cis glycosylation, particularly focused on α-glucosylation, and their applications in the construction of linear and branched α-glucans are summarized.

Insights into the nutritional properties and molecular basis of biosynthesis of amino acids and vitamins of Gastrodia elata offered by metabolomic and transcriptomic analysis

Gastrodia elata Blume (GE), a traditional and precious Chinese medicinal material, has been approved as a functional food. However, understanding GE's nutritional properties and its molecular basis remains limited. Here, metabolomic and transcriptomic analyses were performed on young and mature tubers of G. elata.f.elata (GEEy and GEEm) and G. elata.f.glauca (GEGy and GEGm). A total of 345 metabolites were detected, including 76 different amino acids and their derivatives containing all human essential amino acids (e.g., l-(+)-lysine, l-leucine), 13 vitamins (e.g., nicotinamide, thiamine), and 34 alkaloids (e.g., spermine, choline). GEGm has higher amino acid accumulation than GEEy, GEEm and GEGy, and vitamin contents were also slightly different in all four samples. Implying that GE, especially GEGm, is a kind of excellent complementary food as amino acid nutrition provider. From assembled 21,513 transcripts (genes) based on the transcriptome, we identified many genes that encode enzymes (e.g., pfkA, bglX, tyrAa, lysA, his B, aroA), which are responsible for the biosynthesis of amino acids and enzymes (e.g., nadA, URH1, NAPRT1, punA, rsgA) that related to vitamins metabolism. A total of 16 pairs of the differentially expressed genes (DEG) and differentially accumulated metabolites (DAM) (e.g., gene-tia006709 coding GAPDH and l-(+)-arginine, and gene-tia010180 coding tyrA and l-(+)-arginine) and three DEG-DAM pairs (e.g., gene-tia015379 coding NadA and nicotinate d-ribonucleoside) show significant similar positive or negative correlation based on three, and two comparisons of GEEy vs. GEGy, GEGy vs. GEGm, GEEy vs. GEGy and GEEm vs. GEGm, which involved into amino acid biosynthesis, and nicotinate nicotinamide metabolism, respectively. These results prove that the enzyme coded by these DEG promotes (positive correlation) or inhibits (negative correlation) the biosynthesis of parallel DAM in GE. Overall, the data and corresponding analysis in this study provide new insights into the nutritional properties of GE and the related molecular basis.

Biochemical characterization and anti-cancer activity of tangential flow filtration system assisted purification of fucoglucan from Laminaria japonica

Polysaccharide from Laminaria japonica (LJPS) exhibits multiple biological functions. However, we found that crude LJPS doesn't show good anti-lung cancer activity in this study. We therefore used tangential flow filtration (TFF) system to optimize the anticancer activity of LJPS. We divided the crude LJPS into two fractions by TFF system with a 10 kDa filter and denoted as retentate (10K-R) and filtration (10K-F). The chemical assay revealed that the main molecular mass of 10K-R and 10K-F is about 985 and 3 kDa, respectively. The main components of 10K-R include fucose (19.3 %), and glucose (59.5 %); while glucose (88.6 %) is a major component of 10K-F. Biological functions showed that 10K-R but not 10K-F inhibited the viability and mobility of cancer cells. 10K-R downregulated expressions of transforming growth factor β receptor and Slug, and inhibited intracellular signaling molecules, including FAK, AKT, ERK1/2, and Smad2. This study is the first concept to purify the polysaccharide by TFF system and showed the potential mechanism of 10K-R inhibited cancer cells.

Emerging Issues on Tropane Alkaloid Contamination of Food in Europe

The occurrence of tropane alkaloids (TAs), toxic plant metabolites, in food in Europe was studied to identify those TAs in food most relevant for human health. Information was extracted from the literature and the 2016 study from the European Food Safety Authority. Calystegines were identified as being inherent TAs in foods common in Europe, such as Solanum tuberosum (potato), S. melongena (eggplant, aubergine), Capsicum annuum (bell pepper) and Brassica oleracea (broccoli, Brussels sprouts). In addition, some low-molecular-weight tropanes and Convolvulaceae-type TAs were found inherent to bell pepper. On the other hand, atropine, scopolamine, convolvine, pseudotropine and tropine were identified as emerging TAs resulting from the presence of associated weeds in food. The most relevant food products in this respect are unprocessed and processed cereal-based foods for infants, young children or adults, dry (herbal) teas and canned or frozen vegetables. Overall, the occurrence data on both inherent as well as on associated TAs in foods are still scarce, highlighting the need for monitoring data. It also indicates the urge for food safety authorities to work with farmers, plant breeders and food business operators to prevent the spreading of invasive weeds and to increase awareness.

Structure Characterization, Immunological Activity, and Mechanism of a Polysaccharide From the Rhizome of Menispermum dauricum DC

The purpose of this study was to investigate the structural characterization and immunological activity in vitro and in vivo of a polysaccharide from the rhizome of Menispermum dauricum. A new polysaccharide named MDP was isolated from the rhizome of Menispermum dauricum by hot water extraction, ethanol precipitation, anion-exchange, and gel-filtration chromatography. MDP was homogeneous and had a molecular weight of 6.16 ×103 Da, and it was an α-D-glucan containing a (1 → 6)-linked backbone, with a glucosyl residue at the C-3 position along the main chain. MDP exhibited immunological activity in vitro, which could significantly promote the proliferation and phagocytosis of RAW264.7 cells and the release of TNF-α and IL-6 factors. For immunological activity in vivo. MDP could significantly increase the thymus and spleen indices, enhance the macrophage function, increase the level of cytokine (IL-6 and TNF-α) and immunoglobulin IgM in the serum and regulate T lymphocyte subsets. Furthermore, MDP elevated the expression of the critical nodes in the TLR4-MyD88 signaling pathways in vivo. These results support the concept that MDP may exhibit immunological activity through TLR4-MyD88 signaling pathway in vivo.

Hepatic antioxidant activity, immunomodulation, and pro-anti-inflammatory cytokines manipulation of κ-carrageenan (κ-CGN) in cobia, Rachycentron canadum against Lactococcus garvieae

The effects of dietary k-Carrageenan (k-CGN) at 10, 20, and 30 g kg^-1 on growth rate, hemato-biochemical indices, innate-adaptive parameters and modification of pro- and/or anti-inflammatory cytokines and chemokines pathway in cobia, Rachycentron canadum against Lactococcus garvieae is reported. The weight gain (WG) increased substantially (P < 0.05) in all k-CGN treated groups; the specific growth rate (SGR) was significant in healthy uninfected normal (HuN) and L. garvieae challenged (LaC) groups fed with 20 g kg^-1k-CGN diet on 45 and 60 days. The white blood cell (WBC) counts, total protein (TP) level, total anti-oxidant (T-AOC), catalase (CAT), and glutathione (GSH) activities increased significantly when fed with 20 g and 30 g kg^-1k-CG diets on 45th and 60th day. The immunological parameters such as phagocytic (PC) index and the activity of phagocytic (PC), respiratory burst (RB), superoxide dismutase (SOD), alternate complement pathway (ACH₅₀), and lysozyme (LZM) were significantly enhanced with all k-CG diets in 45 and 60 days of treatment. No cumulative mortality (CM) in HuN group fed by control or any k-CGN diets. CM was 5% in LaC group fed with 20 g kg^-1k-CGN diet whereas in LaC groups fed with 10 g and 30 g kg^-1k-CGN diets the CM was 10%. The interleukin 1 beta (IL-1β) and tumor necrosis factor alpha (TNFα) pro-inflammatory cytokines mRNA transcripts were one-fold high (P < 0.05) in both HuN and LaC group fed all k-CGN enriched diets on 45 and 60 days. Similarly, IL-18 and TLR2 mRNA was one-fold high expression in both groups fed the 20 g and 30 g kg^-1k-CGN enriched diets on 45 or 60 days. Interferon gamma (IFNγ) and interferon regulatory factor 3/7 (IRF3/IRF7) mRNA transcripts did not change with any diet. IL-6, IL-10, and IL-11 mRNA were one-fold high expressions in both groups fed the 20 g and 30 g kg^-1k-CGN enriched diets on 45 and 60 days. However, the expression of CC1, CC3, and CCR9 pro-inflammatory chemokines mRNA did not vary with any control or k-CGN enriched diets. The results indicate that diet enriched with k-CGN at 20 g kg^-1 significantly influences the growth, antioxidant and innate-adaptive immune performance, and pro-anti-inflammatory cytokines and chemokines regulation in cobia against L. garvieae.

In vitro immunomodulatory activity of water-soluble glucans from fresh and dried Longan (Dimocarpus longan Lour.)

Longan (Dimocarpus longan Lour.) is a seasonal tropical fruit used by Chinese medicine in both fresh and dried pulp forms. Their polysaccharides have been reported to have biological activity. However, their composition and immune activity have not yet been disclosed. To fulfil this aim, hot water-soluble polysaccharides of fresh and dried longan pulp were fractionated according to their molecular weight by ultrafiltration (10, 50, 100 kDa cut off). The main polysaccharides recovered were 1,6-linked glucans branched at O-3 (4-8%), O-2 (1%), O-2,4 (0.1%), and O-3,4 (0.1%). The drying process promotes the solubility of the polysaccharides. These glucans from fresh and dried longan pulp have immunomodulatory activity, shown by in vitro phagocytosis, NO, TNF-α, and IL-6 macrophages production assays. They showed also to inhibit the inflammatory response induced by LPS. The immunological activity of these glucans seems to have different responses dependent on their molecular weight, related to the immune regulatory pathways.

Structural characterization and immunomodulatory activities of two polysaccharides from Rehmanniae Radix Praeparata

The structures and immunomodulatory activities of two polysaccharides (SDH-WA and SDH-0.2A) from Rehmanniae Radix Praeparata (RRP) were investigated. RRP crude polysaccharide was obtained by water extraction and purified. Ion chromatography, high-performance gel permeation chromatography, Fourier-transform infrared spectroscopy, methylation analysis, gas chromatography-mass spectrometry, and nuclear magnetic resonance were used to characterize the polysaccharides. The main chain of SDH-WA was →6)-α-D-Galp-(1→6)-α-D-Galp-(1→5)-α-L-Araf-(1→3,5)-α-L-Araf-(1→, terminal sugar residue α-L-Araf-(1→ linked to residue →3,5)-α-L-Araf-(1→ on the main chain by an O-3 bond. The other two terminal sugar residues α-D-Galp-(1→ and →6)-β-D-Galp were linked to the end of the main chain. The main chain of SDH-0.2A was →2,4)-α-L-Rhap-(1→4)-α-D-GalpA-(1→. Three branched chains α-D-Galp-(1→6)-α-D-Galp-(1→5)-α-L-Araf-(1→3,5)-α-L-Araf-(1→, →3,6)-β-D-Galp-(1→5)-α-L-Araf-(1→, and →4)-β-D-Galp-(1→5)-α-L-Araf-(1→ were linked to the main chain residue →2,4)-α-L-Rhap-(1→ by an O-2 bond. Three terminal sugar residues α-D-Galp-(1→, α-L-Araf-(1→, and →6)-β-D-Galp were linked to the end of the chain. Both polysaccharides showed no cytotoxic effects on and significantly promoted the phagocytic activity of RAW264.7 cells. They dose-dependently improved lysozyme activity and stimulated the production of TNF-α and IL-6 by RAW264.7 cells, but attenuated the secretion of lysozymes, TNF-α, IL-6, IL-1β, and nitric oxide by lipopolysaccharide-induced RAW264.7 cells. The present studies suggest that PRR polysaccharide is a valuable source with immunomodulating.

A comprehensive review on α-D-Glucans: Structural and functional diversity, derivatization and bioapplications

Glucans are the most abundant natural polysaccharides across the living kingdom with tremendous biological activities. Now a days, α-D-glucans are gaining importance as a prebiotics, nutraceuticals, immunostimulants, antiproliferative agents and biodegradable polymers in pharmaceutical and cosmetic sectors. A wide variety of bioresources including bacteria, fungi, lichens, algae, plants and animals produce α-D-glucans either as an exopolysaccharide (EPS) or a cell wall component or an energy storage polymer. The α-D-glucans exhibit great structural and functional diversity as the type of linkage and percentage of branching dictate the functional properties of glucans. Among the different linkages, bioactivities are greatly confined to the α-D-(1 → 3) linkages whereas starch and other polymers consisting of α-D-(1 → 4) (1 → 6) linkages are specific for food and pharmaceutical applications. However, the bioactivities of the α-D-(1 → 3) glucans in native form is limited mainly due to their hydrophobic nature. Hence several derivatization techniques have been developed to improve the bioavailability as well as bioactive features such as antiviral, antimicrobial, anti-inflammatory, antioxidant, immunomodulatory and antitumor properties. Though, several reports have presented about α-D-glucans, still there is an ambiguity in terms of their structure among different natural sources and moreover no comprehensive information was available on their derivatization techniques and application potential. Therefore, the present review summarizes distinct description on diverse sources, type of linkages, derivatization techniques as well as the application potential of the native and modified α-D-glucans.

β-Glucans as a panacea for a healthy heart? Their roles in preventing and treating cardiovascular diseases

Cardiovascular diseases (CVDs) are the leading cause of death worldwide. Factors increasing the risks for CVD development are related to obesity, diabetes, high blood cholesterol, high blood pressure and lifestyle. CVD risk factors may be treated with appropriate drugs, but prolonged can use cause undesirable side-effects. Among the natural products used in complementary and alternative medicines, are the β-ᴅ-glucans; biopolymers found in foods (cereals, mushrooms), and can easily be produced by microbial fermentation. Independent of source, β-glucans of the mixed-linked types [(1 → 3)(1 → 6)-β-ᴅ-glucans - fungal, and (1 → 3)(1 → 4)-β-ᴅ-glucans - cereal] have widely been studied because of their biological activities, and have demonstrated cardiovascular protective effects. In this review, we discuss the roles of β-ᴅ-glucans in various pathophysiological conditions that lead to CVDs including obesity, dyslipidemia, hyperglycemia, oxidative stress, hypertension, atherosclerosis and stroke. The β-glucans from all of the sources cited demonstrated potential hypoglycemic, hypocholesterolemic and anti-obesogenicity activities, reduced hypertension and ameliorated the atherosclerosis condition. More recently, β-glucans are recognized as possessing prebiotic properties that modulate the gut microbiome and impact on the health benefits including cardiovascular. Overall, all the studies investigated unequivocally demonstrated the dietary benefits of consuming β-glucans regardless of source, thus constituting a promising panaceutical approach to reduce CVD risk factors.

Structural characterization of Lanzhou lily (Lilium davidii var. unicolor) polysaccharides and determination of their associated antioxidant activity

BACKGROUD

The Lanzhou lily (Lilium davidii var. unicolor) is the only Lilium species that is used for both culinary and medicinal purposes in China. Its bulbs contain various bioactive substances, such as polysaccharides, saponins and colchicine. Lanzhou lily polysaccharides are known to have anti-immunity, anti-tumor and anti-oxidation functions.

RESULTS

The present study used a Box-Behnken design to optimize the ultrasound-assisted extraction of Lanzhou lily polysaccharides. Compared to other enzymes, trypsin significantly increased the polysaccharide yields, whereas the protein content of polysaccharides extracted with trypsin was the lowest. Monosaccharide mainly includes glucose (> 50%) and mannose (> 10%). 1,1-Diphenyl-2-picrylhydrazyl radical scavenging activity, chelating activity, total antioxidant capacity and hydroxyl radical scavenging activity of Lanzhou lily polysaccharides extracted with trypsin were stronger than those extracted without enzymes (control). Structural characteristics of Lanzhou lily polysaccharides extracted with trypsin and extracted without enzymes were characterized by scanning electron microscopy and nuclear magnetic resonance spectroscopy. When water extracted polysaccharide and trypsin extracted polysaccharide concentrations were 200 μg mL^-1 , Raw264.7 proliferation rates were 101.69% and 159.41%, respectively.

CONCLUSION

The Lanzhou lily polysaccharide was identified as α-(1 → 6)-d-glucan. Consequently, the effects of both potential antioxidant and proliferative activity of trypsin are significant. © 2020 Society of Chemical Industry.

Therapeutic potential of IBP as an autophagy inducer for treating lung cancer via blocking PAK1/Akt/mTOR signaling

Lung cancer is the most frequent and fatal malignancy in humans worldwide, yet novel successful drugs for control of this disease are still lacking. Ipomoea batatas polysaccharides (IBPs) have been implicated in inhibiting diverse cancer types, but their functions in mitigating lung cancer are largely unknown. In this study, we identify a role of IBP in inhibiting lung cancer proliferation. We found that IBP significantly impedes the proliferation of lung cancer cells by inducing cytostatic macroautophagy both in vitro and in vivo. Mechanistically, IBP specifically promotes ubiquitination-mediated degradation of PAK1 (p21-activated kinase 1) and blocks its downstream Akt1/mTOR signaling pathway, leading to increased autophagic flux. In lung cancer xenografts in mice, IBP-induced cytostatic autophagy suppresses tumor development. Through site-directed mutational analysis, the underlying signaling augments ubiquitination via PAK1-ubiquitin interaction. Collectively, this work unravels the molecular mechanism underpinning IBP-induced cytostatic autophagy in lung cancer and characterizes IBP as a potential therapeutic agent for lung cancer treatment.

Plant-Derived Nutraceuticals and Immune System Modulation: An Evidence-Based Overview

Immunomodulators are agents able to affect the immune system, by boosting the immune defences to improve the body reaction against infectious or exogenous injuries, or suppressing the abnormal immune response occurring in immune disorders. Moreover, immunoadjuvants can support immune system acting on nonimmune targets, thus improving the immune response. The modulation of inflammatory pathways and microbiome can also contribute to control the immune function. Some plant-based nutraceuticals have been studied as possible immunomodulating agents due to their multiple and pleiotropic effects. Being usually more tolerable than pharmacological treatments, their adjuvant contribution is approached as a desirable nutraceutical strategy. In the present review, the up to date knowledge about the immunomodulating properties of polysaccharides, fatty acids and labdane diterpenes have been analyzed, in order to give scientific basic and clinical evidence to support their practical use. Since promising evidence in preclinical studies, limited and sometimes confusing results have been highlighted in clinical trials, likely due to low methodological quality and lacking standardization. More investigations of high quality and specificity are required to describe in depth the usefulness of these plant-derived nutraceuticals in the immune system modulation, for health promoting and disease preventing purposes.

Comparison of Physicochemical Characteristics and Macrophage Immunostimulatory Activities of Polysaccharides from Chlamys farreri

To address the structure-activity relationship of Chlamys farreri polysaccharides on their immunostimulatory efficacy, two polysaccharides (CFP-1 and CFP-2) were extracted from Chlamys farreri by hot water extraction, and separated through column chromatography. The isolated CFPs were chemically analyzed to clarify their physicochemical characteristics and cultured with murine macrophage RAW264.7 cells, in order to evaluate their immunostimulatory efficacy. Despite the fact that both CFP-1 and CFP-2 were mainly comprised of glucose lacking the triple-helix structure, as revealed through preliminary physicochemical analyses, obvious differences in regard to molecular weight (Mw), glucuronic acid content (GAc) and branching degree (BD) were observed between CFP-1 and CFP-2. In in vitro immunostimulatory assays for macrophage RAW264.7 cells, it was demonstrated that CFP-2 with larger Mw, more GAc and BD could evidently promote phagocytosis and increase the production of NO, IL-6, TNF-α and IL-1β secretion, by activating the expression of iNOS, IL-6, TNF-α and IL-1β genes, respectively. Hence, CFP-2 shows great promise as a potential immunostimulatory agent in the functional foods and nutraceutical industry, while CFP-1, with lower molecular weight, less GAc and BD, displays its weaker immunostimulatory efficacy, based on the indistinctive immunostimulatory parameters of CFP-1.

Hetero-Polysaccharides Secreted from Dunaliella salina Exhibit Immunomodulatory Activity Against Peripheral Blood Mononuclear Cells and RAW 264.7 Macrophages

Several species of microalgae have been known to produce exopolysaccharides (EPS) with potential immune activity. In the present investigation, ethyl acetate fraction of crude EPS secreted by Dunaliella salina was explored for immunomodulatory activity against peripheral blood mononuclear cells (PBMC) and RAW 264.7 macrophages. Effect of EPS on cell growth and cytokines production were measured using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay and ELISA respectively. Griess reagent was used for measuring the nitric oxide production in RAW 264.7 macrophages. FTIR analysis and mass spectroscopy were carried out for the characterization. Ethyl acetate fraction exhibited dose dependent increase in proliferative index and cytokines production (IFN-γ, TNF-α, TGF-β). At low concentration (250 and 500 µg/mL), it showed growth inhibition and at higher concentration (1000 and 1500 µg/mL), it enhanced the cell growth. Interestingly, the pronounced increased TNF-α production was observed in ethyl acetate fraction treated PBMC cells at higher concentration (750 and 1000 µg/mL) indicating the immunostimulatory effect. In RAW cells, concentration dependent diminished cell growth (IC₅₀ = 691 µg/mL) and nitric oxide production (IC₅₀ = 630 µg/mL) was observed. FTIR analysis showed the presence of polysaccharides due to the detection of hydroxyl (-OH), Carbonyl (C-O) and alkyl (C-H) groups. Mass spectroscopy results revealed ethyl acetate fraction as penta-saccharide (m/z = 887.56 and 886.54) which are confirmed to be hetero-polysaccharides consisting of hexoses and pentoses along with association of ions. These results suggest that penta-saccharide (ethyl acetate fraction) isolated from D. salina may have the potential to be used for therapeutic purpose as immunomodulatory agent.

Gastrodia elata Blume Polysaccharides: A Review of Their Acquisition, Analysis, Modification, and Pharmacological Activities

Gastrodia elata Blume (G. elata) is a valuable Traditional Chinese Medicine (TCM) with a wide range of clinical applications. G. elata polysaccharides, as one of the main active ingredients of G. elata, have interesting extraction, purification, qualitative analysis, quantitative analysis, derivatization, and pharmacological activity aspects, yet a review of G. elata polysaccharides has not yet been published. Based on this, this article summarizes the progress of G. elata polysaccharides in terms of the above aspects to provide a basis for their further research and development.

Immunostimulating and Antimetastatic Effects of Polysaccharides Purified from Ginseng Berry

Ginseng root has been used in traditional oriental medicine for the enhancement of immune system function. The immunostimulatory effects of ginseng berry polysaccharides, however, remain unclear. Effects of polysaccharides from ginseng berry on the activation of natural killer (NK) cells and inhibition of tumors are reported. A crude polysaccharide was isolated from ginseng berry as a ginseng berry polysaccharide portion (GBPP) and was further fractionated using gel filtration chromatography to obtain the three polysaccharide fractions GBPP-I, -II and -III. GBPP-I consisted of mainly galactose (46.9%) and arabinose (27.5%). GBPP-I showed a high dose-dependent anticomplementary activity. Stimulation of murine peritoneal macrophages by GBPP-I showed the greatest enhancement of interleukin (IL)-6 and IL-12 and tumor necrosis factor (TNF)- α production. In addition, an ex vivo assay of natural killer (NK) cell activity showed that oral ( p.o.) administration of GBPP-I significantly increased NK cell cytotoxicity in YAC-1 tumor cells and production of granzyme B. Prophylactic intravenous ( i.v.) and p.o. administration of GBPP-I significantly and dose-dependently inhibited lung metastatic activity in B16BL6 melanoma cells. Depletion of NK cells after injection of rabbit anti-asialo GM1 partially abolished the inhibitory effect of GBPP-I on lung metastasis, indicating that NK cells play an important role in anticancer effects. GBPP-I exerts a strong immune-enhancing activity and can prevent cancer metastasis through activation of NK cells and other immune-related cells.

Advances in Research on Immunoregulation of Macrophages by Plant Polysaccharides

Polysaccharides are among the most important members of the biopolymer family. They are natural macromolecules composed of monosaccharides. To date, more than 300 kinds of natural polysaccharide compounds have been identified. They are present in plants, animals, and microorganisms, and they engage in a variety of physiological functions. In the 1950s, due to the discovery of their immunoregulatory and anti-tumor activities, polysaccharides became a popular topic of research in pharmacology, especially in immunopharmacology. Plants are an important source of natural polysaccharides. Pharmacological and clinical studies have shown that plant polysaccharides have many functions, such as immune regulation, anti-tumor activity, anti-inflammatory activity, anti-viral functions, anti-radiation functions, and a hypoglycaemic effect. The immunomodulatory effects of plant polysaccharides have received much attention. Polysaccharides with these effects are also referred to as biological response modifiers (BRMs), and research on them is one of the most active areas of polysaccharide research. Thus, we summarize immunomodulatory effects of botanical polysaccharides isolated from different species of plants on the macrophage. The primary effect of botanical polysaccharides is to enhance and/or activate macrophage immune responses, including increasing reactive oxygen species (ROS) production, and enhancing secretion of cytokines and chemokines. Therefore, it is believed that botanical polysaccharides have significant therapeutic potential, and represent a new method for discovery and development of novel immunomodulatory medicine.

A new method for α-specific glucosylation and its application to the one-pot synthesis of a branched α-glucan

We have developed a new and highly efficient α-specific glucosylation method based on the synergistic α-directing effects of a TolSCl/AgOTf promoter system and the steric β-shielding or the remote participation of protecting groups at the donor 6-O-position.

Effect of alternan versus chitosan on the biological properties of human mesenchymal stem cells

Alternan α-1,3- and α-1,6-linked glucan, promotes proliferation, migration, and differentiation of human MSCs.

Immune-enhancing effects of polysaccharides from purple sweet potato

Immune-enhancing effects of three kinds of purple sweet potato polysaccharides (PSPPs) including water-soluble polysaccharide (WSP), dilute alkali-soluble polysaccharide (DASP) and concentrated alkali-soluble polysaccharide (CASP) were evaluated. Scanning electron microscope analysis showed that all PSPPs could stimulate the formation of microvilli-like structures in cellular surfaces, which was possibly related to activation of macrophages. Neutral red uptake assay showed that PSPPs could increase the phagocytic activity of cells. High dose (400 μg/mL) of PSPPs could notably augment the level of nitric oxide (NO). ELISA analysis revealed that 200 and 400 μg/mL of PSPPs distinctly elevated the production of IL-1β. Cells received 200 and 400 μg/mL of WSP as well as 400 μg/mL of DASP exhibited higher level of IL-6. Results of animal experiments showed that WSP treatment (400 mg/kg) could promote the secretions of IgA, IgG, IgM and sIgA in both normal and immunosuppressed mice. Moreover, CASP treatment (400 mg/kg) elevated the production of IgM in the serum of normal and immunosuppressive mice, while DASP (400 mg/kg) only improved the secretion of IgM in normal mice. In summary, all three polysaccharides can stimulate immune responses of macrophages and positively regulate adaptive immunity by enhancing the production of immunoglobulins in 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.

Potato freeze-thaw solution enhances immune function and antitumor activity in vivo

Although potato extract, derived from various methods, exhibits anticancer, antiviral and anti-parasite activities in vitro and in vivo, the bioactivity of potato solution remains unclear using the freeze-thaw extraction method granted by the State Intellectual Property Office of China. In the present study, a potato freeze-thaw solution (PFTS) was fed to mice with ascites tumor that were pre-treated with cyclophosphamide. The numbers of peripheral white blood cells (WBCs), macrophage phagocytosis, lymphocyte transformation and survival of mice were measured. While mice injected with cyclophosphamide exhibited decreased counts of peripheral WBCs, treatment of the cyclophosphamide-injected mice with PFTS for 10 days significantly increased the number of peripheral WBCs and reversed WBC counts to the normal level, a comparable effect to that of Ganoderma lucidum. In addition, treatment with PFTS for 20 days significantly enhanced peritoneal macrophage phagocytosis and lymphocyte transformation. Lastly, PFTS was noticed to prolong the survival of tumor-bearing mice when compared with that of control mice. Collectively, these data suggested that PFTS, at least in part, enhances immune function and possesses antitumor activity.

Effects of a sweetpotato protein digest on lipid metabolism in mice administered a high-fat diet

Sweetpotato peptide (SPP) was prepared by enzyme digestion of sweetpotato protein from starch wastewater. Animal experiments assessed the effect of SPP on body weight, abdominal adipose tissue mass, serum lipids and adipocytokines. Body and liver weight and epididymal and mesenteric fat of mice fed a high-fat diet containing 0.5% or 5% SPP for 28 days were significantly lower than control mice. Triglyceride and cholesterol in VLDL and LDL and leptin levels were significantly lower in the serum of SPP-administered mice compared to control mice. Biomarker arrays showed that adiponectin, melanocyte-stimulating-hormone-alpha and neuromedin U were more than 1.5 times higher, while TNF-alpha was about 1.5 times lower in the livers of SPP-administered mice compared to control mice. These results suggest SPP mitigated leptin resistance in mice administered a high-fat diet, and maintained anorexigenic peptide levels. SPP administration may suppress lipogenesis by increasing adiponectin levels and decreasing TNF-alpha levels in adipocytes.

Bioactivities, isolation and purification methods of polysaccharides from natural products: A review

Polysaccharides play multiple roles and have extensive bioactivities in life process and an immense potential in healthcare, food and cosmetic industries, due to their therapeutic effects and relatively low toxicity. This review describes their major functions involved in antitumor, anti-virus, and anti-inflammatory bioactivities. Due to their enormous structural heterogeneity, the approaches for isolation and purification of polysaccharides are distinct from that of the other macromolecules such as proteins, etc. Yet, to achieve the homogeneity is the initial step for studies of polysaccharide structure, pharmacology, and its structure-activity relationships. According to the experiences accumulated by our lab and the published literatures, this review also introduces the methods widely used in isolation and purification of polysaccharides.

Ultrasonic-assisted extraction, structure and antitumor activity of polysaccharide from Polygonum multiflorum

Polygonum multiflorum is a popular Chinese herbal medicine with various pharmacological functions. In this study, the ultrasonic-assisted extraction condition, structural characterization and antitumor activity of a polysaccharide from roots of P. multiflorum were investigated. The ultrasonic-assisted extraction condition was optimized by single-factor experiments and response surface methodology. Results showed that the maximum extraction yield (5.49%) was obtained at ultrasonic power 158W, extraction temperature 62°C, extraction time 80min and ratio of water to material 20mL/g. The obtained crude polysaccharides were further purified to afford a neutral and an acidic fraction. The structure of the main neutral polysaccharide (named PPS with molecular weight of 3.26×10(5)Da) was characterized as a linear (1→6)-α-d-glucan by gas chromatography, Fourier transform-infrared spectroscopy, methylation analysis, 1D and 2D nuclear magnetic resonance. At the concentration of 400μg/mL, the inhibitory ratios of PPS on HepG-2 and BGC-823 cells were 53.35% and 38.58%, respectively. Results suggested this polysaccharide could be a potential natural antitumor agent.

Structural characterization and immunomodulatory activity of Grifola frondosa polysaccharide via toll-like receptor 4–mitogen-activated protein kinases–nuclear factor κB pathways

We isolated a neutral polysaccharide from the fruiting body of a mushroom Grifola frondosa (GFP-A).

Combination of selenium-enriched green tea polysaccharides and Huo-ji polysaccharides synergistically enhances antioxidant and immune activity in mice

BACKGROUND

The aim of this study was to investigate the influence of a combination of selenium-enriched green tea polysaccharides (Se-GTP) and Huo-ji polysaccharides (HJP) on the immune function and antioxidant activity in mice.

RESULTS

The results showed that the indices of spleen and thymus were markedly increased, and the activity of natural killer (NK) cell was promoted in mice treated with the combination of Se-GTP and HJP. The combined treatment of Se-GTP and HJP also reduced the content of tumour necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in splenocytes. In addition, the activities of glutathione peroxidase (GPx) and superoxide dismutase (SOD) were remarkably enhanced, and malondialdehyde (MDA) levels were significantly reduced in mice treated with combination of Se-GTP and HJP. Furthermore, the combined treatment of Se-GTP and HJP increased nuclear factor erythroid 2-related factor (Nrf2) expression at mRNA and protein levels in splenocytes. The effects of the combination treatment of Se-GTP and HJP in mice were stronger than with Se-GTP or HJP treatment alone.

CONCLUSION

Our study suggests that the combined administration of Se-GTP and HJP can synergistically improve immune function and decrease the oxidative stress by enhancing the mechanisms involved in the clearance of free radicals.

Structural Characterization and Immunostimulatory Activity of a Homogeneous Polysaccharide from Sinonovacula constricta

Sinonovacula constricta has been widely used as a health food and medicine in China, Japan, and Korea. In the present study, a water-soluble polysaccharide fraction (SCP-1) was prepared from S. constricta by enzyme-assisted extraction and purification of chromatography with DEAE-52 cellulose anion-exchange column and Sephadex G-100 size exclusion column. On the basis of the analytical results of high-performance liquid chromatography, Fourier transform-infrared spectroscopy, methylation analysis, and NMR spectroscopy, SCP-1 was found to have an average molecular weight of 15.63 kDa and a linear backbone of (1→4)-linked α-D-Glcp residue with one branch, α-D-Glcp, attached to the main chain by a (1→6) glycosidic bond at every five α-D-Glcp units. Furthermore, it was found that SCP-1 could significantly increase the viability of macrophages, enhance the capability of macrophage phagocytosis, increase the activity of acid phosphatase, and promote the production of nitric oxide, mouse tumor necrosis factor (TNF)-α, mouse interferon (IFN)-γ, and mouse interleukin (IL)-1β. The results suggest that SCP-1 possesses potent immunomodulating effect and may be explored as a potential biological response modifier.

Structure-function relationships of immunostimulatory polysaccharides: A review

Immunostimulatory polysaccharides are compounds capable of interacting with the immune system and enhance specific mechanisms of the host response. Glucans, mannans, pectic polysaccharides, arabinogalactans, fucoidans, galactans, hyaluronans, fructans, and xylans are polysaccharides with reported immunostimulatory activity. The structural features that have been related with such activity are the monosaccharide and glycosidic-linkage composition, conformation, molecular weight, functional groups, and branching characteristics. However, the establishment of structure-function relationships is possible only if purified and characterized polysaccharides are used and selective structural modifications performed. Aiming at contributing to the definition of the structure-function relationships necessary to design immunostimulatory polysaccharides with potential for preventive or therapeutical purposes or to be recognized as health-improving ingredients in functional foods, this review introduces basic immunological concepts required to understand the mechanisms that rule the potential claimed immunostimulatory activity of polysaccharides and critically presents a literature survey on the structural features of the polysaccharides and reported immunostimulatory activity.

Purification and characterization of a glucan from Bacillus Calmette Guerin and the antitumor activity of its sulfated derivative

A water-soluble glucan, BCG-PASW, with a molecular weight of 2.10×10(4)Da, was separated from polysaccharide nucleic acid fraction of Bacillus Calmette Guerin (BCG-PSN) using DEAE-52 cellulose and Sephadex G-200 chromatography. Based on gas chromatography-mass spectrometry (GC-MS), fourier transform infrared (FT-IR) spectra, 1D and 2D nuclear magnetic resonance (NMR) spectroscopy techniques (COSY, HSQC and HMBC), BCG-PASW was found to be an α-d-glucan composed of α-d-(1→4)-linked glucopyranosyl residues, with branches at O-6 consisting of non-reducing terminal α-d-Glcp approximately every eight residues. In vitro antitumor activity by MTS method, its sulfated derivative with a substitution degree of 0.59, could inhibite C666-1 nasopharyngeal carcinoma cells growth significantly. The results indicated that the sulfate content play a decisive role in the bioactivities of the polysaccharides.