Rhamnogalacturonan II from the leaves of Panax ginseng C.A. Meyer as a macrophage Fc receptor expression-enhancing polysaccharide

Green synthesis of metallic nanoparticles using pectin as a reducing agent: a systematic review of the biological activities

CONTEXT

Pectin is a plant heteropolysaccharide that is biocompatible and biodegradable, enabling it to be an excellent reducing agent (green synthesis) for metallic nanoparticles (MNPs). Nevertheless, in the biological industry, pectin has been left behind in synthesising MNPs, for no known reason.

OBJECTIVE

To systematically review the biological activities of pectin synthesised MNPs (Pe-MNPs).

METHODS

The databases Springer Link, Scopus, ScienceDirect, Google Scholar, PubMed, Mendeley, and ResearchGate were systematically searched from the date of their inception until 10^th February 2020. Pectin, green synthesis, metallic nanoparticles, reducing agent and biological activities were among the key terms searched. The data extraction was focussed on the biological activities of Pe-MNPs and reported following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) recommendations for systematic reviews.

RESULTS

A total of 15 studies outlined 7 biological activities of Pe-MNPs in the only three metals that have been explored, namely silver (Ag), gold (Au) and cerium oxide (CeO₂). The activities reported from the in vitro and in vivo studies were antimicrobial (9 studies), anticancer (2 studies), drug carrier (3 studies), non-toxic (4 studies), antioxidant (2 studies), wound healing (1 study) and anti-inflammation (1 study).

CONCLUSIONS

This systematic review demonstrates the current state of the art of Pe-MNPs biological activities, suggesting that Ag and Au have potent antibacterial and anticancer/chemotherapeutic drug carrier activity, respectively. Further in vitro, in vivo, and clinical research is crucial for a better understanding of the pharmacological potential of pectin synthesised MNPs.

Cognition of polysaccharides from confusion to clarity: when the next "omic" will come?

With the accelerated pace of modern life, people are facing more and more health pressure. The study of polysaccharides seemed a good choice as a potential treasure trove. Polysaccharides, one of the four basic substances (proteins, nucleic acids, lipids and carbohydrates) that constitute life activities, are obviously an underrated macromolecular substance with great potential. Compared with protein and nucleic acid, the research of polysaccharides is still in the primary stage. The relationship between structure and function of polysaccharides is not clear. In this review, we highlighted the main methods of extraction, purification and structure identification of polysaccharides; summarized their biological activities including immunoregulation, hypoglycemic, anti-tumor, anti-virus, anti-coagulation, and so on. Particularly, the relationship between their structures and activities was described. In addition, the applications of polysaccharides in health food, medicine and cosmetics were also reviewed. This review can help polysaccharide researchers quickly understand the whole process of polysaccharides research, and also provide a reference for the comprehensive utilization of polysaccharides. We need to standardize the research of polysaccharides to make the experimental data more universal, and take it as important references in the review process. Glycomic may appear as the next "omic" after genomic and proteomic in the future. This review provides support for the advancement of glycomics.

Development of Broad-Spectrum Antiviral Agents-Inspiration from Immunomodulatory Natural Products

Developing broad-spectrum antiviral drugs remains an important issue as viral infections continue to threaten public health. Host-directed therapy is a method that focuses on potential targets in host cells or the body, instead of viral proteins. Its antiviral effects are achieved by disturbing the life cycles of pathogens or modulating immunity. In this review, we focus on the development of broad-spectrum antiviral drugs that enhance the immune response. Some natural products present antiviral effects mediated by enhancing immunity, and their structures and mechanisms are summarized here. Natural products with immunomodulatory effects are also discussed, although their antiviral effects remain unknown. Given the power of immunity and the feasibility of host-directed therapy, we argue that both of these categories of natural products provide clues that may be beneficial for the discovery of broad-spectrum antiviral drugs.

How macrophages respond to two-dimensional materials: a critical overview focusing on toxicity

With wider use of graphene-based materials and other two-dimensional (2 D) materials in various fields, including electronics, composites, biomedicine, etc., 2 D materials can trigger undesired effects at cellular, tissue and organ level. Macrophages can be found in many organs. They are one of the most important cells in the immune system and they are relevant in the study of nanomaterials as they phagocytose them. Nanomaterials have multi-faceted effects on phagocytic immune cells like macrophages, showing signs of inflammation in the form of pro-inflammatory cytokine or reactive oxidation species production, or upregulation of activation markers due to the presence of these foreign bodies. This review is catered to researchers interested in the potential impact and toxicity of 2 D materials, particularly in macrophages, focusing on few-layer graphene, graphene oxide, graphene quantum dots, as well as other promising 2 D materials containing molybdenum, manganese, boron, phosphorus and tungsten. We describe applications relevant to the growing area of 2 D materials research, and the possible risks of ions and molecules used in the production of these promising 2 D materials, or those produced by the degradation and dissolution of 2 D materials.

Inhibitory Effects of Pectic Polysaccharide Isolated from Diospyros kaki Leaves on Tumor Cell Angiogenesis via VEGF and MMP-9 Regulation

Persimmon leaves are an attractive source of phytochemicals with potential health benefits. However, there are only a few reports on the chemical properties and biological activity of the polysaccharide fractions (PLE-I-III) of persimmon leaves. We evaluated the angiogenesis-inhibiting ability of pectic-polysaccharides. The molecular weight of PLEs was determined using a high-performance size-exclusion chromatography system. Tube formation assay of human umbilical vein endothelial cells (HUVECs) was performed using Matrigel-coated 96-well plates. Matrix metalloproteinase (MMP-9), vascular endothelial growth factor (VEGF), PI3K, Akt, and p38 phosphorylation levels were determined using Western blotting; VEGF and MMP-9 transcript levels were measured using SYBR Green qRT-PCR. PLE-I-III significantly inhibited HUVEC tube formation at 12.5 and 25 μg/mL. Among them, PLE-II showed the strongest anti-tube formation activity, and the mRNA/protein expression of angiogenesis-related factors (VEGF/MMP-9) was significantly reduced by PLE-II. PLE-II also suppressed the phosphorylation of PI3K/AKT and p38, JNK, and NF-κB p65 in HUVECs. These results suggest that the polysaccharide PLE-II isolated from persimmon leaves inhibited VEGF and MMP-9 expression in HUVECs via regulation of PI3K/AKT, p38, JNK, and NF-κB p65 signaling pathways.

Recent progress in polysaccharides from Panax ginseng C. A. Meyer

Panax ginseng C. A. Meyer (P. ginseng) has a long history of medicinal use and can treat a variety of diseases. P. ginseng contains a variety of active ingredients, such as saponins, polypeptides, volatile oils, and polysaccharides. Among them, saponins have always been considered as the main components responsible for its pharmacological activities. However, more and more studies have shown that polysaccharides play an indispensable role in the medicinal value of ginseng. Modern biological and medical studies have found that ginseng polysaccharides have complex structural characteristics and diverse biological activities, such as immune regulation, anti-tumor, antioxidant, hypoglycemic, and anti-radiation functions, among others. Additionally, the structural characteristics of ginseng polysaccharides are closely related to their activity. In this review, the research background, extraction, purification, structural characteristics, and biological activities of ginseng polysaccharides from different parts of P. ginseng (roots, flowers stems and leaves, and berries) under different growth conditions (artificially cultivated ginseng, mountain ginseng, and wild ginseng) are summarized. The structural characteristics of purified polysaccharides were reviewed. Meanwhile, their biological activities were introduced, and some possible mechanisms were listed. Furthermore, the structure-activity relationship of polysaccharides was discussed. Some research perspectives for the study of ginseng polysaccharides were also provided.

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.

Analysis of pectin from Panax ginseng flower buds and their binding activities to galectin-3

Water-soluble pectic polysaccharides isolated from Panax ginseng flower buds (WGFPA) were completely fractionated into six homogeneous fractions (WGFPA-1a, WGFPA-2a, WGFPA-3a, WGFPA-1b, WGFPA-2b and WGFPA-3b) by a combination of ion-exchange and size exclusion chromatographies. Monosaccharide composition, enzymatic hydrolysis and ¹³C nuclear magnetic resonance (NMR) spectra analysis were combined to characterize their structural features. Furthermore, the interactions between these polysaccharides and galectin-3 were evaluated by biolayer interferometry assay. The results showed that WGFPA-1a, WGFPA-2a and WGFPA-3a were rhamnogalacturonan I (RG-I) type pectin with abundant side chains, including α-L-1,5-arabinan, β-D-1,4-galactan, arabinogalactan I (AG-I) and arabinogalactan II (AG-II), exhibiting strong binding activities to galectin-3 with apparent KD values 4.9 μM, 0.71 μM and 0.24 μM, respectively. WGFPA-1b, WGFPA-2b and WGFPA-3b were homogalacturonan (HG) type pectin covalently linked with different ratios of rhamnogalacturonan II (RG-II) domains, showing weaker or no interactions with galectin-3. This study provides useful structural information for further investigation on the structure-activity relationship of ginseng flower buds pectin.

Preparing rhamnogalacturonan II domains from seven plant pectins using Penicillium oxalicum degradation and their structural comparison

Rhamnogalacturonan II (RG-II) is a complex pectin with diverse pharmaceutical activities. To assess how RG-II functions, the development of methods for its preparation is required. In this paper, pectin from Codonopsis pilosula was used to evaluate the ability of fungi and bacteria to degrade the pectin. We discovered that the fungus Penicillium oxalicum could efficiently lead to the recovery of RG-II domains by degrading the other pectic domains. Further, six pectin fractions from different medical plants were used as the sole carbon source for the growth of Penicillium oxalicum. The major polymeric products remaining after fungus degradation was RG-II domains. Depending of plant source, side chains A differed with respect to their proportion of L-Gal and L-Fuc and to their degree of methyletherification. Side chains B were made of 8-10 sugar residues and up to 2 acetyl groups. Overall, our method provides an effective way to prepare RG-II pectin domains for investigating their structure-function relationships.

Polysaccharides from ginseng leaves inhibit tumor metastasis via macrophage and NK cell activation

In this study, we purified the polysaccharide fraction (GS-P) from the leaves of Panax ginseng C.A. Meyer and analyzed its monosaccharide composition and antitumor and antimetastatic activity in vitro and in vivo. GS-P is a 10.2kDa pectic polysaccharide consisting of 15 different monosaccharides. GS-P treatment significantly inhibited metastasis in mice, in a dose-dependent manner. GS-P was not cytotoxic to colon 26-M3.1 cells and increased mouse splenocyte proliferation. Secretion of tumor necrosis factor (TNF)-α and interleukin (IL)-12 was enhanced in the peritoneal exudate macrophages (PEMs) of GS-P-treated mice. Moreover, PEMs obtained from GS-P-treated mice showed significantly higher tumoricidal activity against colon 26-M3.1 cells, and splenocytes from GS-P-treated mice significantly enhanced NK cell cytotoxicity against YAC-1 tumor cells. Pretreatment with anti-asialo GM1 (an antibody for NK cell depletion) partly suppressed the inhibitory effects of GS-P on lung metastasis. These data suggest that GS-P exhibits antimetastatic activity by promoting the activation of macrophages and NK cells.

Toll-like receptor 4-related immunostimulatory polysaccharides: Primary structure, activity relationships, and possible interaction models

Toll-like receptor (TLR) 4 is an important polysaccharide receptor; however, the relationships between the structures and biological activities of TLR4 and polysaccharides remain unknown. Many recent findings have revealed the primary structure of TLR4/MD-2-related polysaccharides, and several three-dimensional structure models of polysaccharide-binding proteins have been reported; and these models provide insights into the mechanisms through which polysaccharides interact with TLR4. In this review, we first discuss the origins of polysaccharides related to TLR4, including polysaccharides from higher plants, fungi, bacteria, algae, and animals. We then briefly describe the glucosidic bond types of TLR4-related heteroglycans and homoglycans and describe the typical molecular weights of TLR4-related polysaccharides. The primary structures and activity relationships of polysaccharides with TLR4/MD-2 are also discussed. Finally, based on the existing interaction models of LPS with TLR4/MD-2 and linear polysaccharides with proteins, we provide insights into the possible interaction models of polysaccharide ligands with TLR4/MD-2. To our knowledge, this review is the first to summarize the primary structures and activity relationships of TLR4-related polysaccharides and the possible mechanisms of interaction for TLR4 and TLR4-related polysaccharides.

Biotransformation of catechin and extraction of active polysaccharide from green tea leaves via simultaneous treatment with tannase and pectinase

BACKGROUND

Green tea is a dietary source of bioactive compounds for human health. Enzymatic treatments induce the bioconversion of bioactive components, which can improve biological activities. In this study, we investigated the effect of simultaneous treatment with tannase and Rapidase on biotransformation of catechins and extraction of polysaccharide from green tea extract (GTE).

RESULTS

Tannase and pectinase treatments induced the biotransformation of catechins and altered tea polysaccharide () content. The addition of GTE to the enzyme reaction resulted in a significant increase in degallated catechins, including gallic acid, a product of the tannase reaction (314.5-4076.0 µg mL(-1)) and a reduction in epigallocatechin gallate (EGCG). Biotransformation of catechins improved the radical scavenging activity of GTE. Pectinase treatment led to change of TPS composition in GTE by hydrolyzing polysaccharides. In addition, pectinase-driven hydrolysis in polysaccharides significantly increased TPS-induced Interleukin 6 (IL-6) production in macrophages. In particular, treatment of Rapidase (TPS-Ra) led to the highest IL-6 production among TPS samples, similar to treatment of highly purified pectinase (TPS-GTE), a positive control.

CONCLUSION

Simultaneous processing with tannase and Rapidase can be an efficient method for the extraction of bioactive polysaccharides and biotransformation of catechins with enhanced radical scavenging activity from green tea.

Chemical Composition, and Cytotoxic, Antioxidant and Antibacterial Activities of the Essential Oil from Ginseng Leaves

Panax ginseng C.A.Meyer is one of the most valuable traditional Chinese medicines. In this study, the essential oil of ginseng leaves (EOGL), collected using hydrodistillation and analyzed by GC/MS, contained a complex mixture of aliphatic (69.0%), terpenoid (21.5%) and aromatic compounds (2.4%). Among 54 components identified, the major ones were palmitic acid (36.1%), β-farnesene (15.4%), linoleic acid (9.8%) and phytol (5.6%). In the cytotoxicity study, EOGL exhibited obvious cytotoxic activities against different cancer cell lines, including Hela, A549, ZR-75-1, HT-29, SGC7901 and B16 cells. Furthermore, Annexin V-FITC/PI staining assay indicated that EOGL can induce late apoptosis of ZR-75-1 cells, and the percentage of apoptotic cells increased in a concentration-dependent manner (0.9% to 5.6% and 67.4%). In addition to this, we also found that EOGL exhibited weak DPPH radical scavenging (12.0 ± 0.4 mg/mL) and ABTS radical scavenging activities (1.6 ± 0.1 mg/mL), and showed antibacterial activity against the Gram-positive bacteria, Staphylococcus aureus and Bacillus subtilis, and the Gram-negative bacterium, Escherichia coli. The data suggest that EOGL, which possesses important biological activities, especially significant anticancer activity, could be a potential medicinal resource.

Rhamnogalacturonan II is a Toll-like receptor 4 agonist that inhibits tumor growth by activating dendritic cell-mediated CD8+ T cells

We evaluated the effectiveness of rhamnogalacturonan II (RG-II)-stimulated bone marrow-derived dendritic cells (BMDCs) vaccination on the induction of antitumor immunity in a mouse lymphoma model using EG7-lymphoma cells expressing ovalbumin (OVA). BMDCs treated with RG-II had an activated phenotype. RG-II induced interleukin (IL)-12, IL-1β, tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ) production during dendritic cell (DC) maturation. BMDCs stimulated with RG-II facilitate the proliferation of CD8⁺ T cells. Using BMDCs from the mice deficient in Toll-like receptors (TLRs), we revealed that RG-II activity is dependent on TLR4. RG-II showed a preventive effect of immunization with OVA-pulsed BMDCs against EG7 lymphoma. These results suggested that RG-II expedites the DC-based immune response through the TLR4 signaling pathway.

High molecular weight polysaccharides are key immunomodulators in North American ginseng extracts: characterization of the ginseng genetic signature in primary human immune cells

ETHNOPHARMACOLOGICAL RELEVANCE

Ginseng (GS) has played a pivotal role in traditional Chinese medicine for thousands of years. Its use has become increasingly popular in North America, in part due to the many claims of its immune-enhancing properties. The immunopharmacology of the North American variety of GS and its extracts is needed to substantiate these claims.

MATERIALS AND METHODS

Human peripheral blood mononuclear cells were exposed to different North American GS extracts and microarray analysis was performed. The profile of cytokine response to GS extracts was established by ELISA, and Ingenuity Pathway Analysis was used to identify potential signaling pathways responsible for the transcriptional profile induced by GS. Fractionation of the aqueous and polysaccharide extracts was done to determine the molecular weight of the active immune modulatory ingredient(s).

RESULTS

We found that GS induced a transcriptional profile of immunomodulation characterized by a net T(h)1 immune response, with up-regulation of multiple pro-inflammatory cytokines (e.g., IFN-γ, IL-23A and IL-6) and down-regulation of TGF-β, IL-13 and the LPS co-receptor CD14. Ingenuity Pathway Analysis (IPA) revealed that the MAPK (ERK-1/2), PI3K, p38 and NF-κB cascades were key signaling pathways through which GS may trigger its immunomodulatory action. Furthermore, induction of such an immunomodulatory signature was recapitulated with the high molecular weight polysaccharides found in aqueous and polysaccharide GS extracts.

CONCLUSIONS

Based on our results, we conclude that high molecular weight polysaccharides in North American GS aqueous and polysaccharide extracts likely trigger the MAPK (ERK-1/2), PI3K, p38 and NF-κB signaling pathways in PBMC resulting in the induction of a T(h)1 transcriptional profile. Our results may assist in optimizing GS-mediated immunomodulation and focus the search for compounds in GS extracts with specific immunomodulatory activities.

A placebo-controlled trial of Korean red ginseng extract for preventing influenza-like illness in healthy adults

Abstracts

Trial Registration

NCT01478009.

Beta-D-(1→4)-galactan-containing side chains in RG-I regions of pectic polysaccharides from Biophytum petersianum Klotzsch. contribute to expression of immunomodulating activity against intestinal Peyer's patch cells and macrophages

The aerial parts of the medicinal plant Biophytum petersianum have a long tradition for being used in Mali and other West-African countries against various ailments such as wound healing and malaria. Previous studies on polysaccharides from water extracts of the aerial parts showed the presence of pectic like polymers with an effect on the human complement system as well as the ability to activate macrophages and dendritic cells. The present study shows that pectic polysaccharide fragments (BPII.1 and BPII.2) as well as the original pectic polysaccharide (BPII) expressed immunomodulating activity against Peyer's patch immunocompetent cells. Exo-β-D-(1→3)-galactanase digestion succeeded to decrease IL-6 production enhancing activity against Peyer's patch cells of BPII.2, but the activity of BPII.1 did not decrease. Endo-β-D-(1→4)-galactanase digestion reduced the activities of both BPII.1 and BPII.2. BPII.1 and BPII.2 also stimulated IL-6 production enhancing activity against macrophages, and the activities of both pectic fragments were significantly decreased by either enzymic digestion with exo-β-D-(1→3)-galactanase or endo-β-D-(1→4)-galactanase. Trimming of terminal GlcA by exo-β-D-glucuronidase digestion did not affect IL-6 production enhancing activity against macrophages of both pectic fragments. Methylation analyses of endo-β-D-(1→4)-galactanase digestion products showed the characteristic decrement of 4-linked Gal residues in the pectic fragments. These results suggest that β-D-(1→4)-galactan-containing side chains in BPII.1 and BPII.2 play an important role for expression of immunomodulating activity against both Peyer's patch immunocompetent cells and macrophages in addition to β-D-(1→3,6)-galactan chains.

Matrix solid phase dispersion extraction of ginsenosides in the leaves of Panax ginseng C.M. Mey

The matrix solid phase dispersion (MSPD) was applied to the extraction of eight kinds of ginsenosides from the leaves of Panax ginseng C.M. Mey. The experimental conditions were examined and optimised. The extracts were analysed by high performance liquid chromatography (HPLC). When the diatomaceous earth was used as dispersant and 75% methanol was used as elution solvent, the highest extraction yields of the eight kinds of ginsenosides were obtained. For comparison, the reflux extraction was applied. The extraction yields obtained by the proposed method were comparable with those obtained by the reflux extraction. The proposed method is convenient, time-saving, and organic solvent minimising.

Efficacy and safety of a multiherbal formula with vitamin C and zinc (Immumax) in the management of the common cold

OBJECTIVE

To study the potential efficacy and tolerability of a natural multiherbal formula (Immumax) containing Echinacea extract 120 mg, garlic powder 100 mg, Nigella sativa oil 200 mg, and Panax ginseng extract 50 mg plus vitamin C 50 mg and elemental zinc 7.5 mg in the treatment of patients suffering from the common cold.

DESIGN AND SETTING

The study was conducted in a prospective, double-blind, randomized, controlled study design in an outpatient setting.

PATIENTS AND METHODS

Sixty-two eligible patients with symptoms of the common cold were randomized to either Immumax or placebo treatment groups for the duration of their symptoms or a maximum of 14 days. Resolution rates were estimated using Kaplan-Meier analysis, and resolution profiles were compared between groups using the log-rank test. The mean percentage change in total symptom severity scores at days 4 and 8 from baseline were compared between the two groups by one-way analysis of variance (ANOVA).

RESULTS

The median (interquartile range) time to resolution of all symptoms was 8 (5-9) days in the placebo group and 4 (3-6) days in the Immumax group. The results of the log-rank test indicate that symptoms resolved significantly faster in the Immumax group than in the placebo group (P < 0.001). The mean percentage reduction in total symptom severity scores from baseline at days 4 and 8 was significantly greater in the Immumax group than in the placebo group by one-way ANOVA (P < 0.01).

CONCLUSION

We can conclude from our study that Immumax is helpful in reducing the duration and severity of common cold symptoms.

Partial depolymerization of pectin by a photochemical reaction

Complex heterogeneous polysaccharides that comprise pectin were partially depolymerized by a photochemical reaction using ultraviolet light in the presence of titanium dioxide catalyst. In a period of 6h at pH 7, this UV/TiO(2) process decreased the average molecular weight of pectin from 400kDa to 200kDa. The characterization of the partially depolymerized pectin, which was fractionated by size-exclusion chromatography, was performed by (1)H NMR spectroscopy, and the spectra obtained showed that the resulting oligosaccharides and polysaccharides maintained the intact core structure of pectin. The monosaccharide content and depolymerization profile were determined by high-performance anion-exchange chromatography coupled with pulsed amperometric detection. This controlled photochemical depolymerization technique might be useful for preparation of pectin oligosaccharides as an ingredient in food and pharmaceutical products.

Pectic polysaccharides from Biophytum petersianum Klotzsch, and their activation of macrophages and dendritic cells

The Malian medicinal plant Biophytum petersianum Klotzsch (Oxalidaceae) is used as a treatment against various types of illnesses related to the immune system, such as joint pains, inflammations, fever, malaria, and wounds. A pectic polysaccharide obtained from a hot water extract of the aerial parts of B. petersianum has previously been reported to consist of arabinogalactans types I and II (AG-I and AG-II), probably linked to a rhamnogalacturonan backbone. We describe here further structural characteristics of the main polysaccharide fraction (BP1002) and fractions obtained by enzymatic degradations using endo-alpha-d-(1-->4)-polygalacturonase (BP1002-I to IV). The results indicate that in addition to previously reported structures, rhamnogalacturan type II and xylogalacturonan areas appear to be present in the pectic polymer isolated from the plant. Atomic force microscopy confirmed the presence of branched structures, as well as a polydisperse nature. We further tested whether the BP1002 main fraction or the enzymatically degraded products could induce immunomodulating activity through stimulation of subsets of leukocytes. We found that macrophages and dendritic cells were activated by BP1002 fractions, while there was little response of T cells, B cells, and NK cells. The enzymatic treatment of the BP1002 main fraction gave important information on the structure-activity relations. It seems that the presence of rhamnogalacturonan type I is important for the bioactivity, as the bioactivity decreases with the decreased amounts of rhamnose, galactose, and arabinose. The demonstration of bioactivity by the plant extracts might indicate the mechanisms behind the traditional medical use of the plant.

Pectin-like acidic polysaccharide from Panax ginseng with selective antiadhesive activity against pathogenic bacteria

Previous studies have revealed the inhibitory effects of an acidic polysaccharide purified from the root of Panax ginseng against the adhesion of Helicobacter pylori to gastric epithelial cells and the ability of Porphyromonas gingivalis to agglutinate erythrocytes. In this study, this acidic polysaccharide from P. ginseng, PG-F2, was investigated further, in order to characterize its antiadhesive effects against Actinobacillus actinomycetemcomitans, Propionibacterium acnes, and Staphylococcus aureus. The minimum inhibitory concentrations (MIC) were found to be in a range of 0.25-0.5mg/mL. However, results showed no inhibitory effects of PG-F2 against Lactobacillus acidophilus, Escherichia coli, or Staphylococcus epidermidis. PG-F2 is a pectin-type polysaccharide with a mean MW of 1.2 x 10(4) Da, and consists primarily of galacturonic and glucuronic acids along with rhamnose, arabinose, and galactose as minor components. The complete hydrolysis of PG-F2 via chemical or carbohydrolase enzyme treatment resulted in the abrogation of its antiadhesive activity, but limited hydrolysis via treatment with pectinase (EC. 3.2.1.15) yielded an oligosaccharide fraction, with activity comparable to the precursor PG-F2 (the MIC of ca. 0.01 mg/mL against H. pylori and P. gingivalis). Our results suggest that PG-F2 may exert a selective antiadhesive effect against pathogenic bacteria, while having no effects on beneficial and commensal bacteria.

Efficacy of an extract of North American ginseng containing poly-furanosyl-pyranosyl-saccharides for preventing upper respiratory tract infections: a randomized controlled trial

BACKGROUND

Upper respiratory tract infections are a major source of morbidity throughout the world. Extracts of the root of North American ginseng (Panax quinquefolium) have been found to have the potential to modulate both natural and acquired immune responses. We sought to examine the efficacy of an extract of North American ginseng root in preventing colds.

METHODS

We conducted a randomized, double-blind, placebo-controlled study at the onset of the influenza season. A total of 323 subjects 18-65 years of age with a history of at least 2 colds in the previous year were recruited from the general population in Edmonton, Alberta. The participants were instructed to take 2 capsules per day of either the North American ginseng extract or a placebo for a period of 4 months. The primary outcome measure was the number of Jackson-verified colds. Secondary variables measured included symptom severity, total number of days of symptoms and duration of all colds. Cold symptoms were scored by subjects using a 4-point scale.

RESULTS

Subjects who did not start treatment were excluded from the analysis (23 in the ginseng group and 21 in the placebo group), leaving 130 in the ginseng group and 149 in the placebo group. The mean number of colds per person was lower in the ginseng group than in the placebo group (0.68 [standard deviation (SD) 0.82] v. 0.93 [SD 0.91], difference 0.25%, 95% confidence interval [CI] 0.04-0.45). The proportion of subjects with 2 or more Jackson-verified colds during the 4-month period (10.0% v. 22.8%, 12.8% difference, 95% CI 4.3-21.3) was significantly lower in the ginseng group than in the placebo group, as were the total symptom score (77.5 [SD 84.6] v. 112.3 [SD 102.5], difference 1.5%, 95% CI 1.2-2.0) and the total number of days cold symptoms were reported (10.8 [SD 9.7] v. 16.5 [SD 13.8] days, difference 1.6%, 95% CI 1.3-2.0) for all colds.

INTERPRETATION

Ingestion of a poly-furanosyl-pyranosyl-saccharide-rich extract of the roots of North American ginseng in a moderate dose over 4 months reduced the mean number of colds per person, the proportion of subjects who experienced 2 or more colds, the severity of symptoms and the number of days cold symptoms were reported.

Botanical polysaccharides: macrophage immunomodulation and therapeutic potential

Botanical polysaccharides exhibit a number of beneficial therapeutic properties, and it is thought that the mechanisms involved in these effects are due to the modulation of innate immunity and, more specifically, macrophage function. In this review, we summarize our current state of understanding of the macrophage modulatory effects of botanical polysaccharides isolated from a wide array of different species of flora, including higher plants, mushrooms, lichens and algae. Overall, the primary effect of botanical polysaccharides is to enhance and/or activate macrophage immune responses, leading to immunomodulation, anti-tumor activity, wound-healing and other therapeutic effects. Furthermore, botanical and microbial polysaccharides bind to common surface receptors and induce similar immunomodulatory responses in macrophages, suggesting that evolutionarily conserved polysaccharide structural features are shared between these organisms. Thus, the evaluation of botanical polysaccharides provides a unique opportunity for the discovery of novel therapeutic agents and adjuvants that exhibit beneficial immunomodulatory properties.

Activating effect of Tanacetum vulgare L. pectin polysaccharide on ionic channels of neuronal membrane

The membranotropic effects of TVF tanacetan pectin polysaccharide derived from Tanacetum vulgare L. was studied by the voltage-clamp method on isolated neurons of Lymnaea stagnalis mollusk. TVF in concentrations of 0.1-10.0 microg/ml nonselectively activated the outward potassium and total inward (sodium and calcium) ionic currents (slightly dose-dependently and reversibly increased their amplitude by 5-10%) and decreased nonspecific leakage current.

A proprietary extract from North American ginseng (Panax quinquefolium) enhances IL-2 and IFN-gamma productions in murine spleen cells induced by Con-A

A patented aqueous extract from North American ginseng (Panax quinquefolium), containing mainly oligosaccharides and polysaccharides, is commercially available over the counter as COLD-FX (CVT-E002). This proprietary extract is used for the treatment of upper respiratory tract infections. Its in vitro stimulating effects on the immunoglobulin production by B lymphocytes and on natural immune responses by peritoneal exudates macrophages have been previously reported. Using C57 BL/6 mice, an ex vivo study was conducted to examine Con-A-induced splenocytic productions of interleukin-2 (IL-2) and interferon-gamma (IFN-gamma) as markers of acquired immune responses. CVT-E002 (10-500 microg/ml) significantly increased Con-A-induced IL-2 and IFN-gamma productions in spleen cells in a dose-dependent manner. Such response was seen by the ginseng extract originated from three different lots, suggesting consistency between the lots.

Immune cell stimulating activity of mucopolysaccharide isolated from yam (Dioscorea batatas)

Mucopolysaccharide (YMP) of yam (Dioscorea batatas Decne) was tested for immunomodulatory activity in vitro. We examined the effect of YMP on the viability, cell-mediated cytotoxicity and IFN-gamma secretion of splenic lymphocytes. The cytotoxic activity of mouse splenocyte against leukemia cell was increased in the presence of YMP (10 microg/ml). However, YMP (10 microg/ml) did not affect the viability of splenocytes. The production of IFN-gamma was significantly increased in the YMP treated splenocytes, suggesting that YMP may induce cell-mediated immune responses. The effects of YMP on phagocytic activity were studied in relation to uptaking capacity and lysosomal phosphatase activity of the mouse peritoneal macrophages in vitro. YMP (50 microg/ml) was found to increase uptaking capacity and lysosomal phosphatase activity of peritoneal macrophages. In addition, YMP (10-100 microg/ml) significantly increased the viability of peritoneal macrophages (P<0.05). The data obtained demonstrate that the YMP may be used as sources of immunoactive polysaccharides.

The three-dimensional structure of the mega-oligosaccharide rhamnogalacturonan II monomer: a combined molecular modeling and NMR investigation

In this study, we describe the first optimized molecular models of the mega-oligosaccharide rhamnogalaturonan II, that is found in the primary cell walls of all higher plants. The 750 MHz 1H NMR data previously reported and new heteronuclear correlation spectra (sensitivity-enhanced HSQC and HSQC-TOCSY) were first reassigned in light of the modifications in the primary structure. In turn, the experimental NMR data revealed the presence of an additional sugar, alpha-Araf (E-chain), and also the disaccharidic repeating unit of RG-I, another component of the pectic matrix. Due to a fuller picture of the primary structure of RG-II, a much more complete assignment of the NOE data has been achieved. A systematic computational study based on these NOEs lead us to a realistic three-dimensional description of the RG-II, in excellent agreement with the molecular dimensions obtained from various experimental methods.

A maize homologue of the bacterial CMP-3-deoxy-D-manno-2-octulosonate (KDO) synthetases. Similar pathways operate in plants and bacteria for the activation of KDO prior to its incorporation into outer cellular envelopes

The eight-carbon acid sugar 3-deoxy-d-manno-2-octulosonate (KDO) is an essential component of Gram-negative bacterial cell walls and capsular polysaccharides. KDO is incorporated into these polymers as CMP-KDO, which is produced in an unusual activation step catalyzed by the enzyme CMP-KDO synthetase. CMP-KDO synthetase activity has traditionally been considered exclusive to Gram-negative bacteria. CMP-KDO synthetase inhibitors attract great interest owing to their potential as selective bactericides. The sugar KDO is also a component of the rhamnogalacturonan II pectin fraction of the primary cell walls of most higher plants and of the cell wall polysaccharides of some green algae. However, the metabolic pathway leading to its incorporation into the plant cell wall is unknown. This paper describes the isolation and characterization of a maize gene, which codes for a protein very similar in sequence and activity to prokaryotic CMP-KDO synthetases. Remarkably, the maize gene can complement a CMP-KDO synthetase (kdsB) Salmonella typhimurium mutant defective in cell wall synthesis. ZmCKS activity is novel in eukaryotes. The evolutionary origin of ZmCKS is discussed in relation to the high degree of conservation between the plant and bacterial genes and its atypical codon usage in maize.

Structural characterization of the pectic polysaccharide rhamnogalacturonan II: evidence for the backbone location of the aceric acid-containing oligoglycosyl side chain

Monomeric rhamnogalacturonan II (mRG-II) was isolated from red wine and the reducing-end galacturonic acid of the backbone converted to L-galactonic acid by treatment with NaBH4. The resulting product (mRG-II'ol) was treated with a cell-free extract from Penicillium daleae, a fungus that has been shown to produce RG-II-fragmenting glycanases. The enzymatically generated products were fractionated by size-exclusion and anion-exchange chromatographies and the quantitatively major oligosaccharide fraction isolated. This fraction contained structurally related oligosaccharides that differed only in the presence or absence of a single Kdo residue. The Kdo residue was removed by acid hydrolysis and the resulting oligosaccharide then characterized by 1- and 2D 1H NMR spectroscopy, ESMS, and by glycosyl-residue and glycosyl-linkage composition analyses. The results of these analyses provide evidence for the presence of at least two structurally related oligosaccharides in the ratio approximately 6:1. The backbone of these oligosaccharides is composed of five (1-->4)-linked alpha-D-GalpA residues and a (1-->3)-linked L-galactonate. The (1-->4)-linked GalpA residue adjacent to the terminal non-reducing GalpA residue of the backbone is substituted at O-2 with an apiosyl-containing side chain. Beta3-L-Araf-(1-->5)-beta-D-DhapA is likely to be linked to O-3 of the GalpA residue at the non-reducing end of the backbone in the quantitatively major oligosaccharide and to O-3 of a (1-->4)-linked GalpA residue in the backbone of the minor oligosaccharide. Furthermore, the results of our studies have shown that the enzymically generated aceryl acid-containing oligosaccharide contains an alpha-linked aceryl acid residue and a beta-linked galactosyl residue. Thus, the anomeric linkages of these residues in RG-II should be revised.