Polysaccharides with complement fixing and macrophage stimulation activity from Opilia celtidifolia, isolation and partial characterisation

Structure-function relationships of pectic polysaccharides from broccoli by-products with in vitro B lymphocyte stimulatory activity

To study structure-function relationships of pectic polysaccharides with their immunostimulatory activity, broccoli by-products were used. Pectic polysaccharides composed by 64 mol% uronic acids, 18 mol% Ara, and 10 mol% Gal, obtained by hot water extraction, activated B lymphocytes in vitro (25-250 μg/mL). To disclose active structural features, combinations of ethanol and chromatographic fractionation and modification of the polysaccharides were performed. Polysaccharides insoluble in 80 % ethanol (Et80) showed higher immunostimulatory activity than the pristine mixture, which was independent of molecular weight range (12-400 kDa) and removal of terminal or short Ara side chains. Chemical sulfation did not promote B lymphocyte activation. However, the action of pectin methylesterase and endo-polygalacturonase on hot water extracted polysaccharides produced an acidic fraction with a high immunostimulatory activity. The de-esterified homogalacturonan region seem to be an important core to confer pectic polysaccharides immunostimulatory activity. Therefore, agri-food by-products are a source of pectic polysaccharide functional food ingredients.

Isolation, characterisation and complement fixation activity of acidic polysaccharides from Argemone mexicana used as antimalarials in Mali

CONTEXT

Global studies on Argemone mexicana L. (Papaveraceae) traditionally used against malaria in Mali are limited to its low-mass compounds activities, and little information on its bioactive polysaccharides is available.

OBJECTIVE

This study determines the structure and the immunomodulatory activity of polysaccharides from aerial parts of A. mexicana.

MATERIALS AND METHODS

Acidic polysaccharides from this plant material named HMAmA1 and HMAmA2 were isolated from water extracts. Their monosaccharide composition was determined by gas chromatography. Glycosidic linkages were determined using GC-MS. NMR was also applied. The polymers were tested for effects on the human complement system in vitro at different doses.

RESULTS

The monosaccharide composition showed that the two polysaccharides contained in different amounts the following monomers: arabinose, rhamnose, galactose, and galacturonic acid. Overall structural analysis showed the presence of a low ratio of 1,2-linked rhamnose compared to 1,4-linked galacturonic acid with arabinogalactans substituted on position 4 of rhamnose. NMR data showed the presence of galacturonans alternated by rhamnogalacturonans bearing arabinose and galactose units. α-Linkages were found for l-arabinose, l-rhamnose and d-galacturonic acid, while β-linkages were found for d-galactose. The two polysaccharides exhibited strong complement fixation activities, with HMAmA1 being the highest potent fraction. ICH₅₀ value of HMAmA1 was 5 µg/mL, compared to the control BPII being 15.9 µg/mL.

DISCUSSION AND CONCLUSIONS

Polysaccharides form A. mexicana presented a complement fixation effect. The complement system is an important part of the immune defense, and compounds acting on the cascade are of interest. Therefore, these polymers may be useful as immunodulatory agents.

Caucasian Dragonheads: Phenolic Compounds, Polysaccharides, and Bioactivity of Dracocephalum austriacum and Dracocephalum botryoides

Dracocephalum botryoides Steven and Dracocephalum austriacum L. are unexplored species of the Dracocephalum genus (Lamiaceae family) with a distribution in the Caucasus, where they are used in folk medicine and local cuisine. There are no data on the chemical composition of these Dracocephalum species. In this study, the application of a liquid chromatography-mass spectrometry technique for the metabolite profiling of methanol extracts from herbs and roots of D. austriacum and D. botryoides resulted in the identification of 50 compounds, including benzoic acid derivatives, phenylpropanoids, flavonoids and lignans. Water-soluble polysaccharides of the herbs and roots of D. austriacum and D. botryoides were isolated and characterized as mostly pectins with additive arabinogalactan-protein complexes and starch-like compounds. The antioxidant potential of the studied extracts of Dracocephalum and selected phenolics and water-soluble polysaccharides were investigated via radical-scavenging and ferrous (II) ion chelating assays. This paper demonstrates that herbs and roots of D. austriacum and D. botryoides are rich sources of metabolites and could be valuable plants for new biologically active products. To the best of our knowledge, this is the first study of whole plant metabolites and their antioxidant activity in D. austriacum and D. botryoides.

Seed coat mucilages: Structural, functional/bioactive properties, and genetic information

Seed coat mucilages are mainly polysaccharides covering the outer layer of the seeds to facilitate seed hydration and germination, thereby improving seedling emergence and reducing seedling mortality. Four types of polysaccharides are found in mucilages including xylan, pectin, glucomannan, and cellulose. Recently, mucilages from flaxseed, yellow mustard seed, chia seed, and so on, have been used extensively in the areas of food, pharmaceutical, and cosmetics contributing to stability, texture, and appearance. This review, for the first time, addresses the similarities and differences in physicochemical properties, molecular structure, and functional/bioactive properties of mucilages among different sources; highlights their structure and function relationships; and systematically summarizes the related genetic information, aiming with the intent to explore the potential functions thereby extending their future industrial applications.

Insight into anti-oxidative carbohydrate polymers from medicinal plants: Structure-activity relationships, mechanism of actions and interactions with bovine serum albumin

Recently, research associated with natural anti-oxidants leads to the chemical characterization of many compounds possessing strong anti-oxidant activity. Among these anti-oxidants, naturally occurring carbohydrate polymers containing pectic arabinogalactans esterified with phenolic acids in monomeric and dimeric forms are noteworthy. The presence of highly branched arabinogalactan type II side chains and sugar linked phenolic acid residues have been resolved as important parameters. The anti-oxidant activity of these compounds depend on their ability to convert free radicals into stable by-products and themselves oxidized to more stable and less reactive resonance stabilized radicals. Moreover, these carbohydrate polymers form water soluble stable complexes with protein. Such findings support their applications in a diversity of fields including food industry and pharmacy. This review highlights experimental evidences supporting that the carbohydrate polymers containing phenolic polysaccharides may become promising drug candidate for the prevention of aging and age related diseases.

Adjuvant activity of PCP-II, a polysaccharide from Poria cocos, on a whole killed rabies vaccine

Adjuvants are important components of vaccination strategies because they boost and accelerate the immune response. The aim of this study was to investigate the adjuvant activity of PCP-II, a polysaccharide isolated from Poria cocos, together with an inactivated rabies vaccine. The polysaccharide PCP-II was compared with the common veterinary rabies vaccine adjuvant Alhydrogel by co-administration of either adjuvant with the inactivated rabies virus rCVS-11-G to mice via the intramuscular route. Blood samples were collected to determine the virus-neutralizing antibody (VNA) titer and assess activation of B and T lymphocytes. Inguinal lymph node samples were collected, and proliferation of B lymphocytes was measured. Splenocytes were isolated, and antigen-specific cellular immune responses were evaluated by enzyme-linked immunospot and immunosorbent assays (ELISpot assay and ELISA, respectively). The results showed that PCP-II enhanced and promoted an increase in the VNA titer in the mice compared to Alhydrogel. Flow cytometry assays revealed that the polysaccharide activated more B lymphocytes in the lymph nodes and more B and T lymphocytes in the blood. Assessment of antigen-specific cellular immune responses showed that PCP-II strongly induced T lymphocyte proliferation in the spleen and high levels of cytokine secretion from splenocytes. All of these data suggest that PCP-II possesses excellent adjuvant activity and enhances both cellular and humoral immunity in mice. After examining the adjuvant activities of PCP-II in mice, dogs were immunized with rCVS-11-G together with Alhydrogel or PCP-II as an adjuvant; the control group was injected with a commercial rabies vaccine. Serum samples were collected, and the VNA titers were measured. PCP-II caused increases in the VNA titers in both the booster and single-dose immunization tests when co-administered with rCVS-11-G compared with Alhydrogel. The VNA titer of the commercial vaccine group was also significantly lower than that of the PCP-II group. These data indicate that PCP-II is an excellent candidate adjuvant for inactive rabies vaccines in the veterinary setting.

Antioxidant, immunomodulatory, oxidative stress inhibitory and iron supplementation effect of Astragalus membranaceus polysaccharide-iron (III) complex on iron-deficiency anemia mouse model

As iron supplement, the antioxidant activities of APS-iron (III) complex were comprehensively evaluated by 5-axe cobweb charts, which indicated the APS-iron (III) complex had a certain antioxidant activity and been weaker than that of APS. The results of immunological activity experiments indicated the stimulation index increased with APS-iron (III) complex concentration increase. When the concentration of the APS-iron (III) complex was 50 μg/mL, the lymphocytes proliferation increased by 35.7% compared with APS. APS-iron (III) complex also had better complement fixing activity than APS, 0.589 mg/mL of which achieved 50% complement fixing activities. Through the iron supplement experiments on iron-deficiency anemia mouse model, we found the APS-iron (III) complex faster increased hemoglobin concentration, SOD, CAT and faster decreased MDA to the normal level than Niferex and ferrous sulfate. Histological results revealed that the tissue sections were clear without obvious pathological changes and bone marrow had most hematopoietic cells from APS-iron (III) complex rat group, which also proved the APS-iron (III) complex had no significant side effects. Therefore, APS-iron (III) complex may be developed as a multifunctional iron supplement for clinical application.

Polysaccharides from chayote enhance lipid efflux and regulate NLRP3 inflammasome priming in macrophage-like THP-1 cells exposed to cholesterol crystals

The contribution of dietary fiber to decrease the risk of atherosclerosis may occur through other mechanisms besides the increased excretion of cholesterol. Although macrophages are crucial for lipid clearance, the excessive uptake of cholesterol crystals (CC) by these cells induce NLRP3 inflammasome and foam cell formation. Thus, we investigated whether the water-soluble DF from chayote (WSP) regulate CC-pretreated macrophage-like THP-1 cells. Linkage analysis indicated that WSP is composed mainly of pectic homogalacturonan and highly branched type I rhamnogalacturonan as well as hemicellulosic material including glucomannan, xyloglucan, and glucurono(arabino)xylan. WSP reduced interleukin (IL)-1β and chemokine release in CC-pretreated macrophages. Notably, WSP also reduced lipid accumulation in cells previously exposed to CC. Furthermore, WSP upregulated liver X receptor alpha expression, which may account for increased lipid efflux, and reduced matrix metallopeptidase 9 expression. WSP also reduced active caspase-1 protein levels, and downregulated NLRP3 and IL-1β gene expression in CC-pretreated cells, suggesting that this polysaccharide fraction regulates the priming signals required for NLRP3 inflammasome activation. Thus, WSP regulate lipid efflux and suppress inflammasome priming in macrophages, suggesting that the health benefits of this dietary fiber could go beyond its physical properties on the gastrointestinal tract.

Two complement fixing pectic polysaccharides from pedicel of Lycium barbarum L. promote cellular antioxidant defense

Purification, characterization and biological activities of polysaccharides from Lycium barbarum pedicel were investigated in this study. Two polysaccharides, PLBP-I-I and PLBP-II-I, were obtained from water extracts by anion exchange chromatography and gel filtration. Structural elucidation based on IR, ¹H NMR, and ¹³C NMR spectra indicated that these two fractions were typical pectic polysaccharides, with homogalacturonan and rhamnogalacturonan type I regions and arabinogalactan side chains, and some of the galacturonic acid units were methyl esterified. Both fractions exhibited potent complement fixating activity and pro-antioxidant defense capacity, and those two fractions showed different activities. The higher complement fixation activity was obtained in fraction PLBP-I-I, while the higher pro-antioxidant defense capacity was obtained in fraction PLBP-II-I, which may be due to the structural differences between those two fractions. Thus, the pedicel of L. barbarum could be used as a potential source for natural immunomodulator and antioxidant.

Effect of Low Temperature Cultivation on the Phytochemical Profile and Bioactivity of Arctic Plants: A Case of Dracocephalum palmatum

The influence of climatic factors, e.g., low temperature, on the phytochemical composition and bioactivity of the arctic plant Dracocephalum palmatum Steph. ax Willd. (palmate dragonhead), a traditional food and medical herb of Northern Siberia, was investigated. D. palmatum seedlings were grown in a greenhouse experiment at normal (20 °C, NT) and low (1 °C, LT) temperature levels and five groups of components that were lipophilic and hydrophilic in nature were characterized. The analyses indicated that D. palmatum under NT demonstrates high content of photosynthetic pigments, specific fatty acid (FA) profile with domination of saturated FA (53.3%) and the essential oil with trans-pinocamphone as a main component (37.9%). Phenolic compounds were identified using a combination of high performance liquid chromatography with diode array detection and electrospray ionization mass-spectrometric detection (HPLC-DAD-ESI-MS) techniques, as well as free carbohydrates and water soluble polysaccharides. For the first time, it was established that the cold acclimation of D. palmatum seedlings resulted in various changes in physiological and biochemical parameters such as membrane permeability, photosynthetic potential, membrane fluidity, leaf surface secretory function, reactive oxygen species-antioxidant balance, osmoregulator content and cell wall polymers. In brief, results showed that the adaptive strategy of D. palmatum under LT was realized on the accumulation of membrane or surface components with more fluid properties (unsaturated FA and essential oils), antioxidants (phenolic compounds and enzymes), osmoprotectants (free sugars) and cell wall components (polysaccharides). In addition, the occurrence of unusual flavonoids including two new isomeric malonyl esters of eriodictyol-7-O-glucoside was found in LT samples. Data thus obtained allow improving our understanding of ecophysiological mechanisms of cold adaptation of arctic plants.

Arabinogalactan Proteins From Baobab and Acacia Seeds Influence Innate Immunity of Human Keratinocytes In Vitro

Plant derived arabinogalactan proteins (AGP) were repeatedly confirmed as immunologically as well as dermatologically active compounds. However, little is currently known regarding their potential activity toward skin innate immunity. Here, we extracted and purified AGP from acacia (Acacia senegal) and baobab (Adansonia digitata) seeds to investigate their biological effects on the HaCaT keratinocyte cell line in an in vitro system. While AGP from both sources did not exhibit any cytotoxic effect, AGP from acacia seeds enhanced cell viability. Moreover, real-time quantitative reverse transcription-polymerase chain reaction (qRT-PCR) analysis showed that AGP extracted from both species induced a substantial overexpression of hBD-2, TLR-5, and IL1-α genes. These data suggest that plant AGP, already known to control plant defensive processes, could also modulate skin innate immune responses. J. Cell. Physiol. 232: 2558-2568, 2017. © 2016 Wiley Periodicals, Inc.

Meadowsweet Teas as New Functional Beverages: Comparative Analysis of Nutrients, Phytochemicals and Biological Effects of Four Filipendula Species

In recent years, the increased popularity of functional beverages such as herbal teas and decoctions has led to the search for new sources of raw materials that provide appropriate taste and functionality to consumers. The objective of this study was to investigate the nutritional, phytochemical profiles and bioactivities of possible functional beverages produced from F. ulmaria and its alternative substitutes (F. camtschatica, F. denudata, F. stepposa). The investigated decoctions were analyzed regarding their macronutrient, carbohydrate, organic acid, amino acid and mineral composition. Quantification of the main phenolic compounds in the decoctions of meadowsweet floral teas was performed by a microcolumn RP-HPLC-UV procedure; the highest content was revealed in F. stepposa tea. The investigation of the essential oil of four meadowsweet teas revealed the presence of 28 compounds, including simple phenols, monoterpenes, sesquiterpenes and aliphatic components. The dominance of methyl salicylate and salicylaldehyde was noted in all samples. Studies on the water soluble polysaccharides of Filipendula flowers allowed us to establish their general affiliation to galactans and/or arabinogalactans with an admixture of glucans of the starch type and galacturonans as minor components. The bioactivity data demonstrated a good ability of meadowsweet teas to inhibit amylase, α-glucosidase and AGE formation. Tea samples showed antioxidant properties by the DPPH•, ABTS•+ and Br• free radicals scavenging assays and the carotene bleaching assay, caused by the presence of highly active ellagitannins. The anti-complement activity of the water-soluble polysaccharide fraction of meadowsweet teas indicated their possible immune-modulating properties. Filipendula beverage formulations can be expected to deliver beneficial effects due to their unique nutritional and phytochemical profiles. Potential applications as health-promoting functional products may be suggested.

Arabinoxylan from Mucilage of Tomatoes (Solanum lycopersicum L.): Structure and Antinociceptive Effect in Mouse Models

Tomato is a known functional food due to its content of bioactive compounds. Herein, polysaccharides were extracted from mucilage of tomatoes, and a purified fraction (PTOK) was analyzed by sugar composition, methylation, and NMR spectroscopy analysis. The results showed the presence of an arabinoxylan, having (1→4)-linked β-d-Xylp units in the main chain, which carried a low proportion of branching (∼5.6%), at O-2 and O-3 position, with side chains constituted by single Araf or Xylp units. Intraperitoneal administration of the arabinoxylan in mice significantly reduced the number of abdominal constrictions induced by 0.6% acetic acid and the inflammatory phase of nociception induced by 2.5% formalin, indicating that it had an antinociceptive effect on inflammatory pain models, amplifying the biological role displayed by arabinoxylans in the diet. Furthermore, this study reports the presence of an arabinoxylan in a dicotyledon plant, and also it is the first study of polysaccharides from mucilage of tomatoes.

Medicinal plants from Mali: Chemistry and biology

ETHNOPHARMACOLOGICAL RELEVANCE

Mali is one of the countries in West Africa where the health system rely the most on traditional medicine. The healers are mainly using medicinal plants for their treatments. The studies performed being the basis for this review is of importance as they will contribute to sustaining the traditional knowledge. They contribute to evaluate and improve locally produced herbal remedies, and the review gives also an overview of the plant preparations that will have the most potential to be evaluated for new Improved Traditional Medicines.

AIM OF THE REVIEW

The aim of this review is to give an overview of the studies performed related to medicinal plants from Mali in the period 1995-2015. These studies include ethnopharmacology, chemistry and biological studies of the plants that were chosen based on our interviews with the healers in different regions of Mali, and contribute to sustainable knowledge on the medicinal plants. The Department of Traditional Medicine, Bamako, Mali, is responsible for registering the knowledge of the traditional healers on their use of medicinal plants and also identifying compounds in the plants responsible for the bioactivities claimed. The studies reported aimed at getting information from the healers on the use of medicinal plants, and study the biology and chemistry of selected plants for the purpose of verifying the traditional use of the plants. These studies should form the basis for necessary knowledge for the development of registered Improved Traditional Medicines in Mali.

MATERIALS AND METHODS

The healers were the ethnopharmacological informants. Questions asked initially were related to wound healing. This was because the immune system is involved when wounds are healed, and additionally the immune system is involved in the majority of the illnesses common in Mali. Based on the results of the interviews the plant material for studies was selected. Studies were performed on the plant parts the healers were using when treating their patients. Conventional chromatographic and spectroscopic methods were used for the isolation and structural elucidation of compounds. The compounds to study were selected based on the bioassays performed concomitant with the fractionation.

RESULTS

Our results show that plants traditionally used as wound healing agents contain polysaccharides basically of pectin nature with immunomodulating activities. These pectins all have different and new structures. Several of the plants also contain compounds with effects related to antioxidant properties. These compounds are mainly of polyphenolic nature. Three of these are new compounds from Nature, while 32 was for the first time described from the plant they were isolated from. This review gives an overview of the most important results obtained during the 20 year long collaboration between Department of Traditional Medicine, Bamako, Mali, and Department of Pharmacognosy, School of Pharmacy, University of Oslo, Norway.

CONCLUSION

Our studies showed that ethnopharmacological information is important for the determination of screening and chemical methods to be used for studies of plants used in traditional medicine.

Antioxidant and immunomodulatory properties of polysaccharides from Allanblackia floribunda Oliv stem bark and Chromolaena odorata (L.) King and H.E. Robins leaves

BACKGROUND

Many plant polysaccharides have shown high antioxidant and immunostimulating properties and can be explored as novel molecules with biological properties that can potentially improve immune function. The objective of this work was to characterize soluble and cell wall polysaccharides isolated from the stem bark of Allanblackia floribunda and Chromolaena odorata leaves and to evaluate their antioxidant and immunomodulatory properties.

METHODS

Three polysaccharide fractions: soluble polysaccharides (PoS), pectins (Pec) and hemicelluloses (Hem) were extracted from A. floribunda stem bark and C. odorata leaves. These samples were analysed for their proteins, phenolic compounds and total sugar contents. The monosaccharide composition was determined by gas chromatography and arabinogalactan proteins content in PoS was evaluated by rocket electrophoresis. The in vitro antioxidant activities were evaluated by 1, 1-diphenyl-2-picryl hydrazyl (DPPH) and 2,2'-azino-bis-3-éthylbenzylthiazoline-6-sulphonic acid (ABTS) radical scavenging assays and ferrous ions chelating activity. Immunomodulatory activities were performed on the peripheral blood mononuclear cells (PBMCs) using proliferation and enzyme linked immunospot (ELISPOT) method to determine the production of an interferon-gamma.

RESULTS

The characterization of the various fractions showed varied metabolites in each plant. In PoS fractions, Ara and Gal were the major monosaccharides found, indicating that arabinogalactans are the primary macromolecules. Hem fractions contained predominantly Xyl and GalA for A. floribunda and Xyl (upto 80 %) for and C. odorata. A. floribunda Hem fraction and C. odorata PoS fraction showed significant DPPH and ABTS radical scavenging activities and immunostimulatory activity via stimulation of PBMC and production of IFN-γ in a dose-dependent manner.

CONCLUSION

The results obtained from this study support the ethnomedicinal use of the stem bark of A. floribunda and leaves of C. odorata. Further research is necessary to have supporting evidence that the antioxidative and immunomodulative activities of these fractions are really connected to the polysaccharides and not polyphenols.

Bitter Gentian Teas: Nutritional and Phytochemical Profiles, Polysaccharide Characterisation and Bioactivity

As a result of the wide distribution of herbal teas the data on nutritional characterisation, chemical profile and biological activity of these products are required. The decoctions of Gentiana algida, G. decumbens, G. macrophylla and G. triflora herb teas were nutritionally characterized with respect to their macronutrients, demonstrating the predominance of polysaccharides and low lipid content. Gentian decoctions were also submitted to a microcolumn RP-HPLC-UV analysis of phytochemicals demonstrating a high content of iridoids (177.18-641.04 μg/mL) and flavonoids (89.15-405.71 μg/mL). Additionally, mangiferin was detected in samples of G. triflora tea (19.89 μg/mL). Five free sugars (fructose, glucose, sucrose, gentiobiose, gentianose) were identified in all gentian teas studied, as well as six organic acids (malic, citric, tartaric, oxalic, succinic, quinic). Pectic polysaccharides with a high content of rhamnogalacturonans and arabinogalactans were also identified and characterized in gentian decoctions for the first time. Gentian tea decoctions and their specific compounds (gentiopicroside, loganic acid-6'-O-β-d-glucoside, isoorientin, isoorientin-4'-O-β-d-glucoside, mangiferin, water-soluble polysaccharides) showed a promising antimicrobial, anti-inflammatory and antioxidant potentials. Evidences obtained indicate the prospective use of gentian herb teas as food products and medicines.

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.

Macrophage activation by polysaccharides from Atractylodes macrocephala Koidz through the nuclear factor-κB pathway

CONTEXT

Atractylodes macrocephala Koidz is a traditional herb. Atractylodes macrocephalaon polysaccharides (AMP) have been found to enhance immunity and improve heart function. However, the mechanisms of the immunomodulatory effect have not been investigated.

OBJECTIVE

We examined whether AMP activated macrophages and explored the mechanisms of activation.

MATERIALS AND METHODS

AMP was prepared and evaluated its immunomodulatory activity (25, 50, 100, and 200 μg/mL) by detecting the phagocytosis and the production of tumor necrosis factor-α (TNF-α), IFN-γ, and nitric oxide (NO) in RAW264.7 macrophages. Furthermore, the role of nuclear factor-κB (NF-κB) pathway was examined in regulating TNF-α and NO production.

RESULTS

The phagocytosis of macrophages was enhanced by AMP in a dose-dependent manner and the maximal phagocytosis of macrophages occurred at concentrations of 100 and 200 μg/mL. NO, TNF-α, and IFN-γ release was also found to be dose dependent by increasing concentrations of AMP and reached the peak at a concentration of 200 μg/mL. In addition, AMP induced inhibitor kappaB (IκB) degradation and the activation of NF-κB by p65 nuclear translocation, and then the activation of NF-κB in nucleus peaked at a concentration of 200 μg/mL. Besides, NF-κB-specific inhibitor pyrrolidine dithiocarbamate (PDTC) decreased AMP-induced NO and TNF-α production.

DISCUSSION AND CONCLUSION

These data suggest that AMP may modulate macrophage activities by stimulating NF-κB or activating NF-κB-dependent mechanisms.

Complement activity of polysaccharides from three different plant parts of Terminalia macroptera extracted as healers do

ETHNOPHARMACOLOGICAL RELEVANCE

Water decoctions of the root bark, stem bark and leaves of Terminalia macroptera are used by traditional healers in Mali to cure a wide range of illnesses, such as wounds, hepatitis, malaria, fever, cough and diarrhea as well as tuberculosis. Plant polysaccharides isolated from crude water extracts have previously shown effects related to the immune system. The aims of this study are comparing the properties of the polysaccharides among different plant parts, as well as relationship between chemical characteristics and complement fixation activities when the plant material has been extracted as the traditional healers do, with boiling water directly.

MATERIALS AND METHODS

Root bark, stem bark and leaves of Terminalia macroptera were extracted by boiling water, and five purified polysaccharide fractions were obtained by anion exchange chromatography and gel filtration. Chemical compositions were determined by GC of the TMS derivatives of the methyl-glycosides and the linkage determined after permethylation and GC-MS of the derived partly methylated alditol acetates. The bioactivity was determined by the complement fixation assay of the crude extracts and purified fractions.

RESULTS

The acidic fraction TRBD-I-I isolated from the root bark was the most active of the fractions isolated. Structural studies showed that all purified fractions are of pectic nature, containing rhamnogalacturonan type I backbone. Arabinogalactan type II side chains were present in all fractions except TRBD-I-II. The observed differences in complement fixation activities among the five purified polysaccharide fractions are probably due to differences in monosaccharide compositions, linkage types and molecular sizes.

CONCLUSION

The crude extracts from root bark and stem bark have similar total activities, both higher than those from leaves. The root bark, leaves and stem bark are all good sources for fractions containing bioactive polysaccharides. But due to sustainability, it is prefer to use leaves rather than the other two plant parts, and then the dosage by weight must be higher when using leaves.

Complement fixing polysaccharides from Terminalia macroptera root bark, stem bark and leaves

The root bark, stem bark and leaves of Terminalia macroptera were sequentially extracted with ethanol, 50% ethanol-water, and 50 °C and 100 °C water using an accelerated solvent extractor. Ten bioactive purified polysaccharide fractions were obtained from those crude extracts after anion exchange chromatography and gel filtration. The polysaccharides and their native extracts were characterized with respect to molecular weight, chemical compositions and effects in the complement assay. The chemical compositions showed that the polysaccharides are of pectic nature. The results indicated that there was no great difference of the complement fixation activities in the crude extracts from the different plant parts when extracting with the accelerated solvent extraction system. The purified polysaccharide fractions 100WTSBH-I-I and 100WTRBH-I-I isolated from the 100 °C water extracts of stem and root bark respectively, showed the highest complement fixation activities. These two fractions have rhamnogalacturonan type I backbone, but only 100WTSBH-I-I contains side chains of both arabinogalactan type I and II. Based on the yield and activities of the fractions studied those from the root bark gave highest results, followed by those from leaves and stem bark. But in total, all plant materials are good sources for fractions containing bioactive polysaccharides.

Immunomodulating polysaccharides from Lessertia frutescens leaves: isolation, characterization and structure activity relationship

ETHNOPHARMACOLOGICAL RELEVANCE

Sutherlandia frutescens (syn. Lessertia frutescens) is an indigenous plant in Southern Africa and has been extensively studied from the ethnobotanical point of view. Amongst the various traditional uses, several illnesses involving the immune system have been reported. Due to some of the therapeutic effects observed, in relation to the traditional uses reported by the "khoi san" and "nama" people on cancer related illnesses, the plant has been given the local name kankerbos (cancerbush). Recently the plant has also been used amongst HIV/AIDS patients to stimulate the immune system.

MATERIALS AND METHODS

Leaves of Sutherlandia frutescens were extracted sequentially with ethanol, 50% ethanol/water, and water at 50 and 100°C. The polysaccharides were extracted with water and fractionated by ion exchange chromatography and gel filtration to obtain enriched polysaccharide fractions. The bioactivities of the fractions were tested in the complement assay. Some of the fractions were treated with the enzyme pectinase, and the fragments thus produced were separated by gel filtration and their activities tested. Monosaccharide compositions and linkage analyses were determined for the relevant fractions.

RESULTS

The leaves of Sutherlandia frutescens contain polysaccharides of the pectin type. Fractions from both the water extracts of 50 and 100°C were bioactive. Fractions chosen for further studies showed that the fragment with the highest M(W) after the pectinase treatment had a substantially higher biological effect than the parent molecules. Based on a comparison of the different fractions it was concluded that galactose-rich regions were important for the bioactivity, these being of the AGII and AGI type, with the latter probably being more important than the former. Fragments rich in xylose also gave higher activity than those without it.

CONCLUSIONS

Our theory that the polysaccharides present in the leaves of Sutherlandia frutescens could be of importance as immunomodulating agents was confirmed. It was also shown that certain types of polysaccharides had a higher effect in the complement system than others. Thus both the water extracts obtained at 50 and 100°C contain interesting biologically active polysaccharides.

Effects of pectic polysaccharides isolated from leek on the production of reactive oxygen and nitrogen species by phagocytes

The current survey investigates the effect of four polysaccharides isolated from fresh leek or alcohol insoluble substances (AIS) of leek on the production of reactive oxygen species (ROS) and reactive nitrogen species (RNS) from phagocytes. The ability of the polysaccharides to activate serum complement was also investigated. Despite the lack of antioxidant activity, the pectic polysaccharides significantly decreased the production of ROS by human neutrophils. Polysaccharides isolated from AIS markedly activated RAW 264.7 macrophages for RNS production in a concentration-dependent manner. The Western blot analysis revealed that this effect was due to the stimulation of the inducible nitric oxide synthase protein expression of macrophages. The polysaccharides extracted from AIS with water showed the ability to fix serum complement, especially through the alternative pathway. It was found that the polysaccharide that has the highest complement-fixing effect is characterized by the highest content of uronic acids and the highest molecular weight.

Influence of polysaccharide fractions isolated from Caltha palustris L. on the cellular immune response in collagen-induced arthritis (CIA) in mice. A comparison with methotrexate

ETHNOPHARMACOLOGICAL RELEVANCE

The extracts from Caltha palustris have been used in traditional Canadian and Asian medicine to treat arthritis and rheumatism.

AIMS

The aim of the study was to investigate the anti-arthritis and immunomodulatory activity of the polysaccharide fractions B and C of Caltha palustris L. herbal extracts in collagen-induced arthritis (CIA) mice, an animal model of rheumathoid arthritis. The results were compared with those of methotrexate (MTX) treatment.

MATERIALS AND METHODS

CIA was induced in male and female DBA/1J mice by intradermal injection of chicken type II collagen in Freund's complete adjuvant (cFA). Booster injection of collagen (in incomplete Freund's adjuvant) was given on day 21 of the experiment. Mice were treated daily for 21 consecutive days with investigated fractions B or C at a dose of 10mg/kg (the first dose was given 24h after the booster) or phosphate buffered saline (PBS) (negative and positive control group). MTX was administered in parallel, intraperitoneally at three weekly cycles-every 48 h for 3 weeks at a dose of 6.6 mg/kg, the first dose was given on day 22 of the experiment. The severity of arthritis was evaluated by arthritic scores. Flow cytometry was used to investigate subsets of T lymphocytes in the thymus, and T and B lymphocytes in the spleen, and in mesenteric lymph nodes. T regulatory lymphocytes in the spleen were also quantified by means of flow cytometry. The levels of IL-2, IL-6, IL-10, IFN-γ and TNF-α in serum were also measured.

RESULTS

The results revealed that fraction B significantly reduced the severity of joint swelling and erythema to a similar degree as MTX. It was also found that B fraction and MTX inhibited leucocytosis in peripheral blood caused by CIA, however the inhibitory effect of MTX persisted longer than that of fraction B. The analysis of lymphocyte T subsets demonstrated that both investigated fractions and MTX caused a partial or complete normalization in the percentage and the absolute number of CD4(-)CD8(-) thymocytes (immature, double-negative cells), and increased the percentage of CD8(+) T cells in peripheral lymphoid organs of mice with CIA. Moreover, an increase in the percentage of CD4(+) thymic cells was observed after treatment with fraction B or MTX. Fraction C showed the weakest effect in normalization of the percentage and the absolute number of CD4(-)CD8(-) thymus lymphocytes in mice with CIA. The potency of fraction B was comparable to MTX. A significant decrease in the percentage and the absolute count of splenic T-regulatory cells (CD4(+)CD25(+)FOXP3(+)) was observed after treatment with both Caltha palustris fractions. The inhibiting influence of investigated fractions on TNF-α serum concentration was significant and lasted longer in the case of fraction C. Production of other cytokines was modulated slightly (increase in IFN-γ) or markedly (decrease in IL-2).

CONCLUSION

The results of the experiment suggested that the administration of polysaccharide B fraction from Caltha palustris extract significantly suppressed the progression of CIA. These results are similar to those obtained in the case of MTX treatment. This indicates that fraction B may be a potent candidate for botanical anti-arthritic agent.

Complement activation and inhibition in wound healing

Complement activation is needed to restore tissue injury; however, inappropriate activation of complement, as seen in chronic wounds can cause cell death and enhance inflammation, thus contributing to further injury and impaired wound healing. Therefore, attenuation of complement activation by specific inhibitors is considered as an innovative wound care strategy. Currently, the effects of several complement inhibitors, for example, the C3 inhibitor compstatin and several C1 and C5 inhibitors, are under investigation in patients with complement-mediated diseases. Although (pre)clinical research into the effects of these complement inhibitors on wound healing is limited, available data indicate that reduction of complement activation can improve wound healing. Moreover, medicine may take advantage of safe and effective agents that are produced by various microorganisms, symbionts, for example, medicinal maggots, and plants to attenuate complement activation. To conclude, for the development of new wound care strategies, (pre)clinical studies into the roles of complement and the effects of application of complement inhibitors in wound healing are required.

Anticancer and Immunopotentiating Activities of Crude Polysaccharides from Pleurotus nebrodensis on Mouse Sarcoma 180

Pleurotus nebrodensis is an edible and commercially available mushroom in Korea. This study was conducted in order to evaluate the anticancer and immunopotentiating activities of crude polysaccharides, extracted in methanol, neutral saline, and hot water (hereafter referred to as Fr. MeOH, Fr. NaCl, and Fr. HW, respectively) from the fruiting bodies of P. nebrodensis. β-Glucan and protein contents in Fr. MeOH, Fr. NaCl, and Fr. HW extracts of P. nebrodensis ranged from 23.79~36.63 g/100 g and 4.45~6.12 g/100 g, respectively. Crude polysaccharides were not cytotoxic against sarcoma 180, HT-29, NIH3T3, and RAW 264.7 cell lines at a range of 10~2,000 µg/mL. Intraperitoneal injection with crude polysaccharides resulted in a life prolongation effect of 11.76~27.06% in mice previously inoculated with sarcoma 180. Treatment with Fr. NaCl resulted in an increase in the numbers of spleen cells by 1.49 fold at the concentration of 50 µg/mL, compared with control. Fr. HW improved the immuno-potentiating activity of B lymphocytes through an increase in alkaline phosphatase activity by 1.65 fold, compared with control at 200 µg/mL. Maximum production of nitric oxide (14.3 µM) was recorded in the Fr. NaCl fraction at 200 µg/mL. Production of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6) was significantly higher, compared to control, and IL-6 production was highest, in contrast to TNF-α, IL-1β, and positive control, concanavalin at the tested concentration of the various fractions. Results of the current study suggest that polysaccharides extracted from P. nebrodensis have a strong anticancer effect and may be useful as an ingredient of biopharmaceutical products for treatment of cancer.

Immunomodulating and Antitumor Activities of Panellus serotinus Polysaccharides

This study was initiated in order to investigate the anticancer and immunomodulating activities of crude polysaccharides extracted in methanol, neutral saline, and hot water (hereinafter referred to as Fr. MeOH, Fr. NaCl, and Fr. HW, respectively) from the fruiting bodies of Panellus serotinus. Content of β-glucan and protein in Fr. MeOH, Fr. NaCl, and Fr. HW extracts of P. serotinus ranged from 22.92~28.52 g/100 g and 3.24~3.68 g/100 g, respectively. In vitro cytotoxicity tests, none of the various fractions of crude polysaccharides were cytotoxic against sarcoma 180, HT-29, NIH3T3, and RAW 264.7 cell lines at the tested concentration. Intraperitoneal injection with crude polysaccharides resulted in a life prolongation effect of 23.53~44.71% in mice previously inoculated with sarcoma 180. Treatment with Fr. HW resulted in an increase in the numbers of spleen cells by 1.3 fold at the concentration of 50 µg/mL compared with control. Treatment with Fr. NaCl resulted in improvement of the immuno-potentiating activity of B lymphocytes by increasing the alkaline phosphatase activity by 1.4 fold, compared with control, at the concentration of 200 µg/mL. Among the three fractions, maximum nitric oxide (13.48 µM) was recorded at 500 µg/mL in Fr. HW. Production of tumor necrosis factor alpha, interleukin-1β, and interleukin-6 was significantly higher, compared to the positive control, concanavalin A, at the tested concentration. Therefore, treatment with crude polysaccharides extracted from the fruiting body of P. serotinus could result in improvement of antitumor activity.

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.

Immunostimulatory effects of Uncaria perrottetii (A. Rich.) Merr. (Rubiaceae) vinebark aqueous extract in Balb/C mice

AIMS OF THE STUDY

Crude extract of Uncaria perrottetii (A. Rich.) Merr. vinebark was evaluated for its immunomodulating activity in Balb/C mice. Initially, the immunomodulatory potential of the plant extract was evaluated using in vitro immune response assays at different concentrations of the plant extract (10 μg/mL, 20 μg/mL, 50 μg/mL and 100 μg/mL). Using the optimum concentration determined in the in vitro assays, the protective effect of the plant extract was assessed against drug-induced immunosuppression in vivo.

MATERIALS AND METHODS

For the in vivo experiment, thirty-six (36) mice were divided into 3 groups of 12 mice each: (1) cyclophosphamide drug-induced (30 mg/kg BW) immunosuppressed mice (Cy group) served as the positive control; (2) Uncaria perrottetii extract and Cy-treated mice (U+Cy); and (3) PBS-injected mice as the negative control group [(-) CTRL].

RESULTS

The optimum concentration was determined to be 50 μg/mL in the in vitro assays. At this concentration, Uncaria perrottetii extract stimulated peritoneal phagocyte activation, produced a significant increase in the activity of phagocytic cells from the spleen and promoted splenic cellular proliferation with or without lipopolysaccharide (LPS) when compared with the PBS-treated cells (negative control). Moreover, cells treated with 50 μg/mL of Uncaria perrottetii increased macrophage respiratory burst activity that was comparable to that of the phorbol myristate acetate-stimulated splenic macrophages. In all immune assays undertaken in the in vivo experiment, the Cy-treated mice showed significantly lower response when compared with the PBS-treated mice. Significant improvement in peritoneal cell activation, phagocytic activity and cellular proliferation was exhibited by the U+Cy-treated mice when compared with Cy-injected mice. The extract from Uncaria perrottetii also significantly enhanced respiratory burst and plasma lysozyme activity compared with the Cy-injected mice.

CONCLUSIONS

Based on the results of both in vitro and in vivo trials, Uncaria perrottetii extract has immunopotentiating activities on the innate immunity of Balb/C mice and the extract could potentially reverse the immunosuppressive effects of Cy. However, the potential of the plant as source of bioactive products and metabolites for drug development still has to be fully investigated.