Polysaccharides from Agaricus bisporus and Agaricus brasiliensis show similarities in their structures and their immunomodulatory effects on human monocytic THP-1 cells.

BACKGROUND: Mushroom polysaccharides have traditionally been used for the prevention and treatment of a multitude of disorders like infectious illnesses, cancers and various autoimmune diseases. Crude mushroom extracts have been tested without detailed chemical analyses of its polysaccharide content. For the present study we decided to chemically determine the carbohydrate composition of semi-purified extracts from 2 closely related and well known basidiomycete species, i.e. Agaricus bisporus and A. brasiliensis and to study their effects on the innate immune system, in particular on the in vitro induction of pro-inflammatory cytokines, using THP-1 cells. METHODS: Mushroom polysaccharide extracts were prepared by hot water extraction and precipitation with ethanol. Their composition was analyzed by GC-MS and NMR spectroscopy. PMA activated THP-1 cells were treated with the extracts under different conditions and the production of pro-inflammatory cytokines was evaluated by qPCR. RESULTS: Semi-purified polysaccharide extracts of A. bisporus and A. brasiliensis (= blazei) were found to contain (1→6),(1→4)-linked α-glucan, (1→6)-linked ß-glucan, and mannogalactan. Their proportions were determined by integration of 1H-NMR signs, and were considerably different for the two species. A. brasiliensis showed a higher content of ß-glucan, while A. bisporus presented mannogalactan as its main polysaccharide. The extracts induced a comparable increase of transcription of the pro-inflammatory cytokine genes IL-1ß and TNF-α as well as of COX-2 in PMA differentiated THP-1 cells. Pro-inflammatory effects of bacterial LPS in this assay could be reduced significantly by the simultaneous addition of A. brasiliensis extract. CONCLUSIONS: The polysaccharide preparations from the closely related species A. bisporus and A. brasiliensis show major differences in composition: A. bisporus shows high mannogalactan content whereas A. brasiliensis has mostly ß-glucan. Semi-purified polysaccharide extracts from both Agaricus species stimulated the production of pro-inflammatory cytokines and enzymes, while the polysaccharide extract of A. brasiliensis reduced synthesis of these cytokines induced by LPS, suggesting programmable immunomodulation.

Polysaccharides from Pleurotus eryngii: Selective extraction methodologies and their modulatory effects on THP-1 macrophages.

Polysaccharides from P. eryngii mushroom were selectively extracted using low-cost technologies (water at different conditions of temperature and pressure). Mannogalactan was the main polysaccharide in cold-water extracted fraction (CWEF), while a linear (1→6)-ß-d-glucan was the main polymer in hot-water extracted fraction (HWEF). Autoclave-extracted fraction (AEF) contained a mixture of at least four different α- and ß-glucans. The report of linear (1→6)-ß-glucan and linear (1→3)-ß-glucan is a new finding for P. eryngii fruiting bodies. The immunostimulatory properties of the fractions on THP-1 macrophages were studied. All fractions at 50, 250 and 500 µg/mL were not cytotoxic and produced different stimulus on NO, IL-1ß and IL-10 secretion by the cells. Thus, our results showed that it is possible to concentrate different P. eryngii polysaccharides in selected fractions using a simple and low-cost procedure. Since biological effects depends on the polysaccharide structure, this technique allows the obtainment of fractions with distinct immunomodulatory activities.

High molecular weight glucan of the culinary medicinal mushroom Agaricus bisporus is an alpha-glucan that forms complexes with low molecular weight galactan.

An alpha-glucan was isolated from the culinary medicinal mushroom A. bisporus by hot water extraction, ethanol precipitation and DEAE-cellulose chromatography. The resulting material showed a single HMW peak excluded from a Sephadex G50 column that could completely be degraded by alpha-amylase treatment. After heating in 1% SDS a small additional peak of low MW eluted from the G50 column. The monosaccharide composition of the main peak was evaluated by HPLC, and was found to consist of a majority of glucose (97.6%), and a minor proportion of galactose (2.4%). Methylation analysis and degradation by alpha-amylase indicated the presence of an alpha-glucan with a main chain consisting of (1(R)4)-linked units, substituted at O-6 by alpha-D-glucopyranose single-units in the relation 1:8. Mono- (13C-, 1H-NMR) and bidimensional [1H (obs.),13C-HSQC] spectroscopy analysis confirmed the alpha-configuration of the Glcp residues by low frequency resonances of C-1 at delta 100.6, 100.2, and 98.8 ppm and H-1 high field ones at delta 5.06, 5.11, and 4.74 ppm. The DEPT-13C-NMR allowed assigning the non-substituted and O-substituted -CH(2) signals at delta 60.3/60.8 and 66.2 ppm, respectively. Other assignments were attributed to C-2, C-3, C-4, C-5 and C-6 of the non-reducing ends at delta 71.8; 72.8; 70.0; 71.3 and 60.3/60.8 ppm, respectively. The minor proportion of galactose that was demonstrated was probably derived from a complex between the alpha-glucan and a low molecular weight galactan.

Exopolysaccharides from Aspergillus terreus: Production, chemical elucidation and immunoactivity.

Aspergillus terreus, a fungus commonly used in pharmaceutical industry to produce lovastatin and other secondary metabolites, has been reported to have beneficial biological properties. In this study the exopolysaccharides (AT-EPS) produced by A. terreus were evaluated as potential modulators of certain functions of macrophages. The production parameters for EPS obtained from the liquid culture broth of the studied fungus were optimized using response surface methodology (RSM) and indicated good correlation between the experimental and predicted values. The optimum conditions for AT-EPS extraction included fermentation at 28 °C, pH 8.79, under 98 rpm of agitation, using 2.39% glucose (carbon source) and 0.957% ammonium nitrate (nitrogen source). Under these optimized conditions, AT-EPS production was 1.34 g/L medium. The chemical analyses showed that AT-EPS was composed by mannose (Man; 40.5 mol%), galactose (Gal; 35.2 mol%), and glucose (Glc; 24.3 mol%), and the spectroscopic (FTIR; NMR) and methylation analyses indicated the presence of galactomannans, ß-1,3-glucans, and glycogen-like glucans. AT-EPS was tested on murine macrophages to verify its immunoactivity and the treated cells were able to produce nitric oxide, superoxide anion, TNF-α and interleukin 6 similarly to the positive control cells. Furthermore, the macrophages treated with AT-EPS showed activated-like morphological alterations.

Anti-inflammatory and analgesic properties in a rodent model of a (1-->3),(1-->6)-linked beta-glucan isolated from Pleurotus pulmonarius.

A glucan was extracted with hot water from the basidiomycete Pleurotus pulmonarius and shown to have a (1-->3)-linked beta-D-glucopyranosyl main-chain substituted at O-6 of every third unit by single beta-D-glucopyranosyl non-reducing end units. This was shown by mono- and bidimensional nuclear magnetic resonance (NMR) spectroscopy, methylation analysis, and a controlled Smith degradation. The glucan was tested for its effects on the acetic acid-induced writhing reaction in mice, a typical model for quantifying inflammatory pain. It caused a marked and dose-dependent anti-inflammatory response, demonstrated by the inhibition of leukocyte migration to injured tissues (82 +/- 6%) with an ID50 of 1.19 (0.74-1.92) mg/kg. Furthermore, animals previously treated with the glucan (3 mg/kg i.p.), showed a reduction of 85 +/- 5% of writhes, after receiving the acetic acid injection. Furthermore, in the formalin test, the glucan (3-30 mg/kg, i.p.) also caused significant inhibition of both the early (neurogenic pain) and the late phases (inflammatory pain) of formalin-induced licking. However, it was more potent and effective in relation to the late phase of the formalin test, with mean ID(50) values for the neurogenic and the inflammatory phases of > 30 and 12.9 (6.7-24.6) mg/kg and the inhibitions observed were 43 +/- 5% and 96 +/- 4%, respectively. These data showed that the glucan had potent anti-inflammatory and analgesic (antinociceptive) activities, possibly by the inhibition of pro-inflammatory cytokines.

Yacon fructans (Smallanthus sonchifolius) extraction, characterization and activation of macrophages to phagocyte yeast cells.

Yacon (Smallanthus sonchifolius) originates from the Andean region and has spread across South America, Europe and Japan. In contrast with most roots, yacon stores its carbohydrates in fructooligosaccharides (FOS) and contains approximately 37% of FOS in its root dry matter. Aqueous extracts of yacon were characterized through TLC, methylation, NMR, and ESI-MS. FOS of yacon showed as linear fructooligosaccharides containing almost exclusively (2→1)-linked ß-fructofuranosyl units, with terminal α-glucopyranosyl and ß-fructofuranosyl units. ESI-MS analyses indicated a wide degree of polymerization (DP) ranging from 2 to 10. The effect of the isolated FOS on non-specific immune activity by THP-1 cells was evaluated through phagocytic activity against heat-killed yeast (Saccharomices cerevisiae). The stimulant effect of yacon FOS was dose- and time-dependent, showing results more effective than branched FOS observed in previous studies. The results reinforce the use of linear yacon FOS as immunomodulators.

Simple and effective purification approach to dissociate mixed water-insoluble α- and ß-D-glucans and its application on the medicinal mushroom Fomitopsis betulina.

Differences in anomericity and in the branching degree of glucans lead to characteristic intermolecular association that influences their solubility in water or other solvents. A simple purification approach, based on the glucan solubility in aq. 0.1 M NaOH solution, was applied for the separation of mixed water-insoluble α-D-glucans from ß-D-glucans extracted from fruiting bodies of Fomitopsis betulina, which is an underexploited medicinal mushroom. The results indicated that the ß-D-glucan is constituted by (1→3)-linked ß-D-Glcp units substituted at O-6 by non-reducing ß-D-Glcp and (1→6)-linked ß-D-Glcp units, while the α-D-glucan has a linear (1→3)-linked glucan structure. Thus, the 0.1 M NaOH treatment proved to be a simple, efficient and low-cost purification method for separation of water-insoluble glucans with different anomeric configurations and degree of branching that were interacting by intermolecular forces.

Chemical characterization and wound healing property of a ß-D-glucan from edible mushroom Piptoporus betulinus.

A water-soluble ß-D-glucan was obtained from fruiting bodies of Piptoporus betulinus, by hot aqueous extraction followed by freeze-thawing procedure and dialysis. Its molar mass distribution and conformational behavior in solution was assessed by size-exclusion chromatography coupled with multiangle laser light scattering, showing a polysaccharide with an average molecular weight of 2.5 × 105 Da with a random coil conformation for molecular weights below 1 × 106 Da. Typical signals of ß-(1 → 3)-linkages were observed in NMR spectrum (δ 102.7/4.76; 102.8/4.74; 102.9/4.52; and δ 85.1/3.78; 85.0/3.77) and also signals of O-6 substitution at δ 69.2/4.22 and 69.2/3.87. The analysis of partially O-methylated alditol acetates corroborates the NMR results, indicating the presence of a ß-D-glucan with a main chain (1 → 3)-linked, substituted at O-6 by single-units of glucose. The ß-D-glucan showed no toxicity on human colon carcinoma cell line (Caco-2) up to 1000 µg mL-1 and promoted cell migration on in vitro scratch assay, demonstrating a potential wound healing capacity.

Water-Soluble Polysaccharide Extracts from the Oyster Culinary-Medicinal Mushroom Pleurotus ostreatus (Agaricomycetes) with HMGCR Inhibitory Activity.

Water extracts from Pleurotus ostreatus containing no statins showed 3-hydroxy-3-methyl-glutaryl CoA reductase (HMGCR) inhibitory activity (in vitro) that might be due to specific water-soluble polysaccharides (WSPs); when isolated and deproteinized, increasing concentrations of the WSP extract induced higher inhibition. The WSP extract contained mainly ß-glucans, mannogalactans, and glycogen (e.g., α-glucans), although derivatives or fragments with lower molecular weights (between 14 and 3.5 kDa) were present and were able to induce the inhibitory activity. The extract contained more ß-(1→3)-glucans than ß-(11→3),(11→6)-glucans, and they partially survived digestion and managed to pass through Caco2 cell monolayers to the lower compartment after in vitro digestion and transport experiments. The WSP might also modulate Caco2 membrane integrity.

Structural characterization of a polysaccharide and a beta-glucan isolated from the edible mushroom Flammulina velutipes.

Two polysaccharides were isolated from the basidiomycete Flammulina velutipes, via successive hot extraction with water, 2% and 25% aq. KOH, and then submitted to freeze-drying. The precipitate formed by repeated freeze-thawing from the 2% aq. KOH extraction PK2 was analyzed by determination of its monosaccharide composition, as well as by methylation analyses using GC-MS, mono- ((13)C, (1)H NMR) and bidimensional ((1)H (obs.), (13)C HMQC) spectroscopy, and controlled Smith degradations. It was established to be a branched beta-glucan, with a main chain of (1-->3)-linked-Glcp residues, substituted at O-6 by single-unit beta-Glcp side chains. The precipitate formed by repeated freeze-thawing from the 25% KOH extraction PK25 contained Xyl, Man, and Glc and was heterogeneous by HSPEC and extraction with DMSO gave a soluble xylomannan (XM). It was homogeneous with a molar mass 30.8 x 10(4)g/mol (dn/dc=0.186). Using the above chemical analyses, it was a xylomannan with Man and Xyl in a 3:2 molar ratio. Its main chain consisted of (1-->3)-linked alpha-Manp units, mainly substituted at O-4 by beta-Xylp units or with some beta-Xylp-(1-->3)-beta-Xylp groups.

Mushroom heteropolysaccharides: A review on their sources, structure and biological effects.

Mushrooms have been largely studied not only by their d-glucans, but also because they present a class of more complex polymers: the heteropolysaccharides. Heteropolysaccharides show variability on their monosaccharide composition, anomeric configuration, linkage and branching type, besides some of these molecules can present natural methylated monosaccharides and also acid monosaccharides, which enhance the difficulty of the purification and characterization of their structure. As a result of such complexity, mushroom heteropolysaccharides can be considered an interesting source of molecules with medicinal and industrial applications. Consequently a plenty of new researches has been published in the past 12 years about the isolation, chemical characterization and biological activities of heteropolysaccharides from mushrooms, especially from Basidiomycetes. Therefore, this review intends to organize and classify the information described up to now about such polysaccharides obtained from different sources of mushroom-forming fungi, Basidiomycetes, Ascomycetes and Hybrid mushrooms, and provides a brief reflection on how the chemical studies have been carried out.

Water-Soluble Compounds from Lentinula edodes Influencing the HMG-CoA Reductase Activity and the Expression of Genes Involved in the Cholesterol Metabolism.

A water extract from Lentinula edodes (LWE) showed HMG-CoA reductase inhibitory activity but contained no statins. NMR indicated the presence of water-soluble α- and ß-glucans and fucomannogalactans. Fractions containing derivatives of these polysaccharides with molecular weight down to approximately 1 kDa still retained their inhibitory activity. Once digested LWE was applied to Caco2 in transport experiments, no significant effect was noticed on the modulation of cholesterol-related gene expression. But, when the lower compartment of the Caco2 monolayer was applied to HepG2, some genes were modulated (after 24 h). LWE was also administrated to normo- and hypercholesterolemic mice, and no significant lowering of serum cholesterol levels was observed; but reduction of triglycerides in liver was observed. However, LWE supplementation modulated the transcriptional profile of some genes involved in the cholesterol metabolism similarly to simvastatin, suggesting that it could hold potential as a hypolipidemic/hypocholesterolemic extract, although further dose-dependent studies should be carried out.

Exopolysaccharide produced by Pleurotus sajor-caju: its chemical structure and anti-inflammatory activity.

Edible mushrooms are high nutritional value foods, which contain proteins, fibers, minerals, vitamins, and carbohydrates. Among their carbohydrates are some polysaccharides with recognized therapeutic effects. It was reported in this manuscript the structural characterization and antinociceptive and anti-inflammatory activities of an exopolysaccharide (EPS) produced by Pleurotus sajor-caju. The purified EPS was a mannogalactan (PEIsR), which was composed by mannose (37.0%), galactose (39.7%), and 3-O-methyl-galactose (23.3%). The polysaccharide was purified by freeze-thawing and dialysis, and it was characterized by GC-MS analysis and NMR spectroscopy. The mannogalactan is constituted by a main chain of (1 → 6)-linked α-D-Galp and 3-O-methyl-α-D-Galp units. Some of the α-D-Galp units were substituted at O-2 by non-reducing end units of ß-D-Manp. According to the literature review conducted, this is the first time that a methylated polysaccharide was observed on EPS of P. sajor-caju. The mannogalactan was able to reduce the nociception, in vivo, in the writhing and formalin tests and also reduced the carrageenan-induced paw edema, which indicates that it could be an effective antinociceptive and anti-inflammatory agent.

Anti-inflammatory properties of the medicinal mushroom Cordyceps militaris might be related to its linear (1→3)-ß-D-glucan.

The Ascomycete Cordyceps militaris, an entomopathogenic fungus, is one of the most important traditional Chinese medicines. Studies related to its pharmacological properties suggest that this mushroom can exert interesting biological activities. Aqueous (CW and HW) and alkaline (K5) extracts containing polysaccharides were prepared from this mushroom, and a ß-D-glucan was purified. This polymer was analysed by GC-MS and NMR spectrometry, showing a linear chain composed of ß-D-Glcp (1→3)-linked. The six main signals in the 13C-NMR spectrum were assigned by comparison to reported data. The aqueous (CW, HW) extracts stimulated the expression of IL-1ß, TNF-α, and COX-2 by THP-1 macrophages, while the alkaline (K5) extract did not show any effect. However, when the extracts were added to the cells in the presence of LPS, K5 showed the highest inhibition of the pro-inflammatory genes expression. This inhibitory effect was also observed for the purified ß-(1→3)-D-glucan, that seems to be the most potent anti-inflammatory compound present in the polysaccharide extracts of C. militaris. In vivo, ß-(1→3)-D-glucan also inhibited significantly the inflammatory phase of formalin-induced nociceptive response, and, in addition, it reduced the migration of total leukocytes but not the neutrophils induced by LPS. In conclusion, this study clearly demonstrates the anti-inflammatory effect of ß-(1→3)-D-glucan.

Structural characterization and anti-inflammatory activity of a linear ß-D-glucan isolated from Pleurotus sajor-caju.

Glucans comprise an important class of polysaccharides present in basidiomycetes with potential biological activities. A (1 → 3)-ß-D-glucan was isolated from Pleurotus sajor-caju via extraction with hot water followed by fractionation by freeze-thawing and finally by dimethyl sulfoxide extraction. The purified polysaccharide showed a (13)C-NMR spectrum with six signals consisting of a linear glucan with a ß-anomeric signal at 102.8 ppm and a signal at 86.1 ppm relative to O-3 substitution. The other signals at 76.2, 72.9, 68.3, and 60.8 ppm were attributed to C5, C2, C4, and C6, respectively. This structure was confirmed by methylation analysis, and HSQC studies. The ß-d-glucan from P. sajor-caju presented an immunomodulatory activity on THP-1 macrophages, inhibited the inflammatory phase of nociception induced by formalin in mice, and reduced the number of total leukocytes and myeloperoxidase levels induced by LPS. Taken together, these results demonstrate that this ß-d-glucan exhibits a significant anti-inflammatory activity.

Glucuronoarabinoxylan from coconut palm gum exudate: chemical structure and gastroprotective effect.

A glucuronoarabinoxylan (CNAL) was extracted with 1% aq. KOH (25°C) from Cocos nucifera gum exudate. It had a homogeneous profile on HPSEC-MALLS-RI (Mw 4.6 × 10(4)g/mol) and was composed of Fuc, Ara, Xyl, GlcpA (and 4-O-GlcpA) in a 7:28:62:3 molar ratio. Methylation data showed a branched structure with 39% of non-reducing end units, 3-O-substituted Araf (8%), 3,4-di-O- (15%), 2,4-di-O- (5%) and 2,3,4-tri-O-substituted Xylp units (17%). The anomeric region of CNAL (13)C NMR spectrum contained 9 signals, indicating a complex structure. The main chain of CNAL was characterized by analysis of a Smith-degraded polysaccharide. Its (13)C NMR spectrum showed 5 main signals at δ 101.6, δ 75.5, δ 73.9, δ 72.5, and δ 63.1 that were attributed to C-1, C-4, C-3, C-2 and C-5 of (1→4)-linked ß-Xylp-main chain units, respectively. CNAL exhibited gastroprotective effect, by reducing gastric hemorrhagic lesions, when orally administered (1 and 3mg/kg) to rats prior to ethanol administration.

Isolation and chemical characterization of a glucogalactomannan of the medicinal mushroom Cordyceps militaris.

Cordyceps militaris dried fruiting bodies were extracted with 5% KOH solution. The extract was purified by freeze-thawing treatment, and dialysis (100 kDa), giving rise to a homogeneous polysaccharide (Mw 23,000 Da). Its monosaccharide composition was mannose (56.7%), galactose (34.5%), and glucose (8.8%). The anomeric configurations were determined by their coupling constants. A complex polysaccharide was identified by NMR and methylation analysis. The HSQC spectrum showed signals at δ 107.7/5.06 and 106.1/5.14; 105.9/5.12 relative to ß-d-Galf, and O-2-substituted ß-d-Galf units, respectively. The sign at δ 104.4/5.21 corresponded to α-d-Galf. Other signals corresponded to α-d-Manp O-6- and O-2-substituted (δ 100.2/4.94; 100.5/5.27; 100.6/5.23; 100.7/5.16), and α-d-Manp 2,6-di-O-substituted (from δ 99.3 to 99.9). The main linkages, confirmed by methylation analysis, showed the derivatives: 2,3,4-Me3-Manp (11.9%) and 3,4,6-Me3-Manp (28.6%). The branches were (1→6)-linked-α-d-Manp or (1→2)-linked-ß-d-Galf, terminating with ß-d-Galf, α-d-Galf, α-d-Galp, or α-d-Manp. 42.7% of the partially hydrolyzed product consisted of 3,4,6-Me3-Manp, suggesting a (1→2)-linked backbone.

Agaricus bisporus and Agaricus brasiliensis (1→6)-ß-D-glucans show immunostimulatory activity on human THP-1 derived macrophages.

The (1→6)-ß-D-glucans from Agaricus bisporus and Agaricus brasiliensis were purified to evaluate their effects on the innate immune system. THP-1 macrophages were used to investigate the induction of the expression of TNF-α, IL1ß, and COX-2 by RT-PCR. The purification of the polysaccharides gave rise to fractions containing 96-98% of glucose. The samples were analyzed by GC-MS, HPSEC and (13)C NMR, which confirmed the presence of homogeneous (1→6)-ß-D-glucans. The ß-glucans were incubated with THP-1 derived macrophages, for 3 h and 6 h to evaluate their effects on the expression of pro-inflammatory genes. Both ß-glucans stimulated the expression of such genes as much as the pro-inflammatory control (LPS). When the cells were incubated with LPS+ß-glucan, a significant inhibition of the expression of IL-1ß and COX-2 was observed for both treatments after 3 h of incubation. By the results, we conclude that the (1→6)-ß-D-glucans present an immunostimulatory activity when administered to THP-1 derived macrophages.