A novel water-soluble β-d-glucan isolated from the spores of Ganoderma lucidum

Chemical features of Ganoderma polysaccharides with antioxidant, antitumor and antimicrobial activities

Ganoderma genus comprises one of the most commonly studied species worldwide, Ganoderma lucidum. However, other Ganoderma species have been also reported as important sources of bioactive compounds. Polysaccharides are important contributors to the medicinal properties reported for Ganoderma species, as demonstrated by the numerous publications, including reviews, on this matter. Yet, what are the chemical features of Ganoderma polysaccharides that have bioactivity? In the present manuscript, the chemical features of Ganoderma polysaccharides with reported antioxidant, antitumor and antimicrobial activities (the most studied worldwide) are analyzed in detail. The composition of sugars (homo- versus hetero-glucans and other polysaccharides), type of glycosidic linkages, branching patterns, and linkage to proteins are discussed. Methods for extraction, isolation and identification are evaluated and, finally, the bioactivity of polysaccharidic extracts and purified compounds are discussed. The integration of data allows deduction of structure-activity relationships and gives clues to the chemical aspects involved in Ganoderma bioactivity.

Influence of culture medium growth variables on Ganoderma lucidum exopolysaccharides structural features

In this work the effect of carbon and nitrogen levels and initial pH of the wheat extract culture medium of submerged culture of Ganoderma lucidum on the amount, purity and structural features of exopolysaccharides (EPS) were studied. A low peptone level (1.65 g L(-1)) favored mycelium biomass, EPS purity, but a higher supply of peptone (4.80 g L(-1)) is needed for maximum EPS production. The carbohydrate composition of the EPS and structural features also changed significantly according to the different growing conditions, being observed significant differences in the (1 → 3)/(1 → 4)-Glcp ratio and also on the branching degree of EPS. As the biological activities of EPS are highly dependent on the polysaccharide structural features, this variability can have implications on the EPS biological activities, but can also be used advantageously to produce tailor made polysaccharides with specific applications.

Improved production, purification and bioactivity of a polysaccharide from submerged cultured Ganoderma lucidum

Polysaccharides from Ganoderma lucidum showed multiple biological activities, such as immuno-modulating, antitumor, antioxidant, and hepatoprotective activity, etc. Adlay oil was added into the media to enhance polysaccharide production by submerged culture of G. lucidum in this work. The results revealed the optimal concentration of adlay oil was 1.5 % for polysaccharide production of G. lucidum. Analysis of the polysaccharide components confirmed that no novel components were biosynthesized by the addition of adlay oil. The main fraction of extracellular polysaccharide, GLEP-2, was isolated from the submerged culture broth of G. lucidum by ethanol precipitation, filtration, DEAE cellulose-52 and Sepharose CL-6B chromatography. GLEP-2, which was composed of glucose, galactose, mannose, arabinose, and rhamnose in a ratio of 332:55:32:13:3 respectively, had an average molecular weight of ~2.08 × 10(4) Da. The bioactivity tests demonstrated that GLEP-2 enhanced the T lymphocyte proliferation significantly at a concentration of 200 μg/mL and B lymphocyte proliferation at lower concentrations of 50 μg/mL. The results suggest polysaccharides from the submerged culture of G. lucidum are potential candidates for further development and possible commercial applications, especially in the pharmaceutical and functional foods industries.

Inducement of cytokine release by GFPBW2, a novel polysaccharide from fruit bodies of Grifola frondosa , through dectin-1 in macrophages

Polysaccharides, especially β-glucans isolated from various species of mushrooms, are considered as biological response modifiers (BRMs) to be widely used in the treatment of cancer, especially due to their immunostimulatory activity. We herein characterized the structure of a novel water-soluble homogeneous polysaccharide (GFPBW2) from the fruit bodies of mushroom Grifola frondosa and investigated its immunomodulatory activity in vitro. GFPBW2 was purified from the alkali-extracted fractions by stepwise elution with a molecular weight of 26.2 kDa. On the basis of infrared and NMR spectroscopy, methylation and monosaccharide composition analysis, partial acid hydrolysis, and Smith degradation, its structure was elucidated to possess a backbone consisting of β-d-1,3- and β-d-1,4-linked glucopyranosyl residues, with branches attached to O-6 of β-d-1,3-linked glucopyranosyl residues. Functionally, it is an effective inducer of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) secretion in murine resident peritoneal macrophages. Using quartz crystal microbalance (QCM) analysis, we found that GFPBW2 could bind dendritic cell-associated C-type lectin-1 (Dectin-1) with an affinity constant (Kd) value of 1.08 × 10 (-7) M, while it could activate Syk and enhance TNF-α production in RAW264.7 cells overexpressing wild type but not mutant Dectin-1. Furthermore, Syk, NF-κB signaling, and cytokine release in resident peritoneal macrophages induced by GFPBW2 could be significantly inhibited by a specific Dectin-1 blocking reagent, Laminarin. These data suggested that GFPBW2 might be a potential ligand of Dectin-1, and the potential of GFPBW2 to activate macrophage through triggering cytokine secretion might be attributed, at least in part, to the involvement of Dectin-1.