Immunomodulating activities of cultivated maitake medicinal mushroom Grifola frondosa (Dicks.: Fr.) S.F. Gray (higher Basidiomycetes) on peripheral blood mononuclear cells.

Grifola frondosa is a culinary-medicinal mushroom that contains several physiologically active compounds, of which polysaccharides, specifically ß-glucans, are known to possess immunomodulating properties. Its extracts are studied for application as adjuncts for chemotherapy, and experiments in animal models support the use of this mushroom for cancer treatment. The effect of extracts obtained from mushrooms cultivated on different substrates and their capacity of inducing the secretion of cytokines from human peripheral blood mononuclear cells were studied. The activity of extracts at concentrations 12.5, 100, and 200 µg/mL on induction of TNF-α, IFN-γ, and IL-12 was screened. Two extracts from substrates fortified with olive oil press cakes showed appreciable activity and induced the secretion of TNF-α, IL-12, and INF-γ. The extracts differed from the others in the amount of sugar, protein, and ß-glucans, which can explain their higher activity. Present results show that different substrates and different source materials can reasonably modify the bioactivity of cultivated G. frondosa.

Solid-state cultivation of Grifola frondosa (Dicks: Fr) S.F. Gray biomass and immunostimulatory effects of fungal intra- and extracellular beta-polysaccharides.

Grifola frondosa strain GF3, was cultivated on solid-state substrate consisting of milled whole corn plant (Zea mays) and olive press cake supplemented with mineral additives and olive oil. Maintenance of the moisture content in the solid substrate is of crucial importance. Moistures higher than 70% promote growth of G. frondosa mycelium and polysaccharide production. Four fractions of pure extracellular beta-D-glucans with total mass 127.2mg and four fractions of intracellular polysaccharides with total mass 47.2mg were isolated. Polysaccharides were further separated by ion-exchange, gel and affinity chromatography. Isolated polysaccharide fractions from fungal mycelium proved to induce moderate amounts of TNF-alpha in PBMC cells in vitro. The extent of TNF-alpha induction was up to 322pgmL(-1) at a polysaccharide concentration of 200microgmL(-1) for the intracellular fraction. The TNF-alpha inducing activity is comparable to romurtide, which has been used as a supporting therapy in cancer patients treated with radiotherapy and/or chemotherapy.