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Synytsya A., Míčková K., Jablonský I., Sluková M., Čopíková J. (2008): Mushrooms of genus Pleurotus as a source of dietary fibres and glucans for food supplements. Czech J. Food Sci., 26: 441-446.Fruit bodies (separately pilei and stems) of mushrooms Pleurotus ostreatus (four strains) and Pleurotus eryngii were characterised as a source of polysaccharides. The contents of glucans and dietary fibres were determined with using the respective Megazyme enzymatic kits. Enzymatic analysis of the fruit bodies confirmed significant differences in the contents of these components among the species and strains. The stems contained more insoluble dietary fibres than the pilei in all the cases and more β-glucans in most cases. However, relatively high contents of β-glucan (20-50% of dry matter) could be a result of incomplete enzymatic hydrolysis of insoluble α-1,3-glucans. Nevertheless, low food quality stems of mushrooms Pleurotus sp. could be a valuable source of cell wall glucans for the preparation of food supplements.Keywords: mushrooms Pleurotus; glucans; dietary fibres; food supplements For millennia, humankind has been valued mushrooms as an important edible and medical resource (Chang 1980;Breene 1990;Wasser 2002). The dry matter of mushroom fruit bodies is about 5-15%, they have a very low fat content and contain 19-35% proteins. Mushroom fruit bodies are rich in vitamins, mainly B 1 , B 2 , C, and D 2 (Manzi et al. 1999;Mattila et al. 2000), and contain some important elements such as K and P (Vetter 2007). The content of carbohydrates, which are mainly present as polysaccharides or glycoproteins, ranges 50-90%; the most abundant polysaccharides are chitin, α-and β-glucans and other hemicelluloses (e.g. mannans, xylans and galactans). 442Vol. 26, No. 6: 441-446 Czech J. Food Sci. 1988). Their solubility in water strongly depends on the molecular structure and conformation. Glucans bound to proteins or to chitin are usually insoluble in water. Mushroom-derived substances with antitumour, immunomodulating, and antioxidative properties are currently used as dietary supplements. Mushroom polysaccharides with antitumour action differ greatly in their chemical compositions and configurations, as well as in their physical properties. Immunomodulatory and antitumour activities are exhibited by a wide range of glycans extending from homopolymers to highly complex heteropolymers; the differences in their activities can be correlated with the solubility in water,molecular size, branching rate and form (Augustín 1998; Ooi & Lui 1999;Wasser 2002;Novak & Vetvicka 2008). Besides the well-known antitumour β-(1→3),(1→6)-glucans (Kuniak et al. 1992(Kuniak et al. , 1998, a wide range of biologically active glucans of different structures have been described. Linear or branched polysaccharides chains occur with a backbone composed of α-or β-linked glucose units, and their various side chains can be attached in different ways. The main source of biologically active polysaccharides appears to be fungal cell walls consisti...

Oyster mushrooms are an interesting source of biologically active glucans and other polysaccharides. This work is devoted to the isolation and structural characterization of polysaccharides from basidiocarps of the cultivated oyster mushroom, Pleurotus ostreatus. Five polysaccharidic fractions were obtained by subsequent extraction with cold water, hot water and two subsequent extractions with 1 m sodium hydroxide. Branched partially methoxylated mannogalactan and slightly branched (1→6)-β-d-glucan predominated in cold- and hot-water-soluble fractions, respectively. Alternatively, these polysaccharides were obtained by only hot water extraction and subsequent two-stage chromatographic separation. The alkali-soluble parts originating from the first alkali extraction were then fractionated by dissolution in dimethyl sulfoxide (DMSO). The polysaccharide insoluble in DMSO was identified as linear (1→3)-α-d-glucan, while branched (1→3)(1→6)-β-d-glucans were found to be soluble in DMSO. The second alkaline extract contained the mentioned branched β-d-glucan together with some proteins. Finally, the alkali insoluble part was a cell wall complex of chitin and β-d-glucans.

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Within the group of higher fungi, edible medicinal mushrooms have a long history of being used as food and in folk medicine. These species contain biologically active substances with many potential beneficial effects on human health. The Pleurotus genus is representative of medicinal mushrooms because Pleurotus ostreatus is one of the most commonly cultivated culinary mushrooms. In our study, we focused on lesser-known species in the genus Pleurotus and measured their antioxidant and anti-inflammatory activity. We prepared extracts of the mushrooms and analyzed them using HPLC−HRMS, GC−MS, and 1H-NMR. Significant differences in biological activities were found among the Pleurotus spp. extracts. A MeOH extract of P. flabellatus was the most active as a radical scavenger with the highest ORAC, while a chloroform extract had significant anti-inflammatory COX-2 activity. The 80% MeOH extract of P. flabellatus contained the highest amounts of ergosterol, ergothioneine, and mannitol. The 80% MeOH extract of P. ostreatus Florida was the most active in the NF-κB inhibition assay and had the highest content of β-glucans (43.3% by dry weight). Given the antioxidant and anti-inflammatory properties of P. flabellatus, the potential therapeutic usefulness of this species is worth evaluating through in-depth investigations and confirmation by clinical trials.