Antitumor Properties of Aqueous Extracts from Inonotus rheades Mycelium and Their Evaluation under Various Cultivation Conditions.

The antitumor properties of aqueous extracts of Inonotus rheades basidiomycete mushrooms were evaluated when the fungi were cultured on wood discs and wood shavings (birch) at 25 ± 1°C in the dark and under constant illumination with blue light (12.8 W/m2). The aqueous fraction containing water-soluble polysaccharides was isolated and analyzed: WS-5 fraction cultured on wood discs under blue light illumination, WS-8 fraction grown under similar conditions on wood shavings; WS-6 fraction grown in the dark on wood discs; and WS-7 fraction grown under similar conditions on wood shavings. The antitumor effects of the extracts were studied on the model of Ehrlich ascites carcinoma in mice. It was found that the extracts isolated from the basidial fungus Inonotus rheades exhibit antitumor properties and that their accumulation during growth is determined by different cultivation conditions.

New Inonotus Polysaccharides: Characterization and Anticomplementary Activity of Inonotus rheades Mycelium Polymers.

Inonotus is a small genus of xylotrophic basidiomycetes and a source of bioactive fungochemicals among which a special place is occupied by polymeric compounds. In this study, polysaccharides that are widespread in Europe, Asia, and North America and a poorly understood fungal species, I. rheades (Pers.) Karst. (fox polypore), were investigated. Water-soluble polysaccharides of I. rheades mycelium were extracted, purified, and studied using chemical reactions, elemental and monosaccharide analysis, UV-Vis and FTIR spectroscopy, gel permeation chromatography, and linkage analysis. Five homogenic polymers (IRP-1-IRP-5) with molecular weights of 110-1520 kDa were heteropolysaccharides that consist mainly of galactose, glucose, and mannose. The dominant component, IRP-4, was preliminary concluded to be a branched (1→3,6)-linked galactan. Polysaccharides of I. rheades inhibited the hemolysis of sensitized sheep erythrocytes by complement from human serum, signifying anticomplementary activity with the greatest effects for the IRP-4 polymer. These findings suggest that I. rheades mycelium is a new source of fungal polysaccharides with potential immunomodulatory and anti-inflammatory properties.