Chemical constituents of Stereum subtomentosum and two other birch-associated basidiomycetes: An interspecies comparative study

Metabolites of the wood-rotting fungus Stereum subtomentosum POUZAR (Basidiomycetes, order Russulales, family Stereaceae) occuring on birch (Betula pendula ROTH) trees were phytochemically investigated for the first time. Three main metabolite chemotypes present in MeOH extracts of the fruit bodies, Viz. steroids, fatty acids, and water-soluble sugars, were fractionated, isolated, and identified by 1D/2D NMR-spectroscopic analyses, NMR data comparisons, and chemical correlations combined with GC/MS experiments. Thirteen compounds including two 5 alpha,8 alpha-epidioxy steroids, alpha,alpha'-trehalose, D-arabinitol, D-mannitol, and saturated/unsaturated fatty acids, were identified. Differences among S. subtomentosum and two other birch-associated fungal species, Trametes versicolor (L.: FR.) PILAT, and Piptoporus betulinus (BULL.: FR.) P. KARST (Basidiomycetes, order Polyporales, family Polyporaceae) were evaluated as regards the richness and abundance relationships in metabolite profiling.