Indole Compounds in Some Culinary-medicinal Higher Basidiomycetes from Poland

Methanolic extracts of two species collected from natural habitats in Poland, Boletus edulis and Suillus luteus, and one species from a commercial source, Pleurotus ostreatus, were analyzed for the presence of non-hallucinogenic indole compounds. The contents of indole compounds in these species were both qualitatively and quantitatively diverse, ranging from 0.01 to 34.11 mg/100 g d.w. Two of 11 tested indole compounds, 5-hydroxytryptophan (0.18, 2.08, 1.63 mg/100 g d.w.) and serotonin (6.52, 10.14, 34.11 mg/100 g d.w.), were present in all three species under study. B. edulis and S. luteus were found to contain L-tryptophan (0.39 and 2.61 mg/100g d.w.) and melatonin (0.68 and 0.71 mg/100 g d.w.). Tryptamine was present in two species, i.e., B. edulis (1.17 mg/100 g d.w.) and in P. ostreatus (0.91 mg/100 g d.w.), in which slight amounts of indole acetonitrile (0.04 and 0.01 mg/100 g d.w., respectively) were also identified. Indoleacetic acid was a common metabolite for P. ostreatus and S. luteus and its contents amounted to 0.21 and 0.04 mg/100 g d.w., respectively. Indole compounds degradation products kynurenic acid (2.63 mg/100 g d.w.) and kynurenine sulfate were (19.57 mg/100 g d.w.) were observed only in S. luteus.