Carbon-13 nuclear magnetic resonance spectroscopy of some edible mushrooms.

Abstract

In this paper, carbon-13 nuclear magnetic resonance (13C-NMR) spectra of some edible mushrooms, Grifola frondosa, Lentinus edodes, Flammulina velutipes, Pholiota nameko, Agaricus bisporus, Lyophyllum cinerascens, Lyophyllum aggregatum, and Peziza vesiculosa, as aqueous suspensions were measured and the glucan compositions in these mushrooms were compared. The 13C-NMR spectrum of each native mushroom gave signals attributable to both low and high molecular weight carbohydrates. Low molecular weight carbohydrates were different in each mushroom. As high moelcular weight carbohydrates, all the mushrooms belonging to Basidiomycotina (G. frondosa, L. edodes, F. velutipes, P. nameko, A. bisporus, L. cinerascens, and L. aggregatum) showed β-linked glucan signals. G. frondosa, and P. nameko also showed α-glucan signals. After removal of low molecular weight substances and α-glucans by refluxing with 80% ethanol, dialysis or amylase digestion, all of the spectra were quite similar and showed representative signals at 104, 85, 77, 76, 74, 70, 69, 62 ppm. On the other hand, though P. vesiculosa, a fungus belonging to Ascomycotina, contains antitumor β-glucans, this mushroom showed strong signals attributable to α-glucans and only weak signals attributable to β-glucans. After treatment of G. frondosa with periodate and borohybride, most of the β-glucan signals disappeared. These results suggest that (1) 13C-NMR spectroscopy is applicable to chemotaxonomical examination of fungi, (2) all of the mushrooms belonging to Basidiomycotina contain quite similar glucans, (3) β-signals in these spectra are attributable to periodate-sensitive linkages.