Structural studies of water-soluble polysaccharides of an edible mushroom, Termitomyces eurhizus.: A reinvestigation

The structure of two polysaccharides isolated from the hot aqueous extract of fruiting bodies of the mushroom, Termitomyces eurhizus, have been reinvestigated. These consist of two homogeneous fractions PS-I and PS-II. PS-I contains only D-glucose as the monosaccharide constituent. From methylation analysis and periodate oxidation studies, followed by GLC-MS analysis the linkages, the sugar units in PS-I were identified as (1 --> 3)-D-Glcp and (1 --> 6)-D-Glcp. PS-II contains D-glucose, and the mode of linkage Of D-glucose was identified as (1 --> 6)-D)-Glcp. Finally, the following possible structures of the polysaccharides were assigned using H-1. 2D-COSY, TOCSY, NOESY and C-13 NMR spectral analysis: [--> 6)-alpha-D-Glcp-(1]m--> [3)-alpha-D-Glcp-(l]n --> m:n = 2.5:1 PS-I (alpha-Glucan) [-->6)-alpha-D-Glcp-(1--> 6)-alpha-D-Glcp-(1-->]n PS-II (alpha-Glucan) (C) 2004 Elsevier Ltd. All rights reserved.