Structural Examination of Water-insoluble Alkaline-soluble Polysaccharides from Fruit Body of Lyophyllum ulmarium

Studies on Constituent of Edible Fungi Part V

Abstract

In the previous paper, we discussed the structure of polysaccharides extracted from Lyophyllum ulmarium with hot water. This paper discussed the chemical structure of polysaccharides extracted with 0.1N NaOH on 0.5N NaOH. Each extract was deproteinated by use of pronase and Sevag method, and subjected to column chromatography with Toyopearl HW-65F gel. Polysaccharide purified from the 0.1N NaOH extract was designated as P-4 and the other from 0.5N NaOH extract was designated as P-5. Homogeneity of P-4 and P-5 was confirmed by gel filtration and electrophoresis. Molecular weight of P-4 was about 105000, [α]²⁰_D was +0.27 (C=1, 0.5N NaOH) and its infrared spectrum showed absorption at 890cm^-1, suggesting the presence of β-dominant linkage. P-4 gave mannose, galactose and glucose in ratio of 1.0:1.8:4.2 after acid hydrolysis. Periodate consumption was 1.43mol/sugar residue and formic acid production was 0.61mol/sugar residue. Smith degradation products were glycerol and glucitol in a ratio of 2.6:1.0. Methylation analysis and partial acid hydrolysis sugested that P-4 possesses a highly branched structure, and the core of the molecule consisted mainly of glucose. P-5 was a glucan of molecular weight about 90000, [α]20D was +2.10 (C=1, 0.5N NaOH) and absorption was detected at 890cm-1 in infrared spectrum, suggesting the presence of β-dominant linkage. Periodate consumption was 0.45mol/sugar residue and formic acid production was 0.20mol/sugar residue. Smith degradation gave glycerol and glucitol in the ratio of 1.0:3.2. From these findings, it was assumed that P-5 possesses the structure with one branch in every 4 straight chains connected by (1→3) linkage.