Separation and characterization of the structural features of macromolecular carbohydrates from wild edible mushrooms

Abstract

A structural characterization of two polysaccharides isolated from the fruiting bodies of the wild edible mushroom Cantharellus cibarius was performed after extraction and purification. Two polysaccharides were separated by successive aqueous extractions with boiling water and with NaOH aqueous solution (1 M, 100°C), respectively. The size exclusion chromatograms from the separated fractions showed a single peak in each fraction. The polysaccharide from the boiling water fraction (PsCcib-I) was a glucan-type carbohydrate with a molecular weight of 150 kDa. The methylation analysis and NMR experiments showed that PsCcib-I was composed of a main chain consisting of α-(1→6)-Glcp units with β-(1→4)-linked branches every third glucose residue. Differently, the polysaccharide separated from the hot aqueous NaOH fraction (PsCcib-II) had a molecular weight of 120 kDa and appeared to be a glucan-type carbohydrate composed of β-(1→3)-linked glucose units with branches at O-6 every third sugar residue. The complexation with Congo red showed that PsCcib-II displayed a triple helical conformation. © 2013 Elsevier Ltd. All rights reserved.