Studies on molecular weights of polysaccharides of Auricularia auricula-judae

Three d-glucans (A, C, and E) and two acidic heteropolysaccharides (D and B), isolated from the fruit bodies of Auricularia auricula-judae (which grows in Fangshan, Hubei, China) were analysed by paper chromatography, gas chromatography, and IR and 13 C NMR. Glucans A, C, and E consist mainly of a backbone chain of β-(1 → 3)-d-glucose residues, with various branched groups. Polysaccharides D and B contain residues of d-xylose, d-mannose, d-galactose, d-glucose, and d-glucuronic acid. The weight-average molecular weights Mw, number-average molecular weights Mw, intrinsic viscosities [ν], and Huggins constants k′ of these polysaccharides were studied by light scattering, membrane osmometry, and viscometry. The values of Mw for samples of A, C, E, D, and B are 117 × 104, 144 × 104, 200 × 104, 30 × 104, and 50 × 104, respectively. Analysis of the Mw, Mn, [ν], and k′ data indicates polysaccharides A and E to have stiff chains, and C, D, and B flexible chains in aqueous solutions.