Heteropolysaccharides of the lichen Evernia prunastri

Extraction of Evernia prunastri with hot aqueous alkali solubilized heteropolysaccharide-containing material which was purified via Fehling precipitation. Further workup of this polysaccharide with Cetavlon gave two fractions having related but different structures. Each structure consisted of a 1 → 6-linked α-d-Manp main chain partially monosubstituted at O-2 with side chains of α-d-Galp and partially disubstituted at O-2 and O-4 with α-d-Galp and β-d-Galp, respectively. The fractions differed in that one contained much more uronic acid than the other, with corresponding predominance of side chains containing α-d-GlcpA-(1 → 3)-d-Glcp, α-d-Galp-(1 → 2)-D-Glcp, and β-d-Galf units.