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Water- and alkali-soluble glucans from oak lichen
Authors:Mirjana Hranisavljević-Jakovljević  Jelena Miljković-Stojanović  Radmila Dimitrijević  Vukic Mićović
Affiliation:Department of Chemistry, Faculty of Science, University of Belgrade, and Institute of Chemistry, Technology and Metallurgy, Belgrade Yugoslavia
Abstract:A water-soluble glucan, [α]2D +217° (water), and an alkali-soluble glucan,
/></figure> +152° (sodium hydroxide), have been isolated from the oak lichen <em>Evernia prunastri</em> (L.) Ach. On the basis of methylation analysis, periodate oxidation, and partial acid hydrolysis, the water-soluble polysaccharide has been shown to be a neutral, slightly branched glucan with a main chain composed of (1→3)- and (1→4)- linked glucopyranose residues in the ratio 1?:1. Branching occurs most probably at position 2 of (1→4)-linked glucopyranose residues. On the basis of optical rotation and i.r. spectral data, and enzymic hydrolysis, the α-D configuration has been assigned to the glycosidic linkages. Likewise, the alkali-soluble polysaccharide was shown to be a neutral, branched glucan with a main chain composed of (1→3)- and (1→4)-linked α-D-glucopyranose residues in the ratio 6:1. Each of the (1→4)-linked units was a branch point involving position 6. The presence of some β-D linkages is not excluded since hydrolysis with β-D-glucosidase occurred to a small extent.</td> </tr> <tr> <td align=
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