aInstitute of Chemistry, Komi Science Centre, The Urals Branch of the Russian Academy of Sciences, Syktyvkar, Russia
bN. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russia
KEYWORDS: Heracleum sosnowskyi; Arabinogalactan protein; Pectin; Structure; NMR; Glucomannan
Carbohydrate Polymers, 2014, v. 102, pp. 521-528
Fractions containing arabinogalactan proteins (AGP) and pectic polysaccharides were isolated from above-ground parts of Heracleum sosnowskyi. Major units of their structure were elucidated using ion-exchange chromatography, gel chromatography, and NMR spectroscopy. The carbohydrate backbone of the polysaccharides consisted of 1,3-β-D-galactopyranosyl residues, whereas side chains of the branched region consisted of the residues of 1,6-β-galactopyranose, 1,5-α-L-arabinofuranose, 1,4-β-D-glucuronic acid, and 1,6-β-D-glucopyranose. The branching points were identified as 1,3,6-β-D-galactopyranose residues. Side chains were terminated with β-D-galactopyranose, α-L-arabinofuranose and α-L-rhamnopyranose. A significant part of the side-chain β-1,6-galactan was substituted at C6 by 4-ÎÌå-β-D-glucuronic acid. A minor part of glucuronic acid was included in the α-Rhap-(1->4)-β-GlcA-(- fragment. All the studied fractions contained 1,4-β-D-galacturonic acid as well.