Polysaccharides from Scutellaria. I. Structure of Glucoarabinogalactan from S. adenostegia

A water-soluble polysaccharide based on glucoarabinogalactan GAG-Sa was isolated from the aerial part of Scutellaria adenostegia. The monosaccharide composition of the glucoarabinogalactan included arabinose, glucose, and galactose in a 1.0:10.9:7.6 mole ratio. GAG-Sa was characterized as a branched polysaccharide with a main chain of β-1,6-bound β-D-galactopyranose residues. The side chains of GAG-Sa consisted of 1,3-bound β-D-galactopyranose, α-D-glucopyranose, and α-L-arabinofuranose residues. The aqueous extract of the aerial part of S. adenostegia was shown to have anti-inflammatory activity.