Structural Features of Plantago lanceolata Mucilage

Abstract

The water soluble crude polysaccharide fraction from Plantago lanceolata leaves is composed of L-arabinose (20%),D-galactose (28%), D-glucose (6%), D-mannose (2%), L-rhamnose (4%), D-galacturonic acid (31%), D-glucuronic acid (7%) and minor amounts of L-fucose and D-xylose.
The total polysaccharide extract could be separated on DEAE-cellulose into three distinct polysaccharide fractions, two of which, FI (neutral) and FII (acidic), were subjected to further structural investigations. While FI could be fractionated into two subfractions (FIa, MW: 8000; FIb, MW: 25000) by gel chromatography, FII proved to be homogeneous (MW: 70000).

Analysis of component sugars, reduction and methylation, 13C-NMR spectroscopy and partial acid degradation studies made it possible to suggest the structural repeating units for the polysaccharides in FI and FII.