Immunologically Active Polysaccharide from Cetraria islandica

Abstract

A new alkali-soluble polysaccharide has been isolated from Iceland moss, Cetraria islandica (L.) Ach., by ethanol fractionation, ion-exchange chromatography, and gel filtration. The mean M_r was estimated to be 18,000. Sugar and methylation analysis, partial hydrolysis, and ¹³C-NMR spectroscopy showed the polysaccharide to be a branched galactomannan with a backbone composed of two structural elements; (1→6)-linked α-D-mannopyranosyl and α-D-(1→6)-galactopyranosyl units. The polysaccharide showed pronounced immunostimulating activity in an in vitro phagocytosis assay and in the in vivo carbon clearance assay.

Cetraria islandica - Parmeliaceae - Iceland moss - galactomannan - plant polysaccharide - immunological activity