Isolation, structural characterization, and immunological activity of a polysaccharide LRLP4-A from the leaves of Lycium ruthenicum

A water-soluble polysaccharide designated as LRLP4-A, with an average molecular weight of 135 kDa, was isolated from the leaves of Lycium ruthenicum. Structural analysis of LRLP4-A indicated that it was a highly branched polysaccharide with a backbone consisting of (1 -> 6)-linked beta-galactopyranosyl residues substituted at O-3 by arabinosyl or galactosyl residues. The branches consisted of (1 -> 3)-linked beta-Araf and alpha-Arap, (1 -> 5)-linked beta-Araf, (1 -> 3)-linked beta-Galp, and (1 -> 2, 4)-linked alpha-Rhap with a terminal alpha-Araf residue, respectively. The proposed structure of LRLP4-A was: Meanwhile, in vitro immunological activity assays demonstrated that LRLP4-A could significantly promote macrophage proliferation, increase phagocytic ability, and enhance the secretion of nitrogen monoxide in RAW246.7 cells. [GRAPHICS]