An immunologically active pectin, named LRGP5, was firstly isolated from the fruits of Lycium ruthenicum Murr. It contained rhamnose, arabinose, xylose, galactose and galacturonic acid in the molar ratio of 1.0:2.2:0.5:1.2:4.7. Its molecular weight was estimated to be approximately 1.37 × 10(5)Da by high performance gel permeation chromatography. The structure was elucidated using methylation analysis, partial acid hydrolysis, NMR and ESI-MS analysis. Results showed that LRGP5 consisted of a (1 → 4)-linked galacturonic acid backbone occasionally interrupted by (1 → 2)-linked rhamnose. The side chains were attached to position 4 of the rhamnosyl units, including (1 → 3)-linked arabinose, (1 → 3)-linked galactose, (1 → 3,6)-linked galactose, (1 → 4)-linked galacturonic acid, (1 → 2)-linked rhamnose and (1 → 2,4)-linked rhamnose, and the termini were arabinose and rhamnose. Immunological assay results demonstrated that LRGP5 could significantly promote macrophage proliferation and enhance the secretion of nitrogen monoxide in vitro.
Keywords: Immunomodulating activity; Lycium ruthenicum; Pectin; Polysaccharide; Structure.
Crown Copyright © 2013. Published by Elsevier B.V. All rights reserved.