Studies on chemistry and immuno- modulating mechanism of a glycoconjugate from Lycium barbarum L.^†

The detailed structure of an O-glycan derived from the fruit of Lycium barbarum L. was elucidated based on glycosidic linkage analysis, complete and partial acid hydrolysis, ¹H-NMR and ¹³C NMR spectroscopy. According to the experiments, the carbohydrate was in the form of polysacchride (arabinogalactan) chains with highly branched 3, 4-galactans and terminal arabinofuranosyl substituents.

The immuno-modulating mechanism of glycoconjugate and its glycan were investigated using tritium thymidine incorporation assay, flow cytometry assay and electrophoretical mobility shift assay (EMSA). The results suggested that the immunoactive components of the fruit of Lycium barbarum L. could enhance the splenocyte proliferation in normal mice and the effects of glycan chain were stronger than those of glycoconjugate. The target cell was most likely to be B-lymphocyte, on which existed receptor binding site acting with the glycan. In addition, the immuno-stimulatory effect of glycoconjugate (LbGp4) and its glycan (LbGp4-OL) was associated with activating the expression of nuclear factor KB (NF-KB) and activator protein 1 (AP-1).