Wheat-spike-shaped arabinans from Lycium barbarum by alkaline scission-Cascade refinement and its dual-immunomodulatory activity.

To preclude the loss of glycan moieties inherent to the Sevag-mediated deproteination of Lycium barbarum polysaccharides (LBP), this study employed controlled alkaline hydrolysis instead of the classical chloroform-butanol precipitation, subsequently implemented a gradient ethanol-precipitation scheme. This strategy yielded an arabinogalactan fraction and a novel polysaccharide fraction (ALBP-80) from Lycium barbarum. The ALBP-80 was further purified by Bio-gel P100 column chromatography to obtain homogeneous fraction (ALBGP-80). Through chemical methods (monosaccharide composition, methylation analysis) and spectroscopic techniques (GC, GC-MS, NMR), we indicated that ALBGP-80 is a neutral polysaccharide with a molecular weight of 22.78 kDa and its sugar chain is composed solely of arabinose. Its backbone consists of repeating structural units of →5)-α-Araf-(1→, with each sugar unit substituted at the C-2 position by T-α-Araf-(1→, resulting in a wheat-spike-shaped neutral polysaccharide. Additionally, in vitro studies demonstrated that ALBGP-80 as a natural dual-immunomodulator, capable of both immunoactivation and immunosuppression responses than arabinogalactan fraction. These findings establish a foundation for transitioning Lycium barbarum from a traditional food resource into a novel functional food with immune-supporting properties.