Structural elucidation of an immunological arabinan from the rhizomes of Ligusticum chuanxiong, a traditional Chinese medicine

In the present study, an immunological arabinan, LCP70-2A, was isolated from Ligusticum chuanxiong for the first time. The absolute molecular weight of LCP70-2A was determined to be 6.46 x 10(4) g/mol using the HPSEC-MALLS-RID method. The absolute configuration of arabinose in LCP70-2A was determined to be L-configuration. Physicochemical characterization revealed that LCP70-2A was a homogeneous polysaccharide and had a backbone of (1 -> 5)-linked alpha-L-Araf with terminal alpha-L-arabinose residues at position O-2 and O-3. Molecular conformation analysis showed that LCP70-2A was a branching polysaccharide with a compact coil chain conformation in 0.1 M NaCl solution. In addition, in vitro cell assays showed that LCP70-2A can activate macrophages by enhancing the phagocytosis and potentiating the secretion of immunoregulatory factors including NO, TNF-alpha, IL-6, and IL-1 beta. Furthermore, LCP70-2A was proved to promote the production of ROS and NO using the zebrafish model, suggesting that LCP70-2A can be further developed as a candidate supplement for immunological enhancement. (C) 2020 Elsevier B.V. All rights reserved.

Automated summary

In this study, an immunological arabinan, LCP70-2A, was isolated from Ligusticum chuanxiong for the first time. Physicochemical characterization revealed its homogeneous polysaccharide nature and potential as an immunological enhancement supplement by activating macrophages and promoting the secretion of immunoregulatory factors.