Chemical structure and immunomodulatory activity of a polysaccharide from Saposhnikoviae Radix

A new polysaccharide, named SP40015A01, was obtained from Saposhnikoviae Radix by water extraction, isolation and purification. SP40015A01 (9.7 x 105 Da) is composed of Rhamnose (Rha), Galacturonic acid (GalA), Galactose (Gal), and Arabinose (Ara) with the proportion of 1.6:85.6:5.8:7.6. The backbone of SP40015A01 is composed of 3-alpha-GalAp, 2-alpha-GalAp, 2,3-0-GalAp and 2,3-0-Galp, and branched at C3 of 2,30-GalAp, C3 of 2,3-0-Galp. Zebrafish experiments were used to explore the immunomodulatory activity of SP40015A01. Results showed that SP40015A01 could significantly improve the neutrophils density of immunocompromised zebrafish and reduce the content of nitric oxide (NO) and interleukin-1 beta (IL-1 beta). This study demonstrated that SP40015A01 has significant immunomodulatory activity, which can improve the neutrophils density and reduce inflammatory factor content, suggesting SP40015A01 may be a potential immunomodulator in Saposhnikoviae Radix (SR) for treatment of hypoimmunity related disease. This study supplemented the research on the polysaccharide components in traditional Chinese medicine and provided a scientific explanation for the development and clinical applications of SR.