An anti-complementary polysaccharide from the roots of Bupleurum chinense

Bioactivity-guided fractionation of hot-water extract from the roots of Bupleurum chinense DC led to the isolation of a homogeneous polysaccharide BC-PS1 composed of Gal, GalA, Glc, Ara and Man in the ratio of 1.6:1.1:1.8:1.7:1.0, along with trace of Rha, Fuc and Xyl. The main linkages of the residues of BC-PS1 include terminal, 1,4-linked and 1,3-linked Galp (GalA), terminal and 1,4-linked Glcp, terminal and 1,5-linked Araf, 1,4,6-linked Manp. Bioassays revealed that the concentrations of BC-PS1 that resulted in 50% hemolytic inhibition on classical complement pathway (CH50) and alternative complement pathway (AP50) were 0.199 ± 0.025 mg/mL and 0.371 ± 0.017 mg/mL, respectively. Preliminary mechanism study indicated that BC-PS1 interacted with C1q, C2, C5 and C9.