title: Isolation of an anti-complementary polysaccharide from the root of Bupleurum chinense and identification of its targets in complement activation cascade.
abstract: OBJECTIVE
  To isolate and characterize the anti-complementary polysaccharide from the root of Bupleurum chinense.
  
  
  METHODS
  Bioactivity-guided fractionation and purification was used to obtain the anti-complementary polysaccharide from the hot-water extract of the root of Bupleurum chinense. The polysaccharide was characterized by various chemical and spectral analyses. The anti-complementary activities were evaluated by hemolytic assay in vitro. The action targets were identified in the system with individual complement-depleted sera.
  
  
  RESULTS
  A homogeneous polysaccharide BC-PS2 was isolated as an anti-complementary agent. It was identified as a branched polysaccharide with an average molecular weight about 2 000 KDa, composed of Glc, Ara, Gal, and Man in the ratio 3.5 : 2.4 : 2.0 : 1.0, respectively, along with a trace of Rha and Xyl, and only 1.11% of protein. The main linkages of the residues of BC-PS2 include terminal, 1, 6-linked, 1, 3-linked and 1, 3, 6-linked Glcp, terminal and 1, 5-linked Araf, terminal, 1, 4-linked, 1, 6-linked and 1, 4, 6-linked Galp, terminal, and, 1, 4-linked and 1, 4, 6-linked Manp. The bioassay experiments revealed that BC-PS2 inhibited complement activation on both the classical and alternative pathways, with CH50 and AP50 of (0.222 ± 0.013) and (0.356 ± 0.032) mg·mL(-1), respectively. Preliminary mechanism studies indicated that BC-PS2 interacted with C1q, C2, and C9 components.
  
  
  CONCLUSIONS
  The results demonstrated that BC-PS2 is an anti-complementary polysaccharide, and should be important constituent of the root of Bupleurum chinense for its application in the treatment of diseases associated with the excessive activation of complement system.
authors.affiliation: School of Pharmacy, Fudan University, Shanghai 201203, China.
authors.forename: Hong-Ye
authors.initials: HY
authors.lastname: DI
authors.forename: Yun-Yi
authors.initials: YY
authors.lastname: Zhang
authors.forename: Dao-Feng
authors.initials: DF
authors.lastname: Chen
mesh_terms: D000328:Adult; D029972:Bupleurum / Q000737:chemistry*; D002240:Carbohydrate Sequence; D003167:Complement Activation / Q000187:drug effects*; D051056:Complement Inactivating Agents / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D006461:Hemolysis / Q000187:drug effects; D006801:Humans; D008297:Male; D008970:Molecular Weight; D010936:Plant Extracts / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D018517:Plant Roots / Q000737:chemistry*; D011134:Polysaccharides / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*
chemical_list: D051056:Complement Inactivating Agents; D010936:Plant Extracts; D011134:Polysaccharides