中文摘要：

目的：从北柴胡根中分离表征具有抗补体活性的多糖成分。方法：以抗补体活性为导向从北柴胡根水提物中分离纯化活性多糖；化学和谱学方法表征多糖的理化性质；采用体外细胞溶血试验法测定抗补体活性；并利用补体成分缺失血清鉴定补体激活过程中的作用靶点。结果：获得一个均一多糖BC．PS2，是一个具分支结构的杂多糖，平均分子量2000KDa，其单糖摩尔比为：葡萄糖／阿拉伯糖／半乳糖／甘露糖=3．5：2．4：2．0：1．0，并含有少量的鼠李糖和木糖以及蛋白（1．11％）；单糖的主要连接方式包括：末端、1，3-、1，6．和1，3，6．连接的葡萄糖，末端、1，5-连接的阿拉伯糖，末端、1，4一、1，6一和1，4，6-连接的半乳糖，末端、1，4-和1，4，6-连接的甘露糖；BC-PS2对补体激活的经典和旁路途径均有抑制作用，CH50和AP50分别为（0．222±0．013）和（0．356±0．032）mg·mL^-1；靶点研究结果表明BC．PS2作用于补体成分clq，c2和c9。结论：BC—PS2是一个具有抗补体活性的多糖成分，应该是柴胡治疗与补体过度激活相关疾病的药效成分之一。

英文摘要：

AIM： 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, 6-1inked, 1, 3-1inked and 1, 3, 6-1inked Glcp, terminal and 1, 5-1inked Araf, terminal, 1, 4-1inked, 1, 6-1inked and 1, 4, 6-1inked Galp, terminal, and, 1, 4-1inked and 1, 4, 6-1inked Manp. The bioassay experiments revealed that BC-PS2 inhibited complement activation on both the classical and alternative pathways, with CHs0 and APs0 of （0.222 ± 0.013） and （0.356 ± 0.032） mg·mL^-1, respectively. Preliminary mechanism studies indicated that BC-PS2 interacted with Clq, C2, and C9 components. CONCLUSION： The results demonstrated that BC-PS2 is an anti-complementary polysaccharide, and should be important constituent of the root ofBupleurum chinense for its application in the treatment of diseases associated with the excessive activation of complement system.