RESUMEN
The polysaccharide B3-PS2 was extracted and purified from Herba Scutellariae Barbatae through chromatography of DEAE-cellulose and Sephacryl S-300 column. Average molecular weight of B3-PS2 was about 1,100 kD. It was composed of Glc, Gal and Ara in the ratio of 2.7:2.7:1.0, along with trace of Man, Rha, Fuc and Xyl. B3-PS2 inhibited complement activation on the classic pathways with CH50 value of (0.23 +/- 0.03) mg mL(-1). The targets of B3-PS2 upon the complement system were C1r, C1s, C3 and C4. These results suggested that anti-complementary activity of B3-PS2 was closed to its positive control heparin. It strongly suggested that the polysaccharide B3-PS2 from Herba Scutellariae Barbatae could be a potential candidate in treating those complement-associated diseases.