To isolate and characterize the anti-complementary polysaccharide from the root of Echinops latifolius Tausch., bioactivity-guided fractionation and purification was used to obtain the anti-complementary polysaccharide from the hot-water extract of the root of Echinops latifolius Tausch. 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. A homogenous water-soluble polysaccharide (EPS-2A) was obtained from Echinops latifolius Tausch., which average molecular weight was estimated to be 118000. A combination of monosaccharide composition, methylation and configuration analysis, as well as NMR spectroscopy, indicated that EPS-2A was poly-(1-4)-alpha-D-galactopyranosyluronic acid in which (87.8 +/- 0.5)% of uronic acid existed as methylester. Two sulfated derivatives(Sul-2A-1 and Sul-2A-2) from EPS-2A were prepared after sulfation with 1:1 and 2:1 of chlorosulfonic acid and pyridine, respectively. The anti-complementary assay showed that Sul-2A-1 and Sul-2A-2 demonstrated a stronger inhibitory effect [ CH50 = (74.1 +/- 4.6) mu g/mL for Sul-2A-1; CH50 = (35.7 +/- 2.8) mu g/mL for Sul-2A-2] on the complement activation through the classic pathway, compared to that of heparin [CH50 = (103.0 +/- 9.0) mu g/mL]. The results suggested that the sulfated derivatives Sul-2A-1 and Sul-2A-2 might be promising drug candidates in case of necessary therapeutic complement inhibition.
[1]Shanghai Univ Tradit Chinese Med, Key Lab New Resources & Qual Evaluat Chinese Med, Key Lab Standardizat Chinese Med, Minist Educ,Inst Chinese,Inst Chinese Mat Med,SAT, Shanghai 201203, Peoples R China.
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