Structural Characterization and Anticomplement Activity of an Acidic Heteropolysaccharide from Lysimachia christinae Hance.

A novel acidic heteropolysaccharide (LCP-90-1) was isolated and purified from a traditional "heat-clearing" Chinese medicine, Hance. LCP-90-1 (, 20.65 kDa) was composed of Man, Rha, GlcA, Glc, Gal, and Ara, with relative molar ratios of 1.00: 3.00: 11.62: 1.31: 1.64: 5.24. The backbone consisted of 1,4--D-GlcA, 1,4--D-Glc, 1,4--L-Rha, and 1,3,5--L-Ara, with three branches of -D-Gal-(1 → 4)--L-Rha-(1→, -L-Ara-(1→ and -D-Man-(1→ attached to the C-5 position of 1,3,5--L-Ara. LCP-90-1 exhibited potent anticomplement activity (CH: 135.01 ± 0.68 µg/mL) , which was significantly enhanced with increased glucuronic acid (GlcA) content in its degradation production (LCP-90-1-A, CH: 28.26 ± 0.39 µg/mL). However, both LCP-90-1 and LCP90-1-A were inactivated after reduction or complete acid hydrolysis. These observations indicated the important role of GlcA in LCP-90-1 and associated derivatives with respect to anticomplement activity. Similarly, compared with LCP-90-1, the antioxidant activity of LCP-90-1-A was also enhanced. Thus, polysaccharides with a high content of GlcA might be important and effective substances of .