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, Lysimachia christinae Hance. LCP-90-1 (Mw , 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- α -D-Glc p A, 1,4- α -D-Glc p , 1,4- β -L-Rha p , and 1,3,5- α -L-Ara f , with three branches of β -D-Gal p -(1 → 4)- β -L-Rha p -(1→, α -L-Ara f -(1→ and α -D-Man p -(1→ attached to the C-5 position of 1,3,5- α -L-Ara f. LCP-90-1 exhibited potent anticomplement activity (CH50 : 135.01 ± 0.68 µg/mL) in vitro , which was significantly enhanced with increased glucuronic acid (GlcA) content in its degradation production (LCP-90-1-A, CH50 : 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 L. christinae. [ABSTRACT FROM AUTHOR]