Anti-complementary acidic polysaccharides from roots of Lithospermum euchromum.

Extremely potent complement activating (anti-complementary) polysaccharides from roots of Lithospermum euchromum were fractionated in a novel way and also assayed for mitogenic and enhancing activity of immune complex binding to macrophages in vitro. Anti-complementary activity and enhancing activity of immune complex binding were observed in the different polysaccharide fractions, but no mitogenic activity was found. The acidic polysaccharide fraction (LR-2) which had the most potent anti-complementary activity was highly heterogeneous, and on further fractionation gave active polysaccharides. Extremely potent anti-complementary polysaccharides, LR-2IId-1a, LR-2IId-1b, LR-2IId-3a and LR-2IId-5a were characterized chemically. These consisted mainly of mannose, galactose, glucose and glucuronic acid, in addition to rhamnose, fucose and arabinose as minor components. Methylation analysis showed that the four polysaccharides contained mainly (1-->3)-linked galactose, (1-->3)-linked fucose and (1-->4)-linked glucose. (1-->3)-Linked mannose was also detected in LR-2IId-1a, 1b and 5a, and (1-->4)-linked glucuronic acid in LR-2IId-1a and 1b as the major glycosidic linkages.