Plant mucilages. XLIII. A representative mucilage with biological activity from the leaves of Hibiscus rosa-sinensis.

A representative mucilage, called Hibiscus-mucilage RL, was isolated from the leaves of Hibiscus rosa-sinensis L. It was homogeneous on electrophoresis, and its molecular mass was estimated to be roughly 1.0 x 10(7). Its intrinsic viscosity value in aqueous solution was 23.2. The major constituent is an acidic polysaccharide composed of L-rhamnose: D-galactose: D-galacturonic acid: D-glucuronic acid in the molar ratio of 5:8:3:2. Methylation analysis, partial hydrolysis and nuclear magnetic resonance studies indicated its main structural features including a unique backbone chain composed of alpha-1,4-linked D-galactosyl alpha-1,2-linked L-rhamnosyl alpha-1,4-linked D-galacturonic acid units. The mucilage showed considerable anti-complementary activity.