Polysaccharides from the roots of Entada africana Guill. et Perr., Mimosaceae, with complement fixing activity

Entada africana is a tree used in traditional medicine in Mali. The root is, for example, used for wound-healing. Since polysaccharides from other plants are thought to play a role in the wound-healing process, we wanted to study the polysaccharides present in the root of this species. The polysaccharides were extracted with water at 50 and 100 degrees C and were further separated by anion exchange chromatography. The acidic fractions were finally purified by affinity chromatography on a Con A column. The fraction denoted Ea100 acidic I had the highest activity in the complement fixation test system, while the other acidic fractions had minor activities and the neutral fractions were almost negative. Ea100 acidic I has a structure resembling the arabinogalactan-protein type II polymer, which also was demonstrated by the abilities to precipitate with the Yariv reagent. The biological activity was reduced considerably after removal of arabinofuranoside residues by weak acid hydrolysis. The main core of the other polysaccharides extracted with 100 degrees C were pectins resembling the rhamnogalacturonan type I. These fractions also contain arabinogalactan type II structures, shown by the formation of precipitates with the Yariv reagent.