[Polysaccharides from Nerium oleander: structure and biological activity]

A water extraction of crushed leaves of Nerium oleander yielded 2.3% of a crude polysaccharide. The main fraction (67%) represents a pectic polysaccharide mainly composed of galacturonic acid besides rhamnose, arabinose and galactose. The polysaccharide structure was characterized by NMR, mild acid- and pectinase treatment combined with GC-MS analyses. In vivo tests for a possible antitumor activity did not result in a significant action. Investigation of immunomodulating activity brought some indications for mitogenic activity and a weak macrophage-mediated cytotoxicity. Increase of phagocytosis could not be doubtlessly assigned to the polysaccharide due to the high amount of endotoxin in the homogenous fraction OLE 2.