5.15.1. Ulmus pumila L

U. pumila (Siberian elm) is a medicinal plant widespread in whole Asia, the roots and barks of which are known to contain pectins with a marked anti-oxidant activity (Zhou et al., 2017). The one reported by Lee and coworkers in 2017 represents the only example of selenylation of a pectic polysaccharide. These authors in fact used pectins extracted from roots of this species, containing more than 33% of galacturonic acid, to synthesize a library of 5 Se-Ps. Yields were in the range 40.6%–53.0% and Se contents from 3.24 mg /g to 13.2 mg /g. The anti-oxidant capacities of the obtained Se-Ps were assessed by the total reducing power test, and nitrite, SOD-like, hydroxyl, and DPPH radicals scavenging activities. The presence of Se in pectic polysaccharides greatly enhanced the reducing power respect to the native polymer in a dose-dependent manner. A parallelism between the Se content of pectins and nitrite scavenging capacities was observed. The Se-P featured by the highest content of Se at the highest concentration applied (2 mg / mL) performed the best scavenging effect towards nitrite anion 2-fold respect the native polysaccharide. Such great differences on the contrary were not appreciably noted for the SOD-like effects and hydroxyl and DPPH radicals scavenging properties.