Potential natural antioxidants from Saskatchewan indigenous plants

Ethanolic extracts from echinacea (Echinacea angustifolia) root, senega (Polygala senega) root, wild licorice (Glycyrrhiza lepidota) root, bearberry (Arctostaphylos uva-ursi) leaves and aerial parts of horsetail (Equisetum spp.) were evaluated for their antioxidative activity using a beta-carotene-linoleate model system. The extract of bearberry exhibited the highest activity, followed by those of wild licorice, senega, echinacea and horsetail. Phenolic compounds proved to be, at least in part, responsible for the observed antioxidative activity. The multistep fractionation of the most promising extract (i.e., bearberry) by column chromatography yielded seven fractions, of which some exhibited an antioxidative efficacy equivalent to that of butylated hydroxyanisole. Isolation and structural characterization of constituents from the bearberry have been pursued.