Antioxidant activity relates to plant part, life form and growing condition in some diabetes remedies

Selection, collection and preparation of 35 plant species used by traditional healers in the boreal regions of Canada for treatment of the symptoms of diabetes were supported empirically by antioxidant activity of the plants. Because antioxidants fluctuate with growth parameters and environmental factors, these remedies were evaluated in relation to the affect of plant part, life form and growing condition on the level of activity. The parts used here more frequently as medicines were roots and bark. Activity (IC 50) of the bark extracts used medicinally averaged to 21.38 ± 3.84 ppm while root extracts used medicinally had an IC 50 of 185.11 ± 32.18 ppm in a free radical DPPH assay. In contrast the analysis of extracts of overall parts (medicinal or not) in these species found leaves and bark to have the least activity (112.22 ± 30.63 ppm and 123.02 ± 21.13 ppm, respectively). The highest activity was found in tree extracts (24.88 ± 3.32 ppm) as compared to herbs and shrubs, and increased activity was found in plant extracts from growing conditions of decreased water/fertility. The antioxidant activity of these traditional plant remedies have the potential to be partially deduced through environment signals interpreted by the traditional herbalist.