Seasonal variation in phenolics in several savanna tree species in Botswana

Medicinal plants of Cree communities (Québec, Canada): antioxidant activity of plants used to treat type 2 diabetes symptoms

Traditional medicines (TM) used to treat symptoms of diabetes by two Cree communities were assessed for their free radical scavenging activity using the stable 1,1-diphenyl-2-picrylhydrazyl radical, and their ability to protect human low-density lipoprotein from Cu2+-mediated oxidation by measuring lag time before the appearance of conjugated dienes and formation of thiobarbituric acid-reactive substances. Water-soluble phenolic content was also measured. A total of 20 medicinal plants from Whapmagoostui and 16 from Mistissini were compared with 16 extracts of plants that were not used medicinally. Medicinal plant extracts, particularly those from Larix laricina, displayed high antioxidant activity, comparable with ascorbic acid, Trolox, and the known antioxidant flavonoids quercetin, epicatechin, catechin. Extracts of Pinaceae and Ericaceae contained the highest levels of phenolics. Factors such as season and area of plant collection, as well as the plant part from which the extract was derived, affected antioxidant activity. Positive correlations were found between the established traditional knowledge of Cree Elders and Healers and the antioxidant activity for medicinal plants used in Mistissini (r = 0.3134; p = 0.058) and in Whapmagoostui (r = 0.5165; p = 0.001). Significant correlations between phenolic content were also seen with the existing ethnobotanical data (r = 0.5015; p = 0.003) and bioassays (r = 0.4178; p = 0.003). These results indicate that a clear majority of plants used by the Cree are excellent sources of antioxidants.

Saponins and phenolic content in plant dietary additives of a traditional subsistence community, the Batemi of Ngorongoro District, Tanzania

Reports of plants added to milk and meat-based soups by the Maasai and Batemi in East Africa support a role for phenolic antioxidants and hypocholesterolemic agents in the diet, and provide explanation of the low incidence of cardiovascular disease of populations that traditionally consume high levels of dietary fat and cholesterol. Plant food additives used by the Batemi of Ngorongoro District, Tanzania, were tabulated, based on interviews with 22 informants, while 17 specimens were collected in the field and analyzed for saponin and phenolic content. A total of 81% of the Batemi additives and 82% of those known to be used by the Maasai contain potentially hypocholesterolemic saponins and/or phenolics.