Main content area

Studies on the antioxidant activity of Echinacea root extract

Hu, C., Kitts, D.D.
Journal of agricultural and food chemistry 2000 v.48 no.5 pp. 1466-1472
Echinacea, Echinacea purpurea, Echinacea angustifolia, roots, plant extracts, oxidation, chemical reactions, free radicals, lipids, lipid peroxidation, low density lipoprotein, humans, phenolic acids, chlorogenic acid, caffeic acid, free radical scavengers
Methanol extracts of freeze-dried Echinacea (E. angustifolia, E. pallida, and E. purpurea) roots were examined for free radical scavenging capacities and antioxidant activities. Root extracts of E. angustifolia, E. pallida, and E. purpurea were capable of scavenging hydroxyl radical. Similar scavenging activities for each variety were found for both 1,1-diphenyl-2-picrylhydrazyl radical and ABTS radical. Meanwhile, antioxidant activities of all three varieties of Echinacea were found to delay the formation of conjugated diene hydroperoxide induced by the thermal decomposition of 2,2'-azobis(2-amidinopropane) dihydrochloride and extend the lag phase of peroxidation of soybean liposomes. Echinacea root extracts suppressed the oxidation of human low-density lipoprotein, as evaluated by reduced agarose electrophoretic mobility following oxidative modification by Cu2+. The mechanisms of antioxidant activity of extracts derived from Echinacea roots included free radical scavenging and transition metal chelating.