Antioxidative activities of water extract and ethanol extract from field horsetail (tsukushi) Equisetum arvense L

Water extract and ethanol extract from top and body portions of field horsetail (tsukushi) were prepared, and the antioxidative activity was investigated using four different methods. The contents of total phenolic components were richer in the ethanol extract fractions of each portion than in the water extracts. On the other hand, protein contents were much lower in ethanol extract fractions than in water extract fractions. These fractions had remarkable antioxidative activities, similar to that of 5 mM ascorbic acid. Water extracts of both portions showed high superoxide anion radical-scavenging activities. Hydroxyl radicals were effectively scavenged by ethanol extracts. Field horsetail (tsukushi) is rich in vitamins C and E. Moreover, it contains high levels of copper and zinc. These are essential elements, for superoxide dismutase to act against active oxygen species. Tsukushi is not only a health food, but is also useful in preventing various degenerative diseases.