Ginger (Zingiber officinale) is a flowering plant in the family Zingiberaceae whose rhizome, ginger root or simply ginger, is widely used as a spice or a medicine. It is a herbaceous perennial which grows annual stems about a meter tall bearing narrow green leaves and yellow flowers. Ginger is indigenous to southern China, and was spread eventually to the Spice Islands, other parts of Asia and subsequently to West Africa and the Caribbean. Ginger was exported to Europe via India in the first century AD as a result of the lucrative spice trade. India remains the largest producer of ginger.
Other members of the family Zingiberaceae include turmeric, cardamom and galangal. The distantly related dicots in the genus Asarum are commonly called wild ginger because of their similar taste.
The characteristic odor and flavor of ginger is caused by a mixture of zingerone, shogaols and gingerols, volatile oils that compose one to three percent of the weight of fresh ginger. In laboratory animals, the gingerols increase the motility of the gastrointestinal tract and have analgesic, sedative, antipyretic and antibacterial properties. A study at the University of Michigan demonstrated that gingerols can inhibit growth of ovarian cancer cells in vitro. [6]-gingerol (1-[4'-hydroxy-3'-methoxyphenyl]-5-hydroxy-3-decanone) is the major pungent principle of ginger.
Ginger contains up to three percent of a fragrant essential oil whose main constituents are sesquiterpenoids, with (?)-zingiberene as the main component. Smaller amounts of other sesquiterpenoids (?-sesquiphellandrene, bisabolene and farnesene) and a small monoterpenoid fraction (?-phelladrene, cineol, and citral) have also been identified. [Source: Wikipedia]
ORAC Source
USDA Database for the Oxygen Radical Absorbance Capacity (ORAC) of Selected Foods, Release 2 - Prepared by Nutrient Data Laboratory, Beltsville Human Nutrition Research Center (BHNRC), Agricultural Research Service (ARS), U.S. Department of Agriculture (USDA) - May 2010