Ginger is a widely researched spiced, have been evaluated for possible anti-cancer and anti-inflammatory properties in medical studies. As far as how much antioxidants this root vegetable has, it's fairly high.
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