Radishes are rarely labeled a superfood but if you compare their ORAC value to fresh kale you will see they are both around 1,700. When eating radishes, to get the most nutrition be sure and eat their bright red skin, as that is where much of the antioxidants are located.
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