Many are surprised to see that the ORAC value of fresh raw artichokes is approximately 1/3 less than boiled. The reason for this is because the fresh versions contain more water. After they are cooked, less water remains and therefore, the antioxidant content (as well as all other nutrition) is more concentrated.
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