An ORAC test for raw and fresh lima beans hasn't been done, so we don't know how much antioxidant activity is lost in the canning process. What we can conclude though is that the canned version definitely doesn't have much antioxidant content.
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