The "antioxidant" method of many antioxidants is their ability to bind to elements, especially metals, rendering them inert. This has more to do with the benefits of food processing than food digestion as you don't want a canned and left on the shelf for 3 years product having the chain of oxidation kicked off or at least expedited by the circulation of metals many of which are potent pro-oxidants. In the gut however your body is built to use those metals, not the bound compounds.
"You can demonstrate the purpose and limits of human digestion with a simple experiment: eat a steak with some whole corn kernels, and see what comes out the other end. It won’t be the steak."