Carotenoids are prime examples for antioxidants: they donate electrons to noxious radicals. Density functional calculations anticipate the possibility of electron uptake by carotenoids. This prediction has been confirmed experimentally: carbonyl carotenoids, including the super-antioxidant astaxanthin, easily take up electrons and react as antireductants. (C) 2012 Elsevier Ltd. All rights reserved.