Which of the following is NOT an anti oxidant?

Serum, tissue fluids, and host cells possess antioxidant mechanisms that protect against these potentially harmful oxygen-derived radicals. They include (1) the enzyme superoxide dismutase, which is found in or can be activated in a variety of cell types; (2) the enzyme catalase, which detoxifies H2O2; (3) glutathione peroxidase, another powerful H2O2 detoxifier; (4) the copper-containing serum protein ceruloplasmin; and (5) the iron-free fraction of serum transferrin. Thus, the influence of oxygen-derived free radicals in any given inflammatory reaction depends on the balance between production and inactivation of these metabolites by cells and tissues. Ref: Robbins 8th edition, Chapter 2.