An example of a preventive antioxidant is:

Antioxidants fall into two classes: Preventive antioxidants, which reduce the rate of chain initiation.  ex: Catalase and other peroxidases such as glutathione peroxidase. Chain-breaking antioxidants, which interfere with chain propagation.  ex: Superoxide Dismutase, Uric Acid, Vitamin E (Most powerful). Key Concept: Catalase falls into preventive anti-oxidants which reduce the rate of chain initiation. Ref : Harper’s illustrated biochemistry, 31st edition.