Antioxidant
“A substance that protects cells from the damage caused by free radicals (unstable molecules made by the process of oxidation during normal metabolism). Free radicals may play a part in cancer, heart disease, stroke, and other diseases of aging. Antioxidants include beta-carotene, lycopene, vitamins A, C, and E, and other natural and manufactured substances.”
Source:
The National Cancer Institute
https://www.cancer.gov/publications/dictionaries/cancer-terms/def/antioxidant