antioxidant

n. substance that inhibits oxidation

An Antioxidant is a molecule capable of slowing or preventing the oxidation of other molecules. Oxidation is a chemical reaction that transfers electrons from a substance to an oxidizing agent. Oxidation reactions can produce free radicals, which start chain reactions that damage cells. Antioxidants terminate these chain reactions by removing free radical intermediates, and inhibit other oxidation reactions by being oxidized themselves. As a result, antioxidants are often reducing agents such as thiols or polyphenols.
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Antioxidant /an·ti·ox·i·dant/ something added to a product to prevent or delay its deterioration by the oxygen in air. an·ti·ox·i·dant n. 1. [more]Antioxidant - Community and Resources

Noun
1. substance that inhibits oxidation or inhibits reactions promoted by oxygen or peroxides
(hypernym) inhibitor
(hyponym) glutathione peroxidase

n. antioxidant, substance that inhibits oxidation