Antioxidants (or anti-oxidation agents) are substance that protect body cells from the damage caused by oxidation from free radicals (free oxygen radicals).
Antioxidants scavenge free radicals from our body cells by binding to free radicals, decreasing the free radicals destructive power. Antioxidants neutralize free radicals by donating one of their own electrons, breaking the electron-stealing chain reaction. The antioxidant themselves do not become free radicals by donating an electron because they are stable in either form.
Antioxidants act like scavengers, preventing cell damage. Antioxidants can also help repair damage already sustained by cells.