antioxidant

American  

[an-tee-ok-si-duhnt, an-tahy-] / ˌæn tiˈɒk sɪ dənt, ˌæn taɪ- /

noun

1. Chemistry. any substance that inhibits oxidation, as a substance that inhibits oxidative deterioration of gasoline, rubbers, plastics, soaps, etc.

2. Biochemistry. an enzyme or other organic substance, as vitamin E or beta carotene, that is capable of counteracting the damaging effects of oxidation in animal tissues.

---

adjective

1. Chemistry. of or relating to an antioxidant.

antioxidant British  

/ ˌæntɪˈɒksɪdənt /

noun

1. any substance that retards deterioration by oxidation, esp of fats, oils, foods, petroleum products, or rubber

2. biology a substance, such as vitamin C, vitamin E, or beta carotene, that counteracts the damaging effects of oxidation in a living organism

---

antioxidant Scientific  

/ ăn′tē-ŏk′sĭ-dənt,ăn′tī- /

1. A chemical compound or substance that inhibits oxidation. Certain vitamins, such as vitamin E, are antioxidants and may protect body cells from damage caused by the oxidative effects of free radicals.

---

Etymology

Origin of antioxidant

First recorded in 1925–30; anti- + oxidant ( oxid(ize) + -ant )

Explanation

An antioxidant is a substance that helps prevent damage caused by certain chemical reactions in our bodies. Fruits, vegetables, and beans are full of antioxidants. Vitamins C and E are familiar antioxidants found in foods like spinach, strawberries, kiwifruit, and lima beans. These substances work in two main ways. They sometimes prevent chemical oxygen reactions that produce damaging, unstable free radicals. They can also bind with the free radicals to make them stable and keep them from causing damage. Antioxidants don't just protect our bodies; they are also used to keep food fresh — a squeeze of lemon juice (Vitamin C) on a sliced apple helps prevent oxidation that turns the fruit brown.

Example Sentences

Their study, published in Tropical Plants, found that the cooler temperature slows ripening, preserves fruit structure, and activates the mango's natural antioxidant defenses.

From Science Daily • May 23, 2026

Researchers measured the activity of protective enzymes including APX, SOD, PAL, and POD, while also analyzing gene expression linked to antioxidant defense systems.

From Science Daily • May 23, 2026

"Creatine's anti-inflammatory and antioxidant properties further underscore its promise in clinical settings, though more robust trials are needed to confirm these benefits," he explains.

From Science Daily • May 4, 2026

Phenolic compounds, particularly flavonoids, are already highly valued in medicine for their antioxidant, anti-inflammatory, and anti-carcinogenic effects.

From Science Daily • May 1, 2026

After a minute, Mom said, “I’m taking some classes. Online, through IU. To get my master’s in social work. In fact, I wasn’t looking at antioxidant recipes; I was writing a paper.”

From "The Fault in Our Stars" by John Green