Antioxidants play a protective role in biological systems by neutralizing free radicals and preventing oxidative stress. Free radicals are unstable molecules that can damage cellular components such as DNA, proteins, and lipids, leading to various diseases and aging. By donating electrons to free radicals, antioxidants help stabilize these reactive molecules, reducing the risk of cellular damage. Nutrients like vitamins C and E, along with various phytochemicals, act as antioxidants, promoting overall health and wellness by supporting the body's defense mechanisms.