Antioxidants in Cellular Defense: FromBiological Mechanisms to Plant-BasedTherapeutic Applications

Abstract

Background: Free radicals are unstable atoms possessing one or more unpaired electrons, making them highly
reactive. They, along with other reactive species, are collectively termed Reactive Oxygen Species (ROS) and
Reactive Nitrogen Species (RNS). While they are involved in normal biological processes, their excessive
accumulation leads to oxidative stress, which is associated with the development of various diseases. Aim: To
review the role of antioxidants in neutralizing free radicals and their significance in preventing oxidative stressrelated diseases. Methodology: A comprehensive literature review was conducted focusing on the classification, mechanisms, and sources of antioxidants, including enzymatic, non-enzymatic, and metal-binding proteins, as
well as plant-derived compounds. Results: The human body possesses intrinsic antioxidant defense systems that stabilize free radicals by donating electrons or hydrogen atoms, thereby preventing cellular damage. These antioxidants act as “free radical scavengers” and include both endogenous and dietary sources. Plantbased antioxidants demonstrated effective free radical quenching activity with minimal side effects compared to synthetic drugs, offering significant protection against oxidative damage. Conclusion: Antioxidants play a vital
role in maintaining cellular homeostasis and preventing oxidative stress-related disorders. Natural, plant-derived antioxidants represent a safe and promising approach for disease prevention and therapeutic applications.