Reactive Oxygen Species (ROS) are highly reactive molecules, including free radicals (like the superoxide anion) and non-radical species (such as hydrogen peroxide). They are naturally produced during cellular processes like energy production in mitochondria, but can also come from external sources like pollution or smoking, and their levels can be influenced by our diet. When present in high amounts, ROS can damage cells, proteins, and DNA.
Antioxidants are substances that help neutralize ROS, preventing cellular damage. They include enzymes (such as superoxide dismutase) and vitamins (like vitamin C and E).
In simple chemistry, oxidation means losing electrons while reduction means gaining electrons — together, these opposing processes create a balance called redox potential, which indicates how oxidized or reduced a system is.
The careful balance between ROS and antioxidants is crucial for maintaining cellular health. When this balance is disrupted, it can lead to stress conditions in the cell:
- Oxidative stress occurs when there is an excess of ROS compared to antioxidants, resulting in damage to proteins, lipids, and DNA.
- On the other hand, reductive stress arises when there are too many antioxidants relative to ROS, which can also cause damage and interfere with normal cellular functions.