Oxidative Stress, Prooxidants, and Antioxidants: The Interplay
Table 3
Different classes of prooxidants and their common mechanism for development of oxidative stress.
Sl. number
Class
Examples
Mechanism
(1)
Drugs
Common over-the-counter drug like analgesic (paracetamol) or anticancerous drug (methotrexate)
ROS generation leading to alterations in macromolecules which finally can fatally damage the tissues mainly liver and kidney
(2)
Transition metals
Magnesium, iron, copper, zinc, and so forth
These metals induce Fenton reaction and Haber-Weiss reaction leading to generation of excessive ROS. Chronic magnesium is a classic prooxidant disease. The other can be hemochromatosis due to high iron levels or Wilson disease due to copper
(3)
Pesticide
BHC, DDT, and so forth
Stimulation of free radical production, induction of lipid peroxidation, alterations in antioxidant enzymes and the glutathione redox system
(4)
Physical exercise
Running, weight lifting
Relaxationcontraction of muscle involves production of ROS. Rigorous exercise leads to excessive ROS
(5)
Mental anxiety
Tension, apprehension
Imbalance in the redox system plays a role in neuroinflammation and neurodegeneration, mitochondrial dysfunction, altered neuronal signaling, and inhibition of neurogenesis
(6)
Pathophysiology
Local ischemia
Gives rise to increased ROS generation
(7)
Environmental factor
Extreme weather (heat, cold, thunderstorm)
During adaptation, mitochondrial membrane fluidity decreases which may disrupt the transfer of electrons, thereby increasing the production of ROS
(8)
Antioxidants
Ascorbic acid, vitamin E, polyphenols
Act as prooxidant under certain circumstances, for example, heavy metals
