**3. Sources of oxidants in human bodies**

In its entirety, metabolic and respiratory processes in the body initiate the creation of reactive oxygen species (ROS), such as free radicals (O2 \_ ) from superoxide anions, hydroxyl ions, and peroxides (H2O2), including some, which are highly reactive [10] and capable of inducing oxidative ruin to fleshy and corpuscle constituents, such as polypeptides, fats, biomolecules, and nucleic acids, when left unbalanced. Scientists

have demonstrated that oxidative stress exacerbates the likelihood of genesis and development of chronic disease conditions once there is an excessive build-up of large aggregates of ROS.

Production of malondialdehyde (MDA) (a major indicator of lipid oxidation), which is a central ingredient of oxidative stress incriminated in unpleasant health effects explains the negative consequences of the action of oxidants on lipids and fats. In his summary of findings, Rasaei [15] recommends a desperate need for interventions, especially the utilization of green tea to augment the body's antioxidant response to be able to counteract oxidative stress and MDA production.

Throughout human lives, people suffer equilibrium disruptions, thanks to human lifestyles; the food, drinking water, coupled with the composition of the air inhaled [16–25], intense physical exercise [26–31], and stress predisposes the superfluous formation of reactive oxygen species in human bodies. Consequently, ROS contains free radicals that steer the emergence of oxidative stress, which vandalizes the anatomy of the human organism, thereby causing a disruption in body functional equilibrium, thus precipitating disorders, such as hardening of the arteries, lymphoproliferative, and/or neurodegenerative upsets (Parkinson's or Alzheimer's disease), or maybe obesity.

A fundamental hunt for straightforwardly available sources of antioxidants perpetuates the steadiness in the middle of creating and eliminating reactive oxygen species, examples of dominant and massively predominant antioxidants are alphatocopherol (vitamin E), retinol (vitamin A and vitamin C), and also polyphenolic compounds. The attachment to numerous health- effects, including antioxidant validity to phenolic chemicals is based on findings from rigorous research and has positioned phenols as a vital part of the human diet. Polyphenols can proficiently trap oxidizing peroxide ions, and exterminate lipid radicals, ROS, and hydroxyl radicals.

Polyphenols extracted from plants contribute significantly to decelerating senescent progression and decreased contingency of neurodegenerative conditions related to age, such as Alzheimer's disease, Parkinson's disease, and/or ischemic brain trauma. Some of the natural plant resources, tea, coffee, fruits, vegetables, spices, and herbs are rich sources of antioxidants in the form of flavonoids, which supplement the daily menu, adding up to good health [23].
