Said M. Al-Dalaen

Abstract: Oxidative stress is a phenomenon that reflects an imbalance between the production of reactive oxygen species and so-called oxidants, and their elimination by protective mechanisms. These are referred to as antioxidative systems which can detoxify the reactive intermediates, or repair the resulting damage causing toxic effects through the production of peroxides and free radicals that damage all cell components. Further, some reactive oxidative species act as cellular messengers in redox signaling that can cause disruptions in normal cellular signaling mechanisms. In humans, oxidative stress is thought to be involved in the development of atherosclerosis, neurodegenerative diseases, such as Alzheimer’s and Parkinson’s disease, cancer, diabetes mellitus, inflammatory diseases, as well as psychological diseases or aging processes. It is presently accepted that the reactive oxygen species can be beneficial. Depending on the type of oxidants, intensity and time of redox imbalance, as well as on the type of cells, oxidative stress can play a role in the regulation of other important processes. This is achieved through modulation of signal pathways, influencing synthesis of antioxidant enzymes, repair processes, inflammation, or via the immune system, as a way to attack and kill pathogens. This limits the potential for apoptosis and cell proliferation, and thu