Hydrogen Peroxide. Ubiquitous in Cell Culture and In vivo?

Abstract

Hydrogen peroxide (H2O2) is widely regarded as a cytotoxic agent whose levels must be minimized by the action of antioxidant defence enzymes. In fact, H2O2 is poorly reactive in the absence of transition metal ions. Exposure of certain human tissues to H2O2 may be greater than is commonly supposed; levels of H2O2 in the human body may be controlled not only by catabolism but also by excretion, and H2O2 could play a role in the regulation of renal function and as an antibacterial agent in the urine. Cell culture is a widely used method for the investigation of "physiological" processes such as signal transduction and regulation of gene expression, but chemical reactions involving cell culture media are rarely considered. Addition of reducing agents to commonly used cell-culture media can lead to generation of substantial amounts of H2O2. Some or all of the reported effects of ascorbic acid and polyphenolic compounds (e.g., quercetin, catechin, epigallocatechin, epigallocatechin gallate) on cells in culture may be due to H2O2 generation by interaction of these compounds with cell culture media.

Effects of Uptake of Flavonoids on Oxidative Stress Induced by Hydrogen Peroxide in Human Intestinal Caco-2 Cells

“…7) On the other hand, the pro-oxidative effects and cytotoxicity of flavonoids, possibly due to generation of ROS, including H 2 O 2 , and induction of apoptosis have been reported. [8][9][10] Thus flavonoids appear to have both antioxidative and pro-oxidative effects, but clear evidence of prevention of oxidative stress by the antioxidative activity of flavonoids is lacking. Hence, we studied their activity using a cell culture system.…”

A Natural Formulation Increases Brain Resistance to Oxidative Stress

“…We cannot exclude that the beneficial effects of Illumina ® , in vivo, could be the consequence of adaptative stress responses to moderate levels of hydrogen peroxide. It is well known that antioxidants in the liquids could exert pro-oxidative effects, by generating hydrogen peroxide and thus activating adaptative responses of cells to mild oxidative stress [27]. MTT test revealed no significant effects of extracts on cell viability up to 100 μg/ml (data not shown).…”

Polyphenol Ellagic Acid-Targeting To Brain: A Hidden Treasure

“…H2O2 is generated by almost all sources of oxidative stress. DNA is damaged by H2O2 via fenton reaction in presence of oxygen and transition metal ions [76,77] . During neurodegenerative diseases, the various oxidative reactions involved that leads to neuronal cell death [78] .…”