Possible Interaction: Hydrogen Peroxide and Ascorbate

“The anti-cancer effects of ascorbate are hypothesized to involve the autoxidation of ascorbate leading to increased steady-state levels of H2O2 ; however, the mechanism(s) for cancer cell-selective toxicity remain unknown.”

“ Ascorbate administration selectively diminished apheresis-enhanced H2O2 and inflammatory mediators such as tumor necrosis factor alpha (TNF-&agr;) and monocyte chemoattractant protein-1.”

“Pharmacological doses of ascorbate selectively induce cell death in different types of cancer cells through the generation of H2O2.”

“ Ascorbate‐generated H2O2 damages DNA, activates PARP, depletes NAD+ and ATP.In the absence of PARP activation, cell death is mediated by ROS‐induced DNA damage.”

“Cells that were exposed to hydrogen peroxide (H2O2) for 3 hours, exhibited increases in several histone methylation marks including H3K4me3 and decreases of histone acetylation marks including H3K9ac and H4K8ac; pre-incubation with ascorbate attenuated these changes.”

“At these pharmacological levels, and in the presence of catalytic metal ions, ascorbate can induce oxidative stress through the generation of hydrogen peroxide (H2O2).”

“ Brief hydrogen peroxide treatment or incubation in an enriched oxygen atmosphere led to a marked further reduction of ISCU protein levels, which could be prevented by pretreatment with the antioxidant ascorbate.”

“Results: There was a time- and dose-dependent increase in measured H2O2 production with increased concentrations of ascorbate.”

“It has been postulated that the presence of ascorbate in AqH can contribute to increased photoproduction of H2O2 mediated by the iris melanin.”

“Our data show that exogenous ascorbate significantly amplified the rate of H2O2 photoformation in all melanotic samples.”

“We postulate that also in vivo ascorbate increases the rate of iris melanin‐mediated photoformation of H2O2 and its steady state concentration in AqH.”

“On the other hand, cells such as HL-60, which showed growth inhibition at higher concentrations of ascorbate in medium among observed cells, were damaged by the exposure to higher concentrations of hydrogen peroxide (H2O2).”