However, as a potent antioxidant, ellagic acid can block melanogenesis by reducing o-quinones and semiquinones
, and quinones," Free Radical Biology and Medicine, vol.
Aminophenol toxicity is related with generation of semiquinones
and superoxide radicals that damage a cell's biomolecules.
Oxygen free radical generating mechanisms in the colon: Do the semiquinones
of vitamin k play a role in the aetiology of colon cancer Biochim.
Oxidation of dopamine and PEA by MAO-B can lead to the production of neurotoxic compounds such as hydrogen peroxide, semiquinones
(Klegeris et al.
Oxidation of catechols to semiquinones
and quinones is a mechanism of tumor initiation not only for endogenous estrogens, but also for synthetic estrogens such as hexestrol and diethylstilbestrol, a human carcinogen.
5] from six cities and found large quantities of radicals with characteristics similar to semiquinones
(Dellinger et al.
The very low levels of nitrogen, sulfur, and oxygen (Table 2) indicate that amines, nitro compounds, oxides of sulfur, quinones, hydroquinones, or semiquinones
are not likely to be the BDS constituents that are primarily responsible for its biologic activity.
As discussed elsewhere [10, 115, 116], the decrease in the number of quenched radicals in the case of quinols might be due to the competition of radical species with oxygen for the semiquinones
of the antioxidant (see (8)).