Reactive oxygen |
Symbol |
Half life (in sec) |
Reactivity / Remarks |
Superoxide |
O2• |
0- 6 s |
Generated in mitochondria, in cardiovascular system and others |
Hydroxyl radical |
•OH |
10-9 s |
Very highly reactive, generated during iron overload and such conditions in our body |
Hydrogen peroxide |
H2O2 |
stable |
Formed in our body by large number of reactions and yields potent species like OH |
Peroxyl radical |
ROO• |
s |
Reactive and formed from lipids, proteins, DNA, sugars etc. during oxidative damage |
Organic hydro peroxide |
ROOH |
stable |
Reacts with transient metal ions to yield reactive species |
Singlet oxygen |
1O2 |
10-6 s |
Highly reactive, formed during photosensitization and chemical reactions |
Ozone |
O3 |
s |
Present as an atmospheric pollutant, can react with various molecules, yielding 1O2 |
