Radicals are atoms or molecules that have an unpaired electron. When radicals interact with other molecules, they can cause chemical reactions that can lead to the formation of new radicals. Radicals are important in many areas of chemistry, including organic synthesis, polymerization, and atmospheric chemistry. They can also be dangerous, as they can cause oxidative stress and cell damage.
Radicals are formed when atoms or molecules gain or lose electrons. Atoms or molecules that have lost an electron are called oxidizing agents, while those that have gained an electron are called reducing agents. In general, radicals are more reactive than the atoms or molecules from which they were formed. This is because radicals have unpaired electrons, which makes them unstable and highly reactive.
There are many different types of radicals, including hydroxy radicals, nitric oxide radicals, and superoxide radicals. Hydroxy radicals are formed when water molecules (H2O) split into hydroxyl ions (OH-) and hydrogen ions (H+). Nitric oxide radicals (NO) are produced during combustion reactions involving nitrogen-containing compounds such as gasoline. Superoxide radicals (O2-) are produced by the metabolism of oxygen in cells.
Radicals can be damaging to cells and tissues due to their reactivity. For example, hydroxy radical scavengers such as vitamin C help protect cells from damage caused by these reactive oxygen species (ROS). ROS can cause oxidative stress and cell death through a process known as apoptosis. antioxidants such as vitamin E may also help protect cells from damage caused by ROS by scavenging these harmful particles before they cause harm .