UV- Generated Free Radicals (FR) in Skin and Hair – Their Formation, Action, Elimination and Prevention A General View

Solar UV exposure is one of the most im-portant factors that leads also to photo ageing and photo damage of the hair. S kin and hair are the direct target organs of sun radiation, of electro-magnetic waves with wavelengths between 1000nm and 280 nm. The wavelength determines the penetration depth into the target ob-ject and the energy of the photon which determines the effect on the mol-ecular structure of the object. The superoxide anion is the primary free radical generated by UV from molecular oxygen. It sets off a chain reaction resulting in further free radical compounds like hydroxyl radicals and fur-ther on to free radicals with intermediate activity which are the most likely species to lead to direct biological damages and numerous pathological changes of the skin. The reduction of the sun incidence is the only way to prevent these damages of skin. A sunscreen is the first defence line to pre