Solar uv damage and skin protection:the boosting of natural defences and healing by cosmeceuticals

The electromagnetic spectrum of solar radiations has been divided into the UVC region(below 290 nm, not incident on the earth’s surface) and the UVB (290-320 nm) and UVA (320-400 nm) regions. Wavelengths below 290 nm are blocked by the stratosphericozone layer. Both UVA and UVB radiations cause damage to skin cells and skin tissue and these events have been linked to acute damage such as sunburn as well as the chronic occurrence of skin cancer and inevitable photoaging. UVA generates distinct types of damage often associated with oxidative stress which is mediated by reactive oxygen species (ROS). UVA also elicits quite distinct stress pathways. The oxidisingnature of the interaction of UVA radiation with human skin cells and the implications of this for endogenous and exogenous antioxidant defence will be considered in this overview.