"Active" photoprotection: sunscreens with DNA repair enzymes. A review of the literature

Ultraviolet (UV) radiation exerts different harmful effects on human health, being the main etiological agents of certain skin cancers and photoaging. In this context, photoprotection, intended as a set of measures adopted to limit and prevent the effects of UV radiation, plays a critical role in avoiding undesired sunlight outcomes. Traditional sunscreens represent a widely used photoprotective approach, even if they exert a "passive photoprotection" and are not effective once damage to skin cells has been generated after sun exposure. Conversely, "active" photoprotection is represented by topical sunscreens including also antioxidants and liposome-containing DNA repair enzymes, which may constitute a photostrategy filling the current gap in sun protection. In the current review, we focused on "active" photoprotection at a topical level, reporting present knowledge and future prospective regarding DNA repair enzymes such as photolyase, T4 endonuclease V and 8-oxoguanine glycosylase which are able to enhance the protective power of traditional sunscreens.