Natural products and extracts from plants as natural UV filters for sunscreens: A review

Although solar exposure is necessary for human health, phototoxicology induced by excessive UVB and UVA radiation, which involves sunburns, skin aging and even tumorigenesis, has been widely researched. Sunscreen is one of the most important ways to protect skin from UV phototoxic damage. As well as inorganic and organic UV filters, some natural products or plant extracts with aromatic rings in their structures, such as flavonoids or polyphenols, can absorb UV to reduce sunburn, acting as a natural UV filter; they also show antioxidant or/and anti-inflammatory activity. This could explain why, although there are no officially approval natural commercial sun-filters, more and more commercial sunscreen products containing plant extracts are available on the market. Here we summarize articles focusing on natural UV filters from plant published in the last 6 years, selecting the most significant data in order to better understand the photoprotective activity of natural products and extracts from plants, including their major constituents and main biological effects, methods for evaluating UV radiation resistance, anti-UV radiation experimental models and anti-UV radiation mechanisms.