Natural products have been used to protect the skin from harmful UV radiation for decades. Recent research has focused on discovering novel UV absorbing photoprotective molecules from nature. In response to the excessive damage caused by UVB rays, plants induce the production of high concentrations of phytoprotective secondary metabolites and anti-oxidative enzymes. Despite promising UV absorbing and photoprotective properties, plant secondary metabolites have been underutilized in topical delivery – due to low solubility and high instability. Recently, numerous phytochemicals have been effectively nanosized, incorporated in formulations and studied for their sustained effects in photoprotection.

The purpose of a new study published in Environment Science and Pollution Research International was to outline developments in nanosizing and delivering photoprotective crude plant extract and phytochemicals from a phytochemical perspective.

This review entailed search for articles using keywords – "UV damage", "skin photoprotection", "photodamage" and "nano delivery" in varied combinations. Literature from 43 original research articles was identified and reviewed, exploring nanosized phytochemicals and crude plant extracts with photoprotective activity.

The results revealed that nanosized phytochemicals retained higher amounts of bioactive compounds in the skin and acted as depots for their sustained release. In addition, novel approaches in nanosizing considerably improved the photostability, efficacy and water resistance of plant secondary metabolites.

It was concluded that current findings can be useful in devising broad-spectrum sunscreen products in the future.

Source: Environment Science and Pollution Research International. 2020 Aug 6. doi: 10.1007/s11356-020-10100-y.