A new article published in Molecules discussed that direct sun exposure is one of the most aggressive factors for human skin pigmentation. Sun radiation contains a range of the electromagnetic spectrum including UV light; the stratospheric ozone layer filters the most harmful UVC. It is known that the human skin contains a photoprotective pigment called melanin to protect from UVB, UVA and blue visible light. The authors reported that this pigment is a redox UV-absorbing agent and functions as a shield to prevent direct UV action on the DNA of epidermal cells.

Melanin indirectly scavenges reactive oxygenated species (ROS) formed during the UV-inducing oxidative stress on the skin. In most phenotypes, endogenous melanin is not adequate for a complete protection, particularly during summers. Hence, photoprotective molecules should be added to commercial sunscreens.

The article elaborated that photoprotective molecules are said to exhibit UV-absorbing capacity to complement the intrinsic photoprotection of cutaneous natural pigment. These agents have antioxidant properties – this feature is usually marketed to be imparting a skin-lightening effect. On the contrary, good photoprotectors should be able to enhance the natural cutaneous pigmentation. Flavonoids are photoprotective molecules, that are derived from plant extracts and stimulate melanogenesis. However, the correlation between different flavonoid structures and melanin stimulation has not been defined.

Source: Molecules. 2020 Mar 27;25(7):E1537. doi: 10.3390/molecules25071537.