Evaluation of Photosensitizing Ability of Antioxidants Used in Skincare Products

Abstract

Singlet oxygen generation is possible by photosensitizer molecules able to absorb energy from light and transfer it to molecular oxygen. Singlet oxygen is able to react with components of cellular membranes such as cholesterol leading to peroxidation products implicated in photoaging. In order to prevent oxidative damage caused by reactive oxygen species, skincare products enriched with antioxidants have been developed; in spite of some pro-oxidant effects associated with antioxidants has been reported. Based on this data, the photosensitizing ability of 14 antioxidants commonly used in skincare products was evaluated through the photo-oxidation of ergosterol, using ergosterol as oxidizable substrate to quench singlet oxygen. Singlet oxygen indirectly detection was performed through1H-NMR mixtures analysis by ergosterol peroxide detection. The results revealed that fisetin, retinol, cyanidin and hesperetin they acted as photosensitizer antioxidants in generation of singlet oxygen. Conversely, caffeic acid, luteolin, rutin, vanillic acid, ascorbic acid, apigenin, epigallocatechin gallate, rosmarinic acid, myricetin and kaempferol were not able to generate singlet oxygen through a photosensitized mechanism. Our results allow us to suggest that the incorporation of antioxidants in skincare products as anti-aging treatments should be supported by their evaluation against photosensitizing ability in order to increase their safety.