Cecropia obtusa, an Amazonian ethanolic extract, exhibits photochemoprotective effect in vitro and balances the redox cellular state in response to UV radiation

By Georgia de Assis Dias Alves - Rebeca Oliveira de Souza - Hervé Rogez - Hitoshi Masaki - Maria José Vieira Fonseca

In order to exhibit photochemoprotective effect a cosmetic formulation is supposed to display both the ability to absorb UVA/UVB radiation and exhibit a biological effect to protect the skin against the damage caused by the radiation. Because animal tests are no longer acceptable for cosmetic development, the present study evaluated the photochemoprotective potential of Cecropia obtusa leaf extract against UVA-induced damage in keratinocytes and explored, in detail, the antioxidant capacity using in vitro systems. The extract exhibited a high antioxidant capacity, particularly towards superoxide radical and singlet oxygen. The EC50 values for DPPH, superoxide radical and singlet oxygen were 1.63μg/mL, 0.34μg/mL and 0.55μg/mL, respectively. In addition, the total polyphenol content and total flavonoid content were 371.5mg of gallic acid equivalent/g and 66.68mg of quercetin equivalent/g, respectively. Through the cell model, the extract was able to protect the UVA radiation-induced damage. For lipid peroxidation and superoxide dismutase activity, the group that was treated for 24h and irradiated in the absence of the extract exhibited better protection than the group that underwent the same treatment and was irradiated in the presence of the extract. The opposite pattern was observed for the reduced glutathione levels, catalase activity and reactive oxygen species formation. In addition to protecting keratinocytes from UVA-induced damage and balancing the redox cellular state, the extract was also capable of absorbing UV radiation. Therefore, the C. obtusa extract would be able to improve the absorption spectrum of formulations containing UV filters and provide a biological effect by protecting against oxidative damage.