Pterodon emarginatus Hydroalcoholic Extract: Antioxidant and Photoprotective Activities, Noncytotoxic Effect, and Perspective of Obtaining Formulations with Photochemoprotective Activity

Objective: This study aims to investigate the antioxidant and photoprotective activities and cytotoxicity effect of hydroalcoholic extract of P. emarginatus (HEP) and obtain formulations with photochemoprotective activity containing HEP in Lanette®, Polawax®, or Focus Gel®. Materials and Methods: Phenolic compounds, antioxidant activity, cytotoxic effect, and in vitro sun protection factor (SPF) were determined in HEP. Lanette®, Polawax®, or Focus Gel® containing HEP or synthetic sunscreen (Eusolex 2292®) or both Eusolex 2292® and HEP were prepared. The in vitro SPF of the formulations was determined to investigate the association of protection between HEP and synthetic sunscreen. Preliminary stability of formulations was evaluated. Results: Phenolic acids and flavonoids were detected by thin‑layer chromatography. HEP showed antioxidant activity by 2,2‑diphenyl‑1‑picrylhydrazyl, with EC50 of 19.3 µg/mL, and by ferric reducing antioxidant power methods, in which 1 g of the extract reduces 14,880 µM/L of ferrous sulfate. In cytotoxicity assays, an IC50 of 767.3 μg/mL was obtained, suggesting that the HEP is not cytotoxic. The SPF for HEP was 8 ± 0.31 and it was noted an additive effect to SPF for synthetic sunscreen used, in the three formulations, when associated to HEP, resulting in an improvement of about 24% (Focus Gel®), 65% (Lanette®), and 66% (Polawax®). Only on Lanette®‑based formulation, no significant changes of the analyzed parameters were observed during the preliminary stability. Conclusion: It can be suggested that HEP, due to its antioxidant and photoprotective activities, leads to the photochemoprotective effect on the formulations.