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

Abstract

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.

Keywords: Additive effect of sun protection; antioxidant activity; natural product; phytocosmetic; sun protection factor