Photoprotection by Punica granatum seed oil nanoemulsion entrapping polyphenol-rich ethyl acetate fraction against UVB-induced DNA damage in human keratinocyte (HaCaT) cell line

There has been an increase in the use of botanicals as skin photoprotective agents. Pomegranate (Punica granatum L.) is well known for its high concentration of polyphenolic compounds and for its antioxidant and anti-inflammatory properties. The aim of this study was to analyze the photoprotection provided by P. granatum seed oil nanoemulsion entrapping the polyphenol-rich ethyl acetate fraction against UVB-induced DNA damage in the keratinocyte HaCaT cell line. For this purpose, HaCaT cells were pretreated for 1 h with nanoemulsions in a serum-free medium and then irradiated with UVB (90-200 mJ/cm(2)) rays. Fluorescence microscopy analysis provided information about the cellular internalization of the nanodroplets. We also determined the in vitro SPE of the nanoemulsions and evaluated their phototoxicity using the 3T3 Neutral Red Uptake Phototoxicity Test. The nanoemulsions were able to protect the cells' DNA against UVB-induced damage in a concentration dependent manner. Nanodroplets were internalized by the cells but a higher proportion was detected along the cell membrane. The SPE obtained (similar to 25) depended on the concentration of the ethyl acetate fraction and pomegranate seed oil in the nanoemulsion. The photoprotective formulations were classified as non-phototoxic. In conclusion, nanoemulsions entrapping the polyphenol-rich ethyl acetate fraction show potential for use as a sunscreen product. (C) 2015 Elsevier B.V. All rights reserved.