Selective Lipophilization\nof Natural Phenolic Alcohols\nInduced by <i>In Situ</i> Choline Chloride-Based Natural\nDeep Eutectic Solvents

In this scientific work, a novel and green method for\nselective\nlipophilization of EVOO’s bioactive phenolic alcohols (PAs),\nnamely, tyrosol, hydroxytyrosol, and its metabolite homovanillyl alcohol\nas fatty acid esters, is elucidated. The PAs have been employed as\nhydrogen bond donors in the formation of natural deep eutectic solvents\n(NADES) with choline chloride (ChCl). The fast and cheap esterification\nmethod by <i>in situ</i> formation of choline chloride-based\ndeep eutectic solvents promotes the derivatization of PAs with various\nfatty acids as acylating agents in the absence of organic solvents\nand catalysts. Furthermore, given the growing interest in the application\nof NADES formed by bioactive molecules in the pharmacological and\ncosmetic fields, we analyzed the activity of antioxidant enzymes,\nsuperoxide dismutase, and glutathione S-transferase of three chemical\nformulations obtained after the formation of PA-oleate in the H<sub>2</sub>O<sub>2</sub>-treated HaCat human keratinocytes cell line,\nassessing also their toxicity via the MTT assay.