NADES-in-Oil Emulsions Enriched with Essential Oils for Cosmetic Application

Abstract

This research aims to explore the potential benefits of natural deep eutectic solvents (NADES) in formulating translucent NADES-in-oil emulsions (TEs) containing essential oils (EOs) for cosmetic applications. The TEs investigated in this study are based on previous formulations, consisting of 50 wt.% egg phosphatidylcholine (EPC), 20 wt.% ethanol, 20 wt.% olive oil (OlO), thyme oil (TO), or oregano oil (OrO), and 10 wt.% NADES made from a 1:1 or 1:4 ratio of lactic acid and glycerol (LA). These emulsions exhibit high antioxidant activity, attributed to the terpenes present in the essential oils, such as thymol in TO and carvacrol in OrO. The TEs containing TO and OrO demonstrated a more fluid consistency, along with a more appealing texture and fragrance compared to the OlO control. Additionally, these emulsions exhibited the ability to permeate pig skin, as well as significant antifungal and antibacterial activity, and low toxicity in the Galleria mellonella larval model. Overall, the findings expand the potential applications of NADES, particularly in the development of translucent emulsions with EO for treating microbial skin and nail infections.