Characterizing the Mechanism of Action of Essential Oils on Skin Homeostasis—Data from Sonographic Imaging, Epidermal Water Dynamics, and Skin Biomechanics

Sérgio Faloni De Andrade,Patricia Rijo,Clemente Rocha,Lin Zhu,Luis Monteiro Rodrigues

doi:10.3390/cosmetics8020036

Sérgio Faloni De Andrade, Patricia Rijo + Show 3 more

Open Access

https://doi.org/10.3390/cosmetics8020036

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Abstract

Essential oils (EOs) have been recognized as materials of interest for dermatological applications, although some doubts remain regarding their safety and efficacy. We studied the action mechanisms of EOs from lavender and sage in human skin. Extracted EOs were incorporated (at 5% and 10%) in almond oil as a vehicle. Eleven healthy volunteers were selected and the prepared oils were tested on both forearms. All procedures respected the principles of good clinical practice. Effects were followed through high resolution sonography (HRS), epidermal water dynamics, and biomechanics. All variables were measured before and 30 min after application. Nonparametric statistical comparisons were applied (p < 0.05). HRS revealed a more echogenic epidermis, with a significant echogenicity decrease in the dermis (higher water retention) for all formulations. Significant TEWL decrease and an increase in superficial and deep epidermal hydration were also observed. These results indicate that EOs penetrate only into the most superficial layers of the skin, which is important for their safety profile. Furthermore, this “filmogenic” mechanism improving the epidermal water balance seems to connect directly with the observed biomechanical enhancement. These results confirm the clinical relevance of these compounds, in particular to restore the epidermal water content and prevent xerosis and other related disorders in sensitive (atopic, elderly) patients.

Highlights

Essential oils are complex mixtures of volatile low molecular weight compounds responsible for the characteristic aroma of each plant
Several essential oils and related lipidic compounds have been incorporated into nanostructured systems for the preparation of over-the-counter formulations for many different purposes [5]
The preliminary safety screen revealed a complete absence of skin reactions and an excellent tolerance to the diluted Essential oils (EOs) as tested

Summary

Introduction

Essential oils are complex mixtures of volatile low molecular weight compounds (monoterpenes and sesquiterpenes) responsible for the characteristic aroma of each plant. Some of these complex organic combinations, extracted by aqueous distillation, have attracted attention from the industry (from chemical, perfume and cosmetics to food) where these oils are already used for their aromatic properties. More recent interest from the pharmaceutical industry is due to scientific studies reporting a wide potential of beneficial activities, including antioxidant, antimicrobial, anti-inflammatory, and even anti-neoplastic properties [1,2,3,4].

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