2021 Volume 22 Issue 2 Pages 24-36
Some essential oils used in aromatherapy are known to have antibacterial, anti-inflammatory, and/or antioxidant effects although it has not been scientifically validated. In this study, we screened essential oils with anti-inflammatory effects using an in-vitro inflammation model. Inflammatory cytokines were added to the human epidermal keratinocytes HaCaT to induce the expression of inflammatory and thymus and activation-regulated chemokine (CCL17/TARC). As a result, 7 of the 46 kinds of essential oils, including German chamomile and patchouli, were found to suppress IFN-γ- and TNF-α-induced TARC. Moreover, both essential oils were shown to suppress TARC induction, disregarding the countries of origin and product manufacturers. We also performed RT-PCR to examine the inflammation- and skin homeostasis-related gene expression fluctuation. The expressions of inflammatory chemokines and the genes responsible for the skin barrier function, such as filaggrin, fluctuated when inflammatory cytokines were applied to HaCaT cells. Then, we examined the effect of patchouli on the expression of several genes in HaCaT cells. As a result, patchouli was found to suppress the inflammatory chemokine expression induction to some extent and modulate MLN64 and MMP2 expressions. From the above, it was strongly suggested that some essential oils may have effects to suppress skin inflammation.