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.

This study determined the vitamin E and phytosterol content in carrier oils for aromatherapy. We analyzed vitamin E homologue α-, β-, γ-, and δ-tocopherols and α-, β-, γ-, and δ-tocotorienols and three phytosterol kinds (campesterol, stigmasterol, and β-sitosterol) in those carrier oils, using gas chromatography-mass spectrometry (GCMS) in selected ion monitoring mode. Vitamin E and phytosterols, which have functional properties, such as antioxidation, skin cornification prevention, and anti-inflammation, were detected in varying proportions in many carrier oils studied here. Among the 22 carrier oils, organic calendula oil has the richest tocopherol and α-tocopherol followed by wheat germ and organic arnica oils. Tocotorienols were detected in 13 carrier oils. Grapeseed oil contained all the vitamin E homologues and has the highest α-tocotorienol content among all the samples. Phytosterol content was predominant in wheat germ and jojoba virgin oils and in most other oils. These results suggest that the role of carrier oils in skin treatment will also have some of the physiological effects of vitamin E and phytosterols on the skin, in addition to the physical effect of the oil.

[Introduction] The symbolic tree of Kagoshima Prefecture is a camphor tree. Historically, camphor was produced from camphor tree at the Satsuma Domain in Edo period. Even today, the rare natural essential oil in the world from Hosyo, a kind of camphor tree, is produced by Kaimon district at Ibusuki city in Kagoshima Prefecture. L-linalool, one of the main lavender essential oil ingredients having a sedative effect, is the main ingredient of the Hosyo essential oil. Various previous studies have shown that aromatherapy with lavender essential oil has a relaxing effect. The study aims to investigate the effect of the essential oil from Hosyo on the autonomic nervous system by pulse wave. [Methods] Seventeen healthy young females attended the study and were in the sitting position on a chair. In this study, every subject underwent a 5-minute rest, 5-minute aromatherapy, and 10-minute post aromatherapy in correct order. Simultaneously, pulse wave is gained from the fingertip pulse wave meter. The subjects smelled a drop (0.05 mL) of Hosyo essential oil on the tissue paper. Five fingertip pulse wave parameters (HF, LF/HF, pulse, CVRR, entropy) were calculated and analyzed using TAOS company product. HF is the indicator of parasympathetic nervous system activation; LF/HF is the sympathetic nervous system indicator. Before and after the study, fatigue using VAS, Japanese Society of Fatigue Science evaluation form, and the likes and dislikes of Hosyo essential oil are assessed. Questionnaires to fragrance were also distributed and answered. [Results] Aromatherapy has a meaningful increase in HF and decrease in LF/HF compared that of the rest. Pulse wave showed gradually decrease during aromatherapy. Fatigue with VAS was meaningfully improved. [Conclusion] Only the 5-minute aromatherapy with Hosyo essential oil activated and inhibited the parasympathetic and sympathetic nervous system, respectively. This aromatherapy shows immediate effect.