Department of Pharmaceutical Science, Musashino University, Nishitokyo, Tokyo 202-8585, Japan.
Biol Pharm Bull. 2010;33(8):1434-7. doi: 10.1248/bpb.33.1434.
Transient receptor potential vanilloid subtype 1 (TRPV1) is a non-selective cation channel activated by capsaicin. TRPV1 is expressed not only on human sensory neurons but also on human epidermal and hair follicle keratinocytes. Therefore, TRPV1 could have the potential to be a therapeutic target for skin disorders. To search for novel TRPV1 agonists, we screened 31 essential oils by using human TRPV1-expressing HEK293 cells. TRPV1 was activated by 4 essential oils: rose, thyme geraniol, palmarosa, and tolu balsam. The dose-response curves for TRPV1 activation by the essential oils revealed a rank order potency [the half-maximal effective concentration (EC(50))] of rose>palmarosa>thyme geraniol>tolu balsam, and rank order efficiency (% activity in response to 1 microM capsaicin) of tolu balsam>rose>palmarosa>thyme geraniol. Moreover, the dose-response curves for TRPV1 activation by citronellol (main constituent of rose oil) and geraniol (main constituent of thyme geraniol and palmarosa oils) were consistent with the potency and efficiency of each essential oil. In contrast, benzyl cinnamate and benzyl benzoate (main constituent of tolu balsam oil) and geranyl acetate (main constituent of thyme geraniol oil) did not show TRPV1 activity. In this first-of-its-kind study, we successfully investigated the role of some essential oils in promoting human TRPV1 activation, and also identified two monoterpenes, citronellol and geraniol, as new human TRPV1 agonists.
瞬时受体电位香草酸亚型 1（TRPV1）是一种非选择性阳离子通道，可被辣椒素激活。TRPV1 不仅在人类感觉神经元上表达，也在人类表皮和毛囊角质形成细胞上表达。因此，TRPV1 有可能成为皮肤疾病的治疗靶点。为了寻找新型 TRPV1 激动剂，我们使用人 TRPV1 表达的 HEK293 细胞筛选了 31 种精油。有 4 种精油可激活 TRPV1：玫瑰、香桃木香叶醇、香茅和丁子香酚香脂。精油激活 TRPV1 的剂量反应曲线显示出一种效力等级[半最大有效浓度（EC50）]，即玫瑰>香茅>香桃木香叶醇>丁子香酚香脂，以及一种效率等级（对 1 μM 辣椒素的反应百分比），即丁子香酚香脂>玫瑰>香茅>香桃木香叶醇。此外，香茅醇（玫瑰油的主要成分）和香叶醇（香桃木香叶醇和香茅油的主要成分）对 TRPV1 激活的剂量反应曲线与每种精油的效力和效率一致。相比之下，肉桂醇和苯甲酸苄酯（丁子香酚香脂油的主要成分）以及乙酸香叶酯（香桃木香叶醇油的主要成分）则没有 TRPV1 活性。在这项首例研究中，我们成功地研究了一些精油在促进人 TRPV1 激活方面的作用，还鉴定了两种单萜类化合物，香茅醇和香叶醇，作为新的人类 TRPV1 激动剂。
