Relaxation effects of Shikuwasa (Citrus depressa Hayata) essential oil inhalation: A randomized controlled trial in young adult females

IF 1.4 Q4 MEDICINE, RESEARCH & EXPERIMENTAL

Contemporary Clinical Trials Communications Pub Date : 2026-04-01 Epub Date: 2026-02-10 DOI:10.1016/j.conctc.2026.101613

Fumitake Yamaguchi , Miho Kuroki , Naoki Yoshinaga , Michikazu Nakai , Yasuji Arimura

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引用次数: 0

Abstract

Background

Shikuwasa (Citrus depressa Hayata) essential oil, rich in limonene and γ-terpinene, produces calming effects, but its psychological and physiological relaxation effects in humans remain unclear. This study examined the short-term relaxation effects of inhaling Shikuwasa essential oil compared to odor-free air among young adult females.

Methods

In this two-arm, parallel-group, open-label, randomized controlled superiority trial, healthy females aged 18–39 were randomly assigned to either the Shikuwasa essential oil group (n = 20) or the odor-free air group (n = 20). The primary outcome was subjective tense-arousal, measured using the Japanese version of the University of Wales Institute of Science and Technology Mood Adjective Checklist (JUMACL). Secondary outcomes included miosis rate, peripheral skin temperature, and cerebral blood flow. Due to measurement constraints, the experiment was divided into three 2-min inhalation phases.

Results

No significant between-group differences were observed in tense-arousal, miosis rate, or cerebral blood flow. Additional analyses of covariance, performed for each outcome variable using the Visual Analog Scale score and its interaction with the group as covariates, revealed a trend toward an interaction effect for the JUMACL tense-arousal subscale score, although the overall effects were not statistically significant.

Conclusions

Short-term inhalation of Shikuwasa essential oil did not significantly reduce tense-arousal or affect physiological indices in healthy, normal-to-low stress young adult females. However, aroma preference may influence psychological and neural responses. Future studies should consider pre-assessed aroma preference, longer inhalation durations, single-phase protocols, extended rest periods, and participants’ baseline mood.

Trial registration

This study was prospectively registered with the UMIN-CTR, UMIN000053914.

查看原文本刊更多论文

Shikuwasa （Citrus depressa Hayata）精油吸入的放松效果：一项针对年轻成年女性的随机对照试验

背景：shikuwasa （Citrus depressa Hayata）精油富含柠檬烯和γ-萜烯，具有镇静作用，但其对人体的心理和生理放松作用尚不清楚。本研究在年轻成年女性中检测了吸入石花精油与无气味空气的短期放松效果。方法将18-39岁的健康女性随机分为Shikuwasa精油组（n = 20）和无气味空气组（n = 20），采用双臂、平行组、开放标签、随机对照优势试验。主要结果是主观的紧张唤起，使用日语版的威尔士大学科技学院情绪形容词检查表（JUMACL）进行测量。次要结局包括细胞缩小率、外周皮肤温度和脑血流量。由于测量的限制，实验分为三个2分钟的吸入阶段。结果两组间在紧张觉醒、收缩率、脑血流量方面均无显著差异。使用视觉模拟量表得分及其与组的相互作用作为协变量，对每个结果变量进行了协方差分析，揭示了JUMACL紧张-觉醒子量表得分的相互作用趋势，尽管总体影响没有统计学意义。结论短期吸入石花精油对健康、正常至低应激的年轻成年女性的紧张唤醒及生理指标无显著影响。然而，香气偏好可能会影响心理和神经反应。未来的研究应考虑预先评估的香气偏好、更长的吸入持续时间、单相方案、延长的休息时间和参与者的基线情绪。本研究在UMIN-CTR中前瞻性注册，编号为UMIN000053914。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Contemporary Clinical Trials Communications Pharmacology, Toxicology and Pharmaceutics-Pharmacology

CiteScore

2.70

自引率

6.70%

发文量

146

审稿时长

20 weeks

期刊介绍： Contemporary Clinical Trials Communications is an international peer reviewed open access journal that publishes articles pertaining to all aspects of clinical trials, including, but not limited to, design, conduct, analysis, regulation and ethics. Manuscripts submitted should appeal to a readership drawn from a wide range of disciplines including medicine, life science, pharmaceutical science, biostatistics, epidemiology, computer science, management science, behavioral science, and bioethics. Contemporary Clinical Trials Communications is unique in that it is outside the confines of disease specifications, and it strives to increase the transparency of medical research and reduce publication bias by publishing scientifically valid original research findings irrespective of their perceived importance, significance or impact. Both randomized and non-randomized trials are within the scope of the Journal. Some common topics include trial design rationale and methods, operational methodologies and challenges, and positive and negative trial results. In addition to original research, the Journal also welcomes other types of communications including, but are not limited to, methodology reviews, perspectives and discussions. Through timely dissemination of advances in clinical trials, the goal of Contemporary Clinical Trials Communications is to serve as a platform to enhance the communication and collaboration within the global clinical trials community that ultimately advances this field of research for the benefit of patients.