• Journal of Environmental Science International
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• v.33 no.5
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• pp.333-343
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• 2024

This study aimed to investigate whether inhaling the aroma of essential oils could alleviate physiological stress responses and mimic the effects of forest therapy in urban settings. Briefly, 31 participants underwent stress index assessments for two days and inhaled the selected plant essential oils. The effects of this treatment on physiological responses were determined through electroencephalogram (EEG) and heart rate variability (HRV) measurements taken before and after inhaling the aroma of essential oils, extracting results for low frequency (LF) and high frequency (HF) components of HRV, as well as 𝜃 and 𝛼 brainwave activities. The results indicated that lavender oil did not yield significant differences, whereas pine, chamomile, and cypress oils exhibited significant differences in effects. Overall, stress relief was associated with enhanced 𝜃 and 𝛼 brainwave activities, a decrease in the LF component and an increase in the HF component of HRV. Among the essential oils studied, pine oil was the most effective. These findings underscore the potential of plant essential oils in replicating the therapeutic benefits of forest therapy, even in urban environments. Further investigations into their utilization are warranted to better understand and harness their therapeutic potential.

• Journal of Life Science
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• v.20 no.8
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• pp.1230-1234
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• 2010

The effects of inhaling three essential oils (lavender [Lavendular angustifolia], silver fir [Abies alba], and grapefruit [Citrus paradise]) against restraint stress were investigated in mice. Serum cortisol levels were significantly increased in the 1h-restraint group. Also, silver fir and grapefruit oils prevented the elevation of cortisol levels under experimental conditions. Inhalation of 10% lavender oil for 30 min before inducing stress significantly inhibited restraint-induced hypothermia. We also investigated the effects of restraint stress on triglycerides, total cholesterol, and high-density lipoprotein cholesterol. It was found that the concentration of triglycerides in the serum samples increased after restraint stress. Silver fir essential oil inhibited elevation of triglyceride levels. Taken all together, the correlation of herb essential oil inhalation against restraint stress in animals can partly be explained.

• Archives of Pharmacal Research
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• v.28 no.7
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• pp.770-774
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• 2005

This study investigated the stimulative or sedative effects of inhaling fragrant essential oils (EOs) by using a forced swimming test (FST) with mice. This behavioral test is commonly used to measure the effects of antidepressant drugs. The inhalation by mice of EOs, such as ginger oil (p<0.05), thyme oil (p<0.05), peppermint oil (p<0.05), and cypress oil (p<0.01) resulted in 5% to 22% reduction of immobility. The same results were achieved when over-agitation was artificially induced in the mice by an intraperitoneal injection of caffeine (a psycho-stimulant). In contrast, inhalation of some EOs by the mice resulted in increased immobility. To evaluate more correctly the sedative effects of EOs, the immobility of over-agitated mice induced with caffeine was ascertained after the inhalation of various EOs. Inhalation of lavender oil (p<0.01) and hyssop oil (p<0.01) increased the immobile state in mice that were treated with caffeine. The results of this study indicate that the inhalation of essential oils may induce stimulative or sedative effects in mice.

• Journal of Forest and Environmental Science
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• v.30 no.1
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• pp.62-70
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• 2014

The principle purpose of this research is to figure out whether the inhalation of Wood Essential oil (Chamaecyparis obtusa) affect not only human beings' concentration for surroundings but also change as to status of feelings. total number of subjects for this experimental are determined to be 66 (men 44 and women 22) among 85 adults who agreed to participate in this experiment after excluding 19 participants who were not able to smell scent due to flu and nasal inflammation. After both experimental group and control group being measured referring to their status of mood such as concentration, depression, vigor, fatigue, confusion, tension and anger, the experimental group is offered to get a piece of cotton that includes Wood Essential oil and they are asked to inhale it for 5 min. On the other hand, control group is offered to wait for the experimental group finishing inhaling wood Essential oil for 5 min. After 5 min, the status of mood from both groups were measured again. simultaneously, I conducted a survey targeting experimental group to see what their preferences are like regarding scent of wood essential oil. The experiment shows that the status of experimental group's concentration is improved about 0.94 point when compared to control group's. Moreover, Total mood disturbance is lower than control group's. Therefore it is proved that the inhalation of wood Essential oil alleviates overall status of mood. according to the analyses result of favor to scent for wood essential oil from experimental group, some of them who were positive got much better improvement when it comes to concentration and far more relieved on their feelings than those who weren't. Based from this result, it is definitely confirmed that there is a Phytoncide's psychophysiological effect which transcends the Placebo Effect generated by Phytoncide's positive image.