The prevalence of obesity has dramatically increased worldwide. Obesity is a significant independent predictor of cardiovascular risk, and cardiovascular disease is the leading cause of morbidity and death. It is well known that physical exercise plays an important role in metabolism. However, few people continuously exercise because weight management is not an easy task for many people. Therefore, successful strategies for reducing obesity together with improving metabolic risk factors are of utmost importance. Ten mildly obese middle-aged women (53.6±8.0 years, BMI 24.5±3.2) participated in a randomized, crossover study (aroma and control trials). Subjects were examined on two separate occasions. Each subject participated in an aerobic exercise training program using an aero-bike for 20 min. This experiment used grapefruit oil (Citrus paradisi) aroma stimulation. In this experiment, we measured heart rate and rating of perceived exertion (RPE) scale as a subjective index, before and during exercise. The aroma trial resulted in a significantly decreased RPE compared with that during the control trial during exercise. The present study indicated that inhalation of grapefruit oil could contribute to the improvement of RPE, an indicator of subjective index, during exercise. This study further implies that inhalation of grapefruit oil offers an effective therapeutic strategy for preventing obesity.

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A randomized crossover trial was performed to examine the effect of essential oils on numerical ability and mood in elementary school students. Participants were 38 healthy students attending sixth grade (11–12 years of age). The students were randomly assigned to two groups: one group was tested with peppermint oil and the other group was tested with sweet orange oil. A crossover experimental procedure was conducted using purified water as a control after a washout period to remove the effect of the previous procedures. Mood change was evaluated using a two-dimensional mood scale short term (TDMS-ST) and visual analog scale (VAS); numerical ability was assessed based on the number of single-digit additions attempted on a 100 squares calculation grid in 10 minutes, as well as the number of incorrect responses. Finally, the ability to access vocabulary was evaluated using verbal fluency tasks. Olfactory stimulation with essential oil inhalation for 30 seconds, followed by continuous exposure with the scented plate on the table was performed. VAS scores for concentration, feeling refreshed, and energy showed a significant increase with peppermint oil compared to purified water. A comparison of VAS scores for sweet orange oil with those for purified water showed significant increases for absence of irritation, motivation, absence of anxiety, vigor, and feeling refreshed. There were significant increases in the TDMS-ST for vitality level, stability level, and pleasure level with the sweet orange oil. There were no significant differences in the 100 squares calculation between peppermint oil, sweet orange oil, and purified water. However, the mean number of incorrect responses for peppermint oil was 3.2 compared to 4.2 for purified water (a 24% decrease); for sweet orange oil, the mean number of incorrect responses was 3.2 compared to 4.4 for purified water (a 27% decrease). However, there were no significant differences. Furthermore, there were no significant differences in the verbal fluency tasks between peppermint oil, sweet orange oil, and purified water. These results suggest that peppermint oil and sweet orange oil affect mood in elementary school students by leaving them refreshed, and may affect numerical ability.

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Adult T-cell leukemia (ATL) is a highly aggressive malignancy of CD4⁺ T cells caused by human T cell leukemia virus type I (HTLV-I). Transcription factor, NF-κB, is constitutively activated in primary ATL cells and plays a central role in leukemogenesis by contributing to the pathogenesis of ATL. Thus, specific NF-κB inhibitors block proliferation of ATL cells. Here we examined whether 30 essential oils exhibit NF-κB inhibitory effect as well as anti-ATL effects using a human HTLV-I-infected T-cell line, MT-2. Among 30 oils, Geranium, Ylang-ylang, Juniper, and Jasmine oils significantly inhibited cellular growth. Geranium oil especially induced an inhibition of constitutive NF-κB activation as well as the caspase-dependent apoptotic cell death of MT-2. These results suggest that Geranium oil has strong NF-κB inhibitory and anti-ATL effects. These findings demonstrate that Geranium oil and its components might be useful in molecular targeted therapies and palliative care for several cancer and inflammatory diseases, in which activation of NF-κB occurs.

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