Citral in lemon myrtle, lemongrass, litsea, and melissa essential oils suppress the growth and invasion of breast cancer cells.

OBJECTIVE: Although cancer therapy suppresses recurrence and prolongs life, it may be accompanied by strong side effects; thus, there is a strong demand for the development effective treatments with fewer side effects. Cancer therapy using plant-derived essential oils is attracting attention as one promising method. This study investigated the antitumor effects of essential oil volatiles on breast cancer cells and identifies four essential oils that display antitumor activity. METHODS: Breast cancer cells were cultured in a 96-well plate, then one of twenty essential oils was added dropwise to the central well. The plate was incubated at 37 °C for 48 h and the effect of the volatile components of each essential oil on the surrounding breast cancer cell growth ability was examined using an MTT assay. Gas chromatography was used to investigate the concentration of the transpiration components that may affect cancer cells. RESULTS: Of the 20 essential oils, Lemongrass, Lemon myrtle, Litsea, and Melissa displayed strong anti-tumor effects. These essential oils inhibited the growth of nearby breast cancer cells, even when diluted more than 500-fold. The transpiration component of lemon Myrtle showed the strongest antitumor effect, but was the least cytotoxic to mononuclear cells in normal peripheral blood (PBMC). Each of these essential oils contained a very large amount of citral. The IC50 against breast cancer cells when citral was volatilized from each essential oil was 1.67 µL/mL for geranial and 1.31 µL/mL for neral. Volatilized citral alone showed strong anti-proliferation and infiltration-inhibiting effects. CONCLUSION: The transpiration components of Lemongrass, Lemon myrtle, Litsea, and Melissa are thought to inhibit breast cancer cell proliferation due to their high levels of citral.

Smell and Stress Response in the Brain: Review of the Connection between Chemistry and Neuropharmacology.

The stress response in the brain is not fully understood, although stress is one of the risk factors for developing mental disorders. On the other hand, the stimulation of the olfactory system can influence stress levels, and a certain smell has been empirically known to have a stress-suppressing effect, indeed. In this review, we first outline what stress is and previous studies on stress-responsive biomarkers (stress markers) in the brain. Subsequently, we confirm the olfactory system and review previous studies on the relationship between smell and stress response by species, such as humans, rats, and mice. Numerous studies demonstrated the stress-suppressing effects of aroma. There are also investigations showing the effects of odor that induce stress in experimental animals. In addition, we introduce recent studies on the effects of aroma of coffee beans and essential oils, such as lavender, cypress, α-pinene, and thyme linalool on the behavior and the expression of stress marker candidates in the brain. The transfer of volatile components into the brain is also discussed while using the results of thyme linalool as an example. These studies may provide a good opportunity to connect chemical research at the molecular level with neuropharmacological approaches in the future.

The Effect of Camellia Seed Oil Intake on Lipid Metabolism in Mice.

Camellia seed oil has mainly been applied to the production of cosmetics, and research into its dietary effects is required. Alterations in lipid metabolism by the intake of camellia seed oil were investigated. Health parameters such as diet intake, weight gain, fat mass, and plasma cholesterol and triglyceride levels were measured in mice fed a high fat diet containing camellia seed oil; comparisons were made to a normal diet and a high fat diet containing either soybean oil or olive oil as controls. No significant differences in weight gain and diet intake were observed between the groups. However, the camellia seed oil diet suppressed epididymal fat weight similarly to the olive oil diet. In total cholesterol and HDL (high density lipoprotein) cholesterol levels, the soybean oil, olive oil and camellia seed oil diet groups showed significant increases compared with the normal diet. However, increases in LDL (low density lipoprotein) cholesterol levels were inhibited by the camellia seed oil diet similarly to the olive oil diet. As the high oleic acid content of camellia seed oil is similar to that of olive oil, it is proposed that its presence mitigated fat accumulation and plasma cholesterol levels.

Intracerebral Distribution of a-Pinene and the Anxiolytic-like Effect in Mice Following Inhaled Administration of Essential Oil from Chamaecyparis obtuse.

The anxiolytic-like and stress reduction effects following inhaled administration of essential oil from Chamaecyparis obtusa (EOCO) have been reported. Volatile components are thought to produce these effects of EOCO by neurological transfer and pharmacological transfer. The regions of the brain in which inhaled compounds are found due to pharmacological transfer of EOCO are not known. This research was undertaken to clarify the relationship between the intracerebral distribution of α-pinene, which is the main component of EOCO, and emotional behavior. α-Pinene was detected as the main component of volatile EOCO. The amount of α-pinene in each region of the brain was measured following inhaled administration of EOCO. The amount of α-pinene was different in each region of the brain. With inhaled administration of 32 µL/L air EOCO, a high concentration of α-pinene was observed. However, no significant differences in the concentration of α-pinene among brain regions were found. A therapeutic concentration of α-pinene (8 µL/L air EOCO) in each region of the brain may induce an anxiolytic-like effect, and a high concentration of α-pinene (32 µL/L air EOCO) in each region of the brain may induce an excitatory-like effect. The increases in the concentration of α-pinene from 8 to 32 µL/L air EOCO in the striatum and the hippocampus were significantly lower compared with the increases in other brain regions. These results indicate that regions besides the striatum and the hippocampus participated in the increase in locomotor activity due to the high concentration of α-pinene in the brain.

Relationship Between Emotional Behavior in Mice and the Concentration of (+)-α-Santalol in the Brain.

We previously reported finding anxiolytic-like activity for sandalwood oil after administration in mice. In this report, we further investigated the emotional behavior associated with inhaled or intraperitoneally administered (+)-α-santalol, the main component of sandalwood oil, in addition to examining whether pharmacological or neurological transfers are responsible for this behavior. After administration of (+)-α-santalol by inhalation or intraperitoneal injection, we assessed anxiolytic-like and locomotor activities using elevated-plus maze tests. We also examined the relationship between the emotional behavior and the (+)-α-santalol brain concentration. Anxiolytic-like activity was not observed immediately after administration or after water-immersion stress for 24 h for either the (+)-α-santalol 2 µL/L air inhalation or the (+)-α-santalol 0.03 mL/kg (i.p.) administration. However, mice administered (+)-α-santalol 0.03 mL/kg intraperitoneally exhibited a significant decrease in the locomotor activity after exposure to water-immersion stress for 24 h. The brain (+)-α-santalol concentration was 2.6 µg/g tissue after (+)-α-santalol 0.03 mL/kg (i.p.) administration. The observed shift of (+)-α-santalol to the brain suggests that this component acts via pharmacological transfer and is responsible for the sedative effect but not the anxiolytic-like activity.

Expression of BDNF and TH mRNA in the brain following inhaled administration of α-pinene.

Essential oils are mainly administered by inhalation. Administration by inhalation is considered to occur through two pathways, neurological transfer and pharmacological transfer. However, the relationship between the two routes is not clear. To clarify this relationship, we administered α-pinene, which has an anxiolytic-like effect, to mice. Emotional behavior and accumulation and expression of relevant mRNAs in the brain (brain-derived neurotrophic factor (BDNF); tyrosine hydroxylase (TH)) were examined following inhaled administration of α-pinene (10 µL/L air for 60 or 90min). To evaluate the anxiolytic-like effect, the elevated plus maze (EPM) test was used. Inhalation of α-pinene for 60 min produced a significant increase in the total distance traveled in the EPM test compared with control (water). The concentration of α-pinene in the brain after 60 min of inhalation was significantly increased compared with that after 90 min of inhalation. The expression of BDNF mRNA in the olfactory bulb and in the hippocampus was almost the same after 60 min of inhalation compared to that after 90 min of inhalation. The expression of TH mRNA in the midbrain after 60 min of inhalation was significantly increased compared with that of the control. Thus, an increase in α-pinene in the brain induces an increase in TH mRNA expression and increases locomotor activity. The anxiolytic-like effect may be related to both neurological transfer and pharmacological transfer.

Daily inhalation of α-pinene in mice: effects on behavior and organ accumulation.

In phytotherapy, essential oils tend to be used daily for a period of days or weeks, rather than in a single application. However, the literature contains very little information on repeated use of essential oils. In this study, we investigated the effects on behavior and the accumulation in the brain and liver of α-pinene, an essential oil component, when inhaled by mice. Animals were individually housed in cages for 1 week. Mice inhaled α-pinene or water vapor (negative control) for 90 min/day for 1 day, 3 days, or 5 days, and they were then submitted to the elevated plus maze test for 10 min. We used gas chromatography with flame ionization detection to quantify concentrations of α-pinene in the brain and liver. There was significant anxiolytic-like activity, which remained constant for the 5 days' inhalation of α-pinene. On the other hand, the accumulation of α-pinene in the brain and liver peaked on the third day of inhalation. The existence of stress related to the new environment appears to have affected the change in the accumulation of α-pinene in the internal organs, keeping the anxiolytic-like action constant.

Anxiolytic-like effect of inhalation of essential oil from Lavandula officinalis: investigation of changes in 5-HT turnover and involvement of olfactory stimulation.

Essential oil extracted from Lavandula officinalis (LvEO) has a long history of usage in anxiety alleviation with good evidence to support its use. However, findings and information regarding the exact pathway involved and mechanism of action remain inconclusive. Therefore, we aimed to (1) reveal the influence of olfactory stimulation, and (2) determine whether the serotonergic system is involved in the anxiolytic effect of LvEO when it is inhaled. To this end, we first compared the anxiety-related behaviors of normosmic and anosmic mice. LvEO inhalation caused notable elevation in anxiety-related parameters with or without olfactory perception, indicating that olfactory stimulation is not necessarily required for LvEO to be effective. Neurochemical analysis of the serotonin (5-HT) turnover rate, accompanied by EPM testing, was then performed. LvEO significantly increased the striatal and hippocampal levels of 5-HT and decreased turnover rates in accordance with the anxiolytic behavioral changes. These results, together with previous findings, support the hypothesis that serotonergic neurotransmission plays a certain role in the anxiolytic properties of LvEO.

Anxiolytic-like effect of Illicium verum fruit oil, trans-anethole and related compounds in mice.

The fruit of Illicium verum Hook. f. (star anise) is used by many as a spice. The fragrance of I. verum fruit is characteristically anise-like. In this study, hexane-extracted I. verum fruit oil (IVO), trans-anethole as the main component, and related compounds (propiophenone, 4'-methoxy-propiophenone, trans-ß-methylstyrene) were analyzed in order to clarify the emotional effect of inhaling the fragrance of I. verum fruit. As a result, although 4 µL/L air IVO did not exhibit an anxiolytic-like effect, 1 µL/L air trans-anethole exhibited a significant effect (p < 0.05). Moreover, the anxiolytic-like effect of 1 µL/L air trans-anethole was significantly greater than 1 µL/L air propiophenone and 1 µL/L air 4'-methoxy-propiophenone (p < 0.05). Thus, the anxiolytic-like effect of trans-anethole was confirmed, and it is proposed that the methoxyl group and 1-propenyl group in the para position of the benzene ring are necessary for the effect.

Effect on emotional behavior and stress by inhalation of the essential oil from Chamaecyparis obtusa.

Various effects have been reported in the literature for the essential oil from Chamaecyparis obtusa (EOCO), such as antibacterial and antifungal activity. In this study, we examined the effect of EOCO on emotional behavior and stress-induced biomarkers. Male ICR mice, aged 5 weeks at the start of each experiment, were individually housed in cages for 1 week. After placing each mouse in a glass container and exposing it to EOCO for 90 min, we then investigated the influence on emotional behavior using the elevated-plus maze (EPM) test, which is one of the evaluation methods for anxiolytic-like behavior. Significant anxiolytic-like effects were observed for the 7.0 mg/L air EOCO (P < 0.05). After the EPM test, mice were dissected and changes in the stress-induced biomarkers within the brain were investigated by examining the amounts of fast nerve growth factor receptor (NGFR) and activity regulated cytoskeletal-associated protein (Arc) gene expression, and brain-derived neurotrophic factor (BDNF) and galactokinase 1 (GLK1) protein expression. Significant increases were observed in the amount of NGFR after inhalation of 7.0 mg/L air EOCO (P < 0.05). These results indicate that EOCO has both anxiolytic-like and stress mitigation effects.

Anxiolytic-like effect of Shigyakusan extract with low side effects in mice.

Shigyakusan is a traditional Japanese herbal (Kampo) medicine used to treat inflammatory conditions such as cholecystitis and gastritis as well as psychiatric disorders. This study examined the anxiolytic-like effect of Shigyakusan extract (SS), and evaluated the activity of the main compound. Three behavioral tests in mice were used to evaluate the activity of SS. Samples were administered orally over a 10-day period. A light and dark box (LDB) test was performed on the 8th day, while an open field (OF) test was done on the 9th day, and an elevated plus maze (EPM) test was performed on the 10th day. Diazepam (DZ), a typical anxiolytic drug, was used as the positive control. Administration of 10 mg/kg DZ resulted in a significant anxiolytic-like effect in the LDB and EPM tests, while administration of 0.3 g/kg SS resulted in a weak anxiolytic-like effect. In the OF test, while DZ caused a significant reduction of locomotor activity, SS did not cause any changes compared to the water controls. This suggests that locomotor activity may be a side effect of DZ, and thus SS, which lacks this response, may be a more useful treatment. Quantitative analysis performed to clarify the activity of the main compound also determined that SS contained 51.4 mg/g naringin, which also has been reported to have anxiolytic-like activity. Since these results suggested that this compound might be responsible for the activity of SS, we subsequently examined the oral administration of a similar dose of naringin. Although we observed a tendency for a weak anxiolytic-like effect, this effect was not greater than that seen for SS.

Organ accumulation in mice after inhalation of single or mixed essential oil compounds.

Essential oils are composed of multiple components. It is thought that the effect of essential oils is due to specific component ratios, which may differ from the original ratio when the essential oil is absorbed. However, very little detailed research exists in this area. We studied the distribution of essential oil components after inhalation of single and mixed components in mice. This research was done using four main components of Alpinia zerumbet (Pers.) B. L. Burtt. and R. M. Sm.: α-pinene, p-cymene, 1,8-cineole, and limonene. After inhalation of single or mixed components for 90 min, component levels in the brain and liver of mice were measured. The results indicated that the amount of α-pinene in the brain and liver was twofold greater after mixed-component inhalation than that after single-component inhalation. In a comparison of the components of the mixed inhalation, the ratio of α-pinene increased to about three times that of 1,8-cineole. It is thought that the absorption via the nasal mucus greatly influences this phenomenon. The results of this investigation of the bodily distribution of essential oil volatile components may provide clues for elucidating their action.

Effect of aromatherapy massage on elderly patients under long-term hospitalization in Japan.

OBJECTIVES: To verify the effectiveness of aromatherapy massage on elderly patients under long-term hospitalization. DESIGN: Aromatherapy massage was performed twice a week for a total of eight times. SETTING: Nursing home. SUBJECTS: Elderly women under long-term hospitalization. INTERVENTIONS: Questionnaire and measurement of stress marker levels (salivary amylase activity) before and after the first, fifth, and eighth aromatherapy massages. OUTCOME MEASURES: Questionnaire (Face scale, General Health Questionnaire-12 [GHQ-12]), measurement of salivary amylase activity. RESULTS: A decrease in stress after aromatherapy massage compared to before each massage was confirmed at all measurement times and with the stress marker. No marked reduction was observed in Face scale or saliva amylase activity as a whole over the long term, although decreasing tendencies were seen. Marked reductions in GHQ-12 were observed over the long term. CONCLUSIONS: Aroma massage appears likely to prove effective in reducing psychological stress among elderly patients under long-term hospitalization.

Effects of inhaled lavender essential oil on stress-loaded animals: changes in anxiety-related behavior and expression levels of selected mRNAs and proteins.

Inhalation of various essential oils elicits behavioral changes as a consequence of a complex centrally coordinated response. To understand the molecular mechanisms of action of aromatic compounds on emotional responses, we evaluated the stress-induced changes in mouse brain and the efficacy of inhaled essential oil from Lavandula officinalis (LvEO) using two approaches: a behavioral test, and examining the expression levels of selected genes {fast nerve growth factor receptor (NGFR) mRNA, activity regulated cytoskeletal-associated protein (Arc) mRNA} and proteins {galactokinase 1 (GLK1) and brain-derived neurotrophic factor (BDNF)}. Animals were randomly divided into 4 groups depending on the treatment given: stress (-)/H20, stress (-)/LvEO, stress (+)/H2O, and stress (+)/LvEO group. For behavioral testing, using an elevated plus-maze test, significant anxiolytic-like effects were seen in both the stress (-)/LVEO and stress (+)/LvEO groups, indicating that LvEO exerts anxiolytic-like effects regardless of the administration of water immersion stress. On expression analysis, the levels of NGFR and Arc mRNA were significantly lower in animals subjected to stress. Inhalation of LvEO, however, reversed this change, thus suggesting that LvEO negates the impact of stress on gene expression levels. Meanwhile, significant decreases in expression levels were also observed in the stress (-)/LvEO group, which implies that LvEO, when given in a stress-free situation, may act as a stress stimulus. Taken together, our data suggest that inhalation of LvEO exerts bidirectional influences in the central nervous system (CNS) of animals, either attenuating the effects of stress or acting as a stressor, depending on the subject state.

Components of essential oils extracted from leaves and shoots of abies species in Japan.

The essential oils extracted from the leaves and the shoots of five Abies species (Pinaceae) growing in Japan, i.e., A. firma, A. homolepis, A. veitchii, A. mariesii, and A. sachalinensis, were characterized by GC-FID and GC/MS analyses. The yields of the essential oils extracted from A. sachalinensis were the highest among them. A significant amount of α-pinene was contained in the essential oils of all the Abies species examined. In A. homolepis and A. veitchii, significant differences in the content of the essential oils were found depending on whether these were extracted from the leaves or from the shoots. Regarding the enantiomeric ratio of α-pinene, the (+)-enantiomer was predominant in the oil extracted from the leaves of A. firma, while (-)-α-pinene was present in higher amounts in the oils of A. veitchii (leaves and shoots), A. mariesii (leaves and shoots), and A. sachalinensis (shoots). The fact that there may be a quantitative and qualitative difference in the components of the essential oils extracted from the different parts of a plant was investigated by cluster analysis.

Interspecies comparison of chemical composition and anxiolytic-like effects of lavender oils upon inhalation.

Essential oils have traditionally been used for decades to alleviate the symptoms of various mental problems. In terms of anxiolytic-like properties, lavender oil is probably the most commonly used and best-studied essential oil. Although there is compositional variance among the oils extracted from different origins, there have been few studies performed to date to investigate how these differences affect the expression of anxiolytic-like activity. This paper discusses the interspecies differences and contributions of the main constituents in the expression of anxiolytic-like effects upon inhalation, as assessed in mice by the elevated-plus maze test, by comparing the essential oils from six different species of Lavandula. The results showed qualitative and quantitative variations in the tested oils, which results in significant differences in their anxiolytic-like activities. Our findings also suggest that linalyl acetate (LA) works synergistically with linalool (LO) and that the presence of both LA and LO is essential for the whole oil to work as an inhaled anti-anxiety agent.

Anxiolytic effect and tissue distribution of inhaled Alpinia zerumbet essential oil in mice.

The use of essential oils is common throughout the world, and clarification of their detailed effects and pharmaceutical potencies is necessary. Additionally, detailed information regarding the pharmacokinetics of essential oils is needed. In this report, GC-MS analysis was used to observe the tissue distribution of the multiple components of Alpinia zerumbet (Pers.) B.L. Burtt. et Sm. Anxiety-related behavior was evaluated by the light and dark box test (LD), open field test (OF), and elevated plus maze test (EPM). GC-MS quantification of the major components of A. zerumbet essential oil (AZEO) (alpha-pinene, p-cymene, 1,8-cineole, and limonene) was almost identical using either the injection or headspace injection method. All the behavioral assessments indicated that inhalation of AZEO had a positive anxiolytic effect. This was especially evident in the EPM (time spent in the open arms), where anxiolytic effects were clearly observed (P < 0.05). Alpha-Pinene accumulated in the brain at almost the same rate as in the liver. However, the oil components chiefly accumulated in the kidney. Therefore, the essential oil component in the largest proportion will not necessarily be distributed to organs throughout the body in the same quantities and/or ratios. It is necessary to consider tissue distribution for investigating the effects of essential oil inhalation.

Composition and seasonal variation of the essential oil from Abies sachalinensis from Hokkaido, Japan.

The composition of the steam-distilled essential oil from the leaves of Abies sachalinensis (F. Schmidt) Mast. cultivated in Hokkaido (Japan) was studied by GC-MS. The seasonal variation in the main volatile constituents was also investigated. Analysis of the essential oil resulted in the identification of 21 compounds with monoterpenes comprising 99.9% of the total. alpha-Pinene was the most abundant compound, followed by camphene, bornyl acetate, limonene, beta-pinene and beta-phellandrene. The sesquiterpene content was low, and was mainly represented by beta-caryophyllene, beta-caryophyllene, and gamma-selinene. The essential oil from the leaves, collected at eight different collection periods over more than 5 years, showed significant differences in composition. Alpha-Pinene was the predominant constituent during the collection periods, with a few exceptions. The alpha-pinene content of the oil was abundant in April-June, and decreased in November-December. Levels of bornyl acetate showed the greatest increase in December, when the temperature was very low. The enantiomeric distribution of alpha-pinene was suggested to relate to seasonal transformation. (+)-alpha-Pinene showed a tendency to increase when total precipitation, average temperature, and total duration of sunshine were high.

Triterpenoid saponins from Impatiens siculifer.

Triterpenoid saponins, impatienosides A-G, together with 12 known saponins, were isolated from the whole plants of Impatiens siculifer. Their structures were established on the basis of extensive 1D and 2D NMR and MS analyses coupled with chemical degradation. Cytotoxic activities of the isolated saponins were evaluated against three human cancer cell lines: human myeloid leukemia HL-60 cells, human stomach KATO-III adenocarcinoma, and human lung A549 adenocarcinoma.

Effects of the essential oil from leaves of Alpinia zerumbet on behavioral alterations in mice.

In phytotherapy, the essential oil from the leaves of Alpinia zerumbet (Alpinia speciosa K. Schum.) (EOAZ) is used for neuropsychiatric symptoms, such as depression, stress and anxiety, and chronic problems that are associated with reproductive hormone imbalances in women. The chemical composition of EOAZ was analyzed by GC/MS, and the EOAZ properties inducing behavioral alterations in mice were examined by behavioral observations (BO) and an elevated plus-maze task (EPM), widely used as a method for assessing anxiolytic-like behaviors. Five major compounds, p-cymene (28.0 +/- 5.0%), 1,8-cineole (17.9 +/- 4.2%), terpinen-4-ol (11.9 +/- 6.3%), limonene (6.3 +/- 2.2%), and camphor (5.2 +/- 2.1%) were identified by retention indices, mass spectra and comparison with standards. Inhalational administration of EOAZ (8.7 ppm) induced unique jumping behaviors in mice. To further investigate the behavioral regulatory mechanisms of EOAZ, we administered an intraperitoneal injection of either 10 mg/kg 5-HTP or 10 mg/kg fluoxetine prior to the EOAZ inhalations. By 5-HTP or fluoxetine pretreatments, the jumping frequencies were significantly decreased. In EPM, EOAZ (0.087 and 8.7 ppm) obviously showed the anxiolytic-like activity in mice.