INTRODUCTION
Lavender ( Lavandula L. ) is a flower belonging to the family of Lamiaceae which contains more than 40 different species of lavender and also many hybrid kinds.
It grows in the Mediterranean area where arid and pebbly grounds are not hard to find, especially the cultivation of lavender fields is traditionally to refer to Provence (a region of southern France adjoining Italy) where we can even find a museum dedicated to the flower: le musee de la lavande .
Lavender is renowned since the lateen Plinius the Elder and on trough the popular traditions not only for being a pleasant smelly plant but also for its medical properties.
MEDICAL PROPERTIES
The inhalation of lavender oil induce a change in mood making subjects more calm, pleasant and comfortable; this is not only an effect induced in the subjects by the conviction of the efficacy of the oil, but it has been noticed a decrease in autonomic arousal.
To prove those effects of lavender oil on the central nervous system, autonomic nervous system, and mood responses in humans after inhalation it has been carried out this experiment. (The effects of lavender oil inhalation on emotional states, autonomic nervous system, and brain electrical activity, 2012 )
Agroup of healthy volunteers in the number of twenty was monitored for autonomic parameters such as blood pressure, heart rate, respiratory rate, and skin temperature to determine the arousal level of the autonomic nervous system. Also, to complete the features of clinical analysis electroencephalogram ( EEG ) was recorded from 31 electrodes on the scalp according to the international 10 to 20 system, and EEG power spectra were calculated by Fast Fourier Transform (FFT).
Furthermore subjects were asked to estimate their mood responses such as feeling pleasant or unpleasant, uncomfortable, sensuality, relaxation, or refreshing in order to assess subjective behavioral arousal. Finally,
Data was analyzed by comparing the effects of lavender oil on physiological and mood states with sweet almond oil. These assessments were measured before and after using paired t-test statistical procedure.
The results revealed that lavender oil caused significant decreases of blood pressure , heart rate, and skin temperature , which indicated a decrease of autonomic arousal . In terms of mood responses, the subjects in the lavender oil group categorized themselves as more active, fresher and relaxed than subjects just inhaling base oil. Compared with base oil, lavender oil increased the power of theta (4-8 Hz) and alpha (8-13 Hz) brain activities. The topographic map showed obviously more scattering power in alpha range waves particularly in bilateral temporal and central area.
Also in essential hypertension lavender essential oil has effects on systolic blood pressure making it decrease after many administrations and contributing to lower sympathetic nerve system activity. (Effects of aromatherapy on changes in the autonomic nervous system, aortic pulse wave velocity and aortic augmentation index in patients with essential hypertension, 2010 )
The experimentation to demonstrate this ability has been conducted this way: with a coin toss selection, 22 participants were assigned to the experimental group and 20 to the control. The experimental group was given a blend of oils of lemon (Citrus limonum), lavender (Lavandula angustifolia), and ylang ylang (Cananga odorata) which were prepared in the ratio of 2:2:1, respectively. The control group was given an artificial lemon fragrance of Limonene (35 cc) and Citral (15 cc) mixture. The experiment, inhalation, was conducted for 3 weeks (2 min per inhalation, 2 times per day) to both groups.
| group | number | treatment |
|---|
| exmperiment | 22 | oils of lemon,lavender and ylang ylang |
| control | 20 | artificial fragrance of limonene and citral mixture |
There was a noticeable difference in systolic blood pressure between the groups (p=.001), however the difference in diastolic blood pressure between the two groups was not significant. There was a notable difference in sympathetic nerve system activity of heart rate variability (p=.047). However, the differences in aortic pulse wave velocity or the aortic augmentation index were not significant.
Inhalation of lavender essential oil induces behavioral changes as a consequence of a complex centrally coordinated response. To inqire into the action of the aromatic compounds of the oil on emotional responses at a molecular level, it has been evaluated the stress-induced changes in mouse brain and the efficacy of inhaled essential oil from Lavandula officinalis (LvEO).(Effects of lavender essential oil on stress-loaded animals:changes in anxiety-related behavior and expression levels of selected mRNAs and proteins,2012 )
Mice were evaluated trough 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,
- stress (+)/LvEO.
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.
Therefore for its properties lavender oil has been used in the preparation of a drug called Silexan (An orally administered lavandula oil preparation (Silexan) for anxiety disorder and related conditions: an evidence based review, 2013 ) employed in the treatment of anxiety disorder. Silexan had beneficial effects on typical co-morbidity symptoms of anxiety disorders, for example, disturbed sleep, somatic complaints, or decreased quality of life. Except for mild gastrointestinal symptoms, the drug was devoid of adverse effects and did not cause drug interactions or withdrawal symptoms at daily doses of 80 or 160 mg.
