Lavender
Lavenders (Lavandula spp.) belong to the family Labiatae (Lamiaceae) and have been used either dried or as an essential oil for centuries for a variety of therapeutic and cosmetic purposes. It has a long history as an herbal remedy in traditional medicine to improve mood and as a sleep aid. The word lavender comes from the Latin root “lavare” which literally means “to wash.” The earliest recorded use of lavender dates to ancient Egypt. There, lavender oil played a role in the mummification process. In later times, lavender became a bath additive in several regions,including ancient Persia, Greece, and Rome. These cultures believed that lavender helped purify the body and mind.
Today, lavender is primarily grown in northern Africa and the Mediterranean mountains, often for extraction of its essential oils. Lavender essential oil is produced, usually by steam distillation, from both the flower heads and foliage, but the chemical composition differs greatly, with the sweeter and most aromatic oil being derived from the flowers.
Uses
Lavender has a long history as an herbal remedy in traditional medicine to improve
mood and as a sleep aid. Several studies suggest that lavender may reduce anxiety,
depression, and pain (migraines) and improve sleep.
Chemistry/Pharmacology
The main constituents of lavender oil are linalool, linalyl acetate, 1,8-cineole, -ocimene
(usually both cisand trans-), terpinen-4-ol and camphor. Each of these constituents
can vary significantly in oils derived from different cultivars with the relative levels of
each being the main determinant of market value, application, and aroma.
Aroma analysis of those plants with typical scents has demonstrated that oils derived
from L. stoechas and L. lanata have high camphor levels while L. angustifolia, L.
dentata and L. pinnata are low (<2%) in camphor. These low camphor plants tend
also to have higher levels of terpenes (e.g. beta-phellandrene) and sesquiterpenes (e.g.
caryophyllene).
Clinical Studies
Preclinical data suggest anxiolytic, anticonvulsant, neuroprotective, cardioprotective,
antimicrobial, anti-inflammatory, and antioxidant effects. In dementia models,
lavender oil inhalation reversed spatial memory loss. Several studies suggest lavender
may be helpful for anxiety, and depression, and to improve sleep.
Studies in humans of both oral formulas and lavender aromatherapy have been
conducted. Clinical trials suggest benefits with oral lavender preparations against
depression and anxiety.
Studies of lavender aromatherapy suggest it may help reduce preoperative anxiety as
well as postoperative analgesics and various types of pain, but it did not lower anxiety
during radiotherapy. Other studies of inhaled lavender found improvements in sleep
quality, post-acute-stress memory and physiologic function, dysmenorrhea and
emotional symptoms, premenstrual syndrome, menopause flushing ( , migraine
frequency, agitation and falls in older individuals , and dementia symptoms.
Various meta-analyses suggest benefits with either oral lavender or aromatherapy for
anxiety and menopausal symptoms, but additional high-quality studies are needed to
confirm safety and efficacy.
Preclinical studies suggest the anticancer effects of lavender against various cancer cell
lines. Animal studies that employed the monocyclic terpene perillyl alcohol
(POH) derived from several herbs including lavender showed tumor inhibition and
regression, but studies in humans are needed.
Biomechanical Mechanism
Anti-inflammatory and analgesic effects of lavender are attributed to 1,8-cineole (2) .
Other major constituents include linalool and linalyl acetate, which may relax blood
vessels and induce anxiolytic effects. In a murine model, exposure to linalool odor
induced anxiolytic effects without motor impairment.
Lavender oil also has broad-spectrum antibacterial activity. It reversed bacterial
resistance to piperacillin in multi-drug-resistant E.coli via alterations of outer
membrane permeability and bacterial quorum sensing inhibition; and prevented
immediate-type allergic reactions by inhibiting mast cell degranulation. Antimicrobial
activity was synergistic or additive when combined with other essential oils, with the
most favorable combinations being cinnamon or sweet orange oil against C.
albicans and S. aureus, respectively.
In addition, lavender has CNS depressive effects. In animal models, it attenuated
neuronal damage and upregulated catalase, superoxide dismutase, glutathione
peroxidase, and the glutathione/glutathione disulfide ratio. Activity in stroke models
includes increased endogenous antioxidant defense, oxidative stress inhibition, and
increased VEGF expression. In an Alzheimer’s disease model, lavender extract
improved spatial performance by diminishing beta-amyloid production in the
hippocampus. In mice with anosmia, anxiolytic effects with lavender inhalation were
likely due to serotonergic mechanisms rather than olfactory activation. However,
whether lavender alleviates or exacerbates anxiety may be determined by genetic
influences on temperament as these behaviors were amplified after exposure to
lavender inhalation in calm versus nervous sheep. Antiepileptic effects are due to
suppressed nitric oxide levels in the brain. Cardioprotective effects are attributed to
lavender’s antioxidant properties. In wound healing models, lavender oil accelerated
re-epithelialization and wound closure via enhanced epidermal growth factor
secretion.
In young women with premenstrual syndrome, lavender inhalation increased the high-
frequency component of heart rate variability, reflecting parasympathetic nervous
system activity. Although lavender reduced anxiety during urodynamic assessments by
increasing gamma-aminobutyric acid inhibitory effects in the amygdala, blood
pressure increases were attributed to potential diuretic activity. A positron emission
tomography study revealed anxiolytic effects may occur via reduced serotonin-1A
receptor binding. Effects on preoperative anxiety were attributed to both the use of
lavender aroma as well as the placebo effect of added attention to patients.
An aqueous lavender extract inhibited lymphocyte proliferation in Hodgkin’s
lymphoma cell lines via apoptosis. In addition, lavender extracts and essential oil
exhibited cytotoxicity in malignant cells, upregulated Bax expression, induced PARP
cleavage in HeLa cells, and caused a sub-G1 peak in treated cells compared with
controls. Perillyl alcohol (POH), derived from botanicals including lavender, may
affect transforming growth factor-beta and/or Ras signaling pathways and Na/K-
ATPase inhibition.
Lavender oil has weak estrogenic and antiandrogenic activities that could potentially
alter estrogen and androgen signaling pathways.
Sources/Articles
Akhondzadeh S, Kashani L, Fotouhi A, Jarvandi S, Mobaseri M, Moin M et