Lavender

Scientific Name(s): Lavandula angustifolia Mill. (syn. Lavandula officinalis Chaix.) Lavandula stoechas L, Lavandula dentate , Lavandula latifolia Medik, Lavandula luisieri (Rozeira) Rivas Mart., and Lavandula pubescens Decne. Family: Lamiaceae (mints)

Common Name(s): Aspic , common lavender , English lavender , garden lavender , lavandin (usually refers to particular hybrids), lavender , pink lavender , spike lavender , true lavender , white lavender

Uses

Lavender has been used for restlessness, insomnia, anxiety, diabetes, GI distress, perineal discomfort following childbirth, chemoprevention, as an insect repellant, and as a food flavoring agent. However, there are limited clinical trials to support any therapeutic use for lavender.

Dosing

Aromatherapy for a bath: 6 drops (120 mg) added to 20 L of bath water , or 20 to 100 g of the dried herb in 20 L of bath water. , Inhalational aromatherapy: 2 to 4 drops in 2 to 3 cups (480 to 720 mL) of boiling water or used in an aromatic diffuser and inhaled. , Massage: 1 to 4 drops/Tbsp (15 mL) of base or carrier oil may be used or it may be mixed with other oils. , Tea: 1 to 2 tsp (5 to 10 mL) of lavender per cup (240 mL) of water. Oil for ingestion: 1 to 4 drops (20 mg to 80 mg), often given on a sugar cube.

Contraindications

Cautious use or avoidance is warranted in patients with known allergy/hypersensitivity to lavender.

Pregnancy/Lactation

Information regarding safety and efficacy in pregnancy and lactation is lacking. Lavender may possess emmenagogue properties, and excessive internal use should be avoided in pregnancy.

Interactions

CNS depressants and anticonvulsants may increase or potentiate narcotic and sedative effects when given in combination with lavender-containing products. Anticoagulants may increase the risk of bleeding when given concomitantly with lavender. Lavender may also cause additive cholesterol-lowering effects when given along with other drugs that lower cholesterol (eg, statins, nicotinic acid, fibric acid derivatives).

Adverse Reactions

Lavender may cause allergic contact dermatitis and photosensitization. Large oral doses have been associated with nausea, vomiting, and anorexia. Additionally, 3 case reports suggest a possible association between topical application of lavender and tea tree oils and prepubertal gynecomastia.

Toxicology

A case report describes an accidental ingestion of lavandin resulting in central nervous system depression in an 18-month-old child. The child's neurological state normalized within 6 hours of ingestion.

Botany

Lavender plants are aromatic evergreen sub-shrubs that grow to approximately 1 m high. The plants are native to the Mediterranean region, the Arabian peninsula, Russia, and Africa. Additionally, lavender is cultivated in the United States, the United Kingdom, southern Europe, and Australia. The many species readily hybridize with each other. Fresh flowering tops are collected, and the essential oil is distilled or extracts are obtained by solvent extraction. The plant has small blue or purple flowers. The narrow leaves are fuzzy and gray when young and turn green as they mature. Lavender is cultivated extensively for use as a perfume, potpourri, and as an ornamental plant. Lavender grows in a wide range of environments but grows best in full sun exposure. To obtain high yields of oils from lavender, it is necessary to prune the woody stocks each year in order to cause the shoots to bloom.

History

Lavender has long been used as an analgesic, antibacterial agent, antifungal agent, antidepressant, antispasmodic, carminative, cicatrizant, and sedative. Extracts have been used to treat conditions ranging from acne to migraines. The term Lavandula comes from the Latin word lavare , which means "to wash," suggesting its use as an antiseptic and disinfectant. Lavender was used in India and Tibet to treat psychiatric conditions and by the ancient Egyptians as part of the mummification process. In sixteenth century Europe, lavender skullcaps were thought to increase intelligence.

Although the plant has been known to increase bile flow output and flow into the intestine, its greatest value is not in the treatment of biliary conditions. Lavender has been used extensively as an antidiabetic agent in Spain and is included in some commercial herbal antidiabetic preparations. Fresh leaves and flowers are applied to the forehead to relieve headaches and to joints to treat rheumatic pain. The vapors of steamed flowers are used as a cold remedy. In Chile, the tea is used to induce or increase menstrual flow.

Lavender is usually administered in the form of an infusion, decoction, or oil and is either taken internally or applied topically for relief of neuralgia. Today, lavender oil and extracts are used as pharmaceutical fragrances and found in cosmetics. Spike lavender oil is often used in toiletry soaps because it is inexpensive but of lower quality than true lavender oil. Lavandin oil, lavender absolute (an extract), and spike lavender oil are used in concentrations of up to 1.2% in perfumes. Small amounts (0.002% to 0.004%) of the oil are used to flavor food. Lavender is also used in other bath and shower products, hair care products, and detergents.

Chemistry

Lavender flowers contain between 1% and 3% essential oil. The essential oil contains mixtures of mono- and sesquiterpenoid alcohols, esters, oxides, and ketones, the most abundant of which are linaloyl acetate (30% to 55%), linalool (20% to 35%), cineole, camphor, beta-ocimene, limonene, caproic acid, caryophyllene oxide, and tannins (5% to 10%). , , However, the relative amounts of these compounds can vary widely between species. , Lavandin hybrids contain a higher volatile oil content, but its composition is extremely variable. Additionally, lavandin oils are typically not used for cosmetic or therapeutic purposes because they contain high levels of camphor. Perillyl alcohol, a constituent of L. angustifolia , has been shown to exert anticancer effects. Several articles on lavender are available, discussing analysis methods, , , enantiomeric purity and distinctiveness, , , variety deviation, , , , essential oil quality, , gas chromatography retention indices, and lavender content in perfumes.

Uses and Pharmacology

Calming effects (aromatherapy, insomnia, spasmolytic and anxiolytic effects)

Lavender aromatherapy has been utilized to increase mental capacity and diminish fatigue, and to improve mood and perceived levels of anxiety. Oils of different lavender species yield different results. The German Commission E Monographs list treatment of restlessness and difficulties in sleeping among lavender's uses. Lavender electroencephalogram studies, which have shown various alpha wave responses to different odors, can be used for psychophysiological response evaluation. It has been suggested that lavender possesses similar action to the benzodiazepines by affecting gamma-aminobutyric acid receptors.

Animal data

Spike lavender oil has a spasmolytic effect on animal smooth muscle. These effects are consistent with the pharmacologic activities of many other common volatile oils. In mice, lavender oil exhibits CNS depressant activity, characterized by anticonvulsant activity and a potentiation of chloral hydrate-induced sleep. Another report on aromatherapy finds exposure time-dependent decreases in motility in mice after inhalation of lavender fragrance. This helps to confirm folk remedies such as herbal pillows used to facilitate rest or minimize stress in people. Additionally, lavender oil caused a reduction in hyperactivity following injection of caffeine in mice.

In a systematic review of aromatherapy in animal models, 4 of 5 studies identified positive anxiolytic effects with the use of lavender oil as evidenced with effects in 3 species of rodents. The effects were not limited to a particular species, dosage method, or animal model.

Clinical data

One report investigated the effects of lavender oil aromatherapy for insomnia and concluded that it is comparable with hypnotics or tranquilizers. A study of percutaneous absorption of lavender oil in massage found that within 5 minutes after application, the main constituents of the oil were detected in blood. After this rapid absorption, most of the lavender oil was excreted within 90 minutes. In patients with generalized anxiety disorder, the effects of Silexan , an oral lavender oil capsule, were compared with lorazepam over a period of 6 weeks. Silexan reduced the Hamilton Anxiety Rating Scale (HAM-A) by 11.3 ± 6.7 points (45%) compared with 11.6 ± 6.6 points (46%) with lorazepam. Other measures of anxiety were also noted with both treatment options. Silexan was not associated with sedation or has no potential for drug abuse. Thus, lavender may be an effective treatment option for patients suffering from generalized anxiety disorder.

In another clinical study, 221 adults with anxiety disorder were randomized to receive a 10-week treatment with Silexan or placebo 80 mg/day. The HAM-A score decreased by 16 ± 8.3 points (mean ± SD, 59.3%) and the Pittsburgh Sleep Quality Index decreased by 5.5 ± 4.4 points (44.7%) in those receiving Silexan compared with 9.5 ± 9.1 (35.4%) and 3.8 ± 4.1 points (30.9%) in the placebo group ( P < 0.01). No sedation was noted among participants receiving Silexan therapy.

In a study of healthy volunteers, the effects of oral lavender 100 and 200 mcL were compared with placebo following anxiety induction with the use of films/movies. The 200 mcL dose was associated with a greater reduction in self-reported anxiety from baseline as compared with placebo following observation of a neutral film. There were no differences between groups after viewing an anxiety-inducing film/movie. The investigators concluded that lavender may exert anxiolytic effects under low-anxiety conditions but not in high-anxiety conditions.

The level of anxiety was assessed in 340 dental patients while waiting for appointments either in the presence of lavender odor or none. Patients in the lavender group reported lower current anxiety levels than those in the control group.

A 30-minute aromatherapy massage with lavender oils (and other oils) twice a week for 4 weeks was associated with a reduction in anxiety in breast cancer patients who were from 6 months to over 3 years postoperation. Specifically, anxiety was reduced after 1 massage session, as measured by the State-Trait Anxiety Inventory test, and after 8 sessions, as measured by the Hospital Anxiety and Depression Scale test.

In an 8-week clinical study, the effects of aromatherapy massage on menopausal symptoms were assessed in 52 women. The participants were assigned to receive a 30-minute massage using essential oils (ie, lavender, rose geranium, rose and jasmine in almond and primrose oils) once weekly or no treatment. Menopausal symptoms such as hot flushes, melancholia, arthralgia, and myalgia were significantly lower in the experimental group compared with the control group ( P < 0.05 for all measures). Aromatherapy massage may be a potential treatment option for women suffering from menopausal symptoms.

The use of topical and inhalational lavender and ginger oils was associated with a lower mean distress level, as measured by the Faces, Legs, Arms, Cry and Consolability scale, in children in a perianesthesia setting; this finding was not statistically significant ( P < 0.055).

In a prospective, randomized, placebo-controlled clinical study, the effects of lavender aromatherapy on opioid requirement was assessed in 54 patients undergoing laparoscopic adjustable gastric banding. Analgesics were required in 82% of patients receiving placebo as compared with 46% in those receiving inhalational lavender ( P = 0.007). Additionally, significantly less morphine was required in those receiving lavender as compared with placebo (2.38 and 4.26 mg, respectively, P = 0.04). No differences between treatment groups were noted with respect to use of postoperative antiemetics, use of antihypertensives, or postanesthesia care unit discharge.

Aromatherapy massage with lavender oil was not associated with positive effects on sleep patterns (ie, sleep duration, time to fall asleep, number of awakenings) in 12 patients with autism. Though the massage fell within 2 hours of the children going to bed, closer control of the timing of the massage may be considered in future clinical studies.

In a study of 19 healthy medical personnel, the effect of inhaled lavender oil was assessed on endothelial function following night shift work. Flow mediated dilation (FMD) of the brachial artery was lower after night shift work, and FMD improved with lavender inhalation.

In 30 healthy men, inhalational lavender was associated with a reduction in serum cortisol levels (8.4 ± 3.6 mg/dL to 6.3 ± 3.3 mg/dL, P < 0.05), as well as an increase in coronary flow velocity reserve (3.8 ± 0.87 to 4.7 ±0.9, P < 0.001) following aromatherapy. However, this was not noted among the control group.

Twenty-eight patients with moderate-to-severe dementia were randomized to receive lavender aromatherapy 3 times daily for 1 hour after meals or placebo for 4 weeks. Neuropsychiatric Inventory scores significantly improved with lavender therapy (31 ± 10 to 18 ± 12, P < 0.01) and no significant changes were noted in the control group (32 ± 11 to 27 ± 12). In a randomized, crossover study, 70 Chinese adults with dementia were assigned to receive lavender inhalation for 3 weeks and then control for 3 weeks or vice versa. Agitation, aggressive behavior, irritability, and night-time behaviors were improved with lavender therapy. In another currently ongoing clinical study, the effects of topical lavender on behavioral symptoms associated with moderate-to-severe dementia in elderly patients residing in nursing facilities are being investigated further.

Hypoglycemic effects
Animal data

The infusion and suspension of L. stoechas causes hypoglycemia in normoglycemic rats, reaching maximum activity 30 minutes after administration. Further studies with L. dentata and L. latifolia have found the active hypoglycemic components to be partially water soluble. Furthermore, the extracts were not active in rats with alloxan-induced diabetes, indicating the need for intact pancreatic cells for a pharmacologic effect. The active components have not been chemically identified.

Clinical data

Research reveals no clinical data regarding the use of lavender for hypoglycemic effects.

GI disorders
Animal data

Research reveals no animal data regarding the use of lavender for GI disorders. In an in vitro model, L. angustifolia was found to inhibit the growth of organisms such as Bacteriodes fragilis , Candida albicans , and Clostridium spp. while sparing species of Lactobacillusi and Bifidobacterium , suggesting a possible role in the treatment of intestinal dysbiosis.

Clinical data

A Bulgarian report discusses choleretic and cholagogic action of Bulgarian lavender oil. Many volatile oils also may share these common actions. One of lavender's uses listed in the German Commission E Monographs is in functional disorders of the upper abdomen with irritable stomach and intestinal disorders of nervous origin. Its effects are both calming and antiflatulent.

Cancer chemoprevention

Perillyl alcohol, a compound distilled from lavender but also found in cherries, mint, and celery seeds, possesses anticancer activities. This monocyclic monoterpene is being tested in clinical trials to study its role in cancer chemoprevention and therapy. ,

A variety of mechanisms are proposed to explain perillyl alcohol's chemopreventative and chemotherapeutic effects. One such mechanism is that it promotes apoptosis. In 1 report, liver tumor formation was not promoted by perillyl alcohol, but its growth was inhibited by an apoptotic mechanism by enhancing tumor cell loss. In another report, the rate of apoptosis was more than 6-fold higher with perillyl alcohol-treated pancreatic adenocarcinoma cells than in untreated cells.

Another proposed mechanism of monoterpenes is inhibition of post-translational isoprenylation of cell growth-regulatory proteins (eg, Ras). Perillyl alcohol inhibited in vivo prenylation of specific proteins in one report and altered Ras protein synthesis and degradation in another. Interfering with these pathways can regulate malignant cell proliferation.

Animal data

Monoterpene-treated rat mammary tumors have been found to be remodeled and redifferentiated to more benign phenotypes. Perillyl alcohol treatment resulted in 70% to 99% inhibition of aberrant hyperproliferation, a late-occurring event preceding mammary tumorigenesis in vivo.

Other cancer models in which perillyl alcohol has been effective include murine melanoma growth suppression in vitro and in vivo, pancreatic carcinoma in hamsters, , colon carcinogenesis in rats, mammary cancer in rats, , liver tumors in rats, and lung cancer in rats.

However, 1 study in rats found 0.5% and 1% perillyl alcohol to weakly promote the growth of esophageal tumors.

Clinical data

In an in vitro model, data suggest that lavender oil is cytotoxic to human skin cells (ie, endothelial cells, fibroblasts).

Postnatal perineal discomfort
Animal data

Research reveals no animal data regarding the use of lavender for postnatal perineal discomfort.

Clinical data

A report evaluated the role of lavender oil as a bath additive to relieve perineal discomfort after childbirth. When compared with placebo and synthetic oil, analysis of daily discomfort scores show less discomfort between days 3 and 5 with true lavender oil use.

Antimicrobial effects
Animal data

In an in vitro study, direct contact with 4 lavender oils ( L. angustifolia , L. luisieri , L. latifolia , and L. stoechas ) was found to inhibit the growth of methicillin-sensitive and -resistant Staphylococcus aureus (MSSA and MRSA), with inhibition zones ranging from 8 to 30 mm with respective doses of 1 to 20 mcL. Larger inhibition zones were noted when L. luisieri was combined with L. stoechas and L. angustifolia . When exposed to the vapor phase of the lavender, MSSA and MRSA growth was not inhibited. Thus, these findings suggest potential antimicrobial properties associated with lavender.

Another in vitro study found lavender oil to exert antibacterial effects with particularly potent effects against gram-negative microorganisms.

Two essential oils derived from L. angustifolia and Lavandula intermedia were found to possess strong and rapid antiparasitic effects against Giardia duodenalis and Trichomonas vaginalis in an in vitro study. Additionally, the oils were associated with elimination of the fish pathogen, Hexamita inflata .

Another study found lavender oil and linalool to be effective against the growth of Candida albicans . Germ tube formation was also inhibited by the essential oil, linalool, and linalyl acetate. The investigators concluded that lavender oil was both fungistatic and fungicidal against C. albicans .

Clinical data

Forty-three patients with terminal cancer were assigned to oral treatment with essential oil (lavender, geranium, tea tree, peppermint) or control (0.9% saline) to be used twice daily for 1 week. Those receiving the essential oil preparation had fewer numbers of colonizing C. albicans as compared with the control group. Additionally, scores for subjective comfort and objective oral state were higher in the essential oil group as compared with the control group.

Other uses

Besides anticancer effects, perillyl alcohol has been used orally in rabbits to reduce vein graft intimal hyperplasia. It was also found to suppress hepatic 3-hydroxy-3-methylglutaryl-coenzymeA (HMG-CoA) reductase activity, a rate-limiting step in cholesterol synthesis, lowering serum cholesterol.

Lavandula hybrida given to mice in oral doses of 100 mg/kg or inhalation for 60 minutes was associated with protection against acute ethanol-induced gastric ulceration, but not against indomethacin-induced gastric ulceration.

An herbal extract ear drop containing lavender, among other ingredients, was found to reduce ear pain in children with acute otitis media.

Extracts of lavender are used in Europe as insect repellents. This effect appears to be related to compounds in the volatile oil. Findings from one study suggest that L. angustifolia is an effective method of controlling ticks.

A randomized, parallel study in 123 pediatric patients with head lice found that a tea tree/lavender oil product applied once weekly for 2 weeks on days 0, 7, and 14 was comparable in efficacy with a head lice suffocation product applied similarly. Both products were associated with a higher percentage of patients (97.6% for both groups) that were louse free 1 day after the last treatment as compared with subjects receiving pyrethrins and piperonyl butoxide applied twice on days 0 and 7 (25%, P < 0.0001 for both comparisons).

While not causing a direct analgesic effect, inhalational lavender was found to be associated with less pain intensity and pain unpleasantness as noted by a patient report in a model of experimentally induced pain.

In rats, inhaled lavender oil vapor was associated with anticonvulsive effects on pentetrazol, nicotine, and electroshock-induced convulsions but not strychnine-induced convulsions.

A study found the use of lavender useful to maintain attention spans during long-term tasks.

Lavender oil, in combination with other essential oils and salicyclic acid, may be a potential treatment option for patients with plantar warts.

Dosage

Aromatherapy for a bath

6 drops (120 mg) added to 20 L of bath water , ; 20 to 100 g of the dried herb in 20 L of bath water. ,

Inhalational aromatherapy

2 to 4 drops in 2 to 3 cups (480 to 720 mL) of boiling water, or use an aromatic diffuser and inhale. ,

Massage

1 to 4 drops/Tbsp (15 mL) of base or carrier oil; may mix with other oils. ,

Tea

1 to 2 tsp (5 to 10 mL) of lavender per cup of water.

Oil for ingestion

1 to 4 drops (20 mg to 80 mg), often given on a sugar cube.

Pregnancy/Lactation

Information regarding safety and efficacy in pregnancy and lactation is lacking. Lavender is believed to possess emmenagogue properties, and excessive internal use should be avoided in pregnancy.

Interactions

CNS depressants and anticonvulsants

May increase or potentiate narcotic and sedative effects when given in combination with lavender-containing products.

Anticoagulants

May increase the risk of bleeding when given concomitantly with lavender.

Cholesterol-lowering agents (eg, statins, nicotinic acid, fibric acid derivatives)

Lavender may cause additive cholesterol-lowering effects when given concomitantly with other drugs that lower cholesterol parameters.

Adverse Reactions

Lavender and lavandin oil have been reported to be nonirritating and nonsensitizing to human skin. However, 3 reports discuss allergic contact dermatitis from lavender oil and fragrance. , , These examples are few, probably because the oil is used in small quantities in foods and cosmetics and has not been associated with major toxicity during normal use. The German Commission E Monographs list no known adverse reactions or contraindications.

Three case reports describe the development of prepubertal gynecomastia following topical application of lavender and tea tree oils in a balm, styling gel, shampoo, soap, and lotion. The symptoms resolved within several months upon discontinuation. Investigators have found that lavender and tea tree oils demonstrated estrogenic and antiandrogenic effects on human cells lines.

Toxicology

Though not standardized in the United States, the US Food and Drug Administration considers lavender GRAS (generally recognized as safe) for consumption. Lavender oil exhibited a low order of toxicity when administered subcutaneously to animals. A case report describes toxicity occurring in an 18-month-old boy who unintentionally ingested homemade lavandin extract. Three hours later, he went into a state of confusion and presented to the hospital with CNS depression and a strong odor of lavender in his breath. An electroencephalogram found fast rhythm disorders. Six hours following the ingestion, his neurological state normalized. Headspace-gas chromatography-mass spectrometry confirmed linalyl acetate, linalyl formate, and acetone in the child's urine and blood.

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