A glass vial of lavender oil
A glass vial of lavender oil

Lavender oil is an essential oil obtained by distillation from the flower spikes of certain species of lavender. There are over 400 types of lavender worldwide with different scents and qualities. Two forms of lavender oil are distinguished, lavender flower oil, a colorless oil, insoluble in water, having a density of 0.885 g/mL; and lavender spike oil, a distillate from the herb Lavandula latifolia, having density 0.905 g/mL. Like all essential oils, it is not a pure compound; it is a complex mixture of phytochemicals, including linalool and linalyl acetate.

Production

Pure lavender essential oil is produced through steam distillation.[1][2] This generates a greater amount of oil compared to other methods due to reduction of polar compound loss.[3] Harvest of lavender blooms is typically between late June and August.[4] The cut lavender flowers and stems are compacted into a lavender still. A boiler is then used to steam the bottom of the lavender flower filled still at a very low pressure.[1] The lavender flower pockets containing oil are broken from this heating process and a pipe of cold water is run through the center of the still.[1] The hot lavender oil vapor condenses on the cold pipe with the cold water and is collected into a holding tank where it is allowed to settle.[1] Due to polarity and densities of the water and oil, these two will separate in the holding tank whereupon the water is piped out, leaving just lavender essential oil.[5]

Lavender oil is produced around the world, with Bulgaria, France and China leading its production.[6][7]

Uses

In the United States, lavender oil is Generally Recognized as Safe (GRAS) for its intended uses.[8] Lavender oil has been used as a perfume, aromatherapy, and skin applications,[9][10]: 184–186  but these uses have no clinical benefit.[11] Lavender oil is used in massage therapy as a way of inducing relaxation through direct skin contact,[9] although allergic reactions may occur.[11] There is no good evidence to support the use of lavender oil for treating dementia.[12]

A 2021 meta-analysis included five studies of people with anxiety disorders. All five studies were funded by the manufacturers of the lavender oil capsule used, four of them were conducted by one author of the meta-analysis,[13] and blinding was not clear.[14] In this analysis, an oral 80 mg dose of lavender oil per day was associated with reduced anxiety scores on the Hamilton Anxiety Rating Scale.[13] According to the National Center for Complementary and Integrative Health, the effectiveness of using oral lavender oil for treating anxiety remains undetermined due to the limitations of these studies.[11]

Oil of spike lavender was used as a solvent in oil painting, mainly before the use of distilled turpentine became common.[15]

Adverse effects

If ingested, lavender oil is poisonous in amounts as small as 5 millilitres (0.18 imp fl oz; 0.17 US fl oz) due to its constituents linalyl acetate and linalool.[16][17] Symptoms of lavender oil poisoning include blurred vision, difficulty breathing, burning pain in the throat, burns to the eye, confusion, decreased level of consciousness, diarrhea (watery, bloody), stomach pain, vomiting, and rash.[16] In Australia, lavender oil is one of several essential oils that may cause life-threatening toxicity after ingestion, especially in children.[17] Over 2014-2018, there were 271 reported cases in New South Wales, accounting for 6.1% of essential oil poisoning incidents.[17]

Lavender oil has estrogenic and anti-androgenic effects and there have been reports of its use causing prepubertal gynecomastia (abnormal breast development in children).[18][19] Other potential adverse effects include a sedative effect and contact dermatitis as an allergic reaction, possibly resulting from major lavender oil constituents, camphor, terpinen-4-ol, linalool and linalyl acetate.[9][20]

Ingestion of lavender oil may cause interactions with prescription drugs, including anticoagulants, statins, and anticonvulsants.[21]

Environmental impact

A 2018 study by the National Institute of Environmental Health Sciences found four of the constituent chemicals (eucalyptol, 4-terpineol, limonene and alpha-terpineol) are endocrine disruptors, raising concerns of potential environmental health impact from the oil.[22]

Phytochemicals

The phytochemical composition of lavender oil varies from species to species (table), consisting primarily of monoterpeneoid and sesquiterpeneoid alcohols.[21] Linalool (20-35%) and linalyl acetate (30-55%) dominate, with moderate levels of lavandulyl acetate, terpinen-4-ol and lavandulol, 1,8-cineole, camphor, limonene, and tannins.[21] Lavender oil typically contains more than 100 compounds, although many of these are at negligible concentrations.[21][23]

The composition of lavender essential oil as obtained by chromatography:[24]

Family Composition Lavande officinale
Lavandula angustifolia
Lavande aspic
Lavandula latifolia
Terpenes /
Monoterpenols
Linalool skeletal.svg

Linalool
28.92 % 49.47 %
α-Terpineol 0.90% 1.08%
γ-Terpineol 0.09%
Borneol 1.43%
Isoborneol 0.82%
Terpinen-4-ol 4.32%
Nerol 0.20%
Lavandulol 0.78%
Terpenes /
Terpene esters
Linalyl acetate.svg
Linalyl acetate
32.98 %
Geranyl acetate 0.60%
Neryl acetate 0.32%
Octene-3-yl acetate 0.65%
Lavandulyl acetate 4.52%
Terpenes /
Monoterpenes
Myrcene 0.46% 0.41%
α-Pinene 0.54%
β-Pinene 0.33%
Camphene 0.30%
(E)-β-Ocimene 3.09%
(Z)-β-Ocimene 4.44%
β-Phellandrene 0.12%
Terpenes /
Terpenoid oxides
Eucalyptol.png

Eucalyptol
(1,8-cineol)
25.91 %
Terpenes /
Sesquiterpenes
β-Caryophyllene 4.62% 2.10%
β-Farnesene 2.73%
Germacrene 0.27%
α-Humulene 0.28%
Ketones
Camphor structure.png

Camphor
0.85% 13.00 %
3-Octanone 0.72%
Cryptone.svg

Cryptone
0.35%

References

  1. ^ a b c d Lis-Balchin, Maria (August 2002). Lavender: The Genus Lavandula. CRC Press. ISBN 978-0-203-21652-1.
  2. ^ Health (U.S.), National Institute of (1919). Digest of Comments on The Pharmacopœia of the United States of America and on the National Formulary for the Calendar Year ... 1905-1922. U.S. Government Printing Office.
  3. ^ Masango P (2005-06-01). "Cleaner production of essential oils by steam distillation". Journal of Cleaner Production. 13 (8): 833–839. doi:10.1016/j.jclepro.2004.02.039. ISSN 0959-6526.
  4. ^ Simmons, Adelma Grenier (1989). Country wreaths from Caprilands: the legend, lore, and design of traditional herbal wreaths. Rodale Press. ISBN 978-0-87857-792-7.
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  7. ^ Giray, Handan (November 2018). "An Analysis of World Lavender Oil Markets and Lessons for Turkey". Journal of Essential Oil-bearing Plants. 21 (6): 1612–1623. doi:10.1080/0972060X.2019.1574612. S2CID 107300743.
  8. ^ "Sec. 182.20 Essential oils, oleoresins (solvent-free), and natural extractives (including distillates)". FDA. Retrieved 24 March 2022.
  9. ^ a b c Sarkic A, Stappen I (12 January 2018). "Essential oils and their single compounds in cosmetics: A critical review". Cosmetics. 5 (1): 11. doi:10.3390/cosmetics5010011. ISSN 2079-9284.
  10. ^ Groom N (1997). The New Perfume Handbook (2nd ed.). Blackie Academic & Professional. ISBN 978-0-7514-0403-6.
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  12. ^ Ball EL, Owen-Booth B, Gray A, Shenkin SD, Hewitt J, McCleery J (August 2020). "Aromatherapy for dementia". Cochrane Database of Systematic Reviews (Meta-analysis). 8: CD003150. doi:10.1002/14651858.CD003150.pub3. PMC 7437395. PMID 32813272.
  13. ^ a b von Känel, Roland; Kasper, Siegfried; Bondolfi, Guido; et al. (2021-04-11). "Therapeutic effects of Silexan on somatic symptoms and physical health in patients with anxiety disorders: A meta-analysis". Brain and Behavior. 11 (4): e01997. doi:10.1002/brb3.1997. ISSN 2162-3279. PMC 8035468. PMID 33638614.
  14. ^ Generoso, Marcelo B.; Soares, Amanda; Taiar, Ivan T.; Cordeiro, Quirino; Shiozawa, Pedro (2017). "Lavender Oil Preparation (Silexan) for Treating Anxiety". Journal of Clinical Psychopharmacology. 37 (1): 115–117. doi:10.1097/jcp.0000000000000615. ISSN 1533-712X. PMID 27861196. S2CID 42697028.
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  16. ^ a b "Lavender oil". MedlinePlus. U.S. National Library of Medicine, U.S. Department of Health and Human Services. Retrieved January 9, 2020. Poisonous Ingredient: It is mainly the linalyl acetate and linalool in lavender oil that are poisonous.
  17. ^ a b c Lee KA, Harnett JE, Cairns R (November 2019). "Essential oil exposures in Australia: analysis of cases reported to the NSW Poisons Information Centre". The Medical Journal of Australia. 212 (3): 132–133. doi:10.5694/mja2.50403. PMID 31709543. S2CID 207940224.
  18. ^ Poon SW, Siu KK, Tsang AM (October 2020). "Isoniazid-induced gynaecomastia: report of a paediatric case and review of literature". BMC Endocrine Disorders (Review). 20 (1): 160. doi:10.1186/s12902-020-00639-9. PMC 7590456. PMID 33109161.
  19. ^ Restrepo R, Cervantes LF, Swirsky AM, Diaz A (October 2021). "Breast development in pediatric patients from birth to puberty: physiology, pathology and imaging correlation". Pediatr Radiol (Review). 51 (11): 1959–1969. doi:10.1007/s00247-021-05099-4. PMID 34236480. S2CID 235767694.
  20. ^ Elshafie HS, Camele I (5 November 2017). "An Overview of the Biological Effects of Some Mediterranean Essential Oils on Human Health". BioMed Research International. 2017: 9268468. doi:10.1155/2017/9268468. PMC 5694587. PMID 29230418.
  21. ^ a b c d "Lavender". Drugs.com. 22 October 2021. Retrieved 25 May 2022.
  22. ^ "Chemicals in lavender and tea tree oil appear to be hormone disruptors". Endocrine Society. 19 March 2018.
  23. ^ Shellie R, Mondello L, Marriott P, Dugo G (September 2002). "Characterisation of lavender essential oils by using gas chromatography-mass spectrometry with correlation of linear retention indices and comparison with comprehensive two-dimensional gas chromatography". Journal of Chromatography A. 970 (1–2): 225–34. doi:10.1016/S0021-9673(02)00653-2. PMID 12350096.
  24. ^ Marincaş, Olivian; Feher, Ioana (2018-12-01). "A new cost-effective approach for lavender essential oils quality assessment". Industrial Crops and Products. 125: 241–247. doi:10.1016/j.indcrop.2018.09.010. ISSN 0926-6690. S2CID 104553013.