Chemistry: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 a density of 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
Lavender oil has been used as a perfume, aromatherapy, and skin application,[8]:184–186 but these uses have no clinical benefit.[9] Lavender oil is used in massage therapy as a way of inducing relaxation through direct skin contact, although allergic reactions may occur.[9] There is no good evidence to support the use of lavender oil for treating dementia.[10]
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,[11] and blinding was not clear.[12] 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.[11] 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.[9]
Oil of spike lavender was used as a solvent in oil painting, mainly before the use of distilled turpentine became common.[13]
Possible adverse effects
Although lavender oil is generally recognized as safe for its intended uses,[14] it is a potential endocrine disruptor that may affect breast development in children.[15]
Many essential oils, including lavender oil, can be poisonous if swallowed.[16][17] In general, 5 millilitres (0.17 US fl oz) of a diluted essential oil may cause toxicity in adults, whereas 2–3 millilitres (0.068–0.101 US fl oz) can be toxic in children.[18] Over 2014-18 in New South Wales, there were 271 reported cases of lavender oil poisoning – mostly in children – accounting for 6.1% of all essential oil poisoning cases.[17] The main toxic constituents of lavender oil are linalyl acetate and linalool.[16][19]
Symptoms of lavender oil poisoning by ingestion include blurred vision, difficulty breathing, burning pain in the throat, burns to the eye, confusion, decreased level of consciousness, diarrhea, stomach pain, vomiting, and rash.[16] Topical application of lavender oil may cause contact dermatitis.[18]
Ingestion of lavender oil may cause interactions with prescription drugs, including anticoagulants, statins, and anticonvulsants.[20]
Phytochemicals
The phytochemical composition of lavender oil varies from species to species (table), consisting primarily of monoterpeneoid and sesquiterpeneoid alcohols.[20] 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.[20] Lavender oil typically contains more than 100 compounds, although many of these are at negligible concentrations.[20][21]
The composition of lavender essential oil as obtained by chromatography:[22]
| Family | Composition | Lavande officinale Lavandula angustifolia |
Lavande aspic Lavandula latifolia |
|---|---|---|---|
| Terpenes / Monoterpenols |
 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 |
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 (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 |
0.85% | 13.00 % |
| 3-Octanone | 0.72% | ||
 Cryptone |
0.35% |
References
- ↑ 1.0 1.1 1.2 1.3 Lis-Balchin, Maria (August 2002) (in en). Lavender: The Genus Lavandula. CRC Press. ISBN 978-0-203-21652-1. https://books.google.com/books?id=TmvkY60iESkC&q=lavender+still+steam&pg=PA106.
- ↑ Health (U.S.), National Institute of (1919) (in en). 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. https://books.google.com/books?id=sfFReCRbKs8C&q=lavender+oil+steam+distillation&pg=PA345.
- ↑ Masango, Phineas (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.
- ↑ Simmons, Adelma Grenier (1989) (in en). Country wreaths from Caprilands: the legend, lore, and design of traditional herbal wreaths. Rodale Press. ISBN 978-0-87857-792-7. https://books.google.com/books?id=lT_o0nNL1LgC&q=lavender+june+harvest.
- ↑ "Influence of oil polarity on droplet growth in oil-in-water emulsions stabilized by a weakly adsorbing biopolymer or a nonionic surfactant". Journal of Colloid and Interface Science 247 (1): 167–76. March 2002. doi:10.1006/jcis.2001.8110. PMID 16290453. Bibcode: 2002JCIS..247..167C.
- ↑ Mihala, Lorelei (2020-07-30). "Bulgarian lavender: The sweet smell of success" (in en-GB). BBC News. https://www.bbc.com/news/business-53493550.
- ↑ 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. https://www.researchgate.net/publication/331664982.
- ↑ The New Perfume Handbook (2nd ed.). Blackie Academic & Professional. 1997. ISBN 978-0-7514-0403-6.
- ↑ 9.0 9.1 9.2 "Lavender". National Center for Complementary and Integrative Health, US National Institutes of Health. 1 August 2020. https://www.nccih.nih.gov/health/lavender.
- ↑ "Aromatherapy for dementia". Cochrane Database of Systematic Reviews 2020 (8): CD003150. August 2020. doi:10.1002/14651858.CD003150.pub3. PMID 32813272.
- ↑ 11.0 11.1 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. PMID 33638614.
- ↑ 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.
- ↑ The Grove encyclopedia of materials and techniques in art. Oxford University Press. 2008. pp. 605–606. ISBN 978-0-19-531391-8.
- ↑ "Sec. 182.20 Essential oils, oleoresins (solvent-free), and natural extractives (including distillates)". FDA. https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/cfrsearch.cfm?fr=182.20.
- ↑ "Endocrine disruptors" (in en). National Institute of Environmental Health Sciences, US National Institutes of Health. 2 June 2023. https://www.niehs.nih.gov/health/topics/agents/endocrine/index.cfm.
- ↑ 16.0 16.1 16.2 "Lavender oil". MedlinePlus, National Library of Medicine, US National Institutes of Health. 13 November 2021. https://medlineplus.gov/ency/article/002711.htm. "Poisonous ingredient: It is mainly the linalyl acetate and linalool in lavender oil that are poisonous."
- ↑ 17.0 17.1 "Essential oil exposures in Australia: analysis of cases reported to the NSW Poisons Information Centre". The Medical Journal of Australia 212 (3): 132–133. November 2019. doi:10.5694/mja2.50403. PMID 31709543. "We found that essential oil exposures are frequent in Australia, and that more than half involve children. ... severe toxicity can be caused by as little as 5 mL".
- ↑ 18.0 18.1 "Essential oil poisoning". Royal Children's Hospital, Melbourne, Australia. July 2021. https://www.rch.org.au/clinicalguide/guideline_index/Essential_Oil_Poisoning/. "Volumes of 5-15 mL are likely to cause toxicity in adults"
- ↑ "An overview of the biological effects of some Mediterranean essential oils on human health". BioMed Research International 2017: 9268468. 5 November 2017. doi:10.1155/2017/9268468. PMID 29230418.
- ↑ 20.0 20.1 20.2 20.3 "Lavender". Drugs.com. 22 October 2021. https://www.drugs.com/npp/lavender.html.
- ↑ "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. September 2002. doi:10.1016/S0021-9673(02)00653-2. PMID 12350096.
- ↑ Marincaş, Olivian; Feher, Ioana (2018-12-01). "A new cost-effective approach for lavender essential oils quality assessment" (in en). Industrial Crops and Products 125: 241–247. doi:10.1016/j.indcrop.2018.09.010. ISSN 0926-6690. https://www.sciencedirect.com/science/article/pii/S0926669018308082.
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