imported>Howard C. Berkowitz |
imported>Howard C. Berkowitz |
| Line 70: |
Line 70: |
| Interest in essential oils has revived in recent decades, with the popularity of [[aromatherapy]], a branch of [[alternative medicine]] which claims that the specific aromas carried by essential oils have curative effects. Oils are volatilized or diluted in a carrier oil and used in massage, or burned as incense, for example.--> | | Interest in essential oils has revived in recent decades, with the popularity of [[aromatherapy]], a branch of [[alternative medicine]] which claims that the specific aromas carried by essential oils have curative effects. Oils are volatilized or diluted in a carrier oil and used in massage, or burned as incense, for example.--> |
|
| |
|
| == Production ==
| |
| {{main|Extraction (fragrance)}}
| |
|
| |
| ===Distillation===
| |
| {{see also|Distillation}}
| |
| Some common essential oils, such as [[lavender]], [[peppermint]], [[tea-tree]] and [[eucalyptus]], are distilled. Raw plant material, consisting of the [[flower]]s, [[leaf|leaves]], [[wood]], [[bark]], [[root]]s, [[seed]]s, or [[peel (fruit)|peel]], is put into an [[alembic]] (distillation apparatus) over [[water]]. As the water is heated the steam passes through the plant material, vaporizing the volatile compounds. The vapors flow through a coil where they condense back to liquid, which is then collected in the receiving vessel.
| |
|
| |
|
| <!--
| |
| Most oils are distilled in a single process. One exception is [[Ylang-ylang]] ([[Cananga odorata]]), which takes 22 hours to complete through a [[Fractional distillation | fractional distillation]].
| |
|
| |
| The water recondensed from the distillation process is referred to as a [[hydrosol]], hydrolat, [[herbal distillate]] or plant water essence, which may be sold as another fragrant product. Popular hydrosols are [[rose water]], [[lavender water]], [[lemon balm]], [[clary sage]] and [[orange blossom water]]. The use of herbal distillates in [[cosmetics]] is increasing. Some plant hydrosols have unpleasant [[smell]]s and are therefore not sold.
| |
|
| |
| ===Expression===
| |
| Most citrus peel oils are usually expressed mechanically, or ''[[cold-pressed]]''. Due to the large quantities of oil in citrus peel and the relatively low cost to grow and harvest the raw materials, citrus-fruit oils are cheaper than most other essential oils. Lemon or sweet orange oils that are obtained as [[by-product]]s of the commercial citrus industry are even cheaper.
| |
|
| |
| Prior to the discovery of [[distillation]], some essential oils (EO) were extracted by pressing.
| |
|
| |
| ===Solvent extraction===
| |
| Most flowers contain very little volatile oil to undergo expression and their chemical components are too delicate and easily denatured by the high heat used in steam distillation. Instead, a [[solvent]] such as [[hexane]] or [[supercritical carbon dioxide]] is used to extract the oils. Extracts from hexane and other hydrophobic solvent are called ''[[Concrete (perfumery)|concrete]]s'', which is mixture of essential oil, waxes, resins, and other [[lipophilic]] (oil soluble) plant material.
| |
|
| |
| Although highly fragrant, concretes contain large quantities of non-fragrant waxes and resins. As such another solvent, often [[ethanol|ethyl alcohol]], which only dissolves the fragrant low-molecular weight compounds, is used to extract the fragrant oil from the concrete. The alcohol is removed by a second distillation, leaving behind the ''[[Absolute (substance)|absolute]]''.
| |
|
| |
| [[Supercritical carbon dioxide]] is used as a solvent in supercritical fluid extraction. This method has many benefits, including avoiding [[petrochemical]] residues in the product. It does not yield an absolute directly. The supercritical carbon dioxide will extract both the waxes and the essential oils that make up the concrete. Subsequent processing with liquid carbon dioxide, achieved in the same extractor by merely lowering the extraction temperature, will separate the waxes from the essential oils. This lower temperature process prevents the decomposition and denaturing of compounds and provides for a superior product. When the extraction is complete, the pressure is reduced to ambient and the carbon dioxide reverts back to a gas, leaving no residue. Although supercritical carbon dioxide is also used for making [[decaffeinated]] [[coffee]], the actual process is different.
| |
|
| |
| ===Production quantities===
| |
|
| |
| Estimates of total production of essential oils are difficult to obtain. One estimate, compiled from data in 1989, 1990 and 1994 from various sources gives the following total production, in tonnes, of essential oils for which more than 1,000 tonnes were produced.<ref>{{cite web
| |
| | url=http://isotc.iso.org/livelink/livelink/971087/ISO_TC_054__Essential_oils_.pdf
| |
| | title=ISO TC 54 Business Plan — Essential oils
| |
| | accessdate=2006-09-14
| |
| }} It is unclear from the source what period of time the quoted figures include.</ref>
| |
|
| |
| :{| class="wikitable"
| |
| ! Oil !! Tonnes
| |
| |-
| |
| | [[Sweet orange]] || align="right" | 12,000
| |
| |-
| |
| | ''[[Mentha arvensis]]'' || align="right" | 4,800
| |
| |-
| |
| | [[Peppermint]] || align="right" | 3,200
| |
| |-
| |
| | [[Cedar|Cedarwood]] || align="right" | 2,600
| |
| |-
| |
| | [[Lemon]] || align="right" | 2,300
| |
| |-
| |
| | ''[[Eucalyptus globulus]]'' || align="right" | 2,070
| |
| |-
| |
| | ''[[Litsea cubeba]]'' || align="right" | 2,000
| |
| |-
| |
| | [[Clove]] (leaf) || align="right" | 2,000
| |
| |-
| |
| | [[Spearmint]] || align="right" | 1,300
| |
| |}
| |
| -->
| |
| <!--
| |
| ==Aromatherapy==
| |
| {{main|Aromatherapy}} -->
| |
| <!--
| |
| Aromatherapy is a form of [[alternative medicine]], in which healing effects are ascribed to the aromatic compounds in essential oils and other plant extracts. Many common essential oils have medicinal properties that have been applied in [[folk medicine]] since ancient times and are still widely used today. For example, many essential oils have [[antiseptic]] properties, though some are stronger than others.<ref>{{cite journal
| |
| | url=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&rendertype=abstract&artid=1693916
| |
| | title=In vitro antibacterial activity of some plant essential oils
| |
| | author=Seenivasan Prabuseenivasan, Manickkam Jayakumar, and Savarimuthu Ignacimuthu
| |
| | journal=BMC Complement Altern Med.
| |
| | date=November 30, 2006
| |
| | volume=6
| |
| | issue=39
| |
| | id=DOI 10.1186/1472-6882-6-39
| |
| | accessdate=2006-12-22
| |
| }}</ref>. In addition, many are claimed to have an uplifting effect on the mind, though different essential oils have different properties. The claims are supported in some studies<ref>{{cite journal
| |
| | url=http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=AbstractPlus&list_uids=16780969&query_hl=8&itool=pubmed_docsum
| |
| | title=Lemon oil vapor causes an anti-stress effect via modulating the 5-HT and DA activities in mice
| |
| | author=Komiya M, Takeuchi T, Harada E
| |
| | journal=Behav Brain Res
| |
| | date=September 25, 2006
| |
| | volume=172
| |
| | issue=2
| |
| | pages=240-9
| |
| | accessdate=2006-12-24
| |
| | id=PMID 16780969
| |
| }}</ref><ref>{{cite journal
| |
| | url=http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=AbstractPlus&list_uids=16095639&query_hl=8&itool=pubmed_docsum
| |
| | title=Ambient odors of orange and lavender reduce anxiety and improve mood in a dental office
| |
| | author=Hiroko Kuriyama, Satoko Watanabe, Takaaki Nakaya, Ichiro Shigemori, Masakazu Kita, Noriko Yoshida, Daiki Masaki, Toshiaki Tadai, Kotaro Ozasa, Kenji Fukui, and Jiro Imanishi
| |
| | journal=Physiol Behav
| |
| | date=September 15, 2005
| |
| | volume=86
| |
| | issue=1-2
| |
| | pages=92-5
| |
| | accessdate-2006-12-24
| |
| | id=PMID 16095639
| |
| }}</ref> and unconfirmed in others.
| |
|
| |
| Skin application, not necessarily massage, have been tested as more effective than inhalation alone. Another study suggested that applying the oils to the skin may be more effective than inhalation. <ref name=>{{citation
| |
| | journal = Altern Complement Med
| |
| | date = 2004 Jun
| |
| | volume = 10(3)
| |
| | pages =431-7.
| |
| | title= A controlled trial of aromatherapy for agitation in nursing home patients with dementia.
| |
| | author = Snow LA, Hovanec L, Brandt J. | url = http://www.ncbi.nlm.nih.gov/pubmed/15253846}}</ref> Massage may be of greater benefit than either inhalation or simple application. <ref>{{cite journal
| |
| | url=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&rendertype=abstract&artid=1142199
| |
| | title=Immunological and Psychological Benefits of Aromatherapy Massage
| |
| | journal=Evid Based Complement Alternat Med
| |
| | author=Lehrner J, Marwinski G, Lehr S, Johren P, Deecke L
| |
| | volume=2
| |
| | issue=2
| |
| | date=June 2005
| |
| | accessdate=2006-12-24
| |
| | doi=10.1093/ecam/neh087
| |
| }}</ref>
| |
| == Dilution ==
| |
|
| |
| Essential oils are usually [[lipophilic]] (literally: ''"oil-loving"'') compounds that usually are not [[miscible]] with water. Instead, they can be diluted in [[solvent]]s like pure 100% [[ethanol]] (''alcohol''), [[polyethylene glycol]], or [[oil]]s.
| |
| -->
| |
|
| |
|
| == Raw materials == | | == Raw materials == |
The American Heritage Dictionary defines essential oil as:
A volatile oil, usually having the characteristic odor or flavor of the plant from which it is obtained, used to make perfumes and flavorings.[1]
Familiar examples of essential oils include those extracted from species of citrus, lavender, seeds of celery and pumpkin, eucalyptus, and rosewood.
In addition to their use in perfumes and flavorings, essential oils have been used in complementary and alternative medicine as antimicrobials. Microbiologists Hammer and colleagues studied the in vitro antimicrobial activity of 52 essential oils, reporting as follows:
In summary, this study confirms that many essential oils and plant extracts possess in vitro antibacterial and antifungal activity. However, if plant oils and extracts are to be used for food preservation or medicinal purposes, issues of safety and toxicity will need to be addressed.[2]
Aromatherapy
The odoriferous quality of essential oils lends itself to the practice called aromatherapy, wherein the inhalation of the odors of an oil may yield positive health effects of various types. In some respects, assessing its benefits are more difficult than with other forms of complementary medicine: whether or not the essential oils actually give benefit, they smell much better than the average hospital.
Uses
Some of the clinical trials that are more suggestive of benefits have two characteristics:
- Aromatherapy is complementary to medical therapy[3]
- Aromatherapy is complementary to other complementary therapies: it may, for example, be effective in combination with massage but not on its own.[4]
Training in aromatherapy does not convey additional diagnostic skill. [5]
The National Cancer Institute (NCI), linked through the National Center for Complementary and Alternative Medicine (NCCAAM), provides the following overview of aromatherapy for health professional:
- Aromatherapy is the therapeutic use of essential oils (also known as volatile oils) from plants (flowers, herbs, or trees) for the improvement of physical, emotional, and spiritual well-being.
- Aromatherapy is used by patients with cancer primarily as supportive care for general well-being.
- Aromatherapy is used with other complementary treatments (e.g., massage and acupuncture) as well as standard treatment.
- Essential oils are volatile liquid substances extracted from aromatic plant material by steam distillation or mechanical expression; oils produced with the aid of chemical solvents are not considered true essential oils.
- Essential oils are available in the United States for inhalation and topical treatment. Topical treatments are generally used in diluted forms.
- Aromatherapy is not widely administered via ingestion.
- The effects of aromatherapy are theorized to result from the effect of odorant molecules from essential oils on the brain’s emotional center, the limbic system. Topical application of aromatic oils may exert antibacterial, anti-inflammatory, and analgesic effects.
- Studies in animals show sedative and stimulant effects of specific essential oils as well as positive effects on behavior and the immune system. Functional imaging studies in humans support the influence of odors on the limbic system and its emotional pathways.
- Human clinical trials have investigated aromatherapy primarily in the treatment of stress and anxiety in patients with critical illnesses or in other hospitalized patients. Several clinical trials involving patients with cancer have been published.
- Aromatherapy has a relatively low toxicity profile when administered by inhalation or diluted topical application.
- Aromatherapy products do not need approval by the U.S. Food and Drug Administration because there is no claim for treatment of specific diseases.
- Repeated exposure to lavender and tea tree oils by topical administration has been associated with reversible prepubertal gynecomastia.
Raw materials
- For more information, see: List of essential oils.
References
- ↑ The American Heritage® Dictionary of the English Language, Fourth Edition. Copyright© 2006, 2000 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
- ↑ Hammer KA, Carson CF, Riley TV. (1999) Antimicrobial activity of essential oils and other plant extracts. J Appl Microbiol 86:985-90. PMID 10438227
- ↑ Caroline Hoffman (20 December 2007), "Benefits of complementary therapies", Breast Cancer Res. 9(Suppl 2): S9., DOI:10.1186/bcr1807.
- ↑ Susie M. Wilkinson, Sharon B. Love, Alex M. Westcombe, Maureen A. Gambles, Caroline C. Burgess, Anna Cargill, Teresa Young, E. Jane Maher, Amanda J. Ramirez (10 February 2007), "Effectiveness of Aromatherapy Massage in the Management of Anxiety and Depression in Patients With Cancer: A Multicenter Randomized Controlled Trial", Journal of Clinical Oncology 25 (5): 532-539, DOI:10.1200/JCO.2006.08.9987
- ↑ Select Committee appointed to consider Science and Technology, U.K. Parliament (21 November 2000), Chapter 2: Disciplines examined, Definitions of the Various CAM Therapies, Complementary and Alternative Medicine
