Essential oil
Plant oils |
---|
Types |
|
Uses |
Components |
An essential oil is a concentrated
Essential oils are generally extracted by
Essential oils are often used for aromatherapy, a form of alternative medicine in which healing effects are ascribed to aromatic compounds. Aromatherapy may be useful to induce relaxation, but there is not sufficient evidence that essential oils can effectively treat any condition.[3] Improper use of essential oils may cause harm including allergic reactions, inflammation and skin irritation. Children may be particularly susceptible to the toxic effects of improper use.[4][5] Essential oils can be poisonous if ingested or absorbed through the skin.[5]
Production
Distillation
Most common essential oils such as lavender, peppermint, tea tree oil, patchouli, and eucalyptus are distilled. Raw plant material, consisting of the flowers, leaves, wood, bark, roots, seeds, or 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 is purified through a fractional distillation.
The recondensed water is referred to as a hydrosol, hydrolat,
Expression
Most
Before the discovery of distillation, all essential oils were extracted by pressing.[7]
Solvent extraction
Most flowers contain too little volatile oil to undergo expression, but their chemical components are too delicate and easily denatured by the high heat used in steam distillation. Instead, a
Although highly fragrant, concretes contain large quantities of non-fragrant waxes and resins. Often, another solvent, such as
Supercritical carbon dioxide is used as a solvent in supercritical fluid extraction. This method can avoid petrochemical residues in the product and the loss of some "top notes" when steam distillation is used. 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. When the extraction is complete, the pressure is reduced to ambient and the carbon dioxide reverts to a gas, leaving no residue.
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.[9]
Oil Tonnes Sweet orange 12,000 Mentha arvensis 4,800 Peppermint 3,200 Cedarwood 2,600 Lemon 2,300 Eucalyptus globulus 2,070 Litsea cubeba 2,000 Clove (leaf) 2,000 Spearmint 1,300
Uses and cautions
This section needs more primary sources. (September 2010) |
Taken by mouth, many essential oils can be dangerous in high concentrations. Typical effects begin with a burning feeling, followed by salivation.
In Australia essential oils (mainly eucalyptus) have been increasingly causing cases of poisoning, mostly of children. In the period 2014–2018 there were 4,412 poisoning incidents reported in New South Wales.[16]
Use in 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. Aromatherapy may be useful to induce relaxation, but there is not sufficient evidence that essential oils can effectively treat any condition.[3] Scientific research indicates that essential oils cannot treat or cure any chronic disease or other illnesses.[3] Much of the research on the use of essential oils for health purposes has serious methodological errors. In a systemic review of 201 published studies on essential oils as alternative medicines, only 10 were found to be of acceptable methodological quality, and even these 10 were still weak in reference to scientific standards.[3] Use of essential oils may cause harm including allergic reactions and skin irritation; After receiving a facial at an all-natural salon, a person experienced severe skin irritation, which highlighted the potential dangers of using "clean" beauty products marketed as being made from natural ingredients. This incident underscores the misconception that natural compounds are always safe, revealing a growing awareness within the beauty industry about the risks associated with essential oils, which can lead to allergic reactions and skin damage;[18] there has been at least one case of death.[4]
Use as pesticide
Research has shown that some essential oils have potential as a natural pesticide. In case studies, certain oils have been shown to have a variety of deterring effects on pests, specifically insects and select arthropods.[19] These effects may include repelling, inhibiting digestion, stunting growth,[20] decreasing rate of reproduction, or death of pests that consume the oil. However, the molecules within the oils that cause these effects are normally non-toxic for mammals. These specific actions of the molecules allow for widespread use of these "green" pesticides without harmful effects to anything else other than pests.[21] Essential oils that have been investigated include rose, lemon grass, lavender, thyme, peppermint, basil, cedarwood, and eucalyptus.[22]
Although they may not be the perfect replacement for all synthetic pesticides, essential oils have prospects for crop or indoor plant protection, urban pest control,[23] and marketed insect repellents, such as bug spray. Certain essential oils have been shown in studies to be comparable, if not exceeding, in effectiveness to DEET, which is currently marketed as the most effective mosquito repellent. Although essential oils are effective as pesticides when first applied in uses such as mosquito repellent applied to the skin, it is only effective in the vapor stage. Since this stage is relatively short-lived, creams and polymer mixtures are used in order to elongate the vapor period of effective repellency.[19]
In any form, using essential oils as green pesticides rather than synthetic pesticides has ecological benefits such as decreased residual actions.
Use in food
In relation with their food applications, although these oils have been used throughout history as food preservatives, it was in the 20th century when EOs were considered as Generally Recognized as Safe (GRAS) by the Food and Drug Administration (FDA).[24]
GRAS substances according to the FDA[25]
Common name | Botanical name of plant source |
---|---|
Alfalfa | Medicago sativa L. |
Allspice | Pimenta officinalis Lindl. |
Bitter almond, free from cyanide[26]
|
Prunus amygdalus Batsch, Prunus armeniaca L., or Prunus persica (L.) Batsch. |
Ambrette (seed)
|
Hibiscus moschatus Moench. |
Angelica root | Angelica archangelica L. |
Angelica seed | |
Angelica stem | |
cusparia bark)
|
Galipea officinalis Hancock, Angostura trifoliata |
Anise | Pimpinella anisum L. |
Asafetida
|
Ferula assa-foetida L. and related spp. of Ferula |
Balm (lemon balm) | Melissa officinalis L. |
Balsam of Peru | Myroxylon pereirae Klotzsch. |
Basil | Ocimum basilicum L. |
Bay leaves
|
Laurus nobilis L. |
Bay (myrcia oil) | Pimenta racemosa (Mill.) J. W. Moore. |
Bergamot (bergamot orange) | Citrus aurantium L. subsp. bergamia Wright et Arn. |
Bitter almond (free from prussic acid)
|
Prunus amygdalus Batsch, Prunus armeniaca L., or Prunus persica (L.) Batsch. |
Bois de rose | Aniba rosaeodora Ducke. |
Cacao | Theobroma cacao L. |
Camomile (chamomile) flowers, German or Hungarian | Matricaria chamomilla L. |
Camomile (chamomile) flowers, Roman or English | Anthemis nobilis L. |
Cananga | Cananga odorata Hook. f. and Thoms. |
Capsicum | Capsicum frutescens L. and Capsicum annuum L. |
Caraway | Carum carvi L. |
Cardamom seed (cardamon) | Elettaria cardamomum Maton. |
Carob bean
|
Ceratonia siliqua L. |
Carrot | Daucus carota L. |
Cascarilla bark | Croton eluteria Benn. |
Cassia bark, Chinese | Cinnamomum cassia Blume. |
Cassia bark, Padang or Batavia
|
Cinnamomum burmanni Blume. |
Cassia bark, Saigon | Cinnamomum loureirii Nees. |
Celery seed
|
Apium graveolens L. |
Cherry, wild, bark | Prunus serotina Ehrh. |
Chervil | Anthriscus cerefolium (L.) Hoffm. |
Chicory | Cichorium intybus L. |
Cinnamon bark, Ceylon | Cinnamomum zeylanicum Nees. |
Cinnamon bark, Chinese | Cinnamomum cassia Blume. |
Cinnamon bark, Saigon | Cinnamomum loureirii Nees. |
Cinnamon leaf, Ceylon | Cinnamomum zeylanicum Nees. |
Cinnamon leaf , Chinese
|
Cinnamomum cassia Blume. |
Cinnamon leaf , Saigon
|
Cinnamomum loureirii Nees. |
Citronella | Cymbopogon nardus Rendle. |
Citrus peels | Citrus spp. |
Clary (clary sage)
|
Salvia sclarea L. |
Clover | Trifolium spp. |
Coca (decocainized) | Erythroxylum coca Lam. and other spp. of Erythroxylum |
Coffee | Coffea spp. |
Cola nut | Cola acuminata Schott and Endl., and other spp. of Cola |
Coriander | Coriandrum sativum L. |
Cumin (cummin) | Cuminum cyminum L. |
Curaçao orange peel (orange, bitter peel) | Citrus aurantium L. |
Cusparia bark | Galipea officinalis Hancock |
Dandelion
|
Taraxacum officinale Weber and Taraxacum laevigatum DC. |
Dandelion root | |
Dog grass (quackgrass, triticum) | Agropyron repens (L.) Beauv. |
Elder flowers | Sambucus canadensis L. and Sambucus nigra I. |
Estragole (esdragol, esdragon, tarragon) | Artemisia dracunculus L. |
Estragon (tarragon) | |
Fennel, sweet | Foeniculum vulgare Mill. |
Fenugreek | Trigonella foenum-graecum L. |
Galanga (galangal) | Alpinia officinarum Hance. |
Geranium | Pelargonium spp. |
Geranium, East Indian | Cymbopogon martini Stapf. |
Geranium, rose | Pelargonium graveolens L'Her. |
Ginger | Zingiber officinale Rosc. |
Grapefruit | Citrus paradisi Macf. |
Guava | Psidium spp. |
Hickory bark | Carya spp. |
Horehound (hoarhound) | Marrubium vulgare L. |
Hops | Humulus lupulus L. |
Horsemint | Monarda punctata L. |
Hyssop | Hyssopus officinalis L. |
Immortelle | Helichrysum augustifolium DC. |
Jasmine | Jasminum officinale L. and other spp. of Jasminum |
Juniper (berries) | Juniperus communis L. |
Kola nut | Cola acuminata Schott and Endl., and other spp. of Cola |
Laurel berries | Laurus nobilis L. |
Laurel leaves | Laurus spp. |
Lavender
|
Lavandula officinalis Chaix |
Lavender, spike | Lavandula latifolia Vill. |
Lavandin
|
Hybrids between Lavandula officinalis Chaix and Lavandula latifolin Vill. |
Lemon | Citrus limon (L.) Burm. f. |
Lemon balm (see balm) | Melissa officinalis L. |
Lemongrass | Cymbopogon citratus DC. and Cymbopogon lexuosus Stapf. |
Lemon peel | Citrus limon (L.) Burm. f. |
Lime | Citrus aurantifolia Swingle. |
Linden flowers | Tilia spp. |
Locust bean
|
Ceratonia siliqua L, |
Lupulin
|
Humulus lupulus L. |
Mace
|
Myristica fragrans Houtt. |
Mandarin | Citrus reticulata Blanco. |
Marjoram, sweet | Majorana hortensis Moench. |
Mate, yerba | Ilex paraguariensis St. Hil. |
Melissa (see balm) | |
Menthol | Mentha spp. |
Menthyl acetate | |
Molasses (extract) | Saccharum officinarum L. |
Mustard | Brassica spp. |
Naringin | Citrus paradisi Macf. |
Neroli, bigarade | Citrus aurantium L. |
Nutmeg | Myristica fragrans Houtt. |
Onion | Allium cepa L. |
Orange, bitter, flowers | Citrus aurantium L. |
Orange, bitter, peel | |
Orange leaf | Citrus sinensis (L.) Osbeck. |
Orange, sweet | |
Orange, sweet, flowers | |
Orange, sweet, peel | |
Origanum | Origanum spp. |
Palmarosa | Cymbopogon martini Stapf. |
Paprika | Capsicum annuum L. |
Parsley | Petroselinum crispum (Mill.) Mansf. |
Pepper, black | Piper nigrum L. |
Pepper, white | |
Peppermint | Mentha piperita L. |
Peruvian balsam | Myroxylon pereirae Klotzsch. |
Petitgrain | Citrus aurantium L. |
Petitgrain lemon | Citrus limon (L.) Burm. f. |
Petitgrain mandarin or tangerine | Citrus reticulata Blanco. |
Pimenta | Pimenta officinalis Lindl. |
Pimenta leaf | |
Pipsissewa leaves | Chimaphila umbellata Nutt. |
Pomegranate | Punica granatum L. |
Prickly ash bark | Xanthoxylum (or Zanthoxylum) americanum Mill. or Xanthoxylum clava-herculis L. |
Rose absolute | Rosa alba L., Rosa centifolia L., Rosa damascena Mill., Rosa gallica L., and vars. of these spp. |
Rose (otto of roses, attar of roses) | |
Rose buds | |
Rose flowers | |
Rose fruit (hips) | |
Rose geranium | Pelargonium graveolens L'Her. |
Rose leaves | Rosa spp. |
Rosemary | Rosmarinus officinalis L. |
Saffron | Crocus sativus L. |
Sage
|
Salvia officinalis L. |
Sage , Greek
|
Salvia triloba L. |
Sage, Spanish | Salvia lavandulaefolia Vahl. |
St. John's bread | Ceratonia siliqua L. |
Savory, summer | Satureia hortensis L. |
Savory, winter | Satureia montana L. |
Schinus molle | Schinus molle L. |
Sloe berries (blackthorn berries) | Prunus spinosa L. |
Spearmint | Mentha spicata L. |
Spike lavender
|
Lavandula latifolia Vill. |
Tamarind | Tamarindus indica L. |
Tangerine | Citrus reticulata Blanco. |
Tarragon | Artemisia dracunculus L. |
Tea | Thea sinensis L. |
Thyme | Thymus vulgaris L. and Thymus zygis var. gracilis Boiss. |
Thyme, white | |
Thyme, wild or creeping | Thymus serpyllum L. |
Triticum (see dog grass) | Elymus repens |
Tuberose | Polianthes tuberosa L. |
Turmeric | Curcuma longa L. |
Vanilla | Vanilla planifolia Andr. or Vanilla tahitensis J. W. Moore. |
Violet flowers | Viola odorata L. |
Violet leaves | |
Violet leaves absolute | |
Wild cherry bark | Prunus serotina Ehrh. |
Ylang-ylang | Cananga odorata Hook. f. and Thoms. |
Zedoary bark | Curcuma zedoaria Rosc. |
As antimicrobials
The most commonly used essential oils with antimicrobial action are:
Some essential oils are effective
Dilution
Essential oils are usually
Raw materials
Essential oils are derived from sections of plants. Some plants, like the bitter orange, are sources of several types of essential oil.
- Benzoin
- Copaiba
- Frankincense
- Labdanum
- Myrrh
- Anise
- Buchu
- Celery
- Cumin
- Flax
- Nutmeg oil
Balsam of Peru
Balsam of Peru, an essential oil derived from Myroxylon plants, is used in food and drink for flavoring, in perfumes and toiletries for fragrance, and in animal care products.[28] However, national and international surveys identified balsam of Peru among the "top five" allergens most commonly causing patch test allergic reactions in people referred to dermatology clinics.[29][30][31]
Garlic oil
Garlic oil is an essential oil derived from garlic.[32]
Eucalyptus oil
Most eucalyptus oil on the market is produced from the leaves of Eucalyptus globulus. Steam-distilled eucalyptus oil is used throughout Asia, Africa, Latin America and South America as a primary cleaning/disinfecting agent added to soaped mop and countertop cleaning solutions; it also possesses insect and limited vermin control properties.[33] Note, however, there are hundreds of species of eucalyptus, and perhaps some dozens are used to various extents as sources of essential oils. Not only do the products of different species differ greatly in characteristics and effects, but also the products of the very same tree can vary grossly.[34]
Lavender oil
Lavender oil has long been used in the production of perfume.[35] However, studies have shown it can be estrogenic and antiandrogenic, causing problems for prepubescent boys and pregnant women, in particular.[36] Lavender essential oil is also used as an insect repellent.[37]
Rose oil
Toxicity
The potential toxicity of essential oil is related to its level or grade of purity, and to the toxicity of specific chemical components of the oil.[5] Many essential oils are designed exclusively for their aroma-therapeutic quality; these essential oils generally should not be applied directly to the skin in their undiluted form.[5] Some can cause severe irritation, provoke an allergic reaction and, over time, prove toxic to the liver. If ingested or rubbed into the skin, essential oils can be highly poisonous, causing confusion, choking, loss of muscle coordination, difficulty in breathing, pneumonia, seizures, and possibly severe allergic reactions or coma.[5]
Some essential oils, including many of the
Industrial users of essential oils should consult the safety data sheets to determine the hazards and handling requirements of particular oils.[5] Even certain therapeutic-grade oils can pose potential threats to individuals with epilepsy or pregnant women.
Essential oil use in children can pose a danger when misused because of their thin skin and immature livers. This might cause them to be more susceptible to toxic effects than adults.[5]
Flammability
The
Gynecomastia
Handling
Exposure to essential oils may cause contact dermatitis.[13][14][15] Essential oils can be aggressive toward rubbers and plastics, so care must be taken in choosing the correct handling equipment. Glass syringes are often used, but have coarse volumetric graduations. Chemistry syringes are ideal, as they resist essential oils, are long enough to enter deep vessels, and have fine graduations, facilitating quality control. Unlike traditional pipettes, which have difficulty handling viscous fluids, the chemistry syringe, also known as a positive displacement pipette, has a seal and piston arrangement which slides inside the pipette, wiping the essential oil off the pipette wall.
Ingestion
Some essential oils qualify as
Pesticide residues
Concern about pesticide residues in essential oils, particularly those used therapeutically, means many practitioners of aromatherapy buy organically produced oils. Not only are pesticides present in trace quantities, but also the oils themselves are used in tiny quantities and usually in high dilutions. Where there is a concern about pesticide residues in food essential oils, such as mint or orange oils, the proper criterion is not solely whether the material is organically produced, but whether it meets the government standards based on actual analysis of its pesticide content.[44]
Pregnancy
Some essential oils may contain impurities and additives that may be harmful to pregnant women.[45] Certain essential oils are safe to use during pregnancy, but care must be taken when selecting quality and brand. Sensitivity to certain smells may cause pregnant women to have adverse side effects with essential oil use, such as headache, vertigo, and nausea. Pregnant women often report an abnormal sensitivity to smells and taste,[46] and essential oils can cause irritation and nausea when ingested.[5]
Toxicology
The following table lists the LD50 or median lethal dose for common oils; this is the dose required to kill half the members of a tested animal population. LD50 is intended as a guideline only, and reported values can vary widely due to differences in tested species and testing conditions.[47]
Common Name | Oral LD50 | Dermal LD50 | Notes |
---|---|---|---|
Neem | 14 g/kg | >2 g/kg | |
Lemon myrtle | 2.43 g/kg | 2.25 g/kg | |
Frankincense | >5 g/kg | >5 g/kg | Boswellia carterii |
Frankincense | >2 g/kg | >2 g/kg | Boswellia sacra |
Indian frankincense | >2 g/kg | >2 g/kg | Boswellia serrata |
Ylang-ylang | >5 g/kg | >5 g/kg | |
Cedarwood | >5 g/kg | >5 g/kg | |
Roman chamomile | >5 g/kg | >5 g/kg | |
White camphor | >5 g/kg | >5 g/kg | Cinnamomum camphora, extracted from leaves |
Yellow camphor | 3.73 g/kg | >5 g/kg | Cinnamomum camphora, extracted from bark |
Hot oil | 3.80 g/kg | >5 g/kg | Cinnamomum camphora, oil extracted from leaves |
Cassia | 2.80 g/kg | 0.32 g/kg |
Standardization of derived products
In 2002, ISO published ISO 4720 in which the botanical names of the relevant plants are standardized.[48] The rest of the standards with regards to this topic can be found in the section of ICS 71.100.60 [49]
History
This section needs additional citations for verification. (November 2021) |
The resins of aromatics and plant extracts were retained to produce traditional medicines and scented preparations, such as perfumes and incense, including frankincense, myrrh, cedarwood, juniper berry and cinnamon in ancient Egypt may have contained essential oils.[50][51] In 1923, when archaeologists opened Pharaoh Tutankhamun’s tomb, they found 50 alabaster jars of essential oils.[51][dubious ]
Essential oils have been used in
Rather than refer to essential oils themselves, modern works typically discuss specific chemical compounds of which the essential oils are composed, such as referring to methyl salicylate rather than "oil of wintergreen".[54][55]
Essential oils are used in aromatherapy, a branch of alternative medicine that uses essential oils and other aromatic compounds.[56] Oils are volatilized, diluted in a carrier oil and used in massage, diffused in the air by a nebulizer or diffuser, heated over a candle flame, or burned as incense.
See also
References
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- ^ a b c d e f g h "Essential oils: Poisonous when misused". US National Capital Poison Center. Retrieved 2017-12-01.
- ^ Shutes J. "How Are Essential Oils Extracted?". NAHA – National Association for Holistic Aromatherapy. Archived from the original on 11 June 2013. Retrieved 16 June 2019.
- ISBN 978-0-85207-215-8.
- PMID 25471637.
- ^ "ISO TC 54 Business Plan – Essential oils" (PDF). Retrieved 2006-09-14. It is unclear from the source what period of time the quoted figures include.
- ^ a b Sapeika N (1963). Actions and Uses of Drugs. A.A. Balkema.[page needed]
- ^ Haneke KE (February 2002), Turpentine (Turpentine Oil, Wood Turpentine, Sulfate Turpentine, Sulfite Turpentine) [8006-64-2]: Review of Toxicological Literature (PDF), National Institute of Environmental Health Sciences[page needed]
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- Lay summary in: "Essential oil poisoning calls on the rise, children most affected". University of Sydney. December 9, 2019.
- ^ "Aromatherapy: The Best Essential Oil Diffuser". simplerandsmarter.com.au. Retrieved 2016-05-15.
- ^ Schiffer J (March 11, 2021). "Essential Oils May Be Wreaking Havoc on Your Skin". The New York Times.
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- ^ a b "CFR - Code of Federal Regulations Title 21". www.accessdata.fda.gov. Retrieved 2018-12-08. This article incorporates text from this source, which is in the public domain.
- ^ "Wieviel Prozent Blausäure enthält natürliches Bittermandelöl?".
- ^ S2CID 58656780.
- ^ "Balsam of Peru". go.drugbank.com. DrugBank. 11 December 2021. Retrieved 2021-12-15.
- ISBN 978-3-540-77782-3. Archivedfrom the original on May 18, 2016. Retrieved March 5, 2014.
- ISBN 978-0-323-08037-8. Retrieved March 6, 2014.
- ISBN 978-0-323-22572-4.
- ISBN 978-3-642-84023-4. Retrieved December 29, 2017.
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- ^ Thorpe's Dictionary of Applied Chemistry. Vol. 8 (4th ed.). Longmans Green. 1947.[page needed]
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- Directorate-General for Health and Consumers: European Commission: European Union
- ^ "More evidence essential oils 'make male breasts develop'". BBC News. BBC. 18 March 2018. Retrieved 18 March 2018.
A suspected link between abnormal breast growth in young boys and the use of lavender and tea tree oils has been given new weight, after a study found eight chemicals contained in the oils interfere with hormones.
- PMID 9576358.
- ISBN 978-1-74151-709-5.[page needed]
- ISSN 2053-6178.
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- ^ Dweck AC (September 2009). "Toxicology of essential oils reviewed" (PDF). Personal Care. Archived from the original (PDF) on 2011-07-18. Retrieved 2011-01-05.
- ^ International Organization for Standardization. "ISO 4720:2002 Essential oils – Nomenclature". Retrieved April 23, 2009.
- ^ International Organization for Standardization. "71.100.60: Essential oils". Retrieved June 14, 2009.
- ISBN 978-1-4200-6316-5.
- ^ ISBN 978-0-7684-1188-1.
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- ISBN 978-0-07-105239-9.[page needed]
- ^ "Aromatherapy: Uses, benefits, oils, and risks". www.medicalnewstoday.com. 2017-03-20. Retrieved 2022-02-16.
Further reading
- Baser, K.H.C., G. Buchbauer (2010). Handbook of Essential Oils: Science, Technology and Applications. CRC Press, Boca Raton, London, New York. ISBN 978-1-4200-6315-8.
- Schnaubelt, Kurt (1999). Advanced Aromatherapy: The Science of Essential Oil Therapy. Healing Arts Press. ISBN 978-0-89281-743-6.
- Sellar, Wanda (2001). The Directory of Essential Oils (Reprint ed.). Essex: The C.W. Daniel Company, Ltd. ISBN 978-0-85207-346-9.
- Tisserand, Robert (1995). Essential Oil Safety: A Guide for Health Care Professionals. Churchill Livingstone. ISBN 978-0-443-05260-6.
- Rimal V, Shishodia S, Srivastava PK, Gupta S, Mallick AI (2021). "Synthesis and characterization of Indian essential oil Carbon Dots for interdisciplinary applications". Applied Nanoscience. 11 (4): 1225–1239. S2CID 232145772.