An essential oil is a concentrated hydrophobic liquid containing volatile (easily evaporated at normal temperatures) chemical compounds from . Essential oils are also known as volatile oils, ethereal oils, aetheroleum, or simply as the oil of the plant from which they were extracted, such as oil of clove. An essential oil is essential in the sense that it contains the essence of the plant's fragrance—the characteristic fragrance of the plant from which it is derived. The term "essential" used here does not mean required or usable by the human body, as with the terms essential amino acid or essential fatty acid, which are so called because they are nutritionally required by a living organism.
Essential oils are generally extracted by distillation, often by using steam. Other processes include expression, solvent extraction, sfumatura, absolute oil extraction, resin tapping, wax embedding, and cold pressing. They are used in perfumes, cosmetics, , Air freshener and other products, for flavoring food and drink, and for adding scents to incense and household cleaning products.
Essential oils are often used for aromatherapy, a form of alternative medicine in which healing effects are ascribed to aromatic compounds. There is not sufficient evidence that it can effectively treat any condition. 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. Essential oils can be poisonous if ingested or absorbed through the skin.
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, herbal distillate, or plant water essence, which may be sold as another fragrant product. Hydrosols include rose water, lavender water, lemon balm, clary sage, and orange blossom water.
Before the discovery of distillation, all essential oils were extracted by pressing.
Although highly fragrant, concretes contain large quantities of non-fragrant waxes and resins. Often, another solvent, such as ethanol, is used to extract the fragrant oil from the concrete. The alcohol solution is chilled to for more than 48 hours which causes the and to precipitate out. The precipitates are then filtered out and the ethanol is removed from the remaining solution by evaporation, vacuum purge, or both, leaving behind the absolute.
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.
! Oil !! Tonnes |
12,000 |
4,800 |
3,200 |
2,600 |
2,300 |
2,070 |
2,000 |
2,000 |
1,300 |
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.
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, 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.
In any form, using essential oils as green pesticides rather than synthetic pesticides has ecological benefits such as decreased residual actions. In addition, increased use of essential oils as pest control could have not only ecological, but economical benefits as the essential oil market diversifies and popularity increases among organic farmers and environmentally conscious consumers. some EOs are authorized, and in use, in the European Union: Melaleuca oil as a fungicide, citronella oil as a herbicide, Syzygium aromaticum oil as a fungicide and bactericide, Mentha spicata oil as a plant growth regulator; Citrus sinensis oil (only in France) for Bemisia tabaci on Cucurbita pepo and Trialeurodes vaporariorum on Solanum lycopersicum; and approvals for oils of Thymus, C. sinensis, and Tagetes as insecticides are pending.
GRAS substances according to the FDA
Alfalfa | Medicago sativa L. |
Allspice | Pimenta officinalis Lindl. |
Bitter almond, free from cyanide | 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 | |
Angostura (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. |
Pimenta racemosa | Pimenta racemosa (Mill.) J. W. Moore. |
Bergamot orange (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. |
Rosewood oil | Aniba rosaeodora Ducke. |
Theobroma cacao | Theobroma cacao L. |
Camomile (chamomile) flowers, German or Hungarian | Matricaria chamomilla L. |
Camomile (chamomile) flowers, Roman or English | Anthemis nobilis L. |
Cananga odorata | Cananga odorata Hook. f. and Thoms. |
Capsicum | Capsicum frutescens L. and Capsicum annuum L. |
Caraway | Carum carvi L. |
Cardamom (cardamon) | Elettaria cardamomum Maton. |
Carob bean | Ceratonia siliqua L. |
Carrot | Daucus carota L. |
Croton eluteria | Croton eluteria Benn. |
Cassia bark, Chinese | Cinnamomum cassia Blume. |
Cassia bark, Padang or Batavia | Cinnamomum burmanni Blume. |
Saigon cinnamon | Cinnamomum loureirii Nees. |
Celery seed | Apium graveolens L. |
Prunus serotina, bark | Prunus serotina Ehrh. |
Chervil | Anthriscus cerefolium (L.) Hoffm. |
Chicory | Cichorium intybus L. |
Cinnamomum verum | Cinnamomum zeylanicum Nees. |
Cinnamon bark, Chinese | Cinnamomum cassia Blume. |
Saigon cinnamon | Cinnamomum loureirii Nees. |
Cinnamomum verum | Cinnamomum zeylanicum Nees. |
Cinnamon leaf, Chinese | Cinnamomum cassia Blume. |
Cinnamon leaf, Saigon | Cinnamomum loureirii Nees. |
Citronella oil | Cymbopogon nardus Rendle. |
Citrus | Citrus spp. |
Clary Sage (clary sage) | Salvia sclarea L. |
Clover | Trifolium spp. |
Coca (decocainized) | Erythroxylum coca Lam. and other spp. of Erythroxylum |
Coffea | Coffea spp. |
Kola nut | Cola acuminata Schott and Endl., and other spp. of Cola |
Coriander | Coriandrum sativum L. |
Cumin (cummin) | Cuminum cyminum L. |
Bitter orange (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. |
Estragole | |
Fennel, sweet | Foeniculum vulgare Mill. |
Fenugreek | Trigonella foenum-graecum L. |
Galangal (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. |
Helichrysum | 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. |
Cymbopogon | Cymbopogon citratus DC. and Cymbopogon lexuosus Stapf. |
Lemon peel | Citrus limon (L.) Burm. f. |
Lime | Citrus aurantifolia Swingle. |
Tilia cordata 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. |
Yerba mate | 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 | 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. |
Black pepper | 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. |
Allspice | Pimenta officinalis Lindl. |
Pimenta leaf | |
Pipsissewa leaves | Chimaphila umbellata Nutt. |
Pomegranate | Punica granatum L. |
Zanthoxylum | 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. |
Salvia triloba, Greek | Salvia triloba L. |
Sage, Spanish | Salvia officinalis subsp. lavandulifolia (Vahl) Gams |
Carob | Ceratonia siliqua L. |
Summer savory | Satureia hortensis L. |
Winter savory, winter | Satureia montana L. |
Schinus molle | Schinus molle L. |
Prunus spinosa (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. |
Thymelaeaceae | Thymus vulgaris L. and Thymus zygis var. gracilis Boiss. |
Thyme, white | |
Thymus serpyllum, wild or creeping | Thymus serpyllum L. |
Elymus repens (see dog grass) | Elymus repens |
Agave amica | Polianthes tuberosa L. |
Turmeric | Curcuma longa L. |
Vanilla | Vanilla planifolia Andr. or Vanilla tahitensis J. W. Moore. |
Violet flowers | Viola odorata L. |
Viola odorata | |
Viola odorata | |
Prunus serotina | Prunus serotina Ehrh. |
Cananga odorata | Cananga odorata Hook. f. and Thoms. |
Curcuma zedoaria | Curcuma zedoaria Rosc. |
Some essential oils are effective antimicrobials and have been evaluated for food incorporation in vitro. However, actual deployment is rare because much higher concentrations are required in real foods. Some or all of this lower effectiveness is due to large differences between culture medium and foods in chemistry (especially lipid content), viscosity, and duration of inoculation/storage.
| valign="top" |
|
|
|
Some essential oils, including many of the citrus peel oils, are , increasing vulnerability of the skin to sunlight.
Industrial users of essential oils should consult the safety data sheets to determine the hazards and handling requirements of particular oils. 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.
Boswellia carterii |
Boswellia sacra |
Boswellia serrata |
Cinnamomum camphora, extracted from leaves |
Cinnamomum camphora, extracted from bark |
Cinnamomum camphora, oil extracted from leaves |
Essential oils have been used in folk medicine over centuries. The Persian physician Avicenna, known as Avicenna in Europe, was first to derive the fragrance of flowers from distillation,
while the earliest recorded mention of the techniques and methods used to produce essential oils may be Ibn al-Baitar (1188–1248), an Arab (Muslim Spain) physician, pharmacist and chemist.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".
Essential oils are used in aromatherapy, a branch of alternative medicine that uses essential oils and other aromatic compounds. 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.
|
|