Essential Oil

ESSENTIAL OIL

An essential oil is a concentrated, hydrophobic liquid containing volatile
aroma compounds from plants. Essential oils are also known as volatile
or ethereal oils, or simply as the "oil of" the plant from which they were
extracted, such as oil of clove. An oil is "essential" in the sense that it
carries a distinctive scent, or essence, of the plant. Essential oils do not
as a group need to have any specific chemical properties in common,
beyond conveying characteristic fragrances.
Essential oils are generally extracted by distillation. Other processes
include expression, or solvent extraction. They are used in perfumes,
cosmetics, soap and other products, for flavoring food and drink, and for
scenting incense and household cleaning products.
Various essential oils have been used medicinally at different periods in
history. Medical application proposed by those who sell medicinal oils
range from skin treatments to remedies for cancer, and are often based
on historical use of these oils for these purposes. Such claims are now
subject to regulation in most countries, and have grown more vague to
stay within these regulations.
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, diffused in the
air by a nebulizer or by heating over a candle flame, or burned as
incense, for example.
Distillation
Today, most common essential oils, such as lavender, peppermint, 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 takes 22 hours to complete 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. Popular hydrosols include 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 smells
and are therefore not sold.
Expression
Most citrus peel oils are expressed mechanically, or cold-pressed. Due
to the relatively large quantities of oil in citrus peel and 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-
products of the citrus industry are even cheaper.
Prior to the discovery of distillation, all essential oils were extracted by
pressing.
Solvent extraction
Most flowers contain too 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 concretes, which is a
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 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.
Supercritical carbon dioxide is used as a solvent in supercritical fluid
extraction. This method has many benefits, including avoiding
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 back to a gas, leaving no residue. An animated presentation
describing the process is available for viewing.
Supercritical carbon dioxide is also used for making decaffeinated
coffee. However, although it uses the same basic principles it is a
different process because of the difference in scale.


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.
[1]

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

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. 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.
[2]
Many are also claimed to have an uplifting effect on the
mind. The claims are supported in some studies
[3][4]
and unconfirmed in
others.
[5]

Dilution
Essential oils are usually lipophilic (literally: "oil-loving") compounds
that usually are not miscible with water. Instead, they can be diluted in
solvents like pure ethanol (alcohol), polyethylene glycol, or oils.



Raw materials
Essential oils are derived from various sections of plants. Some plants,
like the bitter orange, are sources of several types of essential oil.
Berries
 Allspice
 Juniper
Seeds
 Almond
 Anise
 Celery
 Cumin
 Nutmeg oil
Bark
 Cassia
 Cinnamon
 Sassafras
Wood
Leaves
 Basil
 Bay leaf
 Cinnamon
 Common sage
 Eucalyptus
 Lemon grass
 Melaleuca
 Oregano
 Patchouli
 Peppermint
 Pine
 Rosemary
 Spearmint
 Tea tree
 Thyme
Flowers
 Cannabis
 Chamomile
 Clary sage
 Clove
 Scented
geranium
 Hops
 Hyssop
 Jasmine
 Lavender
 Manuka
 Marjoram
 Orange
 Rose
 Ylang-ylang
 Camphor
 Cedar
 Rosewood
 Sandalwood
 Agarwood
Rhizome
 Galangal
 Ginger
 Wintergreen
Resin
 Frankincense
 Myrrh
Peel
 Bergamot
 Grapefruit
 Lemon
 Lime
 Orange
 Tangerine
Root
 Valerian








Rose oil
The most well-known essential oil is probably rose oil, produced from
the petals of Rosa damascena and Rosa centifolia. Steam-distilled rose
oil is known as "rose otto" while the solvent extracted product is known
as "rose absolute".
Dangers
Because of their concentrated nature, essential oils generally should not
be applied directly to the skin in their undiluted or "neat" form. Some
can cause severe irritation or provoke an allergic reaction. Instead,
essential oils should be blended with a vegetable-based "carrier" oil
(a.k.a., a base, or "fixed" oil) before being applied. Common carrier oils
include olive, almond, hazelnut and grapeseed. Only neutral oils should
be used. A common ratio of essential oil disbursed in a carrier oil is 0.5–
3% (most under 10%), depending on its purpose. Some essential oils,
including many of the citrus peel oils, are photosensitizers, increasing
the skin's vulnerability to sunlight. Industrial users of essential oils
should consult the material safety data sheets (MSDS) to determine the
hazards and handling requirements of particular oils.


Gynecomastia
Estrogenic and antiandrogenic activity have been reported by in vitro
study of tea tree oil and lavender essential oils. Case reports suggest that
the oils may be implicated in some cases of gynecomastia, an abnormal
breast tissue growth, in prepubescent boys.
[6][7]

Pesticide residues
There is some concern about pesticide residues in essential oils,
particularly those used therapeutically. For this reason, many
practitioners of aromatherapy buy organically produced oils.
Ingestion
While some advocate the ingestion of essential oils for therapeutic
purposes, this should never be done except under the supervision of
someone licensed to prescribe such treatment. Some common essential
oils such as Eucalyptus are toxic internally. Pharmacopoeia standards for
medicinal oils should be heeded. Some oils can be toxic to some
domestic animals, cats in particular.
[8]
The internal use of essential oils
can pose hazards to pregnant women, as some can be abortifacients in
dose 0.5–10 ml.


Flammability
The flash point of each essential oil is different. Many of the common
essential oils such as tea tree, lavender, and citrus oils are classed as a
Class 3 Flammable Liquid as they have a flash point of 50–60 °C.
Toxicology
LD
50
of most essential oils or their main components are 0.5–10 mg/kg
(orally or skin test). This compares with, for example, the LD
50
of
arsenic acid, one of the most common arsenic based poisons which is
6 mg/kg (rabbits).
[9]

Standardization of its derived products
In 2002, ISO published ISO 4720 in which the botanical names of the
relevant plants are standardized
[10]
. The rest of the standards with
regards to this topic can be found in the section of ICS 71.100.60
[11]

Fragrance oil
Fragrance oil(s), also known as aroma oils, aromatic oils, and flavor
oils, are blended synthetic aroma compounds or natural essential oils
that are diluted with a carrier like propylene glycol, vegetable oil, or
mineral oil. Aromatic oils are used in perfumery, cosmetics, flavoring of
food, and in aromatherapy.

LIST OF ESSENTIAL OILS

Essential oils are volatile and liquid aroma compounds from natural
sources, usually plants. Essential oils are not oils in a strict sense, but
often share with oils a poor solubility in water. Essential oils often have
an odor and are therefore used in food flavoring and perfumery.
Essential oils are usually prepared by fragrance extraction techniques
such as distillation (including steam distillation), cold pressing, or
extraction (maceration). Essential oils are distinguished from aroma oils
(essential oils and aroma compounds in an oily solvent), infusions in a
vegetable oil, absolutes, and concretes. Typically, essential oils are
highly complex mixtures of often hundreds of individual aroma
compounds.
 Agar oil, distilled from Agarwood (Aquilaria malaccensis). Highly
prized for its fragrance.
[1]

 Ajwain oil, distilled from the leaves of Bishop’s weed (Carum
copticum). Oil contains 35-65% thymol.
[2]

 Angelica root oil, distilled from the Angelica archangelica.
[3]

 Anise oil, from the Pimpinella anisum, rich odor of licorice, used
medicinally.
[4]

 Asafoetida, used medicinally and to flavor food.
 Balsam oil, from the Myroxylon pereirae.
[5]

 Basil oil is used in making perfumes, as well as in aromatherapy
 Bay is used in perfumery; Aromatherapeutic for sprains, colds, flu,
insomnia, rheumatism.
 Bergamot oil, used in aromatherapy and in perfumes.
 Black Pepper essential oil is distilled from the berries of Piper
nigrum. The warm,soothing effect makes it ideal for treating
muscle aches, pains and strains.
 Buchu oil, made from the buchu shrub. Considered toxic and no
longer widely used. Formerly used medicinally.
 Birch is aromatheapeutic for gout, Rheumatism, Eczema, Ulcers.
 Camphor is used for cold, cough, fever, rheumatism, arthritis
 Cannabis flower essential oil, used as a flavoring in foods,
primarily candy and beverages. Also used as a scent in perfumes,
cosmetics, soaps, and candles.
[6]

 Caraway oil, used a flavoring in foods. Also used in mouthwashes,
toothpastes, etc. as a flavoring agent.
[7]

 Cardamom seed oil, used in aromatherapy and other medicinal
applications. Extracted from seeds of subspecies of Zingiberaceae
(ginger). Also used as a fragrance in soaps, perfumes, etc.
[8]

 Carrot seed oil (essential oil), used in aromatherapy.
 Cedarwood oil, primarily used in perfumes and fragrances.
[9]

 Chamomile oil, There are many varieties of chamomile but only
two are used in aromatherapy- Roman and German. Both have
similar healing properties but German chamomile contains a higher
level of azulin (an anti-inflammatory agent).
 Calamus Root, used medicinally
 Cinnamon oil, used for flavoring and medicinally.
 Cistus species
 Citronella oil, from a plant related to lemon grass is used as an
insect repellent, as well as medicinally.
 Clary Sage
 Clove leaf oil, used as a topical anesthetic to relieve dental pain.
 Coffee, used to flavor food.
 Coriander
 Costmary oil (bible leaf oil), from the Tanacetum balsamita
[10][11]

 Costus Root, used medicinally
 Cranberry seed oil, equally high in omega-3 omega-6 fatty acids,
primarily used in the cosmetic industry.
 Cubeb, used medicinally and to flavor foods.
 Cumin oil/Black seed oil, used as a flavor, particularly in meat
products. Also used in veterinary medicine.
 Cypress
 Cypriol
 Curry leaf, used medicinally and to flavor food.
 Davana oil, from the Artemisia pallens, used as a perfume
ingredient and as a germicide.
[12]

 Dill oil, chemically almost identical to caraway seed oil. High
carvone content.
 Elecampane, used medicinally.
 Eucalyptus oil, historically used as a germicide. Commonly used in
cough medicine, among other medicinal uses.
[13]

 Fennel seed oil, used medicinally, particularly for treating colic in
infants.
 Fenugreek oil, used medicinally and for cosmetics from ancient
times.
 Fir
 Frankincense oil, used for aromatherapy and in perfumes.
 Galangal, used medicinally and to flavor food.
 Galbanum
 Geranium oil, used medicinally, particularly in aromatherapy, used
for hormonal imbalance, for this reason geranium is often
considered to be "female" oil.
 Ginger oil, used medicinally in many cultures.
 Goldenrod
 Grapefruit oil, extracted from the peel of the fruit. Used in
aromatherapy. Contains 90% limonene.
[14]

 Henna oil, used medicinally.
[15]

 Helichrysum
 Horseradish oil
 Hyssop
 Idaho Tansy
 Jasmine oil, used for its flowery fragrance.