Volatile oils (continued’) Pharmacognosy I Mosul University/ college of Pharmacy L.A. Dilbreen Barzanji

Turpentine oil Pharmaceutical turpentine oil obtained by distillation and rectification from the oleoresin produced by various species of Pinus. The unrectified oil is the turpentine of commerce. Rectification of the commercial oil consists of the treatment with aqueous alkali to remove traces of phenols, cresols, resin acids, etc. and possible redistillation. The genus Pinus is widely distributed and many countries have considerable reserve of pine forest. Oil of turpentine is a colourless liquid with a characteristic odour and a pungent taste. It is soluble in alcohol, ether, chloroform and glacial acetic acid

Oil of turpentine consists cheifly of terpenes (+)- and (-)-α-pinene, (-)-β-pinene and camphene. These tend to undergo atmospheric oxidation with the formation of complex resinous substances, the removal of which is accomplished by the process of rectification. Use: Externally; it is used as a counterirritant and rubefacient. For inhalation; terebene is usually preferred (terebene is prepared from oil turpentine by action of cold sulpheric acid, which converts the pinene into limonene) Now , most turpentine is processed to give its variuos constituents which find use in the manufacture of fragrance, flavours, vitamines, insecticides, etc.

Lemon oils Lemon oil is obtained by suitable mechanical means, without the aid of heat, from the fresh peel of Citrus limon. Once the oil has been separated from the peel, it can be distilled without deterioration in quality, and some expressed oil of lemon is fractionally distilled to make terpenless oil of lemon (terpenless lemon oil is equivalent to about 10-15 times its volume of lemon oil). Distillation direct from the peel is quiet different, and, although much oil is prepared from the peel by steam distillation, this is inferior and doesn’t comply with the definition given above. Distilled oil of lemon is cheaper than that prepared by expression and large quantities of it are made and used for non-pharmaceutical purposes.

Lemon oil contains terpenes (about 94% mainly (+)-limonene), sesquiterpenes, aldehydes (citral and citronellal) and esters (genaryl actate). Lemon oil shows a marked tendency to resinify and should be protected from the action of air and light as much as possible. Principal reactions may cause: oxidations of monoterpenes, aldehydes and esters Peroxide formation Polymerization and isomerization (e.g. lemonine → α-terpinene).

Oil of lemon is used for flavouring and in perfumery. Lemon spirit BP is a 10% solution in ethanol (96%) and it is also an ingredient of Compound Orange Spirit BP.

Bitter orange peel and sweet orange peel Bitter orange peel is the dried outer part of the pericarp of the ripe or nearly ripe fruit known as the bitter, Seville or Bigarade orange. In botanical characteristic the tree is not like the sweet orange and both regarded subspecies or varieties of Citrus aurantium. The peel of the sweet orange is thinner than that of the bitter, more yellowish in colour and less rough, and the taste, though pungent and aromatic, lacks the extreme bitterness of the Seville peel.

Orange oils The volatile oil of the orange may be extracted by methods other than distillation (see ‘lemon oil’). That from the bitter orange peel is known as Essence de Bigarde and that of the sweet orange is called Essence de Portugal. Sweet orange oil is obtained by mechanical expression of the fresh peel; although chemically almost identical with bitter orange oil, it does not have the bitter taste or odour of the later. These oils contain the terpene (+)-limonene and smaller quantities of citral, citronellal, methyl anthranilate. Uses: flavouring agent in elixirs and other preparations.

Bitter orange flower oil This oil, also known as Oil of Niroli, is prepared by steam distillation from the fresh flowers of the bitter orange. An alcoholic solution of the oil has a violet-blue fluorescence arising from the small content (0.1-1.0%) of methyl anthranilate which is also responsible for the characteristic odour of the oil. In Britain the oil was traditionally used for the making of concentrated orange-flower water, syrup of orange flowers and Cologne spirit. It is used in aromatherapy.

Tea-tree oil The clear colourless to pale-yellow oil is obtained by distillation from the leaves and terminal branches of Melaleuca alternifolia. Cyclic monoterpenes constitute the principal components of the oil: terpinen-4-ol, cineole, p-cymene and α-terpinene. In recent years the popularity of tea- tree preparations has increased enormously to include antiseptic creams for skin treatment, inhalations and pastilles for throat infections.

Chamolmile flowers (Roman chamomile) Chamomile flowers are the expanded flower-heads of Chamomile nobile (Anthimes nobilis) (f. Compositae). The flowers are collected in dry weather and carefully dried. The crop is often damaged by wet weather and discoloured flowers then often obtained fetch a much lower price than those having good colour. Chamonile contains 0.4-1.0% of volatile oil which is blue when freshly distilled owing to the presence of azulene. Other components of the oil are n-butyl angelate (principal), iso-amyl angelate, tridecanal, pentadecanal and terpenes.

For the production of volatile oil, the entire aerial parts are usually used. Uses: considerable quantities of chamomile are used in domestic medicine in the form of an infusion (for dyspepsia, colic , etc). Chamomile oil are also used as massage oil, and in cosmetics, shampoos, and to alleviate skin conditions.

Matricaria flowers (german or hungarian chamomile) The dried flower-heads of Matricaria recutita.(Compositae) The flower-heads are required to contain not less than 0.4% of a blue volatile oil; this consist mainly of the sesquiterpenes α-bisabolol, chamazulene and farnesene. Chamazulene itself doesn’t occur in the plant but is formed from a sesquiterpenes lactone (matricin) during steam distillation. Uses: Matricaria flowers are mainly used in the continent of Europe and in the USA for their anti-inflammatory and spasmolytic properties. The ulcer protective properties of German chamomile have been ascribed to bisabolol type constituents, on which considerable pharmacological work have been reported.

Other volatile oils used in medicinal and pharmaceutical purposes Rosemary oil : used in aromatherapy, in the perfumery industry and for the preparation of spirits and liniments for medicinal use; it has antibacterial and antispasmodic properties. Lavender oil: lavender oil is sedative and used to alleviate restlessness and insomnia. lavender flower are indicated for the treatment of flatulence dyspepsia and topically, as the oil, for rheumatic pain. Aniseed oil and star anise oil are used as flavouring agents and as carminatives. Fennel and its volatile oil are used as an aromatic and carminative.

Cinnamon oil: is used as flavouring agent and mild astringent Cinnamon oil: is used as flavouring agent and mild astringent. The oil has carminative properties and is a powerful germicide. Clove oil: The most important and common use is in dental care. It is also used as flavouring agent, stimulant, aromatic and antiseptic. Cardamom oil: the principal use is flavouring agent. Some is used in the manufacture of liqueurs and a relative small amounts in pharmacy, chiefly in the form of Compound tincture of Cardamom. Ginger oil: is used as carminative and stimulant. It may ameliorate the effects of motion sickness. Ginger is also effective in the control of excessive and uncontrolled vomiting occurring in the first trimester of pregnancy and that it may provide a cheap antiemetic adjunct to cancer therapy.

Volatile oils in aromatherapy Aromatherapy is based primarily on the use of volatile oils, either singly or in admixture. They are administered in baths (drops of oil are added to the water and vigorously mixed), in compresses, in massage and as inhalations. For compresses and massage usage the volatile oils are mixed with a suitable carrier (e.g. the fixed oils of apricot kernel, evening primerose, starflower, sweet almond), and for inhalation vaporizers and burners are available in addition to the traditional steam inhalation or use of the handkerchief or tissue.

A number of the oils used in the aromatherapy have been already mentioned and include those from chamomile, cinnamon leaf, clove, eucalyptus, fennel, frakincense, ginger, lavender, lemon, neroli, myrrh, orange, peppermint, pine, rose, sandlwood, tea-tree and thyme. It must be remembered that volatile oils can contain over 100 constituents , must in very small amounts, and the principal components might not be those giving the oil its unique characteristic.