VOLATILE OILS.

VOLATILE OILS

VOLATILE OILS All official volatile oils are of vegetable origin.
Normally pre-exist in the plant – stored in a special secretory tissue (e.g. Citrus peel oil cells or oil ducts in umbelliferous fruits). EXCEPTION: Oil of bitter almond – formed by hydrolysis of the glycosides.

USES OF VOLATILE OILS Therapeutically (Oil of Eucalyptus)
Flavouring (Oil of Lemon) Perfumery (Oil of Rose) Starting materials to synthesize other compounds (Oil of Turpentine) Anti-septic – due to high phenols (Oil of Thyme). Also as a preservative (oils interfere with bacterial respiration) Anti-spasmodic (Ginger, Lemon balm, Rosemary, Peppermint, Chamomile, Fennel, Caraway) Aromatherapy

DEFINITION OF VOLATILE OILS
Volatile oils are products which are generally complex in composition, consisting of the volatile principles contained in plants, and are more or less modified during the preparation process. Only 2 procedures may be used to prepare official oils Steam distillation Expression 4 Main types of volatile oils Concretes Pomades Resinoids Absolutes

CONCRETES Prepared from raw materials of vegetable origin (bark, flowers, leafs, roots etc.) Extracted by HC type solvents, rather than distillation or expression – Becomes necessary when the essential oil is adversely affected by hot water or steam (e.g. jasmine). Produces a more true-to-nature fragrance.

CONCRETES Concretes contain about 50 % wax and 50 % essential oil (jasmine). Ylang ylang (concrete volatile) contains 80 % essential oil and 20 % wax. Advantages of concretes: they are more stable and concentrated than pure essential oils.

POMADES True pomades are (volatile oil) products of a process known as enfleurage (hot or cold). Enfleurage is used for obtaining aromatic materials from flowers containing volatile oils to produce perfume long after they were cut.

ENFLEURAGE: METHOD A glass plate is covered with a thin coating of especially prepared and odourless fat (called a chassis). The freshly cut flowers are individually laid on to the fat which in time becomes saturated with their essential oils. The flowers are renewed with fresh material. Eventually the fragrance-saturated fat, known as pomade, may be treated with alcohol to extract the oil from the fat.

RESINOIDS Prepared from natural resinous material (dried material) by extraction with a non-aqueous solvent, e.g. Petroleum ether or hexane. E.g. Balsams – Peru balsam or benzoin; resins (amber or mastic); Oleoresin (copaiba balsam and turpentine); Oleogum resins (frankincense and myrrh)

RESINOIDS Can be viscous liquids, semi-solid or solid.
Usually homogeneous mass of non-crystalline character. Uses: in perfumery as fixatives to prolong the effect of a fragrance.

ABSOLUTES Obtained from a concrete, pomade, or a resinoid by alcoholic extraction. The extraction process may be repeated. The ethanol solution is cooled & filtered to eliminate waxes. The ethanol is then removed by distillation. They are usually highly concentrated viscous liquids.

Fx OF VOLATILE OILS In most cases, the biological function of the terpenoids of essential oils remains obscure – it is thought that they play an ecological role – protection from predators & attraction of pollinators.

LOCALIZATION Synthesis & accumulation of essential oils are generally associated with the presence of specialized histological structures, often located on or near the surface of the plant: - Oil cells of Zingiberaceae - Glandular trichomes of Lamiaceae - Secretory cavities of Myrtaceae or Rutaceae - Secretory canals of Apiaceae or Astereraceae (Compositeae)

VOLATILE OIL COMPOSITION
Mixtures of HC’s and oxygenated compounds derived from these HC’s. Oil of turpentine – mainly HC’s Oil of Clove – mainly oxygenated compounds EXCEPTION: Oils derived from glycosides (e.g. bitter almond oil & mustard oil). Oxygenated compounds – responsible for the odour/smell of the oil. They are slightly water soluble – Rose water & Orange Water; more alcohol soluble. Most volatile oils are terpenoid. Some are aromatic (benzene) derivatives mixed with terpenes. Some compounds are aromatic, but terpenoid in origin (e.g. Thymol – Thyme)

CHEMICAL COMPOSITION Volatile oils are divided into 2 main classes based on their biosynthetic origin Terpene derivatives (formed via the acetate mevalonic acid pathway) Aromatic compounds (formed via the shikimic acid-phenylpropanoid route) Miscellaneous Origin

Volatile oils different from fixed components of plants that are
highly odiferous generally occur as they are secreted in oil cells in specialised structures ducts, cavities, glandular hairs frequently associated with other substances gums, resins (resinify on exposure to air) mainly terpenoid some phenol ethers and phenols

Terpenoids based on the 5C isoprene unit Monoterpenes
most important, most volatile di-, tri-, sesquiterpenes also important contain 2 condensed 5C units head-tail most formed from geranyl pyrophosphate

Monoterpene components
Hydrocarbons Alcohols

Aldehydes all produced via the terpenoid pathway Ketones Citral

Esters Oxides

Sesquiterpenes (C15) Hydrocarbons Phenols Phenolic esters Anethole

Chemical and physical properties
volatile liquids with no colour keep in amber bottles with minimum air odour asymetric centres, isomers with optical activity only one isomer occurs naturally refractive index normally high is a means to characterise the oil miscible in water and soluble in organic solvents more soluble if contains –OH fatty acids reasonably heat stable can be steam distilled tend to be used as solvents for resins

Families Economically only a few family groups are commercially useful
[1] Labiatae Lavender, Mentha Sp. large number, tend to hybridise oil occurs in special organs synthesized in glandular trichomes (mint) burst easily releasing oil [2] Umbelliferae Fruits (best if ripe): anise, caraway, fennel, coriander found in “vittae” in the outer layer is characteristic steam distill to remove oils

[3] Pinaceae [4] Rutaceae [5] Lauraceae Pine, juniper Citrus fruits
found in resin ducts in outer old xylem or bark released when bark removed [4] Rutaceae Citrus fruits typical ductless sacs in outer part of fruit – rind found at various depths before albino layer (white bitter pithy part) oil is there under pressure and will burst open when ‘rasped’ less stable, need more care [5] Lauraceae Cinnamon, camphor from region immediately below bark

Method of extraction depends where oils lies and its stability
Steam distillation gentle, herb + water heated and oil distilled over Water distillation wood chips in chamber and heated until water distills over crushed sample must be stable Cold expression citrus fruit oil (lemon, orange, bergamot) rasping process breaks oil sacs in rind pour cold water over and then separate oil and water

Destructive distillation
Enfleurage petals (rose) placed between glass sheets covered in sheep or pig fat oil seeps into fat and can be extracted with methanol Destructive distillation produces a different product from the one started with pine and juniper heated to exclude air over aqueous part - wood naphtha (ethanol and crude acetic acid) to attract juniper oil non-aqueous part – resin (pine tar) to attract C5-C20 molecules including monoterpenes like a fractional distillation Menthol and camphor nearly solid at room temperature can isolate by freezing oils out cheaper to synthesize camphor but generally extracted from plants camphor

Uses [1] Flavours & carminatives Labiatae
as inhalations, orally, gargles, mouthwashes, trans-dermally [1] Flavours & carminatives Labiatae Mentha piperita (peppermint oil) 50-75% menthol, also contains menthone etc used mainly in toothpastes Mentha spicata (spearmint oil) 50-75% L-carvone some minor components similar to peppermint but major components differ giving different smell and taste Lavendura officinalis (lavender oil) 35-45% linalyl acetate, also geraniol, limonene, cineole some varieties have a lower % so other compound characteristics dominate growing environment will affect quality

Rutaceae Umbelliferae Citrus oils Citrus flower oils
D-limonene 90%, citral 4% + esters, pinene, d-limonene (small amount) high proportion of limonene desirable but a lot is removed after isolation by distillation under reduced pressure leaves oil high in citral which deteriorates on storage giving a turpentine odour Citrus flower oils no citral, other constituents that give a different odour and flavour of orange flower oil used in confectionary Umbelliferae Pimpinella anisum (anise), Foeniculum vulgare (fennel) 90% anethole some fennel variaties contain fenchone giving a bitter taste Carum carvi (carraway) carvone Coriandum sativum (coriander) 60-80% linalool

[2] Local stimulants and antiseptics
(containing phenols) Pinaceae Pinus paulastrus destructive distillation phenol p-cresol Juniperus oxycedrus cadenine Clove Syzygium aromaticum eugenol 82% used on sore teeth to deaden pain Eucalyptus oil 1,8-cineole 70% (sesquiterpene)

[4] Insect repellant, antimating device
[3] Perfumes Rose oil Rosa gallica, R. damescena trans-geraneol and isomer cis-nerol Lavender oil Citrus oil [4] Insect repellant, antimating device Citronella oil from grass doesn’t work well [5] Starting materials Turpentine (for synthesis of other compounds)

A. TERPENES Terpenes, or terpenoids, are the largest group of secondary products (metabolites). They are all formed from acetyl CoA or glycolytic intermediates.

CLASSIFICATION OF TERPENES
All terpenes are formed from 5-C elements Isoprene is the basic structural element.

CLASSIFICATION OF TERPENES
Terpenes are classified by the number of 5-C atoms they contain 10-Carbon terpenes (contain 2 C-5 units) – monoterpenes 15- Carbon terpenes (3 C-5 units) are called sesquiterpenes. 20-carbon terpenes (4 C-5 units) are diterpenes. Larger terpenes (30 Carbons) are called triterpenes (triterpenoids), 40 Carbons – called tetraterpenes and polyterpenoids.

TERPENOIDS Terpenoids contain only the most volatile terpenes (i.e. molecular weight is not too high)  mono and sesquiterpenes May occur as oxygenated derivatives, e.g. alcohols, aldehydes, ketones, phenols, oxides & esters.

EXAMPLES OF TERPENES LIMONENE MENTHOL BORNEOL SESQUITERPENES

i. LIMONENE Structural classification: Monocyclic terpene
Functional Classification: Unsaturated HC Occurrence: Citrus fruit

ii. MENTHOL Structural classification: Monocyclic with hydroxyl group
Functional classification: Alcohol Occurrence: Peppermint

iii. BORNEOL Functional Classification: //// Occurrence: Cinnamon

iv. SESQUITERPENES (Contain 3 isoprene units) Acyclic – E.g. Farnesol
Monocyclic – E.g. Bisobolol Bicyclic e.g. Chamezulene (Chamomile)

B. AROMATIC COMPOUNDS Many are phenols are phenol esters E.g. Vanillin

PROPERTIES OF VOLATILE OILS
Almost entirely volatile without decomposition. Density: Most are less than 1g/ml. 2 are heavier – Oil of Cinnamon and Clove oil. Soluble in ether, chloroform & alcohol. Slightly soluble in water: give it a characteristic odour & taste. Leaves a temporary translucent stain on paper which disappears as the oil volatilizes. Most are colourless. Oxidize on exposure to air and resinify  colour becomes darker (odour changes slightly). All are characteristic odours. Most are optically active.

PRODUCTION OF ESSENTIAL OILS
Essential oils may be produced By steam - Simple steam distillation - Saturated steam distillation - Hydrodiffusion By expression Other Methods Concretes & Resinoids may be produced By solvent extraction By methods using oils & fats By extraction by supercritical gasses

ESSENTIAL OILS: i.STEAM DISTILLATION
a. SIMPLE STEAM DISTILLATION Plant material is immersed directly in a still filled with water. This is then brought to a boil. Heterogeneous vapours are condensed on a cold surface. Essential oil separates based on difference in density and immiscibility.

b. SATURATED STEAM Plant does not come into contact with the water  steam is injected through the plant material placed on perforated trays. It is possible to operate under moderate pressure. Advantages: Limits the alteration of the constituents of the oil It shortens the duration of the treatment It conserves energy It can also be conducted on on-line in automated set ups.

c. HYDRODIFFUSION Pulses of steam is sent through the plant material at very low pressure from (top to bottom). ADVANTAGE: Normally produces a product of high quality. Saves time and energy.

EXPRESSION (E.G.OF CITRUS EPICARPS)
The rind is lacerated, and the contents of the ruptured secretory cavities are recovered. CLASSIC PROCESS: an abrasive action is applied on the surface of the fruit in a flow of water. The solid waste is eliminated, and the essential oil separated from the aqueous phase by centrifugation. OTHER machines break the cavities by depression, and collect the essential oil directly  prevents the degradation linked to the action of water.

EXPRESSION OF CITRUS EPICARPS
Most facilities allow for the simultaneous or sequential recovery of the fruit juice and of the essential oil, by collecting the oil with a spray of water after the abrasion (scarification – puncture by pins) before or during the expression of the fruit juice. Enzymatic treatment of the residual water allows recycling, and markedly increases the final yield of essential oil. Citrus oils are also obtained directly from the fruit juices (by vacuum de-oiling)

iii. OTHER METHODS Steam distillation by microwaves under vacuum. In this procedure, the plant is heated selectively by microwave radiation in a chamber inside which the pressure is reduced sequentially. fresh plants require no added water. ADVANTAGE: This method is fast, consumes little energy and yields a product which is most often of a higher quality than the traditional steam distillation product.

PRODUCTION OF CONCRETES & RESINOIDS
SOLVENT EXTRACTION Extraction is generally preceded by a process of: bruising the fresh, wilted or semi-desiccated organs, chopping herbaceous drugs, pounding roots & rhizomes or turning wood into chips or shavings. The procedure is conducted in specialized facilities e.g. Soxhlet-type extractor.

SOLVENT EXTRACTION The solvent selection is influenced by technical & economical factors - Selectivity (being a good solvent for the specific constituents). - Stability (chemical inertness) - Boiling point should not be so high that the solvent can be completely eliminated; nor too low, to limit losses & control cost - Handling safety Solvents most used are aliphatic HC’s – petroleum ether, hexane, propane & liquid butane. Although benzene is a good solvent, its toxicity increasingly limits is use.

SOLVENT EXTRACTION At the end of the procedure, the solvent contained in the plant material is recovered by steam injection. Main disadvantages of solvent extraction - Lack of selectivity, many lipophilic substances may end up in the concretes & render further purification necessary. - The toxicity of solvents  leads to the restrictive regulations regarding their use - Residues in the final product.

ii. METHODS USING OILS & FATS
These procedures take advantage of the liposolubility of the fragrant components of plants in fats. a. “Enfleurage” – the plant material is placed in contact with the surface of the fat. Extraction is achieved by Cold diffusion into the fat Digestion – carried out with heat, by immersing the plant in melted fat (also known as hot enfleurage). The final product is known as a floral pomade.

METHODS USING OILS & FATS
b. PNEUMATIC METHOD: similar in principle to the enfleurage process. It involves the passage of a current of hot air through the flowers. The air, laden with suspended (extracted) volatile oil, is then passed through a spray of melted fat in which the volatile oil is absorbed.

iii. EXTRACTION BY SUPERCRITICAL GASSES
Beyond its critical point, a fluid can have the density of a liquid & the viscosity of a gas  therefore diffuses well through solids, resulting in a good solvent. CO2 is the main gas used Advantages of CO2 - It is a natural product - chemically inert, non-flammable - non-toxic - easy to completely eliminate - selective - readily available - Inexpensive

EXTRACTION BY SUPERCRITICAL GASSES
DISADVANTAGE: Technical constraints - High cost of initial investment ADVANTAGES: - obtain extracts which are very close in composition to the natural product. - It is possible to adjust the selectivity & viscosity, etc by fine tuning the temperature & pressure - All result in the increase of popularity of this type of method

EXTRACTION BY SUPERCRITICAL GASSES
USES Initially developed to decaffeinate coffees, prepare hops extracts or to remove nicotine from tobacco, the method is now used to - Prepare spice extracts (ginger, paprika, celery) - Specific flavours (black tea, oak wood smoke) - Plant oils - To produce specified types of a certain product, e.g. thujoneless wormwood oil.

TREATMENTS OF THE OILS Occasionally it is necessary to decolourize, neutralize or rectify the oils obtained. Steam jet under vacuum Allows for the elimination of smelly or irritating products, and to obtain a final product of desired “profile”. Chromatrographic techniques This permits a good separation of the essential oil from non-volatile lipophilic compounds.

VARIABILITY FACTORS OF ESSENTIAL OILS
Occurrence of Chemotypes Influence of the vegetative cycle Influence of environmental factors Influence of preparation method

i. CHEMOTYPES Chemical breeds commonly occur in plants containing volatile oils, e.g. Thyme (Thymus vulgaris) – has 7 different chemotypes, each with slightly different types & amounts of volatile oils.

ii. THE VEGETATIVE CYCLE
Proportions of the different constituents of a volatile oil may vary greatly throughout its development. Wide ranges are commonly found in fennel, carrot and coriander (linalool is higher in ripe fruit than unripe fruit). Mentha (peppermint) is also greatly affected by the vegetative cycle.

iii. ENVIRONMENTAL FACTORS
Temperature, humidity, duration of daylight (radiation), and wind patterns all have a direct influence on volatile oil content, especially in those herbs that have superficial histological storage structures (e.g. glandular trichomes). When the localization is deeper, the oil quality is more constant.

ENVIRONMENTAL FACTORS
e.g. Peppermint: long days & temperate nights  higher yields of oil & menthofuran. Cold nights lead to an increase in menthol. Laurus nobilis (Bay) [volatile oil] is greater in the southern hemisphere than the northern. Citrus: higher temperatures = higher oil content.

ENVIRONMENTAL FACTORS
Cultivation practices also play an important factor to the yield & quality of the final product. Fertilization and the amounts of N, P and K have been studied for various species. The watering regiment also plays an important role.

PREPARATION METHOD Because of the volatile nature of the constituents of essential oils, the composition of the product obtained by steam distillation is often different from the constituents originally found in the secretory organs of the plant. During steam distillation, the water, acidity and tempereature may induce hydrolysis of the esters. Rearrangements, isomerizations, racemiazations, oxidations and other reactions also occur, all of which change the composition.

GINGER: Zingiber officinale
Definition: Ginger is the peeled or unpeeled rhizome of Zingiber officinale (Zingiberaceae). Common Names: Jamaican ginger, Ginger

Zingiber officinalis - Ginger
GEOGRAPHICAL SOURCES Jamaica China India Africa HISTORY Cultivated in India from the earliest times. Used by Greeks and Romans and was a common article of commerce in the European Middle Ages.

CULTIVATION & PREPARATION
Grows well in subtropical temperatures with high rainfall. Grown by vegetative means. Mulching or is necessary as the plant rapidly exhausts minerals from the soil. When the stems wither, the rhizomes are ready for collection. Dried.

MACROSCOPICAL FEATURES
Scraped/peeled herb has little resemblance to the fresh herb (loss in weight & shrinkage). Occurs in branched pieces “hands” or “races”. Buds No cork Aromatic odour & pungent taste. Unscraped rhizome: resembles scraped herb – Covered with cork (brownish layers)

MICROSCOPICAL FEATURES
Cork cells – high starch content Cork cells are absent in the scraped drug. Outer zone of flattened parenchyma & inner zone of normal parenchyma. Oil cells scattered in the cortex.

Zingiber officinale - CONSTITUENTS
Volatile oils (1 – 2%) Camphene Cineole Citral Borneol Gingerol – pungent component – Anti-inflammatory Shogaols – increases bile secretion Sesquiterpene HC’s Zingiberene & Zingiberol (Sesquiterpene alcohol) Resins Starch Mucilage

Zingiber officinale VARIETIES ALLIED DRUGS ADULTERANTS
Chinese Ginger – sliced African ginger – darker (cortex is grey – black in colour); lacks the odour but more pungent than Jamaican herb. ALLIED DRUGS Japanese ginger – Z. mioga Preserved ginger – undried rhizomes preserved by boiling in syrup. ADULTERANTS Spent ginger Vegetable adulterants (detected with microscopical examination).

USES & ACTIONS ACTIONS Carminative Stimulant Anti-emetic
Anti-bacterial & Anti-fungal Sesquiterpene lactones – Anti-ulcer Gingerol – pungent component – Anti-inflammatory Shogaols– increases bile secretion & enhanced GIT activity USES Motion Sickness Morning Sickness

CARDAMOM FRUIT & OIL DEFINITION: Cardamom consists of the dried, nearly dried ripe fruits of Elettaria cardamomum var miniscula (Zingiberaceae). PARTS USED: Seeds (should be kept in the fruit until ready to be used – Prevents loss of volatile oils). (3RD most expensive spice).

Elettaria cardamomum GEOGRAPHICAL SOURCES HISTORY Sri Lanka India
Guatemala HISTORY Traditional Indian ceremonies

PRODUCTION, COLLECTION & PREPARATION
Mainly obtained from cultivated plants (propagated by seedlings or vegetatively [problematic due to virus infection]). Capsules on the same plant ripen at different times – important to collect them before they split.

COLLECTION & PREPARATION
Fruits are dried slowly (outdoors or indoors). Too rapid drying – capsules split & shed seeds Calyx at the apex of the stalk and the stalk at the base may be removed. Fruits are graded with a sift into ‘longs’, ‘mediums’, ‘shorts’ & ‘tiny’. If they have been sulphur – bleached (improved colour), it will be aired outdoors before packed for transport.

Plant is reed-like - > 4 m, with long leaves growing from the rhizome. Fruits – capsular: inferior, ovoid, 1-2 cm long. Apex: shortly beaked & shows floral remains. Base: rounded & shows the remain of a stalk. Internally the capsule is 3-celled; each cell contains x2 row of seeds. Each seed: Slightly angular, 4mm long & 3 mm broad. Colour: dark red-brown (fully ripe seeds)  paler in unripe seeds. Strong, pleasant, aromatic odour Pungent taste

Oil cells Predominant Parenchyma (yellow colour) Cells containing silica Starch grains

VARIETIES & ADULTERANTS
ADULTERATION Powdered drug adulterated with the fruit pericarp (powdered). ALLIED HERBS Official variety – E. cardamomum var miniscula Other: E. cardamomum var major (more elongated & sometimes 4 cm long with dark brown pericarps) Amomum aromaticum (Bengal cardamom) Amomum subulatum (Nepal cardamom) Amomum cardamomum (Java cardamom)

CHEMICAL CONSTITUENTS
2.8 – 6.2 % volatile oil Abundant starch (up to 50%) Fixed oil (1 – 10%) Calcium oxalate

Elettaria: ACTIONS & USES
Flavouring agent (curries & biscuits) Liqueur manufacture Small amount is used for pharmaceutical manufacture (Compound Tincture of Cardamom).

CINNAMON: Cinnamomum zeylanicum
DEFINITION: Cinnamon is the dried bark of Cinnamomum zeylanicum (Lauraceae). GEOGRAPHICAL SOURCES Cultivated in Sri Lanka, South India, Seychelles, Madagascar, Martinique, Cayenne, Jamaica & Brazil.

CULTIVATION, COLLECTION & PREPARATION
Grown from seed Cut down when 2-3 years old. After 5-6 shoots grow from the stump (18 months), shoots are harvested, trimmed and fermented. Bark is removed. Peeled bark is then stretched over a suitable stick Outer cortex is removed.

PREPARATION OF Cinnamomum
Individually scraped barks are placed inside each other. Compound quills are dried on wooden frames in the open air without exposure to direct sunlight. Sorted into grades.

Normally received in shorter lengths known as ‘cigar lengths’. Consists of a single or double compound quill about 6-10 mm diameter of varying length. Thickness of the quill varies according to grade (good quality: Not > 0.5mm), bark: mm. External surface: is yellow-brown, shining, wavy lines (pericycle fibres) and occasional scars & holes (leave/twig positions). Inner surface: darker, longitudinally striated. Odour: fragrant Taste: Warm, sweet & aromatic

Transverse: absence of epidermis & cork Sclereids (thickened lignified pitted walls) Secondary phloem is composed of phloem parenchyma containing oil & mucilage cells, phloem fibres & medullary rays. Some phloem parenchyma contain tannins. Secretion cells: volatile oils and mucilage Calcium oxalates

Cinnamomum - CONSTITUENTS
Volatile oils (at least 1.2 %) Phlobaphenes Mucilage Calcium Oxalate Starch

CINNAMON OIL – ADULTERATION & ALLIED HERBS
Adulterants Cinnamon Leaf Oil Oil of Cassia Allied Herbs Cayenne Cinnamon – C. zeylanicum grown in Brazil – not used in Britain C. loureirii – from Vietnam – Closely resembles C. cassia

Cinnamomum zeylanicum - USES
Flavouring agent Mild astringent Oil: Carminative Germicide

LEMON PEEL Definition: Dried lemon (Limonis Cortex) peel is obtained from the fruit of Citrus limon (Rutaceae). Botanical Description: Small tree, growing to 3-5 m in height. Geographical Sources Mediterranean Regions

Limonis Cortex – COLLECTION & PREPARATION
Lemons are collected in January, August & November, before the green colour changes to yellow. The smaller fruit, which would not be sold on the produce market, are used in the preparation of oil of lemon - the peel is removed with a sharp knife in the form of a spiral band.

Limonis Cortex – CHARACTERISTICS
Dried lemon peel occurs in spiral bands (2 cm wide; 2-3 mm thick). The outer surface is rough & yellow; the inner surface is pulpy & white (anatomically similar to that of an orange peel). Odour: Strong & characteristic Taste: aromatic & bitter

Limonis Cortex – CONSTITUENTS & USES
Should contain at least 2.5% volatile oil Vitamin C Hesperidin (Flavonoid) Mucilage Calcium Oxalate USES Flavouring purposes

LEMON OILS - Oleum limonis
Definition: Lemon oil is the oil expressed from the outer part of the fresh pericarp of the ripe or nearly ripe fruit of Citrus limon (Rutaceae). BP: oil should be obtained by suitable mechanical means, without the use of heat, from the fresh peel. Much oil is derived via steam distillation, but this process yields oil of inferior quality. Distilled oil of lemon is much cheaper than that prepared by expression. Large amounts are used for non-pharmaceutical purposes. Geographical Sources: Mediterranean, North & South America, Australia & parts of Africa.

Preparation of Lemon Oils
i. Hand Methods No longer applicable to pharmaceutical oils

Production of Lemon Oils
Machine Processes Quality is inferior to the best hand-pressed oils. Machines are designed to release oils from the peel via puncture, rasting or cutting and by imitating the gentle squeezing action of the sponge method. (Superiority of the sponge method is due to the fact that there is no contact between the oil & the inner white part of the skin. The newer machines extract oil more completely than the older ones and give a higher yeild Distilled Oils Although not official, some lemon oils are produced by distillation, mainly from the residue of the expression processes. It is much cheaper than hand-pressed or machine-made oil.

Oleum limonis - CONSTITUENTS
Terpenes – mainly limonene Sesquiterpenes Aldehydes (Citral & Citronella) Esters Lemon oil has a tendency to resinify and should be protected from the action of air & light as much as possible.

Oleum limonis – ADULTATION & USES
ADULTERATION Oil of turpentine Terpenes from ‘terpeneless oil of lemon’ Distilled oil of lemon Oil of lemon-grass USES Perfumery Flavouring

TERPENELESS LEMON OIL Definition: Oil prepared by concentrating lemon oil in vacuum until most of the terpenes have been removed, or by solvent partition. The concentrate is a terpeneless oil, which has a citral content of %. It is equal in flavouring to times its volume of lemon oil

BUCHU – Agathosma betulina

Agathosma betulina – CONSTITUENS & USES
CONSTITUENTS Volatile oils Pulegone Menthone & isomenthone limonene Diosmin Mucilage Resin Calcium oxalates Buchu camphor – Responsible for the diuretic action USES/ACTIONS Diuretic Urinary Tract Anti-Septic – Used for UTI’s

NUTMEG & NUTMEG OIL Definition: Nutmeg is the dried kernel of the seed of Myristica fragrans (Myristicaceae). Geographical Sources Indigenous to the Molucca Islands (Spice Islands) Cultivated in Indonesia, Malaysia & the West Indies.

NUTMEG – Myristica fragrans
HISTORY First Introduced to the Europeans by the Arabs. Portuguese lost control of the spice trade to the Dutch, who maintained complete monopoly by destroying all trees in the neighbouring islands & preventing the export of living seeds.

CULTIVATION, COLLECTION & PREPARATION
Trees can be grown from fresh seed gown in the shell. The seeds germinate after about 5 weeks. When the plants are 6 months old, they are transplanted to the fields. Nutmegs are dried in the shells (process differs according to local conditions). Normally they are dried in the sun & covered at night & rainy weather. They can also be dried in the oven or over low flames. When completely dried, the kernel rattles in the testa, which is then cracked & the nutmeg extracted.

Nutmeg trees are evergreen, growing up to 20 m in height. Nutmegs are oval, 2-3 cm long & 2 cm broad. If not heavily limed, the surface is a brown or grey brown in colour. Odour: Strong & aromatic Taste: Pungent and slightly bitter.

Potassium acid tartrate crystals Parenchym with thin brown walls Oval oil cells Feathery crystals of fat Few tannin cells (containing tannin & starch)

NUTMEG – ALLIED HERBS Papua nutmegs – from M. argentea (New Guinea) – little odour & a disagreeable taste. Bombay nutmegs – M. malabarica (India) – lack the characteristic odour of the genuine herb.

NUTMEG OIL Nutmeg oil is distilled from the kernels of Myristica fragrans. CONSTITUENTS Pinene Sabinene Camphene Dipentene Safrole Eugenol & eugenol derivatives Myristicin – a benzene: toxic to humans (large does of nutmeg or nutmeg oil may cause convulsions).

MACE Common mace or Banda mace consists of the dried arillus or arillode of M. fragrans. Description: bright red colour & lacks in aroma.

MACE – CONSTITUENTS & USES
Volatile oils (similar to that of nutmeg) – eugenol derivatives are the main active constituents – responsible for the anti-bacterial effects. Also has 2 anti-microbial resorcinols (Malabaricone B and C) Nutmegs, maces & their oils, are all used for Carminatives Flavouring Infantile Diarrhoea (Tea of nutmeg – Ayurveda).

CLOVE DEFINITION: Cloves are the dried flower buds of Syzygium aromaticum (Eugenia caryophyllus), (Myrtaceaea). Geographical Sources Molucca or Clove Islands, Zanzibar, Pemba, Madagascar, Indonesia & Brazil.

HISTORY OF CLOVE Cloves were used in China as early as 266 BC, and by the 4th century, they were known in Europe, although very expensive. Same as with nutmeg, the Dutch also destroyed all trees from surrounding native islands to secure a monopoly, and cultivated them only in a small group of islands. In 1770, the French managed to introduce clove trees to Mauritius, and started cultivating them there, as well as in Zanzibar, Penang and Sumatra.

COLLECTION & PREPARATION
The flower buds are collected when the lower part turns green-crimson. The cloves are dried in the open air on mats & separated from their peduncles (forming clove stalks which are also sold commercially). If left on the tree for too long, the buds open & the petals fall, leaving “brown cloves”. Later the fruits (“mother cloves”) are produced.

Cloves are mm long. The head consists of 4 slightly projecting calyx teeth, 4 membranous petals and numerous incurved stamens around a large style. Odour: Spicy & Pungent Taste: Aromatic

Heavy cuticularized epidermis Numerous oil cells (shizolysigenous) Calcium oxalates (cluster crystals & prisms) Stomata (epidermis of sepals) Starch (Fruit – “mother cloves”) Lignified sclereids

CONSTITUENTS 14-21% Volatile oils Mainly eugenol & isoeugenol
Sitosterol Stigmasterol Campesterol Tannins Triterpene acids & esters Glycosides

USES OF CLOVE Stimulant aromatic Spice
For the preparation of volatile oil Sesquiterpenes: potential anti-carcinogenic compounds

CLOVE OIL Oil distilled in Europe and the US normally does not need purification, while oil distilled in other areas (e.g. Madagascar) does. After purification the oil is sold with varying eugenol contents. Oil of cloves is yellow or colourless, is slightly heavier than water.

CLOVE OIL - CONSTITUENTS
Volatile oils – mainly eugenol & acetyleugenol Sesquiterpenes (α and β caryophyllenes) Oil of clove – like other volatile/essential oils – should be stored in a well-fitted, air-tight container, & should be protected from light & heat.

CLOVE OIL - USES Anti-septic Aromatic Stimulant Flavouring Agent

EUCALYPTUS LEAF DEFINTION: Eucalyptus leaf consists of the whole or cut dried leaves of the older branches of Eucalyptus globulus, (Myrtaceae). GEOGRAPHICAL SOURCES Portugal, SA, Spain, China, Brazil, Australia, India & Paraguay.

Eucalyptus - DESCRIPTION
MACROSCOPICAL Older dried leaves are grey-brown & have lateral veins. Secretory oil cells are visible in leaves held to the light. MICROSCOPIC Epidermal cells have a thick cuticle. Anisocytic stomata Mesophyll has schizogenous oil glands Calcium oxalate crystals: Prisms & Cluster crystals

Eucalyptus - CONSTITUENTS
Volatile Oil (at least 2 %) sesquiterpene - Anti-bacterial action against oral pathogens.

EUCALYPTUS OIL Oil of eucalyptus is distilled from the fresh leaves of various species of Eucalyptus and rectified. They are produced in the same countries which produce the dry herb. Only a certain amount of species produce oil suitable for medicinal use – the main criteria is a high cineole content and low amounts of phellandrene and aldehydes. Suitable oils are obtained from E. polybractea, E. smithii, E. globulus and E. australiana.

CHARACTERISTICS & CONSTITUENTS
Colourless or pale yellow liquid Aromatic & camphoraceous in odour. Pungent & camphoraceous in taste, which is followed by a sensation of cold. CONSTITUENTS At least 70 volatile oils (mainly cineole).

EUCALYPTUS OIL - USES Alleviating the symptoms of nasopharyngeal infections Treating coughs Decongestant. Official preparations Mixtures, inhalations, lozenges and pastilles; also applied externally as ointments and liniments.

FENNEL DEFINITION: Fennel consists of the dried ripe fruits of Foeniculum vulgare (Umbelliferae). GEOGRAPHICAL SOURCES Europe, India, China & Egypt. Mediterranean origin.

ACTIVE CONSTITUENTS 1-4 % Volatile oil trans-anethole Antethole
Estragole Fenchone Flavonoids Coumarins Glycosides

ACTIONS & USES ACTIONS Carminative Expectorant Aromatic USES
- All due to anethole (and fenchone) USES Flatulence Dyspepsia Chronic coughs & catarrh

Foeniculum vulgare

Foeniculum vulgare – USES
Culinary purposes Used in medicine as a flavouring Carminative

CARAWAY & CARAWAY OIL DEFINITION: Caraway consists of the dried, ripe fruits of Caram carvi (Umbelliferae). GEOGRAPHICAL SOURCES Wild & Cultivated in Central & Northern Europe, Holland, Denmark, Germany, Russia, Finland, Poland, Hungary, Britain, Egypt, Morocco, Australia & China

A biennial herb growing up to 1 m in height. Herb: Normally consists of mericarps separated from the pedicels. Fruits are slightly curved, brown & glabrous. Size: 4-7 mm long, 1-3 mm wide Often the stigma & style are still attached. Characteristic aromatic odour & taste

Pitted sclerenchyma secretory canals Dark, red-brown cells containing a pale yellow or colourless oleoresin Thick cellulose walls Calcium oxalate crystals

ACTIVE CONSTITUENTS 1-7 % Volatile oils Carvone Limonene Carveole
8-20 % Fixed oils Proteins Calcium oxalates Colouring matter Resin

CORIANDER & CORIANDER OIL
DEFINITION: Coriander is the dried, nearly ripe fruit of Coriandrum sativum (Umbelliferae). GEOGRAPHICAL SOURCES Indigenous to Italy. Also cultivated in Holland, Central & Eastern Europe, Mediterranean (Morocco, Malta & Egypt), China, India & Bagladesh.

Annual herb growing 0.7 m in height with white or pink flowers. Drug: Normally consists of whole cremocarps – straw yellow & 2-4 mm in diameter when ripe. Considerable variation occurs (e.g. Indian variety > oval). Apex has 2 styles. Fruits have an aromatic odour & spicy taste. Unripe plant: unpleasant mousy odour  same odour oil has when made from unripe fruit.

Outer pericarp: stomata & calcium oxalte prisms. Thick sclerenchyma Testa:= brown flattened cells Endosperm is curved & consists of parenchymous cells containing fixed oils.

ACTIVE CONSTITUENTS 1.8 % Volatile oils Linalool/coriandrol Pinene
Terpinene Limonene Cymene Non-linalool alchols & esters Flavonoids Coumarins Phenolic acids High fat content (16-28%) Protein (11-17%)

Coriandrum sativum - USES
Domestic purposes (cooking - curries) Pharmaceutically: flavouring agent & Carminative

PEPPERMINT & PEPPERMINT OIL
DEFINITION: Peppermint is the dried leaves of Mentha piperita (Labiate). It should contain at least 1.2 % volatile oil. GEOGRAPHICAL SOURCES: Europe & America

All mints have a square stem & creeping rhizome. Black mint, which is the most commonly cultivated variety in England, has purple stems and dark green petiolate leaves tinged with purple. Leaf blades are 3-9 cm long with a grooved petiolate up to 1 cm long. Pinnate venation. Glandular trichomes: bright yellow points (hand lens) Small purple flowers appear in late summer.

MICROSCOPIC FEATURES Diacytic stomata Multicellular clothing trichomes
2 types of glandular trichomes (one with a unicellar head; with a multicellular head). Calcium oxalate is absent.

Oleum Menthae Oil of peppermint is obtained from Mentha piperita via steam distillation using the flowering tops. Oil should contain at least 44 % menthol, & menthone and % menthyl acetate.

Oleum Menthae - CONSTITUENTS
Menthol Menthone & isomenthone Menthyl acetate Limonene Cineole Menthofuran Pulegone OIL COMPOSITION: greatly influenced by genetic factors & seasonal variation.

PEPPERMINT & PEPPERMINT OIL USES
OIL: anti-bacterial, cooling, carminative HERB: Carminative

LESSON TAKE-AWAY Definitions of Volatile Oils
Methods of Production of Volatile Oils Herbs containing Volatile Oils

VOLATILE OILS.

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