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 oilsi. Steam distillationii. Expression

4 Main types of volatile oilsiii. Concretesiv. Pomadesv. Resinoidsvi. Absolutes

CONCRETESPrepared 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.

CONCRETESConcretes 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: METHODA 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.

ABSOLUTESObtained 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

i. Terpene derivatives (formed via the acetate mevalonic acid pathway)

ii. Aromatic compounds (formed via the shikimic acid-phenylpropanoid route)

iii. Miscellaneous Origin

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) – monoterpenes15- 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

i. LIMONENE

ii. MENTHOL

iii. BORNEOL

iv. 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 i. By steam

- Simple steam distillation- Saturated steam distillation- Hydrodiffusion

ii. By expressioniii. Other Methods

Concretes & Resinoids may be producediv. By solvent extractionv. By methods using oils & fatsvi. By extraction by supercritical gasses

ESSENTIAL OILS: i.STEAM DISTILLATION

a. SIMPLE STEAM DISTILLATIONPlant 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 treatmentIt conserves energyIt 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.

ii. 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

i. SOLVENT EXTRACTIONExtraction 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 EXTRACTIONThe 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 usedAdvantages 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

USESInitially 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.

i. Steam jet under vacuumAllows for the elimination of smelly or irritating

products, and to obtain a final product of desired “profile”.

ii. Chromatrographic techniquesThis permits a good separation of the essential oil

from non-volatile lipophilic compounds.

VARIABILITY FACTORS OF ESSENTIAL OILS

i. Occurrence of Chemotypes

ii. Influence of the vegetative cycle

iii. Influence of environmental factors

iv. 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 METHODBecause 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 - GingerGEOGRAPHICAL 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

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 & ACTIONSACTIONS 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 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.

MACROSCOPICAL FEATURES 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

MICROSCOPICAL FEATURES

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 SOURCESCultivated in Sri Lanka, South India, Seychelles, Madagascar, Martinique, Cayenne, Jamaica & Brazil.

CULTIVATION, COLLECTION & PREPARATION

Grown from seedCut 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.

MACROSCOPICAL FEATURESNormally 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: 10-40mm.

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

MICROSCOPICAL FEATURES 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

CONSTITUENTS

Should contain at least 2.5% volatile oil

Vitamin C

Hesperidin (Flavonoid)

Mucilage

Calcium Oxalate

USES

Flavouring purposes

LEMON OILS - Oleum limonisDefinition: 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 Oilsii. Machine ProcessesQuality 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

iii. Distilled OilsAlthough 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 40-50 %.

It is equal in flavouring to 10-15 times its volume of lemon oil

BUCHU – Agathosma betulina

Agathosma betulina – CONSTITUENS & USES

CONSTITUENTSVolatile oils• Pulegone• Menthone & isomenthone• limoneneDiosminMucilageResinCalcium oxalatesBuchu camphor – Responsible for the diuretic action

USES/ACTIONSDiureticUrinary Tract Anti-Septic – Used for UTI’s

NUTMEG & NUTMEG OIL

Definition: Nutmeg is the dried kernel of the seed of Myristica fragrans (Myristicaceae).

Geographical SourcesIndigenous 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.

MACROSCOPICAL FEATURES

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.

MICROSCOPICAL FEATURES

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 OILNutmeg oil is distilled from the

kernels of Myristica fragrans.

CONSTITUENTSPineneSabineneCampheneDipenteneSafroleEugenol & eugenol derivativesMyristicin – a benzene: toxic to

humans (large does of nutmeg or nutmeg oil may cause convulsions).

MACECommon mace or

Banda mace consists of the dried arillus or arillode of M. fragrans.

Description: bright red colour & lacks in aroma.

MACE – CONSTITUENTS & USES

CONSTITUENTS

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 CLOVECloves 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 & PREPARATIONThe 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.

MACROSCOPICAL FEATURES

Cloves are 10-17.5 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

MICROSCOPICAL FEATURES

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

TanninsTriterpene acids & estersGlycosides

USES OF CLOVE

Stimulant aromatic

Spice

For the preparation of volatile oil

Sesquiterpenes: potential anti-carcinogenic compounds

CLOVE OILOil 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 SOURCESPortugal, 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

CHARACTERISTICSColourless or pale yellow liquidAromatic & 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

- All due to anethole (and fenchone)

USESFlatulenceDyspepsiaChronic 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

MACROSCOPICAL FEATURES

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

MICROSCOPICAL FEATURES

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• Carveole8-20 % Fixed oilsProteinsCalcium oxalatesColouring matterResin

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.

MACROSCOPICAL FEATURESAnnual 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.

MICROSCOPICAL FEATURES

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 & estersFlavonoidsCoumarinsPhenolic acidsHigh 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

MACROSCOPICAL FEATURESAll 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, 15-32 & menthone and 4.5-10 % menthyl acetate.

Oleum Menthae - CONSTITUENTS

MentholMenthone & isomenthoneMenthyl acetateLimoneneCineoleMenthofuranPulegoneCineole

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