In The Name of ALLAH , The Most Beneficent and Merciful
Muhammad Najiur Rahman Presented By
My Presentation Based on: Different Types of Volatile Oil and Their Medicinal Value
Welcome To Our Presentation
Contents 1.Volatile oils 2.Significance 3.Role in plants 4.Properties 5.Classification 6. Chemical constituents 7. Methods of obtaining 8. Volatile oil Vs. Fixed oil 9.Medicinal values 10. How it use
They evaporate when exposed to the air at ordinary temperatures so they are called volatile oils, ethereal oils or essential oils. They are called essential oil because volatile oil represent the essences of plants. Volatile oils
Significance of volatile oil As spices and condiments Flavoring agents As carminative Manufacture of perfumes, soaps, cosmetics etc.
Role of volatile oils in plants Due to disagreeable taste and odor, they protect the plants from grazing animals In flowers, they attract the insects for pollination.
Properties of volatile oils Characteristic odors High refractive index Optically active Immiscible with water Soluble in ethers, alcohol and most organic solvents
1. H ydrocarbon volatile oils It has been observed that terpene hydrocarbons usually occur in most of the volatile oils obtained from natural sources. They may be further classified into three categories, namely: ( a ) Unsaturated acyclic hydrocarbons, ( b ) Aromatic hydrocarbons, and ( c ) Alicyclic hydrocarbons. Ex: Turpentine – pinene , carene , limonene
2. Alcoholic volatile oils A good number of alcohols occur abundantly in a plethora of volatile oils, which may be judiciously classified into the following heads, namely: ( a ) Acyclic (aliphatic) alcohols, ( b ) Monocyclic (aromatic) alcohols, ( c ) Alicyclic ( terpene and sesquiterpene ) alcohols. Ex: 1. Peppermint- Menthol 2. Cardamom- Borneol 3. Coriander- Coriandrol (Linalool) 4. Rose- Nerol 5. Sandalwood- Santola
3 . Aldehydic volatile oils Aldehydes provide a soapy-waxy-lemony-floral effect to the formula and are used to classify a fragrance as " aldehydic ". Ex: 1. Cinnamon - Cinnamic aldehyde 2. Lemon peel - Citral 3. Orange peel - Citral 4. Citronella - Citronellal 5. Lemon grass - Citronellal
4 . Ketonic volatile oils The ketones that invariably occur in volatile oils may be classified in the following two categories, namely: ( i ) Aliphatic ketones , and ( ii ) Aromatic Ketones . Ex: Caraway- Carvone , Spearmint- Carvone , Vetiver - Vetivone , Fennel- Fenchone
5 . Phenolic volatile oils The important drugs containing phenol volatile oils are, namely: Clove oil, Myrcia oil (Bay oil), Organum oil, Pinetar , Thyme etc. In fact, they essentially owe their value in the pharmaceutical domain almost exclusively by virtue of their antiseptic and germicidal properties of their phenolic constituents . A good many of them are employed as popular flavouring agents. The phenols are classified into the following categories, namely: ( i ) Monohydric phenols and ( ii ) Dihydric phenols. Ex: Clove – Eugenol , Ajwon – Thymol
6 . Phenolic ether volatile oils Phenolic ether occurs in volatile oils such as anethol from anise and fennel, Safrole from sassafras etc. Ex: Anise , Fennel – Anethol , Nutmeg - Myristicin
7 . Oxide volatile oils It contains colourless or pale yellow oil which is about 6%, having an aromatic odour , spicy cooling taste, containing 70% of cineole C10H18O, d- pinene and other terpenes , resins, a bitter principle and tannin, eucalyptic acid, Ca-oxalate etc. Ex: Eucalyptus – Cinole (eucalyptol)
8 . Ester volatile oils A wide variety of ester occurs in volatile oils. The most common are the acetates of terpineol borneol and geranial. Other examples of esters in volatile oils are allyl isothiocyanate in mustard oil and methyl salicylate in wintergreen oil. Ex: Gaultheria(Wintergreen) – Methyl salicylate
Chemistry Chemical constituents of volatile oil may be classified into two groups. Terpenes Phenylpropanoids
a. Terpenes Natural products whose structures may be divided into isoprene units. These units arise from acetate via mevalonic acid. These are branched chain 5 carbon units containing 2 unsaturated bonds. Made up of head to tail condensation of isoprene units. If 1 isoprene unit present= hemiterpene (C5H8) 2 isoprene unit present= monoterpenes (C10H16) 3 isoprene unit present= sesquiterpene (C15H24) 4 isoprene unit present= diterpene (C20H32) 6 isoprene unit present= triterpene (C25H48) Majority of the terpenes are monoterpenes in volatile oils.
b. Phenylpropanoids They are formed via shikimic acid phenylpropanoid route. These compounds contain phenyl ring with an attached propane side chain. Many of the Phenylpropanoids found in volatile oils are phenols or phenol ethers.
Methods of obtaining volatile oils The method of obtaining volatile oils depends upon the condition of plant materials. Oil production can be divided into three major ways Distillation Solvent extraction Mechanical expression Specialized methods are: Ecuelle Method Enfleurage Destructive distillation
Difference between volatile oil and fixed oil Evaporate from source when exposed to room temperature. Color less liquid, or crystalline or amorphous solid. Do not form permanent stains on paper. Do not rancidify . Having distinct odor. Can be distilled from natural sources. On exposure to air and light, they oxidize and resins are formed. Remain fixed on the source when exposed to room temperature. Some of these oils possess colors i.e. castor oil, shark liver oil. Form permanent stain on paper. Rancidified on exposure to air. May or may not possess odor. Can not be distilled. On exposure to air or light, it becomes rancid developing a disagreeable odor.
Can not be saponified . Mixture of mono sesquiterpenes . Immiscible in water but soluble in alcohol. Can be saponified . They are esters of glycerol with long fatty acid chain. Soluble in water, sparingly soluble in cold alcohol. Difference between volatile oil and fixed oil
Medicinal Values of Volatile Oil
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