bio synthesis of volatile oils

8/3/2019 Bio Synthesis of Volatile Oils

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Biosynthesis of

Volatile oils

Under supervision of:

Dr : Amina Hanem Abo DoniaDr :Hala Mostafa Abd ElghanyDr : Hatem Mohamed Miky


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VOLATILE OILS

Volatile or essential oils, as their

name implies, are volatile in steam. They differ entirely in both chemical

and physical properties from fixed

oils. They are secreted in oil cells, in

secretion ducts or cavities or in

glandular hairs.


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Production and uses of volatile oils

The total annual production of volatile oils

is estimated to be in the region of 45,000tones, worth approximately US$700million.

There are about 100 commercially

valuable volatileoils directly derived fromplants.

Volatile oils are used for their therapeuticaction, for flavoring(e.g. oil of lemon), in

perfumery(e.g. oil of rose) or as startingmaterials for the synthesis of othercompounds(e.g. oil of turpentine).


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For therapeutic purposes they are administered

as inhalations(e.g. eucalyptus oil), orally(e.g.peppermint oil), as gargles and mouthwashes(e.g. thymol) and transdermally(many essentialoils including those of lavender, rosemary andbergamot are employed in the practice of

aromatherapy).

Those oils with a high phenol content, e.g. cloveand thyme have antiseptic properties, whereas

others are used as carminatives. Oils showingantispasmodic activity, and much used in popularmedicine.


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Composition of volatile oils

Volatile oils are generally mixtures of

hydrocarbons and oxygenatedcompounds derived from thesehydrocarbons.

The odour and taste of volatile oils ismainly determined by these oxygenatedconstituents, which are to some extent

soluble in water but more soluble inalcohol.


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Practically all volatile oils consist of chemicalmixtures that are often quite complex; they varywidely in chemical composition.

Almost any type of organic compound may befound in volatile oils (hydrocarbons, alcohols,ketones, aldehydes, ethers, oxides, esters, and

others). usually volatile oils are classifiedaccording to the type of organic compounds.

It is not uncommon for a volatile oil to contain

over 200 components, and often the traceconstituents are essential to the odor and flavor.The absence of even one component maychange the aroma.


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Essential oils are products ofa secondary metabolism of plants,

and are composed of :1- Fragrant volatile materials consistingof complex mixtures of:

mono- and sequi-terpenes,hydrocarbons, and oxygenatedmaterials biogenically derived from

them (i.e. terpenoids)


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2- Phenyl propanoids from the Shikimic

acid pathways, and theirbiotransformation products (i.e.aromatics )3- Other compounds from themetabolism of fatty acids and aminoacids

4- A large number of other types ofchemical compounds, including

nitrogen and sulphur


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em ca cons uen s ovolatile oils

Chemical constituents of volatile oils maybe divided into 2 broad classes, basedon their biosynthetic origin:

1- Terpene derivativesformed via theacetate-mevalonic acid pathway.

2- Aromatic compoundsformed via theshikimic acid-phenylpropanoid route.


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Terpene pathway

1- Terpene derivatives

formed via the acetate-mevalonic

acid pathway.


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Terpene derivatives

CH3

OH

H3C CH3

Menthol(peppermint oil)

CH3

O

H3C CH2

Carvone

(caraway oil)

CH3

H3C CH3

OH

Thymol(thyme oil)


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Photosynthesis

Is the process by which, with the

help of sunlight, plants canproduce carbohydrates in theirchlorophyll-containing cells using

water (from the soil) and carbondioxide (from the air )light

6CO2+6H2O C6H12O6+ 6O2


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The product of these reactions,

glucose, is then split throughfurther reactions, from which anew compound - pyruvic acid

(C3H4O3) is born.Pyruvic acid is further broken down

to acetic acid (C2H4O2)


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The path leading from

carbohydrates to terpenesinvolved isoprene as a biogenicprecursor.


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Modern theories suggest that a

compound called mavelonic acidmight be the root source of manycompounds in essential oils.

And here is a short summary of how

it happens


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Acetic acid is converted through a

series of condensation andreduction reactions to mavelonicacid, which in turn - via series ofredoc reactions - leads to

monoterpenes.

The terpene framework is then

rearranged, oxidised, reduced,hydrated etc., to produce a rangeof terpenoid products


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Mavelonic acid

IPP (isopentenyl pyrophosphate) +

DMAPP

(3,3-dimethylallylpyrophosphate)

GPP (geranyl pyrophosphate)monoterpenes


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Occurs inExampleTerpenoid class

Ylang-ylang oils

Cananga odorata

subsp. genuina

Prenol (syn. 3-

methyl-2-butenol),

prenyl esters

Hemiterpenoid

C5

Citrus oils (Citrus

spp.)

LimoneneMonoterpenoid

C10

Clove oil Syzigium

aromaticum

beta-CaryophylleneSesquiterpenoid

C15

Clary sage absolute

Salvia sclarea

SclareolDiterpenoid

C20

Certain

fungi

Ophiobolin ASesterterpenoid

C25

Jasmin absolute, wax

Jasminum

grandiflorum

IsophytolTriterpenoid

C30

Green plant tissuesbeta-CaroteneCarotenoid

C40


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The Mevalonate IndependentPathway

Pyruvate

Hydroxy ethyl thiamine pyrophosphate +(3-glycerylaldehyde-3-phoshate)

1-deoxy-D-xylulose 5-phosphate

IPP.


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Biosynthesis and chemical composition

Chemical constituents of volatile oils

may be divided into 2 broad classes,based on their biosynthetic origin:

1. Terpene derivativesformed via the

acetate-mevalonic acid pathway.2. Aromatic compoundsformed via the

shikimic acid-phenylpropanoid route.

Shiki i A id P h


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Shikimic Acid Pathway

Shikimic acid is formed from glucose in

plants, and is the biogenic precursorof the amino acids L-phenylalanine,L-tyrosine and L-typtophan.


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Pathways from shikimic acidgenerate

1- anthranilates e.g. in mandarin oilCitrus reticulata

2- Cinnamates

e.g in peru balsam oil

and other phenylpropanoids,and from this point on to othermetabolites such as lignans &

flavononoids.


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3-carbon chain attached to a benzene

ring are formed fromtrans or (E)-cinnamic acid via the

elimination of ammonia from L-phenylalanine.

Common phenylpropanoids inessential oils include methyl

chavicol, methyl eugenol, eugenol,methyl cinnamate, vanillin &anethole.


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An investigation of accumulation of

phenylpropenes in the two types ofglandular trichomes

1-(peltate & capitate) in twochemotypes of Sweet Basil

2- (eugenol & methyl chavicol) oilleaves

A ti d


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Aromatic compounds

OH

OCH3

Eugenol

(clove oil)

OCH3

CH3

Anethole

(anise oils)

CHO

Cinnamaldehyde

(cinnamon oil)

CH2


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Refrences

PDR hand books

www Faculty ksu eupharmacognosy


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Thank You

By :

Doaa Mohamed shoshan

THANK YOU

By:Doaa Mohamed shoshan

bio synthesis of volatile oils

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