Isolation and separation of TerpenoidsPrepared byDr. N.GOPINATHANASSISTANT PROFESSORDEPARTMENT OF PHARMACEUTICAL CHEMISTRYFACULTY OF PHARMACYSRI RAMACHANDRA UNIVERSITYCHENNAI-116TAMILNADUINDIA

• Essential oil contain a number of terpenoids belonging to mono and sesquiterpenoid group.

• Isolation of individual terpenoid can be achieved by chemical as well as physical method

Chemical method

• Certain chemical methods have been applied for the separation of terpenoids.

• In 1877, tilden discovered that whenever terpenoid hydrocarbon are treated with nitrosyl chloride in chloroform [ Tilden’s reagent].

• Crystalline adducts having sharp melting point are obtained

• The adducts were separated and decomposed into their corresponding hydrocarbons.

Terpenoid- alcohol• It is separated by their reaction with

Phthalic anhydride to form diesters when the primary alcohol react readily, secondary alcohol less readily and tertiary do not react.

• The diesters are extracted with NaHCO3 and then decomposed by alkali to the parent terpenoid alcohol

• Terpenoid aldehydes and ketones were seperated by reaction with common carbonyl reagent such asNaHCO3, 2,4 dinitro penyl hydrazine, phenyl hydrazine reagent.

Physical method

• Fractional distillation method• The various terpenoids present in essential oil

are separated by fractional distillation method.

• The terpenoid hydrocarbon distill over first followed by oxygenated derivative.

• Distillation of the residue under reduced pressure yield sesquiterpenoids and these are separated by fractional distillation.

• Fractional distillation is to be carried out under reduced pressure in the presence of an inert gas.

• These conditions are essential because many terpenes are sensitive to heat and atmospheric oxygen.

Chromatography • In adsorption chromatography, the

essential oil is made to flow through a particular adsorbent

• Different types of terpenoid are adsorbed at different places on the adsorbent to form different chromatogram

• Then various chromatograms are eluted by different solvent system to get different elute.

• Alumina and silica gel are used as adsorbent.

• Vapor phase partition , counter current and gas chromatography have been used.

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