Page 221 - PG 504-theoretical notes-phyto-1-2024-2025..

Clinical pharmacy PharmD program Third level Phytochemistry-1 (PG-504)

V- Esters in volatile oils

• Esters are widely distributed in many essential oils. The most common is the acetate.
However oil of winter green is composed mainly of methyl salicylate.
• Esters saponify with alkalis to give the corresponding alcohol and the acid salt, and this
is the basis for their quantization.

• The best methods for detection and isolation of esters seems to be the GC/MS and HPLC.

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• Esters pure isolates chemical structures is confirmed by H and C-NMR and mass
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spectrometery.

Esters isolated from the volatile oil can be classified according to the acyl radical into:
• a) Esters of aliphatic acid

• b) Esters of aromatic acids

• c) Esters containing nitrogen

a) Aliphatic b) Aromatic

e.g. Geranyl e.g. Linalyl e.g. Benzyl benzoate e.g. Methyl
acetate acetate salicylate

Occurence: In lavender In balsams In oil of
wintergreen
In oil of
citronella

Isolation: By cooling By enzymatic
hydrolysis
by distillation under vacuum to
avoid hydrolysis

Uses: Main use scabicide Rubifacient,
(Benzanil Cream). antiseptic &
In perfume, cosmetic & soap antirheumatic
industry As diluent & fixative
in perfumes,

c) Esters Containing Nitrogen

e.g. Methyl anthranilate

• Occurrence: in oil of orange, lemon, Jasmine
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