Page 193 - PG 504-theoretical notes-phyto-1-2024-2025..

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

COOCH 3 COOCH 3

Ogluc.Xyl. OH
Gualtherase
H O Glucose
2
Xylose
Gualtherin (Monotropin)
from Gualtheria procumbens

Determination of Volatile Oils in Plant Materials

For estimation of the volatile oil content in raw plant materials, Clevenger's cohobation
apparatus is used depending on whether the oil is lighter or heavier than water.

A known weight of the plant materials is used in one of the shown apparatus. The round-
bottom flask containing the plant material and water (enough to cover and immerse the
plant material).

Distillation should be continued for 6-8 hours.

The amount of the oil is read from the graduated side tube at the end of the experiment and the %
volume/ weight (v/w) is calculated.
Quantitative determination of the Volatile oil

Oil heaver than water Oil lighter than water

Clevenger's cohobation apparatu

Chemistry of Essential oils

• Volatile oils are complex mixtures of different groups of chemical compounds.

• They are generally mixtures of hydrocarbons and related oxygenated compounds.

• Volatile oil may contain one major component as clove oil [contain not less than 85%
eugenol] or entirely composed of one constituent [as bitter almond oil (benzaldehyde),
oil of winter green (methyl salicylate), mustard oil (allyl isothiocyanate) ~ 100%].

• The building units of all terpenoids are the isoprene units which is C5H8.

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