Page 32 - Pharmd general phytochemistry I-Final2024_LEUCTERS
P. 32
Menthol and thymol separation:
Both are dissolved in chloroform, then alkalinization
with aqueous fixed alkali (NaOH, KOH)
Aqeous layer Chloroform layer
Contains thymol Contains menthol
as water soluble phenate
(because thymol is a
phenolic compound)
Color tests:
◦ Menthol + conc. H2SO4 + vanillin/H2SO4 → orange yellow color.
◦ Menthol + conc. H2SO4 + conc. HNO3 → NO COLOR (Thymol gives
a green color).
Reactions of menthol:
Uses:
- Menthol is a local antipruritic.
- It has been used on the skin or mucous membranes as a counterirritant
and antiseptic.
- Menthol is chiefly used to relieve symptoms of bronchitis, sinusitis as it
is a good decongestant and expectorant.
30
