Page 69 - Phytochemistry 2 (06-PG 605)

Properties
It is the major alkaloid in Duboisia and scopolia species and

Datura metel. It is laevorotatory. It occurs as syrupy liquid, that is
soluble in water, very soluble in ethanol, chloroform and ether.
Enzymatic hydrolysis with lipase yields L tropic acid and scopine;
while acid or alkali hydrolysis yield scopoline base and tropic acid.
Scopolamine HBr is the most commonly used salt for medicinal
purposes.
Uses

Hyoscine HBr is commonly used in medicine as sedative,
mydriatic, antiemetic, for the treatment of hyperhydrosis and as
CNS depressant.

Identification of tropane alkaloid
1- Vitali-Morine's test https://youtu.be/a8TkwYyWE14
The alkaloid is treated with fuming nitric acid. The mixture is

evaporated to dryness on a water bath. The yellow residue is
cooled then treated with few drops of 3 % alcoholic KOH solution,
it gives a bright purple or violet colour. It is the most useful,
although it is non specific test. This test is sensitive and can be
used for colourimetric estimation of tropane alkaloids.
2- Gerrard's reaction

When few mg of the alkaloids are treated with 2% HgCl2 in
50% ethanol, a red colour is formed in case of hyoscyamine and a
white precipitate in case of hyoscine.
3- Test with p-dimethylaminobenzaldehyde reagent (PDMAB).
The alkaloid is treated with PDMAB /H2SO4. On warming in a
water bath a red colour is produced that turns to cherry red colour
on cooling.

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