Page 237 - PG 504-theoretical notes-phyto-1-2024-2025..

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

Preparation;

• The powdered fruits are defatted by means of petroleum ether.
• The powder is then extracted by boiling with alcohol or with water, and then filtered.

• The filtrate is treated with lead acetate solution, filtered and the excess lead is removed by
hydrogen sulfide and the filtered.

• The filtrate is concentrated and left in a refrigerator for crystallization.

• Picrotoxin is purified by active charcoal and crystallized from boiling water or alcohol.
Chemical test:

1) Picrotoxin dissolves in conc. sulfuric acid to give yellow color which gradually changes to reddish-
brown.

2) To a mixture of about 0.2 g of potassium nitrate and 4 drops of conc. sulfuric acid in an evaporating

dish add few crystals of picrotoxin, followed with sodium hydroxide solution drop wise until it is
in excess. Picrotoxin particles acquire a red color, gradually fading.
3) Add one drop of conc. sulfuric acid to few crystals of picrotoxin (just moisten), then add one drop

of alcoholic anisaldehyde solution; permanent blue color is produced.

4) Add 2 ml of Fehling’s reagent to few crystals of picrotoxin, dilute with 10 ml of water, a red
precipitate is slowly formed in the cold, but rapidly on heating.

5) Picrotoxin gives a green color on boiling with vanillin/hydrochloric acid solution.
6) Picrotoxin reduces ammoniacal silver nitrate solution (Tollon’s reagent).

Structure:

• Picrotoxin consists of equimolecular proportions of picrotoxinin and picrotin. Both are highly
oxygenated sesquiterpene derivatives.
O O
O O
O O

O CO OH O CO OH

OH

Picrotoxinin Picrotin

Uses:

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