Page 97 - phytochemistry general program

extract is filtered, boiled and treated with lead acetate solution (precipitation of
tannin) and filtered. The excess lead in the filtrate is removed by addition of
sodium hydrogen phosphate and filtered. The filtrate is concentrated and caffeine

is extracted with chloroform.

Theobromine .2

Theobromine occurs naturally in seeds of Theobroma cocao (Sterculiaceae).

Properties

sparingly soluble in water (1:1800), ,Theobromine is white crystalline powder
slightly soluble in alc. (1:400), insoluble in chloroform, benzene and ether.
Theobromine becomes readily soluble in water when mixed with salts of organic
acids e.g. calcium salicylates, sodium acetate or sodium salicylate. Theobromine
is an amphoteric alkaloid forming salts with alkali and acids. It is sublimable at
290OC without decomposition. Theobromine forms insoluble salt with silver nitrate
which is gelatinous in presence of ammonia solution. Upon warming with
ammonia, gelatinous precipitate dissolves and by boiling for sometimes, granular
insoluble precipitate is formed. This reaction can be used for separation of

theobromine from caffeine.

Uses

Theobromine is diuretic especially in cardiac oedema.

Theophylline .3

theophylline in tea It occurs in small quantities in tea leaves. The amount of
leaves is too small to be of commercial importance and consequently, it is made

.synthetically

Properties

Theophylline occurs as white, odorless crystalline powder, sparingly soluble
in water (1:120), soluble in alcohol (1:80), very sparingly soluble in ether and
chloroform and insoluble in benzene. It is easily soluble in ammonia. It forms
insoluble salts with silver nitrate. The formation of silver salt is usually used in the

isolation of theophylline from tea leaves.

Uses and Pharmacological actions of theophylline involve

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