Page 62 - Phytochemistry 2 (06-PG 605)

Theobromine is white crystalline powder ,sparingly soluble in
water (1:1800), 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

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

Theophylline occurs as white, odourless 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.

Pharmacological actions of theophylline involve;
- relaxing bronchial smooth muscle.

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