Page 96 - phytochemistry general program

Xanthine alkaloids are very weak bases, forming salts with only very strong
acids which can be easily hydrolyzed in water. They do not give precipitate with

Mayer’s reagent. They all give Murexide positive test.

Caffeine .1

The alkaloid Caffeine occurs in seeds of Coffee ( Coffea arabica, family
Sterculiaceae) (1-2%), in the seeds of different species of Cola family

Sterculiaceae, (2-3%); in the leaves of Tea (Camelia sinensis, family Theaceae)
(2-5%); and in Guarana seeds Paulinia cupana (Sapindaceae) (2.5-5%).

Properties

Caffeine occurs as a white powder or white glistening needles. It is odorless
sublimable (on heating) without decomposition. Caffeine is soluble in water (1:50),
hot water (1:6), in acetone (1:50), in benzene (1:100) and more soluble in
sparingly soluble in ether. The stability of caffeine in water in increased by addition

.of organic acids or their salts e.g. citric acid, sodium benzoate and salicylate

Uses

Caffeine is a central nervous system (CNS) stimulant, having the effect of
temporarily warding off drowsiness and restoring alertness.

Caffeine is the world's most widely consumed (psychoactive) substance, Most
commonly consumed as beverages, such as coffee, tea, soft drinks and energy

drinks that enjoy great popularity worldwide.

Caffeine has a lipolytic effect on fatty cells, able to break down lipids and
release fatty acids. Also used for skin firming and tightening. It is often
incorporated into body product formulations targeting cellulite and slimming, as

well as in eye creams that claim to reduce puffiness.

It is the most commonly consumed by humans in infusions extracted from
the seeds of the coffee plant and the leaves of the tea, as well as from various
foods and drinks containing products derived from the kola nut and guarana

seeds.

Isolation of caffeine from tea leaves

The powdered tea leaves, is extracted by boiling (refluxing) with water. The

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