Page 73 - Phytochemistry 2 (06-PG 605)

Pharmacology and uses
Atropine, hyoscyamine and scopolamine are cholinergic

blocking agents. They decrease gastric and salivary secretion,
increase heart rate (by depression of the vagus nerve), depress
the motility of the gastrointestinal tract and act as antispasmodic
on various smooth muscles (ureter, bladder and biliary duct). In
addition, they stimulate the respiratory center. They are used
externally as mydriatic drugs.

The action of scopolamine differs from that of hyoscyamine
and atropine in that there is no central nervous system stimulation,
but rather a narcotic or sedative effect predominates.

Scopolamine HBr is used as antiemetic; and 0.025% solution of
the benzoate ester of hyoscine is used for hyperhydrosis.

Coca alkaloids

Coca leaves contain two types of alkaloids:
1- Tropane alkaloids: cocaine, cinnamyl cocaine & truxillines

and tropacocaine.
2- Pyrrolidine alkaloids: hygrine and cuscohygrine.
Tropane coca alkaloids

Tropane coca alkaloids are obtained from the leaves and
shrubs of Erythroxylon coca. Coca leaves contain about 0.7 to 2%
of total alkaloids of which cocaine, cinnamyl cocaine and α-
truxilline are the most important. Coca alkaloids are di-esters of
ecgonine base.

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