Page 9 - phytochemistry general program

Generally, the levo rotatory l (-) isomers more active pharmacologically than
dextro rotatory d (+) isomers of the same alkaloid.

Exceptions:
d(+) pilocarpine, d(+) tubocurarine and d(+) quinidine are medically used. .1

Another exception is the optically inactive papaverine (has therapeutic .2
effect).

Sometimes, the difference in the opt. activity of the same chemical structure .3
cause change in therapeutic uses .e.g.

l (-) Quinine is antimalarial, while

d (+) Quinidine is used in treatment of auricular fibrillation.

Solubility:
As a general rule:
The free alkaloid bases are .1
soluble in organic solvents. .2
sparingly soluble in H2O .3

Alkaloid salts are .1
soluble in H2O .1
.2
sparingly soluble in organic solvents. .1
Alcohol, dissolve both (bases & salts).

Exceptions:

a) H2O-soluble alk. bases

Caffeine, and still .1
.2
Colchicine Soluble in organic solvents .3
.4
Ephedrine

Pilocarpine

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