Page 91 - phytochemistry general program
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The bark contains about 6% total alkaloids, the main of which is Yohimbine.
N
N
H
Yohimbine
H3COOC
OH
Properties
Yohimbine occurs as orthorhombic needles from dilute ethanol, m.p. 234˚C.
It is slightly soluble in water, soluble in ethanol, chloroform and hot benzene,
sparingly soluble in ether.
Tests for identification
On treatment of yohimbine with concentrated H2SO4 and crystals of K2Cr2O7, .1
violet streaks are obtained that turns blue then green (c.f. strychnine).
Yohimbine gives with Mandalin's reagent a blue color that turns to green (c.f. .2
strychnine that gives a violet color which changes to red).
Uses
Yohimbine is mainly used as an aphrodisiac drug.
Rauwolfia alkaloids .3
Occurrence
Rauwolfia roots (Rauwolfia serpentina, family Apocynaceae) contain several
alkaloids, the most important of which is reserpine.
Rauwolfia alkaloids are subclassified as follows:
The weakly basic tertiary colorless alkaloids e.g. reserpine, deserpidine and .1
recinamine. .2
.3
The intermediately basic tertiary colorless alkaloids e.g. ajmaline and
rauwolfine.
The strongly basic quaternary yellow alkaloids e.g. serpentine and serpentinine.
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