Euphorics - Natural Products Chemistry: Sources, Separations, and Structures - page 83

8 Euphorics

Plants that generate a euphoric effect in humans and possess psychoactivity have
played an important role in the culture of mankind and with indigenous and ethnic
minorities. There are prescription drugs that are known for their euphoric effects.
Examples include morphine and codeine derived from opium. In some countries
there are illicit drugs: cocaine from the coca leaf and marijuana from cannabis, all
described further in this chapter. There are also euphoric compounds that have a
degree of social acceptance, such as nicotine (Figure 1.4) in tobacco and caffeine
(Figure 2.7) in tea and coffee.

8.1 MORPHINE
Morphine is a natural alkaloid (Figure 8.1) produced in the poppy plant Papaver
somniferum (Figure 8.2). This plant usually grows in arid climates, typically in regions
of the Far East, such as Iran and Afghanistan. When ripe for harvesting the poppy
produces a white sticky latex called opium. Farmers harvest opium 2 weeks after the
petals fall from the bud. They make two or three incisions into the pod's skin using a
sharp blade, which allows the latex to ooze out slowly to harden over a 24-hour period
on the outside of the pod, at which time it is then collected. This latex, or opium, is a
complex mixture containing at least 50 different alkaloids. The most abundant alkaloid
is morphine, which makes up 8% to 17% of the dry weight of opium.
Although it has been used for centuries, the chemical structure of morphine was
only determined in 1925. The vast majority of morphine continues to be harvested
from the opium poppy, however, there are at least three ways of synthesizing mor-
phine from simple starting materials such as coal tar and petroleum distillates.

8.2 ISOLATION OF MORPHINE
Morphine and related alkaloids can be purified from opium resin and crude extracts
by extraction in the following manner: first, soaking the resin with diluted sulfuric
acid, which releases the alkaloids into solution. The alkaloids are then precipitated

HO

O H

H

N

CH 3

HO

FIGURE 8.1 Chemical structure of the alkaloid morphine.

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