Extraction and Separation of Natural Products - Natural Products Chemistry: Sources, Separations, and Structures - page 18

O

O O

(a) (b)

FIGURE 2.6 (a) Linalool and (b) linalyl acetate monoterpenes give rise to the distinctive odor

of lavender.

EXAMPLE 2.1: ESSENTIAL OILS—HYDROSOL FROM LAVENDER

Lavandula angustifolia is the most widely cultivated species. It is a plant native
to the western Mediterranean, but widely cultivated all over the world, includ-
ing the British Isles, France, United States, Argentina, and Japan. Distillation of
the lavender buds, spikes, and flower tips can produce the essential oil. During
steam distillation of essential oils, large quantities of aqueous distillate are pro-
duced. The resulting mixture of essential oils, known as hydrosol, is widely
used in aromatherapy and massage therapy. The distinctive odors of lavender
are due to the key monoterpenes: linalool and linalyl acetate (Figure 2.6).

EXAMPLE 2.2: CAFFEINE AND THE DECAFFEINATION PROCESS OF COFFEE

Coffee comes from the Coffea genus of flowering plants. Although it is not respon-
sible for the well-known coffee aroma, caffeine, present in the seeds, can protect
the seeds themselves due to its toxicity to herbivores. One of the most popular
species of the genus whose seeds contains caffeine is Coffea arabica (Figure 2.7).

The chemical formula of caffeine is C 8 H 10 N 4 O 2 (Figure 2.8). It is a weakly basic,
white colorless powder in its anhydrous state. In water at room temperature its solu-
bility is 2 g/100 mL, increasing to 66 g/100 mL when mixed with boiling water.

HISTORICAL NOTE

The first successful decaffeination was achieved in 1820, when the German chem-
ist Runge analyzed the constituents of coffee to discover the possible cause of
drinking coffee and insomnia. A more significant breakthrough occurred in 1903
by Ludwig Roselius. He pretreated the coffee beans with steam and eventually this
discovery became the basis for commercial production of decaffeinated coffee in
the early 20th century.