Natural Products Sources - Natural Products Chemistry: Sources, Separations, and Structures - page 2

Pyruvid Acid (3C)

2H CO 2

Acetyl CoA (2C)

Citric Acid (6C)

4C compound

CO 2

2H

2H

Krebs
Cycle

5C compound

4C compound

4C compound

CO 2

2H

2H

NAD + 2H NADH 2

FIGURE 1.1 The Krebs cycle indicating that metabolic processes and enzymatic reactions
begin from simple building blocks.

O O

O

O

FIGURE 1.2 The active ingredient in willow bark is salicin, which is converted in the body
into salicylic acid. Salicylic acid is more commonly known as aspirin.