Sugar and Fat and All of That - Natural Products Chemistry: Sources, Separations, and Structures - page 52

HO OH

OH

FIGURE 5.11 Chemical structure of glycerol.

5.14 TRIGLYCERIDES
In the body, fatty acids are stored in the form of a triglyceride and found in adipose
tissue. Once fatty acids are converted into the triglyceride they can enter the blood-
stream. These lipid triglycerides can be in the form of fat (solid) or oil (liquid). In
general, they are composed of 3 parts fatty acids + 1 part glycerol.

5.15 GLYCOL S
Glycerol has the chemical formula C 3 H 3 (OH) 3 (Figure 5.11).

5.16 FATTY ACIDS
The fatty acids are a major contributor to lipid-like molecules and their chemistry.
The naturally occurring fatty acids may be either saturated or unsaturated; the for-
mer having higher melting points than the latter of corresponding size. The fatty
acids are precursors to numerous compounds, and examples of various structures
are illustrated in Figure 5.12.
The essential fatty acids (Figure 5.13) are important to overall human health, yet
they cannot be synthesized by the body, therefore they are obtained from the diet.
Two important fatty acids, namely linoleic and linolenic, are designated “essential,”
because their absence in the human diet has been associated with health problems,
such as scaly skin, stunted growth, and increased dehydration. A lack of either of
these two fatty acids can lead to ill health and causes deficiency symptoms.
Linoleic acid is an integral part of the cell component and is used to manufacture
signaling molecules in the body. Linoleic acid is an omega-6 fatty acid. It consists of
an 18-carbon chain, a carboxylic acid group, and two cis double bonds at positions
C9 and C12.
Linolenic acid is a component of cell membranes and used by the body to make sub-
stances called eicosanoids, which regulate inflammation. Linolenic acid is an omega-3
fatty acid. It consists also of an 18-carbon chain and a carboxylic acid but possesses
three cis double bonds. Linolenic acid exists in both the alpha and gamma forms sig-
nifying the difference in the location along the chain of the three double bonds.

5.17 SOURCES OF OMEGA OILS
The term omega identifies the family of the fatty acids that are generally found in
salmon, mackerel, and krill. The basic omega-3 fatty acid is alpha-linolenic acid
with the chemical formula C 18 H 30 O 2 (Figure 5.14) with three double bonds. In this