Organic Chemistry: Concepts and Applications - Headley Allan D. 2020

Synthetic Polymers and Biopolymers
20.22 Structure and Properties of Steroids, Prostaglandins, and Terpenes

Steroids are compounds that have the basic structure shown below.

Figure 20.5 Lecithin, a phospholipids, which is used for the treatment of various memory disorders.

There are three six-member rings that are fused and a five-member ring. These rings are often described as A, B, C, and D rings. For example, steroids have the A, B, C, and D rings and all have specific biological functions.

Prostaglandins are compounds that have a wide range of hormone-like effects on the body. For example, prostaglandins are involved in the contraction and relaxation of smooth muscle, the dilation and constriction of blood vessels, the control of blood pressure, and the modulation of inflammation. Thromboxane is a type of prostaglandin that stimulates constriction and clotting of platelets, and prostaglandin A₂ (PGA₂) is another prostaglandin that has been shown to have some antiviral/antitumor activity.

Terpenes are typically found as constituents of essential oils, they are mostly hydrocarbons and have a chemical structure of repeated isoprene units. Terpenes are secreted by many plants in order to offer protection from predators. Terpenes can be classified as monoterpenes, which are terpenes with 10 carbon atoms and two isoprene units; sesquiterpenes have 15 carbon atoms and three isoprene units; diterpenes have 20 carbon atoms and four isoprene units; triterpenes have 30 carbon atoms and six isoprene units; and tetraterpenes have 40 carbon atoms and eight isoprene units. Terpenes can also be classified based on the number of cyclic rings that are contained in their structures, i.e. acyclic, monocyclic, and bicyclic. Examples of terpenes are shown below.

Limonene has a lemon-orange smell and is found in the peels of citrus fruits and in other plants. Camphene is a colorless crystal with a camphor-like odor and is used as a food additive. Myrcene is used in the perfume industry, and α-pinene has a variety of uses, including healing properties.