Prunasin

Prunasin

Prunasin is a cyanogenic glycoside found in various plants, particularly in the Rosaceae family. It is a derivative of mandelonitrile and is known for its role in plant defense mechanisms. When plant tissues containing prunasin are damaged, the compound can be hydrolyzed to produce hydrogen cyanide, a potent toxin that deters herbivores and pathogens.

Chemical Structure and Properties

Prunasin is chemically classified as a glycoside, which means it consists of a sugar molecule (in this case, glucose) bonded to a non-sugar molecule (aglycone). The aglycone part of prunasin is mandelonitrile, which contains a cyanohydrin group. The chemical formula of prunasin is C14H17NO6.

Biosynthesis

Prunasin is synthesized in plants through a series of enzymatic reactions. The biosynthesis begins with the amino acid phenylalanine, which is converted into phenylacetaldehyde. This intermediate is then transformed into mandelonitrile, which is subsequently glycosylated to form prunasin.

Role in Plants

Prunasin serves as a defense compound in plants. When plant tissues are damaged, enzymes such as β-glucosidase come into contact with prunasin, leading to its hydrolysis. This reaction releases mandelonitrile, which further decomposes to produce benzaldehyde and hydrogen cyanide. The release of hydrogen cyanide is toxic to many herbivores and pathogens, providing a protective mechanism for the plant.

Occurrence

Prunasin is found in various members of the Rosaceae family, including species of the genera Prunus, Malus, and Pyrus. It is particularly abundant in the seeds and leaves of these plants.

Toxicity

The toxicity of prunasin is primarily due to its potential to release hydrogen cyanide. Ingestion of plant parts containing prunasin can lead to cyanide poisoning in humans and animals. Symptoms of cyanide poisoning include headache, dizziness, shortness of breath, and in severe cases, convulsions and death.

Related Compounds

Prunasin is structurally related to other cyanogenic glycosides such as amygdalin and linamarin. These compounds also release hydrogen cyanide upon hydrolysis and serve similar defensive roles in plants.

See Also

• Cyanogenic glycoside
• Hydrogen cyanide
• Rosaceae
• Amygdalin
• Linamarin