Нооткатон

Identity

Nootkatone is a bicyclic sesquiterpene ketone. The (+)-form is named (4R,4aS,6R)-4,4a-dimethyl-6-prop-1-en-2-yl-3,4,5,6,7,8-hexahydronaphthalen-2-one. A second IUPAC name for the compound is 4α,5α-eremophila-1(10),11-dien-2-one.

Occurrence

Nootkatone is found in minute quantities in Alaska yellow cedar trees and grapefruit skin. (+)-Nootkatone has also been found in peel oils from orange, grapefruit, lemon, mandarin, and so on. The Alaska yellow cedar, Callitropsis nootkatensis, is a coniferous tree of the cypress family, native to the coastal regions of northwestern North America.

Properties

Nootkatone is practically insoluble in water. It is very soluble in ethanol, dichloromethane and ethyl acetate, and soluble in hexanes. It is soluble in alcohol and oil. The (+)-form has an optical rotation of +195.5 degrees (c = 1.5 in chloroform). It is stable under recommended storage conditions. Crystals can be obtained from light petroleum, while the commercial product is a colorless to yellowish liquid. Its density is 0.9963 at 25 °C.

Biosynthesis

A cytochrome P450 mono-oxygenase from chicory, CYP71AV8, catalyzes the regioselective oxidation of valencene and can be used for the biotechnological production of nootkatone. A tobacco enzyme, CYP71D51v2, oxidizes valencene predominantly to β-nootkatol. Nootkatone then forms from β-nootkatol through yeast components rather than through a cytochrome P450.

Taste

The taste of nootkatone is described as grapefruit, citrus, orange and bitter. Another description gives only a grapefruit taste.

Action against insects

Nootkatone in spray form is an effective repellent or insecticide against deer ticks. It is also an effective repellent or insecticide against mosquitos, and may repel bed bugs, head lice and Formosan termites. As is true of other plant terpenoids, nootkatone activates the α-adrenergic type 1 octopamine receptor (PaOA1) in susceptible arthropods, causing fatal spasms. Nootkatone appears to kill biting pests in a unique way, different from other insecticides already registered by the EPA, including pyrethroids, organophosphates, carbamates, and cyclodienes. Insecticides made with nootkatone may help in the fight against mosquitoes that have become resistant to existing insecticides. Repellents formulated with nootkatone may protect from bites at similar rates as products with other active ingredients already available, and can provide up to several hours of protection. Nootkatone is an active ingredient and not an end-use product. It is a volatile essential oil that does not persist in the environment. It is nontoxic to humans and is an approved food additive.

Explore all seven extraits in the Discovery Set.

—

Related: Buddhas Hand · Calamansi · Citronellal · Citrus Water · Citruses · Crystalfizz · Dihydromyrcenol · Dihydromyrcenol Acetate