Antifeedants are

organic compound Some chemical authorities define an organic compound as a chemical compound that contains a carbon–hydrogen or carbon–carbon bond; others consider an organic compound to be any chemical compound that contains carbon. For example, carbon-co ...

s produced by plants to repel

herbivores A herbivore is an animal anatomically and physiologically evolved to feed on plants, especially upon vascular tissues such as foliage, fruits or seeds, as the main component of its diet. These more broadly also encompass animals that eat ...

through distaste or toxicity. These chemical compounds are typically classified as

secondary metabolite Secondary metabolites, also called ''specialised metabolites'', ''secondary products'', or ''natural products'', are organic compounds produced by any lifeform, e.g. bacteria, archaea, fungi, animals, or plants, which are not directly involved ...

s in that they are not essential for the metabolism of the plant, but instead confer longevity. Antifeedants exhibit a wide range of activities and chemical structures as biopesticides. Examples include

rosin Rosin (), also known as colophony or Greek pitch (), is a resinous material obtained from pine trees and other plants, mostly conifers. The primary components of rosin are diterpenoids, i.e., C20 carboxylic acids. Rosin consists mainly of r ...

, which inhibits attack on trees, and many

alkaloid Alkaloids are a broad class of natural product, naturally occurring organic compounds that contain at least one nitrogen atom. Some synthetic compounds of similar structure may also be termed alkaloids. Alkaloids are produced by a large varie ...

s, which are highly toxic to specific insect species, such as quassinoids (extracts from ''

Quassia ''Quassia'' ( or ) is a plant genus in the family Simaroubaceae. Its size is disputed; some botanists treat it as consisting of only one species, '' Quassia amara'' from tropical South America, while others treat it in a wide circumscription as ...

'' trees) against the diamondback moth ('' Plutela xylostella''). ''Samadera indica'' also has quassinoids used for insect antifeedant uses.

History

"Plant-derived insecticides (e.g., rotenone, veratridines,

pyrethrin The pyrethrins are a class of organic compounds normally derived from ''Chrysanthemum cinerariifolium'' that have potent Insecticide, insecticidal activity by targeting the nervous systems of insects. Pyrethrin naturally occurs in chrysanthemum f ...

s, and

nicotine Nicotine is a natural product, naturally produced alkaloid in the nightshade family of plants (most predominantly in tobacco and ''Duboisia hopwoodii'') and is widely used recreational drug use, recreationally as a stimulant and anxiolytic. As ...

) have been used for insect control since antiquity." The active ingredients in these plants have been purified and modified. For example, variations on pyrethrin have spawned a large number of synthetic insecticides called

pyrethroid A pyrethroid is an organic compound similar to the natural pyrethrins, which are produced by the flowers of pyrethrums (''Chrysanthemum cinerariaefolium'' and ''Chrysanthemum coccineum, C. coccineum''). Pyrethroids are used as commercial and hou ...

Culinary implications

In addition to their role defending the plant, antifeedants often confer taste or odors, enhancing the flavor of certain plants. Examples are provided by

cruciferous vegetables Cruciferous vegetables are vegetables of the family Brassicaceae (also called Cruciferae) with many genera, species, and cultivars being raised for food production such as cauliflower, cabbage, kale, garden cress, bok choy, broccoli, Brusse ...

including mustard,

cabbage Cabbage, comprising several cultivars of '' Brassica oleracea'', is a leafy green, red (purple), or white (pale green) biennial plant grown as an annual vegetable crop for its dense-leaved heads. It is descended from the wild cabbage ( ''B.& ...

, and

horseradish Horseradish (''Armoracia rusticana'', syn. ''Cochlearia armoracia'') is a perennial plant of the family Brassicaceae (which also includes Mustard plant, mustard, wasabi, broccoli, cabbage, and radish). It is a root vegetable, cultivated and us ...

, which release pungent oils containing

glucosinolates Glucosinolates are natural components of many pungent plants such as mustard, cabbage, and horseradish. The pungency of those plants is due to mustard oils produced from glucosinolates when the plant material is chewed, cut, or otherwise dama ...

when the plant material is chewed, cut, or otherwise damaged. The odorous components of

garlic Garlic (''Allium sativum'') is a species of bulbous flowering plants in the genus '' Allium''. Its close relatives include the onion, shallot, leek, chives, Welsh onion, and Chinese onion. Garlic is native to central and south Asia, str ...

are thought to have evolved to deter insects. File:GreenGarlic.png, Green

, which releases alliin upon cutting File:Patch of Tobacco (Nicotiana tabacum ) in a field in Intercourse, Pennsylvania..jpg, Tobacco plants, which produce

File:Chrysanthemum November 2007 Osaka Japan.jpg,

Chrysanthemum Chrysanthemums ( ), sometimes called mums or chrysanths, are flowering plants in the Asteraceae family. They are native to East Asia and northeastern Europe. Most species originate from East Asia, and the center of diversity is in China. Co ...

flowers, which contain

File:Armoracia rusticana.jpg,

plants, which release allyl isothiocyanate upon cutting

References

{{Secondary metabolites Biological pest control