Antifeedants are

organic compound In chemistry, organic compounds are generally any chemical compounds that contain carbon- hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. Th ...

s produced by plants to inhibit attack by insects and grazing animals. These chemical compounds are typically classified as

secondary metabolite Secondary metabolites, also called specialised metabolites, toxins, secondary products, or natural products, are organic compounds produced by any lifeform, e.g. bacteria, fungi, animals, or plants, which are not directly involved in the no ...

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, which inhibits attack on trees, and many

alkaloid Alkaloids are a class of basic BASIC (Beginners' All-purpose Symbolic Instruction Code) is a family of general-purpose, high-level programming languages designed for ease of use. The original version was created by John G. Kemeny and Th ...

s, which are highly toxic to specific insect species.

History

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

veratridine Veratridine is a steroidal alkaloid found in plants of the lily family, specifically the genera '' Veratrum'' and '' Schoenocaulon''. Upon absorption through the skin or mucous membranes, it acts as a neurotoxin by binding to and preventing the in ...

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

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

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

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, Brussels s ...

including mustard, cabbage, and

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

, which release pungent oils containing glucosinolates when the plant material is chewed, cut, or otherwise damaged. The odorous components of

garlic Garlic (''Allium sativum'') is a species of bulbous flowering plant in the genus ''Allium''. Its close relatives include the onion, shallot, leek, chive, Welsh onion and Chinese onion. It is native to South Asia, Central Asia and northe ...

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

, which releases

alliin Alliin is a sulfoxide that is a natural constituent of fresh garlic. It is a derivative of the amino acid cysteine. When fresh garlic is chopped or crushed, the enzyme alliinase converts alliin into allicin, which is responsible for the aroma o ...

upon cutting File:Patch of Tobacco (Nicotiana tabacum ) in a field in Intercourse, Pennsylvania..jpg,

Tobacco plant ''Nicotiana'' () is a genus of herbaceous plants and shrubs in the family Solanaceae, that is indigenous to the Americas, Australia, Southwestern Africa and the South Pacific. Various ''Nicotiana'' species, commonly referred to as tobacco plants ...

s, which produce nicotine File:Chrysanthemum November 2007 Osaka Japan.jpg,

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

flowers, which contain

File:Armoracia rusticana.jpg,

plants, which release allyl isothiocyanate upon cutting

References

{{Secondary metabolites Biological pest control