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Antifeedants are organic compounds produced by plants to inhibit attack by insects and grazing animals. These chemical compounds are typically classified as secondary metabolites 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 alkaloids, which are highly toxic to specific insect species.
File:GreenGarlic.png, Green
Antifeedants are organic compounds produced by plants to inhibit attack by insects and grazing animals. These chemical compounds are typically classified as secondary metabolites 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 alkaloids, 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 inac ...
s, pyrethrins, and nicotine
Nicotine is a naturally produced alkaloid in the nightshade family of plants (most predominantly in tobacco and ''Duboisia hopwoodii'') and is widely used recreationally as a stimulant and anxiolytic. As a pharmaceutical drug, it is used fo ...
) 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 pyrethroids.
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 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.&nb ...
, and horseradish, 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, Allium fistulosum, Welsh onion and Allium chinense, Chinese onion. It is native to South A ...
are thought to have evolved to deter insects.
garlic
Garlic (''Allium sativum'') is a species of bulbous flowering plant in the genus ''Allium''. Its close relatives include the onion, shallot, leek, chive, Allium fistulosum, Welsh onion and Allium chinense, Chinese onion. It is native to South A ...
, 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 of ...
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
Nicotine is a naturally produced alkaloid in the nightshade family of plants (most predominantly in tobacco and ''Duboisia hopwoodii'') and is widely used recreationally as a stimulant and anxiolytic. As a pharmaceutical drug, it is used fo ...
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 pyrethrin
File:Armoracia rusticana.jpg, horseradish plants, which release allyl isothiocyanate upon cutting
References