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A pyrethroid is a synthetic chemical compound
Chemical compound

A chemical compound is a Chemical substance consisting of two or more different chemical element Chemical bond together in a fixed mass ratio that can be split into simpler substances....
 similar to the natural chemical pyrethrin
Pyrethrin

The pyrethrins are a pair of natural organic compounds that have potent insecticidal activity. Pyrethrin I and pyrethrin II are structurally related esters with a cyclopropane core....
s produced by the flowers of pyrethrum
Pyrethrum

'Pyrethrum' refers to several Old World plants of the genus Chrysanthemum which are cultivated as ornamentals for their showy flower heads. It is also the name of a natural insecticide made from the dried flower heads of C....
s (Chrysanthemum cinerariaefolium and C. coccineum). Pyrethroids are common in commercial products such as household insecticide
Insecticide

An insecticide is a pesticide used against insects in all developmental forms. They include ovicides and larvicides used against the Egg and larvae of insects respectively....
s and insect repellent
Insect repellent

An insect repellent is a substance applied to skin, clothing, or other surfaces which discourages insects from landing or climbing on that surface....
s. In the concentrations used in such products, they are generally harmless to human beings but can harm sensitive individuals. They are usually broken apart
Chemical decomposition

Chemical decomposition or analysis is the separation of a chemical compound into chemical element or smaller compounds. It is sometimes defined as the opposite of a chemical synthesis....
 by sunlight
Sunlight

Sunlight, in the broad sense, is the total spectroscopy of the electromagnetic radiation given off by the Sun. On Earth, sunlight is Filter ed through the Earth's atmosphere, and the solar radiation is obvious as daylight when the Sun is above the horizon....
 and the atmosphere in one or two days, and do not significantly affect groundwater
Groundwater

Groundwater is water located beneath the ground surface in soil porosity spaces and in the fractures of lithologic formations. A unit of rock or an unconsolidated deposit is called an aquifer when it can yield a usable quantity of water....
 quality except for being toxic to fish.

Pyrethroids are axonic poisons that work by keeping the sodium channels open in the neuronal membranes of insect
Insect

Insects are the biggest class of arthropods and the only ones with wings. They are the most diverse group of animals on the planet. They are most diverse at the equator and their diversity declines toward the poles....
s.






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Encyclopedia


A pyrethroid is a synthetic chemical compound
Chemical compound

A chemical compound is a Chemical substance consisting of two or more different chemical element Chemical bond together in a fixed mass ratio that can be split into simpler substances....
 similar to the natural chemical pyrethrin
Pyrethrin

The pyrethrins are a pair of natural organic compounds that have potent insecticidal activity. Pyrethrin I and pyrethrin II are structurally related esters with a cyclopropane core....
s produced by the flowers of pyrethrum
Pyrethrum

'Pyrethrum' refers to several Old World plants of the genus Chrysanthemum which are cultivated as ornamentals for their showy flower heads. It is also the name of a natural insecticide made from the dried flower heads of C....
s (Chrysanthemum cinerariaefolium and C. coccineum). Pyrethroids are common in commercial products such as household insecticide
Insecticide

An insecticide is a pesticide used against insects in all developmental forms. They include ovicides and larvicides used against the Egg and larvae of insects respectively....
s and insect repellent
Insect repellent

An insect repellent is a substance applied to skin, clothing, or other surfaces which discourages insects from landing or climbing on that surface....
s. In the concentrations used in such products, they are generally harmless to human beings but can harm sensitive individuals. They are usually broken apart
Chemical decomposition

Chemical decomposition or analysis is the separation of a chemical compound into chemical element or smaller compounds. It is sometimes defined as the opposite of a chemical synthesis....
 by sunlight
Sunlight

Sunlight, in the broad sense, is the total spectroscopy of the electromagnetic radiation given off by the Sun. On Earth, sunlight is Filter ed through the Earth's atmosphere, and the solar radiation is obvious as daylight when the Sun is above the horizon....
 and the atmosphere in one or two days, and do not significantly affect groundwater
Groundwater

Groundwater is water located beneath the ground surface in soil porosity spaces and in the fractures of lithologic formations. A unit of rock or an unconsolidated deposit is called an aquifer when it can yield a usable quantity of water....
 quality except for being toxic to fish.

Pyrethroids are axonic poisons that work by keeping the sodium channels open in the neuronal membranes of insect
Insect

Insects are the biggest class of arthropods and the only ones with wings. They are the most diverse group of animals on the planet. They are most diverse at the equator and their diversity declines toward the poles....
s. The sodium channel is a small hole through which sodium ions are permitted to enter the axon and cause excitation. As the nerves cannot de-excite, the insect is paralyzed.

Pyrethroids are usually combined with piperonyl butoxide
Piperonyl butoxide

Piperonyl butoxide is a pesticide synergy. It does not, by itself have pesticidal properties. However, when added to insecticide mixtures, typically pyrethrin, pyrethroid, and carbamate insecticides, their potency is increased considerably....
, a known inhibitor of key microsomal oxidase enzyme
Enzyme

Enzymes are biomolecules that catalysis chemical reactions. Almost all enzymes are proteins. In enzymatic reactions, the molecules at the beginning of the process are called Substrate , and the enzyme converts them into different molecules, the products....
s. This prevents these enzymes from clearing the pyrethroid from the body of the insect, and assures the pyrethroid will be lethal and not merely a paralyzing agent. Combined, pyrethroids are toxic to most beneficial insects such as bee
Bee

Bees are flying insects closely related to wasps and ants. Bees are a monophyly lineage within the superfamily Apoidea, presently classified by the unranked taxon name Anthophila....
s and dragonflies.

The pyrethroid chrysanthemic acid is produced industrially in a cyclopropanation reaction of a diene
Diene

Dienes or diolefins are hydrocarbons which contain two covalent bond. Dienes are intermediate between alkenes and polyenes....
 as a mixture of cis- and trans isomers followed by hydrolysis of the ester :

The compound is the starting material for many derivatives by re-esterfication.

Commercial Pyrethroid Insecticides/Repellants

  • Allethrin
    Allethrin

    The allethrins are a pair of related synthetic compounds used in insecticides. They are synthetic pyrethroids, a synthetic form of a chemical found naturally in the chrysanthemum flower....
    , the first pyrethroid synthesized (active ingredient of Raid
    Raid (insecticide)

    Raid is the brand name of a line of insecticides produced by SC Johnson, first launched in 1956.The initial active ingredient was the first synthetic pyrethroid, allethrin....
    )
  • Bifenthrin
    Bifenthrin

    Bifenthrin is a pyrethroid insecticide that affects the insect nervous system of insects. Products containing bifenthrin include Talstar, Capture, Brigade, Bifenthrine, Ortho Home Defense Max, and Scotts LawnPro Step 3....
    , active ingredient of Talstar, Capture, Ortho Home Defense Max, and Bifenthrine
  • Cypermethrin
    Cypermethrin

    Cypermethrin is a synthetic compound primarily used as an insecticide. It acts as a fast-acting neurotoxin in insects. It is easily degraded on soil and plants but can be effective for weeks when applied to indoor inert surfaces....
  • Deltamethrin
    Deltamethrin

    Deltamethrin is a pyrethroid ester insecticide....
  • Permethrin
    Permethrin

    Permethrin is a common chemical synthesis chemical, widely used as an insecticide, acaricide, and insect repellent. It belongs to the family of synthetic chemicals called pyrethroids and functions as a neurotoxin, affecting neuron cell membranes by prolonging sodium channel activation....
  • Prallethrin
    Prallethrin

    Prallethrin is a pyrethroid insecticide.References*...
  • Resmethrin
    Resmethrin

    Resmethrin is a pyrethroid insecticide with many uses, including control of the adult mosquito population. A commercial trade names for products that contain resmethrin are Chrysron, Crossfire, Pynosect, Raid Flying Insect Killer, Scourge, Sun-Bugger #4, SPB-1382, Synthrin, Syntox, Vectrin and Whitmire PT-110....
    , active ingredient of Scourge
  • Sumithrin, active ingredient of Anvil
    Anvil (insecticide)

    Anvil is an insecticide widely employed to combat West Nile Virus, a mosquito-borne disease identified in approximately 10,000 residents of the United States from 1999-2006....
  • Tetramethrin
    Tetramethrin

    Tetramethrin is a potent synthetic insecticide in the pyrethroid family. It is a white crystalline solid with a melting point of 65-80 ?C. The commercial product is a mixture of stereoisomers....
  • Tralomethrin
    Tralomethrin

    Tralomethrin is a pyrethroid insecticide.Tralomethrin has potent insecticidal properties; it kills by modifying the gating kinetics of the sodium channels in neurons, increasing the length of time the channel remains open after a stimulus, thereby depolarizing the neuron for a longer period of time....
  • Transfluthrin
    Transfluthrin

    Transfluthrin is a fast-acting pyrethroid insecticide with low persistency. It has the molecular formula C15H12Cl2F4O2....
    , active ingredient of Baygon
    Baygon

    Baygon is a pesticide brand produced by S. C. Johnson & Son. It is an insecticide used for extermination and control of many household pests and is very effective for crickets, roaches, ants, carpenter ants, spiders, silverfish, etc....
  • Imiprothrin, active ingredient of Raid
    Raid (insecticide)

    Raid is the brand name of a line of insecticides produced by SC Johnson, first launched in 1956.The initial active ingredient was the first synthetic pyrethroid, allethrin....
     Ant & Roach Killer    , synthesized to be an extremely fast-acting toxin by Sumitomo Chemical Co. in Canada.


Possible link to Autism


A recent study (2008), led by lead author Irva Hertz-Picciotto, professor in the Department of Public Health Sciences at University of California, Davis, suggested a correlation between pyrethrins and autism
Autism

Autism is a Neurodevelopmental disorder characterized by impaired social interaction and communication, and by restricted and repetitive behavior....
. In the study of 500 children (with or without autism), the 138 children with autism and their mothers were twice as likely to "report using pet shampoos and other household products containing pyrenthrins than other mothers". There is no causation link established, however, and the correlation, while considered to be statistically strong, needs to be investigated further.

External links

  • Estrogenic Potential of Certain Pyrethroid Compounds...