Allethrins Explained

The allethrins are a group of related synthetic compounds used in insecticides. They are classified as pyrethroids, i.e. synthetic versions of pyrethrin, a chemical with insecticidal properties found naturally in Chrysanthemum flowers. They were first synthesized in the United States by Milton S. Schechter in 1949. Allethrin was the first pyrethroid.^[1]

They are commonly used in ultra-low volume sprays for outdoor mosquito control, and in many household insecticides such as RAID, as well as mosquito coils.

Chemical structure

Allethrin I and allethrin II differ by having a methyl group and a methyl ester, respectively, on one terminus. Each of these allethrins consists of the eight possible stereoisomers. A partly enantiopure variant of allethrin I, consisting of only two stereoisomers in an approximate ratio of 1:1, is called bioallethrin. The same mixture of isomers, but in an approximate ratio of 3:1, is known as esbiothrin.

Toxicity

Chronic exposure to allethrins alters the plasma biochemical profile of humans and may have adverse health effects.^[2] Bioallethrin has been shown to cause oxidative damage, cellular toxicity and necrosis of human lymphocytes studied in vitro.^[3] It is highly toxic to fish and aquatic invertebrates. At normal application rates, allethrin is slightly toxic to bees.^[4] Insects subject to exposure become paralyzed (nervous system effect) before dying. Allethrins are toxic to cats^[5] because they either do not produce, or produce less of certain isoforms of glucuronosyltransferase, which serve in hepatic detoxifying metabolism pathways.^[6]

References

• Oregon State University (1996). Allethrin. Retrieved October 26, 2005.
• Illinois Department of Public Health Pyrethroid Insecticides Fact Sheet. Retrieved October 26, 2005.
• World Health Organization (WHO) d-Allethrin. Retrieved October 26, 2005.
• Jim E. Riviere & Mark G. Papich Eds.: Veterinary Pharmacology and Therapeutics. Iowa State University Press, 2009. . (p. 1194)

External links

• Pyrethrins and Pyrethroids Fact Sheet - National Pesticide Information Center
• Allethrin Pesticide Information Profile - Extension Toxicology Network

Notes and References

1. Ujihara . Kazuya . The history of extensive structural modifications of pyrethroids . Journal of Pesticide Science . 25 July 2019 . 44 . 4 . 215–224 . 10.1584/jpestics.D19-102 . 31777441 . 6861428 .
2. Narendra . M. . Kavitha . G. . Helah Kiranmai . A. . Raghava Rao . N. . Varadacharyulu . N.C. . Chronic exposure to pyrethroid-based allethrin and prallethrin mosquito repellents alters plasma biochemical profile . Chemosphere . September 2008 . 73 . 3 . 360–364 . 10.1016/j.chemosphere.2008.05.070. 18657844 . 2008Chmsp..73..360N .
3. Arif . Amin . Quds . Ruhul . Mahmood . Riaz . Bioallethrin enhances generation of ROS, damages DNA, impairs the redox system and causes mitochondrial dysfunction in human lymphocytes . Scientific Reports . December 2021 . 11 . 1 . 8300 . 10.1038/s41598-021-87799-3. 33859309 . 8050322 .
4. Web site: Pesticide Information Profile - Allethrin . pmep.cce.cornell.edu.
5. Web site: Pyrethrin and Permethrin Toxicity in Dogs and Cats . peteducation.com . 2013-05-12 . https://archive.today/20240526154343/https://www.webcitation.org/6Gst21cUu?url=http://www.peteducation.com/article.cfm%3Fc=2+1677 . 2024-05-26 . dead .
6. Court . M. H. . Greenblatt . D. J. . Molecular genetic basis for deficient acetaminophen glucuronidation by cats: UGT1A6 is a pseudogene, and evidence for reduced diversity of expressed hepatic UGT1A isoforms . Pharmacogenetics . 10 . 4 . 355–369 . 2000 . 10862526 . 10.1097/00008571-200006000-00009.