Tebufenpyrad is an
insecticide
Insecticides are substances used to kill insects. They include ovicides and larvicides used against insect eggs and larvae, respectively. Insecticides are used in agriculture, medicine, industry and by consumers. Insecticides are claimed to b ...
and
acaricide widely used in
greenhouse
A greenhouse (also called a glasshouse, or, if with sufficient heating, a hothouse) is a structure with walls and roof made chiefly of Transparent ceramics, transparent material, such as glass, in which plants requiring regulated climatic condit ...
s. It is a white solid chemical with a slight aromatic smell. It is soluble in water and also in organic solvents.
[http://toxnet.nlm.nih.gov/cgi-bin/sis/search/a?dbs+hsdb:@term+@DOCNO+7271 ]
Mode of action
Tebufenpyrad is a strong
mitochondrial complex I
Respiratory complex I, (also known as NADH:ubiquinone oxidoreductase, Type I NADH dehydrogenase and mitochondrial complex I) is the first large protein complex of the respiratory chains of many organisms from bacteria to humans. It catalyzes the ...
inhibitor. Like
Rotenone, it inhibits electron transport chain by inhibiting the complex I enzymes of mitochondria which ultimately leads to lack of
ATP
ATP may refer to:
Companies and organizations
* Association of Tennis Professionals, men's professional tennis governing body
* American Technical Publishers, employee-owned publishing company
* ', a Danish pension
* Armenia Tree Project, non ...
production and finally cell death.
Use
Tebufenpyrad is used mainly in greenhouses around the world. It has been registered under various trade names (i.e.Masai, Pyranica)
in countries like
Australia
Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...
,
China
China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...
and certain
South American countries. It is registered in
USA
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country Continental United States, primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., ...
for use on ornamental plants in commercial green houses.
[ The data available presented enough evidence to support unconditional registration of tebufenpyrad for use on ornamental plants in greenhouses.][
]
Exposure and toxicity
It is mainly used in greenhouses and the major form of exposure is through occupational exposure where this chemical is manufactured or used extensively. The possible routes of exposure are through inhalation or dermal exposure.[MacBean C, ed. Tebufenpyrad (119168-77-3). In: The e-Pesticide Manual, 15th Edition, Version 5.0.1 (2011–2012). Surrey UK, British Crop Protection Council]
Biotransformation
Hydroxylation
In chemistry, hydroxylation can refer to:
*(i) most commonly, hydroxylation describes a chemical process that introduces a hydroxyl group () into an organic compound.
*(ii) the ''degree of hydroxylation'' refers to the number of OH groups in a ...
is the major and primary biotransformation of tebufenpyrad reported both ''in vivo'' and ''in vitro''. Ethyl and tetra-butyl groups are the targets of hydroxylation. The alcohol groups are oxidized to carboxylic groups which can then be conjugated with other groups ''in vivo''.
In rodent studies it was shown that 80% of the pesticide
Pesticides are substances that are meant to control pests. This includes herbicide, insecticide, nematicide, molluscicide, piscicide, avicide, rodenticide, bactericide, insect repellent, animal repellent, microbicide, fungicide, and lampri ...
was absorbed mainly in the digestive system within 24 hours, the major metabolites being the hydroxylated forms. Most of the compound and its metabolites were excreted through feces and urine. There was no evidence of accumulation in the body of the rodents.[
The metabolites excreted out differed from male to female in rodents. While males excreted the carboxylic derivatives of the parent compound, the female rats excreted the sulfate conjugates of carboxylic acid. The LD50 values of male and female rats was very different. While the LD50 value of female rats was 997 mg/kg the LD50 for male rats was only 595 mg/kg.]
Consequences of exposure
Tebufenpyrad exposure has been linked to cancer but to date no human data has been conclusive enough to link the two.[USEPA Office of Pesticide Programs, Health Effects Division, Science Information Management Branch: "Chemicals Evaluated for Carcinogenic Potential" (April 2006)]
Recently this pesticide has been shown to affect the dopaminergic neuronal cell lines N27 by disrupting the mitochondrial dynamics. Loss of dopaminergic cells have been linked to Parkinson's disease
Parkinson's disease (PD), or simply Parkinson's, is a long-term degenerative disorder of the central nervous system that mainly affects the motor system. The symptoms usually emerge slowly, and as the disease worsens, non-motor symptoms becom ...
in which the neuronal mitochondria are affected.spider mite
Spider mites are members of the Tetranychidae family, which includes about 1,200 species. They are part of the subclass Acari (mites). Spider mites generally live on the undersides of leaves of plants, where they may spin protective silk webs, a ...
species in apple trees in Western Australia.
References
{{Reflist
Insecticides
Acaricides
Pyrazoles
Tert-butyl compounds