Degradation, metabolism and toxicity of synthetic pyrethroids.
Degradation, metabolism and toxicity of synthetic pyrethroids.
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DOI：
10.1289/ehp.761415
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发表时间：
1976-04
影响因子：
10.4
通讯作者：
Miyamoto J
中科院分区：
文献类型：
--
作者：
Miyamoto J
合成拟除虫菊酯化合物在哺乳动物体内通过氧化和水解两种途径进行生物降解，根据化合物的类型，两种途径中的任一种可能占主导地位。因此，伯醇类化合物的（+）-或（+/-）-反式异构体，如苯菊酯、呋菊酯、炔丙菊酯、苄菊酯和胺菊酯（也可能是氯菊酯），主要通过酯键的水解代谢，随后氧化和/或结合组分醇和酸部分。另一方面，相应的（+）-顺式对映异构体和仲醇类化合物（如丙烯菊酯）对水解攻击具有抗性，并通过在分子的各个位点的氧化而生物降解。这些快速代谢降解，加上推测的胃肠道不完全吸收，通常会导致合成拟除虫菊酯的急性毒性较低。这些化合物既不是皮肤刺激物，也不是皮肤致敏物，吸入毒性和皮肤毒性相当低。在大鼠、小鼠和/或家兔中均无致畸性，对各种细菌菌株也无致突变性。对大鼠亚急性和慢性喂食较高剂量的化合物总是会导致肝脏发生一些组织病理学变化;然而，这些变化既不表明也不提示致瘤性。根据现有的毒理学信息，目前推荐的使用模式可能为人群提供足够的安全系数。然而，在将用途扩大到农业害虫控制方面，应该从化学和生物两个方面进行更广泛的调查，因为关于这些拟除虫菊酯在环境中的命运的信息很少。此外，几种化合物可能对某些种类的鱼类和节肢动物具有很强的毒性。
Synthetic pyrethroidal compounds undergo biodegradation in mammals both oxidatively and hydrolytically, and depending on the type of compound, either of the pathways may predominate. Thus, (+) - or (+/-) -trans isomers of the chrysanthemumate ester of primary alcohols such as fenothrin, furamethrin, proparthrin, resmethrin, and tetramethrin (and possibly permethrin, too) are metabolized mainly through hydrolysis of the ester linkage, with subsequent oxidation and/or conjugation of the component alcohol and acid moieties. On the other hand, the corresponding (+)-cis enantiometers and chrysanthemumate of secondary alcohols like allethrin are resistant to hydrolytic attack, and biodegraded via oxidation at various sites of the molecule. These rapid metabolic degradations, together with the presumable incomplete absorption from the gastrointestinal tract, would generally contribute to the low acute toxicity of synthetic pyrethroids. These compounds are neither skin irritants nor skin sensitizers, and inhalation toxicity as well as dermal toxicity are fairly low. Neither is teratogenic in rats, mice, and/or rabbits or mutagenic on various bacterial strains. Subacute and chronic feeding of higher amounts of the compounds to rats invariably causes some histopathological changes in liver; however, these are neither indicative nor suggestive of tumorigenicity. Based on existing toxicological information, the present recommended use patterns might afford sufficient safety margin on human population. However, in extending usage to agricultural pest control, much more extensive investigations should be forthcoming from both chemical and biological aspects, since there is scant information on the fate of these pyrethroids in the environment. Also several of the compounds may be very toxic to certain kinds of fish and arthropods.