Carbamate compounds toxicity

Carbaryl has been widely used as an insecticide on lawns or gardens. It has a low toxicity to mammals. Carbofuran has a high water solubility and acts as a plant systemic insecticide. It is taken up by the roots and leaves of plants so that insects feeding on the plant material are poisoned by the carbamate compound in it. 

For example, no difference in the toxicity of organophosphorus compounds to larvae of the midge Chrironomus riparius was observed between pulsed and continuous exposures (Kallander et al. 1997). In the same study, however, two 1-hour pulses caused significantly fewer symptoms of intoxication than 2 hours of continuous exposure to carbamate compounds, when animals were placed in clean water for at least 2 to 6 hours between treatments (Kallander et al. 1997), suggesting that detoxification or elimination of the toxicant during the toxicant-free period can reduce the toxic effects of the earlier exposures. 

In parallel to these studies, carbamate compounds 1 and 11-14 were assessed for their antitumor efficacy in mouse cancer xenograft models.15 When implanted human colon cancer CXF280 xenografts were grown within mice for fourteen days, doses of test compounds were administered orally. After a three-week regimen, excised tumor volumes were measured and the percent inhibition of tumor growth was calculated. From this investigation, capecitabine (1) was found to be the most effective treatment, and was furthermore found not to cause intestinal toxicity.16 All of these preclinical observations contributed to the selection of capecitabine as a candidate for further development. 

Fonnum, F., Sterri, S.H. (2006). Tolerance development to toxicity of cholinesterase inhibitors. In Toxicology of Organ-ophosphate and Carbamate Compounds (R.C. Gupta, ed.), pp. lSl-61. Elsevier Academic Press, San Diego, CA. 

Costa LG, Cole TB, Vitalone A et al. (2005). Paraoxonase polymorphisms and toxicity of organophosphates. In Toxicology of Organophosphate and Carbamate Compounds. (R Gupta, ed.) pp. 247-255. San Diego, CA, USA Academic Press. 

Organophosphorus and carbamate compounds have come into widespread use in agriculture, since they show low environmental persistence nevertheless, they exert a high acute toxicity. The principal effect of these compounds is the inhibition of the enzyme acetylcholinesterase (AChE), which is essential for terminating the action of the neurotransmitter acetylcholine (ACh). Actually, the intoxication by these compounds results in... 

TABLE 11. RELATIVE TOXICITIES OF ORGANOPHOSPHORUS AND CARBAMATE COMPOUNDS (CONTINUED) ... 

Pelkonen, O., Vahakangas, K., Gupta, R.C., 2006. Placental toxicity of organophosphate and carbamate pesticides. In Gupta, R.C (Ed.), Toxicology of Organophosphate and Carbamate Compounds Elsevier Academic Press, New York, NY, pp. 463 79. 

P. J. Bushnell and V. C. Moser, Behavioral toxicity of cholinesterase inhibitors in Toxicology of Organophosphate and Carbamate Compounds, ed. R. Gupta, Academic Press, San Diego, 2006, pp. 347-360. 

Environmental. The A/-methylcarbamates generally are biodegradable and of low soil persistence with half-Hves for carbaryl and aldicarb of 1—2 weeks and of carbofuran of 1—4 months. Certain carbamates are highly toxic to birds with oral LD qS for mallard, eg, pheasant, in mg/kg carbofuran, 0.40, 4.2 mexacarbate, 3.0, 4.5 and methomyl, 16, 15 compared to carbaryl >2000. Fish toxicity of carbamates is generally low, but these compounds are extremely toxic to bees. In cases of human poisoning, atropine is a specific antidote. 

The carbamate and OP insecticides and the organophosphorous nerve gases soman, sarin, and tabun all act as anticholinesterases, and most of their toxicity is attributed to this property. The naturally occurring carbamate physostigmine, which has been used in medicine, is also an anticholinesterase. Some OP compounds can cause relatively long-lasting inhibition of the enzyme because of the phenomenon of... 

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