Carcinogens chemical structures

Many compounds of this class hydrolyze to produce chloroanilines, which can cause anemia and methemoglobinemia. Such hydrolysis may occur both under acidic and alkaline conditions, and the degree of hydrolysis depends on the water solubility. Although these substances may form nitrosamines under certain conditions, there is no report of carcinogenicity. Chemical structures, physical properties, and toxicity data for a few selected herbicides of this class are presented in the following sections. 

Ashby, J., and D. Paton (1993). The Influence of Chemical Structure on the Extent and Sites of Carcinogenesis for 522 Rodent Carcinogens and 55 Different Human Carcinogen Estytosurts."Mutation Research 286, 3-74. 

Since the spectrum of dibenz [ ,]i]anthracene was not identical to that of the carcinogenic tars, carcinogenic activity obviously was not confined to a unique chemical structure and indeed Cook, who had joined this research effort in 1929, soon synthesized a number of new hydrocarbons, and many of these were carcinogenic. 

Ashby J, Tennant RW. 1990. Definitive relationships among chemical structure, carcinogenicity and mutagenicity for 301 chemicals tested by the U.S. NTP. Mutat Res 257 229-306. 

Loew CH, Rebagliati M, Poulsen M. 1984. Metabolism and relative carcinogenic potency of chloroethanes a quantum chemical structure-activity study. Cancer Biochem Biophys 7 109-132. 

Ashby, J. and Tennant, R.W. (1988). Chemical structure, Salmonella mutagenicity and extent of carcinogenicity as indices of genotoxic carcinogens among 222 chemicals tested in rodents by the US NCI/NTP. Mutation Res. 204 17-115. 

The carcinogenic aromatic amines released from azo dyes in leather were investigated by using microwave-assisted extraction (MAE) or supercritical fluid extraction (SFE) followed by RP-HPLC. The chemical structures of dyes and aromatic amines are listed in Fig. 3.69. The flow schemes for SFE and MAE are shown in Figs 3.70. and 3.71. 

Fig. 3.69. Chemical structures of the azo colourants together with the released carcinogenic amines investigated in this study. Reprinted with permission from C. S. Eskilsson et al. [140].

Many PAHs are present in smoke and other products of combustion, and in pitches and tars. Some are carcinogens, others are not carcinogenicity depends strongly upon details of chemical structure, specifically the ways in which the carbon rings are attached to each... 

Toxicologists have begun to understand how the chemical structure and some of the other properties of these chemicals contribute to their carcinogenicity. One important part of the effort to reduce reliance upon animal testing involves further validation of the use of chemical structure information along with other properties of a chemical - its... 

N-nitroso compounds are widely recognized as being unquestionably nasty materials. More, than 100 of the 130 different N-nitroso compounds tested in animals have been shown to be carcinogenic (1). The site of the tumor depends upon the chemical structure of the N-nitroso compound, the route of administration and the species being tested. Three N-nitroso compounds, N-nitrosodimethylamine (NDMA), N-nitrosodi-ethylamine (NDEA) and N-nitrosopyrrolidine (NPYR), have been tested in dose response studies with rats between 1 and 5 parts per million (ppm) of these nitrosamines in the diet was found to produce a marginally significant number of tumors in a rat population of under 100 animals [2, 3, 4). 

The chemical stmcture of a substance may contain structural alerts for genotoxicity and/or carcinogenicity, based on clear evidence for carcinogenicity of structural analogues. 

The prediction of genotoxicity based on chemical structure began in earnest after Ashby and Tennant [15,16] established that there are correlations between chemical structure. Salmonella mutagenicity and carcinogenicity - and that genotoxic and... 

In 1775, Pursevil Pott first noted that the compounds associated with soot caused scrotal cancer in British chimney sweeps (] ). Not having modern methods of Instrumental analysis available to him, Pott was unable to specify the chemical structures of these compounds. It remained until 1933 before Cook et al. identified the exact structure of benzo[a]pyrene and demonstrated its carcinogenicity ( ). Thus, polycyclic aromatic hydrocarbons (PAH) are one of the few groups of compounds which are known to be carcinogenic to man. 

It is not possible on the basis of present knowledge of the relationship of chemical structure to the carcinogenic activity of a chemical to predict how many of the millions of compounds in nature, or the tens of thousands of compounds in commerce, are carcinogenic. Although relatively few chemicals have been observed to cause cancer in human populations, those that have (Thble 5.1), and the himdreds of other substances for which there is some evidence of carcinogenicity in laboratory animals (Thble 5.2), include compounds of widely diverse structures. 

Ashby, J. and Paton, D. (1993) The influence of chemical structure on the extent and sites of carcinogenesis for 522 rodent carcinogens and 55 different human carcinogen exposures. Mutat. Res., 286, 3-74. 

The major concern as far as the potential carcinogenicity of veterinary drugs is concerned is directed toward their residues in edible animal products (49). The number of chemicals shown to be carcinogenic in animals has increased enormously over the past decade. They represent a wide spectrum of unrelated chemical structures, including many that are apparently nongenotoxic in most test systems. 

Table 4 Chemical Structure, Bacterial Mutagenicity In Vitro and Rat Carcinogenicity Data for Some...

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