Effect of various alkyl and unsaturated substituents on the mutagenicity of some nitrophenyl thioethers

In silico prediction of the mutagenicity of nitroaromatic compounds using a novel two-QSAR approach

Certain drugs are nitroaromatic compounds, which are potentially toxic. As such, it is of practical importance to assess and predict their mutagenic potency in the process of drug discovery. A classical quantitative structure-activity relationship (QSAR) model was developed using the linear partial least square (PLS) scheme to understand the underline mutagenic mechanism and a non-classical QSAR model was derived using the machine learning-based hierarchical support vector regression (HSVR) to predict the mutagenicity of nitroaromatic compounds based on a series of mutagenicity data (TA98-S9). It was observed that HSVR performed better than PLS as manifested by the predictions of the samples in the training set, test set, and outlier set as well as various statistical validations. A mock test designated to mimic real challenges also confirmed the better performance of HSVR. Furthermore, HSVR exhibited superiority in predictivity, generalization capabilities, consistent performance, and robustness when compared with various published predictive models. PLS, conversely, revealed some mechanistically interpretable relationships between descriptors and mutagenicity. Thus, this two-QSAR approach using the predictive HSVR and interpretable PLS models in a synergistic fashion can be adopted to facilitate drug discovery and development by designing safer drug candidates with nitroaromatic moiety.

Influence of structural and functional modifications of selected genotoxic carcinogens on metabolism and mutagenicity - a review

Alterations in molecular structure are responsible for the differential biological response(s) of a chemical inside a biosystem. Structural and functional parameters that govern a chemical's metabolic course and determine its ultimate outcome in terms of mutagenic/carcinogenic potential are extensively reviewed here. A large number of environmentally-significant organic chemicals are addressed under one or more broadly classified groups each representing one or more characteristic structural feature. Numerous examples are cited to illustrate the influence of key structural and functional parameters on the metabolism and DNA adduction properties of different chemicals. It is hoped that, in the event of limited experimental data on a chemical's bioactivity, such knowledge of the likely roles played by key molecular features should provide preliminary information regarding its bioactivation, detoxification and/or mutagenic potential and aid the process of screening and prioritising chemicals for further testing.

Mutagenicity of sulfoscanate: a comparative study

The mutagenic activity of sulfoscanate (SSC) (4-isothiocyanate-4'-nitrodiphenyl sulphide) has been compared with that of the following reported drugs: (a) nitroscanate (NSC) (4-isothiocyanate-4'-nitrodiphenyl ether) which is a veterinary anthelmintic drug and (b) amoscanate (ASC) (4-isothiocyanate-4'-nitrodiphenyl amine) which is effective against schistosomes. SSC has been found to be a very potent mutagen towards TA98 and TA100 inducing 26.0 and 475.5revertants/nmole, respectively. NSC was found to induce mutations at a rate of 11.1 and 21.5revertants/nmole in TA98 and TA100, respectively. ASC was found to be non-mutagenic as such, but the urine of animals given the drug displayed mutagenicity. When SSC was tested in TA98/1,8-DNP(6), deficient in O-acetyltransferase, the activity decreased to 10.0revertants/nmole. However, in case of NSC the mutagenic activity was reduced to 0.24revertants/nmole, indicating the importance of O-acetyltransferase in generating N-acetoxyarylamine. In TA98NR, deficient in nitroreductase, the mutagenicity of SSC and NSC was totally absent. The positional isomers of SSC, 4-isothiocyanate-3'-nitro- and 4-isothiocyanate-2'-nitrodiphenyl sulphide, were found to be non-mutagenic in both TA98 and TA100. Our comparison of the mutagenic activity of SSC, NSC and ASC indicates that the pattern of activity is SSC>NSC>ASC.