4-nitrophenol

Endpoint summary

Additional information

In the toxicological profile on 4 -nitrophenol, toxicological studies are reviewed. Several genotoxicity tests, performed in procaryotes and mammalian cells, are cited. One test in Bacillus subtilis was reported to be positive for DNA damage when tested in the absence of metabolic activation. The authors of this test stated that the assay appears to be more sensitive for nitro compounds than the standardassay. Two further tests are cited which show a weakly positive result in the absence of metabolic activation (AMES test in P. mirabilis and DNA synthesis inhibition test in CHO cells). However, all of these test were performed without metabolic activation and, thererfore, provide only limited evidence on the genotoxic potential of 4 -nitrophenol in vivo. All of the other genotoxicity tests (13 out of 16) on 4 -nitrophenol, includingassays, DNA repair tests and forward mutation assays, were negative.

 

In the CICAD on 4 -Nitrophenol, the results of several in vitro genotoxicity studies are summarized.

Some, but not all of the studies using bacterial cells as well as investigations in human lymphocytes and in human fibroblasts were cited to show positive results in the absence of metabolic activation. However, to conclude on the mutagenic potential of 4 -Nitrophenol in vivo, the assays performed in the presence of metabolic activation are more relevant as these reflect more the in vivo situation. From the studies performed in the presence of metabolic activation, only two out of eleven gave positive results; one assay in E. coli and one study using chinese hamster ovary cells. The other studies on 4-Nitrophenol with metabolic activation gave negative results, including several Ames-tests, sister chromatid exchange and forward mutation assay in mammalian cells and gene mutation in E. coli.

 

In the NTP technical report on the toxicology and carcinogenesis studies of p-Nitrophenol, several in vitro studies and one in vivo study on p-Nitrophenol have been reviewed. Only those studies with adequate data presentation, study design, dose levels, endpoint evalution and/or information on chemical purity were chosen for the review.

None of the studies cited, including investigations in E. coli and Serrantia marcescens, as well as Ames-Test in S. typhimurium strains, chromosomal aberration tests and chromatid exchange assays in Chinese hamster ovary cells and studies on induction of sex-linked recessive lethal mutation in Drosophila melanogaster, showed genotoxic potential of the test substance.

 

In the BUA report on 4-nitrophenol, the results of several genotoxicity test are summarized. From 12 bacterial genotoxicity tests, only in one case for one S. typhimurium strain (TA1538) a positive result in the absence of S9-mix is reported, which was stated to be negative in other studies. Thus, in the bacteriological test systems, 4-nitrophenol was proven to be non-mutagenic. In addition, several other in vitro genotoxicity test are cited in the review. 4-nitrophenol was only stated to have mutagenic effects at very high concentrations of the test substance in a mitotic gene conversion assay, a DNA repair assay in a mutant P. mirabilis strain, a DNA cell binding assay and a DNA repair test in B. subtilis. All the other in vitro tests (DNA damage/repair, sex-linked recessive lethal test in Drosophila, point mutation assay) were negative at any concentration tested.

  

The overall evidence indicates that 4-nitrophenol is non-mutagenicin the presence and in the absence of metabolic activation when tested in vitro.

Short description of key information:
The results of different in vitro genotoxicity tests has been reviewed in different reports (a summary on the information is given under "discussion").
The overall evidence indicates that 4-nitrophenol is non-mutagenic in the presence and in the absence of metabolic activation when tested in procaryotes and mammalian cells.

Endpoint Conclusion: No adverse effect observed (negative)

Justification for classification or non-classification

Based on the results of the studies and taking into account the provisions laid down in Council Directive 67/548/EEC and CLP (1272/2008/EC), PNF is

non-mutagenicin the presence and in the absence of metabolic activation when tested in vitro and, therefore, no classification with respect to genetic toxicity is required.