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in vitro gene mutation study in bacteria
Type of genotoxicity: gene mutation
Type of information:
Adequacy of study:
weight of evidence
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Acceptable, well documented publication which meets basic scientific principles.
Justification for type of information:
QSAR prediction: migrated from IUCLID 5.6

Data source

Reference Type:
In-silico screening of high production volume chemicals for mutagenicity using the MCASE QSAR expert system
Klopman, G., Chakravarti, S.K., Harris, N., Ivanov, J. and Saiakhov, R.D.
Bibliographic source:
SAR and QSAR in Environmental Research, 14(2), 165-180

Materials and methods

Principles of method if other than guideline:
The MCASE-program, a quantitative structure-activity relational expert system (QSAR-ES), was used in this study. The program identifies structural features believed to be responsible for activity and is particularly suitable for handling large databases with diverse chemical sturctures. Previous experience has shown that the Salmonella assay is well adapted for use in computer expert systems for mutagenicity prediciton. Results are presented for batch screening of 2484 HPV chemicals to predict their mutagenicity in Salmonella thyphimurium. The chemicals were tested against 15 databases for salmonella strains TA 100, TA 1535, TA 1537, TA 97 and TA 98, both with metabolic activation (using rat liver and hamster liver S9 mix test) and without metabolic activation.
GLP compliance:
Type of assay:
other: QSAR

Test material

Constituent 1
Chemical structure
Reference substance name:
EC Number:
EC Name:
Cas Number:
Molecular formula:
Details on test material:
- Name of test material (as cited in study report): Phenol, 4-methyl-2-[(2-notrophenyl)azo]-


Target gene:
Species / strain
Species / strain / cell type:
S. typhimurium, other: TA 100, TA 1535, TA 1537, TA 97 and TA 98
Metabolic activation:
with and without
Metabolic activation system:
rat and hamster liver metabolic activation
Evaluation criteria:
The result for a test of one chemical against an individual strain was categorized as "active", "inactive", or "marginal". These three possible outcomes were assigned scores of 2.0 (active), -1.0 (inactive) and 0.0 (marginal). Chemicals that were predicted as active with only a low degree of statistical certainty were categorized as "equivocal active" and assigned a score of 1.0. Similarly, an "equivocal inactive" result is assigned a score of -0.5. For each chemical, three composite scores were computed: (1) sum of individual scores for each of the five Salmonella strain modules without metabolic activation; (2) sum of scores for five modules with rat liver metabolic activation and (3) sum of scores for five modules with hamster liver metabolic activation.

Results and discussion

Test results
Species / strain:
S. typhimurium, other: TA 100, TA 1535, TA 1537, TA 97 and TA 98
Metabolic activation:
with and without

Any other information on results incl. tables

The scores for Phenol, 4-methyl-2-[(2-nitrophenyl)azo]- were:

(1): 3.0;

(2): 1.0;

(3): 4.0;

In this assessment, phenol, 4-methyl-2-[nitrophenyl)azo]- was in the group of chemicals that surfaced as possible mutagens. The chemicals in this group are expected to be highly mutagenic.

Applicant's summary and conclusion