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Key value for chemical safety assessment

Additional information

Three new in vitro mutagenicity studies have been conducted on KGA. In a standard Ames test, Salmonella typhimuirum strains TA1537, TA1535, TA102, TA98, and TA100, were exposed to concentrations ranging from 5 to 5000 ug/plate of KGA in both the presence and absence of S9. No treatment cultures showed mutation frequencies significantly greater than negative controls and therefore KGA is not mutagenic in either the presence or absence of metabolic activation.

In a second study, the chromosome aberration test in CHO V79 cells was used to assess mutagenicity of KGA. No mutagenicity or clastogenicity was observed in the presence of S9 activation. The results in the absence of S9 activation were more equivocal. In that portion of the study, structural chromosome aberrations were noted in two of the dose groups, though there was no dose-dependency. Despite this uncertainty, the criteria for a clastogenic test item were met so KGA would technically be considered to be clastogenic in the absence of S9 mix. However, no clastogenicity was observed in the presence of S9 mix, which suggests that metabolism reduces the potential for effects.

In a third study, the potential of 2 -Keto-L-gulonic acid anhydrous (KGA) to induce mutations at the mouse lymphoma thymidine kinase locus using the cell line L5178Y was examined. Results of the study indicate that under the experimental conditions reported the test item did not induce mutations in the mouse lymphoma thymidine kinase locus assay using the cell line L5178Y in the absence and presence of metabolic activation.

The combined results of the three in vitro studies indicate that KGA and KGA Greens are not likely to be mutagenic.

Short description of key information:
Three new in vitro mutagenicity studies are available on KGA. Combined they indicate that KGA and KGA Greens are not likely to be mutagenic.

Endpoint Conclusion: No adverse effect observed (negative)

Justification for classification or non-classification

Three new in vitro mutagenicity studies are available on KGA. Results were negative for mutagenicity in all tests and under all conditions with the exception of some non-dose responsive clastogenicity in the chromosome aberration test in the absence of S9 activation. Therefore, based on the combined results of the three studies, KGA and KGA Greens are not classified for genetic toxicity.