Abstract
O, S-Dibenzoyl thiamine hydrochloride (DBT-HCl) was tested by the rec-assay and the reversion assay. In the rec-assay with Bacillus subtilis strains H17 (Rec^+) and M45 (Rec^-), DBT-HCl gave negative results at a dose of 10mg/disk. When Escherichia coli strains B/rWP-2 and B/rWP-2hcr^-, and Salmonella typhimurium strains TA1535,TA1537,TA98 and TA100 were used in the reversion assay, DBT-HCl was not mutagenic in any of the indicator strains at concentrations ranging from 500 to 5,000μg/plate, irrespective of the treatment with mammalian metabolic activation system (S-9 mixture) prepared from phenobarbital-treated rat. Negative results were also obtained for sodium benzoate and sodium hippurate, the major metabolite of DBT, in the same test systems as above. From these results, it is concluded that DBT-HCl is not mutagenic under the present experimental conditions.
