Lack of effect of coumarin on the formation of micronuclei in an in vivo mouse micronucleus assay

Coumarin was tested for its potential to cause genotoxic effects in mouse b one marrow cells using an in vivo micronucleus assay. Male and female Swiss mice were administered a single oral dose of coumarin at 50, 100 or 200 mg /kg by gavage in corn oil vehicle. Control animals received only the vehicl e. Groups of male mice were also administered mitomycin C at 0.75 mg/kg and served as positive controls. At 24 h after treatment, mice from all dose l evels, and at 48 h after treatment, mice from the high dose level only were sacrificed. Bone marrow cells were collected and assayed for the presence of micronuclei. Coumarin did not cause any increase in the incidence of mic ronucleated polychromatic erythrocytes in male or female mice at any of the dose levels, the positive control mitomycin C produced a significant incre ase. There was no evidence of coumarin or mitomycin C treatment related cyt otoxicity to bone marrow cells. The results of this study demonstrate that coumarin is negative in the mouse in vivo micronucleus assay. (C) 2001 Else vier Science Ltd. All rights reserved.