Effects of 10-hydroxycamptothecin on induced chromosome aberrations in Chinese hamster ovary cells and micronuclei in mouse bone marrow and fetal liver

10-Hydroxycamptothecin (HC) is a new antitumor principle isolated from Camptotheca acuminata indigenous to China. The genetic toxicity of HC was assessed by mouse bone marrow and transplacental micronucleus test as well as Chinese hamster ovary cell chromosomal aberrations. All of these tests showed positive results. The highest rate of chromosomal aberrations was 83% at 0.125 microgram/ml for 48 h. The number of micronucleated polychromatic erythrocytes in bone marrow of mice was remarkably increased in 19.8% cells at 12.5 mg/kg for 24 h. The micronucleus formation was most often seen at 16 h after im HC in fetal liver and 24 h in maternal bone marrow. The peaks were 36 +/- 19 and 31 +/- 10%, respectively. The results from in vivo and in vitro suggest HC is a mutagen, furthermore, a transplacental mutagen in mouse.