Abstract: Objective To evaluate the genotoxicity of Tongguan san and provide safety data for evaluation of its clinical medication.Methods The in vitro bacterial reverse mutation (Ames) test, in vitro Chinese hamster lung cell (CHL) chromosome aberration test, and the mouse bone marrow micronucleus test were conducted to study the genetic toxicity of Tongguan san. In Ames test, there were five dose groups respectively as follows: 312.5、625.0、1250.0, 2500.0 and 5000.0 μg/plate. In CHL chromosome aberration assay, the doses were 125.0、250.0 and 500.0 μg/mL respectively while the exposure time was 6 and 24 h respectively. In vivo micronucleus assay, there were three dose groups: 1250.0、2500.0 and 5000.0 mg/kg, for 7 days, once per day.Results In the Ames test, under S9 metabolism and non-metabolic activation, the numbers of five strains of revertant colonies did not show any dose-dependent increase when the Tongguan san concentration ranged from 312.5 to 5000.0μg/plate, and the result of Ames test was negative. In CHL chromosome aberration test, under S9 metabolism and non-metabolic activation, there was no significant difference in the chromosome aberration rate between the control group and dosing groups of Tongguan san (P >0.05), so there was no dose-response relationship. In the micronucleus test of mouse bone marrow cells, the micronuclei rates of mice bone marrow cells in each dosing group of Tongguan san were not significantly different from those of the solvent control (P>0.05).Conclusion Under this test condition, there is no potential genotoxicity in Tongguan san.

Key words: Tongguan san, genotoxicity, Ames test, CHL chromosome aberration assay, micronucleus assay