Abstract: Objective To observe the inhibitory effects of Platycodon grandiflorum(Jaoq.) A.DC on micronuclei frequencies induced by MMC in the bone marrow cells of mice. Methods Fifty mice were divided into groups: negative control (N·S), positive control (MMC 0.4 mg·kg^-1), Platycodon Grandiflorum(Jaoq.)A.DC mutagenesis groups (1.0、2.0、4.0 and 8.0g·kg^-1, which were matched5、10、20、40 clinical commonly used dosage ofa person) Platycodon Grandiflorum(Jaoq.)A.DC antimutagenesis groups ( MMC 30mg·kg ^-1 + each Platycodon Grandiflorum(Jaoq.)A.DC dosage Platycodon Grandiflorum(Jaoq.)A.DC groups), 5 mice per groups. MMC are given by drug abdominal cavity Injection, other drug are given by perfusing stomach. Platycodon Grandiflorum(Jaoq.)A.DCand MMC are given simultaneously in antimutagenesis groups, oncea day for 5 days successively. At the 5th weekend after the first administration, the mice are killed by cervical vertebra dislocation whose marrow are drawed and sheets are produced in our laboratory method. Results the micro-nuclei frequencies was no significant difference between tested groups and control group(P<0.05), but the frequency of micronucle induced by MMC was reduced by intragastrial perfusion of Platycodon Grandiflorum(Jaoq.)A.DC (4.0g·kg^-1, 8.0g·kg^-1) and MMC at the same time(约0.01). Conclusion Platycodon Grandiflorum(Jaoq.)A.DC can not induce micronulei formation in the mouse bone marrow cells, but showsa protective effect on genetic materials in mice.

Key words: Platycodon Grandiflorum(Jaoq.)A.DC , mitomycin, antimutagenic agents