Abstract: OBJECTIVE: To investigate the toxicity of polyoxometalates α_K8H2[SiW9Ti3O40]·15H2O(α_Ti3) for clinic application. METHODS: The studies were conducted with acute toxicity test, cumulative toxicity test, Ames test and chromosome aberration test on CHO cell in vitro and cytotoxicity test. RESULTS: LD50 in mice was 2 055.36 mg/kg, α_Ti3 was a low_grade toxicity compound. The cumulation coefficient was exceed 5, it showed α_Ti3 was low cumulation. The results of Ames test showed no mutagenic effects with the concentration ranged from 31.3 to 500 μg/utensil with or without S9 mixture added. The chromosome aberration ratio of α_Ti3 groups was no significant discrepancy compared with the control on CHO cells,with the concentration ranged from 40 to 320 μg/ml with or without S9 mixture added. IC50 of medulla cells and peripheral blood lymphocytes of rats in vitro treated with α_Ti3 were 0.223 and 0.135 mg/ml,respectively. However,IC50 of S180 ascites tumor cell and mice hepatoma carcinoma cell were low. It showed the toxicity of α_Ti3 was low on normal cell. CONCLUSION: The toxicity of α_Ti3 was low and no mutagenicity was observed in this experiment,the results suggested that α_Ti3 should be a better anti_tumor drug in clinic chemical theropy.

Key words: polyoxometalates, acute toxicity, cumulative toxicity, mutagenicity test, cytotoxicity