Abstract: Objective To investigate the acute toxicity of 5-hydroxymethylfurfural(5-HMF) on ICR mice and cytotoxicity on mast cell RBL-2H3 and P815. Methods ICR mice received tail vein injection of 8 different doses of 5-HMF. The mice were observed daily to record the number of death and body weight, then 50 % lethal dose of (LD₅₀) was counted. Pathological examination was completed at the end of the observation period. The cytotoxicity of 5-HMF on mast cell: RBL-2H3 and P815 was measured by MTT assay and 50 % inhibitory concentration (IC₅₀) was calculated. Results Ataxia, tonic convulsions and other phenomena appeared in low doses, and with the dose increasing the frequency of above phenomenon increased. 5-HMF significantly decreased the weight of all groups from d1~d14 compared with control group(P <0.01) and the LD₅₀ value was 871.12 mg·kg^-1 using Bliss method based on the mortality rate. Pathological examination showed that mice had chronic progressive nephropathy in all doses. The IC₅₀ of 5-HMF solution on RBL-2H3 and P815 was respectively 4.96 mM and 7.43 mM. Conclusion 5-HMF has acute toxicity with LD₅₀ 871.12 mg·kg^-1, and kidney is the toxic target organ. IC₅₀ in RBL-2H3 and P815 is 4.96 mM and 7.43 mM respectively. It provided the experimental basis for the degranulation of mast cells and theoretical basis for its quality control and further safety research.

Key words: 5-hydroxymethylfurfural(5-HMF), acute toxicity, cytotoxicity, mast cell