Abstract: ObjectiveTo study the influence of water precipitating on alcohol extracts from Herba Leonuri for acute toxicity and damage degree of toxicity target organs in mice. MethodsUV spectrophotometry was used to measure the content of total alkaloids and the method of acute toxicity was used to compare the difference of acute toxicity between different alcohol extraction processes, and its toxic symptoms, cumulative mortality and weight change in mice were recorded. Seven days after administration, blood was taken, the contents of serum biochemical indicators were detected, livers and kidneys were taken for organ coefficient. ResultsThe contents of total alkaloids in the alcohol extracts and water precipitated alcohol extracts of Herba Leonuri were separately 0.82% and 0.65%. The LD50 of alcohol extracts from Herba Leonuri is 118.68 g·kg-1, which is equal to 276.9 times of human daily dried medicinal herb dose. The 95% confidence interval is 112.84~124.89 g·kg-1, which is equal to 263.3~291.4 times of human daily dried medicinal herb dose. The MLD of water precipitated alcohol extracts from Herba Leonuri is 433.20 g·kg-1, which is equal to 1 010.8 times of human daily dried medicinal herb dose. The alcohol extracts and water precipitated alcohol extracts of Herba Leonuri all could lead to significant increase (P <0.001) of mice's BUN and Cr levels. Compared with normal control group, kidney coefficient increased significantly, and the statistical tests showed varying degree difference. Compared with water precipitated alcohol extracts of Herba Leonuri, the BUN and Cr levels increased in group 1~4 of alcohol extracts, and the statistical tests showed varying degree difference. Kidney coefficient increased significantly, and the statistical tests showed varying degree difference. The group 1~2 of alcohol extracts and water precipitated alcohol extracts from Herba Leonuri could result in increased ALT and AST. Compared with normal control group, the statistical tests showed the varying degree difference. Group 1 of alcohol extracts could lead to liver coefficient increase which showed very significant difference (P <0.01). Compared with water precipitated alcohol extracts of Herba Leonuri, the ALT and AST levels and liver coefficient in group 1~2 of alcohol extracts increased. The statistical tests showed the varying degree difference. Liver and kidney pathology showed that there were no obvious pathological changes in liver and kidney tissues in mice. ConclusionAcute toxicity test showed that the toxicity target organs of Herba Leonuri were mainly kidney and liver. It proved that BUN and Cr levels significantly increased, ALT and AST levels increased, liver and kidney coefficients increased. The toxicity of kidney was higher than that of liver, and the toxicity of alcohol extract is higher than that of water precipitated alcohol extract. Combined with assay data of alcohol extract and water precipitated alcohol extract from Herba Leonuri, it is suggested that the toxicity of Herba Leonuri's extracts and total alkaloids content showed a certain correlation. Alcohol extracts with water precipitating can reduce toxicity significantly and the content of total alkaloids. Maybe water precipitating can remove the lipid soluble impurities which is also the toxic components of Herba Leonuri. But the specific toxic substances need to be further studied.

Key words: Herba Leonuri, water precipitating, alcohol extract, acute toxicity, toxicity target organ