OBJECTIVE  To establish the acute toxicity evaluation of the roots, stems and leaves in mice and quantitative determination method of 8 chemical components in Euchresta japonica, and preliminarily speculate the potential toxic components.

METHODS  The acute toxicity test was performed by gavage of 95% ethanol extracts of roots, stems and leaves of Euchresta japonica into mice with blank and five dose groups, and the groups were set by the preliminary experiment of the minimum dose cause 100% death and the maximum dose cause 0% death. The modified Kohl's method was used to calculate LD₅₀ and 95% confidence limits; the biochemical indexes, organ indices and body weight changes of mice with maximum tolerance were detected to evaluate the acute toxicity. The contents of 6 alkaloids and 2 flavonoids were determined by HPLC. The correlation coefficient between 8 chemical components with LD₅₀ was calculated by Pearson's method.

RESULTS  The LD₅₀ of the roots, stems and leaves of Euchresta japonica were 11.969, 11.866 and 15.601 g∙kg⁻¹, respectively; the concentration of alanine aminotransferase, aspartate aminotransferase and creatinine in the blood of mice in the root, stem and leaf groups were significantly increased under the maximum non-lethal concentration (P<0.05 or P<0.01), while the blood urea nitrogen in the root and leaf groups had no significant change. The blood urea nitrogen level in the stem group was significantly increased (P<0.05). The peak area and mass concentration of the 8 components had linear relationship with the coefficient of determination R²>0.990, of which the correlation coefficient between the content of (−)-cytisine(H3) and the LD₅₀ value was −0.985.

CONCLUSION  The roots, stems and leaves extracts of Euchresta japonica can cause liver and kidney damage, have showed obvious acute oral toxicity, the roots and stems are more toxic than the leaves, and the potential toxic component is (−)-cytisine.