Abstract: Objective To discuss the effect of refining process on the content and acute toxicity of Bupleurum saikosaponin substances and to determine the main toxical substance basis of Bupleurum by comparing the type of resins and the elution chromatography, as well as the concentration of elution solvent. Methods To determine the content of saikosaponin a and the acute toxicity of different refining process on the total Bupleurum Saikosaponin in accordance with HPLC method and the classical acute toxicity test methods. Results Calculated by the content of saikosaponin a, we found that the type of macro porous resin D101 and the 70% alcohol elutropic fraction is the better refining process. The effect of acute toxicity is 70% alcohol elutropic fraction> 50% alcohol elutropic fraction>30% alcohol fraction>80% alcohol elutropic fraction>water elutropic fraction>95% alcohol elutropic fraction. Conclusion There are significant differences on the contents of saikosaponin a and the toxicity, and there is some relevance between the toxicity and the Bupleurum saikosaponin substances content. We found that the best refining process of enriching the Bupleurum saikosaponin is using the macroporous resin D101 and the 70% alcohol elutropic fraction.

Key words: Bupleurum saikosaponin, the refining process, mice, acute toxicity