ABSTRACT
Objective To establish the method for the determination of the content of total alkaloids extracted from seeds of Strychnos nux-vomica L. Methods The content of total alkaloids in the samples was determined by the acid dye colorimetry, which was performed with brucine and strychnine as the reference substances, dibromothymolsulfonphthalein as the acidic dye under the condition of a buffer solution (pH=7.2), and chloroform was used as the extractant. Results Both the concentration of brucine being 0.041 2～ 0.206 mg/mL and that of strychnine being 0.042 8～ 0.214 mg/mL had a good linear relationship with the absorbance. The average recoveries for brucine and strychnine were (101.8? 4.6) % and (103.3? 2.7) % , respectively. Conclusion The established method is simple, accurate and stable, and can be used for the determination of the content of the total alkaloids extracted from the seeds of Strychnos nux-vomica L.