A new method for the simultaneous analysis of strychnine and brucine in Strychnos nux-vomica unprocessed and processed seeds using a carbon-paste electrode modified with multi-walled carbon nanotubes.

Strychnos nux-vomica L. (Loganiaceae), widely used in folk medicine, is grown extensively in southern Asian countries. Its major bioactive constituents are strychnine and brucine, which are frequently used in traditional herbal medicines for treatment of nervous diseases, vomiting and traumatic pain. A new method using a carbon-paste electrode modified with multi-walled carbon nanotubes (CNT/CPE) was developed and validated for single or simultaneous determination of strychnine and brucine in Strychnos nux-vomica seeds. Additionally, an environmentally friendly method was successfully applied to reduce the levels of strychnine and brucine in seeds. Cyclic voltammetry, chronocoulometry and differential pulse voltammetry were used with multi-walled carbon nanotube modified carbon-paste electrodes. The peak currents increase linearly with the strychnine and brucine concentrations in the ranges of 50-1000 and 5-355 µ m, and the detection limits for strychnine and brucine were 0.43 and 0.28 µ m, respectively. Of the processing methods used, the greatest reduction in the strychnine and brucine levels was observed in samples processed using milk and saltwater. A new, sensitive and selective method was developed for the measurement of strychnine and brucine. This method was successfully applied to the determination of strychnine and brucine in unprocessed and processed Strychnos nux-vomica seed.