A simple method to identify the unprocessed Strychnos seeds used in herbal medicinal products

Simon Quan-Bin Han, Song Lin Li, Chun Feng Qiao, Jing Zheng Song, Zongwei Cai, Paul Pui Hay But, Pang Chui Shaw, Hong Xi Xu*

*Corresponding author for this work

Research output: Contribution to journalJournal articlepeer-review

14 Citations (Scopus)


The seeds of Strychnos nux-vomica are popularly used in the treatment of arthritis. Being extremely toxic, the raw seeds are forbidden and must be processed before clinical use. The quality of crude and processed Strychnos seeds can be controlled by examining the toxic alkaloids using established HPLC methods. But this procedure does not work in the case where the seeds are powdered and mixed with other medicinal materials in proprietary production. In this quality control study on Strychnos seeds, the contents of two major toxic alkaloids (strychnine and brucine) and a major non-alkaloid constituent (loganic acid) in twenty-four samples of Strychnos seeds (nine processed and fifteen unprocessed) were compared using published HPLC-UV methods. The resuits showed that the better the seeds were processed, the less loganic acid was found. The alkaloids and non-alkaloid components simultaneously decreased in processed seeds. The content ratio between alkaloids and loganic acid was clearly different in well-processed and crude Strychnos seeds. Based on this interesting discovery, a simple chromatographic method was established which allows a simultaneous determination of loganic acid and the alkaloids strychnine and brucine. The relative peak area (RPA) of strychnine-to-loganic acid was revealed to be a reliable key quality control parameter in order to effectively identify the processed seeds. This new method has been successfully applied to detect the insufficiently processed Strychnos material in marketed herbal medicinal products.

Original languageEnglish
Pages (from-to)458-463
Number of pages6
JournalPlanta Medica
Issue number4
Publication statusPublished - Mar 2008

Scopus Subject Areas

  • Analytical Chemistry
  • Molecular Medicine
  • Pharmacology
  • Pharmaceutical Science
  • Drug Discovery
  • Complementary and alternative medicine
  • Organic Chemistry

User-Defined Keywords

  • Loganiaceae
  • Loganic acid
  • Relative peak area
  • Strychnine
  • Strychnos nux-vomica


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