Ultra-performance liquid chromatography-quadrupole/time-of-flight mass spectrometry analysis of the impact of processing on toxic components of Kansui Radix

Background: Kansui Radix (Gansui in Chinese), the dried tuber of Euphorbia kansui, is a Chinese medicinal herb commonly used for the treatment of oedema and ascites with dyspnea. Because of its toxic nature, the herb is usually processed with vinegar to reduce the toxicity. A report has shown that the contents of toxic terpenoids in Gansui decreased after processing with vinegar. However, comprehensive comparison of the chemical profiles between vinegar-processed and raw Gansui has not yet been conducted. Methods: An ultra-high-performance liquid chromatography in conjunction with ultra-high resolution quadrupole time-of-flight mass spectrometry (UHPLC UHD Q-TOF MS/MS) method was developed for the analysis of chemical profiles of vinegar-processed and raw Gansui in this study. Results: Results showed that processing with vinegar caused conspicuous chemical changes. Among the altered components, 11 toxic terpenoids, 3-O-benzoyl-13-O- dodecanoylingenol/20-O-benzoyl-13-O-dodecanoylingenol, kansuinine D, kansuinine A, 3-O-benzoyl-13-O-dodecanoylingenol/20-O-benzoyl-13-O-dodecanoylingenol, 3-O- benzoylingenol/20-O-benzoylingenol, 20-O-(2'E,4'Z-decadienoyl)ingenol/20-O-(2'E,4'E- decadienoyl)ingenol/3-O-(2'E,4'Z-decadienoyl)ingenol/3-O-(2'E,4'E-decadienoyl)ingenol, 3-O-(2'E,4'Z-decadienoyl)-20-deoxyingenol,3-O-(2'E,4'Z-,ecadienoyl)-5-O-acetylingenol,3-O-(2'E,4'Z-decadienoyl)-20-O-acetylingenol,3-O-(2,3-dimethylbutanoyl)-13-O-dodecanoylingenol, were tentatively identified. The contents of most of these terpenoids were obviously decreased after processing with reductions of 6.66-95.25%. Conclusion: Our findings could help us understand the chemical basis for the toxicity reduction of Gansui afforded by processing with vinegar. Further investigations are warranted to establish the relationship between processing-induced chemical changes and the reduction of toxicity of Gansui.