Abstract: Qualitatively and quantitatively research the extracts of semen strychni before and after frying processing.Data acquisition by UPLC-Q-TOF-MS,and we made qualitative analysis of chemical composition in combination with PeakView software,online database,etc.,used analyst workstation to determine the content of main chemical components,then the ion data before and after processing were imported into SIMCA-P software to establish the OPLS-DA mathematical model to carry out differential secondary metabolite analysis.The results showed that the constituents of semen strychni included alkaloids,glycosides,fatty acids and alcohols,29 of the components were already known,while 13 compounds have not been reported.12 differential biomarkers were identified by OPLS-DA analysis,the most prominent compounds are strychnine,maltose,dattelic acid and oleic acid.Quantitative analysis showed that the content of brucine and strychnine decreased after frying processing,and the reduction of strychnine is slightly larger than brucine,but it still meets the requirements of Pharmacopoeia.We explored the changes in the chemical compositions of semen strychni before and after the frying processing by various means in the study,the results showed that there was a correlation among processing methods,detoxification effect and chemical composition,and provide new ideas and data references for the explanation of the mechanization of semen strychni and the clarification of the pharmacodynamics.

Key words: semen strychni, frying processing, quadrupole time-of-flight mass spectrometry, chemical difference