OBJECTIVE  To study the structure of transformation product of vilmorrianine A by fried processing(oil-bath simulation), and to compare its difference in toxicity and analgesic activity with those of the product under boiled processing.

METHODS  The temperature and time parameters for the frying transformation of vilmorrianine A were screened by HPLC analysis, and the main transformed product was obtained through prepared thin layer chromatography(TLC) and identified by nuclear magnetic resonance(NMR) and mass spectrometry(MS) techniques. The toxicities between the prototypical component and its boiled and fried transformation products were compared through cytotoxicity assay on H9c2 and PC12 cells in vitro, and their analgesic activities were determined by the expression of prodynorphin mRNA on HAPI microglia after drug administration.

RESULTS  The main fried processing product of vilmorrianine A, which was isolated and named pyrovilmorrianine A, could reach the highest content at 180 ℃ for 20 min based on HPLC analysis of the samples under different processing temperatures and times. The results of in vitro cytotoxicity assays indicated that the cardiotoxicity and neurotoxicity of austroconitine B and ezochasmaine, the boiled processing products of vilmorrianine A, decreased sequentially, while the toxicity of the fried product pyrovilmorrianine A was comparable to that of austroconitine B. The results of the analgesic experiment indicated that all the drugs could increase the expression of prodynorphin mRNA in HAPI cells, in which vilmorrianine A and austroconitine B had significant differences compared with normal group(P<0.001), while pyrovilmorrianine A showed remarkable difference(P<0.05).

CONCLUSION  Pyrovilmorrianine A was a main stable transformation product of vilmorrianine A under fried processing, which method could achieve the purpose of toxicity reduction and also retain the analgesic activity partly.