New understanding of aconitine hydrolysis pathway: Isolation,identification and toxicity evaluation based on intermediate products

Aconitine hydrolysis is deemed to be the guarantee for the safe application of Aconitum phytomedicine. Studies have suggested that hydrolysates of aconitine not only include benzoylaconitine and aconine, but other hydrolysates. Moreover, these hydrolysates maybe have a mutual transformation relationship, which has not been confirmed. Herein, hydrolysates of aconitine and their mutual transformation relationship were studied by the theoretical quantum chemistry, UPLC-Q-TOF-MS, the separation and identification of target products, etc. Then the toxicity of its hydrolysates was evaluated. The results demonstrate that the probability is the same for aconitine hydrolysis to pyroaconitine and benzoylaconitine, but they are difficult to convert to each other. Aconitine hydrolysis has three independent hydrolysis pathways, 1) to indaconitine, 2) to benzoylaconitine, and aconine, 3) to pyroaconitine and to 16-epi-pyroaconine. The result of embryotoxicity evaluation on zebrafish was aconitine > indaconitine > benzoylaconitine > α-pyroaconitine > β- pyroaconitine > aconine > 16-epi-pyroaconine. In conclusion, aconitine have three independent hydrolysis pathways and the hydrolysates of different pathways cannot be transformed into each other. Pyroaconitine is a hydrolysate of aconitine except for benzoylaconitine, and its toxicity is lower than benzoylaconitine. More importantly, it clarifies the long-standing debate and provides scientific evidence for the processing and detoxification of Aconitum phytomedicine.