目的 研究滇乌碱在砂炒过程中的结构转化途径，比较滇乌碱与转化产物的急性毒性和转化产物的抗心律失常活性。方法 采用HPLC法筛选出滇乌碱发生结构转化的温度和时间参数，通过柱色谱法和核磁共振（nuclear magnetic resonance，NMR）、质谱（mass spectrometry，MS）技术，分离鉴定出滇乌碱的砂炒转化产物；采用急性毒性实验比较原型成分和转化产物的毒性强弱；采用乌头碱建立大鼠心律失常模型，明确转化产物的抗心律失常作用。结果 通过比较不同炮制温度、时间样品的HPLC色谱图，筛选出滇乌碱在140～180℃，加热5～30 min时发生结构转化；分离、鉴定出滇乌碱的砂炒产物pyroyunaconitine；急性毒性实验结果表明，滇乌碱的半数致死量（lethal dose 50%，LD₅₀）为0.353 mg/kg，pyroyunaconitine的LD₅₀为62.563 mg/kg，炮制后毒性明显降低。抗心律失常实验结果显示，随着炮制产物pyroyunaconitine剂量的增大，大鼠的室性早搏（ventricular premature beat，VPB）潜伏期延长，室性心动过速（ventricular tachycardia，VT）发生率降低，心律失常完全抑制率逐渐升高，呈剂量相关性，表明其有一定的抗心律失常作用。结论 砂炒过程中，滇乌碱的C-8位脱去乙酰基，生成去8-去乙酰滇乌碱；接着，8-去乙酰滇乌碱的C-8位和C-15位之间脱水形成双键，生成pyroyunaconitine；pyroyunaconitine的毒性远低于原型成分滇乌碱，并具有一定的抗心律失常活性。

Objective To study the structural transformation pathway of yunaconitine during the stir-frying process with sand, and compare the acute toxicity and antiarrhythmic activity of yunaconitine with its processing products. Methods Using HPLC to screen out the temperature and time parameters of the structural transformation of yunaconitine; The processing products of yunaconitine were separated and identified using column chromatography, nuclear magnetic resonance (NMR) and mass spectrometry (MS); The acute toxicity test was performed to compare the toxicity of yunaconitine with its processing products; The aconitine-induced arrhythmia model was used to clarify the activity of the processing products. Results Yunaconitine was converted into pyroyunaconitine when it was heated at 140-180℃ for 5-30 min. The acute toxicity test results showed that the lethal dose 50% (LD₅₀) of yunaconitine and pyroyunaconitine were 0.353 mg/kg and 62.563 mg/kg, respectively. The toxicity of yunaconitine was significantly reduced after processing. In the antiarrhythmic assay, the pyroyunaconitine could delay the onset time of ventricular premature beat (VPB), reduce the incidence of ventricular tachycardia (VT) and increase arrhythmia inhibition rate with increasing dose. The result indicated that pyroyunaconitine dose-dependently exhibited antiarrhythmic activities. Conclusion The structural transformation pathway of yunaconitine has been defined:The acetoxyl group at C-8 of yunaconitine was firstly hydrolyzed to a hydroxyl group, and then a double bond was subsequently introduced at C-8/C-15 via further dehydration, resulting in the formation of pyroyunaconitine. Compared with yunaconitine, the toxicity of pyroyunaconitine was reduced. And it possesses specific antiarrhythmic properties.

R283.6

四川省科技计划项目（2020YJ0131）；成都中医药大学“杏林学者”学科人才科研提升计划（QJRC2022046）