二氢白屈菜红碱在不同溶剂的结构转化研究

Study on structural conversion of dihydrochelerythrine in different solvents

利用色谱分离和重结晶法从延胡索乙醇提取物中分离得到二氢白屈菜红碱，并且首次发现其性质不稳定。运用NMR，HPLC，LC-MS等技术发现二氢白屈菜红碱在极性氘代试剂中（如DMSO-d6和MeOD）会缓慢直接转化为白屈菜红碱；在低极性氘代试剂（CD2Cl2）中，除了白屈菜红碱，还会产生假碱和二聚体中间体，最终被氧化为氧化白屈菜红碱。结构转化原因可能是由于氢白屈菜红碱中C-6位对亲核试剂的高度敏感性，在不同溶剂中容易被氧化为不同的产物。研究结果为含有二氢白屈菜红碱及其类似衍生物药材的提取分离、活性筛选和质量评价提供依据。

Dihydrochelerythrine was isolated from the ethanol extract of Corydalis yanhusuo by chromatographic and recrystallization techniques. To our knowledge, this is the first report that dihydrochelerythrine was found to be unstable. The NMR, HPLC, and LC-MS were applied to monitor the structural conversion process of dihydrochelerythrine. The results showed that when dissolved in polar deuteration solvent （e.g.,DMSO-d6 ＆ MeOD）, dihydrochelerythrine is directly converted to chelerythrine gradually. However, if used non-polar reagent （e.g. , CD2Cl2 ）, the sample of dihydrochelerythrine undergoes the formation of pseudobase, chelerythrine, and bimolecular ether then followed by oxidation to oxychelerythrine as the major final product. Which leads to this phenomenon maybe is that the C-6 in dihydrochelerythrine is highly reactive to nucleophiles, and is easily converted to different derivatives in different solvents attributed to the solvent effect. This finding will contribute to the extraction and isolation, bioactivity screening, and quality evaluation of medicinal materials containing dihydrochelerythrine and other similar derivatives.