Abstract: Ligustilide is one of main active components from Rhizoma Chuanxiong and Radix Angelicae Sinensis. However, the instability of ligustilide limits its further research and application in clinics.In this study,the transformation products of ligustilide were prepared,after one month at room temperature,by conventional chromatography and spectroscopic methods.Fourteen transformation products were obtained and elucidated,which included a new dimerphthalide,namely,7′-carboxyl-wallichilide (1).The relative contents of ligustilide and its fourteen transformation products were determined by area normalization using LC-MS.The results showed that ligustilide dimers were the main transformation products of ligustilide.

Key words: ligustilide, stability, transformation products