Metabolic profiling of senkyunolide A and identification of the metabolite in hepatocytes by ultra-high performance liquid chromatography combined with diode array detector and high resolution mass spectrometry

Rationale: Senkyunolide A is one of the bioactive constituents originally isolated from Ligusticum chuanxiong Hort. To better understand the action of this constituent, it is necessary to study the metabolic profiles in different species.

Methods: For metabolic stability study, senkyunolide A at a concentration of 0.5 μM was individually incubated with hepatocytes of mouse, rat, dog, monkey and human at 37 ^o C for 2 h. For metabolite profiling and identification, senkyunolide A (10 μM) was incubated with hepatocytes and the incubation samples were analyzed by ultra-high performance liquid chromatography combined with diode array detector and high resolution mass spectrometry (UHPLC-DAD-HRMS). The identities of the metabolites were characterized by accurate masses, product ions and retention times.

Results: Senkyunolide A was metabolically instability in hepatocytes. The in vitro half-lives were 136.2, 60.6, 33.65, 55.96 and 138 min in mouse, rat, dog, monkey and human hepatocytes, respectively. Furthermore, a total of 14 metabolites were detected. M1 and M9 were the most abundant metabolites in all species. The metabolic pathways of senkyunolide A involved the following pathways: 1) hydroxylation to form 10- and 11-hydroxyl-senkyunolide A, which further underwent epoxidation followed by GSH conjugation; 2) epoxidation followed by epoxide hydrolysis or GSH conjugation; and 3) aromatization to form 3-butylphthalide followed by hydroxylation.

Conclusions: Hydroxylation, epoxidation, aromatization and GSH conjugation were the main metabolic pathways of senkyunolide A. This study provides an overview of the metabolic profiles of senkyunolide A, which is helpful for us to understand the action of this compound.