Characterization of the metabolites of dichotomitin in rat, monkey and human by ultra-high-performance liquid chromatography/high-resolution mass spectrometry.

Rationale: Dichotomitin is one of the bioactive constituents isolated from Belamcanda chinensis. The goal of this study was to identify the metabolites of dichotomitin produced by liver microsomes and hepatocytes.

Methods: Using ultra-high-performance liquid chromatography and high-resolution mass spectrometry (UPLC/HRMS), the metabolites were profiled and identified. The exact masses, elemental compositions and product ions of the metabolites were used to characterize their structures.

Results: A total of ten metabolites were found and identified. The main metabolites identified in the incubation samples were M6 (3',5,6,7-tetrahydroxy-4',5'-dimethoxyisoflavone) and M8 (8-hydroxydichotomitin). Opening of 1,3-benzodioxole, demethylation, hydroxylation, glucuronidation and sulfation were among the metabolic modifications for dichotomitin. A human recombinant cytochrome P450 enzyme study revealed that CYP 1A2, 2C19, and 2D6 facilitated the formation of M6, whereas CYP 1A2 catalyzed the formation of M8 exclusively.

Conclusions: For the first time, data on the in vitro metabolic fates of dichotomitin were revealed in this work which would be helpful for us to understand the disposition of this bioactive constituent.