Simultaneous assessment of absorption characteristics of coumarins from Angelicae Pubescentis Radix: In vitro transport across Caco-2 cell and in vivo pharmacokinetics in rats after oral administration

Angelicae Pubescentis Radix (APR), a well-known traditional Chinese medicine, is widely used for the treatments of rheumatism and headache for centuries. To assess the absorption characteristics of coumarins from APR, a sensitive and reliable UPLC-MS/MS method was established for the simultaneous determination of sixteen coumarins from APR, including psoralen, xanthotoxin, bergapten, bergaptol, isoimperatorin, imperatorin, columbianetin, columbianetin acetate, columbianadin, oxypeucedanin hydrate, angelol B, umbelliferone, scopoletin, osthole, meranzin hydrate and nodakenetin. The specificity, linearity, sensitivity, precision, accuracy, recovery, matrix effect and stability of the method were all validated to be satisfactory. The method was then applied to the in vitro transport of APR extract (APRE) across human intestinal epithelial Caco-2 cell and in vivo pharmacokinetics in rats after oral administration of APRE. All of the tested coumarins were well or moderately absorbed across Caco-2 monolayers, and could be quickly absorbed into rat blood circulation after oral administration. Columbianetin was the most easily absorbed compound across Caco-2 cell, and also had extremely highest plasma concentration in vivo. Excellent correlation between in vitro absorption across Caco-2 cell monolayers and in vivo pharmacokinetics of coumarins from APRE was well verified. The results provided valuable information for the overall absorption characteristics of the coumarins from APR, as well as for its further studies of in vivo active substances in the further.