Objective: To test whether 7 herbs stimulate human pregnane X receptor (PXR)-mediated CYP3A4 transcription.
Method: Transient cotransfection reporter gene assays were performed with human PXR expression plasmids and a reporter plasmid containing the XRES in the CYP3A4 gene promoter in HepG2 cells.
Result: The aqueous extracts of Chrysanthemi Flos, Lycii Fructus, and Salviae Miltiorrhizae Radix et Rhizoma, and the methanol extracts of Chrysanthemi Flos, Crataegi Fructus, Lycii Fructus, Lonicerae Japonicae Flos, Dioscoreae Rhizoma,and Salviae Miltiorrhizae Radix et Rhizoma, activated human PXR-mediated transcription.
Conclusion: The aqueous extracts of Chrysanthemi Flos, Lycii Fructus, and Salviae Miltiorrhizae Radix et Rhizoma, and the methanol extracts of Chrysanthemi Flos, Crataegi Fructus, Lycii Fructus, Lonicerae Japonicae Flos, Dioscoreae Rhizoma, and Salviae Miltiorrhizae Radix et Rhizoma are inducers of CYP3A4 by activating PXR, and thus may influence the metabolism of other substrates on CYP3A4.