Different AhR binding sites of diterpenoid ligands from Andrographis paniculata caused differential CYP1A1 induction in primary culture in mouse hepatocytes

► Diterpenoids from Andrographis paniculata modulated BNF-induced CYP1A1 mRNA expression. ► Molecular docking results were consistent with the CYP1A1 mRNA expressions. ► In the presence of different diterpenoids, BNF bound to different AhR-regions. ► Different AhR-binding region of BNF is a key factor for the CYP1A1 expression.