Inhibition of human liver cytochrome P450 2D6 (CYP6D2) by tetrahydropalmatine, protopine, and dehydrocorydaline and their oxidative metabolism

= 20.1 µM) and was no longer metabolised by HLMs.These findings indicate that CYP2D6 is a potential target for drug-drug interaction involving THP and PRO, whereas DHC exhibits minimal interaction potential.