Rhodionin, isolated from the root of Rhodiola crenulata , is a specific non-competitive cytochrome P450 2D6 inhibitor with an IC 50 of 0.761 μM and a Ki of 0.769 μM Rhodionin exhibits potent, dose-dependent inhibitory effects on acetylcholinesterase (AChE) with IC 50 ranged from 57.50 to 2.43 μg/mL Rhodionin exhibits potent DPPH free radical scavenging activities, with an IC 50 of 19.49 μM