ABSTRACT
Objective: To study the enzymatic reaction kinetics of dl- tetrahydropalmatine (TET) in total alkaloid (TA) of Corydali Rhizoma in rat liver microsomes and to investigate the compatible effects of the effective components such as coumarin (Cou) and volatile oil (VO) in Angelicae Dahuricae Radix with TA in Corydali Rhizoma on enzymatic reaction kinetics of TET. Methods: Rat liver microsomes were prepared by ultracentrifugation and the TET concentration in incubation medium was determined by HPLC. Comparative study on the enzymatic reaction kinetics of TET in each group of TA, TA-Cou, TA-VO, and TA-Cou-VO to deduce the michaelis constant (Km) and maximum reaction rate (Vmax) of TET in each group and calculate the clearance rate (CLint) of TET in each group. Results: The Km, V max, and CLint in TA group were 0.12 μmol/ (L·min·mg), 5.40 μmol/L, and 0.022 L/(min·mg), respectively; In TA-Cou group they were 0.27 μmol/(L·min·mg), 40.18 μmol/L, and 0.006 L/(min·mg), respectively; In TA-VO group they were 0.57 μmol/(L·min·mg), 22.60 μmol/L, and 0.025 L/(min·mg), respectively; In TA-Cou-VO they were 0.84 μmol/(L·min·mg), 23.25 μmol/L, and 0.036 L/(min·mg), respectively. Conclusion: The effective components of TA in Corydali Rhizoma with Cou and VO in Angelicae Dahuricae Radix could decrease CLint of TET in TA of liver.