Effects of Flos carthami on CYP2D6 and on the Pharmacokinetics of Metoprolol in Rats

Effects of safflower injection on the pharmacodynamics and pharmacokinetics of warfarin in rats

1. Safflower injection (SI) is extracted from Chinese herbal medicine safflower that comprises many active components. Warfarin is a common anticoagulant and has exhibited drug interactions with several herbal products. This study aimed to investigate the effects of SI on pharmacodynamics and pharmacokinetics of warfarin in rats. 2. Wistar rats were randomly divided into blank control group, SI group, warfarin control group and SI + warfarin group, respectively. In SI and SI + warfarin groups, rats were injected with SI (1.6 mL/kg/d, i.p.) for 14 days. Warfarin (0.2 mg/kg) was given orally on the eighth day. Saline was given as control. The blood samples were collected at various time points. Prothrombin time (PT) and activated partial thromboplastin time (APTT) were measured. UPLC-MS/MS was used to determine the plasma concentrations of S(R)-warfarin, and the pharmacokinetic parameters were calculated. 3. PT, APTT in SI and SI + warfarin rats increased significantly compared with corresponding control rats. The pharmacokinetic parameters including C_max, t_1/2, AUC_0-t and AUC_0-∞ of S-warfarin and R-warfarin in SI + warfarin rats were higher than those in warfarin control rats. 4. These findings suggest that SI significantly increases the anticoagulant effect of warfarin by affecting its pharmacodynamic and pharmacokinetic parameters.

Effects of eleutheroside B and eleutheroside E on activity of cytochrome P450 in rat liver microsomes

BACKGROUND

Chemicals of herbal products may cause unexpected toxicity or adverse effect by the potential for alteration of the activity of CYP450 when co-administered with other drugs. Eleutherococcus senticosus (ES), has been widely used as a traditional herbal medicine and popular herbal dietary supplements, and often co-administered with many other drugs. The main bioactive constituents of ES were considered to be eleutherosides including eleutheroside B (EB) and eleutheroside E (EE). This study was to investigate the effects of EB and EE on CYP2C9, CYP2D6, CYP2E1 and CYP3A4 in rat liver microsomes in vitro.

METHOD

Probe drugs of tolbutamide (TB), dextromethorphan (DM), chlorzoxazone (CLZ) and testosterone (TS) as well as eleutherosides of different concentrations were added to incubation systems of rat liver microsomes in vitro. After incubation, validated HPLC methods were used to quantify relevant metabolites.

RESULTS

The results suggested that EB and EE exhibited weak inhibition against the activity of CYP2C9 and CYP2E1, but no effects on CYP2D6 and CYP3A4 activity. The IC50 values for EB and EE were calculated to be 193.20 μM and 188.36 μM for CYP2E1, 595.66 μM and 261.82 μM for CYP2C9, respectively. Kinetic analysis showed that inhibitions of CYP2E1 by EB and EE were best fit to mixed-type with Ki value of 183.95 μM and 171.63 μM, respectively.

CONCLUSIONS

These results indicate that EB and EE may inhibit the metabolism of drugs metabolized via CYP2C9 and CYP2E1, and have the potential to increase the toxicity of the drugs.