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Inhibitory effects of phytochemicals on metabolic capabilities of CYP2D6(*)1 and CYP2D6(*)10 using cell-based models in vitro.

Qu Q, Qu J, Han L, Zhan M, Wu LX, Zhang YW, Zhang W, Zhou HH - Acta Pharmacol. Sin. (2014)

Bottom Line: Herbal products have been widely used, and the safety of herb-drug interactions has aroused intensive concerns.This study aimed to investigate the effects of phytochemicals on the catalytic activities of human CYP2D6(*)1 and CYP2D6(*)10 in vitro.HepG2-CYP2D6(*)1 and HepG2-CYP2D6(*)10 cell lines were successfully constructed.

View Article: PubMed Central - PubMed

Affiliation: 1] Institute of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Xiangya Hospital, Central South University, Changsha 410078, China [2] Xiangya Hospital, Central South University, Changsha 410008, China.

ABSTRACT

Aim: Herbal products have been widely used, and the safety of herb-drug interactions has aroused intensive concerns. This study aimed to investigate the effects of phytochemicals on the catalytic activities of human CYP2D6(*)1 and CYP2D6(*)10 in vitro.

Methods: HepG2 cells were stably transfected with CYP2D6(*)1 and CYP2D6(*)10 expression vectors. The metabolic kinetics of the enzymes was studied using HPLC and fluorimetry.

Results: HepG2-CYP2D6(*)1 and HepG2-CYP2D6(*)10 cell lines were successfully constructed. Among the 63 phytochemicals screened, 6 compounds, including coptisine sulfate, bilobalide, schizandrin B, luteolin, schizandrin A and puerarin, at 100 μmol/L inhibited CYP2D6(*)1- and CYP2D6(*)10-mediated O-demethylation of a coumarin compound AMMC by more than 50%. Furthermore, the inhibition by these compounds was dose-dependent. Eadie-Hofstee plots demonstrated that these compounds competitively inhibited CYP2D6(*)1 and CYP2D6(*)10. However, their Ki values for CYP2D6(*)1 and CYP2D6(*)10 were very close, suggesting that genotype-dependent herb-drug inhibition was similar between the two variants.

Conclusion: Six phytochemicals inhibit CYP2D6(*)1 and CYP2D6(*)10-mediated catalytic activities in a dose-dependent manner in vitro. Thus herbal products containing these phytochemicals may inhibit the in vivo metabolism of co-administered drugs whose primary route of elimination is CYP2D6.

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(A) Effects of quinidine at different concentrations on CYP2D6*1 and *10-mediated AMMC-O-demethylation and bufuralol 1′-hydroxylation. The results are expressed as percentage of control (assayed in the absence of quinidine). (B) Representative Eadie-Hofstee plots for quinidine inhibition of CYP2D6*1 and *10-catalyzed AMMC-O-demethylation and bufuralol 1′-hydroxylation. The substrate AMMC concentration ranged from 0 to 80 μmol/L, whereas the quinidine concentrations used were 0 μmol/L (•), 0.5-fold of the IC50 values (○), and 1-fold of the IC50 values (▾).
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fig3: (A) Effects of quinidine at different concentrations on CYP2D6*1 and *10-mediated AMMC-O-demethylation and bufuralol 1′-hydroxylation. The results are expressed as percentage of control (assayed in the absence of quinidine). (B) Representative Eadie-Hofstee plots for quinidine inhibition of CYP2D6*1 and *10-catalyzed AMMC-O-demethylation and bufuralol 1′-hydroxylation. The substrate AMMC concentration ranged from 0 to 80 μmol/L, whereas the quinidine concentrations used were 0 μmol/L (•), 0.5-fold of the IC50 values (○), and 1-fold of the IC50 values (▾).

Mentions: Quinidine, a well-known inhibitor of CYP2D6, was used as a positive control in the inhibition assay. As shown in Figure 3A, a log-linear decrease in AMMC-O-demethylation and bufuralol 1′-hydroxylation was evident at the concentrations of 1×10−3 to 100 μmol/L. According to the visual inspection of the Eadie-Hofstee plots (Figure 3B), quinidine competitively inhibited CYP2D6*1- and *10-catalyzed AMMC-O-demethylation with Ki values of 0.012 and 0.038 μmol/L, respectively, as well as bufuralol 1′-hydroxylation with Ki values of 0.018 and 0.04 μmol/L, respectively. The ratios of the Ki values of quinidine were 3.315 μmol/L for AMMC and 2.211 μmol/L for bufuralol, showing a higher affinity for CYP2D6*1 than CYP2D6*10. As seen in Table 2, the IC50 values of other compounds were determined and classified as potent, moderate, poor, or no inhibition, in accordance with the previous results17.


Inhibitory effects of phytochemicals on metabolic capabilities of CYP2D6(*)1 and CYP2D6(*)10 using cell-based models in vitro.

Qu Q, Qu J, Han L, Zhan M, Wu LX, Zhang YW, Zhang W, Zhou HH - Acta Pharmacol. Sin. (2014)

(A) Effects of quinidine at different concentrations on CYP2D6*1 and *10-mediated AMMC-O-demethylation and bufuralol 1′-hydroxylation. The results are expressed as percentage of control (assayed in the absence of quinidine). (B) Representative Eadie-Hofstee plots for quinidine inhibition of CYP2D6*1 and *10-catalyzed AMMC-O-demethylation and bufuralol 1′-hydroxylation. The substrate AMMC concentration ranged from 0 to 80 μmol/L, whereas the quinidine concentrations used were 0 μmol/L (•), 0.5-fold of the IC50 values (○), and 1-fold of the IC50 values (▾).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4814035&req=5

fig3: (A) Effects of quinidine at different concentrations on CYP2D6*1 and *10-mediated AMMC-O-demethylation and bufuralol 1′-hydroxylation. The results are expressed as percentage of control (assayed in the absence of quinidine). (B) Representative Eadie-Hofstee plots for quinidine inhibition of CYP2D6*1 and *10-catalyzed AMMC-O-demethylation and bufuralol 1′-hydroxylation. The substrate AMMC concentration ranged from 0 to 80 μmol/L, whereas the quinidine concentrations used were 0 μmol/L (•), 0.5-fold of the IC50 values (○), and 1-fold of the IC50 values (▾).
Mentions: Quinidine, a well-known inhibitor of CYP2D6, was used as a positive control in the inhibition assay. As shown in Figure 3A, a log-linear decrease in AMMC-O-demethylation and bufuralol 1′-hydroxylation was evident at the concentrations of 1×10−3 to 100 μmol/L. According to the visual inspection of the Eadie-Hofstee plots (Figure 3B), quinidine competitively inhibited CYP2D6*1- and *10-catalyzed AMMC-O-demethylation with Ki values of 0.012 and 0.038 μmol/L, respectively, as well as bufuralol 1′-hydroxylation with Ki values of 0.018 and 0.04 μmol/L, respectively. The ratios of the Ki values of quinidine were 3.315 μmol/L for AMMC and 2.211 μmol/L for bufuralol, showing a higher affinity for CYP2D6*1 than CYP2D6*10. As seen in Table 2, the IC50 values of other compounds were determined and classified as potent, moderate, poor, or no inhibition, in accordance with the previous results17.

Bottom Line: Herbal products have been widely used, and the safety of herb-drug interactions has aroused intensive concerns.This study aimed to investigate the effects of phytochemicals on the catalytic activities of human CYP2D6(*)1 and CYP2D6(*)10 in vitro.HepG2-CYP2D6(*)1 and HepG2-CYP2D6(*)10 cell lines were successfully constructed.

View Article: PubMed Central - PubMed

Affiliation: 1] Institute of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Xiangya Hospital, Central South University, Changsha 410078, China [2] Xiangya Hospital, Central South University, Changsha 410008, China.

ABSTRACT

Aim: Herbal products have been widely used, and the safety of herb-drug interactions has aroused intensive concerns. This study aimed to investigate the effects of phytochemicals on the catalytic activities of human CYP2D6(*)1 and CYP2D6(*)10 in vitro.

Methods: HepG2 cells were stably transfected with CYP2D6(*)1 and CYP2D6(*)10 expression vectors. The metabolic kinetics of the enzymes was studied using HPLC and fluorimetry.

Results: HepG2-CYP2D6(*)1 and HepG2-CYP2D6(*)10 cell lines were successfully constructed. Among the 63 phytochemicals screened, 6 compounds, including coptisine sulfate, bilobalide, schizandrin B, luteolin, schizandrin A and puerarin, at 100 μmol/L inhibited CYP2D6(*)1- and CYP2D6(*)10-mediated O-demethylation of a coumarin compound AMMC by more than 50%. Furthermore, the inhibition by these compounds was dose-dependent. Eadie-Hofstee plots demonstrated that these compounds competitively inhibited CYP2D6(*)1 and CYP2D6(*)10. However, their Ki values for CYP2D6(*)1 and CYP2D6(*)10 were very close, suggesting that genotype-dependent herb-drug inhibition was similar between the two variants.

Conclusion: Six phytochemicals inhibit CYP2D6(*)1 and CYP2D6(*)10-mediated catalytic activities in a dose-dependent manner in vitro. Thus herbal products containing these phytochemicals may inhibit the in vivo metabolism of co-administered drugs whose primary route of elimination is CYP2D6.

Show MeSH
Related in: MedlinePlus