Inhibitory Effects of Dimethyllirioresinol, Epimagnolin A, Eudesmin, Fargesin, and Magnolin on Cytochrome P450 Enzyme Activities in Human Liver Microsomes.

Hyeon-Uk Jeong,Ju-Hyun Kim,Hye Suk Lee,Soon-Sang Kwon

doi:10.3390/ijms18050952

Abstract

Magnolin, epimagnolin A, dimethyllirioresinol, eudesmin, and fargesin are pharmacologically active tetrahydrofurofuranoid lignans found in Flos Magnoliae. The inhibitory potentials of dimethyllirioresinol, epimagnolin A, eudesmin, fargesin, and magnolin on eight major human cytochrome P450 (CYP) enzyme activities in human liver microsomes were evaluated using liquid chromatography-tandem mass spectrometry to determine the inhibition mechanisms and inhibition potency. Fargesin inhibited CYP2C9-catalyzed diclofenac 4′-hydroxylation with a Ki value of 16.3 μM, and it exhibited mechanism-based inhibition of CYP2C19-catalyzed [S]-mephenytoin 4′-hydroxylation (Ki, 3.7 μM; kinact, 0.102 min−1), CYP2C8-catalyzed amodiaquine N-deethylation (Ki, 10.7 μM; kinact, 0.082 min−1), and CYP3A4-catalyzed midazolam 1′-hydroxylation (Ki, 23.0 μM; kinact, 0.050 min−1) in human liver microsomes. Fargesin negligibly inhibited CYP1A2-catalyzed phenacetin O-deethylation, CYP2A6-catalyzed coumarin 7-hydroxylation, CYP2B6-catalyzed bupropion hydroxylation, and CYP2D6-catalyzed bufuralol 1′-hydroxylation at 100 μM in human liver microsomes. Dimethyllirioresinol weakly inhibited CYP2C19 and CYP2C8 with IC50 values of 55.1 and 85.0 μM, respectively, without inhibition of CYP1A2, CYP2A6, CYP2B6, CYP2C9, CYP2D6, and CYP3A4 activities at 100 μM. Epimagnolin A, eudesmin, and magnolin showed no the reversible and time-dependent inhibition of eight major CYP activities at 100 μM in human liver microsomes. These in vitro results suggest that it is necessary to investigate the potentials of in vivo fargesin-drug interaction with CYP2C8, CYP2C9, CYP2C19, and CYP3A4 substrates.

Highlights

Epimagnolin A, dimethyllirioresinol, eudesmin, and fargesin (Figure 1) are the pharmacologically active tetrahydrofurofuranoid lignans found in Flos Magnoliae, Aristolochia elegans rhizomes, and Zanthoxylum armatum DC. [1,2,3,4,5]
The CYP3A4 inactivation potency of fargesin (2.17 min−1 nM−1) was comparable with those reported for some phytochemicals identified as mechanism-based inhibitors of CYP3A4 including aschantin (4.92 min−1 nM−1) [32], bergamottin (2 min−1 nM−1) [42], and rutaecarpine (3.59 min−1 nM−1) [43], but much lower than those reported for podophyllotoxin (13.63 min−1 nM−1) [36], phyllanthin (131.88 min−1 nM−1) and hypophyllanthin (83.21 min−1 nM−1) [35] in human liver microsomes
The incubation mixtures were prepared in total volumes of 100 μL as follows: 50 mM potassium phosphate buffer, 1.0 mM NADPH, 10 mM MgCl2, pooled human liver microsomes (0.2 mg/mL), various concentrations of dimethyllirioresinol, epimagnolin A, eudesmin, fargesin, or magnolin in acetonitrile (final concentrations of 0.1–100 μM, acetonitrile 0.5% (v/v)), and a cocktail of seven cytochrome P450 (CYP) probe substrates (2.0 μM amodiaquine, 5 μM bufuralol, 2.5 μM coumarin, 10 μM diclofenac, 100 μM [S]-mephenytoin, 2.5 μM midazolam, and 50 μM phenacetin, acetonitrile 0.5% (v/v))

Summary

Introduction

Epimagnolin A, dimethyllirioresinol, eudesmin, and fargesin (Figure 1) are the pharmacologically active tetrahydrofurofuranoid lignans found in Flos Magnoliae, Aristolochia elegans rhizomes, and Zanthoxylum armatum DC. [1,2,3,4,5]. Kvai lvuaelsueosf o0f.504.,543,.53,.5a,nadnd2.02.0μμMM, , Fargesin showed mechanism-based inhibition of CYP2C8-catalyzed amodiaquine N-deethylation, CYP2C19-catalyzed [S]-mephenytoin 4 -hydroxylation, and CYP3A4-catalyzed midazolam 1 -hydroxylation in pooled human liver microsomes (Figure 8). The inactivation potency (kinact/Ki ratio) of fargesin against CYP2C19 (27.57 min−1 nM−1) was higher than those of drugs identified as mechanism-based inhibitors of CYP2C19 such as aschantin (8.28 min−1 nM−1), clopidogrel (3.90 min−1 nM−1), and fluoxetine (2.14 min−1 nM−1), but was comparable to that of ticlopidine (22.3 min−1 nM−1) [41] in human liver microsomes. The CYP3A4 inactivation potency (kinact/Ki ratio) of fargesin (2.17 min−1 nM−1) was comparable with those reported for some phytochemicals identified as mechanism-based inhibitors of CYP3A4 including aschantin (4.92 min−1 nM−1) [32], bergamottin (2 min−1 nM−1) [42], and rutaecarpine (3.59 min−1 nM−1) [43], but much lower than those reported for podophyllotoxin (13.63 min−1 nM−1) [36], phyllanthin (131.88 min−1 nM−1) and hypophyllanthin (83.21 min−1 nM−1) [35] in human liver microsomes. The kinact/Ki ratio of fargesin against CYP3A4 was comparable to those of therapeutic drugs known as mechanism-based CYP3A4 inhibitors such as clarithromycin (1–13 min−1 nM−1), erythromycin (3–9 min−1 nM−1), amiodarone (4.5 min−1 nM−1), and fluoxetine (3.2 min−1 nM−1) in human liver microsomes [43]

Materials and Reagents

Kinetic Analysis of CYP2C9 Inhibition by Fargesin

Conclusions