Original Article

Herbal medicine Yin Zhi Huang induces CYP3A4-mediated sulfoxidation and CYP2C19-dependent hydroxylation of omeprazole

Lan Fan, Guo Wang, Lian-sheng Wang, Yao Chen, Wei Zhang, Yuan-fei Huang, Rui-xue Huang, Dong-li Hu, Dan Wang, Hong-hao Zhou

Abstract

Aim: To explore the potential interactions between Yin Zhi Huang (YZH) and omeprazole, a substrate of CYP3A4 and CYP2C19.
Methods: Eighteen healthy volunteers, including 6 CYP2C19*1/*1, 6 CYP2C19*1/*2 or *3 and 6 CYP2C19*2/*2 were enrolled in a 2-phase, randomized, crossover clinical trial. In each phase, the volunteers received either placebo or 10 mL YZH oral liquid, 3 times daily for 14 d. Then all the patients took a 20 mg omeprazole capsule orally. Blood samples were collected up to 12 h after omeprazole administration. Plasma concentrations of omeprazole and its metabolites were quantified by HPLC with UV detection.
Results: After 14 d of treatment of YZH, plasma omeprazole significantly decreased and those of omeprazole sulfone and 5-hydroxyomeprazole significantly increased. The ratios of the area under the plasma concentration-time curves from time 0 to infinity (AUC(0-infinity) of omeprazole to 5-hydroxyomprazole and those of omeprazole to omeprazole sulfone decreased by 64.80%plusminus12.51% (P=0.001) and 63.31%plusminus18.45% (P=0.004) in CYP2C19*1/*1, 57.98%plusminus14.80% (P=0.002) and 54.87%plusminus18.42% (P =0.003) in CYP2C19*1/*2 or *3, and 37.74%plusminus16.07% (P=0.004) and 45.16%plusminus15.54% (P=0.003) in CYP2C19*2/*2, respectively. The decrease of the AUC(0-infinity) ratio of omeprazole to 5-hydroxyomprazole in CYP2C19*1/*1 and CYP2C19*1/*2 or *3 was greater than those in CYP2C19*2/*2 (P=0.047 and P=0.009).
Conclusion: YZH induces both CYP3A4-catalyzed sulfoxidation and CYP2C19-dependent hydroxylation of omeprazole leading to decreases in plasma omeprazole concentrations.
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