Background:
Schisandrin A inhibits CYP3A activity with an IC50 of 6.60 μM and Ki of 5.83 μM, respectively.
Schisandrin A (Sch A) strongly inhibits microsomal midazolam 1-hydroxylation catalyzed by CYP3A, with an IC50 of 6.60 μM. The recovery of enzyme activity in the absence or presence of Schisandrin A is shown in dilution assay plots. The Ki value for Schisandrin A is obtained from the Dixon plots and is 5.83 μM. The inactivation of rat liver microsomal midazolam 1-hydroxylation activity by Schisandrin A in the presence of NADPH is found to be time- and concentration-dependent. The Kinact and Ki are estimated to be 0.134/min and 4.51 μM, respectively for Schisandrin A[1].
Schisandrin A (SchA) significantly inhibits CYP3A activity in rat hepatic microsomes and Vmax value of each group in a concentration-dependent manner. The double-reciprocal plots and the secondary plot show that Schisandrin A inhibits CYP3A activity, with an apparent Ki value of 30.67 mg/kg. In each Schisandrin A-treated group, Schisandrin A also significantly decreases 1-hydroxymidazolam plasma concentrations compared with the negative group (to levels similar to the positive group)[2].
参考文献:
[1]. Li WL, et al. Inhibitory effects of Schisandrin A and Schisandrin B on CYP3A activity. Methods Find Exp Clin Pharmacol. 2010 Apr;32(3):163-9.
[2]. Li WL, et al. Inhibitory effects of continuous ingestion of Schisandrin A on CYP3A in the rat. Basic Clin Pharmacol Toxicol. 2012 Feb;110(2):187-92.
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