Research Article
Inhibition of Cytochrome P450 Activities by Sophora flavescens Extract and Its Prenylated Flavonoids in Human Liver Microsomes
Figure 5
Concentration- and time-dependent inactivation of human liver microsomal CYP3A4 by S. flavescens extract (a) and kushenol I (b) and recombinant CYP3A4 by kushenol I (c) in the presence of an NADPH-generating system. The logarithm of the percentage of remaining activity (related to time 0 in the presence of solvent alone) was plotted as a function of time; the corresponding double reciprocal plots for the inactivation rate and the concentration of S. flavescens extract or kushenol I are shown. The Ki and kinact values were obtained from the reciprocals of the x- and y-intercepts, respectively. Each data point represents the mean of duplicate experiments.
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