Interaction between Red Yeast Rice and CYP450 Enzymes/P-Glycoprotein and Its Implication for the Clinical Pharmacokinetics of Lovastatin

Table 2

Inhibitory potencies of extracts of RYR products or pure lovastatin on the activities of different CYP450 enzymes in human liver microsomes.

IC50 (μM)	Pure lovastatin	LipoCol Forte	Xuezhikang	Cholestin	Specific CYP inhibitor*
CYP1A2	>100 μM	5.21 ± 0.15^a	2.45 ± 0.32^a,b	7.26 ± 0.39^a	3.11 ± 0.36
CYP2B6	14.96 ± 1.11	2.49 ± 0.40^a	3.48 ± 0.38^a	5.45 ± 0.53^a	0.48 ± 0.07
CYP2C9	16.87 ± 3.25	1.85 ± 0.17^a	2.49 ± 0.10^a	3.93 ± 0.35^a	0.152 ± 0.001
CYP2C19	9.85 ± 1.20	1.52 ± 0.48^a,b	2.67 ± 0.82^a,b	1.62 ± 0.09^a,b	2.49 ± 1.01
CYP2D6	>50 μM	3.97 ± 1.33^a	5.52 ± 0.98^a	7.26 ± 2.70^a	0.44 ± 0.19
CYP3A4	14.04 ± 1.21	3.13 ± 0.18^a	1.72 ± 0.13^a	8.26 ± 0.44^a	0.062 ± 0.002

The data are the mean ± SEM for three to four separate preparations.
*The specific inhibitors were furafylline for CYP1A2, ticlopidine for CYP2B6 and CYP2C19, sulfaphenazole for CYP2C9, quinidine for CYP2D6, and ketoconazole for CYP3A4.
^aP value < 0.05 compared to pure lovastatin; ^bP value > 0.05 compared to the specific inhibitor for each enzyme.