Figure 3

Inhibition of activities of CYP isoforms by PBQs 1 (A) and PBQ2 (B). Human recombinant CYP1B1-catalyzed dealkylation of ERes (0.37 μM), CYP1A1, CYP1A2, and CYP2C19-catalyzed dealkylation of CEC (0.5, 5, and 25 μM, respectively) CYP2D6-catalyzed dealkylation of AMMC (1.5 μM) and CYP3A4-catalyzed debenzylation of BFC (50 μM) were determined in the presence of varying concentrations of PBQs ranging between 0 and 900 μM, as described in the section “methods”. Control enzyme activity (mean ± SEM) for CYP1B1, CYP1A2, CYP1A1, CYP2C19, CYP2D6, and CYP3A4 was 0.34 ± 0.08, 0.23 ± 0.04, 0.86 ± 0.01, 0.25 ± 0.02, 0.10 ± 0.003, and 1.28 ± 0.07 μM/min/pmol of CYP, respectively. Data are expressed as mean percentage of control enzyme activity for three independent experiments.