(A) Impact of H. verticillata aqueous extract on CYP activities. Human CYPs 1A1, 1A2 catalyzed 7-ethoxy-3-cyanocoumarin (CEC) (0.5, 5.0 μM respectively) metabolism, CYP1B1 catalyzed 7-ethoxyresorufin (ERes) (0.37 μM) metabolism and CYP3A4 catalyzed 7-benzyloxy-4-trifluoromethylcoumarin (BFC) (50 μM) metabolism were determined in the presence of varying concentrations of reconstituted freeze-dried aqueous extract of H. verticillata ranging from 0.02 to 575 µg/mL, as described in the Materials and Methods section. Control enzyme activity (mean ± SEM) for CYPs 1A1, 1A2, 1B1 and 3A4 was 1.43 ± 0.2, 1.49 ± 0.001, 0.95 ± 0.001 and 0.86 ± 0.000 (µM/min/pmol) of CYP, respectively. Data are expressed as mean percentage of enzyme activity for experiments carried out in triplicate; (B) Summary of results.