22 research outputs found

    Parameters of the enzymatic reactions used to determine the activities of P450 enzymes.

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    <p><b>Note:</b><b><i>a</i></b>. The linear range was determined by visual inspection; parameters for substrate concentration, wavelength and CYP450 concentration were provided by the kit manufacturer.</p

    IC<sub>50</sub> values of the ginsenosides and sapogenins against P450 enzymes.

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    <p><b>Note:</b><b><i>a</i></b>. The percent inhibition of ginsenosides against the respective P450 enzymes is shown when its IC<sub>50</sub> value is greater than the maximum concentration assayed.</p><p><b><i>b</i></b>. The maximum concentration of ginsenosides evaluated for their effects on CYP2C9 and CYP2D6 were 50 µM due to the marked solvent effect of 1% methanol on these two P450 enzymes (inhibition by 42.4% and 27.5%, respectively). When the final concentration of methanol was decreased to 0.5%, the solvent effects were acceptable for these two enzymes (10.1% and 18.9%, respectively). 1% methanol had no inhibition against CYP1A2 and CYP3A4 and had an acceptable inhibitory effect on CYP2C19 (9.7%).</p><p><b><i>c</i></b>. Positive control compounds were α-naphthoflavone (for CYP1A2), sulfaphenazole (CYP2C9), miconazole nitrate salt (CYP2C19), quinidine (CYP2D6), and ketoconazole (CYP3A4), respectively.</p><p><b><i>d</i></b>. A.A. = apparent activation. 100 µM 25-OH-PPD and 25-OH-PPT increased the turnover of Vivid® CYP3A4 red by more than 100%.</p
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