Potential food-drug interaction risk of thymoquinone with warfarin.

Thymoquinone, predominant bioactive compound in Nigella sativa L. (N.sativa) oil, may inhibit the activity of cytochrome P450 2C9 (CYP2C9). However, it is not clear whether thymoquinone can affect the pharmacokinetic behavior of warfarin. Thus, we further to investigate the effect of thymoquinone on warfarin 7-hydroxylation activity and to quantitatively evaluate their food-drug interactions (FDIs) potential. Our data demonstrated that thymoquinone could inhibit warfarin 7-hydroxylase activity with IC value of 11.35 ± 0.25 μM. The kinetic analysis indicated that thymoquinone exhibited competitive inhibition on warfarin 7-hydroxylation with K value of 3.50 ± 0.44 μM. FDIs risk prediction suggested that coadministration of thymoquinone (>18 mg/day) or dietary supplements containing thymoquinone (N.sativa > 1 g/day or N. sativa oil >1 g/day) might influence pharmacokinetic behavior of warfarin. In conclusion, coadministration of thymoquinone or dietary supplements containing thymoquinone in warfarin-treated patients would likely trigger off unexpected potential drug interactions.