TABLE 6.
Inhibition kinetics for mitragynine against P450 activities
| Enzyme | Substrate | Reaction | Enzyme System | Monitoring Method | Mode of Inhibition | Inhibition Kinetics |
|---|---|---|---|---|---|---|
| CYP2C9 | luciferin H | luminometric | noncompetitive | Ki = 155 μM | ||
| CYP2D6 | dextromethorphan | O-demethylation | HLMs | LCMS | competitive | Ki = 1.17 μM |
| dextromethorphan | O-demethylation | HLMs | LCMS | Ki = 1.1 μM | ||
| luciferin ME-EGE | luminometric | noncompetitive | Ki = 12.86 μM | |||
| CYP3A4/5 | midazolam | 1’-hydroxylation | HLMs | LCMS | time dependent | KI = 4.1 μM; kinact = 0.068 min−1 |
| midazolam | 1’-hydroxylation | HIMs | LCMS | time dependent | KI = 4.2 μM; kinact = 0.079 min−1 | |
| luciferin-BE | luminometric | competitive | Ki = 380 μM |
luciferin-BE, luciferin 6’ benzyl ether; luciferin H, 6’deoxyluciferin; luciferin ME-EGE, ethylene glycol ester of luciferin 6’ methyl ether.