- Natural product: Kratom (Mitragyna speciosa)
- Associated study: Effects of mitragynine and 7-hydroxymitragynine (the alkaloids of Mitragyna speciosa Korth) on 4-methylumbelliferone glucuronidation in rat and human liver microsomes and recombinant human uridine 5’- diphospho-glucuronosyltransferase isoforms
In Vitro Enzyme Inhibition Experiment
No inhibition of UGT in human liver microsome activity by 7-hydroxymitragynine
Negligible Inhibition was detected. Cutoff used —
IC50 > 10 μM are low potential inhibitors.
1 μM < IC50 < 10 μM are moderate potential inhibitors.
IC50 < 1 μM are high potential inhibitors.
- UGT
Cell fraction Pooled human liver microsomes -7999662
Results
The IC50 values were all greater than the highest concentrations used (IC50 > 100 μM) since inhibition at more than 50% did not occur at the highest concentration.
Concentration of precipitant and % inhibition of pooled human liver microsomes (intermediate values estimated from figure 3)
0.01 μM: 5 ± 1%
0.1 μM: 9 ± 5%
1 μM: 10 ± 2% (P < 0.05)
10 μM:10 ± 3% (P < 0.05)
100 μM: See above data
| Sample | Compound measured | Value | Measurement | Study sequence | Additional information | N replicates |
|---|
Experimental Conditions
Pooled human liver microsomes were purchased from Sigma-Aldrich; The enzyme activity assay mixture (250 μL) contained Tris-HCl (100 mM) (pH 7.4), MgCl (5 mM), microsomal protein (0.1 mg/mL), Triton X-100 (0.005%), UDPGA (3 mM), and 4-MU (100 μM).
Tested concentrations of precipitant only up to 100 μM due to limited solubility
Control=no inhibitor
0.1 mg/mL
Commercially available
250 μL
30 min
MgCl2
UDPGA
Not available
Not available
100 μM
0.01-100 μM