- 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
Negligible inhibition of UGT2B7 by diclofenac
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.
Recombinant expression system Baculovirus-insect cells
Cytochrome B5 Not available
Concentration of precipitant and % inhibition of UGT2B7 (values estimated from figure 5)
0.01 μM: -1 ± 3%
0.1 μM: 3 ± 5%
1 μM: 8 ± 4%
10 μM: 38 ± 2% (p < 0.05)
100 μM: 84± 1% (p < 0.05)
1000 μM: See above data
|Sample||Compound measured||Value||Measurement||Study sequence||Additional information||N replicates|
The amount of protein, the incubation time and the concentration of 4-MU used in the measurement of 4-MU glucuronidation were described in the method by Uchaipichat et al.
Microsomes expressing recombinant human UGT1A1 and UGT2B7 were obtained from BD Biosciences (Woburn, MA, United States);incubations (total volume 250 μL) contained phosphate buffer (100 mM) (pH 7.4), MgCl 2 (5 mM), cell lysate (83.3 μg/mL for UGT1A1 or 62.5 μg/mL for UGT2B7), UDPGA (5 mM), and 4-MU (substrate) (100 μM for UGT1A1 assay or 350 μM for UGT2B7 assay).