Table 2

Glucuronidation of flavonoids and anthraquinones by stably expressed human UGT1A8 and 1A10

SubstratesGlucuronide Formation
UGT1A8UGT1A10
pmol/min/mg protein
Flavonoids
 7-Hydroxyflavone53130
 Chrysin72476
 Apigenin845164
 Fisetin59865
 Quercetin54897
 Naringenin186055
 Genistein125988
Anthraquinones
 Anthraflavic acid80679
 Alizarin1500205
 Quinalizarin94796
 Emodin944233

Assays were performed using pH 7.4 Tris buffer at 37°C for 1.0 h and membrane preparations of HK293 cells expressing UGT1A8 or UGT1A10. The concentration of UDP-glucuronic acid was 2.0 mM and the aglycone concentrations were 0.5 mM. Values represent the average enzymatic rates from two different experiments.

  • ND, not detected (limit of detection is 2.0 pmol/min/mg protein).