Fig. 3.
Effect of chemical inhibitors of UGT1A6 (phenylbutazone) and UGT1A9 (carvacrol) on the glucuronidation of ET (A, B, C, and D) and 4-ME (E, F, G, and H) in HLM, UGT1A6, and UGT1A9. Glucuronidation of ET and 4-ME by HLM and UGT isoforms were measured at three concentrations (10, 100, and 300 μM) and incubated in the presence of phenylbutazone or carvacrol at low three concentrations (50, 100, and 200 μM). All protein concentrations were 0.5 mg/ml, incubation time for ET and 4-ME in microsomes and UGTs ranged from 15 to 60 minutes. Control experiments were incubated without chemical inhibitors. Samples were processed and analyzed by UHPLC-MS2. All incubations were performed in triplicate. Each column represents mean percentage control of formation rates of these three metabolites, and error bars are standard deviations of the mean. An asterisk (*) indicates a statistically significant difference (P < 0.05) compared with the control according to Student’s t test.