Compound 1 (10 μM) was incubated in 0.1M Tris-HCl buffer, pH 7.4, 10 mM MgCl₂, and 4 mM UDPGA for 20 min at 37°C with 0.2 mg/ml of Sf9 insect cell microsomes (UGT1A1, UGT1A6, UGT1A7, and UGT1A10) or AHH-1 human B lymphoblastoid cell microsomes (UGT1A4 and UGT1A9) treated with 0.5 mg of CHAPS/mg of protein for 20 min at 4°C. Detection limit was 12.5 pmol/min/mg of protein. Each value represents the mean ± S.D. (n = 3).

• N.D., not detected.