Effect of substrate concentrations on excretion rates (a), intracellular amounts (b), CL (c), and f_met (d) of Dio-7-G, Dio-3′-G, Chr-7-G, and Chr-4′-G.

Three samples (500 μL) were obtained at 15, 30, and 60 min and replaced with fresh loading solution (500 μL) that contains diosmetin or chrysoeriol. The excretion rates of glucuronides were calculated from the slope of the amount-versus-time curves. The intracellular amounts of the glucuronides were determined at the end of the excretion experiments after the cells were washed twice with ice-cold HBSS. Each column corresponds to the average of three determinations with error bars representing the S.D. The “*” (for Dio-7-G or Chr-7-G) or “^#” (for Dio-3′-G or Chr-4′-G) symbol means a statistically significant difference between-group, at p < 0.05; “**” or “^##” means p < 0.01; “***” or “^###” means p < 0.001.