Transporter Herbal compound Substrate/ Inhibitor IC50 (μM) Ki (μM) Km (μM) Reference OCT1 Quercetin Substrate ND ND 2.2 ± 0.2 [83] OCT3 Wogonin Inhibitor 3.7 ± 1.3 ND ND [33] ND: not determined

Table 4: The interactions of herbal compounds with human OCTs.