• Icariin;
  • Solute Carrier Transporters;
  • OATP1B3;
  • OATP2B1


Solute carrier transporters (SLCs), in particular the organic anion transporting polypeptides (OATPs) and organic anion/cation transporters (OATs/OCTs), are responsible for the cellular entry of many clinically important drugs in body. They largely influence drug safety and efficacy. Icariin is a flavonol widely present in many herbal preparations, which is used to improve sexual function and prevent osteogenesis. However, precautions are necessary in therapies containing icariin due to its involvement in drug–drug/herb interactions, possibly mediated through competing drug uptake via membrane-transporter proteins. This study is the first to comprehensively evaluate the interactions between icariin and a range of essential SLCs. Our data demonstrated that icariin can significantly inhibit OATP1B3- and OATP2B1-mediated cellular uptake of specific substrates (IC50 of 3.0 ± 1.3 and 6.4 ± 1.9 μM, respectively). Our study revealed that icariin can potentially compete with coadministrated drugs for particular SLCs, which may impact the therapeutic outcome of regimens.