Impact of ABC transporters, glutathione conjugates in MDR and their modulation by flavonoids: an overview

Overexpression of ATP-binding cassette (ABC) transporter and glutathione conjugates results in efflux of cytotoxic agent from tumor cells leading to multidrug resistance (MDR). Many MDR inhibitors have been identified but none of them have been proven clinically valuable without side effects. Efforts are continue to develop an ideal MDR inhibitor. Recently, herbal modulation of ABC transporter and glutathione conjugates by flavonoids is emerging as popular therapy in MDR. In this review, we have covered structure, function of different ABC transporters and glutathione-mediated MRP overexpression. This review also focuses on the problems with existing MDR inhibitors, modulation of ABC transporter and glutathione-S-transferase by flavonoids.