PGP and cancer: Many plant-derived compounds are known to enhance the chemotherapeutic effects of anticancer agents by modulating the main ABC (ATP-binding cassette) transporters responsible for cancer drug resistance, including P-gp, MRPs and BCRP, as well as regulating both cell survival- and cell death-related signaling pathways, which makes them a promising group of low toxicity candidates for reversing MDR [37].