PGP and cancer: Among polyphenols that exhibit MDR-reversing properties, curcumin has been reported to reverse MDR in P-gp overexpressing cancer cells in many cancers, including the human cervical carcinoma cell line (KB–V1) [12], the doxorubicin-resistant lung cancer cells (A549/DOX) [13], and the Adriamycin-resistant leukemic cell lines (K562/Adr) [14].