PGP and ovarian carcinoma: It has been reported that P-gP is over-expressed in paclitaxel (PTX)-resistant ovarian cancer cells, and grape seed, procyanidi, is a natural polyphenol supplement that can inhibit the expression of P-gP through downregulating the nuclear factor kappa-light chain-enhancer of activated B cells (NF-κB) activity and the mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinases (ERK) pathway [50].