Isolation and characterization of a novel oligomeric proanthocyanidin with significant anti-cancer activities from grape stems (Vitis vinifera).

Novel proanthocyanidin fractions from grape stem extracts were purified using Amberlite XAD-1180N, Sephadex-LH-20, Toyopearl HW40F and reverse phase high-performance liquid chromatography. Two key compounds were estimated as epigallocatechin-(epicatechin) gallate using electron-spray ionization time-of-flight mass spectrometry. Epigallocatechin-(epicatechin) gallate (compound 1) showed significant anti-cancer activity in PC-3 prostate cancer cells.