UCLA Center for Human Nutrition

Pomegranate (Punica granatum L.) fruits are widely consumed as juice (PJ). The potent antioxidant and anti-atherosclerotic activities of PJ are attributed to its polyphenols including punicalagin, the major fruit ellagitannin, and ellagic acid (EA). Punicalagin, EA, a standardized total pomegranate tannin extract (TPT) and PJ were evaluated for in vitro antioxidant, antiproliferative and apoptotic activities. The antioxidative bioassays used included inhibition of lipid peroxidation and Trolox Equivalent Antioxidant Capacity (TEAC) assays. The antiproliferative assays targeted human oral (KB, CAL27), colon (HT-29, HCT116, SW480, SW620) and prostate (RWPE-1, 22Rv1) tumor cells. Apoptotic effects were evaluated against the HT-29 and HCT116 colon cancer cell lines. Punicalagin, EA and TPT were evaluated at 12.5-100 g/mL for antiproliferative assays. However, to evaluate the synergistic and/or additive contributions from other PJ phytochemicals, PJ was tested at concentrations normalized to deliver equivalent amounts of punicalagin (w/w). Punicalagin, EA, TPT and PJ were all evaluated at 10 g/mL concentrations for antioxidant properties and at 100 g/mL concentrations for apoptotic effects. PJ showed greatest antiproliferative activity against all cell lines by inhibiting proliferation from 30-100%. At 100 g/mL, PJ, EA, punicalagin and TPT induced apoptosis in HT-29 colon cells. However, in the HCT116 colon cells, EA, punicalagin and TPT but not PJ induced apoptosis. The trend in antioxidant activity was PJ>TPT>punicalagin>EA. The superior bioactivity of PJ compared to its purified polyphenols illustrated the multifactorial effects and chemical synergy of the action of multiple compounds compared to single purified active ingredients.