The antioxidant activity of pomegranate juices was evaluated by four different methods (ABTS, DPPH, DMPD, and FRAP) and compared to those of red wine and a green tea infusion. Commercial pomegranate juices showed an antioxidant activity (18-20 TEAC) three times higher than those of red wine and green tea (6-8 TEAC). The activity was higher in commercial juices extracted from whole pomegranates than in experimental juices obtained from the arils only (12-14 TEAC). HPLCDAD and HPLC-MS analyses of the juices revealed that commercial juices contained thepomegranate tannin punicalagin (1500-1900 mg/L) while only traces of this compound were detected in the experimental juice obtained from arils in the laboratory. This shows that pomegranate industrial processing extracts some of the hydrolyzable tannins present in the fruit rind. This could account for the higher antioxidant activity of commercial juices compared to the experimental ones. In addition, anthocyanins, ellagic acid derivatives, and hydrolyzable tannins were detected and quantified in the pomegranate juices.
Antioxidant activities of freeze-dried preparations of a 70% acetone extract of pomegranate (Punica granatum L.) and its three major anthocyanidins (delphinidin, cyanidin, and pelargonidin) were evaluated. Free radical scavenging activities were examined using an ESR technique with spin trapping; DMPO for hydroxyl (OH) and superoxide (O2-) radicals; and [(MGD)2Fe2+] for nitric oxide (NO). Inhibitory effects on lipid peroxidation were estimated by the levels of malonaldehyde and 4-hydroxyalkenals in rat brain homogenates. Pomegranate extract exhibited scavenging activity against OH and O2-. Anthocyanidins inhibited a Fenton reagent âOH generating system possibly by chelating with ferrous ion. Anthocyanidins scavenged O2- in a dose-dependent manner. The ID50 values of delphinidin, cyanidin, and pelargonidin were 2.4, 22, and 456 μM, respectively. In contrast, anthocyanidins did not effectively scavenge NO. Anthocyanidins inhibited H2O2-induced lipid peroxidation in the rat brain homogenates. The ID50 values of delphinidin, cyanidin, and pelargonidin for them were 0.7, 3.5, and 85 μM, respectively. These findings suggest that the above anthocyanidins contribute to the antioxidant activity of pomegranate fruits.
The antioxidant and eicosanoid enzyme inhibition properties of pomegranate (Punica granatum) fermented juice and seed oil flavonoids were studied. The pomegranate fermented juice (pfj) and cold pressed seed oil (pcpso) showed strong antioxidant activity close to that of butylated hydroxyanisole (BHA) and green tea (Thea sinensis), and significantly greater than that of red wine (Vitis 6itifera). Flavonoids extracted from pcpso showed 31–44% inhibition of sheep cyclooxygenase and 69–81% inhibition of soybean lipoxygenase. Flavonoids extracted from The pomegranate fermented juice showed 21–30% inhibition of soybean lipoxygenase though no significant inhibition of sheep cyclooxygenase. The pcpso was analyzed for its polyphenol content and fatty acid composition. Total polyphenols in pcpso showed a concentration by weight of approximately 0.015%. Pcpso fatty acid composition showed punicic acid (65.3%) along with palmitic acid (4.8%), stearic acid (2.3%), oleic acid (6.3%), linoleic acid (6.6%) and three unidentified peaks from which two (14.2%) are probably isomers of punicic acid (El-Shaarawy, M.I., Nahpetian, A., 1983).
Pomegranate (Punica granatum L.) fruits are widely consumed as juice (PJ). The potent antioxidant and anti-atherosclerotic activities of pomegranate juice are attributed to its polyphenols including punicalagin, the major fruit ellagitannin, and ellagic acid (EA). Punicalagin is the major antioxidant polyphenol ingredient in pomegranate juice. Punicalagin, EA, a standardized total pomegranate tannin (TPT) extract and pomegranate juice were evaluated for in vitro antiproliferative, apoptotic and antioxidant activities. Punicalagin, EA and TPT were evaluated for antiproliferative activity at 12.5–100 Ag/ml on human oral (KB, CAL27), colon (HT-29, HCT116, SW480, SW620) and prostate (RWPE-1, 22Rv1) tumor cells. Punicalagin, EA and TPT were evaluated at 100 Ag/ml concentrations for apoptotic effects and at 10 Ag/ml concentrations for antioxidant properties. However, to evaluate the synergistic and/or additive contributions from other pomegranate juice phytochemicals, pomegranate juice was tested at concentrations normalized to deliver equivalent amounts of punicalagin (w/w). Apoptotic effects were evaluated against the HT-29 and HCT116 colon cancer cell lines. Antioxidant effects were evaluated using inhibition of lipid peroxidation and Trolox equivalent antioxidant capacity (TEAC) assays. Pomegranate juice showed greatest antiproliferative activity against all cell lines by inhibiting proliferation from 30% to 100%. At 100 Ag/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 pomegranate juice induced apoptosis. The trend in antioxidant activity was PJ>TPT>punicalagin>EA. The superior bioactivity of pomegranate juice compared to its purified polyphenols illustrated the multifactorial effects and chemical synergy of the action of multiple compounds compared to single purified active ingredients.
