The present study was designed to investigate the anti-breast cancer activities of pomegranate ellagitannin compounds. Estrogen stimulates the growth of estrogen-responsive tumors. Androgen is converted to estrogen in the body by the aromatase enzyme, a process which plays a key role in breast carcinogenesis. Pomegranate fruit, which is a rich source of ellagitannins, has attracted notice because of its reported anticancer and anti-atherosclerotic properties. Pomegranate ellagitannins hydrolyze upon consumption, releasing ellagic acid, which is then converted to 3,8-dihydroxy-6H-dibenzo[b,d]pyran-6-one (urolithin) derivatives by microflora in the gut. In the study, a panel of 10 ellagitannin-derived compounds, including ellagic acid, gallagic acid, urolithin A, and urolithin B, as well as the urolithins' acetylated, methylated, and sulfated analogues (prepared in the authors' laboratory), were tested for their ability to inhibit aromatase activity and testosterone-induced breast cancer cell proliferation. The compounds were screened using a microsomal aromatase assay. Six of them were found to have anti-aromatase activity, of which urolithin B was found to most strongly inhibit aromatase activity in a live cell assay. Further testing using kinetic analysis demonstrated mixed inhibition, indicating more than one inhibitory mechanism for urolithin B. Proliferation assays also demonstrated that urolithin B significantly inhibited testosterone-induced MCF-7aro cell proliferation. MCF-7aro breast cancer cells are estrogen receptor positive/aromatase positive and demonstrate increased cell proliferation in the presence of testosterone. The remaining ellagitannin-derived test compounds also were found to exhibit antiproliferative activity, but to a lesser degree than urolithin B. The authors conclude that pomegranate ellagitannin–derived compounds have potential for the prevention of estrogen-responsive breast cancers.

The present study was designed to investigate the affect of punicic acid, a component of pomegranate seed oil, on human breast cancer cells. Pomegranates (Punica granatum) contain a large number of potentially bioactive substances, and various extracts have been used as anticancer agents. Punicic acid is an omega-5 long chain polyunsaturated fatty acid found in pomegranate seed oil. Other long chain fatty acids have been reported to have chemopreventive properties. The study measured the effects of punicic acid on the growth of both MDA-MB-231 estrogen insensitive breast cancer cells and MDA-ERalpha7 breast cancer cells (an estrogen sensitive cell line developed from MDA-MB-231 cells). Proliferation was found to be 92% inhibited for MDA-MB-231 cells and 96% inhibited for MDA-ERalpha7 cells compared to untreated cells by 40 microM punicic acid. In addition, punicic acid induced apoptosis in MDA-MB-231 cells by 86% and in MDA-ERalpha7 cells by 91%, compared to untreated control cells, and was shown to disrupt cellular mitochondrial membrane potential. Further experimentation demonstrated that adding 20 microM of the antioxidant tocotrienol to the assays resulted in reversal of the effects of punicic acid on proliferation, apoptosis and disruption of the mitochondrial membrane potential. The role of PKC signaling in the anticancer effects of punicic acid was also evaluated by performing proliferation assays in the presence of the PKC inhibitor bisindolymaleimide I. Adding the PKC inhibitor reduced the inhibition of proliferation induced by punicic acid in both the MDA-MB-231 and MDA-ERalpha7 cells. The authors conclude that punicic acid has breast cancer inhibitor properties that are dependent on lipid peroxidation and the PKC pathway.

Feline mammary cancer (FMC) is similar to human estrogen receptor negative (ER-) breast cancer in its invasive behavior, histologic appearance, and relatively poor prognosis. In the present study, supplementation with pomegranate was evaluated in an ER- human breast cancer cell line (MDA-MB-231) as a model for FMC. ER- cells were exposed to pomegranate juice at various concentrations (0.5%, 1%, 5%) and to Cisplatin (a chemotherapy drug) at 5 ug/ml, 10 ug/ml, and 15 ug/ml doses for 48 and 72 hours. Proliferation of the ER- breast cancer cells was found to be inhibited by pomegranate juice in a dose- and time-dependent manner and the response was comparable to that of high-dose Cisplatin.

Using six different measures, the study evaluated the antioxidant potency of the following juices and drinks: apple juice, açaí juice, black cherry juice, blueberry juice, cranberry juice, Concord grape juice, orange juice, red wines, iced tea beverages, and pomegranate juice. All of the juices were commercial brands available in the U.S. market. Pomegranate juice was found to have antioxidant potency that was more than 20 percent greater than any of the other beverages tested. The antioxidant capacity of the beverages were ranked in the following order: pomegranate juice > red wine > Concord grape juice > blueberry juice > black cherry juice, açaí juice, cranberry juice > orange juice, iced tea, apple juice.

To test the antiproliferative and proapoptic effects of pomegranate juice, the authors used aggressive estrogen receptor negative (ER-) breast cancer cell lines MDA 231 and SUM 149, an inflammatory breast cancer line. MCF10A immortalized breast epithelial cells were used as normal controls. All of the cells were treated with an extract of fermented pomegranate juice at various doses from 50 to 400 mcg/ml for 48 hours and proliferation was assessed. The pomegranate juice extract was associated with a significant dose-dependent decrease in the rate of proliferation and induction of apoptosis, which appeared to be selective for the cancer cells. To evaluate the efficacy of pomegranate for cancer prevention, the authors used a proprietary pomegranate fruit extract emulsion (consisting of seed oil and concentrated fermented aqueous extracts) in three groups of Her2/neu transgenic mice. The mice were gavaged with (1) pomegranate fruit extract emulsion; (2) a comparable inert vegetable oil-in-water emulsion placebo; or (3) no treatment. At approximately 100 days into the experiment, 100% of the pomegranate fruit extract treated group had no tumors, 28% of the placebo group had tumors, and 30% of the no treatment control group had tumors.

This article was prompted by the profusion of pomegranate products "standardized to 40% ellagic acid" that recently appeared in the marketplace. The authors review the existing studies of pomegranates as well as the virtues and dangers of ellagic acid, and conclude that synergy among the various pomegranate components and phytochemicals is the most important factor for assessing pomegranate nutraceutical preparations, and not simply the concentration of ellagic acid. They suggest that nutraceutical products should be designed and engineered to maximize therapeutic or chemopreventive synergy, rather than simply maximizing the concentration of a single phytochemical. They further conclude that ellagic acid concentration in well-designed final products is likely to have a lower optimal therapeutic concentration than 40%.

The anticancer effects of pomegranate extracts and genistein were investigated using MCF-7 human breast cancer cells. The cells were cultured for 48 hours and then exposed to the pomegranate extracts and genistein for 24 hours in single and combination treatments. Both pomegranate extracts and genistein had significant dose- and time-dependent cytotoxic and growth inhibition effects on the breast cancer cells. Cytotoxicity and growth inhibition were found to be significantly higher in the combination treatments than in treatments with either agent alone.

The present study was designed to evaluate the potential chemopreventive efficacy of (1) pomegranate fermented juice polyphenols; (2) a purified chromatographic peak of pomegranate fermented juice polyphenols (Peak B); and (3) whole pomegranate seed oil. The carcinogen 7,12-dimethylbenz[a]anthracene (DMBA) was used to promote mammary tumors in a mouse mammary organ culture. The glands were subsequently harvested and tumors counted visually. While pomegranate fermented juice polyphenols resulted in a 42% reduction in the number of lesions compared with a control group, Peak B and pomegranate seed oil each resulted in 87% fewer tumors.

Pomegranate contains estrogens (estradiol, estrone, and estriol) and shows estrogenic activities in mice. The present study investigated whether pomegranate extract can remediate experimental menopausal symptoms in mice which have had their ovaries removed. Depression (prolongation of the immobility time in forced swimming test) and bone mineral density of the tibia were measured after ovariectomy. The structure and metabolism of bone were also analyzed. Administration of pomegranate extract (juice and seed extract) for 2 weeks to the mice was found to prevent loss of uterus weight, shorten the immobility time, and normalize the ovariectomy-induced decrease of bone mineral density. The pomegranate extract was found to inhibit ovariectomy-stimulated bone turnover. The authors concluded that pomegranate might be clinically effective on a depressive state and bone loss in menopausal syndrome in women.

The present study used several methods to evaluate the anti-angiogenic potential of pomegranate seed oil and fermented juice polyphenols using both estrogen sensitive (MCF-7) and estrogen resistant (MDA-MB-231) human breast cancer cells. Based on the results of various methods, the authors concluded that they had demonstrated anti-angiogenic potential of pomegranate fractions.

In the present study, fermented pomegranate juice, aqueous pomegranate pericarp extract, and cold-pressed pomegranate seed oil were shown to block endogenous active estrogen biosynthesis which inhibited aromatase activity by 60–80%. In a yeast estrogen screen, lyophilized fresh pomegranate juice effected a 55% reduction of the estrogenic activity of 17--estradiol, whereas the lyophilized juice by itself displayed only minimal estrogenic action. Fermented pomegranate juice polyphenols consistently showed approximately twice the anti-proliferative effect as fresh pomegranate juice polyphenols against estrogen-dependent (MCF-7) and estrogen-independent (MB-MDA-231) cells. Pomegranate seed oil effected 90% inhibition of proliferation of MCF-7, 75% inhibition of invasion of MCF-7 across a Matrigel membrane, and 54% apoptosis in MDA-MB-435 estrogen receptor negative metastatic human breast cancer cells. In addition, fermented juice polyphenols effected 47% inhibition of cancerous lesion formation induced by the carcinogen 7,12-dimethylbenz[a]anthracene (DMBA in a murine mammary gland organ culture.

The current study examined estrogen-like activity in pomegranate juice. Both pomegranate juice and its methanol eluate competed with 17β-estradiol for estrogen receptor binding and also stimulated the proliferation of human ER-positive breast cancer cells (MCF-7) in vitro. Furthermore, they effectively increased uterine weight in ovariectomized rats.