The present study was designed to investigate the chemopreventive activity of grape seed proanthocyanidin extract in breast cancer cells. Dietary prevention is a cost-efficient strategy to reduce the risk of breast cancer. Grape seed proanthocyanidins are candidates for the prevention of human breast cancer associated with long-term exposure to environmental carcinogens. In the study, the activity of grape seed proanthocyanidin extract in suppressing cellular carcinogenesis induced by repeated exposures to low doses of environmental carcinogens was examined. A combination of the carcinogens 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and benzo[a]pyrene (B[a]P) were used at picomolar concentrations to repeatedly treat noncancerous human breast epithelial MCF10A cells. This treatment would be expected to induce reduced dependence on growth factors, anchorage-independent growth, and acinar-conformational disruption, all cancer-related cellular changes. Therefore, these properties were used as biological target endpoints in assessing the ability of grape seed proanthocyanidin extract to suppress combined NNK- and B[a]P-induced precancerous cellular carcinogenesis. The minimum (noncytotoxic) concentration of grape seed proanthocyanidin extract required for suppressing precancerous cellular carcinogenesis was identified. The authors found that hydroxysteroid-11-beta-dehydrogenase 2 (HSD11B2) may have a role in NNK- and B[a]P-induced precancerous carcinogenesis, and that its expression may act as a molecular target endpoint in grape seed proanthocyanidin extract's suppression of such carcinogenesis. In addition, the authors determined that the ability of grape seed proanthocyanidin extract to reduce gene expression of cytochrome-P450 enzymes CYP1A1 and CYP1B1 (which can bioactivate NNK and B[a]P) might contribute to the chemopreventive actions of the extract. The authors conclude that grape seed proanthocyanidin extract may be effective in preventing human breast cell carcinogenesis induced by repeated exposures to low doses of multiple environmental carcinogens.

The present study was designed to determine the antioxidant capacity, vitamin C content, and polyphenolic compounds of black currant, blueberry, raspberry, red currant, and cranberry extracts. The antioxidant capacity was determined using the FRAP (ferric reducing ability of plasma) assay, a simple test of total antioxidant power. The vitamin C and phenolic and polyphenolic compounds contents of the berries was determined by reversed-phase HPLC-PDA-MS3 and reversed-phase HPLC-PDA with an online antioxidant detection system. A variety of anthocyanins were found to be the major contributor to the antioxidant capacity of black currants and blueberries. Lower antioxidant capacity was found for red currants and cranberries; this appeared to be due mainly to the lower anthocyanin content of these berries. Raspberries also were found to have a lower anthocyanin content than black currants and blueberries. However, this did not translate into significantly lower antioxidant capacity because raspberries contain the ellagitannins sanguin H-6 and lambertianin C. These ellagitannins were responsible for 58% of the antioxidant capacity of the raspberries. Vitamin C was responsible for 18% to 23% of the antioxidant capacity of black currants, red currants, and cranberries, as well as 11% of the antioxidant capacity of raspberries. However, the vitamin C content of the blueberry extract was not significant and did not contribute to its antioxidant capacity. The cranberry extract contained procyanidin dimers, which contributed 7% of its antioxidant capacity. However, the authors were unable to measure the contribution of polymeric proanthocyanidins to the antioxidant capacity of the five berries since they were not amenable to analysis by reversed-phase HPLC.

In vitro and other tumor studies have demonstrated that cranberry extracts and component molecules retard the growth and proliferation of breast cancer cells, as well as some other cancers. The observed antiproliferative properties are likely to be the result of the proanthocyanidin oligomers, flavonol and anthocyanin glycosides, and triterpenoids contained in cranberries. These substances might act in concert to inhibit carcinogenesis.

The present study was designed to investigate the cytotoxic effects of polyphenolic extracts of the principal flavonoid classes of cranberries. Cranberry flavonoids were screened against solid tumor cells lines, identifying two fractions, comprised mainly of proanthocyanidins, with potential anticancer activity. Analysis using spectrometry indicated the presence of A-type proanthocyanidins with 1-4 linkages containing between 2-8 epicatechin units, with a maximum of one epigallocatechin unit. Proanthocyanidins were found to exhibit in vitro cytotoxicity against platinum-resistant human ovarian, neuroblastoma and prostate cancer cell lines (IC50 = 79-479 µg/mL), but were not cytotoxic to lung fibroblast cells. Proanthocyanidins treatment of SKOV-3 ovarian cancer cells resulted in apoptotic changes. In addition, proanthocyanidins were found to act synergistically with paraplatin in the ovarian cancer cells. Pretreatment of SKOV-3 cells with proanthocyanidins (106 µg/ml) produced in a significant decrease in the paraplatin IC50 value. Co-treatment of SKOV-3 cells with proanthocyanidins plus paraplatin resulted in less cell proliferation at lower concentrations than treatment with either individually. The authors conclude that cranberry proanthocyanidins exhibit cell-line specific cytotoxicity, induce apoptotic markers and augment cytotoxicity of paraplatin in platinum-resistant ovarian cancer cells.

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.

In the present study, extracts of six berries (blackberry, black raspberry, blueberry, cranberry, red raspberry and strawberry) were evaluated for their phenolic constituents and ability to inhibit growth of various human cancer cell lines. Berries contain a remarkable range of phytochemicals with biological properties such as anti-inflammatory, antioxidant, anticancer, and anti-neurodegenerative activities. The main classes of berry phenolics were found to be anthocyanins, proanthocyanidins, flavonols, ellagitannins, gallotannins, and phenolic acids. The berry extracts were evaluated for their ability to inhibit the growth of human oral (KB, CAL-27), breast (MCF-7), prostate (LNCaP), and colon (HT-29, HCT116) cancer cell lines at concentrations varying from 25 to 200 μg/mL. The growth of all the tumor cells was found to be inhibited increasingly with increasing concentrations of berry extract, with different degrees of potency for different berries and cell lines. The extracts were also evaluated for their ability to increase apoptosis of the COX-2 expressing colon cancer cell line, HT-29. Black raspberry and strawberry extracts were found to have the most significant pro-apoptotic effects against these cells.

This study evaluated the activity of flavonoid-rich fractions of cranberry presscake and whole cranberry against human tumor cell lines of glioblastoma multiforme, colon cancer, and androgen-independent prostate cancer. Both fractions significantly retarded the growth of the tumors.

The current study was designed to identify the components of cranberry that may account for its anticancer properties and to determine how they inhibit proliferation. Cranberry presscake was fractionated. An acidified methanol eluate containing flavonoids (designated Fraction 6) was found to have strong antiproliferative activity against all the cancer cell lines tested. An androgen-dependent prostate cell line was the most affected of those tested, while an estrogen-independent breast line and an androgen-independent prostate line were the least vulnerable. Other human tumor lines originating from breast, skin, colon, lung, and brain had intermediate sensitivity to Fraction 6. It was shown that Fraction 6 blocked cell cycle progression and induced cells to undergo apoptosis in a dose-dependent manner in one breast cancer cell line.