Dr. Ron’s Research Review – February 9, 2011

This week’s research review contains information on berries.

A recent study examined the effects of berries on modulating enzymes of estrogen metabolism. Estradiol treatment caused a 48-fold increase in cytochrome P450), which was attenuated by both black raspberry and blueberry diets to 12- and 21-fold, respectively. There was a 5-fold increase in 17beta-hydroxysteroid dehydrogenase 7, and this was moderately abrogated to approximately 2-fold by all supplementation. (Aiyer and Gupta 2010)

Berry phenolics have antimicrobial properties and mechanisms of action against severe human pathogens (Nohynek, Alakomi et al. 2006)

Bioactive berry compounds are novel tools against human and human intestinal pathogens (Puupponen-Pimia, Nohynek et al. 2005) (Puupponen-Pimia, Nohynek et al. 2005)

Blackberry, black raspberry, blueberry, cranberry, red raspberry, and strawberry extracts inhibit growth and stimulate apoptosis of human cancer cells in vitro (Seeram, Adams et al. 2006)

Dr. Ron


Articles

                            

Berries and ellagic acid prevent estrogen-induced mammary tumorigenesis by modulating enzymes of estrogen metabolism

            (Aiyer and Gupta 2010) Download

To determine whether dietary berries and ellagic acid prevent 17beta-estradiol (E(2))-induced mammary tumors by altering estrogen metabolism, we randomized August-Copenhagen Irish rats (n = 6 per group) into five groups: sham implant + control diet, E(2) implant + control diet (E(2)-CD), E(2) + 2.5% black raspberry (E(2)-BRB), E(2) + 2.5% blueberry (E(2)-BB), and E(2) + 400 ppm ellagic acid (E(2)-EA). Animals were euthanized at early (6 wk), intermediate (18 wk), and late (24 wk) phases of E(2) carcinogenesis, and the mammary tissue was analyzed for gene expression changes using quantitative real-time PCR. At 6 weeks, E(2) treatment caused a 48-fold increase in cytochrome P450 1A1 (CYP1A1; P < 0.0001), which was attenuated by both BRB and BB diets to 12- and 21-fold, respectively (P < 0.001). E(2) did not alter CYP1B1 levels, but both berry and EA diets significantly suppressed it by 11- and 3.5-fold, respectively, from baseline (P < 0.05). There was a 5-fold increase in 17beta-hydroxysteroid dehydrogenase 7 (17betaHSD7), and this was moderately abrogated to approximately 2-fold by all supplementation (P < 0.05). At 18 weeks, CYP1A1 was elevated by 15-fold in E(2)-CD and only E(2)-BB reduced this increase to 7-fold (P < 0.05). Catechol-O-methyltransferase expression was elevated 2-fold by E(2) treatment (P < 0.05), and all supplementation reversed this. At 24 weeks, CYP1A1 expression was less pronounced but still high (8-fold) in E(2)-treated rats. This increase was reduced to 3.2- and 4.6-fold by E(2)-BRB and E(2)-EA, respectively (P < 0.05), but not by E(2)-BB. Supplementation did not alter the effect of E(2) on steroid receptors. The diets also significantly suppressed mammary tumor incidence (10-30%), volume (41-67%), and multiplicity (38-51%; P < 0.05). Berries may prevent mammary tumors by suppressing the levels of E(2)-metabolizing enzymes during the early phase of E(2) carcinogenesis.

Dietary berries and ellagic acid diminish estrogen-mediated mammary tumorigenesis in ACI rats

            (Aiyer, Srinivasan et al. 2008) Download

Estrogen acts as a complete mammary carcinogen in ACI rats. Prevention studies in this model allowed us to identify agents that are effective against estrogen-induced mammary carcinogenesis. In this study, we investigated efficacy of dietary berries and ellagic acid to reduce estrogen-mediated mammary tumorigenesis. Female ACI rats (8-9 wk) were fed either AIN-93M diet (n = 25) or diet supplemented with either powdered blueberry (n = 19) and black raspberry (n = 19) at 2.5% wt/wt each or ellagic acid (n = 22) at 400 ppm. Animals received implants of 17beta-estradiol 2 wk later, were palpated periodically for mammary tumors, and were euthanized after 24 wk. No differences were found in tumor incidence at 24 wk; however, tumor volume and multiplicity were reduced significantly after intervention. Compared with the control group (average tumor volume = 685 +/- 240 mm3 and tumor multiplicity = 8.0 +/- 1.3), ellagic acid reduced the tumor volume by 75% (P < 0.005) and tumor multiplicity by 44% (P < 0.05). Black raspberry followed closely, with tumor volume diminished by > 69% (P < 0.005) and tumor multiplicity by 37% (P = 0.07). Blueberry showed a reduction (40%) only in tumor volume. This is the first report showing the significant efficacy of both ellagic acid and berries in the prevention of solely estrogen-induced mammary tumors.

Berries as chemopreventive dietary constituents--a mechanistic approach with the ApcMin/+ mouse

         (Mutanen, Pajari et al. 2008) Download

Berries contain a number of compounds that are proposed to have anticarcinogenic properties. We wanted to see if pure ellagic acid, natural ellagitannins and three wild berries have any effect on the adenoma formation in Apc- mutated Min/+ mice. Min/+ mice were fed high-fat AIN93-G diets containing 10% (w/w) freeze-dried bilberry (Vaccinium myrtillus), lingonberry (Vaccinium vitis-idaea), cloudberry (Rubus chamaemorus), cloudberry seeds or cloudberry pulp or pure ellagic acid at 1564 mg/kg for 10 weeks. beta-Catenin and cyclin D1 protein levels in the adenomas and in the normal-appearing mucosa were determined by Western blotting and immunohistochemistry. Early changes in gene expression in the normal-appearing mucosa were analyzed by Affymetrix microarrays. Three wild berries significantly reduced tumour number (15-30%, p < 0.05), and cloudberry and lingonberry also reduced tumour size by over 60% (p < 0.01). Cloudberry resulted in decreased levels of nuclear beta-catenin and cyclin D1 and lingonberry in the level of cyclin D1 in the large adenomas (p < 0.05). Affymetrix microarrays revealed changes in genes implicated in colon carcinogenesis, including the decreased expression of the adenosine deaminase, ecto-5f-nucleotidase and PGE2 receptor subtype EP4. Ellagic acid had no effect on the number or size of adenomas in the distal or total small intestine but it increased adenoma size in the duodenum when compared with the control diet (p < 0.05). Neither cloudberry seed nor pulp had any effect on the adenoma formation. Berries seem to have great potential as a source of chemopreventive components.


Berry phenolics: antimicrobial properties and mechanisms of action against severe human pathogens

            (Nohynek, Alakomi et al. 2006) Download

Antimicrobial activity and mechanisms of phenolic extracts of 12 Nordic berries were studied against selected human pathogenic microbes. The most sensitive bacteria on berry phenolics were Helicobacter pylori and Bacillus cereus. Campylobacter jejuni and Candida albicans were inhibited only with phenolic extracts of cloudberry, raspberry, and strawberry, which all were rich in ellagitannins. Cloudberry extract gave strong microbicidic effects on the basis of plate count with all studied strains. However, fluorescence staining of liquid cultures of virulent Salmonella showed viable cells not detectable by plate count adhering to cloudberry extract, whereas Staphylococcus aureus cells adhered to berry extracts were dead on the basis of their fluorescence and plate count. Phenolic extracts of cloudberry and raspberry disintegrated the outer membrane of examined Salmonella strains as indicated by 1-N-phenylnaphthylamine (NPN) uptake increase and analysis of liberation of [14C]galactose- lipopolysaccharide. Gallic acid effectively permeabilized the tested Salmonella strains, and significant increase in the NPN uptake was recorded. The stability of berry phenolics and their antimicrobial activity in berries stored frozen for a year were examined using Escherichia coli and nonvirulent Salmonella enterica sv. Typhimurium. The amount of phenolic compounds decreased in all berries, but their antimicrobial activity was not influenced accordingly. Cloudberry, in particular, showed constantly strong antimicrobial activity during the storage.

Bioactive berry compounds-novel tools against human pathogens

            (Puupponen-Pimia, Nohynek et al. 2005) Download

Berry fruits are rich sources of bioactive compounds, such as phenolics and organic acids, which have antimicrobial activities against human pathogens. Among different berries and berry phenolics, cranberry, cloudberry, raspberry, strawberry and bilberry especially possess clear antimicrobial effects against, e.g. Salmonella and Staphylococcus. Complex phenolic polymers, like ellagitannins, are strong antibacterial agents present in cloudberry and raspberry. Several mechanisms of action in the growth inhibition of bacteria are involved, such as destabilisation of cytoplasmic membrane, permeabilisation of plasma membrane, inhibition of extracellular microbial enzymes, direct actions on microbial metabolism and deprivation of the substrates required for microbial growth. Antimicrobial activity of berries may also be related to antiadherence of bacteria to epithelial cells, which is a prerequisite for colonisation and infection of many pathogens. Antimicrobial berry compounds may have important applications in the future as natural antimicrobial agents for food industry as well as for medicine. Some of the novel approaches are discussed.

The action of berry phenolics against human intestinal pathogens

            (Puupponen-Pimia, Nohynek et al. 2005) Download

Phenolic compounds present in berries selectively inhibit the growth of human gastrointestinal pathogens. Especially cranberry, cloudberry, raspberry, strawberry and bilberry possess clear antimicrobial effects against e.g. salmonella and staphylococcus. Complex phenolic polymers, such as ellagitannins, are strong antibacterial agents present in cloudberry, raspberry and strawberry. Berry phenolics seem to affect the growth of different bacterial species with different mechanisms. Adherence of bacteria to epithelial surfaces is a prerequisite for colonization and infection of many pathogens. Antimicrobial activity of berries may also be related to anti-adherence activity of the berries. Utilization of enzymes in berry processing increases the amount of phenolics and antimicrobial activity of the berry products. Antimicrobial berry compounds are likely to have many important applications in the future as natural antimicrobial agents for food industry as well as for medicine.

Blackberry, black raspberry, blueberry, cranberry, red raspberry, and strawberry extracts inhibit growth and stimulate apoptosis of human cancer cells in vitro

            (Seeram, Adams et al. 2006) Download

Berry fruits are widely consumed in our diet and have attracted much attention due to their potential human health benefits. Berries contain a diverse range of phytochemicals with biological properties such as antioxidant, anticancer, anti-neurodegerative, and anti-inflammatory activities. In the current study, extracts of six popularly consumed berries--blackberry, black raspberry, blueberry, cranberry, red raspberry and strawberry--were evaluated for their phenolic constituents using high performance liquid chromatography with ultraviolet (HPLC-UV) and electrospray ionization mass spectrometry (LC-ESI-MS) detection. The major classes of berry phenolics were anthocyanins, flavonols, flavanols, ellagitannins, gallotannins, proanthocyanidins, and phenolic acids. The berry extracts were evaluated for their ability to inhibit the growth of human oral (KB, CAL-27), breast (MCF-7), colon (HT-29, HCT116), and prostate (LNCaP) tumor cell lines at concentrations ranging from 25 to 200 micro g/mL. With increasing concentration of berry extract, increasing inhibition of cell proliferation in all of the cell lines were observed, with different degrees of potency between cell lines. The berry extracts were also evaluated for their ability to stimulate apoptosis of the COX-2 expressing colon cancer cell line, HT-29. Black raspberry and strawberry extracts showed the most significant pro-apoptotic effects against this cell line. The data provided by the current study and from other laboratories warrants further investigation into the chemopreventive and chemotherapeutic effects of berries using in vivo models.

Bioactive compounds and health-promoting properties of berry fruits: a review

         (Szajdek and Borowska 2008) Download

This study characterizes biologically active compounds of berry fruits, including non-nutritive compounds such as phenolic compounds, including anthocyanins, phenolic acids, stilbens and tannins, as well as nutritive compounds such as carotenoids and vitamin C. It discusses the biological activity of those compounds, in particular their antioxidant properties and the resulting health benefits.


References

Aiyer, H. S. and R. C. Gupta (2010). "Berries and ellagic acid prevent estrogen-induced mammary tumorigenesis by modulating enzymes of estrogen metabolism." Cancer Prev Res (Phila) 3(6): 727-37.

Aiyer, H. S., C. Srinivasan, et al. (2008). "Dietary berries and ellagic acid diminish estrogen-mediated mammary tumorigenesis in ACI rats." Nutr Cancer 60(2): 227-34.

Mutanen, M., A. M. Pajari, et al. (2008). "Berries as chemopreventive dietary constituents--a mechanistic approach with the ApcMin/+ mouse." Asia Pac J Clin Nutr 17 Suppl 1: 123-5.

Nohynek, L. J., H. L. Alakomi, et al. (2006). "Berry phenolics: antimicrobial properties and mechanisms of action against severe human pathogens." Nutr Cancer 54(1): 18-32.

Puupponen-Pimia, R., L. Nohynek, et al. (2005). "Bioactive berry compounds-novel tools against human pathogens." Appl Microbiol Biotechnol 67(1): 8-18.

Puupponen-Pimia, R., L. Nohynek, et al. (2005). "The action of berry phenolics against human intestinal pathogens." Biofactors 23(4): 243-51.

Seeram, N. P., L. S. Adams, et al. (2006). "Blackberry, black raspberry, blueberry, cranberry, red raspberry, and strawberry extracts inhibit growth and stimulate apoptosis of human cancer cells in vitro." J Agric Food Chem 54(25): 9329-39.

Szajdek, A. and E. J. Borowska (2008). "Bioactive compounds and health-promoting properties of berry fruits: a review." Plant Foods Hum Nutr 63(4): 147-56.