Pomegranate: Red-Hot Fruit

Pomegranates have been cultivated since ancient times, but it is only recently that their health-promoting properties have come to the attention of the American public. “Pomegranate is becoming very popular and has many health benefits that have been excessively studied,” said Jeff Van Drunen, president of Van Drunen Farms. “Pomegranate has strong antioxidant activity due to its polyphenol content and ellagitannin content.”

Studies have focused on the ability of pomegranate juice and its compounds to address cardiovascular health and prevent carcinogenesis. One study conducted at the Rambam Medical Center in Haifa, Israel, involved 10 atherosclerotic patients given pomegranate juice for one year, and up to three years.¹ Patients taking pomegranate juice showed a significant reduction in LDL oxidative susceptibility and an increase in total antioxidant status; further, consumption of pomegranate juice appears to reduce systolic blood pressure and carotid intima-media thickness. Pomegranate juice was also found in a Iranian study of Type II diabetic patients to significantly reduce LDL and total cholesterol values.² And a study in mice found pomegranate juice was able to reduce the progression of atherosclerosis, while also increasing endothelial nitric oxide synthase expression.³

In relation to chemoprevention, in vitro work suggests both pomegranate juice polyphenols and pomegranate seed oil have the ability to reduce the number of lesions in a breast cancer model.⁴ Additional in vitro studies found ellagic acid, punicic acid, caffeic acid and luteolin all individually inhibited invasion of human PC-3 prostate cancer cells, and showed a supradditive inhibition when combined.⁵ And pomegranate fruit extract was also shown to protect cells from the adverse effects of UVB radiation by inhibiting modulations of certain cytokines and pathways.⁶

In the scientific community, there has been some discussion as to whether the beneficial health effects of pomegranate fruit and juice can be specifically attributed to its flavonoid compounds. Researchers at the University of California, Los Angeles, evaluated punicalagin, ellagic acid, a standardized total pomegranate tannin extract and pomegranate juice for their in vitro antioxidant, antiproliferative and apoptotic effects.⁷ Pomegranate juice showed the greatest antiproliferative activity as well as higher antioxidant activity compared to the isolated compounds or the standardized extract, leading the researchers to suggest there is chemical synergy among multiple compounds in the pomegranate juice. Further studies in humans suggest that ellagic acid found in human plasma after consumption of pomegranate juice may be due to its release from the ellagitannins,⁸ and that the metabolites of punicalagin and ellagic acid produced in the gut may produce the systemic biological effects of the pomegranate juice.⁹

These studies have raised questions about the issue of standardization in pomegranate extracts. At this time, some are standardizing to ellagic acid while others are focusing on specific compounds. Cyvex Nutrition provides its PomActiv™ standardized to 70 percent ellagic acid, while Geni Herbs standardizes its PomElla™ to punicalagin, an active ellagitannin specific to pomegranate, which can hydrolyze into ellagic acid. Scott Rosenbush, business manager of botanicals with P.L. Thomas, said standardizing to the ellagitannins or punicalagins focuses on the primary phytochemicals in pomegranate.

Because the pomegranate ingredients are relatively new in the market, there are formulation challenges associated with their use, according to some suppliers. “It is challenging to make highly concentrated pomegranate ingredients and maintain the integrity of the product from a nutritional standpoint,” Van Drunen said. “In formulating with a dry powder, other than a slightly astringent flavor, pomegranate is relatively easy to formulate. As with other polyphenols, it is important to keep pH low in liquid systems and to avoid heating the product excessively after it is in the final product.”

In addition, there is a growing number of branded pomegranate ingredients, which may help draw in consumers, if the products are backed by specific scientific research. “The usage of branded, novel ingredients may help differentiate finished products at retail,” confirmed Blake Ebersole, marketing coordinator with Geni Herbs. “In addition, formulators should look at targeting specific health needs, even though there are several different marketing angles companies could take.”

 References

1. Aviram M et al. "Pomegranate juice consumption for 3 years by patients with carotid artery stenosis reduces common carotid intima-media thickness, blood pressure and LDL oxidation." Clin Nutr. 23, 3:423-33, 2004. www.harcourt-international.com/journals/clnu

2. Esmailzadeh A et al. "Concentrated pomegranate juice improves lipid profiles in diabetic patients with hyperlipidemia." J Med Food. 7, 3:305-8, 2004. www.liebertpub.com

3. de Nigris F et al. "Beneficial effects of pomegranate juice on oxidation-sensitive genes and endothelial nitric oxide synthase activity at sites of perturbed shear stress." Proc Natl Acad Sci USA. 102, 13:4896-901, 2005. www.pnas.org

4. Mehta Re, Lansky EP. "Breast cancer chemopreventive properties of pomegranate (Punica granatum) fruit extracts in a mouse mammary organ culture." Eur J Cancer Prev. 13, 4:345-8, 2004.

5. Lansky EP et al. "Pomegranate (Punica granatum) pure chemicals show possible synergistic inhibition of human PC-3 prostate cancer cell invasion across Matrigel." Invest New Drugs. 23, 2:121-2, 2005.

6. Afaq F et al. "Pomegranate fruit extract modulates UV-B-mediated phosphorylation of mitogen-activated protein kinases and activation of nuclear factor kappa B in normal human epidermal keratinocytes." Photochem Photobiol. 81, 1:38-45, 2005.

7. Seeram NP et al. "In vitro antiproliferative, apoptotic and antioxidant activities of punicalagin, ellagic acid and a total pomegranate tannin extract are enhanced in combination with other polyphenols as found in pomegranate juice." J Nutr Biochem. 16, 6:360-7, 2005. www.elsevier.com/locate/jnutbio

8. Seeram NP, Lee R, Heber D. "Bioavailability of ellagic acid in human plasma after consumption of ellagitannins from pomegranate (Punica granatum L.) juice." Clin Chim Acta. 348, 1-2:63-8, 2004. www.sciencedirect.com/science/journal/00098981

9. Cerda B et al. "The potent in vitro antioxidant ellagitannins from pomegranate juice are metabolized into bioavailable but poor antioxidant hydroxyl-6H-dibenzopyran-6-one derivatives by the colonic microflora of healthy humans." Eur J Nutr. 43, 4:205-20, 2004. http://link.springer.de/link/service/journals/00394/