Pomegranates: Ancient Roots to Modern Medicine by Navindra Seeram, Risa N. Schulman, and David Heber. Boca Raton, FL: CRC Press; 2006. Hardback; 244 pages. ISBN 0-84939812-6. $129.95.
Until recently, very little information was available regarding the chemistry, potential health benefits, and agricultural handling of pomegranates (Punica granatum, Lythraceae), although anecdotal reports of its cultivation and benefit have been propagated for millennia. The recent growing appreciation of the pomegranate as a functional fruit with many beneficial medicinal qualities has stimulated a significant level of research and public interest. Drs. Seeram, Schulman, and Heber have surveyed and presented the whole spectrum of interest surrounding the pomegranate in one precise and concise volume. This guide discusses in a wonderfully comprehensive and understandable manner the complex biochemistry of pomegranates and their varied health effects such as cardiovascular health, chemoprevention, and antimicrobial activity. The impact of the uniquely and naturally occurring estrogen (estrone) in pomegranate is also discussed, as well as the effects of optimizing plant growth and improving post-harvest biology and quality. The editors approached this book with the aim of exploring and comprehensively reporting on the biochemistry, health effects, and cultivation of this antioxidant polyphenol-rich fruit. Collectively, this handbook is a must-have reference for anyone interested in any aspect of pomegranate.
More than 100 different pomegranate phytochemicals are identified; however, the pomegranate is complex with thousands of phytochemicals including anthocyanins, ellagitannins and gallotannins, ellagic acid derivatives, catechins and procyanidins, flavonols, organic acids, fatty acids and triglycerides, sterols and terpenoids, and alkaloids, as well as many other compounds—all of which may be biologically active. The editors expertly and clearly describe, define, and lucidly illustrate how the different chemical groups are frequently composed of the same building blocks but in different combinations and numbers. For example, gallic acid occurs naturally but can dimerize to form ellagic acid. Ellagic acid can dimerize to form gallagic acid. Ellagic acid can combine with glucose to form the unique compounds punicalagin and punicalin. It is noteworthy that punicalagin is responsible for 50% of the antioxidant activity of pomegranate. The different combinations and polymers of the aforementioned form the large, diverse group of compounds known as polyphenols. The editors have enlisted numerous international experts to assist in clearly deciphering and conveying the complexity and beauty of pomegranate polyphenols in intellectually digestible fragments.
The antioxidant properties and bioavailability are also described to show that all parts of the pomegranate plant can exhibit antioxidant activity including the bark, stem, arils, whole fruit juice, and leaves. Dr. Micheal Aviram demonstrates that all pomegranate tree parts contain polyphenols and have relatively high antioxidant activity. In vitro laboratory, in vivo, and human studies are summarized to show that pomegranate polyphenols and their metabolites, including the urolithins, are in fact absorbed and can reach tissues to be protective against elements of many disease processes such as cardiovascular disease and cancer. Moreover, this work establishes the bioavailability and metabolism of pomegranate polyphenols in human studies, supporting a potentially potent protective role in human disease.
The health effects are clearly described with evidence supporting protection against myriad processes in cardiovascular disease and stroke, or cerebrovascular disease. In fact, dozens of mechanistic targets are identified from LDL to paraoxonase to macrophages to specific genes, etc. Collectively, this work extends the observations of Nobel Prize winner Dr. Louis Ignarro that pomegranate juice increases nitric oxide production in the endothelial cells of the vascular system, conferring protective effects against cardiovascular disease (e.g., having a slight vasodilating effect, thereby producing a slight hypotensive effect). Further information is given that clearly demonstrates the anticancer potential of pomegranate juice at many tissue sites and, in fact, specific mechanisms are also explored and reported for pomegranate juice and extract.
Regarding the extraordinary effort of Drs. Seeram, Schulman and Heber, it is indeed refreshing to read about the growing body of careful and in-depth scientific research being conducted on pomegranates to evaluate and confirm the beneficial effects. Probably the most compelling cancer study is the demonstration involving men with aggressive prostate cancer. When given 8 ounces of pomegranate juice (POM Wonderful, LLC) daily after treatment by surgery or radiation, there was a prolonged delay in prostate specific antigen (PSA) doubling time by over 4-fold. Moreover, pomegranate juice reduced the rate of PSA rise by 50% over only one year.
Chapters are also included to discuss the clear antimicrobial properties of pomegranate juice against bacteria and fungus, as well as extracts of the hull, fruit, pericarp, and seeds. A particularly interesting aspect of pomegranate is the presence of the unique fatty acid punicic acid in the seed. It also has the highest known botanical concentration of estrone, one of the three principal natural steroids.
Lastly, the commercialization of pomegranate as fresh fruit, beverages, and botanical extracts is discussed regarding the economic impact of all parts of the pomegranate. Discussion of the huge potential for use of pomegranate extracts in functional foods, cosmeceuticals, nutraceuticals, and botanical dietary supplements is discussed, outlining the global importance and interest by industry, academia, government, and the public. The need for commercial standardization is beautifully illustrated by the authors with an analysis of 7 commercial pomegranate botanical extracts demonstrating marked differences in composition and suggesting spiking with synthetic components.
The botanical description, cultural conditions, and genetic diversity are nicely summarized and then followed by an in depth discussion of the compositional changes during maturation and ripening, maturity and quality indices, and multiple comprehensive facets of post-harvest physiology. This is particularly relevant and timely for botanicals since these influences can affect pomegranate fruit and product quality. The latter continues with the effects of temperature, humidity, chilling, scalding, pathogens, and handling systems. Preparation for market and optimal storage conditions are also presented as a well-rounded survey of pomegranate horticulture.
As popularity and research regarding pomegranate preparations continue to increase, both as “functional foods” and dietary supplements, this book will no doubt become one of the primary references on this compelling functional fruit.
—Keith R. Martin, PhD, MTox Director, Nutrition Research POM Wonderful, LLC Los Angeles, CA