Pomegranate: Its Health and Biomedical Potential

Diet and lifestyle have long been recognized as important modifiers of health status. Modern scientific methods are being used to uncover, demystify, and validate the benefits of dietary constituents in health promotion. Likewise, many different foods are currently being studied for their role in the management of numerous disorders and conditions ranging from metabolic and inflammatory disorders to cardiovas-cular disease and cancer. Indeed, our best medicines may ultimately turn out to be botanicals, sourced from the 150,000 to 200,000 edible plant species on earth. These compounds are simply awaiting discovery and development. The concept of functional foods is evolving with insights into the mechanisms of action of a number of bioactive compounds found in foods. In this regard, this special issue focuses its attention on the emerging science of the pomegranate and its rich store of bioactive phytochemicals. The pomegranate's ability to combat oxidative stress, augment the activity of nitric oxide, and modulate inflam-matory pathways serves as the scientific basis for much of its recently discovered health benefits. As an example, a balance between free radicals and antioxidants is necessary for proper physiological function. If free radicals overwhelm the body's ability to regulate them, a condition known as oxidative stress ensues. Downstream, free radicals adversely alter lipid, protein, and DNA within cells, contributing to the etiology of a number of common chronic diseases and conditions associated with aging. The health benefits of pomegranate juice and extracts is derived from a spectrum of bioactive agents. In addition to the unique family of polyphe-nols in the pomegranate called punicalagins, pomegranate phytochemicals include anthocyanins, flavanols, and a seed oil which can be converted to conjugated linoleic acid. Among fruits, the hydrolysable tannin called punicalagin is uniquely found in the pomegranate. This is the largest polyphenol antioxidant with a molecular weight of over 1000 Daltons. These large molecules are hydrolyzed in the intestine and release ellagic acid into the bloodstream. Punicalagin, punicalin, gallagic acid, and ellagic acid account for the majority of the ellagitannins. The gut bacteria convert these ellagitannins into urolithins which are small molecules with antioxidant and other biological effects. Interestingly, the relevance of newly identified compounds to the mechanisms of action underlying the benefits of pomegranate juice and extracts has become an important path for future exploration and scientific investigation. To this end, purified extracts have proven to be valuable tools to explore and understand mechanisms of action of pomegranate juice. …