Preventive and Prophylactic Mechanisms of Action of Pomegranate Bioactive Constituents
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Hindawi Publishing Corporation Evidence-Based Complementary and Alternative Medicine Volume 2013, Article ID 789764, 18 pages http://dx.doi.org/10.1155/2013/789764 Review Article Preventive and Prophylactic Mechanisms of Action of Pomegranate Bioactive Constituents Monica Viladomiu,1,2 Raquel Hontecillas,1,2 Pinyi Lu,1,2 and Josep Bassaganya-Riera1,2,3 1 Nutritional Immunology and Molecular Medicine Laboratory, Virginia Bioinformatics Institute, Virginia Tech, Blacksburg, VA 24060, USA 2 Center for Modeling Immunity to Enteric Pathogens, Virginia Bioinformatics Institute, Virginia Tech, Blacksburg, VA 24060, USA 3 Department of Biomedical Sciences and Pathobiology, Virginia-Maryland Regional College of Veterinary Medicine, Virginia Tech, Blacksburg, VA 24061, USA Correspondence should be addressed to Josep Bassaganya-Riera; [email protected] Received 29 November 2012; Accepted 20 March 2013 Academic Editor: Edwin L. Cooper Copyright © 2013 Monica Viladomiu et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Pomegranate fruit presents strong anti-inflammatory, antioxidant, antiobesity, and antitumoral properties, thus leading to an increased popularity as a functional food and nutraceutical source since ancient times. It can be divided into three parts: seeds, peel, and juice, all of which seem to have medicinal benefits. Several studies investigate its bioactive components as a means to associate them with a specific beneficial effect and develop future products and therapeutic applications. Many beneficial effects are related to the presence of ellagic acid, ellagitannins (including punicalagins), punicic acid and other fatty acids, flavonoids, anthocyanidins, anthocyanins, estrogenic flavonols, and flavones, which seem to be its most therapeutically beneficial components. However, the synergistic action of the pomegranate constituents appears to be superior when compared to individual constituents. Promising results have been obtained for the treatment of certain diseases including obesity, insulin resistance, intestinal inflammation, and cancer. Although moderate consumption of pomegranate does not result in adverse effects, future studies are needed to assess safety and potential interactions with drugs that may alter the bioavailability of bioactive constituents of pomegranate as well as drugs. The aim of this review is to summarize the health effects and mechanisms of action of pomegranate extracts in chronic inflammatory diseases. 1. Introduction respectively, and the peels, which include the mentioned inner network of membranes [1]withdistinctchemical Pomegranate (Punica granatum), an ancient fruit-bearing compositions and potential medical benefits. deciduousshrub,isthepredominantmemberoftwospecies Pomegranate extracts have been used since ancient times comprising the Punicaceae family [1]. It is a native of the to treat several conditions including parasitic and microbial HimalayasinnorthernIndia,butithasbeencultivatedand infections, diarrhea, ulcers, aphthae, hemorrhage, and res- naturalized throughout the Middle East, the entire European piratory complications [3, 4]. Modern applications include Mediterranean region, the drier parts of southeast Asia, hormone replacement therapy and oral hygiene as well northern and tropical Africa, and to some extent the United as the treatment immune suppression and cardiovascular States, specifically California and Arizona2 [ ]. Pomegranate’s complications [5]. Moreover, other therapeutic properties fruit is a large berry characterized by the presence of thin such as antitumor, anti-inflammatory, antiviral, antibacterial, membranes in its interior, which allow the suspension of antidiarrheal, and antiobesity are currently under inves- numerous arils, each surrounded by juice-containing sacs. tigation. Although pomegranate has been consumed and The fruit can be divided into three parts: the seeds and the used as a medicinal food in the Middle East for thousands juice, which represent about 3 and 30% of the fruit weight, of years, it has recently gained popularity in the United 2 Evidence-Based Complementary and Alternative Medicine States [6]. The high antioxidant activity of pomegranate can be hydrolyzed to ellagic acid, a natural phenol with high when compared to other fruits and antioxidant beverages, antioxidant activity, thus prolonging the release of this acid along with its anti-inflammatory and antiobesity proper- into the blood [8]. Antioxidants are important since they ties, has increased the interest in investigating its potential have several important biological properties such as anti- nutraceutical and functional food applications. The number inflammatory and antiaging protection against cholesterol of scientific publications on pomegranate and its health- and atherosclerosis [12]. promoting benefits has increased significantly in the last Pomegranate juice is a rich source of polyphenols, tan- decade. A PubMed search on November 23, 2012, retrieves nins, anthocyanins, including vitamin C, vitamin E, coen- 677 publications related to pomegranate, 619 of which have zyme Q10, and lipoic acid [13]. Its main antioxidative com- beenpublishedwithinthelasttenyearsand425inthelast pounds are anthocyanins and ellagic acid derivatives, which five. Moreover, several pomegranate-containing products, are the main constituents of the juice, giving the fruit its including 100% juices, pomegranate-containing beverages, color [7]. Moreover, anthocyanins have been associated with liquid and powdered polyphenolic extracts of pomegranate, prevention of cardiovascular disease, obesity, and diabetes and skin care products containing pomegranate extracts or [14]. Some differences regarding the phenolic composition seed oils, have been recently introduced in the United States are found between natural and commercial juices as well as market and are being advertised for their beneficial health between juices obtained from the arils alone or from the effects [6]. Therefore, studying the bioactive components of whole fruit [7]. Nevertheless, pomegranate juice is still the pomegranate and linking them with specific mechanisms of main source for pomegranate ingestion, and its antioxidant action and health effects holds promise for future therapeutic levels are greater than in other natural juices [15, 16]. development of pomegranate-derived natural products. The Although pomegranate seeds, which represent about 3% aimofthisreviewistosummarizethehealtheffectsand of the fruit weight, have a low polyphenol content and in vitro mechanisms of action of pomegranate extracts in chronic antioxidant capacity, they contain other components that may inflammatory diseases. contribute to pomegranate’s health benefits [10, 17]. They are a rich source of lipids, and their oil, which constitutes 12–20% 2. Chemical Composition of Pomegranate of total seed weight, contains a unique fatty acid profile char- acterized by high concentration of fatty acids such as linoleic Over the last decade, there has been significant progress acid (LA) and linolenic acid (LN), as well as other lipids in investigating the mechanisms of action of pomegranate including punicic, oleic, stearic, -eleostearic, -eleostearic, components in health and disease. Extracts of all the different catalpic, gadoleic, arachidic, behenic, and palmitic acids LN parts of the fruit seem to have medicinal benefits [1]. Inter- (Table 1). Interestingly, punicic acid, which is a conjugated estingly, recent studies report that even the bark, roots, and isomer unique to pomegranate oil, constitutes 70–76% of the leaves of the pomegranate plant also have therapeutic prop- seed oil. Moreover, seed oil also contains minor amounts of erties [7]. The goal of most of the recent pomegranate studies other conjugated trienes such as eleostearic acid and catalpic is to identify its therapeutic constituents. Ellagic acid, ellag- acid [13]. Other minor components are sterols, steroids, itannins (including punicalagins), punicic acid, flavonoids, and cerebrosides in the seed oil [8, 18]andproteins,fibers, anthocyanidins, anthocyanins, estrogenic flavonols, and vitamins, and minerals in the whole seed [13]. flavones appear to be the most therapeutically beneficial The relationship between the chemical composition of pomegranate components [8], specially ellagitannins, which pomegranate and its respective therapeutic effects is still release ellagic acid when hydrolyzed. Tables 1, 2, 3,and4 summarize the chemical composition for each of the different not fully understood. However, significant progress has been parts of the pomegranate fruit. made in the last decade in the establishment and iden- The pomegranate peels make up about 60% of the fruit, tification of chemicals responsible for certain pharmaco- and they are rich in many compounds such as phenolics, logical mechanisms. Although ellagic acid, which presents flavonoids, ellagitannins (including punicalagins), proantho- both antioxidant [19] and anticarcinogenic [20]proper- cyanidin compounds, complex polysaccharides, and many ties, is thought to be the main compound responsible for minerals including potassium, nitrogen, calcium, magne- pomegranate health beneficial effects, recent studies suggest sium, phosphorus, and sodium [2]. However, its biologi- that the synergistic action of several pomegranate con- cal properties are mainly associated