Currently pomegranate is grown in various parts of the world, although it originated in Iran, India, China and the Mediterranean region in 3000 BC. Its production and consumption continue to increase due to its taste and nutrition, and statistics show that the global production of this fruit was approximately 3.8 million tons in 2017. Particularly Pomegranate peel is a source of various bioactive compounds such as polyphenols, dietary fiber, vitamins and minerals, all of which have a variety of biological activities and health benefits, such as antioxidants, anti-inflammatories, anti-carcinogens.
Since antiquity, pomegranate peels have been used as folk remedies, due to the various beneficial compounds. In general, the peels have a higher amount of bioactive compounds when compared to the juice and seeds. Among the The main bioactive compounds can be mentioned polyphenols and dietary fiber.
In this context, the amount of total phenolic compounds is between 18 and 510 mg/g of dry matter in the pomegranate bark, differing by species, extraction solvents and extraction methods. The main phenolic substances among them are tannins, flavonoids and phenolic acids. For more, dietary fiber is the most abundant component of pomegranate peel it may cover from 33 to 62% of the total. In this way, pomegranate peels are valuable sources of dietary fiber, which can be used as a natural source, with good physicochemical and functional properties.
Phenolic Compounds
Tannins may have antioxidant activity due to hydroxyl groups of polyphenols, which can reduce the content of free radicals. In addition, the catechol’s hydroxyl groups in complex tannins and condensates give them the ability to chelate iron and transition metals. The literature shows that tannins can also exert a antibacterial activity through mechanisms involving inhibition of enzyme activity, precipitation of membrane proteins and depletion of metal ions.
On the other hand, flavonoids also have antioxidant activity., which is determined by its structural characteristics and substitution properties. In view of this, due to their high antioxidant capacity, flavonoids are often called phytoestrogens, which can reduce the incidence of cancers involved with hormones. Also, the Phenolic acids have an antibacterial action and their mechanism is associated with the fact that the transmembrane diffusion of these phenolic acids can result in cytoplasmic acidification, which may cause cell death in some cases.
Pomegranate Peel and Antioxidant Functions
Antioxidant compounds acquired from food can significantly reduce the adverse effects of reactive oxygen and nitrogen species on normal physiological functions in humans. With this, studies show the ability of pomegranate to act as this type of compound. For example, a study looked at the antioxidant capacity of aqueous extracts of pomegranate by-products and observed that it had a total phenolic content of 134.79 mg gallic acid equivalent (GAEs)/g of extracts. Thus, presenting a potential to become raw material for pharmaceutical formulations.
In addition, pomegranate peel extracts have been shown to reduce levels of thiobarbituric acid-reactive substances, oxidized low-density lipoprotein lipid peroxidation, and oxidative biomarkers associated with cardiovascular risk in healthy individuals, exhibiting potential antioxidant activity.
Pomegranate Bark and Anti-Inflammatory Functions
In inflammation several inflammatory mediators can be observed at the site of injury, among them we can mention chemokines, cytokines, vasoactive amines, eicosanoids and products of the cascade of protein hydrolysis. Therefore, in an animal model the anti-inflammatory properties of pomegranate were observed in rheumatoid arthritis after treatment with 13.6 mg/kg of pomegranate extract, which was shown to be potentially beneficial for decreasing interleukin-6 (IL-6) and interleukin-1 beta (IL-β), consequently decreasing the incidence of arthritis. Similarly, in a study in patients with rheumatoid arthritis, disease activity was significantly reduced after 8 weeks of supplementation with pomegranate peel extracts.
In addition, the literature also shows that in obese volunteers, pomegranate peel extracts exerted anti-inflammatory effects significantly reducing inflammatory markers such as malondialdehyde (MDA), IL-6, and hypersensitive C-reactive protein (hs-CRP).
Pomegranate Bark and Antibacterial Functions
The antibacterial potential of pomegranate can be attributed to phenolic compounds, with the potential to prevent or treat infections. Briefly, this is result of its ability to precipitate membrane proteins and inhibit enzymatic activity, leading to bacterial death and exerting antibacterial effects. Studies show that absorption of pomegranate peel extracts effectively inhibited Listeria monocytogenes, Staphylococcus aureus, Escherichia coli and Yersinia pestis in small bowel colitis.
Clinical practice
Despite the limitations of articles associating pomegranate and its possible physiological functions, this fruit presents a potential therapeutic use of potentially beneficial effects by improving the biomarkers of specific diseases. The actual effects of clinical application require further studies in the general population through randomized, well-designed controlled trials. Despite this, pomegranate can be a natural dietary source of dietary fiber and various phenolic compounds.
Bibliographic references
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Pomegranate article and bioactive compounds
: Mo Y, Ma J, Gao W, et al. Pomegranate Peel as a Source of Bioactive Compounds: A Mini Review on Their Physiological Functions. Frontiers in Nutrition. 2022;9. doi:https://doi.org/10.3389/fnut.2022.887113
