Ongoing and potential novel trends of pomegranate fruit peel; a comprehensive review of its health benefits and future perspectives as nutraceutical

Abstract

Pomegranate is an ancient shrub, globally distributed nowadays. It has been used in the middle east as a medicinal food and traditional medicine for thousands of years.Pomegranate peel (PP) constitutes about 50% of the total fruit, however, it has been previously regarded as a waste. Recent research points to PP as a rich source of phenolics (e.g., ellagitannins, flavonoids, and anthocyanins), polysaccharides, in addition to its biotransformed metabolites viz. urolithins making it a valuable waste with promising pharmacological actions.Compared to the pulp and the juice, PP exhibited stronger antioxidant and antimicrobial activities. Besides, it inhibited inflammation in several conditions, including colitis, arthritis, hepatitis, contact dermatitis, and lung inflammation. Moreover, it displayed anti-osteoporosis, anti-hyperglycemic, antidiabetic, antihypertensive, vasculoprotective, hepatoprotective, neuroprotective, and immunomodulatory effects. Additionally, it was effective as a prebiotic and in obesity control, besides it promoted wound healing. Furthermore, PP demonstrated anticancer effects against different cancer types, for example, colon, liver, thyroid, uterine, breast, bladder, prostate, leukemia, and osteosarcoma. Despite PP safety, it may interfere with the metabolism of other drugs because it inhibits cytochromes (CYP) changing their bioavailability, effectiveness, and toxicity. PP biowaste valorization not only avoids against its environmental and economic burden but can also provide a promising platform to produce novel or improved nutraceuticals. This study provides a comprehensive overview of PP biological activities with the reported action mechanisms related to its phytochemicals and further biotransformed metabolites inside the body. Future research prospects to unravel the merits of such waste and optimize its use are discussed.Practical application: Pomegranate is widely distributed throughout the world.Although its peel was previously considered a waste, recent research regards it as a rich source of bioactive compounds with promising biological activities. Its recycling not only overcomes the bio-waste problems, but also provides a source of valuable compounds with several health benefits.

Punicalagin Protects against the Development of Methotrexate-Induced Hepatotoxicity in Mice via Activating Nrf2 Signaling and Decreasing Oxidative Stress, Inflammation, and Cell Death

“…It possesses high amounts of phenolic compounds, including hydrolyzable tannins, flavonol glucosides, phenolic acids, ellagic acid derivatives, and flavonoids in its various parts such as fruits, seeds, leaves, and peels [ 30 , 31 ]. Pomegranate is known for its potential health-promoting properties, including antioxidant, anti-inflammatory, anticancer, antihypertensive, antiatherosclerosis and antimicrobial activities [ 29 , 32 ]. Punicalagin (PU, C 48 H 28 O 30 ) is one of the major active pomegranate polyphenols possessing antioxidant and anti-inflammatory properties, among others [ 33 , 34 , 35 ].…”

Gas-Mediated Intestinal Microbiome Regulation Prompts the Methanol Extract of Schizonepetae Spica to Relieve Colitis

“…For example, pomegranate peel and its polyphenol-rich extract inhibit various inflammatory diseases, including ulcerative colitis. Its active ingredient urolithin A upregulates the epithelial tight junction protein by stimulating the aryl hydrocarbon receptor (AhR) nuclear factor-erythroid 2 related factor 2 (Nrf2)-dependent pathway, improving intestinal barrier function and inhibiting inflammation [ 2 , 6 ]. Therefore, dietary therapy may become a new strategy for treating ulcerative colitis.…”

Fruit Peels: Food Waste as a Valuable Source of Bioactive Natural Products for Drug Discovery

“…To the best of our knowledge no comprehensive review has been published about natural products which were isolated from fruit peels and our review mainly focus on the natural products which are purely isolated and their biological effects but not detected via mass techniques. Indeed, some minireviews have been published about the fruit peel crude extracts and biological activities or invidual reviews of fruit peels and their natural products [1,[5][6][7][8][9][10][11][12][13][14][15][16][17][18][19].…”