Studies on Activity Guided Fractionation of Pomegranate Peel Extracts and Its Effect on Antidiabetic and Cardiovascular Protection Properties

Comprehensive review of opportunities and challenges of ethnomedicinal plants for managing type 2 diabetes

Diabetes mellitus is a prevalent metabolic disorder worldwide. A variety of antidiabetic medications have been developed to help manage blood glucose levels in diabetic patients, but adverse reactions and efficacy loss over time have spurred research into new therapeutic agents. In view of this, investigations into the antidiabetic effect of herbal products have been encouraged due to their potential availability, inexpensiveness, and relatively minimal side effects. This review explores the antidiabetic potentials of the eight most promising medicinal plants in terms of molecular mechanisms, phytochemistry, toxicology, and efficacy. These plant extracts have gone through clinical trials and demonstrated good control of blood glucose levels by increasing serum insulin levels, enhancing tissue glucose uptake, and/or decreasing intestinal glucose uptake. Yet, medicinal plants are far from being able to replace conventional antidiabetic drugs for patient management but they have the potential for further development if rigorous clinical trials on their mechanisms, delivery, and dose regimen are performed. To date, no study has been performed to isolate and characterize active compounds in these plant extracts, suggesting that further investigations in this area would be the next step to advance this field.

Phytochemical profile, nutritional composition of pomegranate peel and peel extract as a potential source of nutraceutical: A comprehensive review

The current study focuses on Punica granatum L. (pomegranate) peel and peel extract and their use as functional foods, food additives, or physiologically active constituents in nutraceutical formulations. The pomegranate peel extract is a good source of bioactive substances needed for the biological activity of the fruit, including phenolic acids, minerals, flavonoids (anthocyanins), and hydrolyzable tannins (gallic acid). The macromolecules found in pomegranate peel and peel extract have been recommended as substitutes for synthetic nutraceuticals, food additives, and chemo-preventive agents because of their well-known ethno-medical significance and chemical properties. Moreover, considering the promises for both their health-promoting activities and chemical properties, the dietary and nutraceutical significance of pomegranate peel and pomegranate peel extract appears to be underestimated. The present review article details their nutritional composition, phytochemical profile, food applications, nutraceutical action, and health benefits.

Phytochemical analysis, antioxidant, and antimicrobial activities of Jordanian Pomegranate peels

Pomegranate (Punica granatum) peels have shown numerous health benefits such as antioxidant, anti-inflammatory, and antimicrobial activities. These health activities are owed to the unique phytochemical components present in pomegranate peels. Variations in the pomegranate cultivar, geographical region, and extraction methods significantly affect the phytochemical composition and concentrations of pomegranate fruits and their peels, hence their health outcomes. Therefore, this study aimed to examine the phytochemical contents of pomegranate peels of Jordanian origin and their antioxidant and antimicrobial activities. Among the 6 extracts of pomegranate peels tested, the ethanol extract exhibited the highest total phenolic content (TPC = 297.70 ± 1.73 mg GAE/g DW), highest total flavonoids content (TFC = 116.08 ± 3.46 mg RE/g DW), highest hydrolyzable tannins (HT) contents (688.50 ± 3.54 mg TE/g DW). Whereas the highest condensed tannins (CT) content was found in both the ethanol (13.87 ± 0.58 mg CE/g DW) and methanol (13.84 ± 0.55 mg CE/g DW) extracts. For the antioxidant activities, the water extract of pomegranate peels displayed the highest inhibitory effect on DPPH radicals (9.43 ± 0.06 μmole TE/g DW), while for the ABTS+ assay the methanol and ethanol extracts exhibited the highest activities of 11.09 ± 0.02 and 11.09 ± 0.06 μmole TE/g DW, respectively. For the FRAP assay, the aqueous methanol extract exhibited the highest reducing activity (1.60 ± 0.09 mmole Fe (II)/g DW). As for the antimicrobial activities of various extracts of pomegranate peels, the highest antimicrobial activity against Micrococcus luteus was achieved by the ethanol extract (MIC = 6.25 mg/mL), whereas the lowest antimicrobial activity was observed against Candida krusei using the methanol extract (MIC = 100 mg/mL). These results indicate that pomegranate peels of Jordanian origin are rich in phytochemical content and exhibited strong antioxidant and antimicrobial activities making these agroindustrial by-products potential candidates for various medical applications and possible safe sources for important bioactive components.

The Modulatory Bioeffects of Pomegranate (Punica granatum L.) Polyphenols on Metabolic Disorders: Understanding Their Preventive Role against Metabolic Syndrome

Modern research achievements support the health-promoting effects of natural products and diets rich in polyphenols. Pomegranate (PG) (Punica granatum L.) contains a considerable number of bioactive compounds that exert a broad spectrum of beneficial biological activities, including antimicrobial, antidiabetic, antiobesity, and atheroprotective properties. In this context, the reviewed literature shows that PG intake might reduce insulin resistance, cytokine levels, redox gene expression, blood pressure elevation, vascular injuries, and lipoprotein oxidative modifications. The lipid parameter corrective capabilities of PG-ellagitannins have also been extensively reported to be significantly effective in reducing hyperlipidemia (TC, LDL-C, VLDL-C, and TAGs), while increasing plasma HDL-C concentrations and improving the TC/HDL-C and LDL-C/HDL-C ratios. The health benefits of pomegranate consumption seem to be acheived through the amelioration of adipose tissue endocrine function, fatty acid utilization, GLUT receptor expression, paraoxonase activity enhancement, and the modulation of PPAR and NF-κB. While the results from animal experiments are promising, human findings published in this field are inconsistent and are still limited in several aspects. The present review aims to discuss and provide a critical analysis of PG's bioeffects on the components of metabolic syndrome, type-2 diabetes, obesity, and dyslipidemia, as well as on certain cardiovascular-related diseases. Additionally, a brief overview of the pharmacokinetic properties, safety, and bioavailability of PG-ellagitannins is included.

Assessing the multitargeted antidiabetic potential of three pomegranate peel-specific metabolites: An in silico and pharmacokinetics study

Diabetes is a chronic metabolic disorder that occurs due to impaired secretion of insulin, insulin resistance, or both. Recent studies show that the antidiabetic drugs used to control hyperglycemic levels are associated with undesirable adverse effects. Therefore, developing a safe and effective medicine with antidiabetic potential is needed. In this context, in silico studies are considered a rapid, effectual, and cost-effective method in drug discovery procedures. It is evident from the literature that plant-based natural components have shown promising outcomes in drug development to alleviate various diseases and hence have diversified the screening of potential antidiabetic agents. Purposely, in the present study, an in silico approach was performed on three Punica granatum peel metabolites (punicalin, punicalagin, and ellagic acid). All these three compounds were docked against nine protein targets involved in glucose metabolism (GFAT, PTP1β, PPAR-ᵞ, TKIR, RBP4, α-amylase, α-glucosidase, GCK, and AQP-2). These three pomegranate-specific compounds demonstrated significant interactions with GFAT, PTP1β, PPAR-ᵞ, TKIR, RBP4, α-amylase, α-glucosidase, GCK, and AQP-2 protein targets. Specifically, punicalin, punicalagin, and ellagic acid revealed significant binding scores (-9.2, -9.3, -8.1, -9.1, -8.5, -11.3, -9.2, -9.5, -10.1 kcal/mol; -10, -9.9, -8.5, -8.9, -10.4, -9.0, -10.2, -9.4, -9.0 kcal/mol; and -8.1, -8.0, -8.0, -6.8, -8.7, -7.8, -8.3, -8.1, -8.1 kcal/mol, respectively), with nine protein targets mentioned above. Hence, punicalin, punicalagin, and ellagic acid can be promising candidates in drug discovery to manage diabetes. Furthermore, in vivo and clinical trials must be conducted to validate the outcomes of the current study.

Pomegranate (Punica granatum L.) peel extract ameliorates metabolic syndrome risk factors in patients with non-alcoholic fatty liver disease: a randomized double-blind clinical trial

INTRODUCTION

Non-alcoholic fatty liver disease (NAFLD) is a metabolic syndrome (MS)-related liver disorder that has an increasing prevalence. Thus, the aim of our study is to evaluate the effects of pomegranate peel extract (PP) supplementation on hepatic status and metabolic syndrome risk factors.

METHODS

In phase one, the hydro-alcoholic extraction of the peel of 750 kg of pomegranate (Punica granatum L.) was performed by the soaking method. Then, in phase two, NAFLD patients received 1500 mg of placebo (n = 37) or pomegranate peel capsules (n = 39) with a 500-kcal deficit diet for 8 weeks. Gastrointestinal intolerance, dietary intake, lipid and glycemic profiles, systolic and diastolic blood pressure, body composition, insulin resistance indexes, and elastography-evaluated NAFLD changes were followed.

RESULTS

The mean age of participants was 43.1 ± 8.6 years (51.3% female). Following the intervention, the mean body weight (mean changes: -5.10 ± 2.30 kg), waist circumference (-7.57 ± 2.97 cm), body mass index (-1.82 ± 0.85 kg/m2), body fat index (-1.49 ± 0.86), and trunk fat (- 3.93 ± 3.07%), systolic (-0.63 ± 0.29 cmHg) and diastolic (-0.39 ± 0.19 cmHg) blood pressure, total cholesterol (-10.51 ± 0.77 mg/dl), triglyceride (-16.02 ± 1.7 mg/dl), low-density lipoprotein cholesterol (-9.33 ± 6.66 mg/dl; all P < 0.001), fat free mass (- 0.92 ± 0.90 kg; P < 0.003), and fasting blood sugar (-5.28 ± 1.36 mg/dl; P = 0.02) decreased significantly in PP in contrast to the placebo group in the raw model and when adjusted for confounders. Also, high-density lipoprotein cholesterol (5.10 ± 0.36 mg/dl), liver steatosis and stiffness (- 0.30 ± 0.17 and - 0.72 ± 0.35 kPa, respectively, all P < 0.001) improved in the PP group. However, fasting insulin (P = 0.81) and homeostatic model assessment for insulin resistance (HOMA-IR) (P = 0.93) were not significantly different when comparing two groups during the study in the raw and even adjusted models.

CONCLUSION

In conclusion, 1500 mg pomegranate peel extract along with a weight-loss diet improved metabolic syndrome risk factors and reduced hepatic steatosis in patients with NAFLD after 8 weeks.

Effects of Punica granatum L. peel extract supplementation on body weight, cardiac function, and haematological and biochemical parameters in an animal model of metabolic syndrome

Introduction

Metabolic syndrome (MetS) is a cluster of pathological conditions well described in humans but still investigated insufficiently in animals. A novel approach in its management is the utilisation of nutrients from natural sources. Recent studies suggested that phenolic compounds from pomegranate peel could be a promising dietary intervention for MetS. This study evaluated the potency of polyphenol-rich pomegranate peel extract (EPP) in mitigating some MetS components in an animal model.

Material and Methods

Zucker diabetic fatty rats (with an fa/fa missense mutation in the Lepr leptin receptor gene) and their healthy counterparts (fa/+) as controls were fed a high-calorie diet to induce MetS and supplemented with EPP at two doses: 100 mg/kg body weight (b.w.) and 200 mg/kg b.w. The extract was administered for eight weeks. The rats' body weights were monitored twice per week, and blood samples were taken before EPP administration after four weeks and eight weeks of study. Echocardiography measurement was performed at the beginning and at the end of the study.

Results

The extract restrained the dynamic of weight gain. A cardioprotective effect of the highest dose of EPP supplementation was manifested in a relative decrease in heart rate and improved mid-fractional shortening, representing myocardial contractility. No improvement in fasting blood glucose or lipid profile was observed.

Conclusion

Pomegranate peel extract possesses beneficial health properties that could be useful in dietary intervention in MetS. However, its bioavailability still requires further investigation in clinical trials in humans and animals suffering from endocrine and metabolic disorders.

Nutritional importance and industrial uses of pomegranate peel: A critical review

Pomegranate (Punica granatum L.), commonly known as a seeded or granular apple, is a delectable fruit eaten worldwide. Pomegranate is one of the healthiest fruits, with a high concentration of phenolic compounds. Large quantities of byproducts, such as seeds and peels, are produced during the pomegranate juice extraction process, which causes disposal problems and environmental contamination. Pomegranate peel (PoP), which accounts for around 30%-40% of the fruit component, is a byproduct of the fruit juice manufacturing industry. PoP is a rich source of polyphenols including phenolic acids, tannins, and flavonoids, especially anthocyanin. These peels offer several functional and nutraceutical qualities owing to their bioactive ingredients, including lowering blood pressure, reducing oxidative stress, lowering cholesterol levels, and restoring heart health. PoPs have a variety of biological effects, including the ability to resist pathogenic microbes effectively, and used as an additive in various food applications. The current review focuses on the PoP's nutritional and practical attributes, as well as their functions as food additives and functional food preparations.

Anti-helminthic effect of Punica granatum peel extract on Trichinella spiralis worms and muscle larvae: in vitro and in vivo studies

Trichinella spiralis (T. spiralis) is a prevalent foodborne intestinal parasite in many developing countries. Albendazole (ABZ) is the drug of choice for treating trichinosis despite its several drawbacks as its week effect against encapsulated larvae, low bioavailability, and emerging drug resistance. As a result, new anthelmintic agents are required. This study aims to investigate the in vivo and in vitro effects of Punica granatum peels extract (PGPE) on intestinal and muscle phases of T. spiralis. The adult worms and larvae were isolated and cultured with different concentrations of PGPE ranging from 6.75 to 100 µg/ml and measuring the survival rate was done after 1, 3, 18, 24 and 48 h of incubation, followed by scanning electron microscopic (SEM) examination of isolated parasites. For the in vivo experiment, the infected animals were divided into two main groups: intestinal phase group and muscular phase group, each group was subdivided into; infected not treated, infected treated with PGPE, ABZ and combined PGPE and ABZ (6 mice in each). The drug effect was assessed by adults and larvae load. A significant increase in the percentage of dead adult parasite and muscle larvae cultured with PGPE with severe destruction and deformity of the tegument were observed with SEM. Also, a significant reduction of adult parasite number in the intestine and muscle larva number in the diaphragm of infected treated mice in comparison to the control group. This study proved that PGPE has a potential activity against trichinosis, particularly when combined with ABZ, and this could serve as a new agent in trichinosis therapy.

Pomegranate peel extract protects against the development of diabetic cardiomyopathy in rats by inhibiting pyroptosis and downregulating LncRNA-MALAT1

Background: Pyroptosis is an inflammatory programmed cell death accompanied by activation of inflammasomes and maturation of pro-inflammatory cytokines interleukin-1β (IL-1β) and IL-18. Pyroptosis is closely linked to the development of diabetic cardiomyopathy (DC). Pomegranate peel extract (PPE) exhibits a cardioprotective effect due to its antioxidant and anti-inflammatory properties. This study aimed to investigate the underlying mechanisms of the protective effect of PPE on the myocardium in a rat model of DC and determine the underlying molecular mechanism.

Methods: Type 1 diabetes (T1DM) was induced in rats by intraperitoneal injection of streptozotocin. The rats in the treated groups received (150 mg/kg) PPE orally and daily for 8 weeks. The effects on the survival rate, lipid profile, serum cardiac troponin-1, lipid peroxidation, and tissue fibrosis were assessed. Additionally, the expression of pyroptosis-related genes (NLRP3 and caspase-1) and lncRNA-MALAT1 in the heart tissue was determined. The PPE was analyzed using UPLC-MS/MS and NMR for characterizing the phytochemical content.

Results: Prophylactic treatment with PPE significantly ameliorated cardiac hypertrophy in the diabetic rats and increased the survival rate. Moreover, prophylactic treatment with PPE in the diabetic rats significantly improved the lipid profile, decreased serum cardiac troponin-1, and decreased lipid peroxidation in the myocardial tissue. Histopathological examination of the cardiac tissues showed a marked reduction in fibrosis (decrease in collagen volume and number of TGF-β-positive cells) and preservation of normal myocardial structures in the diabetic rats treated with PPE. There was a significant decrease in the expression of pyroptosis-related genes (NLRP3 and caspase-1) and lncRNA-MALAT1 in the heart tissue of the diabetic rats treated with PPE. In addition, the concentration of IL-1β and caspase-1 significantly decreased in the heart tissue of the same group. The protective effect of PPE on diabetic cardiomyopathy could be due to the inhibition of pyroptosis and downregulation of lncRNA-MALAT1. The phytochemical analysis of the PPE indicated that the major compounds were hexahydroxydiphenic acid glucoside, caffeoylquinic acid, gluconic acid, citric acid, gallic acid, and punicalagin.

Conclusion: PPE exhibited a cardioprotective potential in diabetic rats due to its unique antioxidant, anti-inflammatory, and antifibrotic properties and its ability to improve the lipid profile. The protective effect of PPE on DC could be due to the inhibition of the NLRP3/caspase-1/IL-1β signaling pathway and downregulation of lncRNA-MALAT1. PPE could be a promising therapy to protect against the development of DC, but further clinical studies are recommended.

The Therapeutic Alliance between Pomegranate and Health Emphasizing on Anticancer Properties

Pomegranate is a fruit bearing-plant that is well known for its medicinal properties. Pomegranate is a good source of phenolic acids, tannins, and flavonoids. Pomegranate juice and by-products have attracted the scientific interest due to their potential health benefits. Currently, the medical community has showed great interest in exploiting pomegranate potential as a protective agent against several human diseases including cancer. This is demonstrated by the fact that there are more than 800 reports in the literature reporting pomegranate's anticancer properties. This review is an update on the research outcomes of pomegranate's potential against different types of human diseases, emphasizing on cancer. In addition, perspectives of potential applications of pomegranate, as a natural additive aiming to improve the quality of animal products, are discussed.

Bioaffinity ultrafiltration coupled with HPLC-ESI-MS/MS for screening potential α-glucosidase inhibitors from pomegranate peel

Pomegranate peel (PoP) contains plenty of bioactive compounds and exhibits strong activity to prevent postprandial hyperglycaemia and improve diabetes mellitus. Presently, bioaffinity ultrafiltration coupled with high performance liquid chromatography-electrospray ionization mass spectrometry (HPLC-ESI-MS/MS) is employed to screen and identify the efficient α-glucosidase inhibitors in PoP and the detailed inhibitory mechanisms are further investigated. The results show that many substances, including ellagic acid, kaempferol, gallic acid, and resveratrol in PoP reveal strong activity to inhibit α-glucosidase and ellagic acid (EA) is screened as the most effective compound. Further research indicates that EA plays a competitive and reversible inhibition role against α-glucosidase with the value of Ki was 6.24 × 105 mol/L. EA also directly interacts with the amino acids of α-glucosidase mainly via van der Waals forces and hydrogen bonds, thereby, influencing the secondary structure and stability of α-glucosidase. Finally, the α-glucosidase inhibitory activity of EA is further confirmed to significantly reduce postprandial blood glucose in vivo.

Integrated biorefinery development for pomegranate peel: Prospects for the production of fuel, chemicals and bioactive molecules

Current experimental evidence has revealed that pomegranate peel is a significant source of essential bio compounds, and many of them can be transformed into valorized products. Pomegranate peel can also be used as feedstock to produce fuels and biochemicals. We herein review this pomegranate peel conversion technology and the prospective valorized product that can be synthesized from this frequently disposed fruit waste. The review also discusses its usage as a carbon substrate to synthesize bioactive compounds like phenolics, flavonoids and its use in enzyme biosynthesis. Based on reported experimental evidence, it is apparent that pomegranate peel has a large number of applications, and therefore, the development of an integrated biorefinery concept to use pomegranate peel will aid in effectively utilizing its significant advantages. The biorefinery method displays a promising approach for efficiently using pomegranate peel; nevertheless, further studies should be needed in this area.

Phytochemical Analysis, α-Glucosidase and α-Amylase Inhibitory Activities and Acute Toxicity Studies of Extracts from Pomegranate (Punica granatum) Bark, a Valuable Agro-Industrial By-Product

Punica granatum is a tree of the Punicaceae family which is widespread all over the world with several types of varieties. Its fruit juice is highly prized, whereas the bark, rich in in phytochemicals such as flavonoids, hydrolysable tannins, phenolic acids, and fatty acids, is regarded an agro-industrial waste. It is utilized in traditional medicine for its medicinal properties in the treatment and prevention of a variety of ailments. This study aims to extract and to separate the phytochemical compounds from the bark of P. granatum, to identify them and to study the inhibitory effect of its extracts against antidiabetic activity. First, we carried out successive hot extractions with solvents (chloroform, acetone, methanol, and water) of increasing polarity by the Soxhlet. Then, using both qualitative and quantitative phytochemical investigation, we were able to identify groups of chemicals that were present in all extracts. We identified the majority of the molecular structures of chemicals found in each extract using HPLC-DAD analysis. The inhibition against both intestinal α-glucosidase and pancreatic α-amylase enzymes by P. granatum extracts was used to evaluate their potential antidiabetic effect in vitro. Our results demonstrated the great potential of the acetone extract. Ellagic acid, (−)-catechin, vanillin and vanillic acid were proposed as the most active compounds by the correlation analysis, and their actions were confirmed through the calculation of their IC₅₀ and the determination of their inhibition mechanisms by molecular modelling. To summarize, these results showed that P. granatum bark, a natural agro-industrial by-product, may constitute a promising option for antidiabetic therapeutic therapy.

Amelioration of diabetes and its complications by Manilkara zapota (L) P. Royen fruit peel extract and its fractions in alloxan and STZ-NA induced diabetes in Wistar rats

Purpose

This study aims to evaluate the effects of Manilkara zapota (L) P. Royen fruit peel extract (EMZFP) and its fractions in ameliorating diabetes and its complications in alloxan and STZ-NA induced diabetes in Wistar rats.

Methods

Antidiabetic effects of EMZFP were assessed in alloxan (150 mg kg^-1) induced diabetes in differently grouped rats (n=6). Diabetic rats were treated with EMZFP 150, 300, and 600 mg kg^-1 while, glimepiride (0.09 mg kg^-1) was used as a reference standard. Treated animals were assessed for various biological parameters i.e. blood glucose, serum lipids, nephroprotective markers, cardiovascular risk indices, liver glycogen, neuropathy, body weight, and histopathology of kidneys. However, for evaluating antidiabetic effects of fractions (chloroform, acetone, ethyl acetate, and remaining ethanol fraction) of EMZFP, diabetes was induced by streptozotocin (60 mg kg^-1)-nicotinamide (120 mg kg^-1/ml) in differently grouped male rats (n=6). Diabetic rats were treated with EMZFP fractions 200 mg kg^-1 however; glibenclamide (10 mg kg^-1) was a reference standard and evaluated for blood glucose, serum lipids, cardiovascular risk indices, and diabetic neuropathy.

Results

EMZFP 300 and 600 mg kg^-1/day demonstrated significant antihyperglycemic effects with augmentation in glycogen content, perfection in serum lipid profile, cardiovascular risk indices, body weight enhancement, nephroprotective effects, beneficial in peripheral neuropathy, and histopathological evidence of reversal of glomerulosclerosis. EMZFP-Et and EMZFP-EA fractions depicted a significant improvement in blood glucose, serum lipid profile, cardiovascular risk indices, and peripheral neuropathy.

Conclusion

EMZFP and its Et and EA fractions ameliorated diabetes and its complications by improving glycemic control and associated biochemical alteration.

Highlights

• Manilkara Zapota (L.) P. Royen fruit peel 70% ethanolic extract exert antidiabetic effects• EMZFP significantly ameliorated diabetic biochemical parameters and its complications.• EMZFP-Et and EMZFP-EA fractions exert potential antihyperglycemic, hypolipidemic effects and significantly improved cardiovascular risk indices, and peripheral neuropathy.• Studied MZFP can be used as promising natural herbal source of antidiabetic principles.

Fabrication of chitosan-based food packaging film impregnated with turmeric essential oil (TEO)-loaded magnetic-silica nanocomposites for surimi preservation

Successful modification of chitosan (CS) film using magnetic-silica nanocomposite to encapsulate turmeric essential oil (TEO) obtained by super critical CO2 extraction for enhanced preservation of surimi was performed. TEO exhibited antioxidant and antibacterial activities against Bacillus cereus. The core magnetic nanoparticles (MNPs) were capped with porous silica (Si) to form core-shell nanocomposites, into which TEO was loaded with 75.24% encapsulation efficiency. The fabricated nanocomposite was characterized, blended with CS to cast a bionanocomposite active film and characterized for efficient impregnation of bionanocomposite. The physical and mechanical properties of film were significantly improved after adding MNPs/Si/TEO nanocomposite. Uncontrolled release of TEO from CS film resulted in bacterial growth after 6 days of storage whereas bionanocomposites exhibited a sustained release of TEO that controlled the microbial load from 4.0 log CFU/g to 2.78 log CFU/g over 14 days. The overall study demonstrated that the CS/MNPs/Si/TEO bionanocomposite film was efficient as a packaging material for prolonged shelf-life of surimi.

Punica granatum Peel Waste - An Underutilized Substrate of Therapeutic Potential: An Overview

India is the second largest consumer and producer of fruits globally. It leads to ample solid waste per year from fruit processing industries that have been proven hazardous to the surroundings. Punica granatum (Pomegranate) belongs to the Lythraceae subfamily Punicoideae, which exhibits immense nutritional properties and delicious flavoring components. The weight of this fruit mainly consists of peel, i.e., 50%, followed by 40% of arils and 10% of seeds. Thus, the major byproduct is peel that holds many valuable bioactive compounds in higher concentrations viz saponins, carotenoids, steroids, polyphenols, quercetin derivatives, caffeic acid, phenolic acids, flavonoids, ellagitannins, p-coumaric acid, chlorogenic acid, quinic acid, anthocyanidins, triterpenoids, glycosides, tannins, and many more. Consequently, it results in wideranging therapeutic applications, including antioxidative, anti-microbial, antihypertensive, anticarcinogenic, anti-genotoxic, anti-inflammatory, glucoregulation, cardio-protective, hepatoprotective and nephroprotective effects along with prebiotic potential. Considering their nutritional and therapeutic aspects, these peels can be used for many purposes rather than being disposed off. With a value-added approach, it is utilized in many food and non-food sectors. So, this review aims to explore the therapeutic potential of P. granatum peel and enlighten its diverse applications in the food industry.

Recovery of Bioactive Compounds from Pomegranate (Punica granatum L.) Peel Using Pressurized Liquid Extraction

Pressurized liquid extraction (PLE) is a clean and environmentally friendly alternative for the recovery of bioactive compounds from fruit by-products. Herein we focused on PLE for the extraction of bioactive compounds from pomegranate peel using a combination of pressurized water and ethanol. The main aim was to determine the optimal PLE conditions, i.e., ethanol percentage and process temperature, to obtain a pomegranate peel extract (PPE) with maximum total phenolic content (TPC), punicalagin content, and antimicrobial activity (AMA). The experimental design was conducted using a central composite design with axial points. Response surface methodology was applied to optimize the response variables using the desirability function. Multiple response optimization indicated a process temperature of 200 °C and ethanol of 77% as optimal conditions. The TPC and the punicalagin content of PPE-PLE obtained under optimal conditions were 164.3 ± 10.7 mg GAE/g DW and 17 ± 3.6 mg/g DW, respectively. Our findings support the efficacy of PLE on TPC recovery but not in punicalagin recovery. The AMA against S. aureus was 14 mm. The efficacy of PPE-PLE in food applications must continue to be studied in order to achieve adequate information on its potential for developing new food additives.

Pomegranate variety and pomegranate plant part, relevance from bioactive point of view: a review

Pomegranate (Punica granatum L.) belongs to the Punicaceae plant family. It is an important fruit due to its nutritional and medicinal properties. Pomegranates are widely distributed around the world and, therefore, have a broad genetic diversity, resulting in differences in their phytochemical composition. The scientific community has focused on the positive health effects of pomegranate as a whole, but the different varieties have rarely been compared according to their bioactive compounds and bioactivity. This review aims to provide a holistic overview of the current knowledge on the bioactivity of pomegranate trees, with an emphasis on differentiating both the varieties and the different plant parts. This review intends to provide a general and organized overview of the accumulated knowledge on pomegranates, the identification of the most bioactive varieties, their potential consumption pathways and seeks to provide knowledge on the present gaps to guide future research.

Antimicrobial Activity of Pomegranate Peel and Its Applications on Food Preservation

Pomegranate (Punica granatum L.) fruit is being cultivated since the civilization is known, and its production and consumption have been increased since the last century due to the scientific confirmation of its health benefits. Pomegranate fruits, fruit juice, its seeds, and peels are known to have higher contents of bioactive compounds, viz., phenolic acids, flavonoids, and hydrolysable tannins. The peels of pomegranate fruits are the major by-products produced during food processing of pomegranate enriched in antioxidants and broad-spectrum antimicrobial agents and can prevent food deterioration even. This health potential of pomegranate is known to vary significantly upon the varieties, growing conditions, cultivation practices, stages of the development, and the extraction methods. Herein, the biochemical composition of the pomegranate peel extract (PPE), its efficacy in food preservation, and antimicrobial activities are discussed to provide a comprehensive guide for farmers, food processing, and storage sectors and academia.

Fruit, vegetables, and mushrooms for the preparation of extracts with α-amylase and α-glucosidase inhibition properties: A review

The inhibition of the α-amylase and α-glucosidase activity facilitates the maintenance of circulating glucose levels by decreasing the rate of blood sugar absorption. Existing enzyme inhibitors such as acarbose, miglitol, and voglibose are used for inhibiting the activity of these enzymes, however, alternative solutions are required to avoid the side-effects of using these drugs. The current study aims to review recent evidence regarding the in vitro α-amylase and α-glucosidase inhibition activities of extracts derived from selected fruit, vegetables, and mushrooms. The mechanisms of action of the extracts involved in the inhibition of both enzymes are also presented and discussed. Compounds including flavonoids, phenolic acids, anthocyanins, saponins, carotenoids, terpenes, sugars, proteins, capsaicinoids, fatty acids, alkaloids have been shown to have α-amylase and α-glucosidase inhibition activities. Harvesting period, maturity stage, sample preparation, extraction technique, and solvent type are parameters that affect the α-amylase and α-glucosidase inhibition activities of the extracts.

Pomegranate Peel as Suitable Source of High-Added Value Bioactives: Tailored Functionalized Meat Products

In the last few years, the consumer's concern with the relationship between health and diet has led to the search of foods with functional properties beyond the nutritional. In this framework, the consumption of pomegranate has increased due to their sensorial attributes and remarkable amounts of bioactive compounds, which generate, at the same time, huge amounts of by-products. A search in the Scopus database for the last 10 years has revealed the rising interest in pomegranate peel (PP), the main residue from this fruit. The meat industry is a food sector that has had to search for new alternatives to substitute the use of synthetic preservatives by new natural additives, to extend the self-life and keep the quality attributes of their processed products. This review sets out the main bioactivities of PP extracts, and their incorporation in meat products is elaborated. PP is a good source of bioactive compounds, including phenolic acids, flavonoids and hydrolyzable tannins, which have beneficial health effects. It can be concluded that the reformulation of meat products with PP extracts is a suitable strategy for enhancing their technological characteristics, in addition to conferring functional properties that make them healthier and potentially more acceptable for the consumer.

Functional Foods and Bioactive Compounds: A Review of Its Possible Role on Weight Management and Obesity's Metabolic Consequences

Background: Weight management and obesity prevention is a basic aim of health organizations in order to decrease the prevalence of various metabolic disorders. The aim of the present review article was the evaluation of the possible role of functional foods and their bioactive compounds as alternative way to promote weight management and prevent obesity and its metabolic consequences. Methods: Approximately 100 articles were selected from Scopus, PubMed, Google Scholar, and Science Direct, by using relative key words, and based mainly on recent animal, clinical or epidemiological studies. Results: The literature review highlighted the possible effect of specific functional foods such as coffee, green tea, berries, nuts, olive oil, pomegranate, avocado, and ginger. Specific bioactive compounds of those foods—such as caffeine, catechins, gallic acid, anthocyanins, ascorbic acid, polyphenols, oleuropein, capsaicin, and quercetin—may contribute to weight management, obesity prevention, and obesity’s metabolic consequences. The possible mechanisms include effect on satiety, lipid absorption, fatty acids beta oxidation, stimulation of thermogenesis, etc. Conclusions: Functional foods, as part of a balanced diet, could be useful in the direction of weight management and decrease of obesity’s’ metabolic consequences. However, the scientific evidence is unclear and in most cases controversial and more clinical and epidemiological studies are needed in order to further investigate the mechanisms of their possible effect.

Pomegranate peel as phenolic compounds source: Advanced analytical strategies and practical use in meat products

The growing demand for natural food preservatives has promoted investigations on their application for preserving perishable foods. Consequently, the meat market is demanding natural antioxidants, free of synthetic additives and able to diminish the oxidation processes in high-fat meat and meat products. In this context, the present review discuss the development of healthier and shelf stable meat products by the successful use of pomegranate peel extracts containing phenolics as natural preservative agent in meat and meat products. This paper carries out an exhaustive review of the scientific literature on the main active phenolic compounds of pomegranate peel identified and quantified by advances in the separation sciences and spectrometry, and its biological activities evaluation. Moreover, the impact of pomegranate peel use on the quality and oxidative stability of meat products is also evaluated. As natural preservative, pomegranate peel phenolics could improve stored meat products quality, namely instrumental color retaining, limitaion of microflora growth, retardation of lipid and protein oxidation.

Phenolic profiles, antihyperglycemic, antihyperlipidemic, and antioxidant properties of pomegranate (Punica granatum) peel extract

This work is aimed to evaluate phenolics composition, and in vitro antioxidant activities of hydro-methanol pomegranate (Punica granatum L.) peel extract (MPE). In addition, the antihyperglycemic, hypolipidemic, and hepatoprotective effect of MPE in Wister albino rats was compared with standard drugs (glibenclamide and atorvastatin). Total phenolic content and total flavonoid contents in MPE (mg g^-1 ) accounted for 188.9 as GAE and 13.95 as QE, respectively. Phenolic and flavonoids compounds in MPE analyzed by HPLC and revealed the presence of 23 phenolic compounds and 20 flavonoid compounds. For in vivo experiment, 56 rats were distributed into 8 groups. Group 1 was the normal control, while group 2 contained rats orally administrated with 200 mg kg^-1 MPE daily. Group 3 contained diabetic rats (induced with a single dose of 100 mg/kg b.w. alloxan). Group 4 contained diabetic rats administered daily with 200 mg/kg MPE. Group 5 contained diabetic rats administered orally with a glibenclamide (standard drug for diabetic) at 10 mg/kg daily. Group 6 fed with high fat diet (HFD). Group 7 contained HFD-rats administered orally with 200 mg/kg MPE daily. Group 8 contained HFD-rats administered orally with atorvastatin (used to lower LDL-cholesterol (LDL-C) and fats and to raise HDL-cholesterol (HDL-C) in the blood) at 10 mg/kg daily. The study lasted for 56 days. Administration with MPE 200 mg/kg to both diabetic and hyperlipidemic rats significantly decreased blood glucose, HbA_1c , total lipid, total cholesterol, LDL-C, and very low density lipoprotein cholesterol levels, while increased high density lipoprotein cholesterol levels, as well as improved liver and kidney functions, compared with glibenclamide and atorvastatin effects. PRACTICAL APPLICATIONS: Pomegranate peel, constituted about 50% of fruit fresh weight, is rich in bioactive compounds with potent health-promoting activities. The results of the current study stated that MPE is rich in phenolics and flavonoids with powerful antioxidant potential. In addition, MPE showed antihyperglycemic and antihyperlipidemic activities due to the strong antiradical action via its antioxidant compounds. MPE enhanced liver and kidney functions when compared to standard drugs in diabetic and hyperlipidemic rats. MPC could be used as a natural material to develop diabetic and hyperlipidemic drugs.

An integrated green biorefinery approach towards simultaneous recovery of pectin and polyphenols coupled with bioethanol production from waste pomegranate peels

An integrated biorefinery, incorporating hydrothermal processing of waste pomegranate peels (WPP), was proposed for the acid and organic solvent-free simultaneous recovery of pectin and phenolics with bioethanol production. The hydrothermal treatment (HT) was optimized using Box-Behnken design and the maximum recovery of pectin (18.8-20.9%) and phenolics (10.6-11.8%) were obtained by hydrothermal treatment at 115 °C for 40 min with a liquid-solid ratio of 10. The WPP pectin was characterized by IR, ¹H NMR, and TGA which showed close similarity to commercial pectin. Depending on WPP cultivar type the degree of esterification, galacturonic acid content and molecular weight of pectin were in the range of 68-74%, 71-72%, and 131,137-141,538 Da, respectively. The recovered phenolics contained 57-60% punicalagin. Enzyme digestibility of WPP improved using HT with 177 g glucose produced per kg dry mass which was fermented to obtain 80 g ethanol with 88% of theoretical yield.

Vasculoprotective Effects of Pomegranate (Punica granatum L.)

Pomegranate (Punica granatum L.), one of the oldest known edible fruits, is nowadays broadly consumed throughout the world. Its fruits and seeds as well as other anatomical compartments (e.g., flowers and leaves) are rich in numerous bioactive compounds and therefore, the scientific interest in this plant has been constantly growing in recent years. It has been shown that pomegranate and its extracts exhibit potent antioxidative, antimicrobial, and anticarcinogenic properties. The present review summarizes some recent studies on pomegranate, highlighting mainly its vasculoprotective role attributed to the presence of hydrolyzable tannins ellagitannins and ellagic acid, as well as other compounds (e.g., anthocyanins and flavonoids). These in vitro and in vivo studies showed that substances derived from pomegranate reduce oxidative stress and platelet aggregation, diminish lipid uptake by macrophages, positively influence endothelial cell function, and are involved in blood pressure regulation. Clinical studies demonstrated that daily intake of pomegranate juice lessens hypertension and attenuates atherosclerosis in humans. Altogether, the reviewed studies point out the potential benefits of a broader use of pomegranate and its constituents as dietary supplements or as adjuvants in therapy of vascular diseases, such as hypertension, coronary artery disease, and peripheral artery disease.

Phenolic compounds as beneficial phytochemicals in pomegranate (Punica granatum L.) peel: A review

Pomegranate peel (PoP), a juice byproduct often considered as a waste, comprises nearly around 30-40% portion of the fruit. Phenolic compounds (one class of bioactive phytochemicals) are primarily concentrated in the peel portion of pomegranate fruit. In PoP, the main phenolic compounds reported in the literature include flavonoids (anthocyanins such as pelargonidin, delphinidin, cyanidin along with their derivatives and anthoxanthins such as catechin, epicatechin and quercetin), tannins (ellagitannins and ellagic acid derivatives such as punicalagin, punicalin and pedunculagin) and phenolic acids (such as chlorogenic, caffeic, syringic, sinapic, p-coumaric, ferulic, ellagic, gallic and cinnamic acid). It is generally accepted that phenolic compounds can be more efficiently recovered from PoP by improving the extraction efficiency. The curative relevance of these compounds has been mainly assessed by in vitro experimentation. Therefore, conclusive clinical trials of the phenolic compounds present in PoP are essential for correct validation of their health benefits.