Potential of phenolic compounds from pomegranate (Punica granatum L.) by-product with significant antioxidant and therapeutic effects: A narrative review

The wealth of epidemiological evidence in the scientific world underscores the possibility that a plant-based diet can reduce the prevalence of common diseases such as diabetes, cardiovascular disease, cancer, and stroke. The therapeutic effects of plant sources are partly explained by phenolic secondary metabolites or polyphenolic compounds. Therefore, polyphenolic compounds, which are widely distributed in plants, are of great interest for the development of effective specific drugs with antioxidant and anti-inflammatory effects. Moreover, polyphenol compounds have no harmful effects due to their natural biocompatibility and safety. Numerous studies have highlighted the potential of some industrial food wastes from plant material processing, including apple peels and mashed potatoes, grape skins, tomato and carrot peels, pomegranate peels and seeds, and many others. These byproducts are considered low-cost sources of natural biological compounds, including antioxidants, which have beneficial effects on human health.The polyphenol complex of pomegranate peel (Punica granatum L.), which makes up half of the pomegranate fruit, has more pronounced antioxidant and anti-inflammatory properties than other parts. And the most important active components of pomegranate peel, which are found only in this plant, are punicalagin, followed by ellagic acid and gallic acid. It is known that these polyphenolic compounds of pomegranate peel have the most pronounced therapeutic effect. Several studies have shown the protective effect of ellagic acid, punicalagin, against oxidative stress damage caused by free radicals. The potential of pomegranate peel as an antioxidant and therapeutic component in various biological systems is high, according to scientific sources.However, despite extensive research in recent years, a review of sources has shown that there is insufficient evidence to support the therapeutic effects of polyphenolic compounds from pomegranate peels. The role of pomegranate peel polyphenolic compounds, including flavonoids, as antioxidants in various biological systems also requires further research. Of particular importance are the mechanisms by which antioxidants influence the cellular response against oxidative stress. The purpose of this review was to report our current knowledge of plant polyphenolic compounds and their classification, and to evaluate the potential of phenolic compounds from pomegranate peels with significant antioxidant and therapeutic effects.     

Effect of lecithin nanoliposome or soybean lecithin supplemented by pomegranate extract on post-thaw flow cytometric,microscopic and oxidative parameters in ram semen

This investigation was carried out to study the effect of soybean lecithin 1.5% (wt/vol) (0, 2.5, 5 and 7.5 mg l⁻¹ pomegranate extract (PE)) or PE-loaded lecithin nanoliposome (0, 2.5, 5 and 7.5 mg l⁻¹) to Tris-based extender. Sperm motility (CASA), viability, membrane integrity (HOS test), abnormalities, mitochondrial activity, apoptosis status, lipid peroxidation, total antioxidant capacity (TAC)) and antioxidant activities (GPX, SOD) were investigated following freeze-thawing. No significant differences were detected in motility parameters, viability, membrane integrity, and mitochondria activity after thawing sperm between soybean lecithin and lecithin nanoliposomes. It was shown that PE5 significantly improved sperm total and progressive motility, membrane integrity, viability, mitochondria activity, TAC and reduced lipid peroxidation (malondialdehyde concentration). Moreover, the percentage of apoptotic sperm in PE5 extenders was significantly the lowest among other treatments. Sperm abnormalities, SOD and GPX were not affected by the antioxidant supplements. For apoptotic status, no differences were observed between soybean lecithin and lecithin nanoliposome. We showed that lecithin nanoliposome extender can be a beneficial alternative extender to protect ram sperm during cryopreservation without any adverse effects. It was also observed that regarding pomegranate concentration, PE5 can improve the quality of ram semen after thawing.     

Punica granatum waste to ethanol valorisation employing optimized levels of saccharification and fermentation

Pomegranate peels (PPW) as municipal waste is inexpensive biomass that could be a renewable source of sugars particularly rich in hemicellulosic contents. The subsequent conversion of available sugars in PPW can provide prospective strategy for cost-effective bioenergy production. In this study, an experimental setup based on CCD was implemented with the aim of bioconversion of biomass into bioethanol. The factors considered were Hydrochloric acid concentration (X₁), the hydrolysis temperature (X₂) and time (X₃) for optimization with dilute Hydrochloric acid (HCl) saccharification. The present study investigates the optimised level of bioethanol synthesis from acid pre-treated PPW explained by RSM. Subsequently, three yeasts viz. Saccharomyces cerevisiae K7, Metschnikowia sp. Y31 and M. cibodasensis Y34 were utilized for fermentation of acid hydrolysed and detoxified feed stocks. Optimum values of reducing sugars 48.02 ± 0.02 (gL^?1) and total carbohydrates 205.88 ± 0.13 (gL^?1) were found when PPW was hydrolyzed with 1% HCl concentration at 100?C of temperature for 30 min. Later on, fermentation of PPWH after detoxification with 2.5% activated charcoal. The significant ethanol (g ethanol/g of reducing sugars) yields after fermentation with Metschnikowia sp. Y31 and M. cibodasensis Y34 found to be 0.40 ± 0.03 on day 5 and 0.41 ± 0.02 on last day of experiment correspondingly. Saccharomyces cerevisiae K7 also produce maximum ethanol 0.40 ± 0.00 on last day of incubation utilizing the PPWH. The bioconversion of commonly available PPW into bioethanol as emphasize in this study could be a hopeful expectation and also cost-effective to meet today energy crisis.     

Exercise training combined with antioxidant supplementation prevents the antiproliferative activity of their single treatment in prostate cancer through inhibition of redox adaptation

In preclinical models, exercise training (ET) or pomegranate juice (PJ) prevents prostate cancer progression. Here, we hypothesized that physical exercise combined with antioxidants could induce synergistic effects through oxidative stress modulation. Forty male Copenhagen rats with prostate tumors were divided into four groups: control, PJ, ET, and PJ+ET. Rats from the PJ group consumed 750 µl of PJ daily, rats from the ET group ran on a treadmill 5 days per week, and PJ+ET rats received the combined treatment. Each week, tumor growth was evaluated. After 4 weeks of treatment, the rats were euthanized and blood, muscles, and tumors were collected. Tumor Ki67, extracellular signal-regulated kinase (ERK) activation, Bcl-2 expression, and enzymatic and nonenzymatic antioxidant defenses, as well as oxidative stress markers (oxidized base, lipid peroxidation, protein carbonylation), were measured. PJ or ET significantly decreased prostate tumor proliferation (Ki67 staining, p<0.05) through the modulation of ERK phosphorylation, whereas the combination of treatments did not limit cancer progression. PJ significantly reduced Bcl-2 expression in tumors (p<0.05) and the combination of PJ and ET prevented this effect. PJ or ET increased enzymatic antioxidant defenses in muscle, PJ increased nonenzymatic antioxidant defenses in plasma and whole blood. In addition, PJ reduced TBARS and 8-oxodGuo levels in tumors as well as ET (p<0.05), whereas protein carbonyl levels were not affected by these two strategies. Paradoxically, association of PJ+ET did not increase antioxidant defenses and no reduction in oxidative stress markers was induced. Loading cancer cells with antioxidants blunts the positive effects of ET and interferes with important reactive oxygen species-mediated physiological processes such as antioxidant adaptations.     

Lactococcus lactis subsp. cremoris of Plant Origin Produces Antifungal Cyclo-(Leu-Pro) and Tetradecanoic Acid

The antifungal cyclo-depeptide and the fatty acid were isolated and purified from an indigenous strain of Lactococcus lactis subsp. cremoris. Maximal activity was observed at pH 5.5 and 6.5, and at 30 °C under stationary conditions, which was detected in the culture supernatant 8 h post-inoculation in MRS broth until 22 h. The activity of antifungal compounds in the culture supernatant was sensitive to pH and temperature; and was protease-resistant. The antifungal compounds were concentrated by freeze-drying and ultrafiltration with activity retained in 1 kDa filtrates indicating low molecular weight metabolites. The compounds were further extracted by using different solvents amongst which, ethyl acetate provided the highest recovery. Antifungal compounds were separated on a silica gel column into two active fractions that were revealed to be tetradecanoic acid and cyclo-(Leu-Pro), a cyclic dipeptide, by GC–MS. Herein, we describe and attribute the biocontrol potential of L. lactis subsp. cremoris to the low molecular weight antifungal compounds isolated, which is the first report of their isolation from this strain. The broad antifungal spectrum of this candidate advocates further exploration of its biocontrol potential in managing fungal infections in different food and feed systems.Supplementary InformationThe online version contains supplementary material available at 10.1007/s12088-020-00917-z.     

Kinetic profile and anti-diabetic potential of fermented Punica granatum juice using Lactobacillus casei

Lactobacillus casei NRRL-B-1922 was used to ferment whole fruit juice of Punica granatum. P. granatum which is also known as pomegranate could support the growth of L. casei even without nutrient supplementation. This can be seen from the maximum specific growth rate of the strain in shake flasks (0.08 h⁻¹) and stirred tank bioreactor (0.11 h⁻¹). Quercetin-3-glucoside was detected as the most abundant compound in the juice and its concentration increased up to 7.0 g/L at the maximum bacterial growth after 27-hs of fermentation in bioreactor. The results showed that the probioticated juice could have more than 80 % inhibition in dipeptidyl peptidase-4 (DPP4) assay. The glucose and fructose content were steadily reduced with the consumption rate of 0.51 g/L/h and 0.37 g/L/h, respectively in bioreactor. Therefore, the biotransformation of P. granatum juice by L. casei could increase the juice functionality by improving its inhibitory activity against DPP4.