Diet Supplementation with Pomegranate Peel Improves Embryonic Survival in a Mouse Model of Early Pregnancy Loss

Pomegranate peel attenuates dextran sulfate sodium-induced lipid peroxidation in rat small intestine by enhancing the glutathione/glutathione disulfide redox potential

BACKGROUND

The peel of the pomegranate fruit is rich in polyphenols with antioxidant properties. We investigated the preventive effect of pomegranate peel (PP) powder against dextran sulfate sodium (DSS)-induced lipid peroxidation in the small intestine of rats. Rats were allocated to four groups: CONT group, fed a standard rodent diet; DSS group, fed a standard rodent diet and treated with DSS; as well as PP1%+DSS and PP5%+DSS groups, fed a standard rodent diet supplemented with either 1% or 5% of PP powder and treated with DSS. Rats of the four groups consumed their diets for 25 days. Lipid peroxidation was determined by measuring malondialdehyde (MDA) concentrations in plasma and MDA contents in the small intestine and liver. Glutathione/glutathione disulfide (GSH/GSSG) redox status and antioxidant enzyme activities were determined in the small intestine and liver.

RESULTS

MDA content was higher (P < 0.001) in the small intestines of the DSS group compared to the CONT group. MDA content was reduced (P < 0.001) in the small intestines of the PP1%+DSS and PP5%+DSS groups compared to the DSS group. GSH contents and GSH/GSSG ratios were higher (P < 0.001) in the small intestines of the PP5%+DSS group compared to the CONT, DSS and PP1%+DSS groups.

CONCLUSION

The present study demonstrates that PP powder protects the small intestine against DSS-induced lipid peroxidation by enhancing the GSH/GSSG redox potential. Powder of PP is a promising agricultural by-product containing a mixture of bioactive polyphenols that can be used for the production of functional foods aimed at the prevention of oxidative stress-induced small intestine pathogenesis. © 2021 Society of Chemical Industry.

Effect of Solvent Extraction and Blanching Pre-Treatment on Phytochemical, Antioxidant Properties, Enzyme Inactivation and Antibacterial Activities of ‘Wonderful’ Pomegranate Peel Extracts

‘Wonderful’ pomegranate (Punica granatum L.) peel is rich in phytochemicals which are responsible for its strong antioxidant and antimicrobial activities, but it has low economic value as it is mainly discarded, causing an environmental waste management problem. To examine the best processing regime for pomegranate peel wastes, different solvents (ethanol, methanol and acetone) at various concentrations (50%, 70% and 100%) and blanching at 60, 80 and 100 °C for 1, 3 and 5 min, for each temperature, were tested. Ethanol at 70% (v/v) provided the highest extract yield, total phenolic and total tannin content at 29.46%, 10.61 ± 0.15, and 0.76 ± 0.02 mg GAE/g DM, respectively. Antioxidant activity using the 2,2 diphenyl-1-picryl hydrazyl assay (DPPH), ferric-reducing antioxidant power assay (FRAP) and 2,2-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid assay (ABTS) were reported at 243.97 ± 2.43, 478.04 ± 73.98 and 718.79 ± 2.42 µmol Trolox/g DM, respectively. A blanching temperature of 80 °C for 3 min led to the highest extract that had a total phenolic content of 12.22 ± 0.08 mg GAE/g DM and total tannin content of 1.06 ± 0.06 mg GAE/g DM. This extract also exhibited the best antioxidant activity for the DPPH, FRAP and ABTS assays. Two blanching temperatures, 80 or 100 °C, significantly reduced polyphenol oxidase and peroxidase activities (p < 0.05). Although blanched peel extracts showed a broad-spectrum activity against test bacteria, blanching at 80 °C for 3 or 5 min was most effective. Hot water blanching is thus a suitable environmentally friendly post-harvesting processing method for pomegranate peels that are intended for use as extracts in value-added products with good antioxidant and antibacterial effects.