Compositions and Biological Activities of Pomegranate Peel Polyphenols Extracted by Different Solvents

Abstract

Pomegranate peel extract (PPE), which is abundant in polyphenols, holds immerse prospects for the treatment of airway infection. In this study, water and ethanol of 30%, 50%, and 80% were used to prepare PPE. A total of 18 phenols belonging to 8 categories of polyphenols were identified in PPE by HPLC-MS/MS. The PPE from the four extraction solvents possessed different antioxidant, antibacterial, and anti-inflammatory activities. Principal component analysis revealed that though total flavonoids (TFs), total polyphenols (TPs), and total tannins (TTs) were responsible for the reducing power of PPE, only TFs contributed to the effect of PPE in inhibiting lipid membrane peroxidation. TPs, TTs, and punicalagin were positively correlated with the antibacterial strength against S. aureus while TTs alone contributed to the inhibition of methicillin-resistant S. aureus, implying the crucial role of TT in suppressing bacteria. Meanwhile, TTs was associated with the prevention of IL-6 release. The PPE with higher contents of TPs, TTs, and punicalagin had a weaker capacity to decrease nitric oxide secretion. PPE of 30% ethanol gained the highest integrated score due to its stronger antioxidant, antibacterial, and anti-inflammatory activities. It is a suitable candidate for the therapy of respiratory tract infection.

Changes in Polyphenols and Antioxidant Properties of Pomegranate Peels Fermented by Urolithin A-Producing Streptococcus thermophilus FUA329

“…3 Several types of recent research have demonstrated that pomegranate peels are rich in polyphenols, including phenolic acids (e.g., ellagic acid (EA), gallic acid, and hydroxycinnamic acid) and flavonoids (flavones, flavanones, isoflavones, anthocyanidins, and flavanols). 4,5 This spectrum of bioactive compounds exhibits antioxidant, 6 anti-inflammatory, 7 antimicrobial, 8 and anti-infective 9 properties. EA, a highly polar macromolecule, is predominantly present as ellagitannins (ETs) in pomegranate peels.…”

“…Pomegranate ( Punica granatum L.) is a deciduous shrub or small tree extensively grown in Iran, America, and China . Several types of recent research have demonstrated that pomegranate peels are rich in polyphenols, including phenolic acids (e.g., ellagic acid (EA), gallic acid, and hydroxycinnamic acid) and flavonoids (flavones, flavanones, isoflavones, anthocyanidins, and flavanols). , This spectrum of bioactive compounds exhibits antioxidant, anti-inflammatory, antimicrobial, and anti-infective properties.…”