Antioxidant and anti-inflammatory effects of pomegranate peel extracts on bovine mammary epithelial cells BME-UV1

Abstract

Pomegranate peel extracts (PPE) were tested for the first time on BME-UV1, a valid cellular model to study the bovine mammary epithelial metabolism, to evaluate the effects on the oxidative stress and inflammatory status. Based on the statistical analysis of MTT data, PPE at 0.1, 1.0 and 10 μg/mL resulted not cytotoxic after 24 h, 48 h and 7 days of treatment. At the same concentrations, PPE induced a reduction of ROS production elicited by the addition of hydrogen peroxide or lipopolysaccharide evidencing an antioxidant effect confirmed also by a decrease of malondialdehyde. At 10 μg/mL, PPE reduced pro-inflammatory cytokines expressions showing an antiinflammatory effect on BME-UV1 treated with lipopolysaccharide. Although in vivo experiments are necessary, the results of this study are promising for future applications of PPE as feed supplement for dairy cattle, in particular around calving, when the animals are more subject to oxidative stress and inflammatory diseases.

Anti-Inflammatory Effects of Pomegranate Peel Extracts on In Vitro Human Intestinal Caco-2 Cells and Ex Vivo Porcine Colonic Tissue Explants

“…Both high-molecular and low-molecular weight phenolic compounds are present. High-molecular weight phenols were α- and β-punicalagin with 146.9 ± 1.465 mg/g and 266.3 ± 1.687 mg/g, respectively; gallic acid, ellagic acid and granatin B were low-molecular weight phenols found into PPE as minor components, as published previously [42,43].…”

“…While polyphenols are known to suppress inflammatory responses by supressing NF-κβ and mitogen-activated protein kinase (MAPK) signalling pathways [61], the underlying mechanism of action of these compounds are still not well understood. In our previous study, using a bovine mammary cell model [43], we observed anti-inflammatory activity by the same PPE used in the current study. We suggested that the observed anti-inflammatory activity of PPE could be related to a bioactive hydrolysable tannin, the punicalagin, that was present in high amounts (88.8%) in our extract in form of α and β isomers [43].…”

“…In our previous study, using a bovine mammary cell model [43], we observed anti-inflammatory activity by the same PPE used in the current study. We suggested that the observed anti-inflammatory activity of PPE could be related to a bioactive hydrolysable tannin, the punicalagin, that was present in high amounts (88.8%) in our extract in form of α and β isomers [43]. Additionally, in a previous study [62], punicalagin acted on NF-κβ pathway as a suppressor of the phosphorylation of IκBα and p65, thus inhibiting the activation of LPS induced NF-κβ.…”

“…Punica granatum L. (“Wonderful” variety) fruits were collected in Grosseto (Tuscany, Italy; Latitude: 42°45′46” N; Longitude: 11°06′33” E). The pomegranate peel extract (PPE) was prepared as already described [42,43,44]. Briefly, the crushed peel was treated with ultrapure water (weight/volume = 1/12) at 100 °C, the residue was filtered and water removed by lyophilisation using LYOVAC GT 2 (Leybold AJ-Cologne, Germany).…”

“…High Performance Liquid Chromatography (HPLC)/Diode Array Detection (DAD)/Electron Spray Ionisation (ESI)-Mass Spectrometry (MS) analyses were carried out using a HP-1100 liquid chromatograph equipped with a DAD detector, a HP 1100 MSD API-electrospray (Agilent Technologies-Palo Alto, CA, USA) detector, a Luna C18 column 250 × 4.60 mm, 5 µm (Phenomenex-Torrance, CA, USA) using the analytical conditions already described [44]. The Nuclear Magnetic Resonance (NMR) spectra were recorded using a 400 MHz nuclear magnetic resonance spectrometer Advance III (Bruker, Germany) [42,43].…”