Antioxidant Effect of Moroccan Pomegranate (Punica granatum L. Sefri Variety) Extracts Rich in Punicalagin against the Oxidative Stress Process

Abstract

Natural antioxidants products are widely distributed in food and medicinal plants. These natural antioxidants, especially polyphenols, exhibit a wide range of biological activities including anti-cancer, anti-inflammatory, and anti-atherosclerosis activities. Pomegranate (Punica granatum L.) is a rich source of polyphenolic components. The purpose of this study was to characterize the phenolic composition and flavonoids and anthocyanin content of different parts (peel and aril) of the Sefri variety of pomegranate. Our results showed that Peel extract was richer in these compounds than that of the Arils, especially in Punicalagin (A and B). DPPH free radical scavenging, reducing power (FRAP), β-carotene bleaching, and hydrogen peroxide scavenging assays revealed a greater dose-dependent activity of pomegranate peel phenolic extract (PPPE) compared to pomegranate aril phenolic extract (PAPE). PPPE was also more potent than PAPE concerning its ability to inhibit conjugated diene formation and to reduce α-tocopherol disappearance induced by CuSO4-mediated LDL peroxidation. Interestingly, both extracts (PPPE and PAPE) significantly inhibited lipid peroxidation and the formation of reactive oxygen species (ROS) in stressed J82 human bladder cancer cells. These results reflect the protective effects that this Moroccan variety of pomegranate can provide against the development of metabolic disorder, cancer, atherosclerosis, and cardiovascular disease. Given these properties, further studies should be undertaken to investigate possible applications of Sefri pomegranate extracts in the fields of food preservation and health supplements.

Keywords: J82 human bladder cell line; Punica granatum L.; antioxidant activity; low density lipoprotein (LDL); paraoxonase 1.

Figure 1

High-performance liquid chromatography-photodiode array (HPLC-PDA) chromatogram of bioactive molecules in (A): PPPE and (B): PAPE. The vertical red/blue lines correspond to the integration limits of each peak. Horizontal red lines correspond to peak detection threshold.

Figure 1

High-performance liquid chromatography-photodiode array (HPLC-PDA) chromatogram of bioactive molecules in (A): PPPE and (B): PAPE. The vertical red/blue lines correspond to the integration limits of each peak. Horizontal red lines correspond to peak detection threshold.

Figure 2

Effect of PPPE and PAPE on endogenous α-tocopherol disappearance during 4 h of CuSO₄-induced low-density lipoprotein (LDL) oxidation. Results are expressed as the means ± sem of at least three independent assays. *** p < 0.001, ** p < 0.01 and * p < 0.05 indicate significant differences compared to the control.

Figure 3

Pomegranate polyphenols improve PON1 activity. PON1 activity was measured in PPPE- or PAPE -enriched (80 µg/mL) plasma for 2 h. Results are expressed as the means ± sem of three independent assays. * p < 0.05, ** p < 0.01 and indicate significant differences compared to the control.

Figure 4

The extract of pomegranate peel and aril induces PON1 expression in Fu5AH cells. Fu5AH cells were cultured for 4 h in the presence (100 ug/mL) or absence of the extract of pomegranate’s peel or aril. The cells were washed and labelled with anti-PON1 mAbs. Expression of PON1 was determined by multi-color flow cytometry analysis in cells exposed or not to peels or arils extracts. Mean fluorescence intensities (MFI) values of FACS profiles are shown. Data are representative of three independent experiments. The asterisks indicate statistically significant differences determined by one-way ANOVA tests. *** p < 0.001 and **** p < 0.0001.

Figure 5

(A): Intracellular radical scavenging activity of PPPE and PAPE. J82 cells were treated with 100 or 200 μg/mL of PPPE or PAPE. Cells were labelled with 10 μmol/L DCFH-DA. The DCF fluorescence intensities were measured. The results are expressed as the means ± sem of more than three independent assays. *** p < 0.001 indicates a significant difference compared to the control. (B): Effects of PPPE and PAPE on TBARS levels in J82 cells. TBARS levels were assessed using a spectrophotometer. All values are expressed as the means ± sem of three independent assays. ** p < 0.01 and * p < 0.05 indicates a significant difference compared to the control (untreated cells).