Exploring the anti-cancer properties of pomegranate peel aqueous extract

The objective of this work is to evaluate the influence of pomegranate peel extract (PPE) in the behavior of breast cell lines (epithelial and tumor type) and related oxidative metabolism. Fruit-based functional foods have been the target of increasing scientific research for their physiological and pathophysiological properties. Pomegranate (Punica granatum) is a suitable example with both prophylactic and medicinal effects. MCF-7 cell line from tumor breast carcinoma, and MCF-10A cell line from normal epithelial mammary gland were used and subjected to different concentrations of PPE, ranging from 1 to 5 mM of gallic acid equivalents (GAE). Viability, proliferation, mobility, and cytotoxicity assays were performed along with the quantification of antioxidant enzymes, namely, catalase, superoxide dismutase (SOD) and reduced (GSH) and oxidized (GSSG) glutathione. We observed a decrease in viability and proliferation of MCF-7 cells, at higher concentrations of PPE, with no influence in epithelial cells. Interestingly, in a concentration-dependent manner, PPE triggered a significant decrease in migration on both cell lines, with a more pronounced effect in breast cancer cell line. Regarding antioxidant enzyme activity, on tumor cells higher concentrations of PPE decreased catalase activity and significantly increased SOD activity. Regarding GSH and GSSG, we observed different expression levels between MCF-7 and MCF-10A, with MCF-7 presenting lower levels compared to MCF-10A. GSH/GSSG ratio was notably higher in MCF-7 at 5 mM GAE. PPE exhibits anti-tumor effects without significantly affecting normal epithelial cells. Our work strengthens the potential antitumoral effect of PPE by reducing MCF-7 cell viability and proliferation through the imbalance of antioxidant enzymes.