Polyphenolic Composition, Antioxidant and Antiproliferative Activity of Edible and Inedible Parts of Cultivated and Wild Growing Pomegranate (Punica granatum L.)

Research background. The aim of this study was to determine and compare the antioxidant and antiproliferative activities of juices and extracts of the peel, aril and membrane of the cultivated and wild growing pomegranate fruits. Experimental approach. The contents of total phenols, total flavonoids, total flavonols, total flavan-3-ols, and total anthocyanins were determined spectrophotometrically. Individual phenolics were quantified by HPLC. Antioxidant activity was detected by DPPH and ABTS test, and neutralization of hydroxyl radical, while in vitro antiproliferative activity by sulforhodamine B (SRB) assay. Results and conclusions. Total phenols were statistically the highest in wild pomegranate peel extract (WPPE) and amounted 340.92 mg GAE/g (p<0.05), while the content of total flavonoids was the highest in cultivated pomegranate peel extract (CPPE) and amounted 31.84 mg QE/g (p<0.05). The WPPE sample showed the highest antioxidant activity with respect to free DPPH and ABTS radicals. The CPPE and CPME (cultivated pomegranate peel and membrane extracts, respectively) samples showed almost identical and the strongest effect on hydroxyl-radical inhibition (41.24 μg/mL and 41.23 μg/mL, respectively). The WPPE sample showed the strongest effect on the growth inhibition of all tested tumor cell lines compared to all other samples. Novelty and scientific contribution. In this study, bioactivity of different parts of cultivated and wild pomegranates were determined and compared. In the available literature, the individual antioxidant and antiproliferative activity of only some parts of pomegranate fruit were studied. In this work, all parts of the pomegranate fruit were investigated, including the membrane of the pomegranate, which was barely analyzed in other works. Also, wild pomegranate is less investigated in previous studies. Future research should be focused on in vivo studies of obtained pomegranate samples.