Total phenolic contents and antioxidant activities of pomegranate peel, seed, leaf and flower

Abstract

Pomegranate (Punica granatum L.) is a nutrient dense food rich in beneficial phytochemicals. The aim of this study is to investigate and to determine antioxidant contents from local and highly consumed pomegranate variety called ‘Gabsi’. Peels, seeds, leaves and flowers were used to quantify total polyphenols, flavonoids, anthocyanins and hydrolysable tannins. Antioxidants contents were as follows: peel > flower > leaf > seed.Total polyphenols contents from peels were 85.60 ± 4.87 mg gallic acid equivalents per g dry weight (mg GAE/g DW), flavonoids (51.52 ± 8.14 mg rutin equivalents per g DW (mg RE/g DW), anthocyanins (102.2 ± 16.4 mg cyanidin-3-glucoside equivalents per g DW (mg CGE/g DW) and hydrolysable tannins (139.63 ± 4.25 mg tannic acid equivalent per g of DW (mg TAE/g DW). High free radical scavenging activity is reported in peels and flowers. Effective concentration at 50% (EC50) was 3.88 ± 0.33 µg/ml (peels) and 4.55 ± 0.97 µg/ml (flowers). Antioxidant capacity value was respectively 7.50 ± 0.83 Trolox equivalent antioxidant capacity (TEAC) mg/g DW (peels) and 6.39 ± 0.83 TEAC mg/g DW (flowers). Less important values were obtained from leaves (4.16 ± 1.35 TEAC mg/g DW) and seeds (1.10 ± 0.23 TEAC mg/g DW). Peels and flowers extract exhibited higher activities than seeds and leaves. All of these findings implied that bioactive compounds from pomegranate peels, flowers, leaves and seeds might be potential resources for the development of antioxidant function dietary foods. Extraction process of whole fruits may provide a commercial pomegranate juice with high antioxidants and consequently high usefulness antioxidant activities.   Key words: Pomegranate fruit and leaves extracts, polyphenols, flavonoids, anthocyanins, total tannins, antioxidant activity.