Antioxidant Potential of Pomegranate ( Punica granatum L.) Cultivars Grown in Sri Lanka

Abstract

The present study was carried out to determine the total phenolic content (TPC) and antioxidant potential of extracts obtained from aril of Sri Lankan cultivars Nayana, Daya, Nimali and Indian cultivar of pomegranate (Punica granatum L.). Total phenolic content was determined using Folin-Ciocalteu colorimetric method and expressed as mg gallic acid equivalents (GAE) per L of extract. Antioxidant potential of the fruit extracts was measured using DPPH radical scavenging and FRAP assays and β-carotene/linoleate model system. The total antioxidant capacity (TAC) was measured using ABTS radical. The TPC varied widely among cultivars from 1199 mg GAE/L of extract in Indian cultivar to 2390 mg GAE/L of extract in Daya. The Daya cultivar possessed the highest TPC, followed by Nayana, Nimali, and Indian cultivars. Despite the moderate TPC, Nayana showed the highest antioxidant potential as determined by all four methods (IC 50 value of 0.182 mg/mL, TAC of 93%, FRAP of 6.33 mol Fe (II)/L and 91% inhibition of oxidation of β-carotene). The TPC and antioxidant activity were not well correlated (0.21≤ r ≤ 0.68). The poor correlation may be attributable to the differential behaviour of phenolic constituents. Results revealed that the pomegranate can be categorized as a fruit with extremely high antioxidant potential.