Antioxidant potential of selected underutilized fruit crop species grown in Sri Lanka

Lyophilized aqueous extracts of four underutilized fruit species namely <em>Diospyros discolor </em>(Velvet apple), <em>Pouteria campechiana </em>(Lavulu/Canistel), <em>Phylanthus acidus </em>(Mal-Nelli/Star gooseberry) and <em>Phyllanthus emblica </em>(Nelli/Indian gooseberry) were investigated for the antioxidant potential (AP) by 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, 2,2-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid (ABTS) assay and ferrous reducing antioxidant power (FRAP) assay. Total phenolic content (TPC) and total monomeric anthocyanin content (TMAC) were determined by Folin-Ciocalteu’s colorimetric assay and pH differential method, respectively. Vitamin C (VitC) content of fresh fruit was evaluated titrimertically and expressed as mg of ascorbic acid in 100 g of fresh weight (FW). The TPC and TMAC were expressed as mg of gallic acid equivalents (GAE)/100g FW and mg of cyanodin-3-glucoside (C3G)/100g FW. The measured parameters differed significantly among four fruit species. The values ranged between 84.42 – 1939.70 mg GAE/100g FW, 10.41 – 55.64 mg C3G/100g FW, 0.067 – 310.63 mg FW/ml, 9 – 81.29%, 238.25 – 2891.57 Fe²⁺μmol/100g FW and 17.12 – 523.14 mg/100g FW for TPC, TMAC, IC₅₀, RSA, FRAP and VitC, respectively. <em>Phyllanthus emblica </em>possessed highest values in all parameters while <em>Phyllanthus acidus </em>showed the lowest except in TPC. The lowest TPC was observed in <em>Diospyros discolor</em>. The extract of <em>Pouteria campechiana </em>also showed considerable amount of TPC (640 mg C3G/100g FW), RSA (76%) and VitC of 53 mg/ 100g. The results revealed that these underutilized fruit crops can be used as sources of natural antioxidants and vitamin C<em>.</em>