Antioxidant properties of different cultivars of Portulaca oleracea

Methanolic extracts of six cultivars of Portulaca oleracea were analyzed for their total phenol content (TPC) using the Folin-Ciocal-teu method. The antioxidant activity was measured using the 1,1-diphenyl-2-picrylhydrazyl, ferric-reducing antioxidant power (FRA-P) and P-carotene bleaching (BCB) assays. The iodine titration method was used to determine the ascorbic acid content (AAC). The TPC of the cultivars of P. oleracea ranged from 127 +/- 13 to 478 +/- 45 mg GAE/100 g of fresh weight of plant. There was good correlation between the TPC value and its AEAC, IC50 and FRAP values (r(2) > 0.9) for all the cultivars. The AAC for the cultivars ranged from 38.5 +/- 10.6 to 73.0 +/- 17.5 mg/100 g. The TPC value of the common variety PO1, was the lowest compared to the ornamental cultivars (P02-PO6). The BCB assay showed that all cultivars were capable of inhibiting lipid peroxidation and the inhibition power did not correlate with TPC value. (c) 2006 Elsevier Ltd. All rights reserved.