Abstract

In this study, fruits of six soft cultivars of date palm (Phoenix dactylifera L.) commonly grown in Saravan (Sistan and Baluchistan province) were analysed for their antioxidant activities using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) methods. As well, total phenolic contents were evaluated by Folin-Ciocalteu reagent. The antioxidant power of fruits was in range of 236.82 to 579.54 μg/ml for various cultivars in DPPH assay. The antioxidant activity of samples was between 9.34 and 24.64 mg/ml in FRAP method. The total phenolic contents ranged from 2.980 to 8.454 mg gallic acid equivalents (GAE) per g dry weight (dw). The highest total phenolic contents was found at Zardan, with mean value of 8.454 ± 0.52 mg (GAE)/g dw and antioxidant activity was 24.64 ± 4.31 (mg/g dw) and 236.82 ± 11.14 (μg/ml) in FRAP and DPPH respectively. Radical scavenging correlation analyses indicated that there was a significant relationship (r=-0.974 and r=0.975, P<0.01) between both antioxidant methods and the total phenolic contents of various cultivars. The results of the experiments showed that fruits of date palm have high phenolic contents and suitable antioxidant potential. The antioxidant activity may be linked to phenolic contents of these cultivars but complementary investigations are suggested for determining active elements.

Key words: Antioxidants, date palm, 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP), total phenolic content.