Polyphenolic contents and antioxidant activities of leaves of Phoenix dactylifera and flowers of Aloe vera

Abstract

The present study investigates the comparative antioxidant ability of the methanolic extract of Phoenix dactylifera's and methanolic and aqueous extracts of Aloe vera's Antioxidant ability was assessed by using the DPPH, FRAP, ABTS+ free-radical scavenging and hydroxyl radicals scavenging assays, Pro-oxidant effect was determined by Bleomycin-dependent DNA damage method. The total phenolic and flavonoid contents of the A. vera's flower and date leaves were also quantified. The total phenolic content of methanolic and aqueous extracts of the A.vera's flower and methanolic extract of date leaves were 32.40, 15.16 and 180.5 mg Tannic acid equivalents per g dry extract respectively. The total flavonoids content of methanolic and aqueous extracts of the A. vera and methanolic extract of date leaves were 6.46, 27.62 and 18.84 mg/ml Rutin equivalent per g dry extract respectively. The IC50 of methanolic and aqueous extracts of the A. vera and methanolic extract of date leaves in DPPH assay were 540.17, 406.04 and 7.43 µg/ml, in Hydroxyl radical scavenging assay were 0.1, 247.42 and 0.21 µg/ml., in ABTS+ radical scavenging assay were 44.72, 35.12 and 38.21 µg/ml, EC1 in FRAP assay were 4.84, 4.84 and 0.28 (mg/ml) respectively The results of Bleomycin assay showed that as the extract concentration increases, the pro-oxidant capacity of A. vera extracts increase and extract reduce. The results of this experiment show that the antioxidant capacity and polyphenol compound of the leaves of P. dactylifera was significantly higher than Aloe vera's flowers.