Free radical scavenging and reducing power activities of aqueous extracts of Retama raetam

Abstract

The plant Retama raetam known as rtem, belong to Fabaceae family, is a desert shrub native to several countries of North Africa. The present study aims to evaluate the antioxidant activity of the aqueous extract of Retama raetam. Two Extracts were prepared: the decoction Aqueous extract (Aq.Ed) and the ultrasonic aqueous extract (Aq.Eu). Total polyphenol and flavonoid contents were quantified by the Folin-Ciocalteu and AlCl3, respectively. Results showed that Aq.Ed contains more polyphenols (65.90 ± 4.8μg GAE/ mg of dried extract) than Aq.Eu (57.92 ± 6.5μg GAE/mg of dried extract). However, flavonoids of the two extracts were very close, with 5.39 ± 1.32 μg QE/mg and 4.86 ± 1.30 μg QE/mg of dried extract, respectively. The antioxidant activity was examined using the DPPH and ABTS radicals scavenging assays and the reducing power assay. Results showed that Aq.Ed can scavenge DPPH• up to 87%, whereas the scavenging effect of Aq.Eu was 75%. Similarly to the DPPH• assay, both extracts exerted a considerable antioxidant activity toward ABTS•. Indeed, at 600μg/mL, Aq.Ed and Aq.Eu showed 89.79% and 75.47%, respectively. It is notable, that Aq.Ed is more potent than Aq.Eu. On the other hand, Retama raetam Aq.Ed and Aq.Eu exerted a powerful reducing ability with EC50 value of 227.79 ± 20.52μg/mL and 185.03 ± 70.24μg/mL, respectively. These results suggest that Retama raetam