Etude phytochimique et Evaluation d’activité antioxydante de l’extrait aqueux et méthanolique d’Atriplex halimus

Abstract

Saharan spontaneous plants are very characteristic by their particular mode of adaptation to the desert environment which is very restrictive to their survival. Some species have pharmacological properties which make them of medicinal interest. In Algeria, we are trying to better understand the heritage of spontaneous species used in traditional medicine as well as their active ingredients. It is in this context that a phytochemical and antioxidant activity of Atriplex Halimus collected from BECHAR (Algeria) is being carried out : Through this study, we have demonstrated the existence of saponosides, flavonoids, coumarins and anthraquinones, with the exception of alkaloids and cardiac glycosides which are absent in the aqueous extract. The flavonoid content does not vary between the two extracts; the aqueous extract with a content of (22.53 ± 2.17) mg QE / g for the flavonoids. The methanolic extract is shown to have a value equal to the previous extract (22.51 ± 3.48) mg QE / g. In the determination of polyphenols, the content does not show a significant difference between the two extracts (20.30 ± 2.09 mg QE / g and 21.36 ± 1.02 mg QE / g) respectively. The antioxidant activity of the various extracts (aqueous and methanolic) was evaluated by three methods: Scavenging test for the free radical of DPPH (2,2-diphenyl-1-picrylhydrazyl), scavenging test for the free radical-cation of ABTS and the iron reduction test (FRAP). The aqueous extract and the methanolic extract exhibit good iron reducing capacity (FRAP) with an IC50 = 0.006 mg / ml, IC50 = 0.007mg / ml respectively. The capacity for trapping the free radical DPPH is very interesting with an IC50 = 1.002 ± 0.004 mg / ml; the latter remains lower than the capacity for trapping the DPPH radical of the methanolic extract, whose IC50 = 1.543 ± 0.028 mg / ml and the capacity for trapping the free radical-cation of ABTS with an IC50 = 1 ± 0.002 mg / ml of the aqueous extract and with an IC50 = 1.018 ± 0.011 mg / ml of the methanolic extract. Our study revealed that Atriplex halimus plant collected from Bechar region possesses potent antioxidant activity.