Contenu phénolique et activité Antioxydante de Stipa tenacissima L. de la région de Sétif

Abstract

Stipa tenacissima L. (Poaceae) is a spontaneous herbaceous species found in the arid regions of North Africa. It is widely recognized for its traditional uses, closely linked to local customary practices, particularly for its antioxidant activity. The aim of this work is to valorize this plant through the quantification of polyphenols and the evaluation of the antioxidant potential of its etha-nolic extract. The estimation of total polyphenols and flavonoids revealed a high content, estimated respectively at 73.71 ± 0.17 mg GAE/g De and 38.65 ± 0.68 mg QE/g De . Antioxidant activity was assessed using three methods based on distinct mechanisms. The DPPH radical scavenging test revealed a marked scavenging effect, with an IC50 value of 0.07 ± 0.002 mg/ml. The ethanolic extract of Stipa tenacis-sima also showed a significant reducing power with an EC50 value of 0.33 ± 0.006 mg/ml, as well as a free iron chelation capacity, revealed by an IC50 value of 3.57 ± 0.16 mg/ml. These results high-light a notable antioxidant activity of the extract, related to its richness in secondary metabolites. These data suggest that this plant represents a promising natural source of antioxidant compounds, which can be valorized in the nutraceutical, therapeutic, and environmental fields. Keywords: Oxidative stress, Stipa tenacissima, polyphenols, flavonoids, antioxidant activity, DPPH, reducing power, iron chelation.