Évaluation du pouvoir antioxydant des extraits de Ruta graveolens

Abstract

Ruta graveolens is a plant widely used in traditional medicine, known as "Fidjel". This work aims to study the phytochemical composition and evaluate the antioxidant activity of extracts from this plant. The extraction was carried out by macerating the powder of Ruta graveolens leaves, from the region of Zelfana (Ghardaïa), in three solvents: water, ethanol and ethyl acetate. The extraction yield results revealed significant variation among solvents, of which the ethanolic extract showed the highest yield (25.3%). Qualitative analysis carried out by phytochemical screening determined the presence of several chemical compounds, in particular tannins, flavonoids and alkaloids. Likewise, the colorimetric analysis revealed that the aqueous extract was the richest in total polyphenols (15.54 mg EAG/g DM), flavonoids (1.26 mg ER/g DM) and condensed tannins (0.035 mg EC/g DM), while the highest phenolic acid content was recorded for the ethyl acetate extract (0.134 mg EAC/g DM). The evaluation of the antioxidant activity of the different extracts was carried out in vitro by three chemical tests (DPPH, ABTS and FRAP). The highest inhibitory power of DPPH• and ABTS•+ radicals was obtained with the ethyl acetate extract with IC50 equal to 0.064 mg/mL and 0.032 mg/mL respectively. On the other hand, the aqueous extract has a high iron reducing capacity (A0.5 = 1.6 mg/mL). These results justify the traditional use of Ruta graveolens and confirm that their leaves exhibit a fairly significant antioxidant status.