Étude comparative des composés phénoliques et de l’activité antioxydante de Senna occidentalis et Indigofera tinctoria

Abstract: Medicinal plants are an important source of natural antioxidants, capable of preventing oxidative stress and malnutrition-related diseases. Polyphenols were quantified using the Folin-Ciocalteu method.This study aimed to evaluate phytochemical and antioxidant properties of aqueous extracts of Indigofera tinctoria and Senna occidentalis leaves Polyphenols were quantified using the Folin-Ciocalteu method.Two free radical scavenging methods using 2,2-diphenyl-1-picryl hydrazyl (DPPH) and 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) were employed to evaluate antioxidant activity. The results showed that Indigofera tinctoria had higher polyphenol content (142.848 ± 17.462 mg EAG/ g) than Senna occidentalis (124.818 ± 11.035 mg EAG/ g). This difference is reflected in antioxidant activity: the IC50 values of I. tinctoria were lower for DPPH (49.948 ± 0.254 µg/mL) and ABTS (13.455 ± 2.221 µg/mL) than those of S. occidentalis (55.629 ± 1.287; 17.455 ± 1.28 µg/mL). Both extracts showed greater antioxidant efficacy with ABTS method, which can be explained by sensitivity of ABTS radical to hydrophilic and lipophilic antioxidants. Keywords: Indigofera tinctoria, Senna occidentalis, polyphenols, flavonoids, antioxidant, DPPH, ABTS.