Études phytochimique et activité biologique des extraits végétaux.

Abstract

This study aims to evaluate the chemical properties and antioxidant activity of Cymbopogon citratus (Lemongrass), belonging to the Poaceae family and collected from the region of El-Kherba, Mila province. For this purpose, a hydroethanolic extraction was performed on the leaves of this species, followed by fractionation using solvents of increasing polarity. Phytochemical screening of the crude extract was carried out, and the total phenolic content (TPC) and total flavonoid content (TFC) were determined. The antioxidant activity of the obtained extracts was assessed using the DPPH method. The results showed that the highest extraction yield was recorded for the aqueous extract, 10.0948%. Phytochemical screening revealed the presence of several chemical groups such as flavonoids, tannins, phenols, sterols, and terpenoids. The measurement of TPC and TFC in the five extracts showed wide variation, with the highest TPC recorded in the aqueous extract 229.14 ± 6.64 μg EAG/mg Extr, while the highest TFC was found in the ethyl acetate extract 328.16 ± 5.30 μg ER/mg Extr. The evaluation of antioxidant activity also revealed significant variation among the tested extracts, with the ethyl acetate extract showing the best antioxidant capacity with an IC₅₀ of 82.07 μg/mL, though still high compared to the standard ascorbic acid, IC₅₀ = 3.52 μg/mL. These findings suggest that Cymbopogon citratus is a promising source of bioactive compounds, especially those with antioxidant potential. However, further studies are needed to fully explore and valorize its properties