الخلاصة:
This work aims to valorize four plant species: Pituranthos chloranthus (Guezzah), Cleome
amblyocarpa (Netil), Cymbopogon schoenanthus (Lemmed), and Marrubium deserti de Noé
(Jâada), which grow spontaneously in the Ghardaïa region, located in the northern Algerian
Sahara. This is achieved through a contribution to their phytochemical study and the evaluation of
the antioxidant potential of aqueous crude extracts from their aerial parts. These plant species are
widely used by the local population for their numerous traditional therapeutic properties. They
belong to five different families: Capparaceae, Apiaceae, Lamiaceae, and Poaceae, and all are
xerophytic species to this end, phytochemical screening tests were carried out to identify the
presence or absence of key secondary metabolites. Aqueous maceration extractions were
performed, and the total polyphenol content of the crude extracts was determined. The antioxidant
activity of the extracts was evaluated against free radicals: DPPH, ABTS, and FRAP.
From the overall results obtained, the phytochemical screening tests revealed the presence of
certain secondary metabolites in all the studied species, particularly phenolic compounds, as well
as the absence of some other important compounds. Regarding the yield of the aqueous crude
extract, Marrubium deserti showed the highest yield, exceeding 50%. However, Cleome
amblyocarpa appeared to be richer in total polyphenols, with a content of 600.68 mg GAE/g dry
matter.The antioxidant activity assays allowed the evaluation of the capacity of the isolated extracts
to scavenge free radicals (DPPH and ABTS) and to reduce ferric ions to ferrous ions through the
FRAP test. The results showed that these extracts are highly active and exhibit strong antioxidant
power, particularly the extracts of Pituranthos chloranthus (P1) and Cymbopogon schoenanthus
(P4). Compared to standard antioxidants, the extracts of P1 and P4 generally showed superior
activity than Trolox. These results are very promising and partly justify the extensive traditional
medicinal use of these xerophytic species by the populations of the Algerian Sahara region.
