Activité antioxydante des extraits hydrométhanoliques des feuilles et des différentes parties du fruit de Cucumis melo « amloun n’waghlène » (Cucurbitaceae) récoltés dans la région de Ghardaïa

Abstract

The present study aims to evaluate for the first time the phenolic composition of the hydromethanolic extracts of the leaves and the different parts of the local M'zab Cucumis melo fruit known as "amLoun n'waghlène" and their antioxidant activities. The extraction of the active ingredients has been carried out by maceration using a methanol / water solvent system. The phytochemical study was conducted using qualitative and quantitative tests to demonstrate the presence and quantification of certain metabolites, particularly secondary metabolites. The evaluation of the biological activity has been performant by two tests namely: ABTS and FRAP. The results of the phytochemical screening reveal the richness of different extracts in different types of metabolites such as tannins, cyanidines, coumarins, quinones, alkaloids, terpenes and finally reducing compounds. At the end of the various assays carried out, the results obtained indicate that the highest contents of polyphenols, flavonoids, phenolic acids and condensed tannins are recorded for the extracts of the pulp (19906,96 ± 2430,72 μg EAG/g), fluid from the central cavity of the fruit (5856,05 ± 583,98 μg ER / g and 3235,18 ± 353,33 μg EAC/g) and melon bark (3739,71± 206,85 μg EC/g). The leaf extract has the lowest levels in these compounds. Regarding the antioxidant activity, all the extracts studied showed a more powerful antioxidant activity and very remarkable in comparison with those of the standard antioxidant (Trolox). The most effective extract in the inhibition of the radical cation ABTS -+ and the reduction of iron is that of leaves with IC50 values of 3,40 ± 0,57 μg/mL and 15,65 ± 1,18 μg/mL respectively.