Composition des composés phénoliques et évaluation de leurs potentiels antioxydants : Cas de Citrullus lanatus et Cucumis melo.

Abstract

Watermelon (Citrullus lanatus) and melon (Cucumis melo) are plants used in phytotherapy for their many curative properties. In this study, the seeds of these two species were extracted by three different solvents (distilled water, 95% ethanol and 80% methanol) to perform photometric phytochemical analyzes to determine their phenolic compounds (total polyphenols, flavonoids , Flavonols and condensed tannins), and to evaluate the antioxidant activity by DPPH and ABTS. The results indicated the abundance of C. melo extracts in total polyphenols (EA: 21,123 ± 0,456mg EAG/g Lyo., EM: 17,78±0,232mg EAG/g Lyo., EE : 13.019±0.102mg EAG/g Lyo.), and flavonols (EA: 216.623 ±2.066mg ER/ g Lyo., EE: 140.755±0.286mg ER/g Lyo. EM: 75.635 ± 4.872 mg ER/g Lyo.) versus C. lanatus. While the latter contained more flavonoids (EE: 22.391 ± 0.427 mg ER /g Lyo., EM: 10.205 ± 0.061 mg ER /g Lyo., EA: 3.555 ± 0.112 mg ER /g Lyo), and tannins (EE: 208,116 ± 20,694mg ECT/g Lyo., EA: 70,5 ± 14,736mg ECT/g Lyo .; EM: 43,759 ± 9,792mg ECT/g Lyo.). DPPH inhibition rates were higher in C.lanatus (EE: 25.873 ± 0.796, EM: 22.424 ± 0.23, EA: 12.907 ± 3.437 vs EM: 8.842 ± 0.470, EE: 6.069 ± 0.359 EA: 4,885 ± 1,561mg /ml for C. melo). In addition, as ABTS was used only on C.lanatus, there was evidence of strong antioxidant activity (EM: 98.625±0.172, EE: 98.683±0.262, EA: 75.315±0.946 mg/ml). This justifies its use in phytotherapy and constitutes a potential for the development of an alternative to synthetic drugs.