Polyphenols compound and Antioxidant Properties of the Aqueous Extract from Echium sp.

Abstract

Echium sp. is a desert plant belonging to the Boraginaceae family and is recognized for its richness in bioactive secondary metabolites. Consequently, this work aimed to determine the main phenolic compounds and evaluate the antioxidant potential of the aqueous extract prepared from the aerial parts of the plant. To achieve this, the phytochemical composition and antioxidant potential of the extract were evaluated using a series of complementary assays, including the determination of total polyphenols and flavonoids, Total Antioxidant Capacity (TAC), 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activity, hydrogen peroxide (H2O2) scavenging activity, hydroxyl radical (∙OH) scavenging activity, reducing power, ferrous ion chelating activity (iron chelation), and the β-carotene bleaching assay. Regarding the phytochemical profile, the extract exhibited a high total polyphenol content and a flavonoid content. The TAC assay revealed a significant antioxidant capacity compared to Vitamin C. The DPPH assay showed notable free-radical scavenging activity, while the BHT standard exhibited its own value. The ABTS assay demonstrated an even stronger radical-scavenging effect, whereas BHT exhibited its own reference value. The H2O2 scavenging assay indicated effective neutralization of hydrogen peroxide, while Vitamin C showed high scavenging activity. Likewise, the hydroxyl radical (∙OH) scavenging assay revealed considerable activity, compared to Vitamin C. The reducing power assay showed a pronounced electron-donating capacity, on the other hand, the BHT standard showed its comparison value. Furthermore, the iron chelation assay demonstrated a moderate ferrous ion chelating ability, compared with EDTA. Finally, the β-carotene bleaching assay showed high inhibition, confirming the extract’s capacity to prevent oxidative degradation in lipid systems, relative to BHT. In conclusion, these findings suggest that the aqueous extract of Echium sp. represents a promising natural source of antioxidants.