Abstract:
In recent decades, there has been a growing interest in the study of medicinal plants and their traditional use for the treatment of various diseases. The olive tree, or Olea europaea L., is an inseparable entity of the Mediterranean peoples. This plant belongs to the large family of Oleaceae. The aim of this study was to evaluate the antioxidant activity of aqueous and methanolic extracts of olive roots and bark, respectively (RAE, RME, BAE, and BME). The determination of total polyphenols by the Folin-Ciocalteu method revealed the richness of RME and BME extracts in phenolic compounds; the contents are respectively, 509.33 μgGAE/mg and 387.33 g GAE/mg of extract. The radical scavenging activity towards DPPH showed that BME and RME extracts are the most active, with an IC₅₀ of 0.404 mg/mL and 0.525 mg/mL, respectively. In the ß-carotene bleaching assay, the extracts RAE, BME, and BAE exhibited the highest inhibitory activities, with 90.19%, 86.15%, and 78.05%, respectively. The antioxidant activity of RME extract is confirmed on oxidative homolysis of red blood induced by H₂O₂ with a percentage of inhibition (21%). These findings provide evidence that Olea europea bark and roots are potential sources of antioxidant which have many benefits towards human health.

Keywords: Polyphenols,  Olea europea, Scavenging, Hemolysis, β caroten.