Chemical composition, antioxidant activities, in an allergic asthma model, of Olea europaea L. leaf extracts from Collo (Skikda, Algeria)

Abstract

This study is an attempt to characterize the chemical composition and antioxidant activity of olive leaves variety (namely Bouricha variety) that is very widespread in the East of Algeria. The aqueous extract (AE) of leaves was initially analyzed for its phenolic profile. Using the liquid chromatography coupled to tandem mass spectrometry analysis, it was possible to identify the predominant components in the AE of the leaves. This extract was hydrolyzed with acid and gave hydroxytyrosol (HT). AE and HT were evaluated for their 1,1-diphenyl-2-picrylhydrazyl radical scavenging capacity, ferric reducing antioxidant power and total antioxidant activity by phosphomolybdenum method. The antioxidant and anti-asthmatic activities of these extracts were examined in a model of experimental asthma in Wistar rats. For measuring the intensity of the airway inflammation, oxidative stress parameters were analyzed in lungs and a histological study of this tissue was performed. The obtained results showed that the sensitization of the ovalbumin (OVA) group induced lung inflammation and severe lipid peroxidation (LPO) revealed by a significant increase in malondialdehyde (MDA) levels and a decrease in the non-enzymatic and enzymatic antioxidant systems. However, the administration of AE and HT extracts significantly improved the antioxidant state in asthma disease and provided evidence for the relation between phenolic compounds and the high antioxidant activity of olive leaves extracts, especially HT more than AE.

Keywords:

• Olive leaf extract
• antioxidant activity
• allergic asthma model
• phenolic compounds
• lung inflammation
• LCMS
• hydroxytyrosol

Acknowledgments

The authors would like to thank the Algerian and Tunisian Ministries of Higher Education and Scientific Research (PNR: 33/DFPR/ATRSS, in Algeria) for the support of this research work via the Algero-Tunisian project. They also wish to extend their thanks to Mrs. Leila MAHFOUDHI, Emeritus teacher of English at the Sfax Faculty of Science, for having proofread and polished the language of this manuscript.

Disclosure statement

No potential conflict was reported by the authors.