Chemical composition and evaluation of biological effects of essential oil and aqueous extract of Lavandula angustifolia L.

Abstract

The present work was carried out to evaluate the phenolic compounds, the antibacterial, antifungal and antioxidant activities of essential oil (EO) and aqueous extract (AE) of Lavandula angustifolia L. The extracts were obtained by hydrodistillation, and by decoction method using water, then, total phenolics, flavonoids and condensed tannins were determined using Folin-Ciocalteu, Aluminium chloride, and Bate-Smith reaction methods, respectively. Afterward, the antibacterial activity was evaluated using the borth microdilution and, the antifungal activity was discussed using dilution technique in solid medium. To estimate the antioxidant effect of these extracts, the Total Antioxidant Capacity and DPPH scavenging methods were performed. Results of phytochemical analysis of AE showed that total phenolics, flavonoids and condensed tannins were 67.967 ± 0.139 mg GAE/g DW, 53.578 ± 0.418 mg QE/g DW and 9.194 ± 0.323 mg/g DW, respectively. In addition, spectral analysis by Gas Chromatography of EO showed the presence of four main components in oil lavender: Linalool (29.95%), Linalyl acetate (18.86%), ρ-cymene (14.68%), and α-Campholenal (10.26%). Furthermore, the antibacterial test showed that Staphylococcus aureus and Pseudomonas aeruginosa were the most resistant compared to the other tested strains. Also, it appears that EO had greater antifungal activity compared to AE, and the both showed significant antioxidant potential. These eminent results showed that the use of L. angustifolia L. as an anti-infective in traditional environments is justified and that it should be studied more widely in order to explore its potential.