Comparative Study of Essential Oil Composition, Anti-bacterial And Antioxidant Activities of the Aerial Parts of Thymus vulgaris Grown in Morocco and France

Abstract

Thymus vulgaris commonly known as thyme is an aromatic medicinal plant belonging to the Lamiaceae family. Two thyme essential oils grown in Morocco and France were investigated in this work. We analyzed their chemical composition and evaluated their antioxidant and antimicrobial effect. The chemical composition of essential oils was determined by gas chromatography/mass spectrometry. They were evaluated for their antibacterial activity against five marine pathogenic strains isolated from fish species identified as: Vibrio anguillarum, Photobacterium damselae subsp damselae, Aeromonas salmonicida, Edwarsiella tarda and Lactococcus garvieae. Then, the minimum inhibitory and bactericidal concentration values were determined. Furthermore, the antioxidant activity of the two essential oils was assessed in vitro by DPPH and ABTS assays. Thyme grown in France exhibited the greatest antibacterial activity against the studied strains in comparison with thyme grown in Morocco. Moreover, it showed the highest scavenging activity against free radicals produced by DPPH and ABTS with a percentage of 68.41% and 99.10% respectively, while thyme (Morocco) scavenged ABTS with 74.85%. The chemical components of the two essential oils revealed by the gas chromatography-mass spectrometry showed that thyme from France was mainly composed by thymol (35.77%), ortho-cymene (17.23%) and γ-terpinene (8.05%), while thyme from Morocco had borneol (31.04%), α-terpineol (15.16%), and carvacrol (7.13%) as the major constituents. These results showed the potential of thyme essential oils to be used in the aquaculture sector as phytobiotics to substitute chemicals and antibiotics weakening fish quality besides threatening the health of fish consumers.