Biological activities of essential oils extracted from Thymus capitatus (Lamiaceae)

Abstract

The present study aims to investigating, the chemical composition of the essential oil extracted from Thymus capitatus harvested in west, Algeria. It seeks the other objective to the determination of antioxidant, antibacterial and antifungal activities of oil in order to find new metabolite products, which are characterized by a biological activity. The investigations and research was carried out on the essential oil (EO) extracted from the dried leaves of Thymus Capitatus Lamiaceae that was harvested in the region of Tiart (West of Algeria). GC–MS analysis of EO is identified 22 components while thymol, carvacrol and γ-terpinene are the major components. The antioxidant activity of EO was evaluated by three methods: the DPPH test (2,2-diphenyl-1-1-picrirylhydrazil), the FRAP (Ferric reducing antioxidant power) and TAC (Total Antioxidant Capacity) test and compared with ascorbic acid, BHA (Butylated hydroxy anisole) and commercial thymol as standards. The results indicated that Thymus Capitatus oil showed higher antioxidant power in comparison with the standards with values of (0.61, 2.13 and 0.78) μg/mL for the DPPH, FRAP and TAC tests respectively. Also, the antibacterial activity of the oil was tested using the agar disc diffusion method, by determining the inhibition zone and the minimum inhibitory concentration (MIC). In this case, the results have shown a potential of the antibacterial activity than commercial antibiotics (Chloramphenicol, Cefoxitin, Gentamycin) against the tested strains, with MIC values of (29.44, 14.72, 14.72 and 7.36 μg/mL) for Staphylococcus aureus, S. typhi, E. coli and Streptococcus pneumoniae strains respectively. Furthermore, the antifungal study on the fungi of Cladosporium herbarum, Alternaria infectoria, Aspergillus Ochraceus, Trichophyton Sp reported significant results. The effectiveness of the oil showed that the essential oil has a fungicidal effect against the strains Cladosporium herbarum, Alternaria infectoria and a fungistatic effect against strains Aspergillus ochraceus and Trichophyton rubrum. The research outcomes clearly demonstrate that the essential oils of thymus capitatus can present an interesting alternative naturel which can be useful for food preservation and pharmaceutical treatment.