Chemical Composition and Antioxidant Activity of Thymus fontanesii Essential Oil from Algeria

Abstract

Background: Thymus fontanesii is one of the important Algerian plants, used traditionally to treat the cough and cold. In addition, it may help to protect the people against lipid peroxidation and oxidative stress and can be used as an antioxidant agent for the preservation of processed food. Objective: The aim of this study was to determine the chemical composition of Algerian Thymus fontanesii essential oil and to test its antioxidant activity. Methods: The oil was extracted by electromagnetic induction (EMI) heating assisted extraction and by hydrodistillation, and was analysed by Gas Chromatography with Flame Ionization Detector (GC/FID) and Gas Chromatography/Mass Spectrometry (GC/MS). The antioxidant activity was evaluated by three assays mainly: DPPH assay, reducing power and β-carotene/linoleic acid. Results: The yield of the essential oil was varied from 2.1 ± 0.3 to 3.1 ± 0.1% (w/w), and from 1.8 ± 0.01 to 2.6 ± 0.02% (w/w), for the electromagnetic induction heating assisted extraction and hydrodistillation, respectively. Twenty seven components were identified representing 95.6 - 99.9% of the oil. Carvacrol (54.7 ± 1.2 - 63.9 ± 1.9%) was the major compound followed by p-cymene (9.2 ± 1.2 - 17.5 ± 1.2%) and γ-terpinene (8.8 ± 0.9 - 14.9 ± 0.8%). The Thymus fontanesii essential oil was found as a significant antioxidant with IC50 values ranging from 57.3 ± 1.4 to 236.7 ± 1.4 μg/mL, which were higher than that of butylated hydroxyl toluene (BHT) choosing as reference (9.1 ± 1.2 to 67.8 ± 0.1 μg/mL). Conclusion: The obtained results encourage the use of Thymus species with bioactive compounds for further food applications.