Chemical Composition, Antioxidant and Antimicrobial Activities of the Essential Oil of Origanum majorana Growing in Middle Atlas of Morocco

Abstract

The purpose of this work was to determine the chemical composition and assess the antibacterial and antioxidant activity of the essential oil of Origanum majorana grown in the Middle Atlas of Morocco. The yield of essential oil extracted by hydro-distillation is about 1 ± 0.05%.The chemical composition of the essential oil extracted from the Aerial parts of Origanum majorana was studied by gas chromatography coupled with mass spectrometry (GC/MS). The results of the GC-MS analysis of the volatile components of the EO revealed the presence of 21 components, representing 98.51% of the total essential oils (EOs). The main compounds were carvacrol (41.09%), terpinen-4-ol (28.08%), followed by p- Cis-Sabinene hydrate (21.12%), γ-Terpinene (2.7%), Spathulenol (1.5%) and thymol (1.32%). Antioxidant activity was determined by the DPPH and FRAP assays. The results demonstrated that our EOs exhibit a significant antiradical effect with an IC50 value of 0.25 mg/mL compared to the pure reference antioxidant BHT with an IC50 value of 0.11 mg/mL. The antibacterial effect of this essential oil was tested against five bacterial strains.Staphylococcus aureus was the most sensitive with a MIC value of 1.98 ± 0.01, followed by Klebsiella pneumonia with an MIC value of 2.01 ± 0.35ug/ml. The results show that Origanum majorana essential oil process antibacterial and antioxidant properties and it can be used as a natural food preservative and as an antimicrobial agent for the treatment of several infectious diseases caused by bacteria.